KR20210000755A - Adhesive layer-equipped polarization film, and image display device - Google Patents

Abstract

It is an object of the present invention to provide a polarizing film having a pressure-sensitive adhesive layer that can solve the problem of yield reduction and can provide a sufficient ultraviolet-cutting function even when the polarizing film is thin. In addition, it is another object of the present invention to provide an image display device using a polarizing film having the pressure-sensitive adhesive layer. In an image display device, it is a polarizing film having a pressure-sensitive adhesive layer, which is used on the viewer side rather than an image display part, and the polarizing film having the pressure-sensitive adhesive layer has a polarizing film and a pressure-sensitive adhesive layer on both sides of the polarizing film, and the polarizing film is a polarizer and It has a transparent protective film on both surfaces of the said polarizer, and the transmittance|permeability in wavelength 380nm of the transparent protective film on the viewing side of the said polarizer is 6% or more, and the adhesive layer on the viewing side of the said polarizing film has an ultraviolet absorption function. It is a polarizing film having an adhesive layer characterized by having.

Description

A polarizing film having an adhesive layer, and an image display device {ADHESIVE LAYER-EQUIPPED POLARIZATION FILM, AND IMAGE DISPLAY DEVICE}

The present invention relates to a polarizing film having an adhesive layer used for an image display device. Further, the present invention relates to an image display device using the polarizing film having the pressure-sensitive adhesive layer. Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a plasma display panel (PDP), and electronic paper.

For the liquid crystal display device, the organic EL display device, and the like, from the image forming method thereof, for example, in a liquid crystal display device, it is necessary to arrange polarizing elements on both sides of a liquid crystal cell, and generally, a polarizing film is adhered thereto. In addition, in addition to polarizing films, various optical elements have been used in display panels such as liquid crystal panels and organic EL panels to improve display quality of the display.

Polarizing films used in these image display devices generally have a configuration in which a polarizer is sandwiched between two protective films, and triacetyl cellulose (TAC) is widely used as a protective film.

In recent years, with the flow of lightening and thinning of the image display device, thinning is required for each member used in the image display device, and thinning is also required for the protective film of the polarizing film. When the thickness of the protective film becomes thin, ultraviolet rays incident on the image display device cannot be sufficiently cut, so that not only the polarizer, but also various optical members including liquid crystal panels and organic EL elements used in image display devices, are deteriorated by ultraviolet rays. There were problems such as speeding up.

In order to solve such a problem, for example, it is a double-sided adhesive sheet for integrating two members by placing it between the surface protection panel in the image display device and the viewing side of the liquid crystal module, and having at least one ultraviolet absorbing layer. , A transparent double-sided adhesive sheet for an image display device (for example, see Patent Document 1) having a light transmittance of 30% or less at a wavelength of 380 nm and a visible light transmittance of 80% or more on the longer wavelength side than the wavelength of 430 nm, or an acrylic polymer And a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing a triazine-based ultraviolet absorber is known (see, for example, Patent Document 2). In addition, in an adhesive optical film in which an adhesive layer is provided on one or both surfaces of an optical film, it is known that an ultraviolet absorbing ability can be imparted to the adhesive layer (see, for example, Patent Document 3).

Japanese Patent Publication No. 2012-211305 Japanese Patent Publication No. 2013-75978 Japanese Patent No. 4208187 Publication

In recent years, as described in Patent Documents 1 to 3, it is known to bond various members used in image display devices using a transparent adhesive having an ultraviolet absorbing function, but in this case, thickness unevenness or yield deterioration There was a problem in terms of workability, etc.

Therefore, it is an object of the present invention to provide a polarizing film having a pressure-sensitive adhesive layer that can solve the problem of lowering the yield and can provide a sufficient ultraviolet-cutting function even when the polarizing film is thin. In addition, it is another object of the present invention to provide an image display device using a polarizing film having the pressure-sensitive adhesive layer.

The inventors of the present invention repeated intensive examinations in order to solve the above problems, and as a result, found out a polarizing film having the following pressure-sensitive adhesive layer to complete the present invention.

That is, the present invention is a polarizing film having a pressure-sensitive adhesive layer, which is used on the viewer side rather than the image display portion in an image display device,

The polarizing film having the pressure-sensitive adhesive layer has a polarizing film and an adhesive layer on both sides of the polarizing film,

The polarizing film has a polarizer and a transparent protective film on both sides of the polarizer,

The transmittance of the transparent protective film on the visible side of the polarizer at a wavelength of 380 nm is 6% or more, and

It relates to a polarizing film having a pressure-sensitive adhesive layer, characterized in that the pressure-sensitive adhesive layer on the visible side of the polarizing film has an ultraviolet absorption function.

The transparent protective film on the visible side of the polarizer is at least one film selected from the group consisting of a triacetyl cellulose film, an acrylic film, a polyethylene terephthalate film, and a polyolefin film having a cyclo-based or norbornene structure, and It is preferable that the thickness is 40 μm or less.

It is preferable that the thickness of the pressure-sensitive adhesive layer on the viewing side of the polarizing film is at least twice the thickness of the pressure-sensitive adhesive layer on the image display portion side of the polarizing film.

It is preferable that the transmittance at a wavelength of 380 nm is 40% or less, and the transmittance at a wavelength of 400 nm is 30% or more in the pressure-sensitive adhesive layer on the visible side of the polarizing film.

It is preferable that the b* value of the pressure-sensitive adhesive layer on the visible side of the polarizing film is 3.0 or less.

It is preferable that the pressure-sensitive adhesive layer on the visible side of the polarizing film contains an acrylic polymer as a base polymer.

It is preferable to use the polarizing film which has an adhesive layer of this invention for a liquid crystal display device or an organic EL display device.

Further, the present invention relates to an image display device characterized in that the polarizing film having the pressure-sensitive adhesive layer is used on the visual side rather than the image display unit.

Since the polarizing film having the pressure-sensitive adhesive layer of the present invention has a configuration in which the pressure-sensitive adhesive layer having an ultraviolet absorbing function is previously laminated on the viewing side of the polarizing film, it is possible to solve the problems of process reduction and yield reduction, and the polarizing film is thin. Even in the case, a sufficient ultraviolet ray cutting function can be provided. In addition, since the image display device of the present invention uses the polarizing film having the pressure-sensitive adhesive layer, deterioration due to ultraviolet rays of various optical members including liquid crystal panels and organic EL elements used in the image display device can be suppressed. have.

1 is a cross-sectional view schematically showing an embodiment of a polarizing film having an adhesive layer of the present invention.
2 is a cross-sectional view schematically showing an embodiment of the image display device of the present invention.
3 is a cross-sectional view schematically showing an embodiment of the image display device of the present invention.
4 is a cross-sectional view schematically showing an embodiment of the image display device of the present invention.

1. Polarizing film having an adhesive layer

The polarizing film having the pressure-sensitive adhesive layer of the present invention is used on the viewer side rather than the image display portion in an image display device,

The polarizing film having the pressure-sensitive adhesive layer has a polarizing film and an adhesive layer on both sides of the polarizing film,

The polarizing film has a polarizer and a transparent protective film on both sides of the polarizer,

The transmittance of the transparent protective film on the visible side of the polarizer at a wavelength of 380 nm is 6% or more, and

It is characterized in that the pressure-sensitive adhesive layer on the viewing side of the polarizing film has an ultraviolet absorption function.

As shown in Fig. 1, the polarizing film 1 having the pressure-sensitive adhesive layer of the present invention is a view-side pressure-sensitive adhesive layer 2a/view-side transparent protective film 3a/polarizer 4/image display part-side transparent protective film (3b)/The structure including the pressure-sensitive adhesive layer 2b on the image display part side may be sufficient, and the structure including a retardation film or the like may be used. Specifically, the view-side adhesive layer (2a)/view-side transparent protective film (3a)/polarizer (4)/image display-side transparent protective film (3b)/image-display-side pressure-sensitive adhesive layer (2b)/phase difference film (not shown) )/Image display portion side pressure-sensitive adhesive layer (not shown) or the like. The polarizing film 5 is comprised of the visible side transparent protective film 3a/polarizer 4/image display part side transparent protective film 3b. Each layer will be described in detail below.

(1) Visual side adhesive layer

In the present invention, it is characterized in that the pressure-sensitive adhesive layer (view-side pressure-sensitive adhesive layer) of the polarizing film has an ultraviolet absorption function. The visual-side pressure-sensitive adhesive layer may have an ultraviolet absorption function, and its composition is not particularly limited.

A suitable pressure-sensitive adhesive may be used to form the visual-side pressure-sensitive adhesive layer, and there is no particular limitation on the kind. Examples of the adhesive include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinylalkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used in that they are excellent in optical transparency, show moderate adhesiveness, cohesiveness and adhesive properties, and are excellent in weather resistance and heat resistance. The acrylic pressure-sensitive adhesive contains an acrylic polymer as a base polymer.

