TW201723127A - Curable adhesive composition and polarizing plate using the same - Google Patents

Abstract

The present invention provides a curable adhesive composition containing: a radical polymerizable (meth)acrylic compound and a predetermined norbornene compound. Also provided is a polarizing plate containing: a polarizing film and a thermoplastic resin film laminated on at least one surface of the polarizing film through an adhesive layer, wherein, the adhesive layer is a cured article layer of the curable adhesive composition.

Description

Curable adhesive composition and polarizing plate using the same

The present invention relates to a curable adhesive composition for a polarizing plate and a thermoplastic resin film, and a polarizing plate using the same.

A polarizing plate widely used in an image display device or the like represented by a liquid crystal display device generally has a structure in which a thermoplastic resin film such as a protective film is laminated on one surface or both surfaces of a polarizing film. In the bonding of the polarizing film and the thermoplastic resin film, an adhesive is generally used, and an example of the adhesive is conventionally known as a radical polymerizable adhesive (for example, JP-A-2010-286737).

(previous technical literature)

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-286737

Moreover, the image display device to which the polarizing plate is applied is required to have durability in the environment in which it is placed, and further durability is required for the polarizing plate. Accordingly, an object of the present invention is to provide a curable adhesive composition and a polarized light excellent in durability using the same In the plate, the curable adhesive composition is used for a polarizing film and a thermoplastic resin film, and a polarizing plate excellent in durability can be provided.

The present invention provides a curable adhesive composition and a polarizing plate shown below.

[1] A curable adhesive composition comprising: a radically polymerizable (meth)acrylic compound; and a norbornene-based compound represented by the following formula (I); (wherein R ¹ , R ² , R ³ and R ⁴ each independently represent a H atom or a substituent comprising at least one hetero atom selected from the group consisting of an O atom and an N atom; and when R ¹ and R ³ are H atoms and When R ² and R ⁴ are the above substituents, R ² and R ⁴ may form a ring structure together with the two C atoms of the reduced norbornene ring to which they are bonded.

[2] The curable adhesive composition according to [1], wherein at least one of R ¹ , R ² , R ³ and R ⁴ is the above substituent, and the substituent comprises a group selected from -C (= At least one of the groups of O)-, -OH, and -NH ₂ .

[3] The curable adhesive composition according to [2], wherein any one or both of R ¹ , R ² , R ³ and R ⁴ are the above substituents, and the substituent is selected from the group consisting of -C(=O)-O-alkyl, -C(=O)-NH-alkyl, -C(=O)-alkyl, -C(=O)-H, -C(=O)- a group of OH, -C(=O)-NH ₂ , -OC(=O)-alkyl, -OH, -NH ₂ , -alkyl-OH, and -alkyl-NH ₂ At least one hydrogen atom of the above alkyl group and alkylene group may be substituted with a group selected from the group consisting of -OH and -NH ₂ .

[4] The curable adhesive composition according to [2], wherein the radically polymerizable (meth)acrylic compound contains (meth)acrylamide monomer, R ¹ , R ² , R ³ and R ⁴ in any one of claims 1 or 2 by the above-mentioned substituents, the substituent group selected from -C (= O) -NH- alkyl -, - NH2 and ₂ - alkylene -NH ₂ group formed by The group of the group, at least one hydrogen atom of the above alkyl group and alkylene group may be substituted with a group selected from the group consisting of -OH and -NH ₂ .

[5] The curable adhesive composition according to any one of [1] to [4] which further comprises a radical polymerization initiator.

[6] The curable adhesive composition according to any one of [1] to [5] which is used as a curable adhesive composition for a polarizing film and a thermoplastic resin film.

[7] A polarizing plate comprising: a polarizing film; and a thermoplastic resin film laminated on at least one surface of the polarizing film via an adhesive layer; wherein the adhesive layer is any one of [1] to [6] A hardened layer of a hardenable adhesive composition as described.

[8] The polarizing plate according to [7], wherein the thermoplastic resin film is selected from the group consisting of a polyester resin, a polycarbonate resin, a polyolefin resin, and (meth) propylene. A resin composed of a group of an olefinic resin and a cellulose ester resin.

According to the curable adhesive composition of the present invention, a polarizing plate excellent in durability can be provided.

10‧‧‧1st thermoplastic resin film

15‧‧‧1st adhesive layer

20‧‧‧2nd thermoplastic resin film

25‧‧‧2nd adhesive layer

30‧‧‧ polarizing film

Fig. 1 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate of the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the layer configuration of the polarizing plate of the present invention.

<Sclerosing adhesive composition>

The curable adhesive composition of the present invention is a curable adhesive composition for a thermoplastic resin film such as a polarizing film or a protective film, and includes a radical polymerizable (meth)acrylic compound and the above formula (I). The decene-based compound (hereinafter also referred to as "norbornene-based compound (I)"). The detailed description of R ¹ , R ² , R ³ and R ⁴ will be described later. By containing a norbornene-based compound (I), a polarizing film can be bonded to a thermoplastic resin film by an adhesive layer which is a cured layer of a curable adhesive composition on one surface or both surfaces of a polarizing film. In the sheet, the adhesion (adhesion force) between the polarizing film and the thermoplastic resin film is improved, and the durability of the polarizing plate can be improved. Further, since the storage elastic modulus of the above-mentioned adhesive layer at 80 ° C can be improved, the durability of the polarizing plate when placed under a high temperature condition and a low temperature condition can be improved (hereinafter also referred to as "resistant thermal shock resistance"Sex").

The curable adhesive composition of the present invention may be a curable adhesive composition which is cured by heating, or may be an active energy hardened by irradiation of active energy rays such as ultraviolet rays, visible rays, electron beams and X-rays. The line curable adhesive composition is preferably an active energy ray-curable adhesive composition, and more preferably an ultraviolet curable adhesive composition.

(1) Radical polymerizable (meth)acrylic compound

The curable adhesive composition of the present invention contains a radically polymerizable (meth)acrylic compound belonging to a monomer or oligomer which causes radical polymerization and hardening by irradiation or heating of an active energy ray, As a curable (polymerizable) compound. In the present specification, the "radical polymerizable (meth)acrylic compound" means a compound having one or more (meth)acrylonium groups in the molecule. The "(meth)acrylonitrile group" means at least one selected from the group consisting of an acryloyl group and a methacryl group. The same applies to the cases referred to as "(meth)acryloyloxy), "(meth)acrylic", and "(meth)acrylate". The curable adhesive composition may contain one or two or more kinds of radically polymerizable (meth)acrylic compounds.

The radically polymerizable (meth)acrylic compound may, for example, be a (meth) acrylate monomer having at least one (meth) acryl fluorenyloxy group in the molecule, or a (meth) acrylamide monoamine. A (meth)acrylic oligomer having at least two (meth)acrylenyloxy groups in the molecule obtained by reacting two or more kinds of functional group-containing compounds. The (meth)acrylic oligomer is preferably a (meth) acrylate oligomer having at least two (meth) acryloyloxy groups in the molecule.

The (meth) acrylate single system may, for example, be a monofunctional (meth) acrylate monomer having one (meth) acryl fluorenyloxy group in the molecule and having two (meth) acrylonitrile groups in the molecule. A bifunctional (meth) acrylate monomer having a oxy group and a polyfunctional (meth) acrylate monomer having three or more (meth) acryl decyloxy groups in the molecule.

An example of a monofunctional (meth) acrylate monomer is an alkyl (meth) acrylate. Specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. Base) n-butyl acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and the like. Further, as the monofunctional (meth) acrylate monomer, an arylalkyl (meth) acrylate such as benzyl (meth) acrylate; an isodecyl (meth) acrylate or the like may also be used. a (meth) acrylate of an alcohol; a (meth) acrylate having a tetrahydrofurfuryl structure such as tetrahydrofuran methyl (meth) acrylate; a cyclohexyl (meth) acrylate or a (meth) acrylate Cyclohexylmethyl ester, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and 1,4-cyclohexanedimethanol mono(meth)acrylate have a ring at the alkyl moiety a (meth) acrylate of an alkyl group; an aminoalkyl (meth) acrylate such as N,N-dimethylaminoethyl (meth)acrylate; such as 2-phenoxyethyl (meth)acrylate Ester, dicyclopentenyloxyethyl (meth)acrylate, ethyl carbitol (meth) acrylate, and phenoxy polyethylene glycol (meth) acrylate have an ether bond at the alkyl moiety (meth) acrylate.

