KR20120041099A - Adhesive polarization plate and image display - Google Patents

Abstract

PURPOSE: An adhesion type polarizing plate and an image display device are provided to remove phase difference change of a transparent protective film and the phase difference change of an adhesive layer on the entire surface of the adhesion type polarizing plate. CONSTITUTION: An adhesion type polarizing plate(10) has a first transparent protective film(2) on one side of a polarizer(1). An adhesive layer(5) is formed on the transparent protective film. An adhesive layer is interposed between the polarizer and the first transparent protective film for lamination. A second transparent protective film(3) is laminated on the opposite side to the side on which the first transparent protective film of the polarizer is laminated. The adhesive layer contains acryl based polymer which contains acrylate as a monomer unit.

Description

Adhesive polarizer and image display device {ADHESIVE POLARIZATION PLATE AND IMAGE DISPLAY}

The present invention relates to an adhesive polarizing plate having an adhesive layer laminated on at least one side of the polarizing plate, and an image display device using the same.

The liquid crystal display device has a configuration in which a liquid crystal panel in which a polarizing plate is disposed on at least one side of a liquid crystal cell is combined with a light source such as a backlight, and in general, the liquid crystal cell and the polarizing plate are laminated via an adhesive layer. Moreover, in the organic electroluminescence display, the structure which bonded together a circularly polarizing plate via the adhesive layer on the visual recognition side of a cell is employ | adopted for the purpose of shielding the mirror surface reflection of external light. In the case where an image display device using such a polarizing plate is provided to be used in practice, light leakage may occur at an end portion of the screen, especially when used in a high temperature or high humidity environment.

The light leakage accompanying such environmental changes is thought to be due to the change in the dimensions of each member due to changes in temperature, humidity, etc., and the phase difference of each member constituting the polarizing plate due to the stress at the interface. do. That is, although the polarizing plate generally has the structure which the transparent protective film laminated | stacked through the adhesive bond layer to the polarizer, the interface of the said transparent protective film and a polarizer, or the interface with the other member bonded to the transparent protective film with environmental changes. It is thought that the cause is caused by the occurrence of a stress and a change in retardation characteristics of the transparent protective film due to photoelastic birefringence caused by the stress. In particular, since the dimensional change of each member becomes larger at the end of the screen than in the center of the screen, light leakage at the end tends to be remarkable.

In addition, with the recent increase in size of the image display device and the trend of higher luminance, the temperature inside the image display device tends to rise due to heat generation of the light source. Moreover, the use of thin image display apparatuses, such as a liquid crystal display device and an organic electroluminescence display, is diversifying, and there exists a tendency for the opportunity to be used under severe environments, such as high temperature, high humidity, to increase. Therefore, the light leakage of the screen end part with environmental changes becomes easier to see.

It is proposed to reduce the phase difference change of a transparent protective film using the transparent protective film with a small absolute value of a photoelastic coefficient from a viewpoint of suppressing such light leakage of the screen edge part (for example, patent document 1). Moreover, the difference of the tensile elasticity modulus of the machine direction at the time of manufacture of a transparent protective film and the direction perpendicular | vertical to a machine direction is made small (for example, patent document 2), and the product of the linear expansion coefficient of a transparent protective film and the elasticity modulus of an adhesive layer is predetermined. By making it into the range of (for example, patent document 3, 4), the method of reducing the phase difference change of a transparent protective film, etc. are also proposed.

Japanese Unexamined Patent Publication No. 2000-352619 Japanese Laid-Open Patent Publication 2008-217021 Japanese Unexamined Patent Publication No. 2002-122739 Japanese Unexamined Patent Publication No. 2002-122740

As described in Patent Document 1, the absolute value of the photoelastic coefficient of the transparent protective film is preferably small from the viewpoint of reducing the phase difference change of the transparent protective film caused by the environment and suppressing light leakage at the edge of the screen. As a result, the problem of light leakage can be considered to be solved by using a transparent protective film having a photoelastic coefficient of almost zero. However, according to the studies by the present inventors, it was found that even when a transparent protective film having a small absolute value of the photoelastic coefficient was used, light leakage at the screen end with the use environment occurred.

In view of such a problem, an object of this invention is to provide the adhesive polarizing plate which does not produce the light leakage of an image display apparatus well also by the change of a use environment, and an image display apparatus using the same.

MEANS TO SOLVE THE PROBLEM As a result of examining the cause which a light leak generate | occur | produces even when the transparent protective film with a small photoelastic coefficient is used, the present inventors discovered the new knowledge that the situation of light leakage changes by changing the kind of adhesive layer which bonds a polarizing plate and a liquid crystal cell. Figured out. And as a result of earnestly examining based on the presumed principle that the light leakage in the use environment of an image display apparatus from the said knowledge originates not only in the retardation change of a transparent protective film but also in retardation generate | occur | producing in the adhesive layer, It discovered that light leakage can be suppressed by the combination of the transparent protective film and adhesive bond layer of, and came to this invention.

This invention relates to the adhesive polarizing plate in which the transparent protective film is laminated | stacked on the at least single side | surface of a polarizer, and the adhesive layer was laminated | stacked on the surface of the side which is not laminated | stacked with the polarizer of the said transparent protective film. The said adhesive layer is formed of the adhesive containing the acrylic polymer which contains an alkyl (meth) acrylate and the (meth) acrylate which has an aromatic ring structure as a monomer unit.