The visibility side pressure-sensitive adhesive layer using the acrylic pressure-sensitive adhesive is, for example, a monomer component containing an alkyl (meth) acrylate and/or a partial polymer of the monomer component, an ultraviolet absorber, and a photopolymerization initiator having an absorption band at a wavelength of 400 nm or more ( It is preferably formed by ultraviolet polymerization of the ultraviolet curable acrylic pressure-sensitive adhesive composition containing A). The pressure-sensitive adhesive layer formed by UV polymerization of the ultraviolet-curable acrylic pressure-sensitive adhesive composition is preferable because it is possible to form a pressure-sensitive adhesive layer having a thickness of 150 μm or more, and thus a pressure-sensitive adhesive layer having a wide thickness can be formed.

Examples of the alkyl (meth)acrylate include those having a linear or branched alkyl group having 1 to 24 carbon atoms at the ester terminal. Alkyl (meth) acrylate may be used alone or in combination of two or more. In addition, alkyl (meth)acrylate refers to an alkyl acrylate and/or an alkyl methacrylate, and has the same meaning as the (meth) of the present invention.

As the alkyl (meth)acrylate, for example, an alkyl (meth)acrylate having a branch having 4 to 9 carbon atoms can be exemplified. The said alkyl (meth)acrylate is preferable from the point that it is easy to balance adhesive property. Specifically, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl ( Meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, and the like. And these may be used alone or in combination of two or more.

In the present invention, the alkyl (meth)acrylate having an alkyl group having 1 to 24 carbon atoms at the ester terminal is preferably 40% by weight or more with respect to the total amount of the monofunctional monomer component forming the (meth)acrylic polymer, and 50 It is more preferably at least 60% by weight, even more preferably at least 60% by weight.

As the monomer component, as a monofunctional monomer component, a copolymerization monomer other than the alkyl (meth)acrylate can be contained. The copolymerized monomer can be used as the remainder of the alkyl (meth)acrylate in the monomer component.

As a copolymerization monomer, a cyclic nitrogen-containing monomer can be contained, for example. As the cyclic nitrogen-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group, and having a cyclic nitrogen structure can be used without particular limitation. It is preferable that the cyclic nitrogen structure has a nitrogen atom in the cyclic structure. Examples of the cyclic nitrogen-containing monomer include lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; Vinyl-based monomers having a nitrogen-containing heterocycle, such as vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine. . Further, a (meth)acrylic monomer containing a heterocycle such as a morpholine ring, a piperidine ring, a pyrrolidine ring, and a piperazine ring may be mentioned. Specifically, N-acryloylmorpholine, N-acryloyl piperidine, N-methacryloyl piperidine, N-acryloylpyrrolidine, and the like can be mentioned. Among the cyclic nitrogen-containing monomers, lactam-based vinyl monomers are preferred.

In the present invention, the cyclic nitrogen-containing monomer is preferably 0.5 to 50% by weight, more preferably 0.5 to 40% by weight, and 0.5 to 30% by weight based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer. The weight percent is more preferred.

The monomer component used in the present invention may contain a hydroxyl group-containing monomer as a monofunctional monomer component. As the hydroxyl group-containing monomer, one having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group, and having a hydroxyl group can be used without particular limitation. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate. )Acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12- Hydroxyalkyl (meth)acrylates such as hydroxylauryl (meth)acrylate; Hydroxyalkylcycloalkane (meth)acrylates, such as (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, are mentioned. In addition, hydroxyethyl (meth)acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like may be mentioned. These can be used alone or in combination. Among these, hydroxyalkyl (meth)acrylate is suitable.

In the present invention, the hydroxyl group-containing monomer is preferably 1% by weight or more, and more preferably 2% by weight or more from the viewpoint of enhancing adhesion and cohesion with respect to the total amount of the monofunctional monomer component forming the (meth)acrylic polymer. It is preferable, and it is more preferable that it is 3 weight% or more. On the other hand, when the amount of the hydroxyl group-containing monomer is too large, the adhesive layer may become hard and the adhesive strength may decrease, and the viscosity of the pressure-sensitive adhesive may be too high or gelatinized. Therefore, the hydroxyl group-containing monomer, It is preferably 30% by weight or less, more preferably 27% by weight or less, and even more preferably 25% by weight or less with respect to the total amount of the monofunctional monomer component forming the (meth)acrylic polymer.

Further, as the monomer component forming the (meth)acrylic polymer, other functional group-containing monomers can be contained as a monofunctional monomer, and examples thereof include a carboxyl group-containing monomer and a monomer having a cyclic ether group.

As the carboxyl group-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group, and having a carboxyl group can be used without particular limitation. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like. It can be used alone or in combination. As for itaconic acid and maleic acid, these anhydrides can be used. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable. Further, as the monomer component used in the production of the (meth)acrylic polymer of the present invention, a carboxyl group-containing monomer may be optionally used, and on the other hand, a carboxyl group-containing monomer may not be used.

As the monomer having a cyclic ether group, those having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group, and having a cyclic ether group such as an epoxy group or an oxetane group can be used without particular limitation. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether. . Examples of the oxetane group-containing monomer include 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate, 3-butyl-oxetanylmethyl (meth)acrylate, 3-hexyl-oxetanylmethyl (meth)acrylate, etc. are mentioned. These can be used alone or in combination.

In the present invention, the carboxyl group-containing monomer and the monomer having a cyclic ether group are preferably 30% by weight or less, more preferably 27% by weight or less, based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer, It is more preferably 25% by weight or less.

As the monomer component forming the (meth)acrylic polymer of the present invention, as a copolymerization monomer, for example, CH ₂ =C(R ¹ )COOR ² (wherein R ¹ is hydrogen or a methyl group, R ² is a C 1 to C 3 Alkyl (meth)acrylate represented by a substituted alkyl group and a cyclic cycloalkyl group) can be mentioned.

Here, the substituent of the substituted alkyl group having 1 to 3 carbon atoms as R ² is preferably an aryl group having 3 to 8 carbon atoms or an aryloxy group having 3 to 8 carbon atoms. Although it is not limited as an aryl group, a phenyl group is preferable.

Examples of such a monomer represented by CH ₂ =C(R ¹ )COOR ² include phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, 3,3,5-trimethylcyclo Hexyl (meth)acrylate, isobornyl (meth)acrylate, etc. are mentioned. These can be used alone or in combination.

In the present invention, the (meth)acrylate represented by CH ₂ =C(R ¹ )COOR ² may be used in an amount of 50% by weight or less based on the total amount of the monofunctional monomer component forming the (meth)acrylic polymer, , 45% by weight or less is preferable, 40% by weight or less is more preferable, and 35% by weight or less is still more preferable.

Examples of other copolymerization monomers include vinyl acetate, vinyl propionate, styrene, and α-methylstyrene; Glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; Acrylic acid ester monomers such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and 2-methoxyethylacrylate; An amide group-containing monomer, an amino group-containing monomer, an imide group-containing monomer, N-acryloylmorpholine, a vinyl ether monomer, and the like can also be used. Further, as the copolymerization monomer, a monomer having a cyclic structure such as terpene (meth)acrylate and dicyclopentanyl (meth)acrylate can be used.

Moreover, a silane-based monomer containing a silicon atom, etc. are mentioned. As a silane-based monomer, for example, 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8- Vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltri Ethoxysilane, 10-acryloyloxydecyl triethoxysilane, etc. are mentioned.

As the monomer component forming the (meth)acrylic polymer of the present invention, in addition to the monofunctional monomer of the above example, a polyfunctional monomer may be contained as necessary in order to adjust the cohesive strength of the pressure-sensitive adhesive.

The polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group, for example (poly)ethylene glycol di(meth)acrylate, (poly) Propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, 1,12-dodecanedioldi(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetra Ester compounds of polyhydric alcohol and (meth)acrylic acid, such as methylolmethane tri(meth)acrylate; Allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di (meth) acrylate, hexyl di (meth) acrylate, and the like. have. Among these, trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be suitably used. The polyfunctional monomer may be used alone or in combination of two or more.

The amount of the polyfunctional monomer to be used varies depending on the molecular weight or the number of functional groups, but it is preferably used in an amount of 3 parts by weight or less, more preferably 2 parts by weight or less, and 1 part by weight or less, based on 100 parts by weight of the total of the monofunctional monomer. Is more preferred. Moreover, although it does not specifically limit as a lower limit, It is preferable that it is 0 weight part or more, and it is more preferable that it is 0.001 weight part or more. When the amount of the polyfunctional monomer used is within the above range, adhesion can be improved.

