JP2018018096A - Optical film, polarizing plate, and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate with small humidity expansion suitable for producing a high quality liquid crystal display, and an optical film used for the same.SOLUTION: An optical film is made of acrylic resin. The optical film has a tensile elastic modulus (EMD) in a machine direction (MD direction) and a tensile elastic modulus (ETD) in a direction perpendicular to the machine direction (TD direction) satisfying relation of a formula (1). Formula (1): EMD/ETD<0.8.SELECTED DRAWING: None

Description

  The present invention relates to an optical film, a polarizing plate, and a liquid crystal display device.

  Liquid crystal display devices have low power consumption and are increasingly used year by year as space-saving image display devices. Wide viewing angle liquid crystal modes such as VA mode and IPS mode have been put into practical use, and as a result, the demand for liquid crystal display devices is rapidly expanding even in markets where high-quality images such as televisions are required.

  As the application of liquid crystal display devices has been expanded, it has been required to achieve both large size and high quality texture for liquid crystal display devices. The liquid crystal display device has a liquid crystal cell and polarizing plates provided on the viewing side (front side) and the backlight side (rear side) of the liquid crystal cell. Both polarizing plates are attached to both surfaces of the liquid crystal cell substrate with an adhesive or the like. It is attached.

A polarizing plate used in a liquid crystal display device generally has a configuration in which a polarizer made of a polyvinyl alcohol film or the like on which iodine or a dye is adsorbed and oriented, and a transparent optical film as a protective film are bonded to both sides of the polarizer. ing.
Patent Document 1 discloses a polarizing plate using an acrylic film on one side of a polarizer and a cellulose acylate film on the other side as a protective film for the polarizer.
A mixed film of an acrylic resin and a cellulose ester resin is also disclosed in Patent Documents 2 and 3.

JP 2009-292869 A JP 2009-265365 A JP 2012-008417 A

A general polarizing plate is composed of a polyvinyl alcohol polarizer and an optical film. The polyvinyl alcohol polarizer is uniaxially stretched after iodine staining, and the stretching direction is the absorption axis. As a result of intensive studies, the present inventors have found that the polarizer easily absorbs and expands in the direction perpendicular to the stretching direction of the polarizer.
The present inventors have studied a mixed film of an acrylic resin and a cellulose ester resin. However, the moisture permeability is large, the hygroscopic expansion of the polarizer due to the water that has passed through the film, and the hygroscopic expansion of the film itself. It was large and found further improvement. It has also been clarified that display unevenness due to the photoelasticity of the optical film is likely to occur.

The hygroscopic expansion of the polarizing plate becomes a problem in the step of attaching the polarizing plate to the liquid crystal cell. Since the polarizing plate is sealed in the moisture-proof bag after the high-temperature drying step (drying temperature 60 ° C. to 80 ° C.), the polarizing plate is stored in a dry state. The step of attaching the polarizing plate to the liquid crystal cell is performed in a high humidity environment (temperature 15 ° C. to 30 ° C., relative humidity 50% to 65%) in order to suppress the generation of static electricity. Therefore, the polarizing plate opened from the moisture-proof bag during the bonding process is hygroscopically expanded, and is bonded to the liquid crystal cell in a state where the polarizing plate is hygroscopically expanded.
Due to the hygroscopic expansion of the polarizing plate in the direction perpendicular to the stretching direction of the polarizer, the polarizing plate expands according to the humidity difference between the step of attaching the polarizing plate to the liquid crystal cell and the usage environment of the liquid crystal display device, The relative position of the polarizing plate changes. The liquid crystal display device has a portion corresponding to a frame called a bezel at the periphery of the screen. The bezel has a role of aesthetically finishing the display device by hiding the end of the polarizing plate. In order to achieve both an increase in size and a high-quality texture of a liquid crystal display device, the bezel is becoming narrower, and accordingly, the gap between the glass end and the polarizing plate is becoming narrower. Therefore, the problem that the end portion of the polarizing plate protrudes from the end portion of the glass due to hygroscopic expansion of the polarizing plate is likely to occur.

  An object of the present invention is to provide a polarizing plate with small humidity expansion and an optical film used therefor that are suitable for the production of a high-quality liquid crystal display device.

As a result of the study by the present inventors, it is very effective to suppress the hygroscopic expansion of the polarizing plate by using an optical film having mechanical properties that are rigid with respect to the direction orthogonal to the stretching direction of the polarizer. I got the knowledge. More specifically, an optical component made of an acrylic resin and having a ratio value obtained by dividing the tensile modulus in the machine direction (MD direction) by the tensile modulus in the direction perpendicular to the machine direction (TD direction) is less than 0.8. It has been found that by disposing the film on one side or both sides of the polarizer, the humidity expansion of the polarizer is greatly reduced and a good polarizing plate can be obtained.
The cause of the dependence of the elastic modulus on the anisotropy has not been fully clarified, but it is considered that the anisotropy of the elastic modulus is related to the degree of orientation of the polymer chains constituting the acrylic resin. Therefore, it is presumed that the optical film oriented in the TD direction has a high elastic modulus in the TD direction, thereby suppressing the expansion in the TD direction caused by moisture absorption by the polarizer.
That is, the above problem can be solved by the following means.
<1>
Contains acrylic resin having lactone ring structure in main chain and acrylonitrile-styrene resin, tensile modulus (EMD) in machine direction (MD direction) and tensile modulus (ETD) in direction perpendicular to machine direction (TD direction) Is an optical film satisfying the relationship of the formula (1).
Formula (1) EMD / ETD <0.8
<2>
The tensile modulus in the machine direction (MD direction) of the optical film is 1.2 × 10 ^{9 to} 4.0 × 10 ⁹ N / m ² , and the tensile modulus in the direction perpendicular to the machine direction (TD direction) is The optical film according to <1>, which is 1.5 × 10 ^{9 to} 5.0 × 10 ⁹ N / m ² .
<3>
The retardation value Re (nm) in the film plane represented by the formulas (i) and (ii) of the optical film and the retardation value Rth (nm) in the film thickness direction are the formulas (iii) and (iv). <1> or <2> the optical film satisfying.
(I) Re = (nx−ny) × d
(Ii) Rth = ((nx + ny) / 2−nz) × d
(Iii) 0 ≦ Re <20
(Iv) | Rth | ≦ 25
In the formula, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the film (Nm).
<4>
At least one layer of a pattern retardation layer, a λ / 4 layer, a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, an optically anisotropic layer, and an easy adhesion layer is provided on the surface of the optical film <1. The optical film according to any one of> to <3>.
<5>
A polarizer and a polarizing plate having the optical film according to any one of <1> to <4> on at least one surface of the polarizer.
<6>
The polarizing plate as described in <5> which has the optical film of any one of <1>-<4> on both surfaces of a polarizer.
<7>
A liquid crystal display device having at least one polarizing plate according to <5> or <6>.
Although this invention is invention concerning said <1>-<7>, below, other matters are also described.

[1]
An optical film made of an acrylic resin, wherein the tensile modulus (EMD) in the machine direction (MD direction) and the tensile modulus (ETD) in the direction perpendicular to the machine direction (TD direction) satisfy the relationship of formula (1).
Formula (1) EMD / ETD <0.8
[2]
The tensile modulus in the machine direction (MD direction) of the optical film is 1.2 × 10 ^{9 to} 4.0 × 10 ⁹ N / m ² , and the tensile modulus in the direction perpendicular to the machine direction (TD direction) is The optical film according to [1], which is 1.5 × 10 ^{9 to} 5.0 × 10 ⁹ N / m ² .
[3]
The retardation value Re (nm) in the film plane represented by the formulas (i) and (ii) of the optical film and the retardation value Rth (nm) in the film thickness direction are the formulas (iii) and (iv). The optical film according to [1] or [2], which is satisfied.
(I) Re = (nx−ny) × d
(Ii) Rth = ((nx + ny) / 2−nz) × d
(Iii) 0 ≦ Re <20
(Iv) | Rth | ≦ 25
In the formula, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the film (Nm).
[4]
At least one layer of a pattern retardation layer, a λ / 4 layer, a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, an optically anisotropic layer, and an easy adhesion layer is provided on the surface of the optical film [1. ] The optical film in any one of [3].
[5]
The polarizing plate which has a polarizer and the optical film in any one of [1]-[4] on the single side | surface of a polarizer at least.
[6]
The polarizing plate as described in [5] which has the optical film in any one of [1]-[4] on both surfaces of a polarizer.
[7]
A liquid crystal display device having at least one polarizing plate according to [5] or [6].

  According to the present invention, it is possible to provide a polarizing plate with small humidity expansion and an optical film used therefor, which are suitable for manufacturing a high-quality liquid crystal display device.

  The optical film of the present invention is made of an acrylic resin.

The acrylic resin is a concept including a methacrylic resin, and includes acrylate / methacrylate derivatives, in particular, acrylate ester / methacrylate ester (co) polymers.
Further, the acrylic resin includes, in addition to the methacrylic resin, an acrylic resin having a ring structure in the main chain, a polymer having a lactone ring, a maleic anhydride polymer having a succinic anhydride ring, and an anhydrous glutar It includes a polymer having an acid ring and a glutarimide ring-containing polymer.
Further, “consisting of acrylic resin” means that the optical film contains 70% by mass or more of acrylic resin, preferably 80% by mass or more of acrylic resin, and more preferably 90% by mass of acrylic resin. Including at least%.

(Acrylic resin)
The repeating structural unit of the acrylic resin is not particularly limited. The acrylic resin preferably has a repeating structural unit derived from an acrylate monomer as a repeating structural unit.

The acrylate ester is not particularly limited, and examples thereof include acrylate esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, and benzyl acrylate. Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate and benzyl methacrylate; You may use only a seed | species and may use 2 or more types together. Among these, methyl methacrylate is particularly preferable from the viewpoint of excellent heat resistance and transparency.
When the acrylate ester is used as a main component, the content ratio in the monomer component to be subjected to the polymerization step is preferably 50 to 100% by mass, more preferably 70, in order to sufficiently exhibit the effects of the present invention. -100 mass%, More preferably, it is 80-100 mass%, Most preferably, it is 90-100 mass%.
It is preferable that the glass transition temperature Tg of the resin mainly composed of the acrylate ester is in the range of 80 to 120 ° C.
The weight average molecular weight of the resin mainly composed of the acrylate ester is preferably in the range of 50,000 to 500,000.

-Acrylic resin with a ring structure in the main chain-
Among acrylic resins, those having a ring structure in the main chain are preferred. By introducing a ring structure into the main chain, the rigidity of the main chain can be improved and the heat resistance can be improved.
In the present invention, among acrylic resins having a ring structure in the main chain, a polymer containing a lactone ring structure in the main chain, a maleic anhydride polymer having a succinic anhydride ring in the main chain, and a glutaric anhydride ring in the main chain It is preferably either a polymer having a structure or a polymer having a glutarimide ring structure in the main chain. Among them, a polymer having a lactone ring structure in the main chain and a polymer having a glutarimide ring structure in the main chain are more preferable.
The following polymers having a ring structure in these main chains will be described in order.

(1) Acrylic resin having a lactone ring structure in the main chain An acrylic resin having a lactone ring structure in the main chain (hereinafter also referred to as a lactone ring-containing polymer) is an acrylic resin having a lactone ring in the main chain. Although it does not specifically limit, Preferably it has a lactone ring structure shown by the following general formula (100).

  Formula (100):

In General Formula (100), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain an oxygen atom. .
Here, the organic residue having 1 to 20 carbon atoms is preferably an alkyl group having 1 to 6 carbon atoms, specifically, a methyl group, an ethyl group, an isopropyl group, an n-butyl group, or a t-butyl group. Etc. are preferable.

  The content ratio of the lactone ring structure represented by the general formula (100) in the structure of the lactone ring-containing polymer is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and still more preferably 10 to 60% by mass. %, Particularly preferably 10 to 50% by mass. By setting the content ratio of the lactone ring structure to 5% by mass or more, the heat resistance and surface hardness of the obtained polymer tend to be improved, and by setting the content ratio of the lactone ring structure to 90% by mass or less. The moldability of the obtained polymer tends to be improved.