Further, a monofunctional alkyl (meth) acrylate having a hydroxyl group at an alkyl group and a monofunctional group having a carboxyl group at an alkyl moiety may also be used. Alkyl (meth) acrylate. Specific examples of the monofunctional alkyl (meth) acrylate having a hydroxyl group at the alkyl moiety include 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, (A) 4-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, neopentyl alcohol mono (meth) acrylate . Specific examples of the monofunctional alkyl (meth) acrylate having a carboxyl group at the alkyl moiety include 2-carboxyethyl (meth)acrylate and ω-carboxy-polycaprolactone (n≒2) mono (A) Acrylate, 1-[2-(methyl)propenyloxyethyl]phthalate, 1-[2-(methyl)propenyloxyethyl hexahydrophthalate ] ester, 1-[2-(methyl)propenyloxyethyl] succinate, 4-[2-(methyl)propenyloxyethyl]-p-triester, N- (Meth)acryloyloxy-N',N'-dicarboxymethyl-p-phenylenediamine.

The bifunctional (meth) acrylate single system may, for example, be an alkanediol di(meth)acrylate, a polyoxyalkylene glycol di(meth)acrylate, or a halogen-substituted alkanediol di(methyl). Acrylate, di(meth) acrylate of aliphatic polyol, di(meth) acrylate of dicyclopentadiene or tricyclodecane dialkyl alcohol, dioxane diol or dioxane dialkyl alcohol Di(meth) acrylate of bis(meth) acrylate, bisphenol A or bisphenol F alkylene oxide adduct, bisphenol A or bisphenol F epoxy bis (A) Base) acrylate and the like.

More specific examples of the bifunctional (meth) acrylate monomer include, for example, ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, and 1,4-butylene. Diol (meth) acrylate, 1,6-hexanediol di(meth) acrylate, 1,9-nonanediol di(meth) acrylate, neopentyl glycol di(a) Acrylate, trimethylolpropane di(meth)acrylate, neopentyl alcohol di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, diethylene glycol di( Methyl) acrylate, triethylene glycol di(meth) acrylate, dipropylene glycol di(meth) acrylate, tripropylene glycol di(meth) acrylate, polyethylene glycol di(meth) acrylate, Poly(propylene glycol) di(meth)acrylate, polybutylene glycol di(meth)acrylate, polydecane di(meth)acrylate, hydroxytrimethylacetate neopentyl glycol di(meth)acrylic acid Ester, 2,2-bis[4-(methyl)propenyloxyethoxyethoxyphenyl]propane, 2,2-bis[4-(methyl)acryloxyethoxyethoxy Oxycyclohexyl]propane, hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, 1,3-dioxane-2,5-diyl (Meth)acrylate [alias: dioxanediol di(meth)acrylate], acetal trimethylacetaldehyde and trimethylolpropane acetal compound [Chemical name: 2-(2-hydroxy-) Two of 1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane] (Meth) acrylate, tris(hydroxyethyl) trimer isocyanate di(meth)acrylate, and the like.

Examples of the trifunctional or higher polyfunctional (meth) acrylate single system include glycerol tri(meth)acrylate, alkoxylated glycerol tri(meth)acrylate, and trimethylolpropane tris(methyl). ) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, neopentyl alcohol tri (meth) acrylate, neopentyl alcohol tetra ( a trifunctional or higher fat such as methyl acrylate, dipentaerythritol tetra(meth) acrylate, dipentaerythritol penta (meth) acrylate, or dipentaerythritol hexa (meth) acrylate Poly(meth) acrylate of a polyhydric alcohol; poly(meth) acrylate of a trifunctional or higher halogen substituted polyol; tris(methyl) of an alkylene oxide adduct of glycerol Acrylate; tris(meth)acrylate of an alkylene oxide adduct of trimethylolpropane; 1,1,1-tris[(methyl)propenyloxyethoxyethoxy]propane; Tris(hydroxyethyl)trimeric isocyanate tri(meth)acrylate or the like.

The (meth)acrylamide mono-system is preferably a (meth) acrylamide having a substituent at the N-position, and a typical example of the substituent at the N-position is an alkyl group, but may also be bonded to (methyl) The nitrogen atom of acrylamide forms a ring together, and the ring may have an oxygen atom as a ring member in addition to a nitrogen atom having a carbon atom and a (meth) acrylamide. Further, a substituent such as an alkyl group or a pendant oxy group (=O) may be bonded to a carbon atom constituting the ring.

Specific examples of the N-substituted (meth) acrylamide include, for example, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-n-propyl (methyl) Acrylamide, N-isopropyl (meth) acrylamide, N-n-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, N-tertiary butyl ( N-alkyl (meth) acrylamide such as methacrylamide or N-hexyl (meth) acrylamide; such as N,N-dimethyl(meth) acrylamide, N,N- N,N-dialkyl(meth)acrylamide such as diethyl (meth) acrylamide. Further, the substituent at the N-position may be an alkyl group having a hydroxyl group, and examples thereof are: N-hydroxymethyl(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide N-(2-hydroxypropyl)(meth)acrylamide. Further, when the substituent at the above N-position is formed into a ring, an N-substituted (meth) acrylamide which forms a 5-membered ring or a 6-membered ring may be exemplified, and specific examples thereof are: N-acrylopyryrrolidine , 3-(methyl)propenyl-2-oxazolidinone, 4-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine Wait.

When the thermoplastic resin film is a polyolefin resin film, (meth) In the case of the acrylic resin film, the radically polymerizable thermoplastic resin film is preferably a monomer containing (meth)acrylamide monomer from the viewpoint of adhesion to the polarizing film.

The (meth)acrylic oligomer having at least two (meth)acrylonitrile groups in the molecule is a urethane (meth)acrylic oligomer or a polyester (meth)acrylic oligomer. An epoxy group (meth)acrylic oligomer or the like.

The urethane (meth)acrylic oligomer is a compound having a urethane bond (-NHCOO-) and at least two (meth) acrylonitrile groups in the molecule. Specifically, it may be a urethanization reaction product of a hydroxyl group-containing (meth)acrylic monomer having at least one (meth)acryl fluorenyl group and at least one hydroxyl group in the molecule, and a polyisocyanate. Or a carbamate compound having an isocyanate group at the terminal obtained by reacting a polyhydric alcohol with a polyisocyanate, and a (meth) group having at least one (meth) acrylonitrile group and at least one hydroxyl group in the molecule. An urethanation reaction product of an acrylic monomer or the like.

The hydroxyl group-containing (meth)acrylic monomer used in the above urethanation reaction may be, for example, a hydroxyl group-containing (meth) acrylate monomer, and specific examples thereof include: (meth)acrylic acid 2-hydroxyl Ethyl ester, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerol di(meth)acrylate , trimethylolpropane di (meth) acrylate, neopentyl alcohol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate. Specific examples other than the hydroxyl group-containing (meth) acrylate monomer include N-hydroxyalkyl groups such as N-hydroxyethyl (meth) acrylamide and N-hydroxymethyl (meth) acrylamide ( Methyl) acrylamide body.

The polyisocyanate to be supplied in the urethanation reaction with the hydroxyl group-containing (meth)acrylic monomer may, for example, be hexamethylene diisocyanate, isocyanuric acid diisocyanate, isophorone diisocyanate or the like. Cyclohexylmethane diisocyanate, toluene diisocyanate, xylene diisocyanate, diisocyanate obtained by hydrogenating aromatic isocyanates in such diisocyanates (for example, hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, etc.), triphenyl A di- or tri-isocyanate such as a methane triisocyanate or a diphenylmethylbenzene triisocyanate; and a polyisocyanate obtained by multiquantifying the above diisocyanate.

Further, the polyol used in the reaction of the polyisocyanate to form the terminally-containing isocyanate-containing carbamate compound may be a polyester other than the aromatic, aliphatic or alicyclic polyol. Polyol, polyether polyol, and the like. Examples of the aliphatic or alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and neopentyl glycol. , trimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylol heptane, dimethylolpropionic acid, dimethylol Butyric acid, glycerin, hydrogenated bisphenol A, and the like.

The polyester polyol is obtained by a dehydration condensation reaction of the above polyol with a polycarboxylic acid or an anhydride thereof. Examples of the polycarboxylic acid or its anhydride include succinic acid (anhydride), adipic acid, maleic acid (anhydride), and itaconic acid (anhydride) when it is an "anhydride". , trimellitic acid (anhydride), pyroghuric acid (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid, hexahydrophthalic acid (anhydride) and the like.

The polyether polyol may be a polyoxyalkylene-modified polyhydric alcohol obtained by reacting the above polyol or dihydroxybenzene with an alkylene oxide, in addition to the polyalkylene glycol.

