KR20150136097A - Polarizing plate, method for producing same and liquid crystal display device - Google Patents

Abstract

Disclosure of the Invention Problems to be Solved by the Invention It is an object of the present invention to provide a polarizing plate using an acrylic film and a cellulose ester film as protective films of polarizers in a liquid crystal display device, And the deterioration of the polarizer adhesion of the polarizer is not exhibited. The polarizing plate of the present invention is a polarizing plate in which a polarizer is sandwiched between a film A and a film B via an active line curable adhesive layer and the film A has a film thickness within a range of 20 to 60 탆, Wherein the film B contains cellulose acetate having a film thickness in the range of 20 to 60 占 퐉 and an average degree of acetyl group substitution in the range of 2.0 to 2.5, Wherein the film is a cellulose acetate film having the same dimensional change characteristics within the specific range.

Description

TECHNICAL FIELD [0001] The present invention relates to a polarizing plate, a method of manufacturing the same, and a liquid crystal display device.

The present invention relates to a polarizing plate, a manufacturing method thereof, and a liquid crystal display device. More specifically, when a polarizing plate using an acrylic film and a cellulose acetate film as a protective film of a polarizer is provided in a liquid crystal display device, the polarizing plate does not show display irregularities of the liquid crystal panel and deterioration of polarizer adhesion even when the environment of temperature and humidity in use changes. A manufacturing method thereof, and a liquid crystal display device provided with the polarizing plate.

In recent years, since a liquid crystal display device is required to be larger and thinner, a polarizing plate provided in a liquid crystal display device is also required to be larger and thinner. Specifically, it is desired to reduce the thickness of a polarizing plate protective film used as a polarizer or a protective film constituting a polarizing plate. However, from the viewpoint of thinning the polarizing plate, there is a problem that when the cellulose ester film (for example, triacetylcellulose (TAC) film or the like) usually used as a protective film is thinned, the film strength and planarity are reduced. The following thin film film causes deterioration of the physical properties of the film, and therefore, realization of thinning of the polarizing plate is obstructed.

Attempts have been made to increase the strength of the protective film for the polarizing plate and to improve the adhesion of the polarizing film and the protective film in order to improve the strength of the polarizing plate having the thin protective film. For example, for the purpose of increasing the strength of a protective film for a polarizing plate, there has been proposed an acrylic film using an acrylic resin which is excellent in transparency and dimensional stability and is a low hygroscopic resin (see, for example, Patent Document 1) . However, such an acrylic film is not suitable for a retardation film for the purpose of enlarging a viewing angle of a VA mode liquid crystal display or the like, since the acrylic film has a property that a retardation is difficult to be revealed.

Therefore, for example, as the film disposed on the liquid crystal cell side of the VA mode liquid crystal display device, a conventional cellulose ester resin is preferably used as the film from the viewpoints of ease of occurrence of phase difference, productivity (handling property, reworkability, (A form of a cellulose ester film or a cellulose acetate film in the present invention) containing an acrylic film / polarizer / cellulose ester resin from the viewer side as a constitution of the polarizing plate .

On the other hand, as a method for improving the adhesion between the polarizer and the protective film, for example, a method of bonding a polarizer and a cellulose ester film through an active ray curable adhesive is disclosed (for example, see Patent Document 2). According to this method, it is possible to obtain a polarizing plate which is less prone to discoloration of the polarizer (polarizing film) even under harsh environmental conditions such as high temperature and high humidity, and has high durability against adhesion and the like.

However, according to the detailed study of the present inventor, when a liquid crystal display equipped with a polarizing plate of a thin film constituting the acrylic film / polarizer / cellulose ester film is moved under a low temperature and low humidity atmosphere in a high temperature and high humidity atmosphere, It was found that a display unevenness peculiar to the liquid crystal panel occurs. In addition, when the film was adhered using the active ray-curable adhesive, the range of the display unevenness was enlarged. This is because, in particular, when the temperature and humidity environment of the use environment changed sharply, The speed of change was different and it was assumed that the film was caused by optical irregularity caused by distortion of two films and an adhesive portion sandwiching the polarizer.

In addition, the adhesion between the polarizer and the protective film is deteriorated by the distortion, and when the temperature and humidity environment changes in a harsh environment than in the prior art, there is a problem that the protective film is cried or film peeling is likely to occur.

Japanese Patent Application Laid-Open No. 2012-237818 Japanese Patent Application Laid-Open No. 2010-230806

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems and its object is to provide a polarizing plate in which a polarizer is bonded to a protective film through an active ray curable adhesive layer and an acrylic film and a cellulose acetate film are used as the protective film, It is another object of the present invention to provide a polarizing plate which does not exhibit display unevenness of a liquid crystal panel, crying of a protective film, and deterioration of polarizer adhesion such as peeling off even when the polarizing plate is provided in a liquid crystal display device. It is another object of the present invention to provide a method for producing such a polarizing plate and a liquid crystal display device provided with the polarizing plate and having excellent visibility.

In order to solve the above problems, the present inventors have found that a polarizer in which a polarizer is interposed between a film A and a film B via an active ray curable adhesive layer, Characterized in that the film B is a cellulose acetate film having a low degree of substitution and the cellulose acetate film is a thin film and the dimensional change is also within a specific range in the same manner, The present invention has been accomplished on the basis of these findings. The present invention has been accomplished on the basis of these findings.

That is, the above object of the present invention is solved by the following means.

1. A polarizing plate in which a polarizer is sandwiched between a film A and a film B via an active ray curable adhesive layer,

Wherein the film A is an acrylic film containing an acrylic resin and having a film thickness in a range of 20 to 60 탆 and satisfying the following formulas (1) to (4)

Wherein the film B contains cellulose acetate having a film thickness in the range of 20 to 60 占 퐉 and an average degree of acetyl group substitution in the range of 2.0 to 2.5 and satisfying the following formulas (1) to (4) Wherein the polarizer is an acetate film.

(1) 0.03 (%)? L ₁ MD-L ₅ MD? 0.30 (%)

(2) 0.03 (%)? L ₁ TD-L ₅ TD? 0.30 (%)

(3) 0 (%)? L ₅ MD-L ₃₀ MD? 0.10 (%)

(4) 0 (%)? L ₅ TD-L ₃₀ TD? 0.10 (%)

In the above formula, L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD are calculated by the following equations (a) to (f) And the dimensional change rate of the film after 30 minutes. The following formulas (a) to (f) show the film A and the film B taken in a rectangular shape so that one side is parallel to the TD direction or the MD direction, and the film A and the film B are left for 24 hours under conditions of 23 ° C and 55% The predetermined dimensions are measured in the MD direction and the TD direction, and are referred to as L ₀ MD and L ₀ TD, respectively. The film was allowed to stand in a constant temperature and humidity bath at 80 캜 and 90% RH for 1 hour and left under a temperature and humidity environment of 23 캜 and 55% RH to measure the dimension after one minute, the dimension after five minutes, TD, and L30TD ', L30MD', and L30TD ', respectively, and substituting the following equations (a) to (f) to determine the rate of dimensional change: L1MD', L1TD ', L5MD', L5MD '

Dimensional change rate after 1 minute

(Formula 1) L ₁ MD (%) = (L ₁ MD '- L ₀ MD) / L ₀ MD × 100

(Expression b) L ₁ TD (%) = (L ₁ TD'-L ₀ TD) / L ₀ TD × 100

Dimensional change rate after 5 minutes

(C) L ₅ MD (%) = (L ₅ MD'-L ₀ MD) / L ₀ MD x 100

(Formula d) L ₅ TD (%) = (L ₅ TD'-L ₀ TD) / L ₀ TD x 100

Dimensional change rate after 30 minutes

L ₃₀ MD (%) = (L ₃₀ MD'-L ₀ MD) / L ₀ MD x 100

(Formula f) L ₃₀ TD (%) = (L ₃₀ TD'-L ₀ TD) / L ₀ TD x 100

2. The polarizer of claim 1, wherein the film A and the film B satisfy the following formulas (5) to (8), respectively.

(5) 0.05 (%)? L ₁ MD-L ₅ MD? 0.15 (%)

(6) 0.05 (%)? L ₁ TD-L ₅ TD? 0.15 (%)

(7) 0 (%)? L ₅ MD-L ₃₀ MD? 0.05 (%)

(8) 0 (%)? L ₅ TD-L ₃₀ TD? 0.05 (%)

In this equation, L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD are synonymous with the first term.

3. The polarizing plate according to claim 1 or 2, wherein L ₃₀ TD and L ₃₀ MD of the film A and the film B are in the range of -0.10 to 0.10%, respectively.

4. The polarizing plate according to any one of claims 1 to 3, wherein the film A contains a sugar ester or a polycondensation ester having a structure represented by the following formula (1).

(1)

(Wherein B ₃ and B ₄ each independently represent an aliphatic or aromatic monocarboxylic acid residue or a hydroxyl group, G ₂ represents an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol having 6 to 12 carbon atoms Or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n is an integer of 1 or more Represents an integer.)

5. The film according to any one of claims 1 to 4, wherein the film A comprises at least three layers each having a skin layer on both sides of the core layer, the core layer contains an acrylic resin, and the skin layer contains a cellulose ester. 5. The polarizing plate according to any one of claims 1 to 4,

6. The polarizing plate according to any one of claims 1 to 5, wherein the film A is stretched in the range of 1.05 to 1.5 times the original width in the TD direction.

7. The film B, wherein the retardation value Ro in the in-plane direction defined by the following formulas (i) and (ii) is in the range of 40 to 60 nm and the retardation value Rt in the thickness direction is in the range of 100 to 140 nm Of the polarizing plate according to any one of claims 1 to 6.

Formula (i): Ro = (n x -n y) × d (nm)

Formula (ii): Rt = {( n x + n y) / 2-n z} × d (nm)

[In the formulas (i) and (ii), n _x represents the refractive index in the direction x at which the refractive index becomes maximum in the in-plane direction of the film. n _y represents the refractive index in the in-plane direction of the film and in the direction y perpendicular to the direction x. and n _z represents the refractive index in the thickness direction z of the film. and d represents the thickness (nm) of the film. Measurement is carried out at a measurement wavelength of 590 nm under an environment of 23 ° C and 55% RH.]

8. The polarizing plate according to any one of claims 1 to 7, wherein the film B contains cellulose acetate having an acetyl group average degree of substitution in the range of 2.1 to 2.4.

9. The polarizing plate according to any one of claims 1 to 8, wherein the film B contains a sugar ester or a polycondensation ester having a structure represented by the following formula (1).

(1)

(Wherein, B ₃ and B ₄ are each independently an aliphatic or aromatic mono-carboxylic acid residue, or a hydroxy. G ₂ is alkylene having 2 to 12 glycol residue, an aryl glycol residue having 6 to 12 carbon atoms Or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n is an integer of 1 or more Lt; / RTI >

10. The film B has at least three layers having a skin layer on both sides of the core layer, the core layer containing cellulose acetate having an acetyl group degree of substitution in the range of 2.0 to 2.45, The polarizing plate according to any one of claims 1 to 9, characterized by containing cellulose acetate having a degree of substitution in the range of 2.6 to 2.95.

11. The polarizing plate according to any one of claims 1 to 10, wherein the polarizer has a thickness in the range of 2 to 15 占 퐉.

12. A method of producing a polarizing plate for bonding a film A and a film B to both surfaces of a polarizer through an active line curable adhesive layer,

As the film A, an acrylic film containing an acrylic resin having a film thickness in the range of 20 to 60 탆 and satisfying the following formulas (1) to (4) was used,

Wherein the film B contains cellulose acetate having a film thickness in the range of 20 to 60 占 퐉 and an average degree of acetyl group substitution in the range of 2.0 to 2.5 and satisfying the following formulas (1) to (4) Acetate film is used as the polarizing plate.

(1) 0.03 (%)? L ₁ MD-L ₅ MD? 0.30 (%)

(2) 0.03 (%)? L ₁ TD-L ₅ TD? 0.30 (%)

(3) 0 (%)? L ₅ MD-L ₃₀ MD? 0.10 (%)

(4) 0 (%)? L ₅ TD-L ₃₀ TD? 0.10 (%)

In the above formula, L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD are calculated by the following equations (a) to (f) And the dimensional change rate of the film after 30 minutes. The following formulas (a) to (f) show the film A and the film B taken in a rectangle so that one side is parallel to the TD direction or the MD direction, and the film A and the film B are left for 24 hours under a temperature and humidity environment of 23 캜 and 55% The predetermined dimensions are measured in the MD direction and the TD direction, and are referred to as L ₀ MD and L ₀ TD, respectively. The film was allowed to stand in a constant temperature and humidity bath at 80 캜 and 90% RH for 1 hour and left under a temperature and humidity environment of 23 캜 and 55% RH to measure the dimension after one minute, the dimension after five minutes, respectively measured in the TD direction, respectively, _{L 1 MD ', L 1 TD} ', L 5 MD ', L 5 TD', L 30 MD ', and L ₃₀ TD' La, and the following formula (a) to (f) And the dimensional change rate is obtained.

Dimensional change rate after 1 minute

(Formula 1) L ₁ MD (%) = (L ₁ MD '- L ₀ MD) / L ₀ MD × 100

(Expression b) L ₁ TD (%) = (L ₁ TD'-L ₀ TD) / L ₀ TD × 100

Dimensional change rate after 5 minutes

(C) L ₅ MD (%) = (L ₅ MD'-L ₀ MD) / L ₀ MD x 100

(Formula d) L ₅ TD (%) = (L ₅ TD'-L ₀ TD) / L ₀ TD x 100

Dimensional change rate after 30 minutes

L ₃₀ MD (%) = (L ₃₀ MD'-L ₀ MD) / L ₀ MD x 100

(Formula f) L ₃₀ TD (%) = (L ₃₀ TD'-L ₀ TD) / L ₀ TD x 100

13. The film A,

A step of forming a web on a metal support by softening at least a dope containing an acrylic resin and an organic solvent,

Drying the formed web to separate it from the metal support,

A step of stretching the peeled web;

A step of drying the drawn web in a dryer zone,

And a cooling step of cooling the web at a speed in a range of 50 to 100 DEG C / sec after the web leaves the dryer zone

The polarizing plate according to claim 12,

14. The film (B)

A step of forming a web on a metal support by softening a dope containing at least cellulose acetate and an organic solvent,

Drying the formed web to separate it from the metal support,

A step of stretching the peeled web;

A step of drying the elongated web in a dryer zone

, The step of drying the web in the dryer zone is maintained at a temperature within the range of 130 to 150 DEG C and the B side opposite to the A side of the web is alternately turned inwardly by the conveying roller bending has a bending process, the bending step the art, when the radius of the web when bent to the art have a d (mm), is within the range of the value of 1 / a ^-1 0.035mm to 0.050mm ^-1, also The method of manufacturing a polarizing plate according to claim 12 or 13, wherein the bending is repeated 50 times or more and less than 120 times.

15. A method for producing a laminated film, comprising the steps of: forming a polyvinyl alcohol-based resin layer on one surface of a base film in which a rubber component is dispersed in a thermoplastic resin to obtain a laminated film;

A step of uniaxially stretching the laminated film to obtain a stretched film,

A step of staining the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to obtain a dye film,

A step of immersing the polyvinyl alcohol-based resin layer of the dye film in a solution containing a crosslinking agent to form a polarizer layer to obtain a crosslinked film,

A step of drying the crosslinked film

To form a polarizing laminated film,

The polarizing plate according to any one of claims 12 to 14, characterized in that the polyvinyl alcohol-based resin layer of the polarizing laminated film is peeled from the base film to use the polyvinyl alcohol-based resin layer as the polarizer A method for producing a polarizing plate.

16. A liquid crystal display device comprising the polarizing plate according to any one of claims 1 to 11.

17. The liquid crystal display device according to claim 16, wherein the liquid crystal display device is a VA mode liquid crystal display device.

When the polarizer is bonded to the protective film via the active ray curable adhesive layer by the above means of the present invention and the polarizing plate is provided in the liquid crystal display device using the acrylic film and the cellulose acetate film as the protective film It is possible to provide a polarizing plate which does not exhibit deterioration in polarizer adhesion such as unevenness of display on a liquid crystal panel, crying phenomenon, and film peeling even if the temperature and humidity environment of the use environment changes. In addition, it is possible to provide a method for producing the polarizing plate and a liquid crystal display device having excellent visibility including the polarizing plate.

Although the mechanism and mechanism for manifesting the effects of the present invention are not clarified, they are estimated as follows.

The polarizer is bonded to the protective film via the active ray curable adhesive layer and the polarizing plate of the thin film constituting the acrylic film / polarizer / cellulose acetate film is moved in a low temperature and low humidity atmosphere under a high temperature and high humidity atmosphere to move the liquid crystal display device There is a problem that display unevenness peculiar to the liquid crystal panel is generated. This is because, in particular, when the temperature and humidity environment of the environment is drastically changed, the speeds of the dimensional changes of the two protective films are different, so that distortion occurs between the two protective films and the adhesive portions sandwiching the polarizer, It is presumed that this is due to the optical unevenness that follows.

The inventor of the present invention has found that even if the dimensional change of a film after a relatively long period of time such as day and night is adjusted under a specific environment in the process of examining the rate of dimensional change of the protective film, Humidity environment of the environment from a rapid change of the environment to a speed of dimensional change over a relatively short period of time. As a result, in the acrylic film and various cellulose ester films, a specific dimensional change It is presumed that the problems of the present invention can be improved by adjusting the difference in the behavior of the dimensional changes.

Fig. 1 is a graph showing the results of evaluation of the effect of the above formula (a) on the acrylic film after 1 minute, 5 minutes, 30 minutes, and 60 minutes immediately after the environment change (under the environment of 80 deg. C and 90% (%) In the MD direction and the TD direction expressed by the following formulas (1) to (f).

It can be seen that the acrylic film has a stable behavior in which the dimension fluctuates (shrinks) from 1 minute to 5 minutes later, and thereafter hardly changes in dimension.

2 is a schematic diagram showing a similar dimensional change of a triacetyl cellulose film (TAC film).

The triacetylcellulose film differs greatly from an acrylic film, and when the film is moved under a high-temperature and high-humidity and low-temperature and low-humidity environment, the film slightly expands, and the fluctuation (shrinkage) continues thereafter.

3 is a schematic diagram showing the same dimensional change of a cellulose acetate propionate film (CAP film).

Unlike the acrylic film, the cellulose acetate propionate film largely fluctuates (shrinks) from 1 minute to 5 minutes later, and then continues to fluctuate (shrink).

4 is a schematic diagram showing a similar dimensional change of a diacetylcellulose film (DAC film).

The diacetyl cellulose film exhibits a slightly larger dimensional fluctuation (shrinkage) than the acrylic film during 1 minute to 5 minutes, but after that, it takes a stable behavior with almost no dimensional change as in the case of the acrylic film.

As a result of the above examination, if the dimensional change from 1 to 5 minutes after the environment change of the diacetyl cellulose film can be adjusted by any means so as to approximate the behavior of the acrylic film, It was presumed that two pieces of protective films could be formed and the distortion between the polarizer and the adhesive portion could be reduced.

Therefore, a film containing diacetylcellulose as the acrylic film and the cellulose acetate film as the two protective films, which is a technical feature of the polarizing plate of the present invention, is adopted and adjusted so that the dimensional change during each of the short- It is possible to suppress the distortion in the protective film and the adhesive portion, and it is possible to reduce display irregularities appearing on the liquid crystal panel even if the temperature and humidity environment of the use environment changes, It is presumed that a polarizing plate free from deterioration will be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing a dimensional change of an acrylic film in a short time.
2 is a schematic diagram showing a dimensional change of a triacetylcellulose film in a short time.
3 is a schematic diagram showing a dimensional change of a cellulose acetate propionate film in a short time.
4 is a schematic diagram showing the dimensional change of the diacetyl cellulose film in a short time.
Fig. 5 is a schematic diagram showing the dimensional change of the film B (modified diacetylcellulose film) according to the present invention in a short time.
6 is a schematic diagram for measuring the dimensional change of the film.
7 is a schematic diagram showing an example of a dope manufacturing process, a softening process and a drying process of a preferable solution casting film-forming method of a cellulose ester film according to the present invention.
Fig. 8 is a schematic diagram showing the formation of a shared stretch die and a flexible multi-layer web.
9 is a schematic view of a bending treatment apparatus that can be preferably applied to the present invention.

The polarizing plate of the present invention is a polarizing plate in which a polarizer is sandwiched between a film A and a film B via an active ray curable adhesive layer, wherein the film A is an acrylic film having a thin film and a dimensional change under specific conditions, Characterized in that the film B is a cellulose acetate film containing cellulose acetate having a low degree of substitution and being a thin film and having a dimensional change within the specified range. When such a polarizing plate is provided in a liquid crystal display device, Which does not cause display unevenness of the liquid crystal panel and deterioration of the polarizer adhesion even when the polarizer is changed. This feature is a technical feature that is common to the invention according to claims 1 to 17.