The content ratio of the lactone ring structure can be calculated from the following formula.
Lactone ring content (% by mass) = B × A × M _R / M _m
(Wherein, B is the mass proportion in the monomer composition used in the copolymerization raw monomer having a structure (hydroxyl group) responsible for the lactonization, M _R lactone ring structure to generate The unit formula weight, M _m is the molecular weight of the raw material monomer having a structure (hydroxyl group) involved in lactone cyclization, and A is the lactone cyclization rate)
In addition, when the cyclization reaction involves a dealcoholization reaction, for example, the lactone cyclization rate can be determined by removing the theoretical weight loss from 150 ° C. before the weight reduction starts to 300 ° C. before the polymer decomposition starts. It can be calculated from the weight loss heating weight loss rate due to the alcohol reaction.

There is no particular limitation on the method for producing the acrylic resin having a lactone ring structure. Preferably, the acrylic resin having a lactone ring structure was obtained after obtaining the polymer (p) having a hydroxyl group and an ester group in the molecular chain by polymerizing the following predetermined monomer: The polymer (p) is obtained by subjecting the polymer (p) to heat treatment at a temperature range of 75 ° C. to 120 ° C. to perform lactone cyclization condensation for introducing a lactone ring structure into the polymer.
In the polymerization step, a polymer having a hydroxyl group and an ester group in the molecular chain is obtained by performing a polymerization reaction of a monomer component containing a monomer represented by the following general formula (101). Formula (101):

(In the formula, R ¹ and R ² each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)

  Examples of the monomer represented by the general formula (101) include methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, 2- ( Hydroxymethyl) normal butyl acrylate, 2- (hydroxymethyl) acrylate t-butyl and the like. Among these, methyl 2- (hydroxymethyl) acrylate and 2- (hydroxymethyl) ethyl acrylate are preferable, and methyl 2- (hydroxymethyl) acrylate is particularly preferable in that the effect of improving heat resistance is high. As for the monomer represented by the general formula (101), only one type may be used, or two or more types may be used in combination.

  The content ratio of the monomer represented by the general formula (101) in the monomer component used in the polymerization step has a lower limit value in a preferable range in terms of heat resistance, solvent resistance, and surface hardness, and was obtained. There is an upper limit of a preferable range from the viewpoint of molding processability of the polymer, and based on these viewpoints, it is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, still more preferably 10 to 60% by mass, and particularly preferably. Is 10-50 mass%.

The monomer component used in the polymerization step may contain a monomer other than the monomer represented by the general formula (101). Such monomers are not particularly limited, but preferred examples include acrylic acid esters, hydroxyl group-containing monomers, unsaturated carboxylic acids, and monomers represented by the following general formula (102). Only one type of monomer other than the monomer represented by formula (101) may be used, or two or more types may be used in combination.
Formula (102):

(Wherein R ⁴ represents a hydrogen atom or a methyl group, X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, a —CO—R ⁵ group, or —CO It represents ^{-O-R 6} group, Ac represents an acetyl group, ^{R 5} and ^{R 6} represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)

  The weight average molecular weight of the lactone ring-containing polymer is preferably 10,000 to 2,000,000, more preferably 20,000 to 1,000,000, and particularly preferably 50,000 to 500,000.

  The lactone ring-containing polymer has a mass reduction rate within a range of 150 to 300 ° C. in dynamic TG measurement, preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.3% or less. It is good. As a method for measuring dynamic TG, the method described in JP-A-2002-138106 can be used.

  Since the lactone ring-containing polymer has a high cyclization condensation reaction rate, there is little dealcoholization reaction in the production process of the molded product, and bubbles and silver stripes (silver streaks) are formed in the molded product after molding due to the alcohol. The disadvantage of entering can be avoided. Furthermore, since the lactone ring structure is sufficiently introduced into the polymer due to a high cyclization condensation reaction rate, the obtained lactone ring-containing polymer has high heat resistance.

  The lactone ring-containing polymer has a coloring degree (YI) of preferably 6 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1 or less when a chloroform solution having a concentration of 15% by mass is used. . If the degree of coloring (YI) is 6 or less, problems such as loss of transparency due to coloring are unlikely to occur, and therefore, it can be preferably used in the present invention.

  The lactone ring-containing polymer has a 5% mass reduction temperature in thermal mass spectrometry (TG) of preferably 330 ° C. or higher, more preferably 350 ° C. or higher, and still more preferably 360 ° C. or higher. The 5% mass reduction temperature in thermal mass spectrometry (TG) is an indicator of thermal stability, and by setting it to 330 ° C. or higher, sufficient thermal stability tends to be exhibited. The thermal mass spectrometry can use the apparatus for measuring the dynamic TG.

  The glass transition temperature (Tg) of the lactone ring-containing polymer is preferably 115 ° C to 180 ° C, more preferably 120 ° C to 170 ° C, and still more preferably 125 ° C to 160 ° C.

(2) Maleic anhydride polymer having a succinic anhydride ring in the main chain
By forming a succinic anhydride structure in the main chain in the molecular chain of the polymer (in the main skeleton of the polymer), the acrylic resin as a copolymer is given high heat resistance, and the glass transition temperature ( Tg) is also preferable because it increases.
The glass transition temperature (Tg) of the maleic anhydride polymer having a succinic anhydride ring in the main chain is preferably 110 ° C to 160 ° C, more preferably 115 ° C to 160 ° C, still more preferably 120 ° C to 160 ° C. is there.
The weight average molecular weight of the maleic anhydride polymer having a succinic anhydride ring in the main chain is preferably in the range of 50,000 to 500,000.

The maleic anhydride unit used for copolymerization with the acrylic resin is not particularly limited, but JP-A-2008-216586, JP-A-2009-052021, JP-A-2009-196151, JP-T-2012-504783. Mention may be made of maleic acid-modified resins described in the respective publications.
In addition, these do not limit this invention.
As a commercially available maleic acid-modified resin, Delpet 980N manufactured by Asahi Kasei Chemicals Corporation, which is a maleic acid-modified MAS resin (methyl methacrylate-acrylonitrile-styrene copolymer), can be preferably used.
In addition, a method for producing an acrylic resin containing a maleic anhydride unit is not particularly limited, and a known method can be used.

  The maleic acid-modified resin is not limited as long as the resulting polymer contains maleic anhydride units, and examples thereof include (anhydrous) maleic acid-modified MS resin, (anhydrous) maleic acid-modified MAS resin (methacrylic acid). Methyl-acrylonitrile-styrene copolymer), (anhydrous) maleic acid modified MBS resin, (anhydrous) maleic acid modified AS resin, (anhydrous) maleic acid modified AA resin, (anhydrous) maleic acid modified ABS resin, ethylene-maleic anhydride Examples thereof include acid copolymers, ethylene-acrylic acid-maleic anhydride copolymers, and maleic anhydride grafted polypropylene.

The maleic anhydride unit has a structure represented by the following general formula (200).
General formula (200):

In the general formula (200), R ²¹ and R ²² each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.
The organic residue is not particularly limited as long as it has 1 to 20 carbon atoms, and examples thereof include a linear or branched alkyl group, a linear or branched alkylene group, an aryl group, and an -OAc group. , -CN group and the like. The organic residue may contain an oxygen atom. Ac represents an acetyl group.
R ²¹ and R ²² preferably have 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.

In the case where R ²¹ and R ²² each represent a hydrogen atom, it is preferable that other copolymer components are further included from the viewpoint of adjusting the intrinsic birefringence. As such a ternary or higher heat-resistant acrylic resin, for example, methyl methacrylate-maleic anhydride-styrene copolymer can be preferably used.

(3) Polymer having glutaric anhydride ring structure in the main chain The polymer having glutaric anhydride ring structure in the main chain is a polymer having a glutaric anhydride unit.

  The polymer having a glutaric anhydride unit preferably has a glutaric anhydride unit represented by the following general formula (300) (hereinafter referred to as a glutaric anhydride unit).

  General formula (300):

In general formula (300), R <^31> , R ^<32 > represents a hydrogen atom or a C1-C20 organic residue each independently. The organic residue may contain an oxygen atom. R ³¹ and R ³² particularly preferably represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.

The polymer having glutaric anhydride units is preferably an acrylic resin containing glutaric anhydride units. The acrylic resin preferably has a glass transition temperature (Tg) of 120 ° C. or higher from the viewpoint of heat resistance.
The glass transition temperature (Tg) of the polymer having a glutaric anhydride ring structure in the main chain is preferably 110 ° C to 160 ° C, more preferably 115 ° C to 160 ° C, and further preferably 120 ° C to 160 ° C.
The weight average molecular weight of the polymer having a glutaric anhydride ring structure in the main chain is preferably in the range of 50,000 to 500,000.

  As content of the glutaric anhydride unit with respect to acrylic resin, 5-50 mass% is preferable, More preferably, it is 10-45 mass%. When the content is 5% by mass or more, more preferably 10% by mass or more, an effect of improving heat resistance can be obtained, and further an effect of improving weather resistance can be obtained.

(4) Acrylic resin having a glutarimide ring structure in the main chain An acrylic resin having a glutarimide ring structure in the main chain (hereinafter also referred to as a glutarimide resin) is optical by having a glutarimide ring structure in the main chain. A desirable balance of properties can be expressed in terms of properties and heat resistance. The acrylic resin having a glutarimide ring structure in the main chain is at least the following general formula (400):

Formula (400):

Wherein R ³⁰¹ , R ³⁰² , and R ³⁰³ are independently hydrogen or an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or an aryl group. It is preferable to contain a glutarimide resin having 20% by mass or more.

As preferred glutarimide units constituting the glutarimide resin used in the present invention, R ³⁰¹ and R ³⁰² are a hydrogen atom or a methyl group, and R ³⁰³ is a methyl group or a cyclohexyl group. The glutarimide unit may be a single type or may include a plurality of types in which R ³⁰¹ , R ³⁰² , and R ³⁰³ are different.

  A preferred second structural unit constituting the glutarimide resin used in the present invention is a unit composed of an acrylate ester or a methacrylate ester. Preferable acrylic acid ester or methacrylic acid ester structural unit includes methyl acrylate, ethyl acrylate, methyl methacrylate, methyl methacrylate and the like. Another preferred imidizable unit includes N-alkyl methacrylamide such as N-methyl methacrylamide and N-ethyl methacrylamide. These second structural units may be of a single type or may include a plurality of types.

  The content of the glutarimide unit represented by the general formula (400) in the glutarimide resin is preferably 20% by mass or more and 95% by mass or less based on the total repeating unit of the glutarimide resin. More preferably, it is 50-90 mass%, More preferably, it is 60-80 mass%. When the content of the glutarimide unit is 20% by mass or more, it is preferable from the viewpoint of ensuring heat resistance and transparency of the obtained film. If it is 95 mass% or less, it is preferable from a viewpoint of the brittleness of a film, transparency, and film formation.

  The glutarimide resin may be further copolymerized with a third structural unit, if necessary. Preferred examples of the third structural unit include styrene monomers such as styrene, substituted styrene and α-methylstyrene, acrylic monomers such as butyl acrylate, and nitrile monomers such as acrylonitrile and methacrylonitrile. , A structural unit obtained by copolymerizing maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide can be used. These may be directly copolymerized with the glutarimide unit and the imidizable unit in the glutarimide resin, and graft copolymerized with the resin having the glutarimide unit and the imidizable unit. It may be polymerized. When the third component is added, the content in the glutarimide resin is preferably 5 mol% or more and 30 mol% or less based on the total repeating units in the glutarimide resin.

  The glutarimide resin is described in US Pat. No. 3,284,425, US Pat. No. 4,246,374, JP-A-2-153904, and the like, and is obtained by using methyl methacrylate as a main raw material as a resin having an imidizable unit. It can be obtained by using a resin and imidizing the resin having an imidizable unit with ammonia or a substituted amine. When obtaining a glutarimide resin, a unit composed of acrylic acid, methacrylic acid, or an anhydride thereof may be introduced into the glutarimide resin as a reaction by-product. The presence of such a structural unit, particularly an acid anhydride, is not preferable because it reduces the total light transmittance and haze of the obtained film of the present invention. The acrylic acid or methacrylic acid content is 0.5 milliequivalent or less per gram of resin, preferably 0.3 milliequivalent or less, more preferably 0.1 milliequivalent or less. In addition, as seen in JP-A No. 02-153904, it is also possible to obtain a glutarimide resin by imidization using a resin mainly composed of N-methylacrylamide and methacrylic acid methyl ester.