The absolute value of the photoelastic coefficient X (m <2> / N) of the said transparent protective film is 50x10 <^-12> or less. Moreover, when content of the (meth) acrylate monomeric unit which has an aromatic ring structure in the acrylic polymer which comprises the said adhesive layer is made into Y%, X and Y satisfy | fill the following.

-1 × 10 ¹¹ X + 3≤Y≤-1 × 10 ¹¹ X + 23

In the pressure-sensitive adhesive polarizing plate of the present invention, the transparent protective film is at least one resin selected from the group consisting of acrylic resins, cyclic olefin resins, phenylmaleimide resins, cellulose resins, and modified polycarbonate resins. It is preferable to contain.

Moreover, this invention relates to the image display apparatus in which the said adhesive polarizing plate is used.

In the adhesive polarizing plate of this invention, the acrylic polymer which comprises an adhesive layer contains the (meth) acrylate monomeric unit (component B) which has a predetermined amount of aromatic ring structure. Content Y of B component is determined according to the value of the photoelastic coefficient X of a transparent protective film, and when the phase difference value of a transparent protective film changes by environmental changes, such as heating, an adhesive layer has the opposite code | symbol to a transparent protective film. Is adjusted to generate a phase difference change of.

According to such a structure, in the vicinity of the screen edge part where the phase difference change of a transparent protective film is large, the phase difference change of an adhesive layer also becomes large (However, the code of the phase difference change of an adhesive layer is opposite to the code of the phase difference change of a transparent protective film. ), The retardation change of the transparent protective film and the retardation change of the pressure-sensitive adhesive layer are eliminated in the entire in-plane of the adhesive polarizing plate. Therefore, the image display apparatus in which the adhesive polarizing plate of the present invention is bonded is capable of image display with little light leakage even when exposed to a heating environment or the like.

1 is a schematic cross-sectional view of a pressure-sensitive adhesive polarizing plate according to an embodiment of the present invention.
2 is a schematic cross-sectional view of an image display device according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated, referring drawings. As shown in FIG. 1, the adhesive polarizing plate 10 of the present invention has a first transparent protective film 2 on one side of the polarizer 1, and an adhesive layer 5 is formed on the transparent protective film 2. It is. The polarizer 1 and the 1st transparent protective film 2 are laminated | stacked through the adhesive bond layer which is not shown in figure. Moreover, it is preferable that the 2nd transparent protective film 3 is laminated | stacked on the surface on the opposite side to the side where the 1st transparent protective film 2 of the polarizer 1 was laminated | stacked through the adhesive bond layer which is not shown in figure.

When forming the image display apparatus 100 using the adhesive polarizing plate 10 of this invention, as shown in FIG. 2, the surface of the side where the 1st transparent protective film 2 is arrange | positioned is the adhesive layer 5 It is bonded to the image display cell 20 via the above. That is, the 1st transparent protective film and the adhesive layer 5 are arrange | positioned between the image display cell 20 and the polarizer 1. In addition, although the adhesive polarizing plate 10 is bonded to both surfaces of the image display cell 20 in FIG. 2, the adhesive polarizing plate may be bonded only to the single side | surface of the image display cell 20. As shown in FIG.

[Polarizer]

The polarizer 1 is not specifically limited, Various things can be used. As a polarizer, the dichroic substance of an iodine or a dichroic dye is made to adsorb | suck to hydrophilic polymer films, such as a polyvinyl alcohol-type film, a partially formalized polyvinyl alcohol-type film, and an ethylene-vinyl acetate copolymerization partial saponification film, for example. And polyene oriented films such as monoaxially stretched, dehydrated polyvinyl alcohol and dehydrochloric acid treated polyvinyl chloride. Among these, the polarizer which consists of dichroic substances, such as a polyvinyl alcohol-type film and iodine, is preferable. The thickness of these polarizers is not particularly limited, but generally 5? It is about 80 micrometers.

The polarizer which dyed the polyvinyl alcohol-type film with iodine and uniaxially stretched, for example, dyed the polyvinyl alcohol by immersing it in the aqueous solution of iodine, and the 3? It can manufacture by extending | stretching 7 times. If necessary, it can also be immersed in aqueous solution, such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride, etc. If necessary, the polyvinyl alcohol-based film may be dipped in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, the contamination of the polyvinyl alcohol-based film with the anti-blocking agent can be washed, and the polyvinyl alcohol-based film is swelled to prevent nonuniformity such as staining. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be dyed with iodine after stretching. It can extend | stretch also in aqueous solution, such as boric acid and potassium iodide, or a water bath.

[Transparent Protective Film]

As the 1st transparent protective film 2 arrange | positioned at one main surface of a polarizer, the thing whose absolute value of a photoelastic coefficient is 50 * 10 <^-12> m <2> / N or less is used. When the photoelastic coefficient is excessively large, there is a tendency that nonuniformity tends to occur in image display when stress is added to the first protective film. In addition, a photoelastic coefficient can be calculated | required from the inclination which measured the phase difference value at the time of giving a predetermined tension to a film, and plotted the stress and phase difference value. The sign of the photoelastic coefficient positively defines that the phase difference increases when a tensile stress is applied, and negative that the phase difference decreases.

(material)

The material for forming the first transparent protective film is not particularly limited as long as the photoelastic coefficient is within the above range, but is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like. As the material for forming the first transparent protective film, a cyclic polyolefin resin, an acrylic resin, a phenylmaleimide resin, a cellulose resin, a modified polycarbonate resin, or the like is preferably used.