In the present invention, a partial polymerization product of the monomer component may be used.

Although it does not specifically limit as the ultraviolet absorber contained in the said ultraviolet curable acrylic adhesive composition, For example, a triazine ultraviolet absorber, a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, an oxybenzophenone ultraviolet absorber, a salicylic acid ester ultraviolet absorber, Cyanoacrylate-based ultraviolet absorbers, and the like, and these may be used alone or in combination of two or more. Among these, a triazine-based ultraviolet absorber and a benzotriazole-based ultraviolet absorber are preferable, and a triazine-based ultraviolet absorber having two or less hydroxyl groups in one molecule, and a benzotriazole-based ultraviolet absorber having one benzotriazole skeleton in one molecule. At least one type of ultraviolet absorber selected from the group consisting of is preferable because it has good solubility in a monomer used for forming an ultraviolet curable acrylic pressure-sensitive adhesive composition, and also has a high ultraviolet absorption ability in the vicinity of a wavelength of 380 nm.

As a triazine-based ultraviolet absorber having two or less hydroxyl groups in one molecule, specifically, 2,4-bis-[{4-(4-ethylhexyloxy)-4-hydroxy}-phenyl]-6- (4-methoxyphenyl)-1,3,5-triazine (manufactured by Tinosorb S, BASF), 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibu Toxoxyphenyl)-1,3,5-triazine (TINUVIN 460, manufactured by BASF), 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl) Reaction product of -5-hydroxyphenyl and [(C10-C16 (mainly C12-C13) alkyloxy)methyl] oxirane (TINUVIN 400, manufactured by BASF), 2-[4,6-bis(2,4-dimethyl Phenyl)-1,3,5-triazine-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol, 2-(2,4-dihydroxyphenyl)- Reaction product of 4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester (TINUVIN 405, manufactured by BASF), 2-(4, 6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol (TINUVIN 1577, manufactured by BASF), 2-(4,6-diphenyl-1,3 ,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (ADK STAB LA46, manufactured by ADEKA), 2-(2-hydroxy-4-[1) -Octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (TINUVIN 479, manufactured by BASF), and the like.

In addition, as a benzotriazole-based ultraviolet absorber having one benzotriazole skeleton in one molecule, 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1, 1,3,3-tetramethylbutyl)phenol (TINUVIN 928, manufactured by BASF), 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (TINUVIN PS, manufactured by BASF), benzenepropane Acid and ester compounds of 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy(C7-9 branched and straight chain alkyl) (TINUVIN 384-2, BASF Preparation), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (TINUVIN 900, manufactured by BASF), 2-(2H-benzotriazole- 2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (TINUVIN 928, manufactured by BASF), methyl-3-(3-( Reaction product of 2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate/polyethylene glycol 300 (TINUVIN 1130, manufactured by BASF), 2-(2H-benzotriazole- 2-yl)-p-cresol (TINUVIN P, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol (TINUVIN 234, BASF), 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (TINUVIN 326, manufactured by BASF), 2-(2H-benzotria Zol-2-yl)-4,6-di-tert-pentylphenol (TINUVIN 328, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3- Tetramethylbutyl)phenol (TINUVIN 329, manufactured by BASF), methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate and polyethylene glycol 300 Reaction product of (TINUVIN 213, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (TINUVIN 571, manufactured by BASF), 2-[2-hydroxy- 3-(3,4,5,6-tetrahydrophthalimidemethyl)-5-methylfe Neil]benzotriazole (Sumisorb 250, manufactured by Sumitomo Chemical Industries, Ltd.), etc. are mentioned.

Further, examples of the benzophenone-based ultraviolet absorber (benzophenone-based compound) and oxybenzophenone-based ultraviolet absorber (oxybenzophenone-based compound) include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-me. Toxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone , 4-benzyloxy-2-hydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4-dimethoxybenzophenone, and the like. have.

In addition, as the salicylic acid ester ultraviolet absorber (salicylic acid ester compound), for example, phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, phenyl-2-acrylo Yloxy-4-methylbenzoate, phenyl-2-acryloyloxy-5-methylbenzoate, phenyl-2-acryloyloxy-3-methoxybenzoate, phenyl-2-hydroxybenzoate, phenyl -2-hydroxy-3-methylbenzoate, phenyl-2-hydroxy-4methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl2-hydroxy-3-methoxybenzoate, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (TINUVIN 120, manufactured by BASF), and the like.

As the cyanoacrylate ultraviolet absorber (cyanoacrylate compound), for example, alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, Alkenyl-2-cyanoacrylate, alkynyl-2-cyanoacrylate, etc. are mentioned.

The ultraviolet absorber may be used alone or in combination of two or more, but the content as a whole is 0.1 to 5 parts by weight based on 100 parts by weight of the monofunctional monomer component forming the (meth)acrylic polymer. It is preferable, and it is more preferably about 0.5 to 3 parts by weight. By setting the amount of the ultraviolet absorber to be in the above range, it is preferable because the adhesive layer can sufficiently exhibit the ultraviolet absorbing function and does not interfere with ultraviolet polymerization.

It is preferable that the ultraviolet-curable acrylic pressure-sensitive adhesive composition used in the present invention contains a photoinitiator (A) having an absorption band at a wavelength of 400 nm or more. In the case of including an ultraviolet absorber in the pressure-sensitive adhesive composition, when ultraviolet polymerization was performed, ultraviolet rays were absorbed by the ultraviolet absorber, and thus sufficient polymerization was not possible. However, since the ultraviolet-curable acrylic pressure-sensitive adhesive composition used in the present invention has a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more, it can sufficiently polymerize even though it contains an ultraviolet absorber.

As a photoinitiator (A) having an absorption band at a wavelength of 400 nm or more, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819, manufactured by BASF), 2,4,6-trimethylbenzoyl-diphenyl- Phosphine oxide (LUCIRIN TPO, manufactured by BASF), and the like.

The photoinitiator (A) having an absorption band at a wavelength of 400 nm or more may be used alone or in combination of two or more.

In addition, the amount of the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is not particularly limited, but is preferably less than the amount of the ultraviolet absorber, and 100 parts by weight of a monofunctional monomer component forming a (meth)acrylic polymer It is preferably about 0.005 to 1 part by weight, more preferably about 0.02 to 0.5 parts by weight. When the amount of the photoinitiator (A) added is within the above range, ultraviolet polymerization can sufficiently proceed, which is preferable.

In addition, the ultraviolet-curable acrylic pressure-sensitive adhesive composition used in the present invention can contain a photopolymerization initiator (B) having an absorption band in a wavelength of less than 400 nm. Moreover, it is preferable that the photoinitiator (B) does not have an absorption band at a wavelength of 400 nm or more. As the photoinitiator (B), photopolymerization is initiated by generating a radical by ultraviolet rays, and it is not particularly limited as long as it has an absorption band at a wavelength of less than 400 nm, and all commonly used photoinitiators can be suitably used. For example, benzoin ether photoinitiator, acetophenone photoinitiator, α-ketol photoinitiator, photoactive oxime photoinitiator, benzoin photoinitiator, benzyl photoinitiator, benzophenone photoinitiator, ketal photoinitiator , Thioxanthone-based photoinitiators, acylphosphine oxide-based photoinitiators, and the like can be used.

Specifically, as a benzoin ether-based photoinitiator, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1 , 2-diphenylethan-1-one, anisole methyl ether, and the like.

As an acetophenone-based photoinitiator, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, 4 -t-butyldichloroacetophenone, etc. are mentioned.

As an α-ketol type photoinitiator, for example, 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-hydroxy-2-methylpropane-1- On and so on.

As a photoactive oxime type photoinitiator, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime, etc. are mentioned, for example.

As a benzoin type photoinitiator, benzoin etc. are mentioned, for example.

As a benzyl type photoinitiator, benzyl etc. are contained, for example.

Examples of the benzophenone-based photoinitiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinyl benzophenone, α-hydroxycyclohexylphenyl ketone, and the like.

Benzyl dimethyl ketal etc. are contained in a ketal type photoinitiator.

Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chloro thioxanthone, 2-methyl thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone, and 2,4-dichloroti Oxanthone, 2,4-diethyl thioxanthone, 2,4-diisopropyl thioxanthone, dodecyl thioxanthone, and the like are included.

Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like.

The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm may be used alone or in combination of two or more. The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be added within a range that does not impair the effects of the present invention, but the added amount is 100 parts by weight of the monofunctional monomer component forming the (meth)acrylic polymer. It is preferably about 0.005 to 0.5 parts by weight, more preferably about 0.02 to 0.1 parts by weight.