The glass transition temperature (Tg) of the glutar resin is preferably 110 ° C. to 160 ° C., more preferably 115 ° C. to 160 ° C., and still more preferably 120 ° C. to 160 ° C.
The weight average molecular weight of the glutar resin is preferably in the range of 50,000 to 500,000.

  The optical film of the present invention may be mixed with other resins in addition to the acrylic resin. The mass ratio of the acrylic resin and the other resin is preferably 70:30 to 100: 0, more preferably 80:20 to 100: 0, and still more preferably 90:10 to 100: 0. Particularly preferred is 98: 2 to 100: 0, and most preferred is 100: 0. It is preferable for the mass ratio of the acrylic resin and the other resin to be in the range of 80:20 to 100: 0 because the moisture permeability is low and the humidity expansion of the polarizer due to water transmitted through the film can be further suppressed.

-Manufacturing method of optical film made of acrylic resin-
Hereinafter, a manufacturing method for forming a thermoplastic resin film mainly composed of an acrylic resin will be described in detail.
In order to form an optical film using an acrylic resin as a main component, for example, a film raw material is pre-blended with a conventionally known mixer such as an omni mixer, and then the obtained mixture is extruded and kneaded. In this case, the mixer used for extrusion kneading is not particularly limited. For example, a conventionally known mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader can be used. .

  Examples of the film forming method include conventionally known film forming methods such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Of these film forming methods, the melt extrusion method is particularly suitable.

  Examples of the melt extrusion method include a T-die method and an inflation method, and the molding temperature at that time may be appropriately adjusted according to the glass transition temperature of the film raw material, and is not particularly limited. For example, it is preferably 150 ° C to 350 ° C, more preferably 200 ° C to 300 ° C.

  When forming a film by the T-die method, a roll-shaped film can be obtained by attaching a T-die to the tip of a known single-screw extruder or twin-screw extruder and winding the film extruded into a film. it can. At this time, it is possible to perform uniaxial stretching by appropriately adjusting the temperature of the take-up roll and adding stretching in the extrusion direction. Further, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

The optical film of the present invention is preferably a stretched film made of an acrylic resin. In the case of a stretched film, either a uniaxially stretched film or a biaxially stretched film may be used. In the case of a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved.
When the acrylic resin is an acrylic resin having a cyclic structure in the main chain, it is possible to suppress an increase in retardation even when stretched by mixing with other thermoplastic resins. A film having isotropic properties can be obtained.
The thickness of the optical film made of acrylic resin is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm. When the thickness is 5 μm or more, the film strength can be improved, and in addition, durability deterioration such as crimping can be suppressed, which is preferable. When the thickness is 80 μm or less, it is possible to ensure appropriate moisture permeability in addition to ensuring transparency of the film.

The optical film of the present invention comprises an acrylic resin,
The tensile modulus (EMD) in the machine direction (MD direction) and the tensile modulus (ETD) in the direction perpendicular to the machine direction (TD direction) satisfy the relationship of formula (1).
Formula (1) EMD / ETD <0.8
More preferably, 0.5 <EMD / ETD <0.8, more preferably 0.6 <EMD / ETD <0.79, and most preferably 0.73 <EMD / ETD <0.78. .

The tensile elastic modulus in the machine direction (MD direction) of the optical film of the present invention is preferably 1.2 × 10 ^{9 to} 4.0 × 10 ⁹ N / m ² (1.2 GPa to 4.0 GPa), and is perpendicular to the machine direction. It is preferable that the tensile elastic modulus in a straight direction (TD direction) is 1.5 × 10 ^{9 to} 5.0 × 10 ⁹ N / m ² . Further, the tensile modulus in the machine direction (MD direction) is preferably 2.0 × 10 ^{9 to} 3.5 × 10 ⁹ N / m ² , and the tensile modulus in the direction perpendicular to the machine direction (TD direction) is 2 More preferably, it is 5 × 10 ^{9 to} 4.4 × 10 ⁹ N / m ² .

  In the optical film of the present invention, the in-plane retardation value Re represented by Re = (nx−ny) × d is preferably 0 nm ≦ Re <20 nm. More preferably, 0 nm ≦ Re ≦ 15 nm, and further preferably 0 nm ≦ Re ≦ 10 nm.

  In the optical film of the present invention, the retardation value Rth in the film thickness direction represented by Rth = ((nx + ny) / 2−nz) × d is preferably | Rth | ≦ 25 nm. More preferably, | Rth | ≦ 20 nm, more preferably | Rth | ≦ 10 nm, and most preferably −10 nm ≦ Rth ≦ 5 nm.

In this specification, Re (λnm) and Rth (λnm) each represent in-plane retardation and retardation in the thickness direction at a wavelength λ (unit: nm). Re (λnm) is measured by making light having a wavelength of λnm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments). In selecting the measurement wavelength λnm, the wavelength selection filter can be exchanged manually, or the measurement value can be converted by a program or the like. When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λnm) is calculated by the following method.
Rth (λnm) is Re (λnm), and the in-plane slow axis (determined by KOBRA 21ADH or WR) is the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light is incident at a wavelength of λ nm in 10 ° steps from the normal direction to 50 ° on one side with respect to the normal direction of the film (with the direction of the rotation axis as the rotation axis), and a total of 6 points are measured. KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.
In the above, there is no description regarding λ, and when only Re and Rth are described, it represents a value measured using light having a wavelength of 590 nm. In addition, in the case of a film having a retardation value of zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, the retardation value at a tilt angle larger than that tilt angle. After changing its sign to negative, KOBRA 21ADH or WR calculates.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (when there is no slow axis, the arbitrary direction in the film plane is the rotation axis), Rth can also be calculated from the following formulas (3) and (4) based on the value, the assumed value of the average refractive index, and the input film thickness value.

Formula (3)

[In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. Further, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction orthogonal to nx in the plane, nz represents the refractive index in the thickness direction orthogonal to nx and ny, and d Represents the film thickness of the film. ]
Formula (4): Rth = ((nx + ny) / 2−nz) × d
In the above measurement, as the assumed value of the average refractive index, the values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. If the average refractive index is not known, it can be measured with an Abbe refractometer. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). By inputting these average refractive index and film thickness, KOBRA 21ADH or WR calculates nx, ny, and nz. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

<Polarizing plate>
The polarizing plate of the present invention has the polarizer and the optical film of the present invention on at least one surface of the polarizer. The polarizing plate of the present invention preferably has the optical film of the present invention on both surfaces of a polarizer.
The polarizing plate of the present invention preferably has the polarizer and the optical film of the present invention as a protective film for the polarizer, and the polarizing plate has a protective film / polarizer / protective film or protective film / polarized light. A child and a protective film / polarizer / functional layer are preferred.
Regarding the polarizing plate protective film which comprises the polarizing plate of this invention, there is no restriction | limiting in particular about the material which can be used for protective films other than the optical film of the said invention. It may be a layer or film made of various polymers (hereinafter sometimes referred to collectively as “film”). For example, cellulose acylate polymer, polycarbonate polymer, polyester such as polyethylene terephthalate and polyethylene naphthalate Polymers, acrylic polymers such as polymethyl methacrylate, styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin), and the like can be used. In addition, polyolefins such as polyethylene and polypropylene, polyolefin polymers such as ethylene / propylene copolymers, cycloolefin polymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers, Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinylidene chloride polymer, vinyl alcohol polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the aforementioned polymer A polymer layer or a film may be produced by selecting one type or two or more types of polymers from a polymer or the like mixed with a polymer as a main component. Further, it may be a layer formed by polymerizing a rod-like liquid crystal having a polymerizable group or a discotic liquid crystal in a predetermined alignment state and fixing it.
In the polarizing plate of the present invention, when another optical film is bonded to the surface of the polarizer opposite to the surface on which the optical film of the present invention is bonded, the other optical film may have a functional layer. it can. In order to improve adhesion with a polarizer or other functional layer, an easy adhesion layer can be provided as the functional layer.

The polarizing plate of the present invention can be produced by a general method. For example, it is a method of laminating a polarizer and the optical film of the present invention.
For the lamination, an adhesive is usually used. The adhesive layer between the polarizer and the polarizing plate protective film on both sides can have a thickness of about 0.01 to 30 μm, preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm. is there. If the thickness of the adhesive layer is within this range, no adhesion or practical problem will be obtained without floating or peeling between the laminated polarizing plate protective film and the polarizer.

As one of the preferable adhesives, an aqueous adhesive, that is, an adhesive component dissolved or dispersed in water can be exemplified, and an adhesive made of an aqueous polyvinyl alcohol resin solution is preferably used.
In an adhesive comprising an aqueous polyvinyl alcohol resin solution, the polyvinyl alcohol resin includes a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as vinyl acetate and this. Examples include vinyl alcohol copolymers obtained by saponifying a copolymer with other polymerizable monomers, and modified polyvinyl alcohol polymers obtained by partially modifying their hydroxyl groups.
To this adhesive, a polyvalent aldehyde, a water-soluble epoxy compound, a melamine compound, a zirconia compound, a zinc compound, a glyoxylate and the like may be added as a crosslinking agent. When an aqueous adhesive is used, the thickness of the adhesive layer obtained therefrom is usually 1 μm or less.

Another preferred adhesive is a curable adhesive composition containing an epoxy compound that is cured by irradiation with active energy rays or heating. Here, the curable epoxy compound has at least two epoxy groups in the molecule. In this case, the adhesive between the polarizer and the protective film is applied to the coating layer of the adhesive composition by irradiating active energy rays or applying heat, and a curable epoxy compound contained in the adhesive. It can carry out by the method of hardening. Curing of the epoxy compound is generally performed by cationic polymerization of the epoxy compound. Further, from the viewpoint of productivity, this curing is preferably performed by irradiation with active energy rays.
When a curable adhesive is used, the thickness of the adhesive layer obtained therefrom is usually about 0.5 to 5 μm.

  When using a curable adhesive, after bonding a film using a bonding roll, drying is performed as necessary, and the curable adhesive is cured by irradiating with active energy rays or heating. . The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable, and specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp A microwave excited mercury lamp, a metal halide lamp, or the like is preferably used.

  From the viewpoint of weather resistance, refractive index, cationic polymerizability, etc., the epoxy compound contained in the curable adhesive composition is preferably one that does not contain an aromatic ring in the molecule. Examples of epoxy compounds that do not contain an aromatic ring in the molecule include hydrogenated epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. Epoxy compounds suitably used for such a curable adhesive composition are described in detail in, for example, Japanese Patent Application Laid-Open No. 2004-245925.

  In addition, when the optical film of the present invention and the polarizer are bonded with an adhesive, the surface of the optical film of the present invention facing the polarizer is treated with a surface treatment (eg, glow) for the purpose of improving the adhesive strength. Discharge treatment, corona discharge treatment, ultraviolet (UV) treatment) or easy adhesion layer formation may be performed. The materials and forming methods of the easy adhesion layer described in JP 2007-127893 A, JP 2007-127893 A, and the like can be used.

  Moreover, when using films other than the optical film of this invention as a protective film, for example in the aspect using a cellulose acylate film (cellulose acylate type polymer layer), the back surface of a cellulose acylate film and a polarizer are bonded together. Can be produced. In an embodiment in which an aqueous adhesive is used for bonding the cellulose acylate film and the polarizer, it is preferable that the bonding surface of the cellulose acylate film is subjected to alkali saponification treatment. Moreover, complete saponification type polyvinyl alcohol aqueous solution can be used for bonding.

  As said polarizer, what was manufactured by the conventionally well-known method can be used, and a polyvinyl-alcohol-type polarizer is preferable. For example, a film made of a hydrophilic polymer such as polyvinyl alcohol or ethylene-modified polyvinyl alcohol having an ethylene unit content of 1 to 4 mol%, a polymerization degree of 2000 to 4000, and a saponification degree of 99.0 to 99.99 mol%, A film stretched by treatment with a dichroic dye such as the above, or a film oriented by treating a plastic film such as vinyl chloride is used.

  Moreover, as a method of obtaining a polarizer film of 10 μm or less by stretching and dyeing in the state of a laminated film in which a polyvinyl alcohol layer is formed on a substrate, Patent No. 5048120, Patent No. 5143918, Patent No. 5048120 No. 4, Patent No. 4691205, Patent No. 4751481 and Patent No. 4751486 can be cited, and known techniques relating to these polarizers can also be preferably used for the polarizing plate of the present invention.