The said cyclic polyolefin type resin is generic name of resin which superpose | polymerizes a cyclic olefin as a polymerization unit, For example, Unexamined-Japanese-Patent No. 1-240517, Unexamined-Japanese-Patent No. 3-14882, Unexamined-Japanese-Patent No. The resin described in Unexamined-Japanese-Patent No. 3-122137 etc. is mentioned. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins with α-olefins such as ethylene and propylene (typically random copolymers), and unsaturated carbohydrates Graft modified products modified with an acid or a derivative thereof and their hydrides. As a specific example of a cyclic olefin, a norbornene-type monomer is mentioned.

Norbornene-based monomers include, for example, norbornene, and alkyl and / or alkylidene substituents thereof. Moreover, as cyclic polyolefin type resin, other cyclic olefins which can be ring-opening-polymerized other than the above can be used together in the range which does not impair the objective of this invention.

Various products are commercially available as such a cyclic polyolefin resin. As a specific example, Nippon Xeon make brand names "Zeonex", "Ze onor", JSR make brand name "Arton", TICONA make brand name "Topas", Mitsui Chemical make brand name "Apel" is mentioned.

Examples of the acrylic resin include poly (meth) acrylic acid esters such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, and methyl methacrylate-acrylic acid Ester- (meth) acrylic acid copolymer, methyl (meth) acrylate-styrene copolymer (such as MS resin), polymer having an alicyclic hydrocarbon group (eg, methyl methacrylate-cyclohexyl copolymer, methacrylic) Methyl acid- (meth) acrylic acid norbornyl copolymer, etc.) is mentioned. Preferably, poly (meth) acrylic-acid C1-6 alkyl, such as methyl poly (meth) acrylate, is mentioned. More preferably, methyl (meth) acrylate type resin which makes methyl (meth) acrylate the main component (50-100 weight%, Preferably 70-100 weight%) is mentioned.

As a specific example of an acrylic resin, For example, the acrylic resin which has a ring structure in the molecule | numerator of Mitsubishi Rayon-made acripet VH, an acripett VRL20A, Unexamined-Japanese-Patent No. 2004-70296, a crosslinking in a molecule | numerator, or a ring in a molecule | numerator High Tg acrylic resin obtained by a oxidization reaction is mentioned.

Moreover, the (meth) acrylic-type resin which has a lactone ring structure can also be used preferably as acrylic resin. (Meth) acrylic-type resin which has a lactone ring structure is preferable at the point which has high mechanical strength by high heat resistance, high transparency, and biaxial stretching.

As (meth) acrylic-type resin which has a lactone ring structure, Unexamined-Japanese-Patent No. 2000-230016, Unexamined-Japanese-Patent No. 2001-151814, Unexamined-Japanese-Patent No. 2002-120326, Unexamined-Japanese-Patent No. 2002-254544, Japan (Meth) acrylic-type resin which has a lactone ring structure as described in Unexamined-Japanese-Patent No. 2005-146084 etc. is mentioned.

As phenyl maleimide-type resin, what superposed | polymerized the monomer which the substituted or unsubstituted phenyl group couple | bonded with the nitrogen atom of maleimide is mentioned. As a raw material monomer of phenyl maleimide-type resin, for example, N-phenyl maleimide, N- (2-methylphenyl) maleimide, N- (2-ethylphenyl) maleimide, N- (2-propylphenyl) malee Mid, N- (2-isopropylphenyl) maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2,6-dipropylphenyl) maleimide, N- (2,6-diiso Propylphenyl) maleimide, N- (2-methyl-6-ethylphenyl) maleimide, N- (2-chlorophenyl) maleimide, N- (2,6-dichlorophenyl), N- (2-bromo Phenyl) maleimide, N- (2,6-dibromophenyl) maleimide, N- (2-biphenyl) maleimide, N- (2-cyanophenyl) maleimide, and the like. Such a maleimide monomer can be obtained from Tokyo Chemical Industry Co., Ltd., for example.

The phenylmaleimide resin may be copolymerized with monomers other than the phenylmaleimide monomer for the purpose of improving brittleness, molding processability, heat resistance, and the like. For example, olefins such as ethylene, propylene, 1-butene, 1,3-butadiene, 2-methyl-1-butene, 2-methyl-1-pentene, 1-hexene, acrylonitrile, methyl acrylate, methacryl Methyl acid, maleic anhydride, vinyl acetate, etc. are mentioned. Such a phenylmaleimide-olefin copolymer can be obtained, for example, from Tosoh Corporation.

As said cellulose resin, ester of a cellulose and a fatty acid is preferable. Specific examples of such cellulose esters include triacetyl cellulose, diacetyl cellulose, tripropionyl cellulose, dipropionyl cellulose and the like. Among these, triacetyl cellulose is particularly preferable.

Moreover, a commercial item can also be used as a film containing cellulose resin. As an example of the commercial item of a triacetyl cellulose film, Fujifilm manufacture brand names "UV-50", "UV-80", "SH-80", "TD-80U", "TD-TAC", "UZ-TAC" Konica Minolta "KC series", etc. are mentioned.

As said modified polycarbonate resin, in addition to 4,4'- (propane-2, 2-diyl) diphenol (bisphenol A) as a bisphenol component, it contains the bisphenol component which expresses negative birefringence as a monomer unit, and contains a photoelastic coefficient The thing which made it small is mentioned. As a bisphenol component which expresses the negative birefringence which comprises such a modified polycarbonate, the bisphenol which has a fluorene structure is mentioned, for example.