In the present invention, in the partial polymer (prepolymer composition) of the monomer component partially polymerized by first adding a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm to the monomer component and irradiating with ultraviolet rays, the wavelength 400 nm or more It is preferable to add a photoinitiator (A) having an absorption band and an ultraviolet absorber to the ultraviolet ray absorber to perform ultraviolet polymerization. When adding the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more to the partial polymer (prepolymer composition) of the monomer component partially polymerized by UV irradiation, it is preferable to add the photopolymerization initiator after dissolving the photopolymerization initiator in the monomer. Do.

Further, the ultraviolet curable acrylic pressure-sensitive adhesive composition used in the present invention may contain a silane coupling agent. The blending amount of the silane coupling agent is preferably 1 part by weight or less, more preferably 0.01 to 1 part by weight, and even more preferably 0.02 to 0.6 parts by weight based on 100 parts by weight of the monofunctional monomer component forming the (meth)acrylic polymer.

As the silane coupling agent, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4 epoxycyclo Epoxy group-containing silane coupling agent such as hexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N -(1,3-dimethylbutylidene)propylamine, amino group-containing silane coupling agent such as N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyl (Meth)acrylic group-containing silane coupling agents such as triethoxysilane, and isocyanate group-containing silane coupling agents such as 3-isocyanate propyltriethoxysilane.

The ultraviolet-curable acrylic pressure-sensitive adhesive composition used in the present invention may contain a crosslinking agent. Examples of the crosslinking agent include crosslinking agents such as isocyanate crosslinking agents, epoxy crosslinking agents, silicone crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, silane crosslinking agents, alkyl ether melamine crosslinking agents, metal chelate crosslinking agents, and peroxides. One type of crosslinking agent may be used alone, or two or more types may be combined. Among these, an isocyanate crosslinking agent is preferably used.

The crosslinking agent may be used alone or in combination of two or more, but the content as a whole is 5 parts by weight or less based on 100 parts by weight of the monofunctional monomer component forming the (meth)acrylic polymer. Preferably, it is more preferably 0.01 to 5 parts by weight, more preferably 0.01 to 4 parts by weight, and particularly preferably 0.02 to 3 parts by weight.

An isocyanate-based crosslinking agent refers to a compound having two or more isocyanate groups (including an isocyanate regenerated functional group temporarily protected by a blocking agent or quantification of an isocyanate group) in one molecule. Examples of the isocyanate crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, and alicyclic isocyanates such as isophorone diisocyanate, 2,4- Aromatic diisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenyl isocyanate, trimethylolpropane/tolylene diisocyanate trimer adduct (trade name: Coronate L, Nippon Polyurethane Co., Ltd.), trimethylolpropane/hexamethylene diisocyanate trimer adduct (trade name: Coronate HL, Nippon Polyurethane Co., Ltd.), isocyanurate of hexamethylene diisocyanate ( Brand name: Coronate HX, isocyanate adducts such as Nippon Polyurethane Kogyo Co., Ltd.), trimethylolpropane adduct of xylylene diisocyanate (trade name: D110N, Mitsui Chemical Co., Ltd.), hexamethylene diisocyanate Trimethylolpropane adduct (trade name: D160N, manufactured by Mitsui Chemical Co., Ltd.); Polyether polyisocyanate, polyester polyisocyanate, and adducts of these and various polyols, isocyanurate bonds, biuret bonds, polyisocyanates obtained by polyfunctionalization by allophanate bonds, and the like.

In addition to the above components, the ultraviolet-curable acrylic pressure-sensitive adhesive composition used in the present invention may contain appropriate additives depending on the application. For example, tackifiers (such as rosin derivative resins, polyterpene resins, petroleum resins, oil-soluble phenol resins, etc., which are solid, semi-solid, or liquid at room temperature); Fillers such as hollow glass balloons; Plasticizer; Anti-aging agents; Antioxidants and the like.

In the present invention, it is preferable that the UV-curable acrylic pressure-sensitive adhesive composition is adjusted to a viscosity suitable for an operation of applying or the like on a substrate. Adjustment of the viscosity of the ultraviolet-curable acrylic pressure-sensitive adhesive composition is carried out, for example, by adding various polymers such as thickening additives or polyfunctional monomers, or by partially polymerizing the monomer component in the ultraviolet-curable acrylic pressure-sensitive adhesive composition. Moreover, the said partial polymerization may be performed before adding various polymers, such as a thickening additive, a polyfunctional monomer, etc., and may be performed after that. Since the viscosity of the UV-curable acrylic pressure-sensitive adhesive composition changes depending on the amount of additives, the polymerization rate in the case of partial polymerization of the monomer component in the UV-curable acrylic pressure-sensitive adhesive composition cannot be uniquely determined, but the target is about 20% or less. It is preferable, about 3-20% is more preferable, and about 5-15% is more preferable. If it exceeds 20%, the viscosity becomes excessively high, making it difficult to apply to the substrate.

The visible side pressure-sensitive adhesive layer can be formed by applying the ultraviolet-curable acrylic pressure-sensitive adhesive composition to at least one side of a substrate, and irradiating the ultraviolet-curable acrylic pressure-sensitive adhesive composition with ultraviolet rays.

It does not specifically limit as said base material, For example, various base materials, such as a release film and a transparent resin film base material, and a polarizing film mentioned later can also be used suitably as a base material. When the visible side pressure-sensitive adhesive layer is formed on a substrate other than a polarizing film, the visible side pressure-sensitive adhesive layer can be bonded to a polarizing film and transferred.

As a constituent material of the release film, for example, resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and laminates thereof Suitable thin-leaf bodies such as a sieve are mentioned, but a resin film is suitably used from the viewpoint of excellent surface smoothness.

Examples of the resin film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film. , A polyurethane film, an ethylene-vinyl acetate copolymer film, etc. are mentioned.

The thickness of the release film is usually 5 to 200 μm, preferably about 5 to 100 μm. The release film may be subjected to a release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, or the like, or an antistatic treatment such as a coating type, a paste type, or a vapor deposition type, if necessary. In particular, by appropriately performing a release treatment such as a silicone treatment, a long chain alkyl treatment, or a fluorine treatment on the surface of the release film, the release property from the pressure-sensitive adhesive layer can be further improved.

Although it does not specifically limit as said transparent resin film base material, Various resin films which have transparency are used. The resin film is formed by a single layer of film. For example, as the material, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins Resins, (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, and polyphenylene sulfide resins. Among these, polyester resins, polyimide resins and polyethersulfone resins are particularly preferred.

The thickness of the film substrate is preferably 15 to 200 µm, more preferably 25 to 188 µm.

The method of applying the ultraviolet-curable acrylic pressure-sensitive adhesive composition on the substrate is a roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain A known suitable method such as coat, lip coat, and die coater can be used, and is not particularly limited.

The irradiance of ultraviolet rays irradiated to the ultraviolet-curable acrylic pressure-sensitive adhesive composition is preferably 5 mW/cm 2 or more. When the irradiance of the ultraviolet rays is less than 5 mW/cm 2, the polymerization reaction time is prolonged, and productivity may decrease. Further, the irradiance of the ultraviolet rays is preferably 200 mW/cm 2 or less. When the irradiance of the ultraviolet ray exceeds 200 mW/cm 2, the photopolymerization initiator is rapidly consumed, so that the polymer has a low molecular weight, and in particular, the holding power at high temperature may decrease. In addition, it is preferable that the cumulative amount of ultraviolet rays is 100 mJ/cm 2 to 5000 mJ/cm 2.

The ultraviolet lamp used in the present invention is not particularly limited, but an LED lamp is preferable. Since the LED lamp is a lamp having a lower emission heat than other ultraviolet lamps, the temperature during polymerization of the pressure-sensitive adhesive layer can be suppressed. Therefore, it is possible to prevent lowering of the molecular weight of the polymer, prevent a decrease in the cohesive force of the pressure-sensitive adhesive layer, and increase the holding power at a high temperature when the pressure-sensitive adhesive sheet is formed. It is also possible to combine a plurality of ultraviolet lamps. In addition, by intermittently irradiating ultraviolet rays, it is also possible to provide a bright light to irradiate ultraviolet light and a memorization that does not irradiate ultraviolet light.

In the present invention, the final polymerization rate of the monomer component in the ultraviolet curable acrylic pressure-sensitive adhesive composition is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

In the present invention, the peak wavelength of the ultraviolet rays irradiated to the ultraviolet-curable acrylic pressure-sensitive adhesive composition is preferably in the range of 200 to 500 nm, more preferably in the range of 300 to 450 nm. When the peak wavelength of ultraviolet rays exceeds 500 nm, the photopolymerization initiator is not decomposed and the polymerization reaction may not be started. In addition, when the peak wavelength of ultraviolet rays is less than 200 nm, the polymer chain may be cut and the adhesive properties may be deteriorated.