<Functional layer>
The polarizing plate of the present invention preferably has a functional layer on at least one surface of the optical film of the present invention which is a protective film. Examples of the functional layer include a pattern retardation layer for displaying a three-dimensional image, a λ / 4 layer, a hard coat layer, an antireflection layer, an antiglare layer, an antistatic layer, an optically anisotropic layer, and an easy adhesion layer. Each functional layer may be used alone or in combination. In particular, in the embodiment in which the pattern retardation layer or the λ / 4 layer is provided on the optical film of the present invention, the other surface of the optical film of the present invention, or the pattern retardation layer or the λ / 4 layer is provided. An embodiment in which a hard coat layer is provided is preferred. In the aspect in which the hard coat layer is provided on the pattern retardation layer or the λ / 4 layer, the hard coat layer, the layer disposed on the visual recognition side of the pattern retardation layer or the λ / 4 layer, or the hard coat layer. It is preferable that the coat layer has ultraviolet absorbing ability.
When the polarizing plate of the present invention has a structure in which a polarizer is sandwiched between the protective film / polarizer / functional layer, that is, the protective film, the optical film of the present invention and the functional layer, in the liquid crystal display device, the functional layer is In an embodiment in which the functional layer is disposed closer to the liquid crystal cell, the functional layer is preferably a λ / 4 layer, an optically anisotropic layer, a hard coat layer, an antistatic layer, or an easy adhesion layer.

<Pattern retardation layer>
The pattern retardation layer includes a first retardation region and a second retardation region in which at least one of an in-plane slow axis direction and an in-plane retardation is different from each other, and the first and second retardation regions are in-plane The first phase difference region and the second phase difference region have a boundary portion. An example is an optically anisotropic layer in which the first and second retardation regions each have Re of about λ / 4 and the in-plane slow axes are orthogonal to each other. There are various methods for forming such a pattern retardation layer, and it is formed by polymerizing and fixing a rod-like liquid crystal having a polymerizable group in a horizontally aligned state and a discotic liquid crystal in a vertically aligned state. It is preferable to do.
In general, liquid crystal compounds can be classified into a rod type and a disk type from the shape. In addition, there are low and high molecular types, respectively. Polymer generally refers to a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992). Any liquid crystal compound can be used in the patterned optically anisotropic layer used in the present invention, but a rod-like liquid crystal compound or a disk-like liquid crystal compound is preferably used. Two or more kinds of rod-like liquid crystal compounds, two or more kinds of disk-like liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a disk-like liquid crystal compound may be used. It is more preferable to use a rod-like liquid crystal compound or a disk-like liquid crystal compound having a reactive group, since at least one of the reactive groups in one liquid crystal molecule is at least one because a change in temperature and humidity can be reduced. Is more preferable. The liquid crystal compound may be a mixture of two or more types, and in that case, at least one preferably has two or more reactive groups.
As the rod-like liquid crystal compound, for example, those described in JP-A-11-513019 and JP-A-2007-279688 can be preferably used, and examples of the discotic liquid crystal compound include JP-A-2007-108732. Although what is described in gazette and Unexamined-Japanese-Patent No. 2010-244038 can be used preferably, it is not limited to these.

  It is also preferable that the liquid crystal compound has two or more reactive groups having different polymerization conditions. In this case, it is possible to produce a retardation layer containing a polymer having an unreacted reactive group by selecting conditions and polymerizing only a part of plural types of reactive groups. The polymerization conditions used may be the wavelength range of ionizing radiation used for polymerization immobilization, or the difference in polymerization mechanism used, but preferably a radical reaction group and a cationic reaction that can be controlled by the type of initiator used. A combination of groups is good. A combination in which the radical reactive group is an acrylic group and / or a methacryl group and the cationic group is a vinyl ether group, an oxetane group and / or an epoxy group is particularly preferable because the reactivity can be easily controlled.

The optically anisotropic layer can be formed by various methods using an alignment film, and the production method is not particularly limited.
The first aspect uses a plurality of actions that affect the alignment control of the liquid crystal, and then eliminates any action by an external stimulus (such as heat treatment) to make the predetermined alignment control action dominant. It is. For example, by combining the alignment control ability of the alignment film with the alignment control ability of the alignment control agent added to the liquid crystal compound, the liquid crystal is brought into a predetermined alignment state and fixed to form one retardation region. After that, by external stimulus (heat treatment, etc.), one of the actions (for example, the action by the alignment control agent) disappears, and the other orientation control action (the action by the alignment film) becomes dominant, thereby causing another alignment state. Is fixed and the other phase difference region is formed. For example, a predetermined pyridinium compound or imidazolium compound is unevenly distributed on the surface of the hydrophilic polyvinyl alcohol alignment film because the pyridinium group or imidazolium group is hydrophilic. In particular, if the pyridinium group is further substituted with an amino group that is a substituent of an acceptor of a hydrogen atom, intermolecular hydrogen bonds are generated with polyvinyl alcohol, and are unevenly distributed on the surface of the alignment film at a higher density. At the same time, due to the effect of hydrogen bonding, the pyridinium derivative is aligned in the direction orthogonal to the main chain of polyvinyl alcohol, so that the orthogonal alignment of the liquid crystal is promoted with respect to the rubbing direction. Since the pyridinium derivative has a plurality of aromatic rings in the molecule, a strong intermolecular π-π interaction occurs between the liquid crystal, particularly the discotic liquid crystal compound described above, and the orientation of the discotic liquid crystal. Induces orthogonal orientation in the vicinity of the film interface. In particular, when a hydrophobic aromatic ring is connected to a hydrophilic pyridinium group, it also has an effect of inducing vertical alignment due to the hydrophobic effect. However, the effect is that when heated above a certain temperature, the hydrogen bond is broken, the density of the pyridinium compound or the like on the surface of the alignment film is lowered, and the action disappears. As a result, the liquid crystal is aligned by the regulating force of the rubbing alignment film itself, and the liquid crystal is in a parallel alignment state. Details of this method are described in JP 2012-8170 A, the contents of which are incorporated herein by reference.

  In the second aspect, a pattern alignment film is used. In this embodiment, pattern alignment films having different alignment control capabilities are formed, and a liquid crystal compound is disposed thereon to align the liquid crystal. The alignment of the liquid crystal is regulated by the respective alignment control ability of the pattern alignment film, thereby achieving different alignment states. By fixing the respective alignment states, the patterns of the first and second retardation regions are formed according to the alignment film pattern. The pattern alignment film can be formed using a printing method, mask rubbing for the rubbing alignment film, mask exposure for the photo alignment film, or the like. Alternatively, the alignment film can be formed uniformly, and an additive that affects the alignment control ability (for example, the onium salt or the like) can be separately printed in a predetermined pattern to form the pattern alignment film. A method using a printing method is preferable in that large-scale equipment is not required and manufacturing is easy. Details of this method are described in JP 2012-032661 A, the contents of which are incorporated herein by reference.

  Moreover, you may use the 1st and 2nd aspect together. An example is an example in which a photoacid generator is added to the alignment film. In this example, a photoacid generator is added to the alignment film, and pattern exposure exposes a region where the photoacid generator is decomposed to generate an acidic compound and a region where no acid compound is generated. The photoacid generator remains almost undecomposed in the unirradiated portion, and the interaction between the alignment film material, the liquid crystal, and the alignment control agent added as required dominates the alignment state, and the liquid crystal has its slow axis. Is oriented in a direction perpendicular to the rubbing direction. When the alignment film is irradiated with light and an acidic compound is generated, the interaction is no longer dominant, the rubbing direction of the rubbing alignment film dominates the alignment state, and the liquid crystal has its slow axis parallel to the rubbing direction. Parallel orientation. As the photoacid generator used for the alignment film, a water-soluble compound is preferably used. Examples of photoacid generators that can be used include Prog. Polym. Sci. , 23, 1485 (1998). As the photoacid generator, pyridinium salts, iodonium salts and sulfonium salts are particularly preferably used. Details of this method are described in JP 2012-150428 A, the contents of which are incorporated herein by reference.

(Shape of the first area and the second area)
The optical film of the present invention has a first retardation region (hereinafter also simply referred to as a first region) and a second retardation region (hereinafter also simply referred to as a second region) having different birefringence, and the first An optically anisotropic layer (hereinafter also referred to as a pattern phase difference) in which one phase difference region and the second phase difference region are alternately patterned for each line is included. From the viewpoint of use for a 3D stereoscopic image display system, it is preferable that the first region and the second region have a strip shape in which the lengths of the short sides of the first region and the second region are approximately the same.

In the optical film of the present invention, when the slow axis of the first region and the slow axis of the second region are substantially orthogonal, the first region and the second region are passed when 3D video display is performed. This is preferable from the viewpoint of changing the polarization state of light from linearly polarized light to circularly polarized light, or from circularly polarized light to linearly polarized light.
In the optical film of the present invention, the slow axis of the first region and the slow axis of the second region are orthogonal to each other when passing through the first region and the second region when displaying a 3D image. It is more preferable from the viewpoint that the polarization state of the obtained light can be changed from linearly polarized light to circularly polarized light, or from circularly polarized light to linearly polarized light without being elliptically polarized light.

  In the optical film of the present invention, the direction of the long side of the pattern and the direction in which the sound speed of the support is maximized are substantially orthogonal from the viewpoint of reducing the shift between the pattern area and the pixel and suppressing crosstalk. preferable.

(Retardation)
As described above, the pattern retardation layer having a function of converting from linearly polarized light to circularly polarized light or from circularly polarized light to linearly polarized light preferably has a retardation of ¼ of the wavelength. In general, it is called a quarter-wave plate, and Re = 137.5 nm is an ideal value at a visible light wavelength of 550 nm.
Further, the pattern retardation layer for converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light is not limited to having a retardation of ¼ wavelength. For example, a retardation of -1/4 or 3/4 of the wavelength may be used, and the retardation may be ¼ ± n / 2 (n is an integer) of the wavelength when expressed by a general formula.
Patterning in which the slow axis of the first region and the slow axis of the second region are orthogonal to each other may be performed by alternately forming regions having a retardation of -1/4 or 1/4 of the wavelength. At this time, the slow axes of each region are almost orthogonal. Further, the retardation of 1/4 and 3/4 of the wavelength may be patterned, and the slow axes of the mutual regions at this time are substantially parallel. However, the rotation directions of the circularly polarized light in the respective regions are reversed.
Further, in the patterning of the quarter of the wavelength and the retardation of the quarter, the retardation of 1/2 or −1/2 of the wavelength may be formed after the quarter of the wavelength is formed on the entire surface.
When the optical film of the present invention has a retardation of ¼ of the wavelength, the Re (550) value of the first region included in the optical film and the Re of the second region included in the optical film. (550) The value is preferably 30 to 250 nm, more preferably 50 to 230 nm, particularly preferably 100 to 200 nm, more preferably 105 to 180 nm, and more preferably 115 to 160 nm. Is more preferable, and it is more preferable that it is 120-150 nm.

  In addition, from the viewpoint of changing the polarization state of the light that has passed through the first region and the second region when displaying 3D images from linearly polarized light to circularly polarized light, or from circularly polarized light to linearly polarized light, the pattern retardation layer The total Re (550) of the support and the support is preferably 110 to 165 nm, more preferably 110 to 155 nm, and still more preferably 120 to 145 nm. In particular, the entire Re (550) of the pattern retardation layer and the support is in the above range, and the slow axes of the first region and the second region are substantially orthogonal to each other, so that the right-eye image and the left-eye can be accurately obtained. This is preferable from the viewpoint of changing the polarization state of the image for use.

<Λ / 4 layer>
The λ / 4 layer is an aspect of only the first retardation region described in the section of the pattern retardation layer. In other words, this is not an aspect having two regions having different birefringence but each having a uniform birefringence region. A preferable material and a range of retardation are the same as those of the pattern retardation layer.

<Optically anisotropic layer>
The optically anisotropic layer is a layer formed of the above-mentioned various polymers in a predetermined alignment state, or a layer formed by polymerizing a rod-like liquid crystal having a polymerizable group or a discotic liquid crystal in a predetermined alignment state and fixing it. That is. As the rod-like liquid crystal or discotic liquid crystal having a polymerizable group, the same material as that of the pattern retardation layer can be used.