The polyester (meth)acrylic oligomer has a compound having an ester bond and at least two (meth)acrylonyl groups (typically (meth)acrylenyloxy) in the molecule. Specifically, it can be obtained by a dehydration condensation reaction using (meth)acrylic acid, a polyvalent carboxylic acid or its anhydride, and a polyhydric alcohol. Examples of the polycarboxylic acid or its anhydride used in the dehydration condensation reaction include succinic acid (anhydride), adipic acid, and maleic acid (anhydride) when the anhydride is represented by "(anhydride)". Itaconic acid (anhydride), trimellitic acid (anhydride), pyroghuric acid (anhydride), hexahydrophthalic acid (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid Wait. Further, examples of the polyhydric alcohol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and neopentyl Alcohol, trimethylolethane, trimethylolpropane, ditrimethylolpropane, neopentyl alcohol, dipentaerythritol, dimethylol heptane, dimethylolpropionic acid, dihydroxyl Butyric acid, glycerin, hydrogenated bisphenol A, and the like.

The epoxy (meth)acrylic oligomer can be obtained, for example, by an addition reaction of a polyepoxypropyl ether and (meth)acrylic acid, and has at least two (meth)acrylonitrile groups in the molecule. Oxygen. Examples of the polyepoxypropyl ether used in the addition reaction include ethylene glycol diepoxypropyl ether, propylene glycol diepoxypropyl ether, tripropylene glycol diepoxypropyl ether, and 1,6-hexane. Alcohol diglycidyl ether, bisphenol A diglycidyl ether, and the like.

(2) Other hardening compounds

The curable adhesive composition of the present invention may include a radical polymerizable (meth)acrylic compound and a radical polymerizable compound other than the norbornene-based compound (I). Other examples of the radical polymerizable compound include, for example, a vinyl compound such as styrene, styrenesulfonic acid, vinyl acetate, vinyl propionate or N-vinyl-2-pyrrolidone; A compound having one or more ethylenically unsaturated bonds. The curable adhesive composition may contain one or more other radical polymerizable compounds.

However, from the viewpoint of the durability of the polarizing plate in which the thermoplastic resin film is bonded to the adhesive layer of the cured layer of the curable adhesive composition on one surface or both surfaces of the polarizing film, other The content of the radically polymerizable compound is preferably 50 parts by weight or less based on 100 parts by weight of the radical polymerizable (meth)acrylic compound, more preferably 30 parts by weight or less, and still more preferably 10 parts by weight or less. Better.

In the curable adhesive composition of the present invention, the curable (polymerizable) compound may contain a cationic polymerization reaction and hardening by irradiation or heating of an active energy ray in addition to the radically polymerizable compound. A cationically polymerizable compound which is a monomer or an oligomer. The cationically polymerizable compound may, for example, be an epoxy compound having one or more (preferably two or more) epoxy groups in the molecule (for example, an alicyclic epoxy compound, an aromatic epoxy compound, or a hydrogenated epoxy compound). , an aliphatic epoxy compound, etc.), an oxetane compound having one or more oxetane rings (oxetanyl) in the molecule, an aliphatic or alicyclic vinyl compound, or a cyclic internal An ester compound, a cyclic acetal compound, a cyclic thioether compound, Spiroorthoester compounds and the like. The curable adhesive composition may contain one or more cationically polymerizable compounds.

However, cationic polymerization is carried out from the viewpoint of durability of a polarizing plate in which a thermoplastic resin film is bonded to an adhesive layer of a cured layer of a curable adhesive composition on one surface or both surfaces of a polarizing film. The content of the compound is preferably 100 parts by weight or less, more preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 10 parts by weight or less based on 100 parts by weight of the radically polymerizable compound. Very good.

(3) Free radical polymerization initiator

The curable adhesive composition of the present invention may contain a photoradical polymerization initiator when it is active energy ray curability, and may contain a thermal radical polymerization initiator when it is thermosetting. In the case of electron beam curability, the photoradical polymerization initiator is not necessarily required, but in the case of ultraviolet curability or the like, the curable adhesive composition of the present invention contains a photoradical polymerization initiator. good. When it is an active energy ray hardenability, especially when it is ultraviolet curable, a photoradical polymerization initiator can be used together with a thermal radical polymerization initiator. The photoradical polymerization initiator is a polymerization initiator which initiates a radical curable compound by irradiation with an active energy ray such as visible light, ultraviolet light, X-ray or electron beam. The curable adhesive composition may contain one or more kinds of radical polymerization initiators.

As the photoradical polymerization initiator and the thermal radical polymerization initiator, those conventionally used can be used. Specific examples of the photoradical polymerization initiator include: acetophenone, 3-methylacetophenone, benzoin dimethyl ketal (benzil) Dimethylketal), 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl-2-( Acetophenone-based initiators such as N-folininyl)propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; diphenyl ketone, 4-chloro-di Diphenylketone-based initiators such as phenyl ketone and 4,4'-diaminodiphenyl ketone; benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; 4-isopropylthioxene Thioxanthone such as ketone is an initiator; others such as xanthone, anthrone, camphorquinone, benzaldehyde, hydrazine.

The content of the radical polymerization initiator is generally 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, per 100 parts by weight of the radically polymerizable compound. By containing 0.5 part by weight or more of the radical polymerization initiator, the radically polymerizable compound can be sufficiently cured, and the obtained polarizing plate can be imparted with high mechanical strength and adhesion strength. On the other hand, when the amount is too large, the durability of the polarizing plate may be lowered.

(4) Decene-based compound (I)

The curable adhesive composition of the present invention contains the norbornene-based compound (I) represented by the following formula (I).

In the formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent a H atom or a substituent containing at least one hetero atom selected from the group consisting of an O atom and an N atom. When all of R ¹ , R ² , R ³ and R ⁴ are H atoms, the norbornene-based compound (I) is 2-northene.

The norbornene-based compound (I) is preferably one of R ¹ , R ² , R ³ and R ⁴ as the substituent, and at least one of R ¹ , R ² , R ³ and R ⁴ . It is more preferred that one or both of them are the above substituents. When the norbornene-based compound (I) contains at least one of the above substituents, each structural configuration of the substituent may be an endo, an exo or a mixture thereof.

The above-mentioned substituent is from the viewpoint of durability of a polarizing plate obtained by bonding a thermoplastic resin film to an adhesive layer of a cured layer of a curable adhesive composition on one surface or both surfaces of a polarizing film. selected to comprise -C (= O) -, - OH and NH ₂ groups are formed by at least one of configuration is preferred. A specific example of a substituent comprising a structure of -C(=O)-[carboxy]-C(=O)-O-alkyl, -C(=O)-NH-alkyl, -C(=O) -alkyl, -C(=O)-H, -C(=O)-OH, -C(=O)-NH ₂ , OC(=O)-alkyl. The "alkyl group" in the substituents are each independently, and may be, for example, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, a linear chain or a branched chain having 1 to 4 carbon atoms or A cyclic alkyl group is preferred. At least one hydrogen atom of the "alkyl group" in the above substituent may be substituted with a group selected from the group consisting of -OH and -NH ₂ .

Further, a specific example of the substituent including the structure of -OH is -OH, -alkyl-OH which is directly bonded to the norbornene ring. Specific examples of the group comprising -NH substituent of structure ₂ is based on a norbornene ring directly bonded -NH _2, - alkylene -NH _2. The "alkylene group" in the substituent -alkylene-OH and -alkylene-NH ₂ are each independently, and may be, for example, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. A linear or branched alkyl group having 1 to 4 carbon atoms is preferred. At least one hydrogen atom of the "alkylene group" in the above substituent may be substituted with a group selected from the group consisting of -OH and -NH ₂ .

Examples of the norbornene-based compound (I) having the above substituent are shown below together with the chemical formula.

[a] a norbornene-based compound having a substituent -C(=O)-O-alkyl group (I): a-1:5-northene-2-carboxylic acid methyl ester, a-2:5-lower Terpene-2-carboxylic acid tert-butyl butyl ester, a-3:5-norbornene-2-carboxylic acid (2-aminoethyl) ester, a-4:5-norprene-2,3-dicarboxylic acid Monomethyl ester.

[b] Decalene-based compound (I) having a substituent -C(=O)-NH-alkyl group: b-1:5-northene-(N-2-hydroxyethyl)-2-carboxylate Guanamine.

[c] A decene-based compound (I) having a substituent -C(=O)-alkyl group: c-1: 5-ethenyl-2-northene.