As such a modified polycarbonate resin, it is described in Unexamined-Japanese-Patent No. 2001-194530, Unexamined-Japanese-Patent No. 2001-139676, WO 01/081959 international publication brochure, WO 2006/041190 international publication brochure, etc., for example. Polycarbonate resins are preferably used.

A commercial item can also be used as a film containing modified polycarbonate resin. As such a modified polycarbonate film, Teijin Chemical make brand name "Pure Ace WR series" etc. are mentioned, for example.

Although the 1st transparent protective film 2 may be an optically anisotropic film which does not have retardation substantially, and may be an optically anisotropic film which has retardation, since it is arrange | positioned between the image display cell 20 and the polarizer 1, retardation It is preferable that the nonuniformity is small and the optical uniformity is high. When using an optically anisotropic film as a 1st transparent protective film, a 1st transparent protective film can have a role as a protective film of a polarizer, and a role as a retardation plate. For example, when using the adhesive polarizing plate of this invention for a liquid crystal display device, a 1st protective film also serves as an optical compensation film. Moreover, when using the adhesive type polarizing plate of this invention for an organic electroluminescence display, it can be set as a circularly polarizing plate by using a 1/4 wavelength plate as a 1st protective film.

Although the thickness of a 1st transparent protective film can be suitably determined, Generally, it is 1? It is about 500 micrometers. In particular, 5? 200 μm is preferred.

When an adhesive type polarizing plate is equipped with the 2nd transparent protective film 3, a 2nd protective film is not specifically limited, The transparent film excellent in transparency, mechanical strength, thermal stability, moisture barrier, etc. is used preferably. As a material which forms a 2nd protective film, what was illustrated as a material which forms a 1st protective film, etc. can be used preferably.

The surface which does not adhere | attach the polarizer of a 2nd transparent protective film may be the thing which performed the process for the objective of a hard-coat layer, an antireflection process, sticking prevention, and diffused or antiglare. An antireflection layer, a sticking prevention layer, a diffusion layer, an antiglare layer, etc. can be formed in a transparent protective film itself, and can also be formed as an optical layer separately from a transparent protective film.

It is preferable that the polarizer 1 and the transparent protective films 2 and 3 be laminated | stacked using an adhesive agent. As the adhesive, an aqueous adhesive or the like is preferably used. As an aqueous adhesive agent, an isocyanate adhesive, a polyvinyl alcohol adhesive, a gelatin adhesive, a vinyl latex type, an aqueous polyurethane, an aqueous polyester, etc. can be illustrated. In addition, at the time of bonding of a polarizer and a transparent protective film, an activation process can be given to a transparent protective film. Various methods can be adopted for the activation treatment, and for example, saponification treatment, corona treatment, low pressure UV treatment, plasma treatment and the like can be adopted.

[Adhesive Layer]

The adhesive layer 5 is formed of an adhesive. As the base polymer of the pressure-sensitive adhesive, an acrylic polymer containing an alkyl (meth) acrylate monomer unit (component A) and a (meth) acrylate monomer unit (component B) having an aromatic ring structure is used. In addition, in this specification and a claim, description of "(meth) acrylate" means "acrylate and / or methacrylate."

The content of the (meth) acrylate (component B) having an aromatic ring structure in the acrylic polymer as the base polymer is Y (%) with respect to the photoelastic coefficient X (m 2 / N) of the first transparent protective film, 1 × 10 ¹¹ X + 3 ≦ Y ≦ -1 × 10 ¹¹ X + 23 is satisfied.

In this invention, content Y of B component is made into the said range so that the absolute value of the phase difference change of the adhesive polarizing plate in the case of exposure to a heating environment may become small. The smaller the absolute value of the phase difference change of the pressure-sensitive adhesive polarizing plate, the better. Specifically, it is preferable that the phase difference change is within ± 2 nm, and more preferably ± 1 nm.

Thus, from the viewpoint of reducing the phase difference change of the pressure-sensitive adhesive polarizing plate to suppress light leakage at the screen end of the image display device, the content Y of (meth) acrylate (component B) having an aromatic ring structure in the acrylic polymer. (%) Is preferably -1 × 10 ¹¹ X + 4, more preferably -1 × 10 ¹¹ X + 5 or more, and even more preferably -1 × 10 ¹¹ X + 6 or more. Moreover, it is preferable that Y is -1 * 10 <^11> X + 21 or less, It is more preferable that it is -1 * 10 <^11> X + 20 or less, It is still more preferable that it is -1 * 10 <^11> X + 19 or less. Thus, by adjusting content Y of the B component in an acrylic polymer according to the value of the photoelastic coefficient X of a 1st transparent protective film, the photoelastic birefringence of a transparent protective film disappears by birefringence of an adhesive layer, and The change in phase difference can be made small. Further, the first transparent absolute value of photoelastic coefficient X (㎡ / N) of the protective film was 30 × 10 ^-12 or less is preferable, and 20 × 10 ^-12 or less, and more preferably more preferably, not more than 10 × 10 ^-12 Do.

Carbon number of the alkyl group of the alkyl (meth) acrylate (component A) in the acrylic polymer which forms an adhesive layer is 1? 18 degree, Preferably it is C1-C? 9 and an alkyl group may be either a linear or branched chain. As a specific example of alkyl (meth) acrylate, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) Acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylic The rate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc. are mentioned. These may be used alone or in combination. The average carbon number of these alkyl groups is 4? It is preferable that it is 12.