In the present invention, MD is an abbreviation of Machine Direction, and MD direction is a direction in which a film called a flexible direction and a longitudinal direction is transported at the time of film formation. TD is an abbreviation of Transverse Direction, and the TD direction is a direction perpendicular to the conveying direction, which is generally called a width direction and a transverse direction.

In the present specification, the film A and the film B may be simply referred to as a protective film.

As an embodiment of the present invention, it is preferable that the film A and the film B are polarizing plates satisfying the range of dimensional change represented by the above-mentioned formulas (5) to (8) from the viewpoint of manifesting the effect of the present invention, The L ₃₀ TD and the L ₃₀ MD of the film A and the film B are within the range of -0.10 to 0.10%, respectively, so that occurrence of display unevenness of the liquid crystal panel can be suppressed even when the environment of the temperature and humidity of the use environment abruptly changes, Is a preferable form from the viewpoint that the durability against deterioration of the adhesion with the polarizer is further improved.

Further, it is preferable that the film A contains a sugar ester or a polycondensation ester having the structure represented by the formula (1) from the viewpoint of reducing the dimensional change due to its plastic effect, and the film A (1), wherein the core layer contains an acrylic resin, and the skin layer contains a cellulose ester, by overlapping different kinds of resins, wherein the core layer comprises an acrylic resin and the skin layer has a skin layer on both sides of the core layer. To (4) within the range of the dimensional change represented by (4). Further, the film A is stretched within the range of 1.05 to 1.5 times the original width in the TD direction. By increasing the orientation of the molecular chains of the acrylic resin, it is possible to reduce the dimensional change due to the entry and exit of moisture, The display irregularity of the panel and the effect of improving the polarizer adhesion can be more easily expressed.

The film B has a retardation value Ro in an in-plane direction defined by the above-mentioned formulas (i) and (ii) within a range of 40 to 60 nm and a retardation value Rt in a thickness direction within a range of 100 to 140 nm Is preferable from the viewpoint of increasing the viewing angle of the liquid crystal display device and improving visibility. In order to express the retardation value, it is preferable that cellulose acetate having an acetyl group average degree of substitution in the range of 2.1 to 2.4 is contained.

Further, in order to stabilize the dimensional change, it is preferable that the film B contains a sugar ester or a polycondensation ester having a structure represented by the above formula (1) because it exhibits its plastic effect, Is composed of at least three layers each having a skin layer on both sides of the core layer and the core layer contains cellulose acetate having an acetyl group substitution degree in the range of 2.0 to 2.45, and the skin layer has a degree of acetyl group substitution in the range of 2.6 to 2.95 (1) to (4) can be more easily controlled by overlapping different kinds of resins, and the influence of the humidity fluctuation of the environment on the film Can be made small.

It is preferable that the polarizer has a thickness in the range of 2 to 15 탆 from the viewpoint of thinning the entire polarizing plate and the flexibility of the polarizer is increased so that it is easy to follow the dimensional change of the protective film. It is possible to further improve the adhesion between the polarizer and the protective film when used, and also to reduce the display unevenness.

A method of producing a polarizing plate of the present invention is a method of producing a polarizing plate for bonding a film A and a film B to each other via both sides of a polarizer with an active ray curable adhesive layer interposed therebetween. An acrylic film containing the acrylic resin is used as the film A , And the production method using the cellulose acetate film as the film B is preferable in producing a polarizing plate exhibiting the effect of the present invention.

The film A is formed by a cooling step of cooling the web at a speed in a range of 50 to 100 ° C / sec after the step of drying the stretched web in the dryer zone in the forming step, whereby the state of the molecular chain of the film The amount of water that can be contained in the film can be adjusted, and the shrinkage ratio of the film containing moisture can be controlled effectively.

In the film B, in the forming step, the step of drying the web is carried out so that the B side opposite to the A side of the web is alternately inwardly located inside the dryer zone maintained within the specified temperature range, Has a bending process in which the bending process is carried out by repeating the bending process within a specific range within a specific range when the web is bent and forming the bending process so that the state of the molecular chain of the film is dense, It is preferable to control the shrinkage ratio of the film containing moisture by adjusting the amount of water that the film can contain.

As the polarizer, a polyvinyl alcohol-based resin layer is formed on one surface of a base film in which a rubber component is dispersed in a thermoplastic resin, and then a monoaxial stretching, dyeing, crosslinking, It is preferable that the polyvinyl alcohol-based resin layer of the polarizing laminated film is peeled off from the base film to form the polarizer, since a thin polarizing plate of high quality can be obtained.

The polarizing plate of the present invention is suitably provided in a liquid crystal display device, and is particularly suitable for a VA mode liquid crystal display device.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, " to " is used to mean that the numerical values described before and after the lower limit and the upper limit are included.

≪ Outline of polarizer of the present invention &

The polarizing plate of the present invention is a polarizing plate in which a polarizer is sandwiched between a film A and a film B via an active ray curable adhesive layer,

Wherein the film A is an acrylic film containing an acrylic resin and having a film thickness in a range of 20 to 60 탆 and satisfying the following formulas (1) to (4)

Wherein the film B contains cellulose acetate having a film thickness in the range of 20 to 60 占 퐉 and an average degree of acetyl group substitution in the range of 2.0 to 2.5 and satisfying the following formulas (1) to (4) Acetate film.

(1) 0.03 (%)? L ₁ MD-L ₅ MD? 0.30 (%)

(2) 0.03 (%)? L ₁ TD-L ₅ TD? 0.30 (%)

(3) 0 (%)? L ₅ MD-L ₃₀ MD? 0.10 (%)

(4) 0 (%)? L ₅ TD-L ₃₀ TD? 0.10 (%)

In the above formula, L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD satisfy the following equations (a) to (f) Of the film after a minute. The following formulas (a) to (f) show the film A and the film B taken in a rectangle so that one side is parallel to the TD direction or the MD direction, and the film A and the film B are left for 24 hours under a temperature and humidity environment of 23 캜 and 55% The predetermined dimensions are measured in the MD direction and the TD direction, and are referred to as L ₀ MD and L ₀ TD, respectively. The film was allowed to stand in a constant temperature and humidity bath at 80 캜 and 90% RH for 1 hour and left under a temperature and humidity environment of 23 캜 and 55% RH to measure the dimension after one minute, the dimension after five minutes, each measured, and each L ₁ MD ', L ₁ TD', L ₅ MD ', L ₅ TD', L ₃₀ MD to La ', and L ₃₀ TD' of formula in the TD direction (a) to (f) And the dimensional change rate is obtained.

Dimensional change rate after 1 minute

(Formula 1) L ₁ MD (%) = (L ₁ MD '- L ₀ MD) / L ₀ MD × 100

(Expression b) L ₁ TD (%) = (L ₁ TD'-L ₀ TD) / L ₀ TD × 100

Dimensional change rate after 5 minutes

(C) L ₅ MD (%) = (L ₅ MD'-L ₀ MD) / L ₀ MD x 100

(Formula d) L ₅ TD (%) = (L ₅ TD'-L ₀ TD) / L ₀ TD x 100

Dimensional change rate after 30 minutes

L ₃₀ MD (%) = (L ₃₀ MD'-L ₀ MD) / L ₀ MD x 100

(Formula f) L ₃₀ TD (%) = (L ₃₀ TD'-L ₀ TD) / L ₀ TD x 100

The present inventors have found that an acrylic film using an acrylic resin which is excellent in transparency and dimensional stability and which is a low hygroscopic resin is used for one side of the polarizer in order to improve the strength of the polarizer in the thinning of the polarizer, A retardation film containing a conventional cellulose ester resin is used as the retardation film from the viewpoints of easiness of development of the retardation, productivity (handling property, reworkability, etc.) and cost, A structure of a retardation film containing a cellulose ester resin was examined.

Further, in order to improve the adhesion between the polarizer of the thin film polarizer and the protective film to increase the strength of the polarizer, a method of joining the polarizer and the protective film via the active ray curable adhesive has been studied.

However, when the liquid crystal display device is moved and installed under a low-temperature and low-humidity atmosphere in a high-temperature and high-humidity atmosphere to observe the display screen from the viewing side of the polarizing plate, the thin film polarizer plate constituting the acrylic film / polarizer / It has been found that there is a problem that unevenness occurs. This is because the speed of change of the dimensional changes of the two protective films in a short period of time immediately after the abrupt change of the environment of the temperature and humidity of the environment is different from each other and the polarizer is sandwiched between the two protective films and the adhesive portion, It was presumed to be caused by the unevenness of the person.

Therefore, the present invention is not limited to the use of a protective film in which the dimensional change after a relatively long period of time such as day and night is adjusted under a specific environment as in the prior art, It is possible to obtain a polarizing plate in which display unevenness of the liquid crystal panel and deterioration of the polarizer adhesion are not exhibited even when the temperature and humidity environment of the use environment changes, by using a specific film adjusted to coincide the rate of change within a specific range as a protective film of the thin film polarizing plate And has reached the present invention.

[Measurement of rate of dimensional change of film]

The rate of dimensional change of film A and film B according to the present invention in a relatively short period of time immediately after a sudden change in the temperature and humidity environment of the environment is measured by the following method.

[1] Fig. 6 shows a schematic view of the film when measuring the specific L ₀ MD and L ₀ TD.

Two pieces of the film A and the film B are taken in a 10 cm square direction so that one side is parallel to the TD direction or the MD direction, and is used for measurement of the dimensional change in the MD direction or the TD direction. The film was cross-wound with a razor blade to a distance of 8 cm, and then placed in a constant temperature and humidity chamber at 23 ° C and 55% RH for 24 hours.

The humidity-adjusted film was placed on a stage of a microscope, and a glass plate was placed thereon, and the specimens (8 cm) were precisely measured with a microscope in the MD direction and the TD direction, and they were referred to as L ₀ MD and L ₀ TD, respectively.

The microscope used was a Nikon MEASURESCOPE MM-11 (eyepiece: x 10 objective lens: x 3) manufactured by Nikon Corporation, a data measuring device was directly connected to a microscope using a Nikon DP-302 DATA PROCESSOR, Output to software.

[2] The film was allowed to stand in a constant temperature and humidity bath at 80 ° C and 90% RH for 1 hour and then moved under a 23 ° C. and 55% RH temperature and humidity environment. Immediately after 1 minute, after 5 minutes, the MD direction and in TD direction, respectively, measured by the microscope and a data measuring instrument, each of _{L 1 MD ', L 1 TD} ', L 5 MD ', L 5 TD', L 30 MD ', and L ₃₀ TD' La do.

[3] To each of the dimensions obtained in [1] and [2] (wherein a) - by substituting the equation (f), after one minute, to obtain a rate of dimensional change of the film after 5 minutes and 30 minutes, and L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD.

Dimensional change rate after 1 minute

(Formula 1) L ₁ MD (%) = (L ₁ MD '- L ₀ MD) / L ₀ MD × 100

(Expression b) L ₁ TD (%) = (L ₁ TD'-L ₀ TD) / L ₀ TD × 100

Dimensional change rate after 5 minutes

(C) L ₅ MD (%) = (L ₅ MD'-L ₀ MD) / L ₀ MD x 100

(Formula d) L ₅ TD (%) = (L ₅ TD'-L ₀ TD) / L ₀ TD x 100

Dimensional change rate after 30 minutes

L ₃₀ MD (%) = (L ₃₀ MD'-L ₀ MD) / L ₀ MD x 100

(Formula f) L ₃₀ TD (%) = (L ₃₀ TD'-L ₀ TD) / L ₀ TD x 100

The films A and B according to the present invention are characterized by being an acrylic film and a cellulose acetate film satisfying the following (1) to (4). That is, by satisfying the conditions (1) and (2), it is possible to prevent the dimensional fluctuation in the MD direction and the TD direction, which fluctuate relatively largely after 5 minutes from immediately after (1 minute after) A and film B, it is possible to suppress the distortion between the protective film and the adhesive portion due to the difference in dimensional variation between them, and by satisfying (3) and (4) To stabilize the effect at

(1) 0.03 (%)? L ₁ MD-L ₅ MD? 0.30 (%)

(2) 0.03 (%)? L ₁ TD-L ₅ TD? 0.30 (%)

(3) 0 (%)? L ₅ MD-L ₃₀ MD? 0.10 (%)

(4) 0 (%)? L ₅ TD-L ₃₀ TD? 0.10 (%)

The films A and B according to the present invention are preferably an acrylic film and a cellulose acetate film satisfying the following (5) to (8).

(5) 0.05 (%)? L ₁ MD-L ₅ MD? 0.15 (%)

(6) 0.05 (%)? L ₁ TD-L ₅ TD? 0.15 (%)

(7) 0 (%)? L ₅ MD-L ₃₀ MD? 0.05 (%)

(8) 0 (%)? L ₅ TD-L ₃₀ TD? 0.05 (%)

The L ₃₀ TD and the L ₃₀ MD of the film A and the film B are within the range of -0.10 to 0.10%, respectively. Even when the environment of the temperature and humidity changes abruptly, the display unevenness of the liquid crystal panel and the polarizer In view of further improving durability against deterioration of adhesion to the substrate.

The means for adjusting the initial rate of dimensional change of the film A and the film B according to the present invention within the range indicated by the above items (1) to (8) is not particularly limited, but it is possible to adjust them by appropriately employing the following means Do.

The means for adjusting the rate of dimensional change of the film A according to the present invention within the range indicated by the above items (1) to (8) is not limited to the following ones, but may be suitably selected depending on the kind of acrylic resin and the weight average molecular weight, (Drying zone), the web is dried at a temperature of 50 to 100 占 폚 / sec or less after completion of the drying step (dryer zone) in the web drying step, in addition to the adjustment of the stretching direction and the stretching magnification, It is preferable to form a film by applying a cooling process for cooling the web at a speed within the range.

It is also preferable that the film A is a film having a laminated structure in which at least three layers each having a skin layer on both sides of the core layer and the core layer contains an acrylic resin and the skin layer contains a cellulose ester, It is possible to make the film A more easily controllable within the range of dimensional changes represented by the above-mentioned formulas (1) to (8), which is preferable.

Also, the use of acrylic resin and cellulose ester as a thermoplastic resin can also synergistically make use of the properties of other types of resins, so that the film A can be obtained within a range of dimensional changes represented by the above formulas (1) to (8) It is preferable to control it more easily.

The means for adjusting the rate of dimensional change of the film B according to the present invention within the range indicated by the above items (1) to (8) is not limited to the following, but may be suitably selected depending on the choice of the acetyl group substitution degree and the weight average molecular weight of the cellulose acetate, In addition to adjusting the type and amount, adjusting the stretching direction and the stretching magnification, and adjusting the film thickness, the details will be described later. In the step of drying the web, in the dryer zone within the range of 130 to 150 ° C, And a bending step of bending the B side opposite to the A side of the web alternately so as to be inward, wherein the bending step has a value of 1 / a when the radius when the web is bent is a (mm) It is preferable to form the film by repeating the bending process within a range of 0.035 mm ^-1 to 0.050 mm ^-1 and repeating the bending process 50 times or more and less than 120 times so that the molecular chain state of the film is made denser, The shrinkage ratio of the water-containing film can be effectively controlled.

The film B contains at least three layers each having a skin layer on both sides of the core layer. The core layer contains cellulose acetate having an acetyl group degree of substitution in the range of 2.0 to 2.45, and the skin layer has an acetyl group The film having a laminated structure containing cellulose acetate having a degree of substitution in the range of 2.6 to 2.95 can be easily adjusted within the dimensional change range expressed by the above formulas (1) to (4) .

5 is a schematic diagram showing the dimensional change of the film B (modified diacetyl cellulose film) according to the present invention.

It is made possible to approximate the behavior of the dimensional change for a short time immediately after the environment change of the diacetyl cellulose film to the behavior of the dimensional change of the acrylic film shown in Fig. Also, from the comparison with the embodiment, it was found that the behavior of the velocity of the dimensional change, not the absolute value of the dimensional change itself, is a factor affecting the display irregularity.

Hereinafter, constituent contents and manufacturing methods of the film A and the film B will be described in order.

«Film A: Acrylic Film»

The film A according to the present invention is characterized by being an acrylic film having a total film thickness within a range of 20 to 60 탆. By making the film thickness within the range, it is possible to exhibit the effect of the present invention, It is possible to provide a polarizing plate having a good thin film property. More preferably in the range of 20 to 40 mu m.

[Acrylic resin]

The film A according to the present invention is a film containing an acrylic resin. In the present invention, the acrylic resin is a polymer of an acrylate ester or methacrylate ester, and also includes a copolymer with other monomers.

Therefore, the acrylic resin used in the present invention also includes methacrylic resin. The resin is not particularly limited, but it preferably contains within the range of 50 to 99 mass% of methyl methacrylate units and the copolymerizable monomer thereof in an amount of 1 to 50 mass% of other monomer units.

Examples of other units constituting the acrylic resin formed by copolymerization include alkyl methacrylates having an alkyl number of 2 to 18, alkyl acrylates having an alkyl number of 1 to 18, methacrylic acid isobornyl, 2- Hydroxyalkyl acrylates such as hydroxyethyl acrylate, acrylamides such as?,? - unsaturated acids such as acrylic acid and methacrylic acid, acryloylmorpholine and N-hydroxyphenylmethacrylamide, N-vinylpyrrolidone Aromatic vinyl compounds such as monovalent carboxylic acids containing unsaturated groups such as maleic acid, fumaric acid and itaconic acid, styrene and? -Methylstyrene,?,? -Unsaturated nitriles such as acrylonitrile and methacrylonitrile, Maleic acid, maleimide, N-substituted maleimide, glutarimide, and glutaric anhydride.

As the copolymerizable monomer forming the unit excluding the glutarimide and the glutaric anhydride from the above unit, the monomer corresponding to the above unit may be mentioned. Specifically, alkyl methacrylates having 2 to 18 carbon atoms in the alkyl number, alkyl acrylates having 1 to 18 carbon atoms in the alkyl number, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate such as methacrylic acid isobornyl Acrylic acid such as acrylic acid, methacrylic acid and the like, acrylamide such as?,? - unsaturated acid, acryloylmorpholine, N-hydroxyphenylmethacrylamide and the like, unsaturated carboxylic acids such as N-vinylpyrrolidone, maleic acid, fumaric acid and itaconic acid Aromatic vinyl compounds such as styrene-containing dicarboxylic acids, styrene and? -Methylstyrene,?,? - unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide and N-substituted maleimide ≪ / RTI >

The glutarimide unit can be formed, for example, by reacting an intermediate polymer having a (meth) acrylate unit with a primary amine (imidizing agent) to imidize (Japanese Patent Application Laid-Open No. H11-26563 Reference).

The glutaric anhydride unit can be formed, for example, by heating an intermediate polymer having a (meth) acrylate unit (see Japanese Patent No. 4961164).

In the acrylic resin used in the present invention, among the above-mentioned structural units, from the viewpoint of mechanical properties, it is preferable to use acrylic acid such as methaboric acid, Particularly preferred are those comprising hydroxyethyl methacrylate, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride or glutarimide.

As the acrylic resin used in the present invention, an acrylic resin having a lactone ring structure in the structure is preferably used from the viewpoints of high heat resistance and high transparency. As the acrylic resin having a lactone ring structure, for example, Japanese Patent Application Laid-Open Nos. 2000-230016, 2001-151814, 2002-120326, 2002-254544 (Meth) acrylic copolymers having a lactone ring structure as disclosed in JP-A-2005-146084 and JP-A-2009-157352. (Meth) acryl-based resin having a lactone ring structure in which R ¹ is a hydrogen atom and R ² and R ³ are methyl groups, which is described in JP-A-2009-157352 Mass ratio: methyl methacrylate / 2- (hydroxymethyl) methyl acrylate = 8/2; lactone conversion rate: about 100%] can be preferably used.

The acrylic resin used in the film A according to the present invention is used in view of controlling the dimensional change with respect to the change of the environment of the temperature and humidity of the use environment, the peeling property from the metal support at the time of film production, the drying property of the organic solvent, From the viewpoint of improving the characteristics, the weight average molecular weight (Mw) is preferably within the range of 80,000 to 2,000,000, more preferably within the range of 90,000 to 1,000,000, and particularly preferably within the range of 100,000 to 500,000.

If it is 80,000 or more, heat resistance and mechanical properties are excellent. If it is 2,000,000 or less, the peelability from the metal support and the dryness of the organic solvent are excellent. If it is 80,000 or more, heat resistance and mechanical properties are excellent, and if it is 500,000 or less, the peelability from the metal support and the dryness of the organic solvent are excellent.

The weight average molecular weight of the acrylic resin used in the present invention can be measured by gel permeation chromatography. The measurement conditions are as follows.

Solvent: methylene chloride

Column: Shodex K806, K805, K803G (connected by using three connections made by Showa Denko K.K.)

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

Calibration curve: Standard polystyrene STK standard A calibration curve with 13 samples within the range of Mw = 500 to 2800000 (polystyrene manufactured by Tosoh Corporation) was used. The 13 samples are preferably used at substantially equal intervals.