[d] Decene-based compound (I) having a substituent -C(=O)-H: d-1:5-nordecene-2-carboxaldehyde.

[e] a norbornene-based compound (I) having a substituent -C(=O)-OH: e-1:5-nordecene-2-carboxylic acid, e-2:5-nordecene-2, 3-dicarboxylic acid.

[f] A decene-based compound (I) having a substituent -C(=O)-NH ₂ : f-1:5-nordecene-2-carboxamide.

[g] Decamethene-based compound (I) having a substituent -O-C(=O)-alkyl group: g-1: 5-northen-2-yl acetate.

[h] Decene-based compound (I) having a substituent -OH: h-1:5-nordecene-2-ol, h-2:5-nordecene-2-methanol, h-3: 5-northene-2,2-dimethanol, h-4:5-norbornene-2,3-dimethanol (endo, endo, endo, or exosome, exosome ( Exo, exo), etc.).

[i] A decene-based compound (I) having a substituent -NH ₂ : i-1: 5-amino-2-northene, i-2: 5-northene-2-methylamine.

As described above, when R ¹ and R ³ are a hydrogen atom and R ² and R ⁴ are the above substituents, R ² and R ⁴ may form a ring together with the two C atoms of the bonded decene ring. structure. Examples of the ring structure include a cyclic quinone imine structure and a cyclic acid anhydride structure. Examples of the norbornene-based compound (I) having a substituent forming a ring structure are shown below together with the chemical formula.

[j] A norbornene-based compound (I) having a substituent forming a ring structure: j-1:5-northene-2,3-dimethylimine, j-2:5-norbornene- 2,3-Dicarboxylic anhydride.

The curable adhesive composition of the present invention may contain one or more kinds of norbornene-based compounds (I). When two or more kinds of the decene-based compound (I) are contained, for example, a compound having the same chemical composition but a structure in which the substituent is an endo is used as the exo (exo) The case of a compound configured in a configuration. Among them, from the viewpoint of the bonding strength of the polarizing plate and the thermoplastic resin film, even the durability of the polarizing plate, to have -C(=O)-O-alkyl, -C(=O)-NH-alkane A norbornene-based compound (I) which is a substituent of any one of the group of -alkyl-NH ₂ , -OH and -NH ₂ (preferably any one or both) is suitable, The compounds (a-1), (a-3), (b-1) and the like are more suitably used, and the compounds (a-3), (b-1) and the like are particularly suitable.

From the viewpoint of durability of a polarizing plate obtained by laminating a thermoplastic resin film on the one surface or the both surfaces of the polarizing film via the adhesive layer of the cured layer of the curable adhesive composition, the decene-based system The content of the compound (I) is preferably 0.001 part by weight or more, and more preferably 0.01 part by weight or more based on 100 parts by weight of the total of the radical polymerizable (meth)acrylic compound and the norbornene compound (I). More preferably, it is more preferably 0.05 parts by weight or more. The content of the decylene-based compound (I) is generally 20 parts by weight or less per 10 parts by weight based on 100 parts by weight of the total of the radically polymerizable (meth)acrylic compound and the norbornene-based compound (I). The following are preferred, It is more preferably 6 parts by weight or less, more preferably 5 parts by weight or less.

(5) Additives

The curable adhesive composition of the present invention may contain an additive as needed. Specific examples of the additive include: ion trapping agent, antioxidant, chain transfer agent, polymerization accelerator, sensitizer, sensitizer, light stabilizer, viscosity agent, thermoplastic resin, filler, flow control agent, plastic Chemical agent, antifoaming agent, leveling agent, decane coupling agent, pigment, antistatic agent, ultraviolet absorber, photo or thermal cationic polymerization initiator. The photo or thermal cationic polymerization initiator is added when a cationically polymerizable compound is used in combination as a curable compound. Examples of the ion trapping agent include inorganic compounds such as a powdery lanthanum, lanthanide, magnesium, aluminum, calcium, titanium, and the like. Examples of the antioxidant include a hindered phenol antioxidant.

<Polarizer>

The curable adhesive composition of the present invention is suitably used as an adhesive for a polarizing film which constituting a polarizing plate and a thermoplastic resin film such as a protective film laminated thereon. In other words, the polarizing plate of the present invention comprises a polarizing film and a thermoplastic resin film laminated on at least one surface thereof via an adhesive layer formed of the curable adhesive composition of the present invention. The adhesive layer is a layer of a cured product formed by curing the above-described curable adhesive composition of the present invention. In the polarizing plate of the present invention, the polarizing film and the thermoplastic resin film are bonded to the curable adhesive composition of the present invention described above, and thus exhibit excellent durability (adhesive strength between two films and thermal shock resistance).

(1) Composition of polarizing plate

Examples of the layer configuration of the polarizing plate of the present invention are shown in Figs. 1 and 2 . As shown in Fig. 1, the polarizing plate of the present invention may be a polarizing film 30 and a first thermoplastic resin film 10 laminated on one surface thereof via a first adhesive layer 15. Further, as shown in FIG. 2, the polarizing plate of the present invention may be a first thermoplastic resin film 10 including a polarizing film 30, laminated on one surface thereof via a first adhesive layer 15, and a polarizing film 30. The second thermoplastic resin film 20 laminated on the other surface via the second adhesive layer 25 is laminated. When the polarizing plate has the first adhesive layer 15 and the second adhesive layer 25, either of them may be formed of the curable adhesive composition of the present invention, or both adhesive layers may be cured by the curability of the present invention. The composition of the composition of the agent is preferred from the viewpoint of durability.

The polarizing plate of the present invention may include other layers (or films) other than the above, without being limited to the examples of Figs. 1 and 2. Specific examples of the other layers include, for example, an adhesive layer laminated on the outer surfaces of the first thermoplastic resin film 10, the second thermoplastic resin film 20, and/or the polarizing film 30; and a layer deposited on the outer surface of the adhesive layer a separator (also referred to as a "peeling film"); a protective film (also referred to as a "surface protective film") laminated on the outer surfaces of the first thermoplastic resin film 10, the second thermoplastic resin film 20, and/or the polarizing film 30. An optical functional film (or layer) or the like which is laminated on the outer surfaces of the first thermoplastic resin film 10, the second thermoplastic resin film 20, and/or the polarizing film 30 via an adhesive layer or an adhesive layer.

(2) polarizing film

The polarizing film 30 is a film having a function of selectively transmitting linearly polarized light in a certain direction from natural light. For example, an iodine-based polarizing film obtained by adsorbing/oriented iodine as a dichroic dye to a polyvinyl alcohol-based resin film, and a dichroic dye as a dichroic dye are adsorbed/oriented to a polyvinyl alcohol-based resin. A dye-based polarizing film made of a film; and a coating-type polarizing film obtained by coating and orienting/fixing a dichroic dye in a lyotropic liquid crystal state. These polarizing films are used to selectively transmit linearly polarized light in one direction from natural light and absorb linearly polarized light in the other direction, and are therefore referred to as absorption type polarizing films. The polarizing film 30 is not limited to the absorbing polarizing film, and may be a reflective polarizing film that selectively transmits linear polarized light in one direction from natural light and reflects linear polarized light in the other direction, or a straight line that scatters the other direction. The polarized scattering type polarizing film is preferably an absorbing polarizing film from the viewpoint of excellent visibility. In particular, a polyvinyl alcohol-based polarizing film made of a polyvinyl alcohol-based resin is more preferable, and a polyethylene obtained by adsorbing/oriented a dichroic dye such as iodine or a dichroic dye to a polyvinyl alcohol-based resin film is used. The alcohol-based polarizing film is more preferably a polyvinyl alcohol-based polarizing film in which iodine is adsorbed/oriented to a polyvinyl alcohol-based resin film.

The polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based polarizing film may be one obtained by saponifying a polyvinyl acetate-based resin. The polyvinyl acetate-based resin may, for example, be a copolymer of a monomer which is copolymerizable with vinyl acetate, and the like, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include: unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated Sulfonic acids, and (meth)acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is generally from about 85 to 100 mol%, preferably from 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, an aldehyde-modified polyvinyl formal or a polyvinyl acetal may be used. The average degree of polymerization of the polyvinyl alcohol-based resin is generally from about 1,000 to 10,000, preferably from about 1,500 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin is obtained in accordance with JIS K 6726.

A film made of such a polyvinyl alcohol-based resin is used as a germ film of the polarizing film 30. The film formation method of the polyvinyl alcohol-based resin is not particularly limited, and a conventional method is employed. The thickness of the polyvinyl alcohol-based germplasm film is, for example, 150 μm or less, and preferably 100 μm or less (for example, 50 μm or less).