As an aromatic ring structure of the (meth) acrylate (component B) which has an aromatic ring structure in the acrylic polymer which forms an adhesive layer, a benzene ring, a naphthalene ring, a thiophene ring, a pyridine ring, a pyrrole ring, a furan ring, etc. Can be mentioned. Examples of the (meth) acrylate having an aromatic ring structure include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenoxy-2-hydroxypropyl (meth) acrylate, and phenolethylene oxide modification. (Meth) acrylate, 2-naphthoxyethyl (meth) acrylate, 2- (4-methoxy-1-naphthoxy) ethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxyethylene glycol (Meth) acrylate, thiophenyl (meth) acrylate, pyridyl (meth) acrylate, pyrrolyl (meth) acrylate, phenyl (meth) acrylate, polystyryl (meth) acrylate, etc. are mentioned.

As described above, the reason why the change in retardation can be made small by having the (meth) acrylate component (component B) having a predetermined amount of aromatic ring structure is not clear, but the component B has high polarization in the side chain. Since it has an aromatic ring structure, it is presumed that the expression tendency of birefringence is significantly different from the alkyl (meth) acrylate component (component A).

Moreover, the acrylic polymer which comprises an adhesive may contain another monomeric unit (component C) in addition to the said A component and B component as a monomer unit.

As said C component, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth), for example Acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate or (4-hydroxymethylcyclohexyl) -methylacrylate Hydroxyl group-containing monomers such as these; Carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; Acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; Caprolactone adducts of acrylic acid; Sulfonic acid group-containing monomers such as allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamide propanesulfonic acid, and sulfopropyl (meth) acrylate; Phosphoric acid group containing monomers, such as 2-hydroxyethyl acryloyl phosphate, etc. are mentioned.

Moreover, a nitrogen containing vinyl monomer is mentioned as said C component. For example, maleimide; (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl (N-substituted) amide monomers such as (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth) acrylamide; Alkylaminoalkyl (meth) acrylates, such as aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N- dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate Monomers; Alkoxy alkyl (meth) acrylate type monomers, such as methoxy ethyl (meth) acrylate and ethoxy ethyl (meth) acrylate; Such as N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, and N- (meth) acryloyl-8-oxyoctamethylene succinimide Succinimide type monomers etc. are also mentioned as an example of the monomer for modification.

Moreover, as said C component, Vinyl monomers, such as vinyl acetate, a vinyl propionate, N-vinyl carboxylic acid amides, styrene, (alpha) -methylstyrene, and N-vinyl caprolactam; Nitrile monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; Glycol-based acrylic ester monomers such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, and methoxy polypropylene glycol (meth) acrylate; (Meth) acrylate type monomers, such as fluorine (meth) acrylate, silicone (meth) acrylate, and 2-methoxyethyl acrylate, can also be used.

The said C component can be used arbitrarily in order to modify a base polymer. The said C component can use 1 type (s) or 2 or more types. The proportion of the C component is preferably 10% by weight or less, more preferably 6% by weight or less, as the monomer unit in the acrylic polymer. When the ratio of C component exceeds 10 weight%, the softness | flexibility as an adhesive may be inhibited.

As said C component, since the adhesiveness is favorable, the monomer containing a carboxyl group, especially acrylic acid is used preferably. When using the monomer containing a carboxyl group, the ratio is 0.1? About 10% by weight, preferably 0.5? 8% by weight, more preferably 1? 6 wt%. Moreover, a hydroxyl group containing monomer is used preferably at the point which can become a crosslinking point with an isocyanate crosslinking agent. When using a hydroxyl group containing monomer, the ratio is 0.1? About 10% by weight, preferably 0.5? 8% by weight, more preferably 1? 6 wt%.

The said acrylic polymer can be manufactured by various well-known methods, For example, radical polymerization methods, such as a bulk polymerization method, a solution polymerization method, and suspension polymerization method, can be selected suitably. As a radical polymerization initiator, various well-known thing of azo type and a peroxide type can be used. The reaction temperature is usually 50? 80 degreeC, reaction time is 1? 8 hours. Moreover, the solution polymerization method is preferable also in the said manufacturing method, and ethyl acetate, toluene, etc. are generally used as a solvent of an acryl-type polymer. The solution concentration is usually 20? It is about 80% by weight. Moreover, an acryl-type polymer can be obtained as an aqueous emulsion.

The weight average molecular weight of the acrylic polymer is 1 million? It is preferable that it is 3 million. The weight average molecular weight of the acrylic polymer exceeds 2 million? It is more preferable that it is 3 million, and 210 million? It is more preferable that it is 2.7 million. When the weight average molecular weight is too small, birefringence to the extent that the birefringence of the transparent protective film is eliminated does not occur in the pressure-sensitive adhesive layer, and the suppression of light leakage may be insufficient. On the other hand, when a weight average molecular weight exceeds 3 million, there exists a tendency for adhesiveness to fall.