<Hard coat layer>
The hard coat layer preferably has a thickness of 0.1 to 6 μm, more preferably 3 to 6 μm. By having a thin hard coat layer in the above range, an optical film including a hard coat layer that has improved physical properties such as brittleness and curl suppression, reduced weight, and reduced manufacturing costs is obtained. Further, when the base film has a large elastic modulus, the pencil hardness can be remarkably increased by setting the specific elastic modulus to be equal to or greater than the specific elastic modulus range.
The hard coat layer used in the present invention is a layer for imparting hardness and scratch resistance to the film. The said hard-coat layer can be formed by apply | coating a coating composition on the optical film of this invention which is a base film, and making it harden | cure, for example. Moreover, you may laminate | stack another functional layer on a hard-coat layer for the purpose of adding another function. Also, by adding fillers and additives to the hard coat layer, chemical performance such as mechanical, electrical and optical physical performance and water / oil repellency can be imparted to the hard coat layer itself. .
The hard coat layer preferably has a thickness of 0.1 to 6 μm, more preferably 3 to 6 μm. By having a thin hard coat layer in the above range, an optical film including a hard coat layer that has improved physical properties such as brittleness and curl suppression, reduced weight, and reduced manufacturing costs is obtained. Moreover, pencil hardness can be raised notably by making a base film into the TD direction large tensile elasticity modulus, or more than the range of the said specific tensile elasticity modulus.

  The hard coat layer is preferably formed by curing the curable composition. The curable composition is preferably prepared as a liquid coating composition. An example of the said coating composition contains the monomer or oligomer for matrix formation binders, polymers, and an organic solvent. A hard coat layer can be formed by curing the coating composition after coating. For curing, a crosslinking reaction or a polymerization reaction can be used.

(Monomer or oligomer for matrix forming binder)
Examples of matrix forming binder monomers or oligomers that can be used include ionizing radiation curable polyfunctional monomers and polyfunctional oligomers. The polyfunctional monomer or polyfunctional oligomer is preferably a monomer capable of crosslinking reaction or polymerization reaction. The functional group of the ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.

  Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as (meth) acryloyl group, vinyl group, styryl group, and allyl group, and ring-opening polymerizable functional groups such as epoxy compounds. Of these, a (meth) acryloyl group is preferred.

As a specific example of a photopolymerizable polyfunctional monomer having a photopolymerizable functional group,
(Meth) acrylic acid diesters of alkylene glycol such as neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyoxyalkylene glycols such as triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyhydric alcohols such as pentaerythritol di (meth) acrylate;
(Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts such as 2,2-bis {4- (acryloxy-diethoxy) phenyl} propane and 2,2-bis {4- (acryloxy-polypropoxy) phenyl} propane And the like.

  Furthermore, urethane (meth) acrylates, polyester (meth) acrylates, isocyanuric acid acrylates, and epoxy (meth) acrylates are also preferably used as the photopolymerizable polyfunctional monomer.

Among the above, esters of polyhydric alcohol and (meth) acrylic acid are preferable, and polyfunctional monomers having three or more (meth) acryloyl groups in one molecule are more preferable.
Specifically, (di) pentaerythritol tri (meth) acrylate, (di) pentaerythritol tetra (meth) acrylate, (di) pentaerythritol penta (meth) acrylate, (di) pentaerythritol hexa (meth) acrylate, tri Pentaerythritol triacrylate, tripentaerythritol hexatriacrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO-modified tri (meth) acrylate phosphate, 1,2,4-cyclohexanetetra (meth) acrylate, Printer glycerol triacrylate, 1,2,3-cyclohexane tetramethacrylate, polyester polyacrylate and caprolactone-modified tris (acryloyloxyethyl) isocyanurate, and the like.
In the present specification, “(meth) acrylate”, “(meth) acrylic acid”, and “(meth) acryloyl” represent “acrylate or methacrylate”, “acrylic acid or methacrylic acid”, and “acryloyl or methacryloyl”, respectively. .

Furthermore, resins having three or more (meth) acryloyl groups, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins And oligomers or prepolymers such as polyfunctional compounds such as polyhydric alcohols.
As specific compounds of polyfunctional acrylate compounds having three or more (meth) acryloyl groups, JP-A-2007-256844 [0096] and the like can be referred to.

As urethane acrylates, for example, alcohols, polyols, and / or hydroxyl group-containing compounds such as hydroxyl group-containing acrylates are reacted with isocyanates, and if necessary, polyurethane compounds obtained by these reactions (meth) Mention may be made of urethane acrylate compounds obtained by esterification with acrylic acid.
As specific examples of specific compounds, reference can be made to the description of [0017] in JP-A-2007-256844.

  Use of isocyanuric acid acrylates is preferable because curling can be further reduced. Examples thereof include isocyanuric acid diacrylates and isocyanuric acid triacrylates, and examples of specific compounds can be referred to JP-A-2007-256844 [0018] to [0021].

  In the hard coat layer, an epoxy compound can be further used to reduce shrinkage due to curing. As monomers having an epoxy group for constituting this, monomers having two or more epoxy groups in one molecule are used, and examples thereof include JP-A Nos. 2004-264563, 2004-264564, and Examples thereof include epoxy monomers described in 2005-37737, 2005-37738, 2005-140862, 2005-140862, 2005-140863, 2002-322430 and the like. It is also preferable to use a compound having both epoxy and acrylic functional groups such as glycidyl (meth) acrylate.

(Polymer compound)
The hard coat layer may contain a polymer compound. The explanation and preferred specific examples of the polymer compound are the same as those described in JP 2012-215812 A, and the contents described in this gazette are incorporated in the present specification.

(Curable composition)
Examples and preferred specific examples of the curable composition that can be used for forming the hard coat layer are the same as those described in JP 2012-215812 A, and the contents described in this gazette are described in this specification. Embedded in.

(Properties of hard coat layer)
The hard coat layer is preferably excellent in scratch resistance. Specifically, it is preferable to achieve 3H or higher when a pencil hardness test that is an index of scratch resistance is performed.

  The polarizing plate of the present invention may have other layers in addition to the optical film of the present invention and the hard coat layer in order to exhibit a function suitable for each application. For example, in addition to the antiglare layer and the clear hard coat layer, an antireflection layer, an antistatic layer, an antifouling layer, and the like may be included.

In particular, since image display screens having various types of touch panels that have become popular in recent years are required to have fingerprint resistance and antifouling properties, an antifingerprint layer or antifouling layer is provided on the optical film of the present invention. It is also useful to form.
Regarding the anti-fingerprint layer and the antifouling layer, for example, Japanese Patent No. 4517590, Japanese Patent No. 4638954, International Publication WO2010 / 090116, and International Publication WO2011 / 105594 can be referred to.

  The image display device is not limited, and may be a liquid crystal display device including a liquid crystal cell, an organic EL image display device including an organic EL layer, or a plasma image display device. A cellulose acylate polymer layer, a polyester polymer layer, an acrylic polymer layer, a cycloolefin polymer layer, and a layer made of a composition containing a liquid crystal compound have good bonding properties with a polarizer, and a polarizing plate. It is suitable for use in a liquid crystal display device as an essential member.

  At the time of producing the polarizing plate, when the optical film of the present invention has an in-plane slow axis, it is preferably bonded so that the in-plane slow axis and the transmission axis of the polarizer are parallel or orthogonal.

[Liquid Crystal Display]
The liquid crystal display device of the present invention has at least one polarizing plate of the present invention.
An example of the arrangement method of the optical film of the present invention in the polarizing plate is that the optical film of the present invention is disposed outside the polarizer without having a functional layer such as a hard coat layer (that is, the polarizer of the polarizing plate). It is a surface protective film of a polarizing plate arranged so as to be farther from the liquid crystal cell. Another example of the arrangement method of the optical film of the present invention is that the optical film of the present invention of the polarizing plate on the display surface side is disposed outside the polarizer in a state having a functional layer such as a hard coat layer (that is, the polarizing plate). This is a surface protective film of a polarizing plate disposed farther from the liquid crystal cell than the polarizer. In the liquid crystal display device of the present invention, it is also preferable that the polarizing plate is arranged so that the optical film of the present invention is closer to the liquid crystal cell than the other protective film.
As for other configurations, any configuration of a known liquid crystal display device can be adopted. There is no particular limitation on the mode, and TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric).
Liquid Crystal), AFLC (Anti-ferroelectric)
Liquid crystal display devices such as Liquid Crystal (LCD), Optical Compensatory Bend (OCB), Super Twisted Nematic (STN), Vertically Aligned (VA), and Hybrid Aligned Display (HAN).

As the liquid crystal display device of the present invention, a transmissive liquid crystal display device is preferable, and the transmissive liquid crystal display device is usually composed of a backlight, a liquid crystal cell, and two polarizing plates whose transmission axes are orthogonal, The two polarizing plates are bonded to the viewing side and the backlight side of the liquid crystal cell via an adhesive layer.
The liquid crystal cell includes a liquid crystal layer and two glass substrates provided on both sides of the liquid crystal layer.
As the glass substrate for the liquid crystal display device, silicate glass is used, preferably silica glass or borosilicate glass is used, and most preferably non-alkali borosilicate glass is used. If an alkali component is contained in a glass substrate for a liquid crystal display device, the alkali component is eluted and the TFT may be damaged. Here, the alkali-free borosilicate glass is a glass that does not substantially contain an alkali component, and specifically, a glass having an alkali component of 1000 ppm or less. The content of the alkali component in the present invention is preferably 500 ppm or less, more preferably 300 ppm or less of the alkali component.

  The glass substrate for a liquid crystal display device is a plate-like body having a substantially rectangular shape in plan view, and preferably has a plate thickness of 0.01 mm to 1.1 mm. If it is 0.01 mm or more, it is difficult to be affected by light interference or internal distortion due to deformation of the glass substrate for display to be evaluated, and if it is 1.1 mm or less, the luminance at the time of evaluation is difficult to decrease. A more preferable plate thickness is 0.1 mm to 0.7 mm, and a further preferable plate thickness is 0.1 mm to 0.5 mm.

The method of bonding the polarizing plate of the present invention to the liquid crystal display device is not particularly limited, and a polarizing plate having the size of the display surface of the liquid crystal display device may be prepared and bonded to both surfaces of the liquid crystal cell. .
As a method for bonding the polarizing plate of the present invention to a liquid crystal display device, a roll-to-panel manufacturing method can also be used, which is preferable for improving productivity and yield. The roll-to-panel manufacturing method is disclosed in JP2011-48381, JP2009-175653, JP4628488, JP47229647, WO2012 / 014602, WO2012 / 014571 and the like. Although described, it is not limited to this.

Moreover, the method of laminating the polarizing plate of the present invention to the liquid crystal display device uses a roll around which the strip-shaped sheet-like product of the first polarizing plate having a width corresponding to the short side of the display surface of the liquid crystal display device is wound. A first cutting and bonding step of cutting the first polarizing plate to a length corresponding to the long side of the display surface of the liquid crystal display device, and then bonding the first polarizing plate to one display surface of the liquid crystal cell of the liquid crystal display device; Using a roll around which a strip-like sheet-like product of a second polarizing plate having a width corresponding to the long side of the display surface of the device is wound, the length corresponding to the short side of the display surface of the liquid crystal display device is set. After the two polarizing plates are cut, a bonding method including a second cutting and bonding step of bonding to the other surface of the liquid crystal cell of the liquid crystal display device may be used.
According to the above method, by using a polarizing plate roll having a width corresponding to the short side of the display surface of the liquid crystal display device and a polarizing plate roll having a width corresponding to the long side, Polarizers corresponding to the short side and the long side of the display surface of the liquid crystal display device can be obtained only by cutting at regular intervals. For this reason, the former is cut to a length corresponding to the long side, the latter is cut to a length corresponding to the short side, and bonded to both surfaces of the liquid crystal cell of the liquid crystal display device. Using two rolls having the same anisotropy, the upper and lower polarizing plates can be bonded to the liquid crystal cell so that the optical anisotropy such as the absorption axis is orthogonal.