The polarizing film 30 can be produced by a method comprising the steps of: uniaxially stretching a polyvinyl alcohol-based resin; and adsorbing the polyvinyl alcohol-based resin film by a dichroic dye to adsorb the dichroic dye. a step of treating a polyvinyl alcohol-based resin film having a dichroic dye adsorbed by an aqueous solution of boric acid (crosslinking treatment); and a step of washing with water after treatment with an aqueous solution of boric acid.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be carried out before dyeing of the dichroic dye, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching can be carried out before boric acid treatment or boric acid treatment. Moreover, uniaxial stretching can be performed in a plurality of stages.

When uniaxially stretched, it can be moved between rolls with different circumferential speeds. Uniaxial stretching can also be carried out using a hot roll for uniaxial stretching. Further, the uniaxial stretching may be a dry stretching in which stretching is carried out in the air, or may be a wet stretching in which a polyvinyl alcohol-based resin film is stretched in a state of being swollen using a solvent or water. The draw ratio is generally about 3 to 8 times.

A method of dyeing a polyvinyl alcohol-based resin film as a dichroic dye may be, for example, a method in which the film is immersed in an aqueous solution containing a dichroic dye. The dichroic dye system uses iodine or a dichroic organic dye. Further, the polyvinyl alcohol-based resin film is preferably subjected to immersion treatment in water before the dyeing treatment.

The dyeing treatment with iodine is generally carried out by impregnating a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide. The iodine content in the aqueous solution may be about 0.01 to 1 part by weight per 100 parts by weight of water. The content of potassium iodide may be about 0.5 to 20 parts by weight per 100 parts by weight of water. Moreover, the temperature of the aqueous solution may be about 20 to 40 °C. On the other hand, the dyeing treatment by a dichroic organic dye is generally a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic organic dye. The aqueous solution containing a dichroic organic dye may contain an inorganic salt such as sodium sulfate as a dyeing auxiliary. The content of the dichroic organic dye in the aqueous solution may be about 1 × 10 ^-4 to 10 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution may be about 20 to 80 °C.

The boric acid treatment after dyeing with a dichroic dye is generally carried out by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid. When iodine is used as the dichroic dye, the boric acid is contained The aqueous solution is preferably one containing potassium iodide. The boric acid content in the aqueous solution containing boric acid may be about 2 to 15 parts by weight per 100 parts by weight of water. The potassium iodide content in the aqueous solution may be from about 0.1 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution may be 50 ° C or higher, for example, 50 to 85 ° C.

The polyvinyl alcohol-based resin film after boric acid treatment is generally subjected to a water washing treatment. The water washing treatment can be carried out, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing treatment is generally about 5 to 40 °C. After washing with water, drying treatment was carried out to obtain a polarizing film 30. The drying treatment can be carried out using a hot air dryer or a far infrared heater. A polarizing plate can be obtained by laminating a thermoplastic resin film such as a protective film on one surface or both surfaces of the polarizing film 30 using a curable adhesive composition or the like.

Further, other examples of the method for producing the polarizing film 30 include a method described in, for example, JP-A-2000-338329 or JP-A-2012-159778. In this method, a solution containing a polyvinyl alcohol-based resin is applied to the surface of the base film to form a resin layer, and then the laminated film including the base film and the resin layer is stretched, and then subjected to a dyeing treatment, a crosslinking treatment, or the like, that is, A polarizer layer (polarizing film layer) is formed of a resin layer. The polarizing laminated film including the base film and the polarizer layer is bonded to a thermoplastic resin film such as a protective film on the surface of the polarizer, and then the base film is peeled off and removed to form a polarized light as shown in FIG. board. When the thermoplastic resin film is further bonded to the surface of the polarizer exposed by the release of the base film, the polarizing plate having the structure shown in Fig. 2 is obtained.

The thickness of the polarizing film 30 may be 40 μm or less, preferably 30 μm or less (for example, 20 μm or less, more preferably 15 μm or less, and still more preferably 10 μm or less). The thin film polarizing film 30 can be more easily produced by the method described in JP-A-2000-338329 or JP-A-2012-159778. The thickness of the polarizing film 30 is more preferably 20 μm or less, more preferably 15 μm or less, and still more preferably 10 μm or less. The thickness of the polarizing film 30 is generally 2 μm or more. When the thickness of the polarizing film 30 becomes small, it is advantageous for the polarizing plate and even the thinning of the image display device.

(3) Thermoplastic resin film

Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be a film containing light transmissive (preferably optically transparent), for example, a chain polyolefin resin (polypropylene resin) a polyolefin-based resin such as a cyclic polyolefin resin (such as a decene-based resin); a cellulose ester-based resin such as triacetyl cellulose or diethyl phthalocyanine; for example, polyethylene terephthalate A polyester resin such as an ester, polyethylene naphthalate or polybutylene terephthalate; a polycarbonate resin; a (meth)acrylic resin; or a mixture or a copolymer thereof. In particular, each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is preferably selected from the group consisting of a polyester resin, a polycarbonate resin, a polyolefin resin, a (meth)acrylic resin, and a cellulose ester system. The resin is composed of a group of resins.

Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be an unstretched film or a film that is uniaxially or biaxially stretched. Either. The biaxial stretching may be biaxial stretching while performing simultaneous stretching in two stretching directions, or may be sequential biaxial stretching after stretching in a predetermined direction and stretching in other directions. The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be a protective film for protecting the polarizing film 30, or may be a protective film having an optical function such as a retardation film. The retardation film is an optical functional film used for the purpose of compensating for a phase difference or the like caused by a liquid crystal cell belonging to an image display element. For example, a phase imparted with an arbitrary phase difference can be formed by stretching (uniaxial stretching or biaxial stretching) of the film containing the thermoplastic resin or forming a liquid crystal layer or the like on the thermoplastic resin film. Poor film.

In addition to a homopolymer of a chain olefin such as a polyethylene resin or a polypropylene resin, a chain polyolefin resin may be a copolymer containing two or more kinds of chain olefins.

The cyclic polyolefin-based resin is a resin containing a cyclic olefin represented by a norbornene or tetracyclododecene (alias: dimethicone) or such a derivative as a polymerization unit. General name. Specific examples of the cyclic polyolefin-based resin include a ring-opened (co)polymer of a cyclic olefin, a hydrogenated product thereof, an addition polymer of a cyclic olefin, a cyclic olefin such as ethylene or propylene, and the like. A copolymer of a chain olefin or an aromatic compound having a vinyl group, and a modified (co)polymer obtained by modifying the unsaturated carboxylic acid or a derivative thereof. Among them, a norbornene-based resin using a norbornene-based monomer such as a norbornene- or polycyclic norbornene-based monomer as a cyclic olefin is suitable.

The cellulose ester resin is at least a hydroxyl group in the cellulose A portion of the acetated resin may also be a mixed ester that is partially acetated and partially esterified with other acids. The cellulose ester-based resin is preferably an acetaminocellulose-based resin. Specific examples of the acetaminophen-based resin include, for example, triethyl hydrazine cellulose, diethyl hydrazine cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like.

The polyester resin is a resin other than the cellulose ester resin having an ester bond, and generally includes a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. Specific examples of the polyester resin include: polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate Diester, propylene naphthalate, dimethyl dimethyl terephthalate, cyclohexane dimethyl phthalate. Among them, polyethylene terephthalate is suitable from the viewpoints of mechanical properties, solvent resistance, scratch resistance, cost, and the like. The polyethylene terephthalate refers to a resin composed of polyethylene terephthalate of 80 mol% or more of the repeating unit, and may contain a constituent unit derived from another copolymerized component.

The other copolymerization component is a dicarboxylic acid component and a diol component. Examples of the dicarboxylic acid component include isophthalic acid, 4,4'-dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ketone, bis(4-carboxyphenyl)ethane, and adipic acid. , azelaic acid, sodium 5-sulfoisophthalate, 1,4-dicarboxycyclohexane, and the like. Examples of the diol component include propylene glycol, butylene glycol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and poly Butylene glycol and the like. The dicarboxylic acid component and the diol component may be used in combination of two or more kinds as needed. Moreover, the above dicarboxylic acid component and diol are formed A hydroxycarboxylic acid such as p-hydroxybenzoic acid or p-β-hydroxyethoxybenzoic acid can be used in combination. As the other copolymerization component, a dicarboxylic acid component and/or a diol component having a guanamine bond, a urethane bond, an ether bond, a carbonate bond or the like can be used in a small amount.