The method for producing the acrylic resin used in the present invention is not particularly limited, and any of known methods such as suspension polymerization, emulsion polymerization, bulk polymerization or solution polymerization may be used. Here, as the polymerization initiator, a conventional peroxide-based or azo-based one may be used, or a redox-based one may be used. The polymerization temperature may be in the range of 30 to 100 占 폚 in suspension or emulsion polymerization and in the range of 80 to 160 占 폚 in mass or solution polymerization. In order to control the reduced viscosity of the obtained copolymer, polymerization may also be carried out using alkylmercaptan or the like as a chain transfer agent.

As the acrylic resin used in the present invention, commercially available acrylic resins can also be used. For example, Delpet (60N, 80N, 980N, SR8200, manufactured by Asahi Kasei Chemicals Co., Ltd.), DAIANAL BR52, BR80, BR83, BR85, BR88, EMB-143, EMB-159, EMB- EMB-161, EMB-218, EMB-229, EMB-270, EMB-273 (manufactured by Mitsubishi Rayon Co., Ltd.), KT75, TX400S and IPX012 (manufactured by Denki Kagaku Kogyo Co., Two or more acrylic resins may be used in combination.

The acrylic resin is a polymer obtained by polymerizing one or more monomers containing an acrylic ester monomer, and a copolymer of a plurality of kinds of monomers is preferable in view of optical properties, heat resistance and mechanical properties. The film A according to the present invention may contain additives other than acrylic resin, but it is preferable that the acrylic resin is contained in the range of 80 to 100 mass% with respect to the film in terms of optical properties, heat resistance, mechanical properties and cost .

As an example of the additive, the acrylic particles (D) described in International Publication WO20020001668 may contain the mechanical strength of the film in order to adjust the rate of dimensional change. Examples of commercially available products of such a multi-layered acrylic granular composite include "Metablen W-341" manufactured by Mitsubishi Rayon Co., "Kanase" manufactured by Kaneka Corporation, "Paraloid" manufactured by Kureha Corporation, (Trademark) manufactured by Kanto Kasei Kogyo Co., Ltd., "Acrylyloid" manufactured by Kanto Kasei Kogyo Co., Ltd., "Staphyloid" manufactured by Gansu Kasei Corporation, "KEMIS Snow MR-2G" These may be used alone or in combination of two or more.

As other additives, it is also preferable to contain additives such as plasticizers, ultraviolet absorbers, antioxidants, deterioration inhibitors, exfoliation aids, surfactants, dyes and fine particles, which will be described later.

In particular, it is preferable to contain the following sugar ester or polycondensation ester.

[Sugar ester]

In the acrylic film as the film A according to the present invention, it is preferable to contain a sugar ester other than the cellulose ester from the viewpoint of controlling the behavior of the dimensional change.

The sugar ester according to the present invention is preferably a sugar ester having at least one of a pyranose ring or a furanose ring having at least one and no more than 12 OH groups in its structure and esterifying all or a part of its OH groups.

The sugar ester according to the present invention is a compound containing at least any one of a furanose ring and a pyranose ring, and may be a monosaccharide or a polysaccharide having 2 to 12 sugar structures. The sugar ester is preferably a compound obtained by esterifying at least one OH group of the sugar structure. In the sugar ester according to the present invention, the average degree of ester substitution is preferably in the range of 4.0 to 8.0, more preferably in the range of 5.0 to 7.5.

Examples of sugar esters applicable to the present invention include sugar esters represented by the following formula (A) without particular limitation.

(A)

_{(HO) m -G- (OC (} = O) -R 2) n

In the above formula (A), G represents a residue of a monosaccharide or a disaccharide, R ² represents an aliphatic group or an aromatic group, m is the total number of hydroxyl groups directly bonded to a residue of a monosaccharide or a disaccharide, n Is the sum of the numbers of - (OC (= O) -R ² ) groups directly bonded to a residue of a monosaccharide or a disaccharide, and ³ ? M + n? 8 and n?

The sugar ester having the structure represented by the formula (A) is difficult to be isolated as a single kind of compound in which the number of hydroxy groups (m) and the number of - (OC (= O) -R ² ) groups (n) , And m and n in the formula are mixed with several kinds of different components. Therefore, the performance as a mixture in which the number of hydroxy groups (m) and the number of - (OC (= O) -R ² ) groups (n) are respectively changed is important. In the case of the protective film according to the present invention, , And sugar esters within the range of 5.0 to 7.5 are preferred.

In the above formula (A), G represents a residue of a monosaccharide or a disaccharide. Specific examples of monosaccharides include, for example, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose and ricin.

Specific examples of the compound having a monosaccharide residue of the sugar ester represented by the formula (A) are shown below, but the present invention is not limited to these exemplified compounds.

Specific examples of the disaccharide moiety include, for example, trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, isotrehalose and the like.

Specific examples of the compound having a disaccharide residue of a sugar ester represented by the formula (A) are shown below, but the present invention is not limited to these exemplified compounds.

In the formula (A), R ² represents an aliphatic group or an aromatic group. Here, the aliphatic group and the aromatic group may each independently have a substituent.

In the formula (A), m is the sum of the number of hydroxyl groups directly bonded to the monosaccharide or disaccharide residue, and n is - (OC (= O) -R ² ) the total number of groups. It is necessary that 3? M + n? 8 and 4? M + n? 8 be desirable. Also, n? 0. When n is 2 or more, the - (OC (= O) -R ² ) groups may be the same or different.

The aliphatic group in the definition of R ² may be linear, branched or cyclic, preferably 1 to 25 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 2 to 15 carbon atoms. Specific examples of the aliphatic group include linear or branched aliphatic groups such as methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, iso-butyl, Cyclohexyl, n-heptyl, n-octyl, bicyclooctyl, adamantyl, n-decyl, tert-octyl, dodecyl, hexadecyl, octadecyl and didecyl.

The aromatic group in the definition of R ² may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably 6 to 12 carbon atoms. Specific examples of the aromatic hydrocarbon group include rings of benzene, naphthalene, anthracene, biphenyl, terphenyl, and the like. As the aromatic hydrocarbon group, a benzene ring, a naphthalene ring and a biphenyl ring are particularly preferable. As the aromatic heterocyclic group, a ring containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom is preferable. Specific examples of the heterocycle include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, Wherein the benzene ring is selected from the group consisting of benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, phenylene ring, Benzooxazole, benzthiazole, benzotriazole, tetrazaine, and the like. As the aromatic heterocyclic group, a pyridine ring, a triazine ring, and a quinoline ring are particularly preferable.

Next, preferable examples of the sugar ester represented by the formula (A) are shown below, but the present invention is not limited to these exemplified compounds.

The sugar ester may contain two or more different substituent groups in one molecule and may contain two or more different aromatic substituent groups in one molecule and may contain two or more different aliphatic substituent groups May be contained in one molecule.

It is also preferable that two or more kinds of sugar esters are mixed and contained. It is also preferable that both the sugar ester containing an aromatic substituent and the sugar ester containing an aliphatic substituent are contained at the same time.

≪ Synthesis Example: Synthesis Example of a sugar ester represented by the formula (A) >

The following is an example of the synthesis of a sugar ester suitable for use in the present invention.

34.2 g (0.1 mol) of sucrose, 180.8 g (0.8 mol) of anhydrous benzoic acid and 379.7 g (4.8 mol) of pyridine were fed into a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas- , The temperature was elevated while nitrogen gas was bubbled through the nitrogen gas introducing tube under stirring, and the esterification reaction was carried out at 70 ° C for 5 hours. Subsequently, the inside of the flask was reduced to 4 × 10 ² Pa or less, excess pyridine was distilled off at 60 ° C., the pressure in the flask was reduced to 1.3 × 10 5 Pa or less, and the temperature was raised to 120 ° C. to obtain an anhydrous benzoic acid Most were distilled off. Subsequently, 1 L of toluene and 300 g of a 0.5 mass% aqueous solution of sodium carbonate were added, stirred at 50 캜 for 30 minutes, and then allowed to stand to separate the toluene layer. Finally, 100 g of water was added to the separated toluene layer, and the mixture was rinsed at room temperature for 30 minutes. Then, the toluene layer was collected, and toluene was distilled off at 60 캜 under reduced pressure (4 x 10 ² Pa or less) -1, A-2, A-3, A-4 and A-5. Analysis of the obtained mixture by HPLC and LC-MASS showed that 7 mass% of A-1, 58 mass% of A-2, 23 mass% of A-3, 9 mass% of A- Mass%, and the average ester substitution degree of the sugar ester was 6.57. Further, a part of the obtained mixture was purified by silica gel column chromatography to obtain A-1, A-2, A-3, A-4 and A-5 having a purity of 100%.

The amount of the sugar ester added is preferably in the range of 0.1 to 20 mass%, more preferably in the range of 1 to 15 mass%, based on the acrylic resin.

Further, the film A according to the present invention preferably contains the following ester (polycondensation ester).

[Polycondensation ester]

In the film A according to the present invention, it is preferable to use an ester other than the sugar ester as one of the plasticizers.

The ester other than the sugar ester applicable to the present invention is not particularly limited, but it is preferable to use a polycondensation ester having a structure represented by the following formula (1).

The polycondensation ester is preferably contained in the range of 1 to 20 mass% in the film A according to the present invention, more preferably in the range of 2 to 15 mass% .

(1)

In the above formula (1), B ₃ and B ₄ each independently represent an aliphatic or aromatic monocarboxylic acid residue or a hydroxy group. G ₂ represents an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms. A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms. n represents an integer of 1 or more.

In the present invention, the polycondensation ester is a polycondensation ester containing a repeating unit obtained by reacting a dicarboxylic acid with a diol, A represents a carboxylic acid residue in the polycondensation ester, and G ₂ represents an alcohol residue.

The dicarboxylic acid constituting the polycondensation ester is an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid, preferably an aromatic dicarboxylic acid. The dicarboxylic acid may be one kind or a mixture of two or more kinds. Particularly, it is preferable to mix aromatic and aliphatic.

The diol constituting the polycondensation ester is an aromatic diol, an aliphatic diol or an alicyclic diol, preferably an aliphatic diol, more preferably a diol having 1 to 8 carbon atoms. The diol may be one kind or a mixture of two or more kinds.

Among them, it is preferable to include a repeating unit obtained by reacting at least a dicarboxylic acid containing an aromatic dicarboxylic acid with a diol having a carbon number of 1 to 8, and it is preferable to contain a repeating unit obtained by reacting an aromatic dicarboxylic acid with an aromatic dicarboxylic acid More preferably a repeating unit obtained by reacting a carboxylic acid with a diol having 1 to 8 carbon atoms.

Both ends of the molecule of the polycondensation ester may be sealed or not sealed.

Specific examples of the alkylene dicarboxylic acid constituting A in the formula (1) include 1,2-ethanedicarboxylic acid (succinic acid, 1,3-propanedicarboxylic acid (glutaric acid, 1,4-butane Dicarboxylic acid (including divalent groups derived from adipic acid, 1,5-pentanedicarboxylic acid (pimelic acid, 1,8-octanedicarboxylic acid (sebacic acid), etc.) Specific examples of the nylenedicarboxylic acid include maleic acid and fumaric acid. Specific examples of the aryldicarboxylic acid constituting A include 1,2-benzenedicarboxylic acid (phthalic acid), 1,3-benzene Dicarboxylic acid, 1,4-benzenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid.

A may be one species, or two or more species may be combined. Among them, A is preferably a combination of an alkylene dicarboxylic acid having 4 to 12 carbon atoms and an aryl dicarboxylic acid having 8 to 12 carbon atoms.

G ₂ in the formula (1) represents a divalent group derived from an alkylene glycol having 2 to 12 carbon atoms, a divalent group derived from an aryl glycol having 6 to 12 carbon atoms, or a divalent group derived from an alkylene glycol having 4 to 12 carbon atoms And a divalent group derived from oxyalkylene glycol.

Examples of the divalent group derived from an alkylene glycol having 2 to 12 carbon atoms in G ₂ include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3 Butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2- ), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane) , 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, , 8-octanediol, 1,9-nonanediol, 1,10-decanediol and 1,12-octadecanediol, and the like.

Examples of the divalent group derived from an aryl glycol having 6 to 12 carbon atoms in G ₂ include 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol), 1,3- 1,4-dihydroxybenzene (hydroquinone), and the like. Examples of the divalent group derived from oxyalkylene glycol having 4 to 12 carbon atoms in G include divalent groups derived from diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and the like .

G ₂ may be one species, or two or more species may be combined. Among them, G ₂ is preferably a divalent group derived from an alkylene glycol having 2 to 12 carbon atoms, more preferably 2 to 5, and most preferably 2 to 4.

B ₃ and B ₄ in the formula (1) are each a monovalent group derived from an aromatic ring-containing monocarboxylic acid or an aliphatic monocarboxylic acid, or a hydroxy group.

The aromatic ring-containing monocarboxylic acid in the monovalent group derived from the aromatic ring-containing monocarboxylic acid is a carboxylic acid containing an aromatic ring in the molecule and not only the aromatic ring is directly bonded to the carboxyl group, And a carboxyl group. Examples of the monovalent group derived from an aromatic ring-containing monocarboxylic acid include benzoic acid, para-tert-butylbenzoic acid, orthotoluenic acid, meta-toluic acid, paratoluic acid, dimethylbenzoic acid, ethylbenzoic acid, And monovalent groups derived from acetoxybenzoic acid, phenylacetic acid, 3-phenylpropionic acid, and the like. Among them, benzoic acid and para-toluic acid are preferable.

Examples of the monovalent group derived from an aliphatic monocarboxylic acid include monovalent groups derived from acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid and the like. Among them, a monovalent group derived from an alkyl monocarboxylic acid having 1 to 3 carbon atoms in the alkyl moiety is preferable, and an acetyl group (monovalent group derived from acetic acid) is more preferable.

The weight average molecular weight of the polycondensate ester according to the present invention is preferably in the range of 500 to 3,000, more preferably in the range of 600 to 2,000. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

Specific examples of polycondensation esters having a structure represented by the formula (1) are shown below, but the present invention is not limited thereto.

Hereinafter, specific examples of synthesis of the polycondensation ester described above will be described.

<Polycondensation ester P1>

180 g of ethylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were put into a 2 L four-necked flask equipped with a thermometer, a stirrer and a full cooling tube, The temperature was gradually raised while stirring at 230 캜. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, unreacted ethylene glycol was distilled off under reduced pressure at 200 占 폚 to obtain a polycondensation ester P1. An acid value of 0.20, and a number average molecular weight of 450.

<Polycondensation ester P2>

251 g of 1,2-propylene glycol, 244 g of phthalic anhydride, 103 g of adipic acid, 610 g of benzoic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were put into a 2 L four-necked flask equipped with a thermometer, And the temperature was gradually raised while stirring in a nitrogen stream until the temperature reached 230 ° C. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 占 폚 to obtain a polycondensation ester P2. An acid value of 0.10 and a number average molecular weight of 450.

<Polycondensation ester P3>

330 g of 1,4-butanediol, 244 g of phthalic anhydride, 103 g of adipic acid, 610 g of benzoic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer, , And the temperature was gradually raised while stirring in a nitrogen stream until the temperature reached 230 deg. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, the unreacted 1,4-butanediol was distilled off under reduced pressure at 200 占 폚 to obtain a polycondensation ester P3. An acid value of 0.50 and a number average molecular weight of 2000.

<Polycondensation ester P4>

251 g of 1,2-propylene glycol, 354 g of terephthalic acid, 610 g of benzoic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer and a super cooling tube, Deg.] C while stirring. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 DEG C to obtain a polycondensation ester P4. An acid value of 0.10, and a number average molecular weight of 400.

<Polycondensation ester P5>

251 g of 1,2-propylene glycol, 354 g of terephthalic acid, 680 g of p-toluic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were placed in a 2 L four-necked flask equipped with a thermometer, The temperature is gradually raised with stirring until the temperature of the stream becomes 230 deg. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 占 폚 to obtain a polycondensation ester P5. An acid value of 0.30, and a number average molecular weight of 400.

<Polycondensation ester P6>

180 g of 1,2-propylene glycol, 292 g of adipic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were placed in a 2 L four-necked flask equipped with a thermometer, a stirrer and a cooling tube, The temperature is gradually raised while stirring to 200 ° C. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 占 폚 to obtain a polycondensation ester P6. An acid value of 0.10, and a number average molecular weight of 400.

<Polycondensation ester P7>

244 g of 1,2-propylene glycol, phthalic anhydride, 103 g of adipic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were placed in a 2 L four-necked flask equipped with a thermometer, a stirrer and a full cooling tube, The temperature is gradually raised in the nitrogen stream while stirring until the temperature becomes 200 캜. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 占 폚 to obtain a polycondensation ester P7. An acid value of 0.10 and a number average molecular weight of 320.

<Polycondensation ester P8>

251 g of ethylene glycol, 244 g of phthalic anhydride, 120 g of succinic acid, 150 g of acetic acid and 0.191 g of tetraisopropyl titanate as an esterification catalyst were placed in a 2 L four-necked flask equipped with a thermometer, Deg.] C while stirring. Dehydration condensation reaction was carried out while observing the polymerization degree. After completion of the reaction, unreacted ethylene glycol was distilled off under reduced pressure at 200 占 폚 to obtain a polycondensation ester P8. An acid value of 0.50, and a number average molecular weight of 1200.

[Laminated film: (TAC / acrylic / TAC) film]

Film A according to the present invention is a film having at least three layers each having a skin layer on both sides of a core layer, the core layer containing an acrylic resin, and the skin layer containing a cellulose ester, It is easy to control the dimensional change rate expressed by the above formulas (1) to (4) within a desired range by overlapping other types of resins.

In the present specification, the term &quot; core layer &quot; refers to a layer having the largest thickness among the layers of the film, and the term &quot; skin layer &quot; means a layer having a thickness smaller than that of the &quot; core layer &quot;. In the present invention, there is also a &quot; skin layer &quot; on the &quot; core layer &quot; side of the film having the laminated structure of the &quot; core layer &quot; May be the same or different in film thickness.

As the acrylic resin contained in the core layer, the above acrylic resin, additives and the like can be suitably used.

The cellulose ester contained in the skin layer is not particularly limited, but specific examples of the cellulose ester include cellulose (di (tri)) acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate and cellulose Phthalate, and cellulose triacetate having an acetyl group with an average degree of substitution in the range of 2.6 to 2.95 is excellent in adhesion to a polarizer, and distortion of a film and an adhesive portion due to dimensional change is suppressed It is particularly preferable from the viewpoint of reduction.

The core layer and the skin layer preferably contain an additive such as a plasticizer, an ultraviolet absorber, an antioxidant, a deterioration inhibitor, a stripping aid, a surfactant, a dye and a fine particle to be described later.

As a method for producing the film A according to the present invention, it is preferable that the film formation is simultaneous multi-layer flexible film formation, and it is preferable that the film is a shared loop to be described later.

The thickness of each layer is not particularly limited as long as the thickness of the skin layer is thinner than that of the core layer. Preferably, the thickness of the skin layer is 0.2 to 50% of the total thickness of the film A, Is preferably 2 to 30% in thickness. Since the total film thickness of the film A is in the range of 20 to 60 占 퐉, it is preferable that the film thickness of the core layer and the film thickness of the skin layer are adjusted within the above range.

[Film mixed with acrylic resin and cellulose ester]

In the film A according to the present invention, an acrylic resin and a cellulose ester may be mixed and used. In the case of mixing, the mixing ratio of the acrylic resin and the cellulose ester is preferably within the range of acrylic resin: cellulose ester = 95: 5 to 50:50, and preferably 90:10 to 70:30, It is more preferable from the viewpoint of controlling the behavior of the dimensional change.

The acrylic resin can be appropriately selected from the above-mentioned acrylic resins. As the cellulose ester, a resin contained in the skin layer may be used, or cellulose triacetate having an acetyl group average degree of substitution in the range of 2.6 to 2.95, or a total acyl group total substitution degree in the range of 2.0 to 2.9, Is 0.1 to 1.9, and the degree of substitution of the propionyl group is 1.1 to 2.8 is more preferably used, and it is particularly preferable to use the cellulose acetate propionate.

&Quot; Film B: cellulose acetate film &quot;

The film B according to the present invention is characterized by containing cellulose acetate having a film thickness in the range of 20 to 60 占 퐉 and an acetyl group average degree of substitution in the range of 2.0 to 2.5. The film thickness is more preferably in the range of 20 to 40 占 퐉. Within this range, sufficient strength and excellent handling properties can be obtained, and a polarizing plate of a thin film can be easily produced.

[Cellulose acetate]

The film B according to the present invention is characterized in that it comprises cellulose acetate having an acetyl group with an average degree of substitution in the range of 2.0 to 2.5 as a main component. The main component referred to in the present invention is cellulose acetate having a degree of substitution of cellulose acetate having an acetyl group in an average degree of substitution of 2.0 to 2.5 in the cellulose acetate constituting the cellulose acetate film in an amount of 60% by mass or more, preferably 80% by mass or more , And more preferably 95 mass% or more. The average degree of substitution of the acetyl group is preferably in the range of 2.1 to 2.4 because it is easy to control the behavior of the dimensional change and the degree of phase difference is high and is more preferable for use as a retardation film.