The adhesive which forms the adhesive layer of this invention may contain a crosslinking agent in addition to the said acrylic polymer which is a base polymer. By a crosslinking agent, adhesiveness and durability with an optical film can be improved, and reliability at high temperature and the maintenance of the shape of the adhesive itself can be aimed at. As a crosslinking agent, an isocyanate type, an epoxy type, a peroxide type, a metal chelate type, an oxazoline type, etc. can be used suitably. These crosslinking agents can be used 1 type or in combination of 2 or more type. As a crosslinking agent, the crosslinking agent containing the functional group which shows the reactive group with a hydroxyl group is preferable, and an isocyanate type crosslinking agent is especially preferable.

The usage-amount of a crosslinking agent is 10 weight part or less with respect to 100 weight part of base polymers, Preferably it is 0.01? 5 parts by weight, more preferably 0.02? 3 parts by weight. When the use ratio of a crosslinking agent exceeds 10 weight part, crosslinking will progress excessively and there exists a tendency for adhesiveness to fall.

In the pressure-sensitive adhesive, fillers, pigments, colorants, fillers, antioxidants, ultraviolet absorbers, silane coupling agents, etc., made of tackifiers, plasticizers, glass fibers, glass beads, metal powders, and other inorganic powders, may be used as necessary. Various additives can also be used suitably in the range which does not deviate from the objective. Moreover, it is good also as an adhesive layer etc. which contain microparticles | fine-particles and show light diffusivity.

As said additive, a silane coupling agent is preferable. As the silane coupling agent, a silane having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc. Coupling agent; 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl- Amino group-containing silane coupling agents such as N- (1,3-dimethylbutylidene) propylamine; (Meth) acryl-group containing silane coupling agents, such as 3-acryloxypropyl trimethoxysilane and 3-methacryloxypropyl triethoxysilane; Isocyanate group containing silane coupling agents, such as 3-isocyanate propyl triethoxysilane; 3-chloropropyltrimethoxysilane; Acetoacetyl group containing trimethoxysilane etc. are mentioned. Although a silane coupling agent may be used individually by 1 type, and 2 or more types are mixed and used, the compounding quantity of a silane coupling agent is 0.01 to 100 weight part of acrylic polymers. 2 parts by weight, preferably 0.02? 1 part by weight.

[Formation of Adhesive Type Polarizing Plate]

The adhesive polarizing plate 10 of this invention can be manufactured by forming an adhesive layer with the said adhesive on the 1st transparent protective film 2. The formation method of an adhesive layer is not specifically limited, The method of apply | coating and drying an adhesive solution on a transparent protective film by appropriate development methods, such as a casting method and a coating method, the method of transferring by the release sheet which formed the adhesive layer, etc. are mentioned. Can be. The coating method may be a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, a spray method, or the like. After apply | coating an adhesive solution, the adhesive layer of predetermined thickness is obtained by volatilizing a solvent and water in a drying process.

The thickness of an adhesive layer can be suitably determined according to a use purpose, adhesive force, etc., and generally 1? 500 micrometers, Preferably it is 1? 50 μm. Also 1? 40 micrometers is preferable, Furthermore, 5? 30 micrometers is preferable, and especially 10? 25 μm is preferred. When it is thinner than 1 µm, durability deteriorates, and when it is thick, lifting or peeling due to foaming or the like tends to occur, and appearance tends to be poor.

Moreover, formation of an adhesive layer can apply | coat UV curable adhesive syrup on a release film, and can form the adhesive layer containing the said acrylic polymer by irradiating radiation, such as an electron beam or UV. At this time, since the adhesive contains a crosslinking agent, the reliability at high temperature and the shape of the adhesive itself can be achieved.

The crosslinking of the pressure-sensitive adhesive layer can be carried out in the drying step or the UV irradiation step, and a crosslinking mode in which crosslinking is promoted by aging by a warm state or room temperature standing after drying can be selected.

With respect to the exposed surface of the pressure-sensitive adhesive layer 5 of the pressure-sensitive adhesive polarizing plate of the present invention, the separator is temporarily attached to the surface of the pressure-sensitive adhesive layer for the purpose of preventing contamination of the pressure-sensitive adhesive layer and the like until the adhesive surface 5 is provided to be practical. It is preferred to be covered. Thereby, contact with an adhesive layer can be prevented in a usual handling state. Examples of the separator include a plastic film, rubber sheet, paper, cloth, nonwoven fabric, net, foam sheet, metal foil, and a laminate of appropriate type such as their laminate, silicone, long chain alkyl, fluorine, molybdenum sulfide and the like. The appropriate thing according to the past, such as what coat-processed with the appropriate peeling agent of can be used.

[Image display device]

The adhesive polarizing plate of this invention can be used suitably for various image display apparatuses, such as a liquid crystal display device and an organic electroluminescence display. The image display apparatus of this invention can be set as the structure similar to the conventional image display apparatus except using the adhesive polarizing plate of this invention.

A liquid crystal display device can be manufactured, for example, by appropriately assembling each component such as a liquid crystal cell, an optical member such as the polarizing plate of the present invention, and an illumination system (backlight, etc.) as necessary, and inserting a driving circuit. have. The configuration of the liquid crystal display device is not particularly limited as long as the pressure-sensitive adhesive polarizing plate of the present invention is used on one side or both sides of the liquid crystal cell.

When forming a liquid crystal display device in which a polarizing plate is disposed on both the viewing side and the light source side of a liquid crystal cell, as in the transmission type liquid crystal display device, from the viewpoint of suppressing light leakage, the adhesive polarizing plate of the present invention is provided on both sides of the liquid crystal cell. The arrangement arranged is preferably employed.