The polycarbonate resin is a polyester formed of carbonic acid and a diol or bisphenol. Among them, from the viewpoint of heat resistance, weather resistance, and acid resistance, an aromatic polycarbonate having a diphenyl alkane in a molecular chain is suitable. The polycarbonate is exemplified by 2,2-bis(4-hydroxyphenyl)propane (alias bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis (4) A polycarbonate derived from a bisphenol such as -hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)isobutane or 1,1-bis(4-hydroxyphenyl)ethane.

The (meth)acrylic resin may be a polymer having methacrylate as a main monomer (containing 50% by weight or more), and preferably a copolymer having a small amount of other copolymerized components. The (meth)acrylic resin is preferably a copolymer of methyl methacrylate and methyl acrylate, and may be further copolymerized with the third monofunctional monomer.

Examples of the third monofunctional monomer include, for example, ethyl methacrylate, methacrylic acid n- or iso- or tertiary butyl ester, cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid. a methacrylate other than methyl methacrylate such as benzyl ester, 2-ethylhexyl methacrylate or 2-hydroxyethyl methacrylate; ethyl acrylate, n- or iso- or tert-butyl acrylate Acrylates such as cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate; such as methyl 2-(hydroxymethyl)acrylate, 2-(1- Hydroxyethyl)methyl acrylate, 2-(hydroxyl a hydroxyalkyl acrylate such as ethyl (meth) acrylate or 2-(hydroxymethyl) acrylate as a normal or iso- or tertiary butyl ester; an unsaturated acid such as methacrylic acid or acrylic acid; such as chlorostyrene or bromine a halogenated styrene such as styrene; a substituted styrene such as vinyl toluene or α-methylstyrene; an unsaturated nitrile such as acrylonitrile or methacrylonitrile; and an unsaturated such as maleic anhydride or citraconic anhydride An acid anhydride; an unsaturated quinone imine such as phenyl maleimide or cyclohexylmaleimine. The third monofunctional single system may be used alone or in combination of two or more.

In the (meth)acrylic resin, the polyfunctional monomer can be further copolymerized. Examples of the polyfunctional single system include, for example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol II. Ethylene glycol such as (meth) acrylate, nonaethylene glycol di(meth) acrylate or tetradecyl ethylene glycol di(meth) acrylate or an oligomer thereof having a terminal hydroxyl group via (meth)acrylic acid The esterified person; the terminal hydroxyl group of propylene glycol or its oligomer is esterified with (meth)acrylic acid; such as neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, A hydroxyl group of a glycol such as butanediol di(meth)acrylate is esterified with (meth)acrylic acid; a bisphenol A, an alkylene oxide adduct of bisphenol A, or a halogen substituent thereof a hydroxyl group at both ends of which is esterified with (meth)acrylic acid; a polyol such as trimethylolpropane or neopentyl alcohol is esterified with (meth)acrylic acid, and (meth) in the terminal hydroxyl group An epoxy-based ring-opening addition of glycidyl acrylate; a dibasic acid such as succinic acid, adipic acid, terephthalic acid, phthalic acid, such halogen substituents, and the like Epoxy Manipulation adducts of (meth) acrylate, glycidyl methacrylate epoxy ring-opening addition of persons; (meth) acrylate, An aryl ester; an aromatic divinyl compound such as divinylbenzene. Among them, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and neopentyl glycol di(meth)acrylate are suitable.

The (meth)acrylic resin may be modified by further reacting the functional groups of the copolymer. Examples of the reaction include, for example, a polymer chain deco-methanol condensation reaction of a methyl ester group of methyl (meth)acrylate with a hydroxyl group of methyl 2-(hydroxymethyl)acrylate, and a carboxyl group of (meth)acrylic acid. A polymer chain internal dehydration condensation reaction of a hydroxyl group of methyl 2-(hydroxymethyl)acrylate.

The glass transition temperature of the (meth)acrylic resin is preferably from 80 to 160 °C. The glass transition temperature can be adjusted by adjusting the polymerization ratio of the methacrylate monomer and the acrylate monomer, the carbon chain length of the respective ester groups, the kinds of the functional groups, and the monomers. The polymerization ratio of the entire polyfunctional monomer is controlled.

Further, the means for increasing the glass transition temperature of the (meth)acrylic resin is also effective in introducing a ring structure into the main chain of the polymer. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic quinone imine structure, or a lactone structure. Specific examples thereof include a cyclic acid anhydride structure such as a glutaric anhydride structure or a succinic anhydride structure; a pentanediamine structure; a succinimide structure; a cyclic quinone imine structure; a butyrolactone and a valerolactone; Ester structure. The larger the ring structure content in the main chain, the higher the glass transition temperature of the (meth)acrylic resin. The cyclic acid anhydride structure and the cyclic quinone imine structure system can be introduced by a method in which a monomer having a cyclic structure such as maleic acid or maleimide is copolymerized and introduced. Dehydration after polymerization / A method of introducing a cyclic acid anhydride structure by a methanol decondensation reaction, a method of introducing a cyclic quinone imine structure by reacting an amine compound, and the like. The resin (polymer) having a lactone ring structure can be obtained by heating a hydroxyl group and an ester group in the obtained polymer after preparing a polymer having a hydroxyl group and an ester group in the polymer chain. A method of forming a lactone ring structure by cyclization condensation in the presence of a catalyst such as an organic phosphorus compound.

The (meth)acrylic resin may contain an additive as needed. Examples of the additive include a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light stabilizer, an impact modifier, a surfactant, and the like. These additives may be used when a thermoplastic resin other than a (meth)acrylic resin is used as the thermoplastic resin constituting the thermoplastic resin film.

The (meth)acrylic resin may contain acrylic rubber particles as an impact modifier, from the viewpoint of film formability at the time of film formation and impact resistance of the film. The acrylic rubber particles are particles in which an elastic polymer mainly composed of acrylate is used as an essential component, and examples thereof include a single-layer structure consisting essentially of only the elastic polymer, and the elastic polymer is used therein. A multi-layered constructor of 1 layer. Examples of the elastic polymer include a crosslinked elastic copolymer obtained by copolymerizing an alkyl acrylate as a main component and another vinyl monomer and a crosslinkable monomer copolymerizable therewith. Examples of the alkyl acrylate which is a main component of the elastic polymer include those in which an alkyl group such as methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate has a carbon number of from 1 to 8. However, an alkyl acrylate having an alkyl group having 4 or more carbon atoms is suitable. Can be used with the acrylic The other ethylene-based single system in which the alkyl ester is copolymerized may, for example, be a compound having one polymerizable carbon-carbon double bond in the molecule, and more specifically, a methacrylate such as methyl methacrylate may be mentioned. An aromatic vinyl compound such as styrene or a vinyl cyanide compound such as acrylonitrile. The crosslinkable single system may, for example, be a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, for example, ethylene glycol di(meth)acrylate or butyl Polyol di(meth)acrylates such as diol di(meth)acrylate; enesters of (meth)acrylic acid such as allyl (meth)acrylate; divinylbenzene and the like.

A laminate composed of a film composed of a (meth)acrylic resin containing no rubber particles and a film composed of a (meth)acrylic resin containing rubber particles may also be used as a protective film. In addition, a (meth)acrylic resin layer may be formed on one surface or both surfaces of a phase difference expression layer composed of a resin different from the (meth)acrylic resin, and a phase difference may be exhibited as a protective film.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may contain an ultraviolet absorber. When the polarizing plate is used in an image display device such as a liquid crystal display device, when the protective film containing the ultraviolet absorbing agent is disposed on the identification side of the image display element (for example, a liquid crystal cell), the image display element can be suppressed from being caused by ultraviolet rays. Deterioration. Examples of the ultraviolet absorber include a salicylate-based compound, a diphenylketone-based compound, a benzotriazole-based compound, a cyanoacrylate-based compound, and a nickel-salted salt-based compound.

First thermoplastic resin film 10 and second thermoplastic resin film 20 may be a film composed of the same thermoplastic resin, or a film composed of mutually different thermoplastic resins. The thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be the same or different depending on the thickness, the presence or absence of the additive, the type thereof, and the phase difference characteristics.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be provided on the outer surface thereof (the surface opposite to the polarizing film 30) such as a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, and an anti-reflection layer. A surface treatment layer (cover layer) such as an electrostatic layer, an antifouling layer, or a conductive layer.

The thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 are usually 5 to 200 μm, preferably 10 to 120 μm, and more preferably 10 to 85 μm. When the thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is reduced, it is advantageous for the polarizing plate to reduce the thickness of the image display device.