Since the reaction is inhibited by oxygen in the air, in order to block oxygen, it is preferable to form a release film or the like on the coating layer of the acrylic pressure-sensitive adhesive composition or to perform a photopolymerization reaction in a nitrogen atmosphere. As a release film, the thing mentioned above is mentioned. Moreover, when a release film is used, the said release film can be used as it is as a separator of a polarizing film which has an adhesive layer.

From the viewpoint of securing an ultraviolet absorbing function, the thickness of the visible side pressure-sensitive adhesive layer is preferably at least twice the thickness of the pressure-sensitive adhesive layer on the image display side of the polarizing film (image display side pressure-sensitive adhesive layer) to be described later, and is 5 times or more. More preferably, it is more preferably 10 times or more. Specifically, the thickness of the visual-side pressure-sensitive adhesive layer is preferably 50 µm or more, more preferably 100 µm or more, and even more preferably 150 µm or more. The upper limit of the thickness of the visible side pressure-sensitive adhesive layer is not particularly limited, but is preferably 10 mm or less. If the thickness of the pressure-sensitive adhesive layer exceeds 10 mm, it is difficult to transmit ultraviolet rays, and polymerization of the monomer component may take time and productivity may decrease, which is not preferable.

In addition, when the ultraviolet curable acrylic pressure-sensitive adhesive composition used in the present invention contains a photopolymerization initiator (B), a monomer component containing an alkyl (meth)acrylate and the photopolymerization initiator (B) (referred to as ``pre-addition polymerization initiator'') In some cases), a composition containing ultraviolet rays is irradiated to form a partial polymer of the monomer component, and the partial polymer of the monomer component has an ultraviolet absorber, and a photoinitiator (A) having an absorption band at a wavelength of 400 nm or more (" It is preferable to add a post-added polymerization initiator") to prepare an ultraviolet-curable acrylic pressure-sensitive adhesive composition. The polymerization rate of the partial polymerized product is preferably about 20% or less, more preferably about 3 to 20%, and even more preferably about 5 to 15%. The irradiation conditions of ultraviolet rays are as described above.

As described above, in the case of forming the pressure-sensitive adhesive layer from the ultraviolet-curable acrylic pressure-sensitive adhesive composition containing the photoinitiator (B), the polymerization rate of the monomer component can be increased by polymerization in two steps as described above, and the finally produced The UV absorption function of the pressure-sensitive adhesive layer can be improved.

The gel fraction of the visibility side pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 50% or more, more preferably 75% or more, and even more preferably 85% or more. When the gel fraction of the visual-side pressure-sensitive adhesive layer is small, the cohesive strength may decrease, and when too large, the adhesive strength may decrease.

The transmittance b* value of the visual-side pressure-sensitive adhesive layer is not particularly limited, but it is preferably 3.0 or less, more preferably 1.5 or less, and even more preferably 0.5 or less. The b* value refers to a b* value (chromaticity) in an L*a*b* color system conforming to JIS Z8729, and for example, a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Co., Ltd.) It can be measured using.

The transmittance at a wavelength of 380 nm of the visual-side pressure-sensitive adhesive layer is preferably 40% or less, more preferably 20% or less, and even more preferably 8% or less. When the transmittance wavelength at a wavelength of 380 nm is within the above range, incident ultraviolet rays can be sufficiently blocked, so that deterioration of optical members including a liquid crystal panel, an organic EL element, and a polarizer can be suppressed.

The transmittance of the visual side pressure-sensitive adhesive layer at a wavelength of 400 nm is preferably 30% or more, preferably 50% or more, and more preferably 70% or more. When the transmittance wavelength at a wavelength of 400 nm is within the above range, incident visible light can be sufficiently transmitted and sufficient visibility can be ensured in an image display device, which is preferable.

(2) Pressure-sensitive adhesive layer on the image display side

The pressure-sensitive adhesive layer on the surface of the image display portion side of the polarizing film (the pressure-sensitive adhesive layer on the image display portion side) is not particularly limited, and the same material as the ultraviolet-curable acrylic pressure-sensitive adhesive composition detailed in the above-mentioned viewer-side pressure-sensitive adhesive layer may be used, and various pressure-sensitive adhesives commonly used Layers can be used.

A suitable pressure-sensitive adhesive can be used to form the pressure-sensitive adhesive layer on the surface of the image display portion, and there is no particular limitation on the kind. Examples of the adhesive include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinylalkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used in that they are excellent in optical transparency, show moderate adhesiveness, cohesiveness and adhesive properties, and are excellent in weather resistance and heat resistance.

The acrylic pressure-sensitive adhesive has an acrylic polymer having a monomer unit of an alkyl (meth)acrylate as a main skeleton as a base polymer. Examples of the (meth)acrylic acid alkyl ester constituting the main skeleton of the acrylic polymer include those similar to those used for the ultraviolet-curable acrylic pressure-sensitive adhesive composition for forming the visible side pressure-sensitive adhesive layer. Moreover, as a copolymerization monomer and its ratio, the thing similar to what is used for an ultraviolet-curable acrylic adhesive composition is mentioned.

The production of the acrylic polymer can be produced by various known methods, and radical polymerization methods such as a bulk polymerization method, a solution polymerization method, and a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo-based and peroxide-based compounds can be used. The reaction temperature is usually about 50 to 80°C, and the reaction time is 1 to 8 hours. In addition, among the above production methods, solution polymerization is preferred, and ethyl acetate, toluene, and the like are generally used as the solvent for the acrylic polymer. The solution concentration is usually about 20 to 80% by weight.

Further, the pressure-sensitive adhesive can be a pressure-sensitive adhesive composition containing a crosslinking agent. Examples of the crosslinking agent include those described above, and an isocyanate crosslinking agent is particularly preferable. The blending ratio of the acrylic polymer and the crosslinking agent is not particularly limited, but usually, it is preferably about 0.001 to 20 parts by weight of the crosslinking agent (solid content), more preferably about 0.01 to 15 parts by weight per 100 parts by weight of the acrylic polymer (solid content). .

Further, the pressure-sensitive adhesive may include a tackifier, a plasticizer, a glass fiber, glass beads, metal powder, and other inorganic powders, such as fillers, pigments, colorants, fillers, antioxidants, ultraviolet absorbers, silane coupling agents, etc., In addition, various additives may be appropriately used within a range not departing from the object of the present invention. Moreover, it is good also as a pressure-sensitive adhesive layer containing fine particles and exhibiting light diffusivity. Examples of the silane coupling agent include those described above.

The image display portion side pressure-sensitive adhesive layer is formed by applying the pressure-sensitive adhesive to various substrates such as a polarizing film or a release film, and drying. When the pressure-sensitive adhesive layer is formed on various substrates such as a release film, the pressure-sensitive adhesive layer can be bonded to a polarizing film and transferred. Examples of the method of applying the pressure-sensitive adhesive and the various substrates include those similar to the method of applying the ultraviolet-curable acrylic pressure-sensitive adhesive composition and the various substrates.

In addition, in the above coating process, the amount of applied is controlled so that the formed pressure-sensitive adhesive layer has a predetermined thickness (thickness after drying). Although the thickness of the pressure-sensitive adhesive layer on the image display portion side is not particularly limited, it is preferably 1/2 or less, preferably 1/5 or less, and preferably 1/10 or less of the thickness of the visual side pressure-sensitive adhesive layer. Specifically, the thickness of the pressure-sensitive adhesive layer on the side of the image display portion is preferably about 1 to 100 µm, more preferably about 3 to 50 µm, and even more preferably about 5 to 30 µm.

In formation of the pressure-sensitive adhesive layer on the image display portion side, drying is performed on the applied pressure-sensitive adhesive. The drying temperature and drying time are not particularly limited and are appropriately set, but are preferably 0.5 to 10 minutes at about 80 to 200°C, for example.

When the pressure-sensitive adhesive layer on the side of the image display portion is exposed, the pressure-sensitive adhesive layer may be protected with a release film until it is provided for practical use. Moreover, the said release film can be used as it is as a separator of a polarizing film with an adhesive layer, and simplification in a process surface is possible.

(3) polarizing film

The polarizing film used in the present invention has a polarizer and a transparent protective film on both sides of the polarizer, and the transmittance at a wavelength of 380 nm of the transparent protective film on the viewing side of the polarizer (viewing side transparent protective film) is 6% or more. It is characterized.