An organic electroluminescence display can be manufactured by arrange | positioning the adhesive polarizing plate of this invention to the visual recognition side of an organic electroluminescent cell (organic light emitting layer), for example. In particular, as described above, by using a quarter wave plate as the first transparent protective film, it is possible to suppress a decrease in visibility due to reflection of external light. In addition, you may arrange | position a 1/4 wavelength plate separately on the polarizing plate of this invention, and set it as the circular polarizing plate on the visual recognition side of an organic EL cell, without using a quarter wavelength plate as a transparent protective film.

The image display device of the present invention is used for any suitable use. Its use is, for example, home appliances such as OA devices such as desktop PCs, laptops, copiers, mobile phones, watches, digital cameras, portable digital assistants (PDAs), portable game machines, video cameras, televisions, microwave ovens, and the like. Nursing and medical devices such as electric appliances, back monitors, car navigation system monitors, car equipments such as car audio, exhibition equipment such as information monitors for commercial stores, security devices such as surveillance monitors, nursing monitors, medical monitors, etc. Etc. can be mentioned.

Example

Although an Example and a comparative example are given to the following and this is further demonstrated, this invention is not limited only to these Examples.

Example 1

(Preparation of Adhesive)

In a four-necked flask equipped with a cooling tube, a stirring blade, and a thermometer, 97 parts by weight of butyl acrylate, 5 parts by weight of benzyl acrylate, and 0.1 parts by weight of 2,2-azobisisobutyronitrile were added together with 140 parts by weight of ethyl acetate. After sufficient nitrogen substitution, it was made to react at 55 degreeC for 8 hours, stirring under nitrogen stream, and the weight average molecular weight 2 million acrylic polymer solution was obtained. 0.45 weight part of crosslinking agents (Nippon Polyurethane brand name "Colonate L") and 0.1 weight part of silane coupling agents (Shin-Etsu Silicone make brand name "KBM403") are added to solid content of 100 weight part of this acrylic polymer solution, and it is an adhesive The solution was prepared.

(Formation of Adhesive Layer)

The obtained adhesive solution was apply | coated by the reverse roll coating method so that the thickness of the adhesive layer after drying might be set to 20 micrometers on the separator which consists of a polyester film (38 micrometers in thickness) which performed the mold release process, and heat-processes at 155 degreeC for 3 minutes. The solvent was volatilized and the adhesive layer was obtained.

(Production of polarizing plate)

A polyvinyl alcohol-based polarizer was stretched and conveyed while dyeing a polymer film containing polyvinyl alcohol having an average polymerization degree of 2400 and a saponification degree of 99.9 mol% between rolls having different circumferential speeds. First, it was immersed in a 30 degreeC water bath for 1 minute, extending | stretching a polyvinyl alcohol film 1.2 times in a conveyance direction, swelling, and then immersing for 1 minute in 0.03 weight% of potassium iodide concentration of 30 degreeC, and 0.3 weight% of iodine concentration, It extended | stretched 3 times based on the film (circle length) not extending | stretching in a conveyance direction at the time of dyeing. Next, it extended | stretched 6 times based on the original length in the conveyance direction, immersing for 30 second in the aqueous solution of 4 weight% of boric acid concentration of 60 degreeC, and 5 weight% of potassium iodide concentrations. Next, the polarizer was obtained by drying the obtained stretched film at 70 degreeC for 2 minutes. In addition, the thickness of the polarizer was 30 micrometers.

In this way, through a poly vinyl alcohol-based adhesive, a modified methacrylate-based resin film (trade name Toyo plate "fine cast film RZ-30NA-S", on both surfaces of the obtained polarizer photoelastic coefficient: 1.5 × 10 ^-12 ㎡ / N) was bonded together and the polarizing plate in which the transparent protective film was laminated | stacked on the polarizer was produced.

(Production of Adhesive Polarizer)

The undercoat was apply | coated to the surface of the transparent protective film of the said polarizing plate, and the undercoat layer (thickness 100nm) was formed. Polyethyleneimine (made by Nippon Catalysts, Epomin P-1000) was used as a primer. Next, the release sheet which provided the said adhesive layer in the undercoat layer was bonded together, and it was set as the adhesive polarizing plate.

Example 2 3, Comparative Example 1? 4]

In the preparation of the pressure-sensitive adhesive of Example 1, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the injection ratio of butyl acrylate and benzyl acrylate was changed.

Example 4 6, comparative example 5? 8]

In the preparation of the pressure-sensitive adhesive of Example 1, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the injection ratio of butyl acrylate and benzyl acrylate was changed. Moreover, in preparation of the polarizing plate of Example 1, instead of using a methyl methacrylate resin film as a transparent protective film, cyclic olefin resin film (Nippon Xeon make brand name "Zenoa film ZB14-55124", a photoelastic coefficient : 4.0 × 10 ^-12 m 2 / N) was used. Others were carried out similarly to Example 1, and produced the adhesive polarizing plate.

[Example 7? 9, Comparative Example 9? 12]

In the preparation of the pressure-sensitive adhesive of Example 1, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the injection ratio of butyl acrylate and benzyl acrylate was changed. Moreover, in preparation of the polarizing plate of Example 1, instead of using a modified methyl methacrylate type resin film as a transparent protective film, a triacetyl cellulose film (Fujifilm make brand name "Fuji Tak TD80UL", photoelastic coefficient: 16x10) ^-12 m 2 / N) was used. A pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1 except for the above.