The average substitution degree of the acetyl group in the cellulose acetate can be determined by measuring in accordance with ASTM-D817-96.

In the present invention, when the average substitution degree of the acetyl group of the applied cellulose acetate is within the above range, the effect of the present invention is manifested, and the properties such as high suitability for film formation and excellent handling property as a film Can be realized.

The number average molecular weight (Mn) of the cellulose acetate is preferably in the range of 80000 to 155000, and more preferably in the range of 90000 to 152000. The weight average molecular weight (Mw) is preferably in the range of 120000 to 310000. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably in the range of 1.4 to 2.5, more preferably in the range of 1.5 to 2.0.

The average molecular weight (Mn, Mw) of the cellulose acetate can be measured by gel permeation chromatography. The measurement conditions are as described above.

The cellulose acetate according to the present invention can be produced by a conventional method such as a sulfuric acid catalyst method, an acetic acid method, a methylene chloride method and the like. The raw material is not particularly limited, but cotton linter, wood pulp (conifer- Derived from hardwoods), kenaf, and the like. And the cellulose acetate obtained from them may be mixed and used at an arbitrary ratio. Further, the cellulose acetate according to the present invention can be synthesized by referring to the methods described in, for example, Japanese Patent Laid-Open Nos. 10-45804 and 2005-281645.

(Sugar ester and polycondensation ester having a structure represented by the above formula (1))

The film B according to the present invention is preferable from the viewpoint of adjusting the speed of dimensional change such as the sugar ester or the polycondensation ester having the structure represented by the above-mentioned formula (1) as in the case of the film A.

The content of the sugar ester and the polycondensation ester in the film B is preferably within a range of 1 to 20 mass%, and more preferably within a range of 2 to 15 mass%.

[Other additives]

The films A and B according to the present invention preferably contain additives such as plasticizers, ultraviolet absorbers, antioxidants, deterioration inhibitors, release aids, surfactants, dyes and fine particles. Hereinafter, these additives will be described. It is preferable that the film A and the film B are suitably used by adjusting the kinds and amounts of the additives. Hereinafter, the films A and B are referred to as protective films.

(Polyhydric alcohol ester)

In the protective film according to the present invention, it is also preferable to contain a polyhydric alcohol ester represented by the following formula (2).

(2)

B ₁ -GB ₂

In the above formula (2), B ₁ and B ₂ each independently represent an aliphatic or aromatic monocarboxylic acid residue. G represents a linear or branched alkylene glycol residue having 2 to 12 carbon atoms.

In the formula (2), G represents a divalent group derived from a linear or branched alkylene glycol having 2 to 12 carbon atoms.

Examples of the divalent group derived from alkylene glycol having 2 to 12 carbon atoms in G include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3- 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) , 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 2,2- Methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, Hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol and 1,12-octadecanediol. The alkylene glycol may be used preferably in a mixture of two or more thereof.

In formula (2), B ₁ and B ₂ are each independently a monovalent group derived from an aromatic ring-containing monocarboxylic acid or an aliphatic monocarboxylic acid.

The aromatic ring-containing monocarboxylic acid in the monovalent group derived from the aromatic ring-containing monocarboxylic acid is a carboxylic acid containing an aromatic ring in the molecule and not only the aromatic ring is directly bonded to the carboxyl group, And a carboxyl group. Examples of the monovalent group derived from an aromatic ring-containing monocarboxylic acid include benzoic acid, para-tert-butylbenzoic acid, orthotoluenic acid, meta-toluic acid, paratoluic acid, dimethylbenzoic acid, ethylbenzoic acid, And monovalent groups derived from acetoxybenzoic acid, phenylacetic acid, 3-phenylpropionic acid, and the like. Among them, benzoic acid and para-toluic acid are preferable.

Examples of the monovalent group derived from an aliphatic monocarboxylic acid include monovalent groups derived from acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid and the like. Among them, a monovalent group derived from an alkyl monocarboxylic acid having 1 to 10 carbon atoms in the alkyl moiety is preferable, and an acetyl group (monovalent group derived from acetic acid) is more preferable.

Specific examples of polyhydric alcohol esters applicable to the present invention are shown below, but the present invention is not limited to these exemplified compounds.

The polyhydric alcohol ester having the structure represented by the formula (2) according to the present invention is preferably contained in the range of 0.5 to 5 mass%, more preferably 1 to 3 mass% , More preferably in the range of 1 to 2% by mass.

The polyhydric alcohol ester having the structure represented by the formula (2) according to the present invention can be synthesized according to a conventionally known general synthesis method.

(Phosphate ester)

The protective film according to the present invention may be a phosphate ester. Examples of the phosphoric ester include triaryl phosphoric acid ester, diaryl phosphoric acid ester, monoaryl phosphoric acid ester, aryl phosphonic acid compound, aryl phosphine oxide compound, condensed aryl phosphoric acid ester, halogenated alkyl phosphoric acid ester, halogen-containing condensed phosphoric acid ester, A phosphoric acid ester, and a halogen-containing phosphorous acid ester.

Specific examples of the phosphoric acid ester include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris (dichloropropyl) Phosphate, tris (tribromoneopentyl) phosphate, and the like.

(Esters of glycolic acid)

In the present invention, esters (glycolate compounds) of glycolic acid can be used as one kind of polyhydric alcohol esters.

The glycolate compound applicable to the present invention is not particularly limited, but alkyl phthalyl alkyl glycolates can be preferably used.

The alkyl phthalyl alkyl glycolates include, for example, methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octylphthalyl octyl glycolate, Ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octylphthalyl methyl glycolate, octylphthalyl ethyl glycolate, and the like, preferably ethyl phthalyl ethyl Glycolate.

(Ultraviolet absorber)

The protective film according to the present invention preferably contains an ultraviolet absorber from the viewpoint of improving the light resistance. The ultraviolet absorber is intended to improve the light resistance by absorbing ultraviolet rays of 400 nm or less. Particularly, the transmittance at a wavelength of 370 nm is preferably within a range of 2 to 30%, more preferably within a range of 4 to 20% , More preferably in the range of 5 to 10%.

The ultraviolet absorber preferably used in the present invention is a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, a triazine ultraviolet absorber, and particularly preferably a benzotriazole ultraviolet absorber and a benzophenone ultraviolet absorber.

Benzotriazole, (2-2H-benzotriazol-2-yl) -6- (3,5-di-sec- (Straight chain and branched dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone and the like, and also Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328 and Tinuvin 928, all of which are commercially available from BASF Japan, and can be preferably used. Among them, halogen-free is preferable.

In addition, a discotic compound such as a compound having a 1,3,5-triazine ring is also preferably used as an ultraviolet absorber.

The protective film according to the present invention preferably contains two or more ultraviolet absorbers.

As the ultraviolet absorber, a polymer ultraviolet absorber can be preferably used. In particular, a polymer-type ultraviolet absorber described in JP-A-6-148430 is preferably used. It is preferable that the ultraviolet absorber does not have a halogen group.

The ultraviolet absorber may be added by dissolving the ultraviolet absorber in an alcohol such as methanol, ethanol or butanol, or an organic solvent such as methylene chloride, methyl acetate, acetone, or dioxolane, or a mixed solvent thereof, Or may be added during the composition.

To dissolve in an organic solvent such as an inorganic powder, it is dispersed in an organic solvent and a cellulose ester (cellulose acetate) using a dissolver or a sand mill, and then added to the dope.

The amount of the ultraviolet absorber to be used is not uniform depending on the kind of the ultraviolet absorber and the conditions of use. When the dry film thickness of the protective film is in the range of 15 to 50 mu m, the amount is preferably in the range of 0.5 to 10 wt% , And more preferably in the range of 0.6 to 4 mass%.

(Antioxidant)

Antioxidants are also called deterioration inhibitors. When an organic electroluminescent display device or the like is placed in a state of high humidity and high temperature, deterioration of the protective film may occur.

The antioxidant has a role of delaying or preventing the decomposition of the protective film by, for example, halogen in the residual solvent amount in the protective film or phosphoric acid in the phosphoric acid-based plasticizer or the like, so that the antioxidant is contained in the protective film according to the present invention desirable.

As such an antioxidant, a hindered phenol-based compound is preferably used, and for example, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexane Di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4- Di-t-butyl anilino) -1,3,5-triazine, 2,2-thio-diethylene bis [3- (3,5- Propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5- (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5- Di-t-butyl-4-hydroxybenzyl) -isocyanurate and the like.

Particularly preferred are 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t- Glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferable. Also, hydrazine-based metal inactivators such as N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris -t-butylphenyl) phosphite, or the like may be used in combination.

The amount of these compounds to be added is preferably in the range of 1 ppm to 1.0%, more preferably in the range of 10 to 1000 ppm, in mass ratio with respect to the protective film.

(Fine particles (made of mat))

The protective film may further contain fine particles (made of a mat) if necessary in order to improve the slidability of the surface.

The fine particles may be inorganic fine particles or organic fine particles. Examples of the inorganic fine particles include silicon dioxide (silica), titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, And the like. Of these, silicon dioxide and zirconium oxide are preferable, and silicon dioxide is more preferable in order to reduce an increase in haze of the resulting film.

Examples of the fine particles of silicon dioxide include AEROSIL® R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600, NAX50 (manufactured by Nippon Aerosil Co., Ltd.), Shihosta KE-P10, KE -P30, KE-P50, and KE-P100 (manufactured by Nippon Shokubai Co., Ltd.). Above all, Aerosil R972V, NAX50, Sihosta KE-P30 and the like are particularly preferred because they reduce the coefficient of friction while keeping the turbidity of the obtained film low.

The primary particle diameter of the fine particles is preferably in the range of 5 to 50 nm, more preferably in the range of 7 to 20 nm. If the primary particle diameter is large, the effect of increasing the slidability of the obtained film is large, but the transparency tends to decrease. Therefore, the fine particles may be contained as a secondary aggregate within a particle diameter of 0.05 to 0.3 탆. The size of the primary particles or the secondary aggregates of the fine particles can be measured by observing primary particles or secondary aggregates within a range of 50 to 200,000 times magnification with a transmission electron microscope to determine the primary particle or secondary aggregate Can be obtained as an average value.

The content of the fine particles is preferably in the range of 0.05 to 1.0 mass%, more preferably in the range of 0.1 to 0.8 mass% with respect to the resin forming the protective film.

[Film of laminated structure: (TAC / DAC / TAC) film]

Film B according to the present invention also includes diacetylcellulose (DAC) having at least three layers each having a skin layer on both sides of the core layer and having the acetyl group substitution degree in the range of 2.0 to 2.45, (TAC) having an acetyl group substitution degree in a range of 2.60 to 2.95, and the film layer is a film having a laminated structure containing triacetyl cellulose (TAC) having an acetyl group substitution degree within a range of 2.60 to 2.95. ) Can be easily controlled within a desired range.

The average degree of substitution of the acetyl group of the triacetyl cellulose contained in the skin layer is preferably 2.6 or more, which is particularly preferable from the viewpoint of reducing the occurrence of distortion of the film and the adhesive portion due to dimensional changes.

It is preferable that the core layer and the skin layer suitably contain additives such as the above plasticizer, ultraviolet absorber, antioxidant, deterioration inhibitor, release aid, surfactant, dye and fine particles.

The cellulose acetate film according to the present invention is not particularly limited as long as the thickness of the skin layer is thinner than that of the core layer. Preferably, the skin layer is within the range of 0.2 to 50% of the total thickness of the film B, It is preferable that the thickness is in the range of 2 to 30%. Since the total film thickness of the film B is in the range of 20 to 60 占 퐉, it is preferable that the film thickness of the core layer and the film thickness of the skin layer are adjusted within the above range.

&Lt; Production method of film A and film B &

As the production method of the acrylic film as the film A and the cellulose acetate film as the film B according to the present invention, a production method such as a general inflation method, a T-die method, a calendar method, a cutting method, a fusing method, an emulsion method, From the viewpoints of suppression of coloration, suppression of foreign matter defects, suppression of optical defects such as die lines, etc., the solution casting method and the melt casting method can be selected as the film forming method. Particularly, It is preferable from the viewpoint of obtaining a smooth surface.

[Solution flexible film-forming method]

Hereinafter, a production example of producing the protective film according to the present invention by the solution casting method will be described.

As a method of producing the protective film according to the present invention, it is possible to use a manufacturing method such as a general inflation method, a T-die method, a calendering method, a cutting method, a soft method, an emulsion method and a hot press method. In view of the suppression of optical defects such as suppression and die line, the film forming method can be selected from a solution casting film forming method and a melt casting film forming method, and is preferably a solution casting method.

The production of the protective film according to the present invention can be carried out by a process comprising the steps of preparing a dope by dissolving additives such as an acrylic resin, a cellulose ester and the plasticizer in a solvent, a step of softening the dope on a belt- A step of drying as a web, a step of peeling from a metal support, a step of stretching, a step of drying, and a step of winding after cooling. The protective film of the present invention preferably contains an acrylic resin or a cellulose acetate in a solid content within a range of 60 to 95 mass%.

Here, the film forming method of the cellulose acetate film as the film B is described as an example, and the same method can be applied to the manufacturing method of the acrylic film as the film A. In the following description, particularly regarding the manufacturing method relating to an acrylic film, an explanation is appropriately added as an acrylic film.

(1) Dissolution Process

The cellulose acetate and optionally the sugar ester, polycondensation ester, polyhydric alcohol ester or other compound according to the present invention are dissolved in an organic solvent mainly composed of a good solvent for the cellulose acetate in a dissolving oven while stirring to form a dope Or a solution of a sugar ester, a polycondensation ester, a polyhydric alcohol ester or other compound according to the present invention is mixed with the cellulose acetate solution to form a dope as a main solution.

When the cellulose acetate film according to the present invention is prepared by the solution casting method, the organic solvent useful for forming the dope can be used without limitation as long as it dissolves cellulose acetate and other compounds at the same time.

Examples of the chlorinated organic solvent include methylene chloride and examples of the non-chlorinated organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, , Ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3 , 3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro Propanol, nitroethane and the like, and methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

The dope preferably contains, in addition to the organic solvent, a linear or branched aliphatic alcohol having 1 to 4 carbon atoms in the range of 1 to 40 mass%. When the proportion of alcohol in the dope is high, the web gels to facilitate separation from the metal support. When the proportion of alcohol is small, it also promotes dissolution of cellulose acetate and other compounds in the non-chlorinated organic solvent system . In the formation of the cellulose acetate film according to the present invention, a method of forming a film by using a dope in which the alcohol concentration is in the range of 0.5 to 15.0 mass% can be applied in order to enhance the planarity of the obtained cellulose acetate film.

In particular, it is preferable that the dope composition is obtained by dissolving cellulose acetate and other compounds in a total amount of 15 to 45 mass% in a solvent containing methylene chloride and a straight chain or branched aliphatic alcohol having 1 to 4 carbon atoms.

Examples of the straight chain or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol. Of these, methanol and ethanol are preferable in view of stability of the dope, relatively low boiling point, good drying property, and the like.

The dissolution of cellulose acetate and sugar esters, polycondensation esters, polyhydric alcohol esters, or other compounds can be carried out at atmospheric pressure, at a temperature lower than the boiling point of the main solvent, or under pressure at a boiling point or more of the main solvent, 9-95544, Japanese Patent Application Laid-Open No. 9-95557, or Japanese Patent Application Laid-Open No. 9-95538, a method in which a high-pressure method described in JP-A-11-21379 . In particular, a method of carrying out pressurization at a boiling point or higher of the main solvent is preferable.

The concentration of the cellulose acetate in the dope is preferably in the range of 10 to 40 mass%. A compound is added to the dope during or after dissolution, dissolved and dispersed, filtered with a filter, defoamed, and sent to the next process with a liquid-feeding pump.

The filtration is preferably performed using a filter material having a collection particle diameter within a range of 0.5 to 5 μm and a filtration time within a range of 10 to 25 sec / 100 ml.

In this method, the aggregate remaining at the time of particle dispersion or the aggregate generated at the time of addition of the main dope is used only in the range of 0.5 to 5 mu m in diameter and in the filtration material in the range of 10 to 25 sec / Can be removed. In the main dope, since the concentration of the particles is sufficiently lighter than that of the additive liquid, the aggregates stick to each other at the time of filtration and do not cause a rapid increase in the filtration pressure.

7 is a diagram schematically showing an example of a dope producing step, a softening step and a drying step of a preferable solution softening film-forming method of the present invention.

The large agglomerate is removed from the charging kiln 41 by the filter 44, and is sent to the stock kiln 42. Thereafter, various additive liquids are added from the stock kiln 42 to the main dope melting furnace 1.

Thereafter, the main dope is filtered with the main filter 3, and the ultraviolet absorbent added liquid is added inline from the line 16 to the main filter.

In many cases, the main dope may contain about 10 to 50 mass% of the recyclable material.

The recyclable material is a cellulose acetate film finely pulverized. The cellulose acylate film used in the production of a cellulose acetate film is cut out on both sides of the film, or a cellulose acetate film fabric exceeding a specified value of the film due to scratching or the like is used do.

As the raw material of the resin used in the preparation of the dope, pellets of cellulose acetate and other compounds may be preferably used.

(2) Flexible process

(2-1) Dope flexing

An endless metal support 31 for feeding the dope to the pressurizing die 30 through a feed pump (for example, a pressurized metering gear pump) and infinitely feeding it, for example, a stainless steel belt or a rotating metal drum In a flexible position on a metal support of a press die slit.

The metal support in the casting step is preferably mirror-finished on the surface, and as the metal support, a stainless steel belt or a drum finished by plating the cast iron surface is preferably used. The width of the cast can be in the range of 1 to 4 m, preferably in the range of 1.5 to 3 m, more preferably in the range of 2 to 2.8 m. The surface temperature of the metal support of the flexible process is set within a range of -50 ° C to a temperature at which the solvent does not foam by boiling, more preferably within a range of -30 to 100 ° C. A high temperature is preferable because it can speed up the drying speed of the web. However, if the temperature is too high, the web may be foamed or the planarity may deteriorate. The preferred support temperature is appropriately determined within the range of 0 to 100 占 폚, more preferably in the range of 5 to 30 占 폚. Alternatively, it is preferable that the web be gelled by cooling to peel off the drum in a state containing a large amount of residual solvent. A method of controlling the temperature of the metal support is not particularly limited, but there is a method of spraying warm air or cold air with extreme pressure, or a method of bringing warm water into contact with the metal support. Use of hot water is preferable because heat is efficiently transferred and the time until the temperature of the metal support becomes constant is short. In the case of using hot wind, in consideration of the temperature drop of the web due to the latent heat of evaporation of the solvent, the hot wind above the boiling point of the solvent is used, while the foaming is also prevented, and the wind at a temperature higher than the desired temperature is sometimes used. Particularly, it is preferable to change the temperature of the support and the temperature of the drying wind during the period from the time of pouring to the time of peeling, thereby efficiently performing drying.

It is preferable to use a press die which can adjust the slit shape of the crotch member portion of the die and make the film thickness uniform. The pressure die includes a coated hanger die and a T die, all of which are preferably used. The surface of the metal support is mirror-finished. Two or more pressure dies may be provided on the metal support in order to increase the film forming speed and the doping amount may be divided into two or more layers.

(2-2) Shared year

The film of the laminated structure such as the (TAC / acrylic / TAC) film and the (TAC / DAC / TAC) film according to the present invention can be obtained by using a dope containing an acrylic resin and a dope containing a cellulose ester, It is possible to form two or more kinds of dope in a flexible manner on a smooth band or drum.

Two or more kinds of dope may be simultaneously poured on a support, or they may be separately poured on a support. In the case of the sequential softening method which is separately flexible, the dope on the support side can be firstly softened and dried to some extent on the support, and thereafter laid over and softened. Further, when three or more kinds of dope are used, it is also possible to produce a film of a laminated structure by flexibly combining a simultaneous softening (also referred to as a shearing softening) and a sequential softening properly. These methods of forming by co-firing or sequential fusing are different from the method of applying on a dried film in that the boundaries of the respective layers of the lamination structure become unclear and the lamination structure is not clearly distinguished There is an effect of improving the adhesion between the respective layers.

The production method in the case of using the film A and the film B according to the present invention as the film of the laminated structure is preferably performed in a shared manner from the viewpoint of productivity, and a known curing method may be used. For example, in the case of the film A, a film may be produced by piling and laminating a solution containing an acrylic resin and a solution containing a cellulose ester from a plurality of oil samples formed at intervals in the advancing direction of the metal support, For example, Japanese Patent Application Laid-Open No. 61-158414, Japanese Patent Application Laid-Open No. 1-122419, Japanese Patent Application Laid-Open No. 11-198285, and the like. In addition, from the two oil studies, a solution containing an acrylic resin and a solution containing a cellulose ester may be made into a film by being softened. For example, JP-A 60-27562, JP-A 61-94724 Japanese Patent Application Laid-Open No. 61-947245, Japanese Patent Application Laid-Open No. 61-104813, Japanese Patent Application Laid-Open No. 61-158413, Japanese Patent Application Laid-Open No. 6-134933, etc. .