(3-1) Viewing side transparent protective film

The transmittance at a wavelength of 380 nm of the visibility-side transparent protective film used in the present invention is 6% or more, preferably 10% or more, and more preferably 15% or more. The upper limit of the transmittance at a wavelength of 380 nm is not particularly limited, but is preferably 90% or less, and more preferably 30% or less. When the transmittance of the visible-side transparent protective film at a wavelength of 380 nm is within the above range, the visible-side transparent protective film is thinned, and sufficient ultraviolet absorbing ability is achieved by combining it with the above-described visible-side pressure-sensitive adhesive layer (containing an ultraviolet absorber). It is desirable because it can be done. Even if the visibility-side transparent protective film does not have UV-absorbing ability, the UV-absorbing function can be sufficiently supplemented by the UV-absorption of the visible-side pressure-sensitive adhesive layer. Therefore, if the transmittance at the wavelength of 380 nm is 90% or less, the UV-absorbing ability is sufficient. Has. In addition, in the case where the visual side pressure-sensitive adhesive layer has a transmittance of 40% or less at a wavelength of 380 nm, it is preferable from the viewpoint of ultraviolet absorption ability that the transmittance of the visual side transparent protective film is 30% or less.

As a material for forming the visible side transparent protective film, those excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropic properties, and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene or acrylonitrile/styrene copolymers ( AS resin), and the like, and polycarbonate polymers. In addition, polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, polyolefin-based polymer such as ethylene-propylene copolymer, vinyl chloride-based polymer, amide-based polymer such as nylon or aromatic polyamide, imide-based polymer, sulfone-based Polymer, polyethersulfone polymer, polyetheretherketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy A polymer or a blend of the polymer may be mentioned as an example of a polymer forming the transparent protective film. The transparent protective film can also be formed as a resin cured layer of a thermosetting type, such as an acrylic type, a urethane type, an acrylic urethane type, an epoxy type, and a silicone type, and an ultraviolet curing type. Among these, as the visibility side transparent protective film, at least one selected from the group consisting of a triacetyl cellulose film, an acrylic film (a film using an acrylic polymer), a polyethylene terephthalate film, and a polyolefin film having a cyclo-based or norbornene structure. It is preferable that it is a film of, and a triacetyl cellulose film is more preferable.

The thickness of the visible side transparent protective film is not particularly limited, but it is preferably 40 µm or less, more preferably 35 µm or less, and still more preferably 30 µm or less. In addition, the lower limit of the thickness of the visible side transparent protective film is not particularly limited, but it is preferably 1 µm or more. When the thickness of the transparent protective film on the viewing side is within the above range, thinning of the polarizing film can be sufficiently achieved, and since the protective function of the polarizer is not impaired, it is preferable.

It is preferable that the polarizer and the viewing side protective film described later are in close contact with each other through a water-based adhesive or the like. Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based, water-based polyurethane, and water-based polyesters. In addition to the above, examples of the adhesive of the polarizer and the visible-side transparent protective film include an ultraviolet curable adhesive and an electron beam curable adhesive. The adhesive for electron beam-curable polarizing films exhibits suitable adhesiveness with respect to the above various visual-side transparent protective films. Further, the adhesive used in the present invention may contain a metal compound filler.

The surface of the visible-side transparent protective film on which the polarizer is not adhered may be subjected to a hard coat layer, antireflection treatment, anti-sticking, or treatment for the purpose of diffusion or anti-glare.

(3-2) polarizer

The polarizer is not particularly limited, and various types of polarizers can be used. As a polarizer, for example, a dichroic substance such as iodine or a dichroic dye is adsorbed to a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene/vinyl acetate copolymer-based partial saponification film. Polyene-based oriented films, such as a stretched thing, a dehydration treatment product of polyvinyl alcohol, a dehydrochloric acid treatment product of polyvinyl chloride, etc. are mentioned. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is suitable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 µm.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced by, for example, dyeing by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching to 3 to 7 times the original length. If necessary, it may be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, or zinc chloride. Also, if necessary, before dyeing, the polyvinyl alcohol-based film may be immersed in water and washed with water. By washing the polyvinyl alcohol-based film with water, it is possible to wash the surface of the polyvinyl alcohol-based film with an anti-contamination or blocking agent, and by swelling the polyvinyl alcohol-based film, there is an effect of preventing unevenness such as staining of dyeing. Stretching may be performed after dyeing with iodine, stretching while dyeing, or dyeing with iodine after stretching. It can also be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

In addition, in the present invention, a thin polarizer having a thickness of 10 μm or less can also be used. Speaking from the viewpoint of thinning, the thickness is preferably 1 to 7 µm. Since such a thin polarizer has little thickness unevenness, has excellent visibility, and has little dimensional change, it is excellent in durability, and further, it is preferable that the thickness as a polarizing film can also be reduced in thickness.

As a thin polarizer, representatively, Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, or International Publication No. 2010/100917, International Publication No. 2010/100917, or Japanese Patent No. The thin polarizing film described in the specification of 4751481 or Japanese Patent Laid-Open No. 2012-073563 can be mentioned. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) layer and a resin substrate for stretching in the state of a laminate and a step of dyeing. In this production method, even if the PVA-based resin layer is thin, it is supported by the resin substrate for stretching, so that it is possible to stretch without problems such as fracture due to stretching.

As the thin polarizing film, among the manufacturing methods including the step of stretching and dyeing in the state of a laminate, since it can be stretched at a high magnification and thus the polarization performance can be improved, International Publication No. 2010/100917 Pamphlet, International Publication No. It is preferably obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution as described in the pamphlet of Unexamined Publication No. 2010/100917 or the specification of Japanese Patent No. 4751481 or Publication No. 2012-073563, and in particular, Japanese Patent No. It is preferably obtained by a manufacturing method including a step of auxiliary air stretching before stretching in an aqueous boric acid solution as described in the specification of 4751481 or Japanese Patent Laid-Open No. 2012-073563.

(3-3) Transparent protective film on the image display side

About the image display side transparent protective film, what has been conventionally used can be used suitably. Specifically, a transparent protective film formed of a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. is preferable. For example, a polyester polymer such as polyethylene terephthalate or polyethylene naphthalate, diacetyl Cellulose polymers such as cellulose and triacetylcellulose, acrylic polymers such as polymethyl methacrylate, styrene polymers such as polystyrene or acrylonitrile-styrene copolymer (AS resin), and polycarbonate polymers. have. In addition, polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, polyolefin-based polymer such as ethylene-propylene copolymer, vinyl chloride-based polymer, amide-based polymer such as nylon or aromatic polyamide, imide-based polymer, sulfone-based Polymer, polyethersulfone polymer, polyetheretherketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy A polymer or a blend of the polymer may be mentioned as an example of a polymer forming the transparent protective film. The transparent protective film can also be formed as a resin cured layer of a thermosetting type, such as an acrylic type, a urethane type, an acrylic urethane type, an epoxy type, and a silicone type, and an ultraviolet curing type.

The thickness of the protective film on the image display portion side can be appropriately determined, but is generally about 1 to 500 µm from the viewpoints of workability such as strength and handling properties, and thin film properties.

The polarizer and the transparent protective film on the side of the image display portion are also usually in close contact with each other through a water-based adhesive or the like. Examples of the water-based adhesive include those described above.

The surface of the transparent protective film on the image display portion side to which the polarizer is not adhered may be subjected to a hard coat layer, antireflection treatment, anti-sticking, or treatment for the purpose of diffusion or anti-glare.

2. Image display device

The image display device of the present invention is characterized by using the polarizing film having the pressure-sensitive adhesive layer of the present invention.

As an example of a specific configuration of an image display device, for example, as shown in Figs. 2 to 4,

Cover glass or cover plastic (6)/view side adhesive layer (2a)/view side transparent protective film (3a)/polarizer (4)/image display side transparent protective film (3b)/image display side side adhesive layer (2b)/ A liquid crystal display (LCD) or organic EL display (OLED) 7 (Fig. 2);

Cover glass or plastic cover (6)/adhesive layer (8a)/sensor layer (9)/view-side adhesive layer (2a)/view-side transparent protective film (3a)/polarizer (4)/image display-side transparent protective film ( 3b)/image display portion side pressure-sensitive adhesive layer 2b/liquid crystal display (LCD) or organic EL display (OLED) 7 (Fig. 3);

Cover glass or plastic cover (6)/adhesive layer (8a)/sensor layer (9)/adhesive layer (8b)/sensor layer (9)/view side adhesive layer (2a)/view side transparent protective film (3a)/ Polarizer 4/image display portion side transparent protective film 3b/image display portion side pressure-sensitive adhesive layer 2b/liquid crystal display device (LCD) or organic EL display device (OLED) 7 (FIG. 4);

As described above, an image display device in which each layer is stacked in this order is exemplified. The polarizing film 1 having the pressure-sensitive adhesive layer of the present invention is ``view-side pressure-sensitive adhesive layer (2a) / view-side transparent protective film (3a) / polarizer (4) / image display portion-side transparent protective film (3b) in the above-described configuration / The image display part side pressure-sensitive adhesive layer 2b", and may contain a retardation film etc. in addition to these. In addition, in the case of including a retardation film, specifically, it may be laminated between the pressure-sensitive adhesive layer 2b on the image display portion side and the liquid crystal display device (LCD) or organic EL display device (OLED) 7 through the pressure-sensitive adhesive layer. Further, in laminating each layer, an adhesive layer and/or an adhesive layer can be appropriately used.

Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a plasma display panel (PDP), and electronic paper. Among these, a liquid crystal display device having the above-described configuration, an organic EL (electroluminescence) display device, etc. Nessense) display devices and the like are preferred.

Example

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited by these examples. In addition, both parts and% in each example are based on weight. Evaluation items in Examples and the like were measured as follows.

Preparation Example 1 (Preparation of acrylic pressure-sensitive adhesive composition (a-1))

As a photopolymerization initiator in a monomer mixture consisting of 78 parts by weight of 2-ethylhexyl acrylate (2EHA), 18 parts by weight of n-vinyl-2-pyrrolidone (NVP) and 4 parts by weight of 2-hydroxyethyl acrylate (HEA) 1- Hydroxycyclohexylphenylketone (trade name: Irgacure 184, having an absorption band in a wavelength of 200 to 370 nm, manufactured by BASF) 0.035 parts by weight, 2,2-dimethoxy-1,2-diphenylethan-1-one (Brand name: Irgacure 651, having an absorption band at a wavelength of 200 to 380 nm, manufactured by BASF) After blending 0.035 parts by weight, the viscosity (measurement condition: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30° C.) is about UV rays were irradiated to 20 Pa·s to obtain a prepolymer composition (polymerization rate: 8%) in which a part of the monomer component was polymerized. Next, 0.15 parts by weight of hexanediol diacrylate (HDDA) and 0.3 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and mixed to the prepolymer composition, and the acrylic pressure-sensitive adhesive composition ( a-1) was obtained.

Preparation Example 2 (Preparation of acrylic pressure-sensitive adhesive composition (a-2))

Butyl acrylate (BA) 67 parts by weight, cyclohexyl acrylate (CHA) 14 parts by weight, 4-hydroxybutyl acrylate (4HBA) 27 parts by weight, 2,2-dimethoxy-1,2-di as a photoinitiator Phenyl-1-one (trade name: Irgacure 651, having an absorption band at a wavelength of 200 to 380 nm, manufactured by BASF Japan) 0.05 parts by weight and 1-hydroxy-cyclohexyl-phenyl-ketone (trade name: Irgacure 184 , Having an absorption band at a wavelength of 200 to 370 nm, manufactured by BASF Japan) 0.05 parts by weight of a 4-neck flask, exposure to ultraviolet rays under a nitrogen atmosphere, and partial photopolymerization to obtain a partial polymer (monomer syrup) with a polymerization rate of 10% . Next, dipentaerythritol penta and hexaacrylate (DPHA) 0.15 parts by weight and 0.3 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the partial polymer and mixed. And ultraviolet irradiation to obtain an acrylic pressure-sensitive adhesive composition (a-2).

Production Example 3 (Production of the pressure-sensitive adhesive layer (B-1) on the image display portion side)

After adding 95 parts of butyl acrylate, 5 parts of acrylic acid, 0.2 parts of azobisisobutyronitrile, and 233 parts of ethyl acetate as a polymerization initiator into a separable flask equipped with a thermometer, agitator, a reflux condenser and a nitrogen gas introduction tube, Nitrogen substitution was performed for about 1 hour while flowing nitrogen gas and stirring. Then, the flask was heated at 60°C and reacted for 7 hours to obtain an acrylic polymer with a weight average molecular weight (Mw) of 1.1 million.

0.8 parts by weight of trimethylolpropane tolylene diisocyanate (trade name: Coronate L, manufactured by Nippon Polyurethane Kogyo Co., Ltd.) as an isocyanate crosslinking agent in the acrylic polymer solution (solid content is 100 parts by weight), silane coupling agent (trade name: KBM) 0.1 part of -403, manufactured by Shin-Etsu Chemical Co., Ltd. was added to prepare a pressure-sensitive adhesive composition (solution).

The obtained pressure-sensitive adhesive composition solution was applied onto a 38 μm-thick separator (a polyethylene terephthalate-based film whose surface was peeled off) to a thickness of 12 μm after drying, and dried at 100° C. for 3 minutes to remove the solvent to remove the adhesive layer. Got it. Then, it heated at 50 degreeC for 48 hours, and the crosslinking process was performed. Hereinafter, this adhesive layer is referred to as "the image display part side adhesive layer (B-1)".

Production Example 4 (Production of the pressure-sensitive adhesive layer (B-2) on the image display portion side)

The pressure-sensitive adhesive composition solution obtained in Preparation Example 3 was applied onto a separator having a thickness of 38 μm (a polyethylene terephthalate-based film having a release-treated surface) so that the thickness after drying was 15 μm, and dried at 100° C. for 3 minutes to remove the solvent. Removed to obtain a pressure-sensitive adhesive layer. Then, it heated at 50 degreeC for 48 hours, and the crosslinking process was performed. Hereinafter, this adhesive layer is referred to as "the image display part side adhesive layer (B-2)".

Example 1

(Preparation of an adhesive composition having an ultraviolet absorption function)

2,4-bis-[{4-(4-ethylhexyloxy)-4-hydroxy}-phenyl]- dissolved in the obtained acrylic pressure-sensitive adhesive composition (a-1) so as to have a solid content of 15% in butyl acrylate 1.4 parts of 6-(4-methoxyphenyl)-1,3,5-triazine (trade name: Tinosorb S, manufactured by BASF Japan) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide ( Trade name: Irgacure 819), having an absorption band at a wavelength of 200 to 450 nm, manufactured by BASF Japan) 0.2 part was added and stirred to obtain a pressure-sensitive adhesive composition having an ultraviolet absorption function.

The pressure-sensitive adhesive composition having an ultraviolet absorbing function was applied onto the film from which the release film was peeled off so that the thickness after the pressure-sensitive adhesive layer was formed was 150 μm, and the release film was then bonded to the surface of the pressure-sensitive adhesive composition layer. Thereafter, UV irradiation was performed under conditions of illuminance: 6.5 mW/cm 2 and light quantity: 1500 mJ/cm 2 to photocure the pressure-sensitive adhesive composition layer to form a visible side pressure-sensitive adhesive layer (A-1).

(Preparation of polarizing film (P-1))

To the viewing side of a polarizer made of a 12 μm-thick stretched polyvinyl alcohol film impregnated with iodine, a 25 μm-thick triacetylcellulose film was bonded to the viewing side of a polarizer using a polyvinyl alcohol-based adhesive, and poly(polyvinyl alcohol) was attached to the surface of the image display portion side of the polarizer. An acrylic film having a thickness of 20 μm was laminated using a vinyl alcohol adhesive to obtain a polarizing film (P-1). The polarization degree of the polarizing film was 99.995.

(Production of a polarizing film having an adhesive layer)

The visible side pressure-sensitive adhesive layer (A-1) was laminated on the viewing side of the polarizing film (P-1) (that is, the surface of a 25 µm-thick triacetylcellulose film). An image display portion side pressure-sensitive adhesive layer (B-1) was laminated on the image display portion side surface of the polarizing film (P-1) (that is, the surface of an acrylic film having a thickness of 20 μm), and a retardation film (thickness: 56 μm, Material: polycarbonate) and the pressure-sensitive adhesive layer (B-2) on the image display portion side were laminated to form a polarizing film having a pressure-sensitive adhesive layer. The polarizing film having the obtained pressure-sensitive adhesive layer is the visible side pressure-sensitive adhesive layer (A-1)/polarizing film (P-1)/image display portion side pressure-sensitive adhesive layer (B-1)/phase difference film/image display portion side pressure-sensitive adhesive layer (B-2) ).

Examples 2 to 10

A polarizing film having a pressure-sensitive adhesive layer was formed in the same manner as in Example 1, except that the amount of the ultraviolet absorber added and the thickness after formation of the visible side pressure-sensitive adhesive layer were as described in Table 1.

Examples 11 to 13

A polarizing film having a pressure-sensitive adhesive layer was formed in the same manner as in Examples 1 to 3 except that the retardation film and the image display portion side pressure-sensitive adhesive layer (B-2) were not formed.

Comparative Examples 1 to 4

The kind of polarizing film used was as described in Table 1, and except having not formed the visible side adhesive layer, it carried out similarly to Examples 11 and 1, and the polarizing film which has an adhesive layer was formed. In addition, the polarizing film (P-2) is as follows.