Example 10 12, Comparative Example 13? 16]

In the preparation of the pressure-sensitive adhesive of Example 1, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the injection ratio of butyl acrylate and benzyl acrylate was changed. In addition, in the preparation of the polarizing plate of Example 1, instead of using a modified methyl methacrylate-based resin film as a transparent protective film, a triacetyl cellulose film (trade name "KC4KR-1" manufactured by Konica Minolta, Photoelastic coefficient: 21.8 x 10) ^-12 m 2 / N) was used. Others were carried out similarly to Example 1, and produced the adhesive polarizing plate.

[Example 13? 15, Comparative Example 17? 20]

In the preparation of the pressure-sensitive adhesive of Example 1, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the injection ratio of butyl acrylate and benzyl acrylate was changed. Moreover, in preparation of the polarizing plate of Example 1, instead of using a modified methyl methacrylate type resin film as a transparent protective film, the phenyl maleimide type resin film (Tosoh make brand name "TI-160 (alpha)", photoelastic coefficient: -14 X10 ^-12 m 2 / N) was used. A pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1 except for the above.

[Example 16? 18, Comparative Example 21? 24]

In the preparation of the pressure-sensitive adhesive of Example 1, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the injection ratio of butyl acrylate and benzyl acrylate was changed. Moreover, in preparation of the polarizing plate of Example 1, a modified polycarbonate film (Teijin Chemical make brand name "Pure Ace WR", photoelastic coefficient: -30 instead of using a modified methyl methacrylate type resin film as a transparent protective film) X10 ^-12 m 2 / N) was used. A pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1 except for the above.

[Production of liquid crystal panel]

The liquid crystal panel was taken out from the liquid crystal television (Sony make brand name "BRAVIA") equipped with the liquid crystal cell of VA and IPS mode, the polarizing plate arrange | positioned up and down of the liquid crystal cell was removed, and the glass surface (front and back) of this liquid crystal cell was wash | cleaned. Subsequently, the adhesive type polarizing plates produced by each said Example and the comparative example were bonded to both surfaces of the said liquid crystal cell.

[evaluation]

(Measurement of Luminance in Screen Center and Screen Corners)

After the liquid crystal panel to which the adhesive type polarizing plate of each Example and the comparative example was bonded was put into a 95 degreeC air circulation thermostat for 24 hours, the liquid crystal panel was taken out, and it displayed black on the backlight of brightness 10,000 cd / m <2>, and the brightness measuring device The brightness | luminance of the front direction in the screen center part and screen corner part (four corners) was measured by (TOPCON make brand name "BM-5A").

(Measurement of In-plane Luminance Deviation)

Moreover, the liquid crystal panel before and after 24 hours of injecting into a 95 degreeC air circulation type thermostat is made black on the backlight of luminance 100 cd / m <2>, and the in-plane luminance of a screen is measured by an in-plane luminance measuring device (E.S. system brand name "EyeScale". -4 W &quot;).

The measurement result of brightness is shown in Table 1 with the composition of the adhesive of the adhesive polarizing plate of each Example and a comparative example, and the value of the photoelastic coefficient of a transparent protective film. In addition, in Table 1, X shows the photoelastic coefficient of a transparent protective film, Y shows content (weight%) of the (meth) acrylate monomer unit which has an aromatic tourism image in the acrylic polymer which comprises an adhesive. In addition, the brightness | luminance of a corner part is an average value of four corners of a screen, and a "luminance difference" shows the difference of a screen center part and a corner part. Table 1 shows a Δσ of the difference Δσ = σ -σ _{24h 0h 24h} of the deviation σ in the in-plane luminance after the high temperature test the deviation in the in-plane luminance before the input σ _0h and high temperature test input.

As shown in Table 1, in the liquid crystal display device using the pressure-sensitive adhesive polarizing plate of the example, the difference in luminance at the center of the screen and the corner portion is small, and the change in variation in in-plane luminance before and after the heating test is also suppressed. Thus, it turns out that the liquid crystal display device using the adhesive polarizing plate of this invention does not generate | occur | produce light leakage and the change of brightness | luminance by the change of a use environment.

1 polarizer
2, 3 transparent protective film
5 adhesive layer
10 Adhesive Polarizer
20 image display cells
100 image display device

Claims (3)

As an adhesive type polarizing plate in which the transparent protective film is laminated | stacked on the at least single side | surface of a polarizer, and the adhesive layer was laminated | stacked on the surface of the side which is not laminated | stacked with the polarizer of the said transparent protective film,
The pressure-sensitive adhesive layer is formed of an adhesive containing an acrylic polymer containing an alkyl (meth) acrylate and a (meth) acrylate having an aromatic ring structure as a monomer unit,
When the photoelastic coefficient of the transparent protective film is X (m 2 / N) and the content of the (meth) acrylate monomer unit having an aromatic ring structure in the acrylic polymer is Y%, the absolute value of X is 50 × 10 ^−12. A pressure-sensitive adhesive polarizing plate which is below and further satisfies -1 × 10 ¹¹ X + 3 ≦ Y ≦ -1 × 10 ¹¹ X + 23. The method of claim 1,
The adhesive polarizing plate in which the said transparent protective film contains at least 1 sort (s) of resin chosen from the group which consists of acrylic resin, cyclic olefin resin, phenyl maleimide resin, cellulose resin, and modified polycarbonate resin. The image display apparatus in which the adhesive polarizing plate of Claim 1 or 2 is used.

Images