Fig. 8 is a schematic view showing formation of a shared lead die and a flexible multi-layer structure web.

In the figure, the common tie die 50, the cementing member part 51, the layer B, the slits 53 and 55 for the layer C, the slit 54 for the layer A, the metal support 56, The dope 57 and 59, the layer A doping 58, the multi-layer structure web 60, the layer C 61, the layer A 62 and the layer B 63, respectively.

(3) Solvent Evaporation Process

A web (a dope is formed on a flexible support and the formed dope is referred to as a web) is heated on a flexible support to evaporate the solvent.

In order to evaporate the solvent, there are a method of blowing air from the web side, a method of heating by the liquid from the back side of the support, and a method of transferring heat from the front and back by radiant heat. . Also, a method of combining them is also preferably used. It is preferable to dry the web on the supporter after the softening on the support in an atmosphere of 40 to 100 캜. In order to maintain the temperature at 40 to 100 DEG C, it is preferable to heat the warm air at this temperature to the upper surface of the web or to heat it by means of infrared rays or the like.

From the standpoint of surface quality, moisture permeability and releasability, it is preferable to peel the web from the support within 30 to 120 seconds.

(4) Peeling process

And peeling the web from which the solvent has evaporated on the metal support at the peeling position. The peeled web is sent to the next process.

The temperature at the peeling position on the metal support is preferably in the range of 10 to 40 占 폚, more preferably in the range of 11 to 30 占 폚.

The amount of the residual solvent at the time of peeling the web on the metal support at the time of peeling is desirably peeled in the range of 50 to 120 mass% depending on the strength of the drying condition, the length of the metal support, etc., When the web is peeled off at many points of time, if the web is too soft, the flatness is deteriorated in peeling, and peeling tension or vertical stripes tend to occur due to the peeling tension. Therefore, in consideration of the balance between economic speed and quality, do.

The amount of residual solvent in the web is defined by the following formula (Z).

The formula (Z)

Residual solvent amount (%) = (mass before heat treatment of web-mass after heat treatment of web) / (mass after heat treatment of web) 占 100

The heat treatment at the time of measuring the residual solvent amount means that the heat treatment is performed at 115 캜 for one hour.

The peeling tension when peeling the film from the metal support is usually in the range of 196 to 245 N / m, and it is preferable to peel off with a tensile force of 190 N / m or less when wrinkles tend to occur at peeling.

In the present invention, the temperature at the peeling position on the metal support is preferably in the range of -50 to 40 占 폚, more preferably in the range of 10 to 40 占 폚, and most preferably in the range of 15 to 30 占 폚 .

(5) Drying and drawing process

The drying process may be divided into a preliminary drying process and a main drying process.

(Preliminary drying step)

The web obtained by peeling from the metal support is dried. The web may be dried while conveying the web by a plurality of rollers arranged vertically, or both ends of the web may be fixed with a clip such as a tenter dryer and dried while being conveyed.

The means for drying the web is not particularly limited and can generally be carried out by hot air, infrared rays, heating rollers, microwaves or the like, but from the viewpoint of simplicity, it is preferable to conduct it by hot air.

It is effective that the drying temperature in the drying step of the web is preferably a heat treatment at a glass transition point of the film of -5 DEG C or less and at 100 DEG C or more for 10 minutes or more and 60 minutes or less. The drying is carried out at a temperature in the range of 100 to 200 ° C, more preferably in the range of 110 to 160 ° C.

(Drawing step)

The cellulose acetate film according to the present invention is preferably stretched in the MD direction and / or the TD direction and is preferably stretched in the TD direction by at least a tenter stretching apparatus.

Such stretching may be uniaxial stretching or biaxial stretching, and in biaxial stretching, stretching in one direction and stretching in the other direction may be relaxed to shrink.

The acrylic film according to the present invention is preferably stretched in the MD direction and / or the TD direction such that the film thickness after stretching is in the range of 20 to 60 mu m, and the cellulose acetate film is in the MD film thickness after stretching in the range of 20 to 60 mu m, (Tg + 15) to (Tg + 50) deg. C, where Tg is the glass transition temperature of the film, preferably in the TD direction. If the stretching is carried out within the above-mentioned temperature range, the retardation can be easily adjusted and the stretching stress can be lowered, thereby lowering the haze. Further, it is possible to obtain a polarizing plate protective film which suppresses the occurrence of rupture and is excellent in planarity and colorability of the film itself. The stretching temperature is preferably in the range of (Tg + 20) to (Tg + 40) deg.

The term "glass transition temperature (Tg)" as used herein means a value obtained by measuring a glass transition temperature (Tmg) measured according to JIS K7121 (1987) to be.

The specific glass transition temperature (Tg) of the optical film is measured using a differential scanning calorimeter DSC220 manufactured by Seiko Instruments Inc. according to JIS K7121 (1987).

The acrylic film according to the present invention is preferably stretched in the range of 1.05 to 1.5 times the original width in the TD direction. By stretching within the above range, the planarity can be improved and the behavior of the dimensional change can be controlled within a desired range.

In addition, the cellulose acetate film according to the present invention preferably stretches the web at least 1.1 times in the TD direction. The range of the stretching is preferably in the range of 1.1 to 1.5 times the original width, and more preferably in the range of 1.05 to 1.3 times. Within the above range, the movement of molecules in the film is large, and not only a desired retardation value is obtained, but also the behavior of the dimensional change of the film can be controlled within a desired range.

When the amount of the residual solvent after the film formation is 40% by mass or more, the film is preferably stretched in the MD direction, and when the amount of the residual solvent is less than 40% by mass, the film is preferably stretched in the TD direction.

In order to stretch in the MD direction, the peel tension is desirably peeled to 130 N / m or more, particularly preferably 150 to 170 N / m. Since the web after peeling is in a state of high residual solvent, stretching in the MD direction can be performed by maintaining the same tensile force as the peeling tension. As the web dries and the amount of the residual solvent decreases, the elongation in the MD direction decreases.

The drawing magnification in the MD direction can be calculated from the rotating speed of the belt support and the tenter operating speed.

In order to stretch in the TD direction, for example, a method of drying the entire drying step or a part of the steps as disclosed in Japanese Patent Application Laid-Open No. 62-46625 while keeping the both ends of the web width wide (Called a tenter system), among which a tenter system using a clip and a pin tenter system using a fin are preferably used.

The retardation value Ro and the retardation value Rt in the thickness direction of the cellulose acetate film according to the present invention necessarily have retardation by stretching the retardation value Rt in the thickness direction of the cellulose acylate film according to the present invention in an automatic double reflex index system scan (Axo Scan Mueller Matrix Polarimeter: The refractive indices nx, ny and nz can be calculated by measuring the three-dimensional refractive index at a wavelength of 590 nm under the environment of 23 占 폚 and 55% RH by using the refractive index nx, ny, and nz.

The cellulose acetate film according to the present invention is characterized in that the retardation value Ro in the in-plane direction defined by the following formulas (i) and (ii) is in the range of 40 to 60 nm and the retardation value Rt in the thickness direction is 100 To 140 nm is preferable from the viewpoint of improving the visibility of the VA mode liquid crystal display device. The cellulose acetate film can be adjusted within the range of the retardation value by stretching while at least adjusting the stretching magnification in the TD direction.

Formula (i): Ro = (n x -n y) × d (nm)

Formula (ii): Rt = {( n x + n y) / 2-n z} × d (nm)

[In the formulas (i) and (ii), n _x represents the refractive index in the direction x at which the refractive index becomes maximum in the in-plane direction of the film. n _y represents the refractive index in the direction y perpendicular to the direction x in the in-plane direction of the film. and n _z represents the refractive index in the thickness direction z of the film. d represents the thickness (nm) of the film]

<Bending Process>

The cellulose acetate film according to the present invention is characterized in that in the step of stretching the web and subsequently drying in the dryer zone in order to adjust the rate of dimensional change immediately after changing the atmosphere of temperature and humidity in the environment, And the bending process is performed such that the bending process is performed by bending the web so that the B side opposite to the A side of the web is alternately inward by the conveying roller in the dryer zone, when the radius of the time went off by a (mm), and the value of 1 / a in the range of 0.035mm to 0.050mm ^{-1 -1,} also preferable that dry by performing the bending, while repeated at least 50 times less than 120 times Do.

The bending process preferable for the present invention will be described with reference to the drawings. However, the present invention is not limited to this.

9 is a schematic view of a bending treatment apparatus that can be preferably applied to the present invention.

The dope 101 from the dies 101 is softened on the metal support 102 and successively dried on the metal support by the drive roller 103 so that the web (the name of the dope after being softened on the metal support is referred to as the web ). The web is dried so that the residual solvent amount becomes a desired value, and is peeled off in the form of a film at the peeling point 104, followed by preliminary drying, stretching processing (not shown), conveyed to the bending zone 106, The surface A (the surface of the web opposite to the surface contacting with the metal support) and the surface B (the surface of the web contacting the metal support) are alternately conveyed to the inside of the conveying roller 105 by the conveying roller 105, The bending process is repeated. The bending process is performed in a bending zone 106 having an inlet 107 and an outlet 108, and the film is adjusted to bend at the desired ambient temperature.

The diameter of the conveying roller is preferably in the range of 90 to 108 mm, and the distance between the rollers is preferably about 1800 mm. When the radius of the bent when the film with a (mm) is When the value of the 1 / a determines the diameter of the roller so that within the range of 0.035mm to 0.050mm ^{-1 -1.}

In the bending zone 106, the temperature-adjusted hot air is introduced from the inlet 107 to keep the inside of the bending zone 106 at a constant atmospheric temperature and is exhausted from the exhaust port 108. In order to adjust the atmospheric temperature in the bending zone 106, it may be performed by infrared rays, a heating roller, or the like, but it is preferable to perform hot air in terms of simplicity. In addition, the atmosphere in the drying apparatus may be air, but it may be performed in an inert gas atmosphere such as nitrogen gas, carbon dioxide gas, and argon.

The temperature of the atmosphere during the bending treatment of the cellulose acetate film according to the present invention is preferably in the range of 130 to 150 占 폚 and preferably in the range of 135 to 150 占 폚 in order to obtain the effect of the present invention.

The number of times of bending of the cellulose acetate film according to the present invention is preferably 50 times or more and less than 120 times, more preferably 70 times or more and 100 times or less. The bending interval of the film is preferably within a range of 1 second to 1 minute, and more preferably within a range of 2 to 30 seconds.

The conveying speed of the cellulose acetate film according to the present invention is preferably in the range of 10 to 150 m / min, more preferably in the range of 15 to 100 m / min from the viewpoint of productivity and breakage.

<Cooling Process>

The acrylic film according to the present invention is manufactured by a process of drying a web in a dryer zone and a process of drying the web at a temperature of 50 to 100 deg. And a cooling step of cooling the web at a speed in a range of 100 DEG C / sec.

After the step of drying the stretched web in the dryer zone, a cooling step of cooling the web at a speed in the range of 50 to 100 ° C / sec is added to form a dense molecular chain state of the film so that the water content And the contraction ratio of the film containing moisture can be effectively controlled. The cooling rate is more preferably in the range of 70 to 90 DEG C / sec.

In order to cool the web, for example, it is preferable to connect the cooling zone 109 in Fig. 9 after the bending zone 106 as the drying process.

The means for cooling the web is not particularly limited and can be generally performed by using a cold air nozzle, a cooling roller or the like. In terms of simplicity, it is preferable that the web is transported in the cooling zone and the cold air is jetted from the cold air nozzle desirable. It is preferable to spray cool air on both sides of the web at this time because the web can be cooled with high precision.

<Knurling>

After a predetermined heat treatment or cooling treatment, it is preferable to provide a slitter before winding to cut off the end portion in order to obtain a good winding form. It is preferable to perform knurling at both end portions in the width direction.

The knurling can be formed by dipping the heated embossing roller. The embossing roller is formed with fine irregularities, and by pressing it, dents can be formed on the film to increase the volume of the end portion.

The height of the knurling at both ends in the width direction of the retardation film of the present invention is preferably in the range of 4 to 20 mu m and in the range of 5 to 20 mm in width.

Further, in the present invention, it is preferable that the knurling is performed after completion of drying in the film-forming step of the film and before winding.

(6) Coiling process

When the amount of the residual solvent in the web becomes 2% by mass or less, the film is taken up as a film. When the residual solvent amount is 0.4% by mass or less, a film having good dimensional stability can be obtained.

As the winding method, those generally used may be used, and there are a static torque method, a constant tension method, a taper tension method, an internal stress and a constant program tension control method, and they may be used separately.

[Physical properties of protective film]

(Hayes)

The protective film according to the present invention preferably has a haze of less than 1%, more preferably less than 0.5%. When the haze is less than 1%, the transparency of the film becomes higher and the optical film becomes easier to use.

(Equilibrium moisture content)

The protective film according to the present invention preferably has an equilibrium moisture content of 4% or less at 25 캜 and 60% relative humidity, and more preferably 3% or less. By setting the equilibrium moisture content to 4% or less, it is preferable because it is easy to cope with humidity change and optical properties and dimensions are hardly changed.

(Film length, width)

The protective film of the present invention is preferably long, and more specifically, preferably has a length of about 100 to 10000 m, and is wound in a roll form. The width of the protective film of the present invention is preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably 1.4 to 4 m.

«Polarizer»

The polarizing plate of the present invention is characterized in that the polarizer is sandwiched between the film A and the film B according to the present invention via the active ray curable adhesive layer.

When the polarizing plate of the present invention is used as a polarizing plate on the viewer side, it is preferable to provide an antiglare layer or a clear hard coating layer, an antireflection layer, an antistatic layer, a scattering layer, or the like on the viewer side of the film A.

[Polarizer]

The polarizer, which is a main component of the polarizing plate according to the present invention, is a device for carrying out only the light of a polarization plane in a certain direction, and a typical polarizer currently known is a polyvinyl alcohol polarizing film. The polyvinyl alcohol polarizing film includes a polyvinyl alcohol film stained with iodine and a dichroic dye stained.

As the polarizer, a polarizer in which a polyvinyl alcohol aqueous solution is formed, uniaxially stretched, dyed, uniaxially stretched, and preferably subjected to a durability treatment with a boron compound can be used. The film thickness of the polarizer is preferably in the range of 2 to 30 mu m, particularly preferably in the range of 2 to 15 mu m.

Further, an ethylene-modified polyvinyl alcohol having an ethylene unit content of 1 to 4 mol%, a degree of polymerization of 2000 to 4000 and a saponification degree of 99.0 to 99.99 mol% described in JP-A-2003-248123 and JP-A-2003-342322 Alcohol is also preferably used. Among them, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 占 폚 is preferably used. A polarizer using this ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability, and has less color unevenness and is particularly preferably used in a large-sized liquid crystal display device.

[Polarizer of laminated film type]

Further, since the polarizing plate of the present invention is a thin film, it is particularly preferable that the thickness of the polarizer is within a range of 2 to 15 탆 from the viewpoint of achieving both strength and thinning of the polarizing plate.

As such a polarizer of a thin film, it is possible to manufacture a laminated film type polarizer by the method described in Japanese Patent Application Laid-Open Nos. 11-116111, 1186161, 128631/1994, desirable.

As an example, it is particularly preferable to use a laminated film-type polarizer (polarizing laminated film) of a thin film produced by the following steps because it can improve the display unevenness and adhesion, which are effects of the present invention.

(Method for producing a polarizing laminated film)

The method for producing a polarizing laminated film according to the present invention includes the following steps.

(a) a lamination step of forming a polyvinyl alcohol-based resin layer on one side of a base film in which a rubber component is dispersed in a thermoplastic resin to obtain a laminated film,

(b) a stretching step of obtaining a stretched film by uniaxially stretching the laminated film,

(c) a dyeing step of dying a polyvinyl alcohol-based resin layer of a stretched film with a dichroic dye to obtain a dyeing film,

(d) a crosslinking step of immersing the polyvinyl alcohol-based resin layer of the dye film in a solution containing a crosslinking agent to form a polarizer layer, and obtaining a crosslinked film, and

(e) a drying process for drying the crosslinked film

Hereinafter, each step will be described.

(a) Laminating process

In this step, a film formed by dispersing (blending and dispersing) a rubber component in a thermoplastic resin is used as a base film, and a polyvinyl alcohol-based resin layer is formed on one side thereof to obtain a laminated film.

(Substrate film)

The thermoplastic resin serving as the base of the base film is preferably a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, stretchability and the like. Specific examples of such a thermoplastic resin include, for example, a chain polyolefin-based resin; A cyclic polyolefin-based resin; (Meth) acrylic resins; Polyester-based resin; Cellulose ester resins; Polycarbonate resin; Polyvinyl alcohol-based resin; Vinyl acetate resin; Polyarylate resins; Polystyrene type resin; Polyether sulfone type resin; Polysulfone resins; Polyamide based resin; Polyimide resin; And mixtures or copolymers thereof.

The rubber component dispersed in the thermoplastic resin is a resin component having rubber elasticity and is usually uniformly dispersed in the thermoplastic resin as rubber particles. By mixing and dispersing the rubber components, the tensile rupture strength of the base film and thus the stretched film can be improved. The rubber component is not particularly limited as long as it is a resin having rubber elasticity, but from the viewpoint of compatibility with the thermoplastic resin, it is preferable that the rubber component is composed of the same or similar resin as the thermoplastic resin to be used.

For example, when the thermoplastic resin is a chain polyolefin-based resin, the rubber component may be a copolymer of two or more kinds of monomers selected from ethylene and? -Olefin. In this case, the content (polymerization ratio) of each monomer constituting the copolymer is preferably less than 90% by mass, more preferably less than 80% by mass.

When the thermoplastic resin is a (meth) acrylic resin, it is preferable to contain an acrylic polymer having rubber elasticity as a rubber component from the viewpoint of compatibility. The acrylic polymer may be a polymer mainly composed of alkyl acrylate or may be a homopolymer of alkyl acrylate or a copolymer of 50 mass% or more of alkyl acrylate and 50 mass% or less of other monomer.

The blending amount of the rubber component is preferably 5 to 50 mass%, more preferably 10 to 45 mass%, of the thermoplastic resin. If the blending amount of the rubber component is too small, a sufficient improvement effect of the tensile rupture strength tends to be hardly obtained. If the blending amount of the rubber component is too large, the handling property of the base film tends to be lowered.

The method of dispersing the rubber component in the thermoplastic resin is not particularly limited, and examples thereof include a method of kneading and dispersing a separately prepared thermoplastic resin and a rubber component (rubber particle) with a plastometer or the like, And a reactor blend method in which a rubber component is also produced in a reaction vessel to obtain a thermoplastic resin in which a rubber component is dispersed. The reactor blend method is advantageous in improving the degree of dispersion of the rubber component.

(Polyvinyl alcohol-based resin layer)

Examples of the polyvinyl alcohol-based resin forming the polyvinyl alcohol-based resin layer include a polyvinyl alcohol resin and derivatives thereof. Examples of the derivative of the polyvinyl alcohol resin include polyvinyl formal, polyvinyl acetal, and the like. The polyvinyl alcohol resin may be mixed with an unsaturated carboxylic acid such as olefin such as ethylene or propylene, acrylic acid, methacrylic acid or crotonic acid, Or an alkyl ester, acrylamide, or the like. Of these, polyvinyl alcohol resins are preferably used.

The polyvinyl alcohol-based resin is preferably a completely saponified product. The degree of saponification is preferably in the range of 80.0 to 100.0 mol%, more preferably in the range of 90.0 to 99.5 mol%, still more preferably in the range of 94.0 to 99.0 mol%.

Additives such as a plasticizer and a surfactant may be added to the above-mentioned polyvinyl alcohol-based resin, if necessary. As the plasticizer, a polyol and condensates thereof can be used, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the additive to be blended is not particularly limited, but is preferably 20% by mass or less of the polyvinyl alcohol-based resin.

Examples of the method of applying the polyvinyl alcohol resin solution to the substrate film include a roll coating method such as a wire bar coating method, a reverse coating method and a gravure coating method, a spin coating method, a screen coating method, a fountain coating method, a dipping method, Can be appropriately selected from known methods of &lt; RTI ID = 0.0 &gt; The drying temperature is, for example, in the range of 50 to 200 占 폚, preferably in the range of 60 to 150 占 폚. The drying time is, for example, in the range of 2 to 20 minutes.

The thickness of the polyvinyl alcohol-based resin layer in the laminated film is preferably from 3 탆 to 50 탆, and more preferably from 5 탆 to 45 탆. If the thickness is 3 m or less, the thickness becomes too thin after stretching to remarkably deteriorate the dyability. If it exceeds 50 m, the resulting polarizing laminated film becomes thick.