(Production of polarizing film (P-2))

To the viewing side of a polarizer made of a 12 µm-thick stretched polyvinyl alcohol film impregnated with iodine, a 60 µm-thick triacetylcellulose film was bonded to the viewing side of a polarizer using a polyvinyl alcohol-based adhesive. A 40 µm-thick triacetylcellulose film was laminated using a vinyl alcohol adhesive to obtain a polarizing film (P-2). The polarization degree of the polarizing film was 99.995.

Comparative Examples 5 to 8

A polarizing film having a pressure-sensitive adhesive layer was formed in the same manner as in Examples 11 and 1, except that the type of the acrylic pressure-sensitive adhesive composition for forming the visible-side pressure-sensitive adhesive layer and the amount of the ultraviolet absorber to be added were as described in Table 1.

The following evaluation was performed about the obtained adhesive layer and the polarizing film which has an adhesive layer.

<Polymerization rate>

The release film of the visible side pressure-sensitive adhesive layer used in Examples and Comparative Examples was peeled off, and only the visible side pressure-sensitive adhesive layer was placed on a weighed aluminum dish. The weight of (aluminum chalet + visual side adhesive layer) was measured, and the weight of the adhesive layer before drying was calculated|required. After drying at 130° C. for 2 hours, after cooling at room temperature for about 20 minutes, the weight of (aluminum chalet + adhesive) was measured again, and the weight of the visible side pressure-sensitive adhesive layer after drying was calculated. The polymerization rate was calculated|required by the following calculation formula.

<gel fraction>

About 0.1 g was collected from the visible side pressure-sensitive adhesive layer used in Examples and Comparative Examples, wrapped with a porous tetrafluoroethylene sheet (trade name: NTF1122, manufactured by Nitto Denko Co., Ltd.) with an average pore diameter of 0.2 μm, then tied with a twisted thread. The weight of was measured (Zg), and the weight was taken as the weight before immersion. In addition, the weight before immersion is the total weight of the visible side adhesive layer (the adhesive layer collected above), the tetrafluoroethylene sheet, and the yarn. Further, the total weight of the tetrafluoroethylene sheet and the yarn was also measured (Yg). Next, the visual-side pressure-sensitive adhesive layer was wrapped with a tetrafluoroethylene sheet and tied with a strand (referred to as "sample"), placed in a 50 mL container filled with ethyl acetate, and allowed to stand at 23°C for 7 days. Thereafter, a sample (after ethyl acetate treatment) was taken out of the container, transferred to an aluminum cup, dried at 130° C. for 2 hours, in a dryer to remove ethyl acetate, and the weight was measured (Xg), and the weight was immersed. Then it was set as the weight. The gel fraction was calculated from the following equation.

Gel fraction (% by weight) = (X-Y)/(Z-Y) x 100

<Measurement of transmittance of the visible side adhesive layer, b* value>

The release film of the visible side pressure-sensitive adhesive layer used in Examples and Comparative Examples was peeled off, and the visible side pressure-sensitive adhesive layer was mounted on a measuring jig, and measured with a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Corporation).

<Residual stress>

A test piece was prepared by cutting a width of 30 mm and a length of 50 mm from the visible side pressure-sensitive adhesive layer used in Examples and Comparative Examples to form a cylindrical shape. This was installed at 20 mm between the chuck, and the test piece was stretched by 60 mm (300%) at a tensile speed of 200 mm/min (80 mm between the chuck after stretching). It was fixed (retained and supported) for 300 seconds at a position stretched by 60 mm, and the stress value (N) after 300 seconds was measured. The residual stress was calculated|required by the following formula.

Residual stress after 300 seconds = Stress value after 300 seconds (N)/(4 × thickness of test piece/10)

<Optical reliability>

After bonding both sides of the polarizing film having the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples with glass (brand name: S200200, thickness: 1.3 mm, size: 45 mm x 50 mm, manufactured by Matsunami Glass Kogyo Co., Ltd.), Autoclave treatment (atmospheric pressure: 0.5 MPa, temperature: 50°C) was performed for 15 minutes. In Comparative Examples 1 to 4, the pressure-sensitive adhesive layer on the image display portion side of the polarizing film or the retardation film side and the glass were bonded, and the same autoclave treatment was performed as described above. Thereafter, it was introduced under various reliability conditions below, and the transmittance was measured with an ultraviolet visible near-infrared spectrophotometer (product name: V7100, manufactured by Nippon Bunko Co., Ltd.). The amount of change in transmittance from the initial stage was determined. It evaluated according to the following evaluation criteria.

(Various reliability conditions)

(Condition 1) 85℃×500h

(Condition 2) 60℃, 95% ×500h

(Condition 3) Heat shock (HS) (-40°C to 85°C) x 300 cycles

(Condition 4) Under UV irradiation×100h, illuminance: 500W/cm2 (300 to 700 nm), environmental temperature: 60 to 65°C, environmental humidity: 50%

(Evaluation standard)

○: The amount of change in transmittance is 2.0% or less.

?: Transmittance change amount is more than 2.0% and 3.0% or less.

X: Transmittance change amount is more than 3.0%.

<Adhesive contamination, dimensional accuracy, end appearance>

The polarizing film having the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 25 mm x 30 mm with a super cutter. After that, by using an end face processing machine (manufactured by Megaro Technica Co., Ltd.), the four sides of the side surfaces of the cut piece were cut by 0.05 mm to obtain a sample. As for the adhesive contamination, the presence or absence of adhesive contamination was confirmed by visually checking the side of the sample. About the dimensional accuracy and the end appearance, it observed with an optical microscope, and evaluated by the following evaluation criteria.

(Dimension precision)

○: within ±0.3㎜

×: exceeding ±0.3mm

(End appearance)

○: When there is no stickiness at the end when touched by hand

×: When there is stickiness at the end when touched by hand

In Table 1,

P-1 is a polarizing film (P-1),

P-2 is a polarizing film (P-2),

a-1 is the acrylic pressure-sensitive adhesive composition (a-1) obtained in Production Example 1,

a-2 is the acrylic pressure-sensitive adhesive composition (a-2) obtained in Production Example 2,

B-1 is the image display portion side pressure-sensitive adhesive layer (B-1) obtained in Production Example 3,

B-2 is the image display portion side pressure-sensitive adhesive layer (B-2) obtained in Production Example 4

Show.

1: polarizing film having an adhesive layer
2a: visible side adhesive layer
2b: image display portion side pressure-sensitive adhesive layer
3a: View-side transparent protective film
3b: image display portion side transparent protective film
4: polarizer
5: polarizing film
6: cover glass or cover plastic
7: Liquid crystal display (LCD) or organic EL display (OLED)
8a, 8b: adhesive layer
9: sensor layer

Claims (7)

In an image display device, it is a polarizing film having a pressure-sensitive adhesive layer that is used on the viewer side rather than the image display unit
The polarizing film having the pressure-sensitive adhesive layer has a pressure-sensitive adhesive layer on both sides of the polarizing film and the polarizing film,
The polarizing film has a transparent protective film on both sides of the polarizer and the polarizer,
The transparent protective film on both sides is adhered to the polarizer through a water-based adhesive,
The transmittance of the transparent protective film on the visible side of the polarizer at a wavelength of 380 nm is 6% or more and 90% or less,
The pressure-sensitive adhesive layer on the viewer side of the polarizing film has an ultraviolet absorption function,
The thickness of the transparent protective film on the visible side of the polarizer is 1 μm or more and 40 μm or less,
A polarizing film having a pressure-sensitive adhesive layer, characterized in that the transparent protective film on the visible side of the polarizer is a triacetyl cellulose film. The method of claim 1,
A polarizing film having a pressure-sensitive adhesive layer, wherein the thickness of the pressure-sensitive adhesive layer on the viewing side of the polarizing film is at least twice the thickness of the pressure-sensitive adhesive layer on the image display portion side of the polarizing film. The method of claim 1,
The polarizing film having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer on the visible side of the polarizing film has a transmittance of 40% or less at a wavelength of 380 nm and a transmittance of 30% or more at a wavelength of 400 nm. The method of claim 1,
The polarizing film having a pressure-sensitive adhesive layer, characterized in that the b* value of the pressure-sensitive adhesive layer on the visible side of the polarizing film is 3.0 or less. The method of claim 1,
A polarizing film having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer on the viewing side of the polarizing film contains an acrylic polymer as a base polymer. The method of claim 1,
A polarizing film having an adhesive layer, which is used for a liquid crystal display device or an organic EL display device. An image display device, characterized in that the polarizing film having an adhesive layer according to any one of claims 1 to 6 is used on the viewing side rather than the image display unit.

Images