  Further, in the bonding by the above method, the strip-shaped sheet product is pulled out from the supply device of the liquid crystal cell that supplies the liquid crystal cell and the roll on which the strip-shaped sheet-shaped product of the first polarizing plate is wound up to a predetermined length. The first polarizing plate supplied from the first polarizing plate supply device is attached to one surface of the supply device of the first polarizing plate supplied after cutting and the liquid crystal cell supplied from the supply device of the liquid crystal cell. A first sheet bonding device to be combined, a conveyance supply device for conveying and supplying the liquid crystal cell after the first polarizing plate is bonded, and a belt-shaped sheet shape from a roll on which the belt-shaped sheet-shaped product of the second polarizing plate is wound A second polarizing plate supply device that is supplied after the product is pulled out and cut to a predetermined length, and supplied from the second polarizing plate supply device to the other surface of the liquid crystal cell supplied from the transport supply device Pasted the second polarizing plate A first laminating device, and the first polarizing plate supply device and the second polarizing plate supply device correspond to the long side and the short side of the liquid crystal cell, and one of the supply devices is short. A polarizing plate having a width corresponding to the side is cut by a length corresponding to the long side, and the other supply device is configured to cut a polarizing plate having a width corresponding to the long side by a length corresponding to the short side. It is preferable to use a bonding system characterized by being.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

[Preparation of optical film 1]
[Acrylic resin having a lactone ring structure represented by the following general formula (1) {mass ratio of copolymerization monomer = methyl methacrylate / 2- (hydroxymethyl) methyl acrylate = 8/2, lactone cyclization rate of about 100 %, Lactone ring structure content 19.4 mass%, weight average molecular weight 133000, melt flow rate 6.5 g / 10 min (240 ° C., 10 kgf), Tg 131 ° C.} 90 parts by mass, acrylonitrile-styrene (AS) resin {Toyo ASAS20, manufactured by Toyo Styrene Co., Ltd.} A mixture of 10 parts by mass; Tg127 ° C] pellets was supplied to a twin screw extruder and melt extruded into a sheet at about 280 ° C to form a lactone ring structure having a thickness of 40 µm. An acrylic resin sheet (optical film 1) was obtained.

In the general formula (1), R ¹ is a hydrogen atom, and R ² and R ³ are methyl groups.

[Preparation of optical films 2 to 4]
Except for the thickness, an unstretched acrylic resin sheet was produced under the same conditions as those of the film 1, and the unstretched sheet was stretched in the TD direction to produce optical films 2 to 4 shown in Table 1 below. At this time, the film of the characteristic of Table 1 was obtained by adjusting suitably the raw fabric thickness and draw ratio of an unstretched sheet.
In addition, the tensile elasticity modulus of TD direction can be made high by making the draw ratio of TD direction high.

[Preparation of optical film 5]
An imidized resin was obtained by the method described in JP 2011-138119 A [0173] to [0176]. The imidized resin is an acrylic resin having a glutarimide ring structure in the main chain and not having an aromatic vinyl structure.

100 parts by mass of the imidized resin obtained and 0.10 parts by mass of the following triazine compound A were pelletized using a single screw extruder. Using the pellets, an unstretched film was stretched in the machine direction (MD direction) and the transverse direction (TD direction), and the optical film 5 was produced in the same manner as the optical film 1 under other conditions. The thickness of the obtained optical film 5 was 40 μm.
Triazine compound A

  Me represents a methyl group, and Hx represents a hexyl group.

[Preparation of optical film 6]
In Table 1 below, an unstretched acrylic resin sheet is produced under the same conditions as the optical film 5 except for the thickness, and the unstretched sheet is stretched in the TD direction while appropriately adjusting the thickness of the original fabric and the stretch ratio. The described optical film 6 was produced.

[Preparation of optical film 7]
PMMA (polymethyl methacrylate) resin (Delpet 80N manufactured by Asahi Kasei Chemicals Corporation) is dried with a 90 ° C. vacuum dryer to a moisture content of 0.03% or less, and then PMMA (polymethyl methacrylate) resin. In 100 parts by mass, 1.0 part by mass of UV absorber (ADEKA STAB LA-31 manufactured by ADEKA Corporation), 0.3 part by mass of stabilizer (Irganox 1010 (manufactured by BASF)) in a biaxial kneader PMMA resin pellets were prepared by mixing at 230 ° C.

  The PMMA resin pellet produced above was melt-extruded from a coat hanger type T die using a twin-screw extruder to prepare an unstretched film. This unstretched film was stretched in the longitudinal direction and the transverse direction to produce an optical film 7. The thickness of the obtained film was 40 μm.

[Preparation of optical films 8 to 10]
Except for the thickness, an unstretched acrylic resin sheet is produced under the same conditions as the optical film 7, and the unstretched sheet is stretched in the TD direction while appropriately adjusting the thickness of the raw fabric and the stretch ratio. The described optical films 8 to 10 were produced. At this time, the film of the characteristic of Table 1 was obtained by adjusting suitably the raw fabric thickness and draw ratio of an unstretched sheet.

<Preparation of optical films 11-12>

[Preparation of coating composition HCL-1 for forming a hard coat layer]
8 parts by mass of pentaerythritol triacrylate, 0.5 parts by mass of Irgacure 127 (manufactured by BASF), and 4 parts by mass of a bifunctional acrylic compound represented by the following formula C-3 are mixed to give a hard coat layer-forming coating (HCL- 1) was prepared.

[Production of hard coat layer]
On the optical film 1 produced above, a hard coat layer forming coating solution (HCL-1) is applied by a die coating method, dried at 80 ° C. for 5 minutes, and further subjected to “air cooling of 240 W / cm under nitrogen purge. Using a “metal halide lamp” (manufactured by Eye Graphics Co., Ltd.), an ultraviolet ray having an irradiation amount of 300 mJ / cm ² was irradiated to cure the coating layer to form a hard coat layer having a dry film thickness of 5 μm.
In this way, an optical film 11 with a hard coat layer was produced.
In the same manner, an optical film 12 having a hard coat layer on the optical film 3 was produced.

  Here, the film thickness [μm], tensile elastic modulus [GPa], humidity dimensional change rate [%], Re and Rth [nm] were measured as follows.

[Measurement of film thickness]
A sample of 5 cm square was prepared and left in an environment of 25 ° C. and 60% relative humidity for 48 hours, and then the average value obtained by measuring the film thickness at 6 points in the plane with a micrometer was used as the film thickness.

[Tensile modulus]
The elastic modulus of the optical film was measured according to the method described in JIS K7127.
Let the winding direction of a film roll be a longitudinal direction (MD direction) and the width direction (TD direction) orthogonal to a longitudinal direction. A film sample having a length of 15 cm and a width of 1 cm in the measurement direction was cut out with the longitudinal direction or the width direction as the measurement direction. The sample was placed on a strograph V10-C made by Toyo Seiki so that the chuck interval in the longitudinal direction was 10 cm, and a load was applied to widen the chuck interval at a stretching speed of 10 mm / min, and the force at that time was measured. did. The tensile elastic modulus was calculated from the thickness, force, and elongation of the film previously measured with a micrometer.

[Humidity change rate of optical film]
The humidity dimensional change rate of the optical film was measured by the following method.
Let the winding direction of a film roll be a longitudinal direction (MD direction), and let the direction orthogonal to a longitudinal direction be a transversal direction (TD direction). Using the width direction (TD direction) as a measurement direction, a film sample having a length of 12 cm in the measurement direction and a width of 3 cm was cut out. Pin holes were formed in the sample at intervals of 10 cm along the measurement direction, and after adjusting the humidity for 24 hours at 25 ° C. and a relative humidity of 60%, the interval (length) of the pin holes was measured with a pin gauge. Next, after adjusting the humidity at 25 ° C. and 10% relative humidity for 24 hours, the interval between the pin holes was measured with a pin gauge. Next, the sample was conditioned at 25 ° C. and 80% relative humidity for 24 hours, and the distance between the pin holes was measured with a pin gauge. Using these measured values, the humidity dimensional change rate in the TD direction was calculated by the following equation.
(Formula) Humidity dimensional change rate in TD direction (%) = [{(length at 25 ° C., relative humidity 80%) − (length at 25 ° C., relative humidity 10%)} / (25 ° C., relative humidity 60 % Length)] × 100

[Measurement of Re and Rth]
Re and Rth of the optical film were measured by the following methods.
Each film is conditioned for 24 hours at 25 ° C. and 60% relative humidity, and is then applied to the film surface at 25 ° C. and 60% relative humidity using an automatic birefringence meter (KOBRA-21ADH: manufactured by Oji Scientific Instruments). By measuring the phase difference at a wavelength of 590 nm from the direction tilted in increments of 10 ° from + 50 ° to −50 ° from the normal direction of the film with the vertical direction and the slow axis as the rotation axis, the in-plane retardation value (Re) and The retardation value (Rth) in the film thickness direction was calculated.

<Acetyl cellulose film>
As an acetyl cellulose film, Fuji Film Tack Film TD60 (film thickness 60 μm) was used.

<Polyester film>
[Synthesis of raw material polyester]
(Raw material polyester 1)
As shown below, terephthalic acid and ethylene glycol are directly reacted to distill off water, esterify, and then use a direct esterification method in which polycondensation is performed under reduced pressure, and a polyester (Sb catalyst) by a continuous polymerization apparatus. System PET) was obtained.

(1) Esterification reaction In a first esterification reactor, 4.7 tons of high-purity terephthalic acid and 1.8 tons of ethylene glycol are mixed over 90 minutes to form a slurry, and continuously at a flow rate of 3800 kg / h. It supplied to the 1st esterification reaction tank. Further, an ethylene glycol solution of antimony trioxide was continuously supplied, and the reaction was carried out at a reaction vessel temperature of 250 ° C. with stirring and an average residence time of about 4.3 hours. At this time, antimony trioxide was continuously added so that the amount of Sb added was 150 ppm in terms of element.

  This reaction product was transferred to a second esterification reaction vessel, and reacted with stirring at a temperature in the reaction vessel of 250 ° C. and an average residence time of 1.2 hours. To the second esterification reaction tank, an ethylene glycol solution of magnesium acetate and an ethylene glycol solution of trimethyl phosphate are continuously supplied so that the added amount of Mg and the added amount of P are 65 ppm and 35 ppm in terms of element, respectively. did.

(2) the polycondensation reaction above-obtained esterification reaction product supplied to the first polycondensation reaction vessel continuously stirring, the reaction temperature 270 ° C., the reaction vessel pressure 20 torr (2.67 × 10 ^{- 3} MPa) and polycondensation with an average residence time of about 1.8 hours.

Further, the mixture was transferred to the second double condensation reaction tank, and while stirring in this reaction tank, the reaction tank temperature was 276 ° C., the reaction tank pressure was 5 torr (6.67 × 10 ⁻⁴ MPa), and the residence time was about 1.2 hours. The reaction (polycondensation) was performed under the conditions.

Subsequently, it was further transferred to the third triple condensation reaction tank. In this reaction tank, the reaction tank temperature was 278 ° C., the reaction tank internal pressure was 1.5 torr (2.0 × 10 ⁻⁴ MPa), and the residence time was 1.5 hours. The reaction product (polyethylene terephthalate (PET)) was obtained by reaction (polycondensation) under the following conditions.

  Next, the obtained reaction product was discharged into cold water in a strand form and immediately cut to prepare polyester pellets (cross section: major axis: about 4 mm, minor axis: about 2 mm, length: about 3 mm).

  The obtained polymer had IV = 0.63 (hereinafter abbreviated as PET1).

<Manufacture of polyester film>
-Film forming process-
The raw material polyester (PET) was dried to a water content of 20 ppm or less, and then charged into the hopper 1 of a single-screw kneading extruder 1 having a diameter of 50 mm. The raw material polyester 1 was melted at 300 ° C. and extruded from a die through a gear pump and a filter (pore diameter: 20 μm) under the following extrusion conditions.
The molten resin was extruded from the die under the conditions that the pressure fluctuation was 1% and the temperature distribution of the molten resin was 2%. Specifically, the back pressure was increased by 1% with respect to the average pressure in the barrel of the extruder, and the piping temperature of the extruder was heated at a temperature 2% higher than the average temperature in the barrel of the extruder.
The molten resin extruded from the die was extruded onto a cooling cast drum set at a temperature of 25 ° C., and was brought into close contact with the cooling cast drum using an electrostatic application method. It peeled using the peeling roll arrange | positioned facing the cooling cast drum, and obtained the unstretched polyester film.