The thickness of the polyvinyl alcohol-based resin layer used as the polarizer used in the present invention is preferably in the range of 2 to 15 탆 in film thickness after the stretching treatment described below, from the viewpoint of thinning, strength as a polarizer, and flexibility.

(b)

This step is a step of uniaxially stretching a laminated film comprising a base film and a polyvinyl alcohol-based resin layer to obtain a stretched film. The stretching magnification of the laminated film can be appropriately selected in accordance with the desired polarization characteristics, but is preferably 5 times or more and 17 times or less, more preferably 5 times or more and 8 times or less the original length of the laminated film.

The stretching is preferably longitudinal stretching in which the stretching is performed in the longitudinal direction (film transport direction) of the laminated film. Examples of the longitudinal stretching method include an inter roller stretching method, a compression stretching method, and a stretching method using a tenter. The uniaxial stretching is not limited to the longitudinal stretching process, but may be inclined stretching.

(c) Dyeing process

In this step, the polyvinyl alcohol resin layer of the drawn film is dyed with a dichroic dye to obtain a dye film. Examples of the dichroic dye include iodine and organic dyes. Examples of the organic dyes include red BR, red LR, red R, pink LB, rubin BL, bordeaux GS, sky blue LG, lemon yellow, blue BR, blue 2R, navy RY, green LG, violet LB, violet B , Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, , Direct Fast Orange S, and First Black. These dichroic substances may be used alone, or two or more of them may be used in combination.

When iodine is used as the dichroism dye, it is preferable to add iodide to the dyeing solution containing iodine in order to further improve the dyeing efficiency. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide.

(d) Crosslinking Process

This step is a step of obtaining a crosslinked film having a polyvinyl alcohol resin layer as a polarizer layer by performing a crosslinking treatment on a polyvinyl alcohol resin layer of a dye film obtained by dying with a dichroic dye. The crosslinking step can be carried out, for example, by immersing the dyeing film in a solution (crosslinking solution) containing a crosslinking agent. As the crosslinking agent, conventionally known substances can be used. Examples thereof include boron compounds such as boric acid and borax, and glyoxal and glutaraldehyde. These may be used alone or in combination of two or more.

(e) Drying process

The resulting crosslinked film is usually washed and then dried. Thus, a polarizing laminated film is obtained. The cleaning can be performed by immersing the crosslinked film in pure water such as ion-exchanged water or distilled water. The water washing temperature is usually within the range of 3 to 50 占 폚, preferably within the range of 4 to 20 占 폚. The immersion time is usually in the range of 2 to 300 seconds, preferably in the range of 5 to 240 seconds. The cleaning may be a combination of a cleaning treatment with a iodide solution and a water cleaning treatment, or a solution in which a liquid alcohol such as methanol, ethanol, isopropyl alcohol, butanol, or propanol is blended.

As the drying method, any appropriate method (for example, natural drying, air blow drying, heat drying) may be employed. For example, in the case of heat drying, the drying temperature is usually in the range of 20 to 95 占 폚, and the drying time is usually about 1 to 15 minutes.

The polarizing laminated film has a polarizer layer including a polyvinyl alcohol-based resin layer in which a dichroism dye is adsorbed and oriented, and can itself be used as a polarizing plate. As a preferred embodiment of the present invention, after the polarizing laminated film is formed by the above process, the polyvinyl alcohol layer of the polarizing laminated film is peeled off from the base film to form the polyvinyl alcohol layer, . According to the method of the present invention, since the thickness of the polarizer layer can be 15 m or less, a thin polarizer can be obtained. Further, the polarizer used in the present invention is excellent in polarization performance and durability.

[Active ray curable adhesive]

The polarizing plate according to the present invention is characterized in that the acrylic film, the protective film, and the polarizer and the cellulose acetate film described above and the polarizer are bonded together by an active ray curable adhesive.

Further, as the active ray curable adhesive, it is preferable to use the following ultraviolet curable adhesive.

In the present invention, by applying an ultraviolet curable adhesive to the bonding of the protective film and the polarizer, polarizing plate characteristics having high strength and excellent planarity can be obtained even in a thin film.

[Composition of ultraviolet curable adhesive]

As the ultraviolet curable adhesive composition for a polarizing plate, there are known a photo radical polymerization type composition using photo radical polymerization, a photo cation polymerization type composition using photo cation polymerization, and a hybrid type composition using photo radical polymerization and photo cation polymerization in combination.

Examples of the photo-radical polymerization type composition include compositions containing a radical polymerizing compound containing a polar group such as a hydroxyl group or a carboxyl group and a radically polymerizable compound containing no polar group in a specific ratio described in JP-A-2008-009329 Is known. In particular, the radical polymerizing compound is preferably a compound having a radically polymerizable ethylenic unsaturated bond. Preferable examples of the compound having a radically polymerizable ethylenically unsaturated bond include a compound having a (meth) acryloyl group. Examples of the compound having a (meth) acryloyl group include N-substituted (meth) acrylamide-based compounds, (meth) acrylate-based compounds and the like. (Meth) acrylamide means acrylamide or methacrylamide.

As the photo cationic polymerization type composition, there may be mentioned (a) a cationic polymerizable compound, (?) A photo cationic polymerization initiator, (?) A photoacid generator having a wavelength longer than 380 nm (隆) naphthalene-based photo-sensitization assistant, and an ultraviolet curable adhesive composition containing the respective components of a photo-sensitizer and 隆 -naphthalene-based photosensitizer. However, other ultraviolet curable adhesives may be used.

(Pre-processing step)

The pretreatment step is a step of performing adhesion facilitating treatment on the adhesion surface of the protective film to the polarizer. When the film A and the film B, which are protective films, are adhered to both sides of the polarizer, adhesion facilitating treatment is performed on the adhesion surface of each protective film to the polarizer. Examples of the adhesion facilitating treatment include corona treatment and plasma treatment.

(Application step of ultraviolet curing type adhesive)

In the application step of the ultraviolet curable adhesive, the ultraviolet curable adhesive is applied to at least one of the bonding surfaces of the polarizer and the protective film. When the ultraviolet curable adhesive is directly applied to the surface of the polarizer or the protective film, the application method is not particularly limited. For example, various wet coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Further, a method may be employed in which an ultraviolet curable adhesive is poured between the polarizer and the protective film, followed by pressing with a roller or the like to uniformly spread the adhesive.

(Bonding step)

After the ultraviolet curable adhesive is applied by the above method, it is treated in the bonding step. In this bonding step, for example, when an ultraviolet curable adhesive is applied to the surface of the polarizer in the previous coating step, the protective film is superimposed thereon. Further, in the case of a method in which an ultraviolet curable adhesive is first applied to the surface of the protective film, a polarizer is superposed thereon. Further, when an ultraviolet curable adhesive is poured between the polarizer and the protective film, the polarizer and the protective film overlap with each other in this state. Normally, in this state, it is pressed between the both sides of the protective film side with a pressing roller or the like. As the material of the pressure roller, metal or rubber can be used. The pressure rollers disposed on both sides may be the same material or different materials.

(Curing Process)

In the curing step, ultraviolet rays are irradiated to an uncured ultraviolet curable adhesive to form a cationic polymerizable compound (for example, an epoxy compound or an oxetane compound) or a radical polymerizable compound (for example, an acrylate compound or an acrylamide compound Compound, etc.) is cured, and a superposed polarizer and a protective film or a polarizer and a retardation film are bonded to each other via an ultraviolet curable adhesive. When a protective film is bonded to one surface of the polarizer, the active energy ray may be irradiated from either the polarizer side or the protective film side. When the protective film and the retardation film are bonded to both surfaces of the polarizer, the protective film and the retardation film are superimposed on both surfaces of the polarizer with an ultraviolet curable adhesive interposed therebetween. It is advantageous to cure.

The irradiation condition of the ultraviolet ray may be any suitable condition as long as it is a condition capable of curing the ultraviolet curable adhesive applied in the present invention. Dose of ultraviolet radiation at a cumulative light intensity and in a range of 50 to 1500mJ / cm ² preferably, and more preferably in a range of 100 to 500mJ / cm ^2.

When the production process of the polarizing plate is performed in a continuous line, the line speed varies depending on the curing time of the adhesive, but is preferably in the range of 1 to 500 m / min, more preferably in the range of 5 to 300 m / min, Is in the range of 10 to 100 m / min. When the line speed is 1 m / min or more, the productivity can be ensured, or the damage to the protective film A can be suppressed, and a polarizer excellent in durability can be manufactured. When the line speed is 500 m / min or less, the curing of the ultraviolet curing type adhesive becomes sufficient, so that the ultraviolet curing type adhesive layer having the desired hardness and excellent adhesiveness can be formed.

&Quot; Liquid crystal display device &

By using the polarizing plate bonded with the protective film according to the present invention in the liquid crystal display device, the liquid crystal display device of the present invention having excellent visibility can be manufactured.

The polarizing plate of the present invention can be used in liquid crystal display devices of various driving methods such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS, and OCB. And is preferably a VA (MVA, PVA) type liquid crystal display device.

In a liquid crystal display device, two polarizing plates, that is, a polarizing plate on the viewer's side and a backlight side, are usually used, and it is also preferable to use the polarizing plate of the present invention as both polarizing plates. Particularly, it is preferable that the polarizing plate of the present invention is used as a polarizing plate on the side of the viewer who is in direct contact with the external environment. At that time, the acrylic film according to the present invention is disposed on the viewer side, and the cellulose acetate film according to the present invention, Is preferably disposed on the liquid crystal cell side.

In this case, both sides of the polarizer can be coated with a commercially available cellulose ester film (for example, Konica Minolta Tact KC8UX, KC5UX, KC4UX, KC8UCR3, KC4UH, KC4UA, KC4UA, KC4UH, KC4UH, KC4UH, KC4UR, KC4FR, KC4KR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY- Fujitac T60UZ, Fujitac T80UZ, Fujitac TD80UL, Fujitac TD60UL, Fujitac TD40UL, Fujitac R02, Fujitac R06, manufactured by Fuji Photo Film Co., Ltd.) are preferably used.

As the polarizing plate on the backlight side, a cellulose acetate film according to the present invention is used on the liquid crystal cell side of the polarizer, and a polarizing plate on which the commercially available cellulose ester film, polycarbonate film or cycloolefin polymer film is bonded to the opposite side Can be preferably used.

By using the polarizing plate of the present invention, it is possible to obtain a liquid crystal display device having excellent visibility such as display unevenness, frontal contrast, and the like, even in the case of a liquid crystal display of a large screen having a screen of 30 or more in particular.

Further, the polarizing plate of the present invention can be suitably used in an organic electroluminescence display device in addition to a liquid crystal display device.

Example

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. In the examples, &quot; part &quot; or &quot;% &quot; is used, and &quot; mass part &quot; or &quot; mass% &quot;

Example 1

&Lt; Production of Film A and Film B >

[Production of film A-101]

Film A-101, which is a film containing an acrylic resin, was produced by the following method.

(Preparation of fine particle dispersion diluent)

90 parts by mass of ethanol was mixed with a dissolver for 30 minutes with stirring, 10 parts by mass of an aerosol of 972 V (primary average particle diameter: 16 nm, outer specific gravity: 90 g / L, manufactured by Nippon Aerosil Co., Manton-Gaulin) to prepare a fine particle dispersion.

To the resulting fine particle dispersion, 88 parts by mass of dichloromethane was added with stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes to dilute. The resulting solution was filtered through a polypropylene wind cartridge filter TCW-PPS-1N manufactured by Advanec Tire Co., Ltd. to obtain a fine particle dispersion diluted solution.

(Preparation of in-line addition liquid)

15 parts by mass of Tinuvin 928 (manufactured by BASF Japan) and 100 parts by mass of dichloromethane as an ultraviolet absorber were placed in a sealed container, which was completely dissolved by heating and filtration. To the obtained solution, 36 parts by mass of the above-mentioned fine particle dispersion diluted solution was added with stirring and further stirred for 30 minutes, and then 6 parts by mass of acrylic resin: DIANAL BR85 (manufactured by Mitsubishi Rayon Co., Ltd., Mw: 280000) Lt; / RTI &gt; The solution thus obtained was filtered with Pine Met NF manufactured by Nippon Seisen Co., Ltd. to obtain an inline addition liquid. As the filter medium, a filter having a nominal filtration accuracy of 20 mu m was used.

(Preparation of Dope 1)

The following components were put in a hermetically sealed container and completely dissolved with heating and stirring. The obtained solution was filtered through an Azumirosi No.24 manufactured by Azumi Co., Ltd. to obtain a main doping 1.

&Lt; Composition of main doping 1 >

Acrylic resin 1: Dianal BR85 (manufactured by Mitsubishi Rayon Co., Ltd., acrylic resin Mw: 280000) 85 parts by mass

Ester: BzSc (benzyl saccharose: mixture of compounds g-1 to g-4 described in formula (4)), average ester substitution degree = 6.0 10 parts by mass

Polycondensation ester: The polycondensation ester P1 represented by the formula (1) 5 parts by mass

Methylene chloride 360 parts by mass

ethanol 15 parts by mass

100 parts by mass of the main dope 1 and 2.5 parts by mass of the inline addition liquid were thoroughly mixed with an inline mixer (Toray stationary in-tube mixer Hi-Mixer, SWJ) to obtain Dope 1.

(Film forming step)

The obtained dope 1 was uniformly smoothed on a stainless steel band support using a belt softener under the conditions of a solution temperature of 35 占 폚 and a width of 1.7 m in the condition of the final film thickness of 40 占 퐉. On the stainless steel band support, the organic solvent in the obtained dope film was evaporated to a residual solvent amount of 100% by mass to form a web, and then the web was peeled from the stainless band support. The obtained web was preliminarily dried at 110 캜 for 10 minutes, and then the web was stretched 1.5 times with respect to the original width in the TD direction at 160 캜 in a tenter. The amount of residual solvent in the web at the start of the stretching was 2.0% by mass. After being stretched by a tenter, the film was relaxed at 130 占 폚 for 5 minutes and then conveyed at 130 占 폚 for 15 minutes by a dryer (bending zone 106) shown in Fig. 9, min to 23 &lt; 0 &gt; C. The resulting film was slit at a width of 2.0 m and knurled at both ends of the film to a width of 10 mm and a height of 5 탆 and wound around a core of 15.24 cm in inner diameter at an initial tension of 220 N / m and a final tension of 110 N / m, A film A-101 containing a long acrylic resin of 40 mu m was obtained.

[Preparation of films A-102 to A-138]

The film A-102 containing the long acrylic resin shown in Tables 1 and 2 was prepared in the same manner as in the production of the film A-101 except that the cooling step, the cooling rate in the cooling zone and the film thickness were changed. To A-138.

[Production of film B-101]

(Preparation of fine particle dispersion diluent)

10 parts by mass of Aerosil R812 (manufactured by Nippon Aerosil Co., Ltd., primary average particle diameter: 7 nm, outer specific gravity: 50 g / L) and 90 parts by mass of ethanol were mixed with a dissolver for 30 minutes while stirring. To prepare a fine particle dispersion.

To the resulting fine particle dispersion, 88 parts by mass of dichloromethane was added with stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes to dilute. The resulting solution was filtered through a polypropylene wind cartridge filter TCW-PPS-1N manufactured by Advanec Tire Co., Ltd. to obtain a fine particle dispersion diluted solution.

(Preparation of in-line addition liquid)

To the 100 parts by mass of dichloromethane was added 36 parts by mass of the above prepared fine particle dispersion diluted solution with stirring and further stirred for 30 minutes. 6 parts by mass of diacetyl cellulose (acetyl group substitution degree 2.3, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) was added with stirring, and the mixture was further stirred for 60 minutes. The solution thus obtained was filtered with Pine Met NF manufactured by Nippon Seisen Co., Ltd. to obtain an inline addition liquid. As the filter medium, a filter having a nominal filtration accuracy of 20 mu m was used.

(Preparation of Dope 2)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The obtained solution was filtered through an Azumirosi No.24 manufactured by Azumi Co., Ltd. to obtain a main doping 2. [

<Composition of main doping 2>

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7)   81 parts by mass

Polyhydric alcohol ester (compound represented by formula (2)): Exemplary compound 2-10   2 parts by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5   7 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P8   5 parts by mass

Retardation adjusting agent 1: The following compound   3 parts by mass

Additive A: The following compound   2 parts by mass

Dichloromethane   430 parts by mass

Methanol   11 parts by mass

100 parts by mass of the main dope 1 and 2.5 parts by mass of the inline addition liquid were thoroughly mixed with an inline mixer (Toray stationary type in-pipe mixer Hi-Mixer, SWJ) to obtain Dope 2.

(Film forming step)

The obtained dope 2 was uniformly smoothed on a stainless steel band support using a belt softener under the conditions of a solution temperature of 35 占 폚 and a width of 1.95 m and a final film thickness of 40 占 퐉. On the stainless steel band support, the organic solvent in the obtained dope film was evaporated to a residual solvent amount of 100% by mass to form a web, and then the web was peeled from the stainless band support. The obtained web was preliminarily dried at 110 캜 for 10 minutes, and then the web was stretched in a tenter at 1.2 캜 with respect to the original width in the TD direction at 160 캜. The amount of residual solvent in the web at the start of the stretching was 2.0% by mass. After being stretched by a tenter, the sheet was relaxed at 130 캜 for 5 minutes. Thereafter, the sheet was held at a temperature of 140 캜 by a dryer (bending zone 106) shown in Fig. 9, The diameter and the arrangement of the conveying rollers are set such that the value of 1 / a is 0.040 mm &lt; ^-1 &gt; when a (mm) represents a radius when the B side opposite to the A side of the web is alternately bent inward And the bending was repeated 80 times to convey the web at a conveyance speed of 20 m / min.

The resultant film was slit at a width of 2.0 m and knurled at both ends of the film to a thickness of 10 mm and a height of 5 탆 and wound around a core of 15.24 cm in inner diameter at an initial tension of 220 N / m and a final tension of 110 N / m, A film B-101 containing a long diacetyl cellulose having a thickness of 40 mu m was obtained.

[Production of films B-102 to B-138]

In the production of the film B-101, except that the acetyl group substitution degree of diacetyl cellulose (referred to as DAC substitution degree in the table), the value of 1 / a in the bending zone, the number of bending times and the film thickness were changed Similarly, the long films B-102 to B-132 described in Table 1 and Table 2 were obtained.

B-133 to B138 were produced in the same manner as in the production of B-132 by using the following main dope 3 to 8, respectively.

<Composition of main doping 3>

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 85 parts by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 10 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P7 2.5 parts by mass

Retardation adjusting agent 1: The following compound 2.5 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

<Composition of main dope 4>

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 86 parts by mass

Polyhydric alcohol ester (compound represented by formula (2)): Exemplary compound 2-1

1 part by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 10 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P2 2 parts by mass

Retardation adjusting agent 1: The following compound 2.2 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

<Composition of main doping 5>

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 85 parts by mass

Polyhydric alcohol ester (compound represented by formula (2)): Exemplary compound 2-1

1 part by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 10 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P2 2 parts by mass

Retardation adjusting agent 1: The following compound 2.5 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

<Composition of main doping 6>

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 85 parts by mass

Polyhydric alcohol ester (compound represented by formula (2)): Exemplary compound 2-9

1 part by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 10 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P2 2 parts by mass

Retardation adjusting agent 2: The following compound 2.5 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

<Composition of main doping 7>

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 87 parts by mass

Polyhydric alcohol ester (compound represented by formula (2)): Exemplary compound 2-9

1 part by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 10 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P1 2 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

<Composition of main doping 8>

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 86 parts by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 10 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P2 2 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

<Production of polarizing plate>

[Production of Polarizer 1]

A polarizing laminated film was prepared by the following process to form a polarizer of a thin film, and the base film was peeled from the polarizing laminated film to obtain a polarizer of a thin film.

(1) Production of base film

A thermoplastic resin and a rubber component were sequentially prepared by the reactor blend method in the same reaction vessel. Specifically, propylene monomer was fed in a gas phase as a first step by using a Ziegler-Natta catalyst, and a propylene homopolymer as a thermoplastic resin was produced. The feed of the propylene monomer was stopped to stop the reaction and the ethylene monomer and the propylene monomer were fed in the gas phase as they were in the reaction vessel as the second step to prepare an ethylene-propylene copolymer as the rubber component. -Propylene copolymer dispersed in particulate form was obtained. The content of the ethylene unit in the copolymer was determined from the mass balance at the time of polymerization and found to be 35 mass%. The content of the ethylene unit in the total resin (total of the thermoplastic resin and the rubber component) was determined according to the method described on page 616 of the Polymer Handbook (published by Kinokuniya Shoten in 1995) The content of the ethylene-propylene copolymer was 29 mass% (i.e., the content of the ethylene-propylene copolymer was 40.8 mass% of the thermoplastic resin).