(4) Manufacture of polarizing plates

By laminating the first thermoplastic resin film 10 on the surface of one surface of the polarizing film 30 via the first adhesive layer 15, the polarizing plate having the configuration shown in Fig. 1 can be obtained, and the other surface of the polarizing film 30 can be interposed. The second thermoplastic resin film 20 is further laminated on the second adhesive layer 25 to obtain a polarizing plate having the structure shown in Fig. 2 . When a polarizing plate having both the first thermoplastic resin film 10 and the second thermoplastic resin film 20 (hereinafter, collectively referred to as "thermoplastic resin film") can be produced, the thermoplastic resin film can be gradually single-sided. The laminate may be followed by laminating a double-sided thermoplastic resin film.

The first adhesive layer in the polarizing plate shown in Fig. 1 15 is a cured layer of the curable adhesive composition of the present invention. In the polarizing plate having the configuration shown in Fig. 2, at least one of the first adhesive layer 15 and the second adhesive layer 25 is a cured layer of the curable adhesive composition of the present invention. From the viewpoint of durability, it is preferred that both of the adhesive layers are the cured layer of the curable adhesive composition of the present invention. Further, from the viewpoint of durability, in particular, thermal shock resistance, the adhesive layer of the polarizing plate (having at least one of the first adhesive layer 15 and the second adhesive layer 25) is followed by two The agent layer is preferred. The storage modulus at 80 ° C is preferably 800 MPa or more.

The polarizing film 30 and the thermoplastic resin film are specifically formed by applying a binder composition to the bonding surface of the polarizing film 30 and/or the bonding surface of the thermoplastic resin film, The film of both of them is superimposed on the coating layer of the adhesive composition, and is bonded to the upper and lower sides by a bonding roll or the like, and then irradiated with an active energy ray to be cured (for example, an active energy ray-curable adhesive composition) When it is heated or hardened (as in the case of a thermosetting adhesive composition). Even when the active energy ray-curable adhesive composition is used, the heat treatment can be performed while irradiating the active energy ray or after the irradiation of the active energy ray. Before the coating layer of the adhesive composition is formed, saponification treatment, corona discharge treatment, plasma treatment, flame treatment, primer treatment may be performed on one or both sides of the bonding surface of the polarizing film 30 and the thermoplastic resin film. , anchor coating treatment, etc. are easy to handle.

The coating layer of the subsequent composition can be formed by various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater. Also, A method in which the bonding surface of both of the polarizing film 30 and the thermoplastic resin film is continuously supplied while the adhesive composition is cast therebetween is employed.

From the viewpoint of coatability, the curable adhesive composition of the present invention preferably has a low viscosity. Specifically, the viscosity at 25 ° C is preferably 1000 MPa or less, more preferably 500 MPa or less, and even more preferably 100 MPa or less. The curable adhesive composition of the present invention may be a solventless type, but may contain an organic solvent in order to adjust the viscosity suitable for the coating method to be employed.

Further, in the step of forming the coating layer of the adhesive composition or the step of laminating the polarizing film 30 and the thermoplastic resin film, at least one of the thermoplastic resin film and the adhesive composition may be heated. Thereby, the adhesion between the polarizing film 30 and the thermoplastic resin film is improved, and in particular, the adhesion between the thermoplastic resin film and the adhesive layer is improved. Specific examples of the heating include heating of a thermoplastic resin film, heating of an adhesive composition, heating of a laminated body in which a polarizing film 30 and a thermoplastic resin film are laminated via an unhardened adhesive layer, and the like. For the method of heating the thermoplastic resin film or the laminate, for example, a method in which a long thermoplastic resin film or a laminate is sequentially irradiated with radiant heat by an infrared heater or the like, or a long thermoplastic resin film or laminate is used. A method in which a heated gas is blown by using a blower or the like. Further, the heating method of the adhesive composition may be, for example, a method in which the adhesive composition is heated and kept in the storage tank in advance, and the heated adhesive composition is supplied to the coating device. The heating temperature of the thermoplastic resin film, the adhesive composition or the laminate is 30 to 80 ° C. Good, preferably 40 to 60 ° C. When the heating temperature exceeds 80 ° C, the thermoplastic resin film, the adhesive composition, or the laminate may be deteriorated by heat. Further, when the heating temperature is less than 30 ° C, the effect of improving the adhesion between the thermoplastic resin film and the polarizing film 30 tends to be insufficient.

The light source of the active energy ray may be, for example, ultraviolet light, electron beam, or X-ray. The active energy ray is preferably ultraviolet light. The ultraviolet light source is preferably a light source having a light-emitting distribution at a wavelength of 400 nm or less, and examples thereof include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excited mercury lamp, and a mercury lamp. , metal halide lamps, etc.

The irradiation intensity of the active energy ray to the adhesive layer is determined depending on each of the adhesive compositions, and it is preferred that the light irradiation intensity in the wavelength region in which the activation of the photopolymerization initiator is effective is 1 to 1000 mW/cm ² . When the light irradiation intensity is too small, the reaction time may be too long. On the other hand, when the light irradiation intensity is too large, yellowing of the adhesive layer may occur due to heat generated from the lamp and heat generated during polymerization of the adhesive composition. The deterioration of the polarizing film 30 or the possibility of defective film of the thermoplastic resin film. Further, the light irradiation time of the adhesive layer is also controlled by each of the adhesive compositions, and is set such that the cumulative light amount expressed as a product of the light irradiation intensity and the light irradiation time is 10 to 5000 mJ/cm ² . good. When the amount of accumulated light is too small, the active species derived from the photopolymerization initiator are insufficient, and there is a possibility that the obtained adhesive layer is insufficiently hardened. On the other hand, when the accumulated amount of light is too large, the light irradiation time becomes long. It is not conducive to the improvement of productivity.

When manufacturing the polarizing plate shown in Fig. 2, it will be thermoplastic The timing at which the resin film is laminated on the polarizing film 30 via the coating layer of the adhesive composition and the timing at which the coating layer is cured are not particularly limited. For example, one of the thermoplastic resin films may be laminated, and then the coating layer may be cured, and then the other thermoplastic resin film may be laminated to cure the coating layer. Alternatively, the two sides of the thermoplastic resin film may be laminated sequentially or simultaneously, and then the coating layers on both sides may be simultaneously cured. Further, the irradiation of the active energy ray can be performed by the thermoplastic resin film on either side. For example, when one of the thermoplastic resin films contains the ultraviolet absorber and the other thermoplastic resin film does not contain the ultraviolet absorber, it is preferred to irradiate the active energy ray from the side of the thermoplastic resin film containing no ultraviolet absorber. By such irradiation, the active energy ray to be irradiated is effectively utilized, and the hardening speed can be increased.

The active energy ray can be irradiated while being applied to the laminated body in which the polarizing film 30 and the thermoplastic resin film are laminated via the uncured adhesive layer, while being wound around the roll. Further, in order to improve the reactivity of the adhesive composition, the polarizing plate may be heated while irradiating the active energy ray or after illuminating the active energy ray. The heating temperature is not particularly limited, and is generally below the glass transition temperature of the thermoplastic resin film.

The thickness of the first and second adhesive layers 15 and 25 after the curing is generally 20 μm or less, preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less. When the thickness of the first and second adhesive layers 15 and 25 is too large, the reaction rate of the adhesive composition is lowered, and the moist heat resistance of the polarizing plate tends to be deteriorated. The thickness of the first and second adhesive layers 15 and 25 is generally 0.01 μm or more, and preferably 0.1 μm or more. The thicknesses of the first and second adhesive layers 15, 25 may be the same or different.

(5) Other constituent elements of the polarizing plate (5-1) Optical functional film

The polarizing plate may be provided with an optical functional film other than the polarizing film 30 in order to impart a desired optical function, and one of preferable examples is a retardation film. As described above, the first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may also serve as a retardation film. Alternatively, a retardation film may be laminated in addition to the thermoplastic resin film. In the latter case, the retardation film may be laminated on the outer surfaces of the first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 via the adhesive layer or the adhesive layer. Further, a retardation film may be laminated instead of the thermoplastic resin film. For example, a single-sided protective polarizing plate in which the first thermoplastic resin film 10 is bonded to one surface of the polarizing film 30 shown in Fig. 1 is attached, and a retardation film is bonded to the other surface of the polarizing film 30. The composition. In this case, the retardation film may be laminated on the surface of the polarizing film 30 via the adhesive layer or the adhesive layer.