  The obtained unstretched polyester film had an intrinsic viscosity IV = 0.62.

  In IV, an unstretched polyester film is dissolved in a 1,1,2,2-tetrachloroethane / phenol (= 2/3 [mass ratio]) mixed solvent, and from the solution viscosity at 25 ° C. in the mixed solvent. Asked.

-Transverse stretching process-
The unstretched polyester film was guided to a tenter (lateral stretching machine), and was stretched laterally by the following method and conditions while holding the end of the film with a clip.

(Preheating part)
The preheating temperature was 90 ° C., and the mixture was heated to a temperature at which stretching was possible.

(Extension part)
The preheated unstretched polyester film was horizontally stretched in the width direction under the following conditions.
<Condition>
-Transverse stretching temperature: 90 ° C
・ Horizontal stretch ratio: 4.3 times

(Heat fixing part)
Next, a heat setting treatment was performed while controlling the film surface temperature of the polyester film within the following range.
<Condition>
・ Heat setting temperature: 180 ℃
・ Heat setting time: 15 seconds

(Heat relaxation part)
The polyester film after heat setting was heated to the following temperature to relax the film.
-Thermal relaxation temperature: 170 ° C
-Thermal relaxation rate: TD direction (film width direction) 2%

(Cooling section)
Next, the polyester film after heat relaxation was cooled at a cooling temperature of 50 ° C.

(Recovery of film)
After cooling, both ends of the polyester film were trimmed by 20 cm. Then, after extruding (knurling) at a width of 10 mm at both ends, it was wound up with a tension of 18 kg / m.
As described above, a polyester film having a thickness of 65 μm was produced.

<Production of cycloolefin polymer film (COP film)>
750 mmol (70.5 g) of bicyclo [2.2.1] hept-2-ene as a monomer, tricyclo [5.2.1.0 ^2,6 ] dec-8-ene having an endo content of 95% 475 mmol (63.6 g), 5-triethoxysilyl-bicyclo [2.2.1] hept-2-ene 25 mmol (6.4 g) as a solvent, 562 g of cyclohexane, 141 g of methylene chloride, styrene as a molecular weight regulator 15 0.0 mmol was charged to a 2,000 mL reaction vessel under nitrogen. Pre-reacted Ni (SbF ₆ ) ₂ precipitated by reacting Ni octanoate in hexane solution with antimony hexafluoride at a molar ratio of 1: 1 at −10 ° C., and diluting with toluene solution. Then, 0.25 mmol, 2.50 mmol of triethylaluminum, and 0.75 mmol of boron trifluoride ethyl etherate were charged as the Ni atom, and the polymerization was carried out. Polymerization was performed at 25 ° C. for 3 hours, and the polymerization was stopped with methanol. Conversion of the monomer to the copolymer was 80%.

  660 mL of water and 47.5 mmol of lactic acid were added to the copolymer solution, and the mixture was stirred and mixed to react with the catalyst component, and the copolymer solution and water were separated from each other. The copolymer solution from which the aqueous phase containing the reaction product of the catalyst component was removed was placed in 3 L of isopropyl alcohol to solidify the copolymer, thereby removing unreacted monomers and remaining catalyst residues. The coagulated copolymer was dried to obtain copolymer A.

From the gas chromatographic analysis of the unreacted monomers in the copolymer solution, the proportion of structural units derived from tricyclo [5.2.1.0 ^2,6 ] dec-8-ene in copolymer A is It was 35 mol%. The proportion of structural units derived from 5-triethoxysilyl-bicyclo [2.2.1] hept-2-ene was 2.0 mol%.
The number average molecular weight (Mn) in terms of polystyrene of the copolymer A was 142,000, the weight average molecular weight (Mw) was 284,000, and Mw / Mn was 2.0. The glass transition temperature of copolymer A was 390 ° C. Copolymer A was dissolved in cyclohexane at 25 ° C. but not in n-heptane.

  10 g of copolymer A was dissolved in a mixed solvent of 45 mL of cyclohexane as a good solvent and 5 mL of n-heptane as a poor solvent, and pentaerythrityl-tetrakis [3- (3,5-di-) as an antioxidant. t-butyl-4-hydroxyphenyl) propionate] and tris (2,4-di-t-butylphenyl) phosphite are each 0.6 parts by mass with respect to 100 parts by mass of copolymer A as a crosslinking agent. 0.05 part by mass of tributyl phosphate was added to 100 parts by mass of copolymer A. This polymer solution is filtered through a membrane filter having a pore size of 10 μm to remove foreign matters, cast at 25 ° C., gradually raised the temperature of the atmosphere to 50 ° C., the mixed solvent is evaporated, and the residual solvent in the film is 2 %, The film was exposed to steam at 150 ° C. for 3 hours to give a crosslinked product. Then, the surface water | moisture content was removed by vacuum-drying for 30 minutes at 100 degreeC, and the unstretched COP film was produced.

  The unstretched COP film was heated to 130 ° C. in a tenter, stretched 1.15 times in the longitudinal direction in the film in-plane direction at a stretching speed of 300% / min, and then stretched 1.4 times in the transverse direction. While maintaining this state for about 1 minute in an atmosphere of 90 ° C., the mixture was further cooled at room temperature and taken out from the tenter to obtain a COP film. The thickness was 50 μm.

(Production of polarizer)
200 kg of 18 ° C. water was placed in a 500 L tank, and while stirring, 42 kg of polyvinyl alcohol resin having a weight average molecular weight of 165000 and a saponification degree of 99.8 mol% was added and stirred for 15 minutes. The obtained slurry was dehydrated to obtain a polyvinyl alcohol resin wet cake having a water content of 40%.

  70 kg (42 kg of resin content) of the obtained polyvinyl alcohol-based resin wet cake was placed in a dissolution tank, 4.2 kg of glycerin and 10 kg of water were added as plasticizers, and steam was blown from the bottom of the tank. When the internal resin temperature reaches 50 ° C., stirring (rotation speed: 5 rpm) is performed. When the internal resin temperature reaches 100 ° C., the system is pressurized and heated to 150 ° C., and then steam is blown into the system. Stopped (a total of 75 kg of steam was blown in). After stirring for 30 minutes (rotation speed: 20 rpm) and uniformly dissolving, a polyvinyl alcohol resin aqueous solution having a polyvinyl alcohol resin concentration of 23% with respect to water was obtained by adjusting the concentration.

  Next, an aqueous polyvinyl alcohol resin solution (liquid temperature: 147 ° C.) was supplied from a supply gear pump to a biaxial extruder, defoamed, and then discharged by a discharge gear pump. The discharged polyvinyl alcohol-based resin aqueous solution was cast from a T-type slit die (straight manifold hole die) onto a cast drum to form a film. The conditions for casting film formation are as follows.

Cast drum diameter (R1): 3200 mm,
Cast drum width 4.3m,
Cast drum rotation speed: 8m / min,
Cast drum surface temperature: 90 ° C
Resin temperature at T-type slit die outlet: 95 ° C
Drying was performed while alternately passing a plurality of drying rolls on the front and back surfaces of the obtained film under the following conditions.

Drying roll diameter (R2): 320 mm,
Drying roll width: 4.3m,
Number of drying rolls (n): 10
Drying roll rotation speed: 8 m / min,
Drying roll surface speed: 50 ° C

  The polyvinyl alcohol film (length 4000 m, width 4 m, thickness 60 μm) produced above was immersed in warm water at 40 ° C. for 2 minutes, swelled, and then stretched 1.30 times. The obtained film was prepared by using boric acid (manufactured by Societa Chirda Ladderello sp.) 28.6 g / L, iodine (manufactured by Junsei Kagaku) 0.25 g / L, potassium iodide (manufactured by Junsei Kagaku) 1. It was immersed in an aqueous solution containing 0 g / L at 30 ° C. for 2 minutes and dyed with iodine and iodide. The film obtained by the dyeing treatment was treated for 5 minutes in a 50 ° C. aqueous solution containing 30.0 g / L of boric acid while being uniaxially stretched 5.0 times. The obtained film was dried at 70 ° C. for 9 minutes.

[Adhesive for polarizing plate used in bonding method A]
An adhesive for polarizing plate was prepared by blending 100 parts by mass of 2-hydroxyethyl acrylate, 10 parts by mass of tolylene diisocyanate and 3 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by BASF).

(Production of polarizing plate using bonding method A)
Elongated optical films 1 to 12, a COP film, and a polyester film were prepared by the above-described method, and the surface thereof was subjected to corona treatment. Next, the adhesive for polarizing plate is applied on each film using a micro gravure coater (gravure roll: # 300, rotational speed 140% / line speed) so as to have a thickness of 5 μm. An attached optical film was obtained. Subsequently, the optical film with an adhesive was bonded to both surfaces of the polarizer by roll-to-roll using a roll machine. At this time, combinations of optical films described in Tables 2, 4, and 5 were selected as an air side (viewing side) protective film and a cell side protective film, and polarizing plate samples were prepared. Ultraviolet rays were irradiated from the bonded optical film side (both sides) to obtain a polarizing plate having a transparent protective film on both sides of the polarizer. The line speed was 20 m / min, and the cumulative amount of ultraviolet light was 300 mJ / cm ² .
As a result, a polarizing plate sample having a film length of 500 m, an absorption axis in the longitudinal direction, a slow axis in the direction perpendicular to the longitudinal direction, and both surfaces protected by the optical film was obtained.
Polarizing plate samples 1 to 15 and 25 to 36 were produced by this bonding method.

(Production of polarizing plate using bonding method B)
Corona treatment was performed on the surfaces of the long optical films 1 to 3 and 5 to 10 produced by the above method. Next, the surface of the long tack film TD60 was subjected to saponification treatment. In order to sandwich the polarizer between the corona-treated optical film and the saponified tack film, using a polyvinyl alcohol-based adhesive, the roll film is bonded to both sides of the polarizer by roll-to-roll, and the film is bonded at 70 ° C. Dried for more than a minute. At this time, a combination of optical films shown in Table 3 was selected as an air side (viewing side) protective film and a cell side protective film to prepare a polarizing plate sample. As a result, a polarizing plate sample having a film length of 500 m, an absorption axis in the longitudinal direction, a slow axis in the direction perpendicular to the longitudinal direction, and both surfaces protected by the optical film was obtained.
Polarizing plate samples 16 to 24 were prepared by this bonding method.

(Lamination film lamination)
A laminate film (film thickness: 38 μm) mainly composed of polyethylene terephthalate with a pressure-sensitive adhesive was attached to each of the produced polarizing plate samples on the air-side protective film side by roll-to-roll using a roll machine.

(Formation of adhesive layer)
(Preparation of adhesive)
In a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirring device, 100 parts by mass of isooctyl acrylate, 0.085 parts by mass of 6-hydroxyhexyl acrylate, and 2,2′-azobisisobutyronitrile 0 A solution was prepared by adding 4 parts by weight with ethyl acetate. Next, the solution was stirred while blowing nitrogen gas and reacted at 60 ° C. for 4 hours to obtain a solution containing an acrylic polymer PA having a weight average molecular weight of 1.75 million. Furthermore, the acrylic polymer solution which added ethyl acetate to the solution containing this acrylic polymer PA and adjusted solid content concentration to 30 mass% was obtained.

  2.5 parts by mass of a crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name “Coronate L”) mainly composed of a compound having an isocyanate group with respect to 100 parts by mass of the solid content of the acrylic polymer solution; As a silane coupling agent, 0.02 part by mass of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”) is blended in this order to prepare an adhesive solution. did.

(Formation of adhesive layer)
The pressure-sensitive adhesive solution was uniformly coated on the cell side protective film side of the prepared polarizing plate sample with a slot die coater, passed through a 155 ° C. air circulating thermostat for 5 minutes, and the polarizing plate surface had a thickness of 15 μm. The pressure-sensitive adhesive layer was formed. On the formed pressure-sensitive adhesive layer, a separate film (film thickness: 38 μm) containing polyethylene terephthalate as a main component was bonded with a roll machine in a roll-to-roll manner.