The resulting mixed resin was melted and kneaded at 250 占 폚 and then melt-extruded at a temperature of 280 占 폚 on a T-die to obtain a base film having a thickness of 100 占 퐉.

(2) Formation of primer layer

Polyvinyl alcohol powder ("Z-200" manufactured by Nippon Gosei Chemical Industry Co., Ltd., average polymerization degree: 1100, average saponification degree: 99.5 mol%) was dissolved in hot water at 95 ° C to prepare a polyvinyl alcohol aqueous solution having a concentration of 3% . To the obtained aqueous solution, 5 parts by mass of a crosslinking agent ("Sumirez Resin 650" manufactured by Sumitomo Chemical Co., Ltd.) was added to 6 parts by mass of the polyvinyl alcohol powder. The obtained mixed aqueous solution was coated on the corona-treated surface of the substrate film subjected to the corona treatment using a micro gravure coater and dried at 80 DEG C for 10 minutes to form a 0.2 mu m thick primer layer.

(3) Formation of a polyvinyl alcohol-based resin layer

A polyvinyl alcohol aqueous solution having a concentration of 8% by mass was prepared by dissolving polyvinyl alcohol powder ("PVA124" manufactured by Kuraray Co., Ltd., average degree of polymerization: 2400, average saponification degree: 98.0 to 99.0 mol%) in hot water at 95 ° C. The obtained aqueous solution was coated on the primer layer using a lip coater and dried under the conditions of 80 캜 for 2 minutes, 70 캜 for 2 minutes and subsequently at 60 캜 for 4 minutes to form a primer layer Thereby producing a laminated film in which a polyvinyl alcohol-based resin layer was laminated. The thickness of the polyvinyl alcohol-based resin layer was 9.8 mu m.

(4) Production of stretched film

The laminated film was uniaxially stretched at a stretching temperature of 160 DEG C at a free end portion of 5.8 times to obtain a stretched film. The thickness of the obtained stretched film was 28.5 占 퐉, and the thickness of the polyvinyl alcohol-based resin layer was 5.0 占 퐉.

(5) Production of polarizing laminated film

The stretched film was immersed in a warm bath at 60 DEG C for 60 seconds and then dipped in a dyeing solution at 30 DEG C for about 150 seconds as an aqueous solution containing iodine and potassium iodide to stain the polyvinyl alcohol resin layer, Of the pure iodine solution. Subsequently, the substrate was immersed in a crosslinking solution at 76 DEG C for 600 seconds as an aqueous solution containing boric acid and potassium iodide. Thereafter, the film was washed with pure water at 10 캜 for 4 seconds, and finally dried at 50 캜 for 300 seconds to obtain a polarizing laminated film. The polyvinyl alcohol-based resin layer of the polarizing laminated film was peeled from the base film, and a polyvinyl alcohol-based resin layer was used as the polarizer.

[Preparation of ultraviolet curable adhesive liquid 1]

The following components were mixed and defoamed to prepare an ultraviolet curing type adhesive liquid 1. Further, triarylsulfonium hexafluorophosphate was compounded as a 50% propylene carbonate solution, and the solid content of triarylsulfonium hexafluorophosphate was shown below.

45 parts by mass of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate

40 parts by mass of Polyd GT-301 (alicyclic epoxy resin manufactured by Daicel Chemical Industries, Ltd.)

1,4-butanediol diglycidyl ether    15 parts by mass

Triarylsulfonium hexafluorophosphate   2.3 parts by mass

9,10-dibutoxyanthracene   0.1 parts by mass

1,4-diethoxynaphthalene   2.0 parts by mass

[Production of polarizing plate 101]

The polarizing plate 101 was produced by the following method.

First, the above-prepared film B-101 was used as a retardation film, and its surface was subjected to a corona discharge treatment. The conditions of the corona discharge treatment were a corona output power of 2.0 kW and a line speed of 18 m / min. Subsequently, on the corona discharge treated surface of the film B-101, the ultraviolet curable adhesive liquid 1 prepared above was applied and coated with a bar coater so as to have a film thickness after curing of about 3 탆 to form an ultraviolet curable adhesive layer. To the obtained ultraviolet curable adhesive layer, the polarizer (thickness 5 mu m) side of the prepared polarizing laminated film was bonded, and then the base film was peeled off.

Subsequently, corona discharge treatment was carried out using the thus prepared film A-101. The conditions of the corona discharge treatment were a corona output power of 2.0 kW and a velocity of 18 m / min.

Subsequently, on the corona discharge treated surface of the film A-101, the ultraviolet curable adhesive liquid 1 prepared above was applied and coated with a bar coater so that the film thickness after curing was about 3 占 퐉 to form an ultraviolet curable adhesive layer.

A polarizer bonded to one side of the film B-101 was bonded to this ultraviolet curable adhesive layer to obtain a laminate in which the film A-101 / ultraviolet curable adhesive layer / polarizer / ultraviolet curable adhesive layer / film B-101 were laminated. At that time, the film was bonded such that the slow axis of the film A-101 and the absorption axis of the polarizer were orthogonal to each other.

Ultraviolet rays were radiated from both sides of the laminated body so that the accumulated light quantity became 750 mJ / cm ² by using an ultraviolet irradiator equipped with a belt conveyor (the lamp was a D valve manufactured by Fusion UV Systems Co., Ltd.) The curable adhesive layer was cured to prepare a polarizing plate 101 having a total film thickness of 91 탆.

[Production of polarizer 102 to polarizer 138]

Using the films A-102 to A-138 and the films B-102 to B-138 in the same manner as the polarizing plate 101, the film A / ultraviolet curable adhesive layer / polarizer / Layer / film B, a polarizing plate 102 to a polarizing plate 138 were produced.

«Evaluation 1»

L ₁ MD, L ₁ TD, and L ₅ MD, respectively, for the film A-101 to the film A-138 and the film B-101 to the film B- L ₅ TD, L ₃₀ MD and L ₃₀ TD were measured. From the measurement _{results, (L 1 MD-L 5} MD), (L 1 TD-L 5 TD), each value of _{(L 5 MD-L 30 MD} ) and _{(L 5 TD-L 30 TD} ) (%) Respectively.

«Evaluation 2»

(Fabrication of liquid crystal display device)

A polarizing plate joined to the viewer side of the liquid crystal cell was peeled off using a commercially available VA type liquid crystal display device (SONY type 40 type display KLV-40J3000 manufactured by SONY), and the prepared polarizing plates 101 to 138 were placed on the liquid crystal cell side So that the film B was placed thereon to produce the liquid crystal display devices 101 to 138. The liquid crystal display device was manufactured by joining the absorption axis of the polarizing plate thus prepared so as to be in the same direction as the absorption axis of the polarizing plate previously bonded, and the display unevenness was evaluated by the following method.

(Evaluation of display unevenness)

The obtained liquid crystal display was allowed to stand in a constant temperature and humidity bath at 50 占 폚 and 90% RH for 1 hour and then left under a temperature and humidity environment of 23 占 폚 and 55% RH and the liquid crystal display was displayed in black at room temperature. The difference between the luminance near the four vertices and the luminance near the center of the display screen (display unevenness) was visually observed. The display unevenness was evaluated based on the following criteria. In the following evaluation,? And? Are preferable.

A: No display irregularity at all

○: slight noticeable irregularity is observed with very fine attention

△: display irregularity appears at one of four vertices

×: Display irregularity is observed at three or more of four vertices

(Evaluation of Polarizer Adhesion)

The resulting liquid crystal display was allowed to stand in a constant temperature and humidity bath at 80 캜 and 90% RH for 1 hour and then allowed to stand in a temperature and humidity environment of 23 캜 and 55% RH for 1 hour. One cycle was repeated 50 times, The phenomenon of crying and film peeling were observed, and the adhesion between the film A and the film B and the polarizer was evaluated.

◎: no phenomenon of panel surface crying or film peeling at all

○: When very careful attention is paid, the surface of the panel is slightly crying

?: Apparently crying appears on the surface of the panel, but no peeling occurs

X: Crying phenomenon and film peeling were observed on the surface of the panel

The structures of the film A and the film B, the composition of the polarizing plate, and the above evaluation results are collectively shown in Tables 1 and 2.

From Table 1 and Table 2, it can be seen that, in addition to the selection of the type of acrylic resin and the weight average molecular weight, the use of plasticizers such as sugar esters and polycondensation esters, and the adjustment of the film thickness, It can be understood that it is possible to adjust within the range of the dimensional change rate of the present invention by performing the cooling step of cooling the web at a speed in the range of 50 to 100 ° C / sec after the drying step (dryer zone) is exited.

Further, the film B can be obtained by selecting the acetyl group substitution degree and the weight average molecular weight of the cellulose acetate, the plasticizer such as the sugar ester and the polycondensation ester, and adjusting the film thickness, The bending process is repeated 50 times or more and less than 120 times in the bending process in which the B side opposite to the A side of the web is alternately inwardly bent by the conveying rollers in the dryer zone within the range of It can be understood that it is possible to adjust within the range of the rate of change.

It can be seen from Table 1 that the polarizing plate using Film A and Film B adjusted within the range of the dimensional change rate of the present invention exhibits deterioration in polarizer adhesion such as display irregularity of the liquid crystal panel, It is apparent that a polarizing plate which does not exhibit a polarizing plate can be obtained. In particular, it has been found that a polarizing plate which does not exhibit deterioration in polarizer adhesion such as crying phenomenon and film peeling can be obtained even when a cycle test is conducted under a severe temperature and humidity condition which is not conventionally known.

The polarizing plate using the dope of Film B and the B-137 and B-138 obtained by changing the dope 7 and the dope 8 not containing the retardation adjusting agent to B-132 to B-136 using Dope 2 to Dope 6 There was no practical problem as compared with the polarizing plate used, but the visibility (contrast) was slightly lowered.

Example 2

In the production of the film A-104 and the film B-104 of Example 1, the cooling rate was changed in the film A, and the drying temperature and the number of times of bending in the film B were changed to obtain L ₃₀ MD, L _The films A-201 to A-204 and the films B-201 to B-204 having a value of ₃₀ TD were produced and a polarizing plate was produced in the same manner as in Example 1 to evaluate display unevenness and polarizer adhesion .

The results are shown in Table 3.

From Table 3, it is understood that when the L ₃₀ TD and the L ₃₀ MD of the film A and the film B are within the range of -0.10 to 0.10%, the display irregularity of the liquid crystal panel, It can be seen that a more excellent polarizing plate in which the deterioration of polarizer adhesion such as peeling does not occur can be obtained.

Example 3

[Film A-301: (TAC / acrylic resin 2 / TAC) film and film A-302: (TAC / acrylic resin 3 / TAC)

A three-layered film A-301 of (TAC / acrylic resin 2 / TAC) and a film A-301 of (TAC / acrylic resin 2 / TAC) were produced by the three- / Acrylic resin 3 / TAC) having a three-layer structure.

(Preparation of Dope 9)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The resulting solution was filtered through an Azumi Rosy No.24 manufactured by Azumi Co., Ltd. to obtain a main dope 9.

<Composition of main doping 9>

Acrylic resin 2: Dianal BR88 (manufactured by Mitsubishi Rayon Co., Ltd., acrylic resin Mw: 1.5 million) 90 parts by mass

Sugar ester: BzSc benzyl saccharose: mixture of compounds a-1 to a-4 described in formula (3)), average ester substitution degree = 5.5 10 parts by mass

Methylene chloride 360 parts by mass

ethanol 15 parts by mass

100 parts by mass of the main dope 9 and 2.5 parts by mass of the inline addition liquid prepared as the film A in Example 1 were thoroughly mixed with an inline mixer (Toray static mixer Hi-Mixer, SWJ) to obtain Dope 9.

(Preparation of Dope 10)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The obtained solution was filtered through an Azumirosi No.24 manufactured by Azumi Co., Ltd. to obtain a main dope 10.

<Composition of main doping 10>

Acrylic resin 3: A (meth) acrylic resin having a lactone ring structure in which R ¹ is a hydrogen atom and R ² and R ³ are methyl groups, represented by the formula (1) described in JP-A-2009-157352 : Methyl methacrylate / 2- (hydroxymethyl) methyl acrylate = 8/2; 90 parts by mass of acrylonitrile-styrene (about 100% of lactone conversion) and 10 parts by mass of acrylonitrile-styrene (AS) resin (Toy AS AS20, Toyo Styrene Co., Ltd.)

Sugar ester: BzSc benzyl saccharose: mixture of compounds a-1 to a-4 described in formula (3)), average ester substitution degree = 5.5 10 parts by mass

Methylene chloride 360 parts by mass

ethanol 15 parts by mass

100 parts by mass of the main dope 10 and 2.5 parts by mass of the inline addition liquid prepared as the film A in Example 1 were sufficiently mixed with an inline mixer (Toray stationary type in-line mixer Hi-Mixer, SWJ) to obtain Dope 10.

(Preparation of Dope 11)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The obtained solution was filtered through an Azumirosi No.24 manufactured by Azumi Co., Ltd. to obtain a main dopant 11.

<Composition of main doping 11>

Triacetyl cellulose (TAC: acetyl group degree of substitution 2.80, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 86 parts by mass

Polyhydric alcohol ester (compound represented by formula (2)): Exemplary compound 2-10

2 parts by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 7 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P1 5 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

100 parts by mass of the main dope 11 and 2.5 parts by mass of the inline addition liquid prepared for the film B in Example 1 were thoroughly mixed with an inline mixer (Toray static mixer Hi-Mixer, SWJ) to obtain Dope 11.

(Film forming step)

The dope 11 is used as a skin layer (B side), the dope 9 is used as a core layer and the dope 9 is used as a skin layer (A) as a skin layer (B side) from the side of the endless belt 16 as a flexible metal support shown in Fig. 8 by using the dope 9 and the dope 11. [ The dope 11 is simultaneously supplied to the shared stretching die 10 and the flexible film 20 which is a laminate composed of the skin layer (B side) / the core layer / the skin layer (A side) Was supplied onto the endless belt (16). The supply amount of each dope was set such that the film thickness of each layer after final drying was 3 mu m / 30 mu m / 3 mu m for the skin layer (B side) / core layer / skin layer (A side).

On the flexible metal support, the organic solvent in the obtained dope was evaporated to a residual solvent amount of 100% by mass to form a web, followed by peeling off the web from the stainless steel band support. The obtained web was further preliminarily dried at 110 DEG C for 10 minutes, and then the web was drawn in a tenter at a temperature of 160 DEG C to 1.3 times the original width in the TD direction. The amount of residual solvent in the web at the start of the stretching was 2.0% by mass. After being stretched by a tenter, the film was relaxed at 130 占 폚 for 5 minutes and then conveyed at 130 占 폚 for 15 minutes by a dryer (bending zone 106) shown in Fig. 9, min to 23 &lt; 0 &gt; C. The resulting film was slit at a width of 2.0 m and knurled at both ends of the film to a width of 10 mm and a height of 5 탆 and wound around a core of 15.24 cm in inner diameter at an initial tension of 220 N / m and a final tension of 110 N / m, A film A-301 having a long three-layer structure of 36 mu m was obtained. Similarly, a film A-302 having a three-layer structure was obtained by using Dope 10 as a core layer and Dope 11 as a skin layer.

[Film A-303: Production of (acrylic resin 1 / cellulose ester) film]

(Preparation of Dope 12)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The resulting solution was filtered through an Azumi Rosy No.24 manufactured by Azumi Co., Ltd. to obtain a main doping 12.

Acrylic resin 1: Dianal BR85 (manufactured by Mitsubishi Rayon Co., Ltd., acrylic resin Mw: 280000) 70 parts by mass

Cellulose ester (cellulose acetate propionate acyl group total substitution degree 2.75, acetyl group substitution degree 0.19, propionyl group substitution degree 2.56, Mw = 200000, CAP in the table) 30 parts by mass

The acrylic fine particles (C1) 2 parts by mass

Methylene chloride 300 parts by mass

ethanol 40 parts by mass

&Lt; Production of acrylic fine particles (C1) >

38.2 liters of ion-exchanged water and 111.6 g of sodium dioctylsulfosuccinate were charged into a reactor equipped with a reflux condenser having an internal volume of 60 liters and the temperature was raised to 75 DEG C under a nitrogen atmosphere while stirring at a rotational speed of 250 rpm, It was virtually absent. 0.36 g of ammonium persulfate (APS) was added, and after stirring for 5 minutes, 1657 g of methyl methacrylate (MMA), 21.6 g of n-butyl acrylate (BA) and 1.68 g of allyl methacrylate The monomer mixture was added all at once, and after the exothermic peak was detected, the polymerization was continued for 20 minutes to complete the polymerization of the innermost hard layer.

Subsequently, 3.48 g of APS was added, and after stirring for 5 minutes, a monomer mixture containing 8105 g of BA, 31.9 g of polyethylene glycol diacrylate (PEGDA: molecular weight 200) and 264.0 g of ALMA was continuously added over 120 minutes After completion of the addition, the mixture was further maintained for 120 minutes to complete the polymerization of the soft layer.

Subsequently, 1.32 g of APS was added and stirred for 5 minutes. Thereafter, a monomer mixture containing 2106 g of MMA and 201.6 g of BA was continuously added over a period of 20 minutes. After completion of the addition, the mixture was further maintained for 20 minutes to obtain an outermost hard layer 1 The polymerization was completed.

Subsequently, 1.32 g of APS was added, and after 5 minutes, a monomer mixture containing 3148 g of MMA, 201.6 g of BA and 10.1 g of n-OM was continuously added over 20 minutes, and after the addition was completed, Respectively. Subsequently, the temperature was raised to 95 캜 and maintained for 60 minutes to complete the polymerization of the outermost hard layer 2.

A small amount of the polymer latex thus obtained was sampled and the average particle diameter was determined by the absorbance method. The result was 0.10 탆. The remaining latex was added to a 3 mass% sodium sulfate hot water solution, followed by salting out and solidifying, followed by dehydration and washing repeatedly, followed by drying to obtain acrylic fine particles (C1) having a three-layer structure.

100 parts by mass of the main dope 12 and 2.5 parts by mass of the inline additive liquid prepared as the film A in Example 1 were thoroughly mixed with an inline mixer (Toray static mixer Hi-Mixer, SWJ) to obtain Dope 12.

(Film forming step)

The resultant Dope 12 was used in the same manner as in the production of the film A-101 of Example 1, and on the stainless steel band support using a belt softener, under the conditions of a liquid temperature of 35 ° C and a width of 1.7 m, And uniformly plied under the condition that the thickness became 40 탆. On the stainless steel band support, the organic solvent in the obtained dope film was evaporated to a residual solvent amount of 100% by mass to form a web, and then the web was peeled from the stainless band support. The obtained web was preliminarily dried at 110 캜 for 10 minutes, and then the web was stretched 1.5 times with respect to the original width in the TD direction at 160 캜 in a tenter. The amount of residual solvent in the web at the start of the stretching was 2.0% by mass. After being stretched by a tenter, the film was relaxed at 130 占 폚 for 5 minutes and then conveyed at 130 占 폚 for 15 minutes by a dryer (bending zone 106) shown in Fig. 9, min to 23 &lt; 0 &gt; C. The resulting film was slit at a width of 2.0 m and knurled to 10 mm in width and 5 탆 in height at both ends of the film and wound around a core of 15.24 cm in inner diameter at an initial tension of 220 N / m and a final tension of 110 N / m, A film A-303 containing a long acrylic resin of 40 mu m was obtained.

Polarizers 301, 302, and 303 were produced using the film B-111, which was the film A-301, the film A-302, and the film B opposite to the A-303.

Using the prepared polarizing plates 301, 302, and 303, the evaluation conditions of Example 1 were changed to the following evaluation conditions.

(Evaluation of display unevenness)

The resulting liquid crystal display device was allowed to stand in a constant temperature and humidity bath at 50 占 폚 and 90% RH for 1 hour and then allowed to stand in a temperature and humidity environment of 23 占 폚 and 55% RH for 1 hour to make one cycle. After repeating this cycle for 10 times, The difference between the luminance near the four vertexes of the display screen and the luminance near the center of the display screen (display unevenness) was visually observed while the liquid crystal display device was displayed in black. The display unevenness was evaluated based on the following criteria. In the following evaluation,? And? Are preferable.

A: No display irregularity at all

○: slight noticeable irregularity is observed with very fine attention

△: display irregularity appears at one of four vertices

×: Display irregularity is observed at three or more of four vertices

(Evaluation of Polarizer Adhesion)

The obtained liquid crystal display was allowed to stand in a constant temperature and humidity bath at 80 占 폚 and 90% RH for 1 hour and then allowed to stand for 1 hour under a 23 占 폚 and 55% RH temperature and humidity environment. Crying phenomenon and film peeling were observed, and adhesion between the film A and the film B and the polarizer was evaluated.

◎: There is no crying phenomenon or film peeling at the surface of the panel.

○: When very careful attention is paid, the surface of the panel is slightly crying

?: Apparently crying appears on the surface of the panel, but no peeling occurs

X: Crying phenomenon and film peeling were observed on the surface of the panel

The results are shown in Table 4.