(Punching of polarizing plate)
In order to bond the produced polarizing plate to a 42-inch liquid crystal display device, it was punched out with the following size.
・ Front side MD direction 929.8mm
TD direction 523.0mm
・ Rear side MD direction 523.0mm
TD direction 929.8mm
The polarizing plate punched out with the above size was put into an aluminum moisture-proof bag (manufactured by ADW Co., Ltd.) and sealed with a heat sealer set at a temperature of 180 ° C. The aluminum moisture-proof bag enclosing the polarizing plate was stored in an environment at a temperature of 25 ° C.

[Humidity dimensional change rate of polarizing plate sample]
In order to evaluate the expansion characteristic of the produced polarizing plate sample, the humidity dimensional change rate in the TD direction was measured.
Here, the humidity dimensional change rate of the polarizing plate sample was measured by the following method.
The absorption axis direction of the polarizing plate is the longitudinal direction (MD direction), and the direction orthogonal to the longitudinal direction is the transverse direction (TD direction). Using the width direction (TD direction) as a measurement direction, a film sample having a length of 12 cm in the measurement direction and a width of 3 cm was cut out. At this time, it cut out and measured in the state to which the separate film and the laminate film were attached. Pin holes were formed in the sample at intervals of 10 cm along the measurement direction, and after humidity conditioning at 25 ° C. and a relative humidity of 60% for 72 hours, the interval (length) of the pin holes was measured with a pin gauge. Next, after adjusting the humidity for 72 hours at 25 ° C. and 10% relative humidity, the distance between the pin holes was measured with a pin gauge. Next, the sample was conditioned for 72 hours at 25 ° C. and a relative humidity of 80%, and the distance between the pin holes was measured with a pin gauge. Using these measured values, the humidity dimensional change rate in the TD direction was calculated by the following equation.
(Formula) Humidity dimensional change rate in TD direction (%) = [{(length at 25 ° C., relative humidity 80%) − (length at 25 ° C., relative humidity 10%)} / (25 ° C., relative humidity 60 % Length)] × 100

[Production of liquid crystal display device]
The polarizing plates on the front side and the rear side were peeled off from a commercially available IPS type liquid crystal television (LG Electronics 42LA6900) to prepare an experimental liquid crystal cell. Next, the polarizing plate punched out to 42 inches from the aluminum moisture-proof bag was taken out and left in an environment of 25 ° C. and 60% for 72 hours. Then, the separate film was peeled off from the polarizing plate, and the polarizing plate was stuck one by one on the front side and the rear side of the prepared liquid crystal cell. At this time, the crossed Nicols were arranged so that the absorption axis of the front-side polarizing plate was in the longitudinal direction (left-right direction) and the transmission axis of the rear-side polarizing plate was in the longitudinal direction (left-right direction). The thickness of the glass used for the liquid crystal cell was 0.5 mm. The environment at this time was a temperature of 25 ° C. and a relative humidity of 60%. The films on the air side (the side far from the liquid crystal cell (viewing side and backlight side)) and the cell side (the side close to the liquid crystal cell) were configured as shown in Tables 2-5.

[Evaluation of expansion on liquid crystal cell]
Immediately after laminating the polarizing plate on the liquid crystal cell, place the gold scale on the polarizing plate on the front side and use a digital camera to photograph the scale of the gold scale and the edge of the polarizing plate, so that the polarizing plate on the liquid crystal cell The length in the TD direction was measured. The environment at this time was a temperature of 25 ° C. and a relative humidity of 60%. The elongation amount due to expansion was calculated by subtracting 523.0 mm, which is the length in the TD direction, of a 42-inch size polarizing plate from this length. When the expansion on the liquid crystal cell is 0.80 mm or more, the practical problem becomes large. The smaller the expansion, the better, preferably less than 0.80 mm, and more preferably less than 0.70 mm.

[Evaluation of the amount of protrusion from the glass edge]
Immediately after attaching the polarizing plate to the liquid crystal cell, place a gold scale in the TD direction of the polarizing plate on the front side so that the scale “0” comes to the glass edge of the liquid crystal cell, and use a digital camera to The scale and the edge of the polarizing plate were photographed. The scale of the gold scale that coincided with the edge of the polarizing plate was read, and the value of this scale was taken as the amount of protrusion from the edge of the glass. At this time, measurement was performed at two locations in the upper and lower directions in the TD direction, and the larger amount of protrusion was defined as the amount of protrusion from the glass edge. The sign when protruding from the glass edge was positive, and the sign when shrinking from the glass edge was negative. The amount of protrusion from the glass edge is preferably as small as possible, preferably less than 0.08 mm, more preferably less than 0.03 mm, and most preferably a negative value.

  These evaluation results are shown in Tables 2-5. From the results of Tables 2 to 5, it became clear that the optical film of the present invention is effective in reducing the expansion of the polarizing plate. This is presumably because the optical film has a high elastic modulus in the TD direction and a large anisotropy, thereby suppressing expansion due to moisture absorption of the transmission axis of the polarizer.

  A polarizing plate using an acrylic resin film on both the air side and the cell side has a low photoelastic property, so that a liquid crystal display device that produces beautiful display with little unevenness is obtained. Furthermore, the use of the same type of resin on both sides has an advantage that the curling of the polarizing plate is small because the mechanical properties (elastic modulus, thermal expansion coefficient) on both sides are close. Furthermore, by using the optical film of the present invention having an elastic modulus ratio (EMD / ETD) of less than 0.8 on at least one of the air side and the cell side, the expansion of the polarizing plate that easily expands in the TD direction is suppressed. Can do.

  A polarizing plate using an acetylcellulose-based film on the air side and an acrylic resin film on the cell side can produce a liquid crystal display device that produces beautiful display with less unevenness due to its low photoelastic characteristics. Further, by using an acetylcellulose-based film having high hardness on the air side, for example, the air-side surface of the backlight-side polarizing plate is hardly scratched even if rubbing with the backlight sheet occurs. Further, the air side surface of the polarizing plate on the viewing side is hardly damaged even when touched with a finger or wiped with cloth or paper. Furthermore, by using an acetylcellulose-based film with high moisture permeability for one of the protective films, not only a polarizing plate bonding method using a UV adhesive, but also a polarizing plate bonding method using a polyvinyl alcohol-based bonding method. Can be produced. Furthermore, by using the optical film of the present invention having an elastic modulus ratio (EMD / ETD) of less than 0.8 as the acrylic resin film on the cell side, the expansion of the polarizing plate that easily expands in the TD direction can be suppressed.

  A polarizing plate using a polyester (PET) film or a COP film on the air side and an acrylic resin film on the cell side has a low photoelastic property, so that a liquid crystal display device that produces beautiful display with little unevenness is obtained. Furthermore, by using a polyester film or COP film with low moisture permeability on the air side, water can be prevented from entering and exiting the polarizer, and unevenness due to deterioration of the polarizer can be suppressed. Furthermore, by using the optical film of the present invention having an elastic modulus ratio (EMD / ETD) of less than 0.8 as the acrylic resin film on the cell side, the expansion of the polarizing plate that easily expands in the TD direction can be suppressed.

  A polarizing plate using an acrylic resin film on the air side and a COP film on the cell side has a low moisture content characteristic of the COP film, so that a liquid crystal display device that produces beautiful display with little unevenness is obtained. Furthermore, retardation characteristics suitable for a VA liquid crystal display device can be obtained by stretching. Moreover, the unstretched COP film can obtain the low retardation characteristic which is an optical characteristic suitable for an IPS liquid crystal display device. By using the acrylic resin film on the air side, the water can enter and exit from the polarizer, and the occurrence of unevenness due to the deterioration of the polarizer can be suppressed. In addition, even when water enters the polarizer, the acrylic resin film has the property of slightly transmitting water, so it is possible to suppress the stay of water for a long time, and the degree of polarization decreases due to the deterioration of the polarizer. Can be suppressed. Furthermore, by using the optical film of the present invention having an elastic modulus ratio (EMD / ETD) of less than 0.8 as the air-side acrylic resin film, the expansion of the polarizing plate that easily expands in the TD direction can be suppressed.

[Production of 3D display device]
[Production of retardation film]
With reference to “Part 2” and “Part 5” in Example 1 of JP-A-2009-222001, Re = 137.5 nm and the direction of the slow axis is 45 degrees with respect to the direction of the long side of the pattern. A pattern retardation layer A patterned so that a part (first region) and a 135 degree part (second region) were repeated at a cycle of 300 μm was produced on a glass substrate. This was transcribe | transferred to the optical films 1-3 produced above (support body), and the phase difference films 1-3 which have the pattern phase difference layer A were created. At this time, transfer was performed so that the longitudinal direction of the pattern phase difference A and the MD directions of the optical films 1 to 3 were parallel. At this time, the repetition period direction of the pattern phase difference is orthogonal to the MD direction of the optical films 1 to 3.

  The retardation films 1 to 3 and the optical films 1 to 3 prepared above on both surfaces of the polarizer obtained above are subjected to corona treatment on the bonding surface with the polarizer and then bonded using an acrylic adhesive. It was.

(Production of 3D monitor)
The front polarizing plate of HPL02065 (manufactured by Hewlett Packard) was peeled off, and a polarizing plate using the films of Examples and Comparative Examples as a protective film was bonded instead. At this time, the outer side (viewing side) and inner side (liquid crystal cell side) films were configured as shown in Table 6.

(Evaluation of dependency of crosstalk on environmental humidity)
After the 3D monitor prepared above was left in an environment of temperature 25 ° C. and humidity 60% for 48 hours, the right eye pixel displayed a white pattern and the left eye pixel displayed a black pattern, and the spectral radiance meter (SR-3 Topcon The brightness was measured through circular polarizing glasses for the right eye / left eye.
The luminance when passing through the right-eye circular polarizing glasses is Y_RR, and the luminance when passing through the left-eye circular polarizing glasses is Y_RL.
Since the 3D feeling is lost when the right-eye image enters the left eye and the left-eye image enters the right eye, the degree of crosstalk is defined as CRO = (Y_RR-Y_RL) / (Y_RR + Y_RL) and evaluated.
Further, after the 3D monitor produced as described above was left for 48 hours in an environment of a temperature of 25 ° C. and a humidity of 10%, the degree of crosstalk was similarly evaluated.
CRO in a temperature 25 ° C./humidity 60% environment was CRO_60%, CRO in a temperature 25 ° C./humidity 10% environment was CRO_10%, and evaluation was performed according to the following criteria based on a value of 100 * CRO_10% / CRO_60%.
A: 95% or more
B: Less than 95% to 92.5% or more C: Less than 92.5% to 90% or more
D: Less than 90%
“A” is most preferred, “B” is next preferred, and “C” is next preferred.
The results are shown in Table 6 below. From the results shown in Table 6, it became clear that the optical film of the present invention is effective in reducing crosstalk during continuous lighting of a 3D display. This is presumably because the dimensional change of the support over time was suppressed.

Claims (7)

Contains acrylic resin having lactone ring structure in main chain and acrylonitrile-styrene resin, tensile modulus (EMD) in machine direction (MD direction) and tensile modulus (ETD) in direction perpendicular to machine direction (TD direction) Is an optical film satisfying the relationship of the formula (1).
Formula (1) EMD / ETD <0.8 The tensile elastic modulus in the machine direction (MD direction) of the optical film is 1.2 × 10 ^{9 to} 4.0 × 10 ⁹ N / m ² , and the tensile elastic modulus in the direction perpendicular to the machine direction (TD direction) is 1.5 a ^{× 10 9 ~5.0 × 10 9 N} / m 2, the optical film according to claim 1. The retardation value Re (nm) in the film plane represented by the formulas (i) and (ii) of the optical film and the retardation value Rth (nm) in the film thickness direction are the formulas (iii) and (iv). The optical film according to claim 1 or 2, which is satisfied.
(I) Re = (nx−ny) × d
(Ii) Rth = ((nx + ny) / 2−nz) × d
(Iii) 0 ≦ Re <20
(Iv) | Rth | ≦ 25
In the formula, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the film (Nm).   The surface of the optical film is provided with at least one of a pattern retardation layer, a λ / 4 layer, a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, an optically anisotropic layer, and an easy adhesion layer. The optical film of any one of 1-3.   The polarizing plate which has a polarizer and the optical film of any one of Claims 1-4 on the single side | surface of a polarizer at least.   The polarizing plate of Claim 5 which has the optical film of any one of Claims 1-4 on both surfaces of a polarizer.   A liquid crystal display device comprising at least one polarizing plate according to claim 5.