From Table 4, it can be seen from Table 4 that even if the film A is made into a three-layered film using TAC in the skin layer, such as (TAC / acrylic resin / TAC) film, even if the temperature and humidity environment of the use environment changes under more severe conditions, It can be seen that a more excellent polarizing plate is obtained which does not exhibit deterioration in polarizer adhesion such as unevenness, crying phenomenon, film peeling, and the like. In addition, the liquid crystal panel using the film having the three-layer structure also improved warping of the panel. Also, a film having the same structure as A-303 obtained by mixing acrylic resin and cellulose ester was excellent in polarizer adhesion such as display unevenness of liquid crystal panel, crying phenomenon, film peeling and the like.

Example 4

Film A-401 to Film A-404 were produced by changing the draw ratio in the TD direction as shown in Table 5 in the production of Film A-104 of Example 1, and using Film B-104 as the opposite film B Polarizing plates 401 to 404 were fabricated, and the display unevenness and the polarizer adhesion were evaluated in the same manner as in Example 1. [

The results are shown in Table 5.

It can be seen from Table 5 that the film A is stretched within the range of 1.05 to 1.5 times the original width in the TD direction so that even if the temperature and humidity environment of the use environment is changed, the polarity of polarizers such as display unevenness, It can be seen that a more excellent polarizing plate in which the deterioration of the adhesion property does not appear can be obtained.

Example 5

The film B-501 to the film B-505 having the retardation values shown in Table 6 were produced by changing the stretching magnification in the TD direction within the range of 1.05 to 1.4 times in the production of the film B-104 of Example 1 Polarizing plates 501 to 505 were produced using Film A-104 as the opposite film A, and the display unevenness and the polarizer adhesion were evaluated in the same manner as in Example 1. [ The retardation was measured by the above-mentioned method.

The results are shown in Table 6.

It can be seen from Table 6 that the values of the retardation values Ro and Rt can be adjusted within the preferred range of the present invention by stretching the film B in the TD direction and even if the temperature and humidity environment of the use environment changes, It can be seen that a more excellent polarizing plate is obtained which does not exhibit deterioration in polarizer adhesion such as unevenness, crying phenomenon, film peeling, and the like.

Example 6

[Film B-601: (TAC / DAC2 / TAC) film and film B-602: (TAC / DAC3 / TAC)

Using the shared stretching die shown in Fig. 8, films B-601 and (TAC / DAC3) having a three-layer structure (TAC / DAC2 / TAC) / TAC) having a three-layer structure.

(Preparation of Dope 13)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The obtained solution was filtered through an Azumirosi No.24 manufactured by Azumi Co., Ltd. to obtain a main dop 13.

<Composition of main doping 13>

Diacetyl cellulose 2 (acetyl group degree of substitution: 2.40, Mn = 80000, Mw = 136000, Mw / Mn = 1.7) 86 parts by mass

Compound E-104 described in JP-A-2012-215817 2 parts by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 7 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P1 5 parts by mass

Dichloromethane 30 parts by mass

ethanol 11 parts by mass

100 parts by mass of the main dope 13 and 2.5 parts by mass of the inline additive liquid prepared for the film B in Example 1 were sufficiently mixed with an inline mixer (Toray stationary type in-line mixer Hi-Mixer, SWJ) to obtain Dope 13.

(Preparation of Dope 14)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The obtained solution was filtered through an Azumirosi No.24 manufactured by Azumi Co., Ltd. to obtain a main doping 14. [

<Composition of main doping 14>

Diacetyl cellulose 3 (acetyl group degree of substitution: 2.20, Mn = 100000, Mw = 170000, Mw / Mn = 1.7) 86 parts by mass

The compound E-203 described in JP-A-2012-215817 2 parts by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 7 parts by mass

Polycondensation ester: polycondensation ester represented by the formula (1): P8 5 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

100 parts by mass of the main dope 14 and 2.5 parts by mass of the inline addition liquid prepared for the film B in Example 1 were thoroughly mixed with an inline mixer (Toray static mixer Hi-Mixer, SWJ) to obtain Dope 14.

(Film forming step)

The dope 11 was used as the skin layer (B side) from the side of the endless belt 16 as the flexible metal support shown in Fig. 8 and the dope 13 (B side) / core layer / skin layer (A side) by a single smoothing operation by supplying the dope 11 as a skin layer (A side) to the shared softening die 10 at the same time The flexible film 20 as a laminate was fed onto the endless belt 16. The supply amount of each dope was set such that the film thickness of each layer after final drying was 3 mu m / 30 mu m / 3 mu m for the skin layer (B side) / core layer / skin layer (A side).

On the flexible metal support, the organic solvent in the obtained dope was evaporated to a residual solvent amount of 100% by mass to form a web, followed by peeling off the web from the stainless steel band support. The obtained web was preliminarily dried at 110 캜 for 10 minutes, and then the web was drawn in a tenter at 1.3 캜 with respect to the original width in the TD direction at 160 캜. The amount of residual solvent in the web at the start of the stretching was 2.0% by mass. After being stretched by a tenter, the sheet was relaxed at 130 占 폚 for 5 minutes. Thereafter, the sheet was held at a temperature of 135 占 폚 by a dryer (bending zone 106) shown in Fig. 9, The diameter and the arrangement of the conveying rollers are set such that the value of 1 / a is 0.040 mm &lt; ^-1 &gt; when a (mm) represents a radius when the B side opposite to the A side of the web is alternately bent inward And the web was conveyed at a conveyance speed of 20 m / minute by repeating bending for 80 times.

The resultant film was slit at a width of 2.0 m and knurled at both ends of the film to a thickness of 10 mm and a height of 5 탆 and wound around a core of 15.24 cm in inner diameter at an initial tension of 220 N / m and a final tension of 110 N / m, A film B-601 having a long three-layer structure with a thickness of 40 mu m was obtained. Similarly, a film B-602 having a three-layer structure was obtained by using Dope 14 as a core layer and using Dope 11 as a skin layer.

Using the following Dope 15, a single film B-603 containing diacetyl cellulose was produced in the same manner as the film B-116 of Example 1.

(Preparation of Dope 15)

The following components were put in a hermetically sealed container and completely dissolved by heating and stirring. The resulting solution was filtered through an Azumi Rosy No.24 manufactured by Azumi Co., Ltd. to obtain a main dop 15.

&Lt; Composition of main dop 15 >

Diacetylcellulose 1 (acetyl group degree of substitution: 2.35, Mn = 90000, Mw = 152000, Mw / Mn = 1.7) 83 parts by mass

Sugar esters; BzSc (Benzyl Saccharose: a mixture of Compounds a-1 to a-4 described in Formula 3), average ester substitution degree = 5.5 7 parts by mass

The polycondensation ester: The polycondensation ester P8 represented by the formula (1) 5 parts by mass

Retardation modifier 1 3 parts by mass

Additive A 2 parts by mass

Dichloromethane 430 parts by mass

ethanol 11 parts by mass

100 parts by mass of the main dope 15 and 2.5 parts by mass of the inline addition liquid prepared for the film B in Example 1 were thoroughly mixed with an inline mixer (Toray stationary in-line mixer Hi-Mixer, SWJ) to obtain Dope 15.

Polarizing plates 601 to 603 were produced using Film A-116 for Film A, which was opposite to Film B-601, Film B-602 and Film B-603 produced.

Using the prepared polarizing plates 601 to 603, evaluation of the display unevenness and the polarizer adhesion was carried out according to the evaluation conditions of Example 3.

The results are shown in Table 7.

From Table 7, it can be seen from Table 7 that even if the film B is made into a film having a three-layer structure using TAC in the skin layer such as a (TAC / DAC / TAC) film, It can be seen that an excellent polarizing plate is obtained in which deterioration of polarizer adhesion such as uneven display of liquid crystal panel, crying phenomenon, film peeling is not observed.

Example 7

Polarizers were produced by changing the film thickness of the polarizer as shown in Table 7 in the production of the polarizing laminated film used in Example 1 and polarizing plates 701 to 705 were fabricated with the polarizing plate 117 of Example 1.

In order to observe the difference in polarizer, a conventional polyvinyl alcohol (PVA) film shown below was subjected to stretching treatment to prepare a polarizer, and similarly, a polarizing plate 706 was produced.

(Production of Polarizer 2)

A polyvinyl alcohol (PVA) film having a thickness of 45 탆 was swelled with water at 35 캜. The obtained film was immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds and immersed in an aqueous solution at 45 캜 containing 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water. The resulting film was uniaxially stretched under the conditions of a stretching temperature of 55 캜 and a draw ratio of 5. The uniaxially stretched film was washed with water and then dried to obtain a polarizer having a thickness of 9 탆.

Using the polarizing plates 701 to 706 thus prepared, evaluation of the display unevenness and the polarizer adhesion was carried out according to the evaluation conditions of Example 1.

The results are shown in Table 8.

It can be seen from Table 8 that even if the temperature and humidity environment of the use environment is changed by using a polarizer which is a polarizing film of a polarizing laminated film type and a film thickness of 2 to 15 占 퐉, unevenness of display on a liquid crystal panel, It is possible to obtain a better polarizing plate in which deterioration of the polarizer adhesion of the polarizing plate is not observed. Further, it can be seen that a polarizing plate superior in polarizer adhesion such as display unevenness of liquid crystal panel, crying phenomenon, film peeling and the like can be obtained as compared with a polarizer obtained by stretching a conventional polyvinyl alcohol (PVA) film.

[Possibility of industrial use]

The polarizing plate of the present invention has a polarizing plate using an acrylic film and a cellulose ester film as a protective film of a polarizer when the liquid crystal display device is provided with a liquid crystal display panel having a display unevenness, Is not suitably used for a liquid crystal display device or the like, and is particularly suitable for VA mode liquid crystal display devices.

1: melting furnace 3, 6, 12, 15: filter
4, 13: Stock kiln 5, 14: Pump pump
8, 16: conduit 10: ultraviolet absorber input kiln
20: confluent tube 21: mixer
30: pressure die 31: metal belt
32: Web 33: Peeling position
34: Tenter stretching device 35: Drying device
41: Feeding kiln 42: Stock kiln
43: Pump 44: Filter
50: Shared softening die 51:
53, 55: layer B, slit for layer C 54: slit for layer A
56: metal support 57, 59: layer B, layer C doping
58: layer A doping 60: multi-layer web
61: layer C (skin layer) 62: layer A (core layer)
63: layer B (skin layer) 100: dice
102: metal support 103: drive roller
104: peeling point 105: conveying roller
106: bending zone 107: intake port
108: exhaust port 109: cooling zone

Claims (17)

A polarizer comprising a polarizer sandwiched between a film A and a film B via an active ray curable adhesive layer,
Wherein the film A is an acrylic film containing an acrylic resin and having a film thickness in a range of 20 to 60 탆 and satisfying the following formulas (1) to (4)
Wherein the film B contains cellulose acetate having a film thickness in the range of 20 to 60 占 퐉 and an average degree of acetyl group substitution in the range of 2.0 to 2.5 and satisfying the following formulas (1) to (4) Wherein the polarizer is an acetate film.
(1) 0.03 (%)? L ₁ MD-L ₅ MD? 0.30 (%)
(2) 0.03 (%)? L ₁ TD-L ₅ TD? 0.30 (%)
(3) 0 (%)? L ₅ MD-L ₃₀ MD? 0.10 (%)
(4) 0 (%)? L ₅ TD-L ₃₀ TD? 0.10 (%)
In the above formula, L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD satisfy the following equations (a) to (f) Of the film after a minute. The following formulas (a) to (f) show the film A and the film B taken in a rectangle so that one side is parallel to the TD direction or the MD direction, and the film A and the film B are left for 24 hours under a temperature and humidity environment of 23 캜 and 55% The predetermined dimensions are measured in the MD direction and the TD direction, and are referred to as L ₀ MD and L ₀ TD, respectively. The film was allowed to stand in a constant temperature and humidity bath at 80 占 폚 and 90% RH for 1 hour and left under a temperature and humidity environment of 23 占 폚 and 55% RH. The dimensions after one minute, the dimensions after five minutes, respectively measured in the TD direction, respectively, _{L 1 MD ', L 1 TD} ', L 5 MD ', L 5 TD', L 30 MD ', and L ₃₀ TD' La, and the following formula (a) to (f) And the dimensional change rate is obtained.
Dimensional change rate after 1 minute
(Formula 1) L ₁ MD (%) = (L ₁ MD '- L ₀ MD) / L ₀ MD × 100
(Expression b) L ₁ TD (%) = (L ₁ TD'-L ₀ TD) / L ₀ TD × 100
Dimensional change rate after 5 minutes
(C) L ₅ MD (%) = (L ₅ MD'-L ₀ MD) / L ₀ MD x 100
(Formula d) L ₅ TD (%) = (L ₅ TD'-L ₀ TD) / L ₀ TD x 100
Dimensional change rate after 30 minutes
L ₃₀ MD (%) = (L ₃₀ MD'-L ₀ MD) / L ₀ MD x 100
(Formula f) L ₃₀ TD (%) = (L ₃₀ TD'-L ₀ TD) / L ₀ TD x 100 The method according to claim 1,
Wherein the film A and the film B satisfy the following formulas (5) to (8), respectively.
(5) 0.05 (%)? L ₁ MD-L ₅ MD? 0.15 (%)
(6) 0.05 (%)? L ₁ TD-L ₅ TD? 0.15 (%)
(7) 0 (%)? L ₅ MD-L ₃₀ MD? 0.05 (%)
(8) 0 (%)? L ₅ TD-L ₃₀ TD? 0.05 (%)
In this equation, L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD are synonymous with the first term. 3. The method according to claim 1 or 2,
Wherein L ₃₀ TD and L ₃₀ MD of the film A and the film B are within a range of -0.10 to 0.10%, respectively. 4. The method according to any one of claims 1 to 3,
Wherein the film A contains a sugar ester or a polycondensation ester having a structure represented by the following formula (1).
(1)

(Wherein B ₃ and B ₄ each independently represent an aliphatic or aromatic monocarboxylic acid residue or a hydroxyl group, G ₂ represents an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol having 6 to 12 carbon atoms Or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n is an integer of 1 or more Represents an integer.) 5. The method according to any one of claims 1 to 4,
Wherein the film A comprises at least three layers each having a skin layer on both sides of the core layer, the core layer contains an acrylic resin, and the skin layer contains a cellulose ester. 6. The method according to any one of claims 1 to 5,
Wherein the film A is stretched in the range of 1.05 to 1.5 times the original width in the TD direction. 7. The method according to any one of claims 1 to 6,
The retardation value Ro in the in-plane direction defined by the following formulas (i) and (ii) is in the range of 40 to 60 nm and the retardation value Rt in the thickness direction is in the range of 100 to 140 nm Wherein the polarizer is a polarizer.
Formula (i): Ro = (n x -n y) × d (nm)
Formula (ii): Rt = {( n x + n y) / 2-n z} × d (nm)
[In the formulas (i) and (ii), n _x represents the refractive index in the direction x at which the refractive index becomes maximum in the in-plane direction of the film. n _y represents a refractive index in an in-plane direction of the film and in a direction y perpendicular to the direction x. and n _z represents the refractive index in the thickness direction z of the film. and d represents the thickness (nm) of the film. Measurement is carried out at a measurement wavelength of 590 nm under an environment of 23 ° C and 55% RH.] 8. The method according to any one of claims 1 to 7,
Wherein said film B contains cellulose acetate having an acetyl group average degree of substitution in the range of 2.1 to 2.4. 9. The method according to any one of claims 1 to 8,
Characterized in that the film B contains a sugar ester or a polycondensation ester having a structure represented by the following formula (1).
(1)

(Wherein, B ₃ and B ₄ are each independently an aliphatic or aromatic mono-carboxylic acid residue, or a hydroxy. G ² is alkylene having 2 to 12 glycol residue, an aryl glycol residue having 6 to 12 carbon atoms Or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n is an integer of 1 or more Lt; / RTI &gt; 10. The method according to any one of claims 1 to 9,
Wherein the film B comprises at least three layers each having a skin layer on both sides of the core layer and the core layer contains cellulose acetate having an acyl group degree of substitution in the range of 2.0 to 2.45 and the skin layer has an acyl group substitution degree Has a cellulose acetate content in the range of 2.6 to 2.95. 11. The method according to any one of claims 1 to 10,
Wherein the polarizer has a thickness in the range of 2 to 15 占 퐉. A polarizing plate manufacturing method for bonding a film A and a film B to both sides of a polarizer through an active line curable adhesive layer,
As the film A, an acrylic film containing an acrylic resin having a film thickness in the range of 20 to 60 탆 and satisfying the following formulas (1) to (4) was used,
Wherein the film B contains cellulose acetate having a film thickness in the range of 20 to 60 占 퐉 and an average degree of acetyl group substitution in the range of 2.0 to 2.5 and satisfying the following formulas (1) to (4) Acetate film is used as the polarizing plate.
(1) 0.03 (%)? L ₁ MD-L ₅ MD? 0.30 (%)
(2) 0.03 (%)? L ₁ TD-L ₅ TD? 0.30 (%)
(3) 0 (%)? L ₅ MD-L ₃₀ MD? 0.10 (%)
(4) 0 (%)? L ₅ TD-L ₃₀ TD? 0.10 (%)
In the above formula, L ₁ MD, L ₁ TD, L ₅ MD, L ₅ TD, L ₃₀ MD and L ₃₀ TD satisfy the following equations (a) to (f) Of the film after a minute. The following formulas (a) to (f) show the film A and the film B in a rectangular shape so that one side is parallel to the TD direction or the MD direction, and the film A and the film B are left for 24 hours under a temperature and humidity environment of 23 캜 and 55% Dimensions are measured in the MD and TD directions and are referred to as L ₀ MD and L ₀ TD, respectively. The film was allowed to stand in a constant temperature and humidity bath at 80 占 폚 and 90% RH for 1 hour and left under a temperature and humidity environment of 23 占 폚 and 55% RH. The dimensions after one minute, the dimensions after five minutes, respectively measured in the TD direction, respectively, _{L 1 MD ', L 1 TD} ', L 5 MD ', L 5 TD', L 30 MD ', and L ₃₀ TD' La, and the following formula (a) to (f) And the dimensional change rate is obtained.
Dimensional change rate after 1 minute
(Formula 1) L ₁ MD (%) = (L ₁ MD '- L ₀ MD) / L ₀ MD × 100
(Expression b) L ₁ TD (%) = (L ₁ TD'-L ₀ TD) / L ₀ TD × 100
Dimensional change rate after 5 minutes
(C) L ₅ MD (%) = (L ₅ MD'-L ₀ MD) / L ₀ MD x 100
(Formula d) L ₅ TD (%) = (L ₅ TD'-L ₀ TD) / L ₀ TD x 100
Dimensional change rate after 30 minutes
L ₃₀ MD (%) = (L ₃₀ MD'-L ₀ MD) / L ₀ MD x 100
(Formula f) L ₃₀ TD (%) = (L ₃₀ TD'-L ₀ TD) / L ₀ TD x 100 13. The method of claim 12,
The film (A)
A step of forming a web on a metal support by softening at least a dope containing an acrylic resin and an organic solvent,
Drying the formed web to separate it from the metal support,
A step of stretching the peeled web;
Drying the elongated web in a dryer zone,
And a cooling step of cooling the web at a speed in a range of 50 to 100 DEG C / sec after the web leaves the dryer zone
Wherein the polarizing plate is formed of a polarizing plate. The method according to claim 12 or 13,
The film (B)
A step of forming a web on a metal support by softening a dope containing at least cellulose acetate and an organic solvent,
Drying the formed web to separate it from the metal support,
A step of stretching the peeled web;
A step of drying the elongated web in a dryer zone
, The step of drying the web in the dryer zone is maintained at a temperature within the range of 130 to 150 DEG C and the B side opposite to the A side of the web is alternately turned inwardly by the conveying roller when the bending radius of a La (mm) at the time went off this has a bending process, the art bending process, the bend art web, and the value of 1 / a in the range of 0.035mm to 0.050mm ^{-1 -1,} also Wherein the bending is repeated 50 times or more and less than 120 times. 15. The method according to any one of claims 12 to 14,
A step of forming a polyvinyl alcohol-based resin layer on one surface of a base film in which a rubber component is dispersed in a thermoplastic resin to obtain a laminated film,
A step of uniaxially stretching the laminated film to obtain a stretched film,
A step of staining the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to obtain a dye film,
A step of immersing the polyvinyl alcohol-based resin layer of the dye film in a solution containing a crosslinking agent to form a polarizer layer to obtain a crosslinked film;
A step of drying the crosslinked film
To form a polarizing laminated film,
And peeling the polyvinyl alcohol-based resin layer of the polarizing laminated film from the base film to use the polyvinyl alcohol-based resin layer as the polarizer. A liquid crystal display device comprising the polarizing plate according to any one of claims 1 to 11. 17. The method of claim 16,
Wherein the liquid crystal display device is a VA mode liquid crystal display device.

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