Specific examples of the retardation film include a birefringent film composed of a stretched film of a translucent thermoplastic resin, a disk-shaped liquid crystal or a film in which a nematic liquid crystal is directionally fixed, and formed on a substrate film. There are those above the liquid crystal layer. The base film generally means a film containing a thermoplastic resin, and the thermoplastic resin is a cellulose ester type resin such as triethyl fluorene cellulose.

The thermoplastic resin forming the birefringent film can be used for the first and second thermoplastic resin films 10 and 20. For example, in the case of using a cellulose ester-based resin, a birefringent film can be obtained by the following method: using a cellulose ester-based resin having a phase difference adjustment function A method of forming a film by a compound, a method of applying a compound having a phase difference adjustment function on the surface of a cellulose ester-based resin film, or a method of uniaxially or biaxially stretching a cellulose ester-based resin. As the thermoplastic resin forming the birefringent film, other thermoplastic resins such as a polyvinyl alcohol resin, a polystyrene resin, a polyarylate resin, or a polyamide resin may be used.

The retardation film is used in combination of two or more for the purpose of controlling optical characteristics such as wide-band domain. Further, it is not limited to a film having optical anisotropy, and a retardation film may be a substantially zero-transfer film which is substantially optically isotropic. The retardation value of zero means the retardation film plane R _e and R _th retardation value in the thickness direction are both -15 to 15nm of the film. Here, the in-plane phase difference value R _e and the thickness direction phase difference value R _th are values at a wavelength of 590 nm.

The in-plane phase difference value R _e and the thickness direction phase difference value R _th are respectively defined by the following formula: R _e =(n _x -n _y )×d

R _th =[(n _x +n _y )/2-n _z ]×d

Wherein the refractive index n-line _x direction of the slow axis in the film plane (the x-axis direction), the fast axis direction (in the plane, with the y-axis direction orthogonal to the x-axis) indices of refraction of the surface film of _n-x , n _z is the refractive index of the film thickness direction (z-axis direction perpendicular to the film surface), and d is the thickness of the film.

The zero-retardment film can be used for the first and second thermoplastic resin films 10 and 20 and the thermoplastic resin described for the birefringent film. For example, a cellulose ester-based resin, a chain-like polyolefin resin, and a cyclic polymer can be used. A polyolefin resin such as an olefin resin, such as a thermoplastic resin film of a polyester resin such as polyethylene terephthalate. Among them, a cellulose ester resin or a polyolefin resin is suitable because the phase difference value is easy to control and easy to obtain.

Examples of other optical functional films (optical members) which may be included in the polarizing plate are a light collecting plate, a brightness enhancement film, a reflective layer (reflective film), a semi-transmissive reflective layer (semi-transflective reflective film), and a light diffusing layer. (light diffusion film) and the like. These are generally provided in the case where the polarizing plate is a polarizing plate disposed on the back side (backlight side) of the liquid crystal cell.

The light collecting plate is used for the purpose of controlling the optical path, etc., and may be a prism array sheet, a lens array sheet, a dot attached sheet, or the like.

The brightness enhancement film is used for the purpose of improving the brightness of a liquid crystal display device using a polarizing plate. Specifically, for example, a film in which the anisotropy of the refractive index of the plurality of laminated sheets is different from each other, a reflective polarizing separator designed to have an anisotropy in reflectance, and an oriented film of a cholesteric liquid crystal polymer Or a circularly polarizing separator or the like which supports the liquid crystal layer on the substrate film.

The reflective layer, the semi-transmissive reflective layer, and the light-diffusing layer are respectively provided to form the polarizing plate as a reflective, semi-transmissive, or diffusing optical member. The reflective polarizing plate is a type of liquid crystal display device for reflecting and reflecting incident light from the identification side. Since the light source such as a backlight can be omitted, the liquid crystal display device can be easily made thinner. The semi-transmissive polarizing plate is used for a reflective type in a bright place and a liquid crystal display device of a type which is displayed in a dark place by light from a backlight. In addition, a diffusing type of polarizing plate, A liquid crystal display device for imparting light diffusibility and suppressing display defects such as moiré. The reflective layer, the semi-transmissive reflective layer, and the light diffusing layer can be formed by a conventional method.

(5-2) Adhesive layer

The polarizing plate of the present invention may comprise an adhesive layer for attaching it to an image display element such as a liquid crystal cell or other optical member. In the polarizing plate of the first embodiment, the polarizing plate having the structure shown in Fig. 1 can be laminated on the outer surface of the polarizing film 30, and the polarizing plate having the structure shown in Fig. 2 can be laminated on the first thermoplastic resin film 10. Or the outer surface of the second thermoplastic resin film 20.

As the adhesive used in the pressure-sensitive adhesive layer, a (meth)acrylic resin, a polyoxymethylene resin, a polyester resin, a polyurethane resin, a polyether resin or the like can be used as the base polymer. Among them, a (meth)acrylic adhesive is suitable from the viewpoints of transparency, adhesion, reliability, weather resistance, heat resistance, and reworkability. Among the (meth)acrylic adhesives, useful base polymers: will have a methyl group, an ethyl group or a positive-. A (meth)acrylic acid alkyl group having an alkyl group having a carbon number of 20 or less, such as an iso- or a tri-butyl group, and a (meth)acrylic acid group having a functional group such as (meth)acrylic acid or hydroxyethyl (meth)acrylate The monomer is a (meth)acrylic resin having a weight average molecular weight of 100,000 or more, such that the glass transition temperature is preferably 25° C. or lower, more preferably 0° C. or lower.

The adhesive layer can be formed on the polarizing plate by, for example, dissolving or dispersing the adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare a solution of 10 to 40% by weight. A method of forming an adhesive layer on the surface of the polarizing plate or forming an adhesive layer on the release film subjected to the release treatment, and then moving the adhesive layer to the surface of the polarizing plate. The thickness of the adhesive layer is determined depending on the adhesion force, etc., and is preferably in the range of about 1 to 50 μm, preferably 2 to 40 μm.

The polarizing plate may include the above separator. The separator may be a film containing a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, or a polyester resin such as polyethylene terephthalate. Among them, a stretched film of polyethylene terephthalate is preferred.

In the adhesive layer, it can be formulated according to requirements: a filler containing glass fiber, glass beads, resin beads, metal powder or other inorganic powder; pigment; colorant; antioxidant; ultraviolet absorber; antistatic agent, and the like.

Examples of the antistatic agent include an ionic compound, conductive fine particles, and a conductive polymer. However, an ionic compound is suitable. The cationic component constituting the ionic compound may be an inorganic cation or an organic cation. Examples of the organic cations include a pyridinium cation, an imidazolium cation, an ammonium cation, a phosphonium cation, a phosphonium cation, a piperidinium cation, and a pyrrolidinium cation. Examples of the inorganic cation include lithium ion and potassium ion. On the other hand, the anion component constituting the ionic compound may be an inorganic anion or an anion. However, since an ionic compound excellent in antistatic property can be provided, an anion component containing a fluorine atom is preferred. Examples of the anion component containing a fluorine atom include a hexafluorophosphate anion [(PF ₆ -)], a bis(trifluoromethanesulfonyl)imide anion [(CF ₃ SO ₂ ) ₂ N-] anion, and a double (Fluoromethylsulfonyl) imine anion [(FSO ₂ ) ₂ N-] anion and the like.

(5-3) Protective film

The polarizing plate of the present invention may comprise a protective film for temporarily protecting the surface thereof (typically the surface of the thermoplastic resin film). The protective film is attached to the polarizing plate, for example, on an image display element or other optical member, and then peeled off together with the adhesive layer it has.

The protective film is composed of a base film and an adhesive layer laminated thereon. The above description is referenced regarding the adhesive layer. The resin constituting the base film may be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, or a poly A thermoplastic resin such as a carbonate resin. A polyester resin such as polyethylene terephthalate is preferred.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples and comparative examples, but the invention is not limited by the examples. In the example, the "%" and "parts" of the content or the amount used are based on weight unless otherwise specified.

(Manufacturing Example 1: Production of Protective Film)

The following resin [A] in a granular form and the following resin [B] in a granular form were put into an extruder at a weight ratio of 75:25 to obtain a (meth)acrylic resin composition. The obtained composition was melt-kneaded by heating to obtain a liquid melt kneaded product. The obtained melt kneaded product was continuously extruded from a T-die in the form of a film while being solidified using a cooling roll, thereby obtaining a thickness of 120 μm. A long (meth)acrylic resin film.

[A] "ALTUGLAS HT121" which is a methyl methacrylate resin manufactured by ARKEMA (glass transition temperature Tg: 124 ° C, weight average molecular weight Mw: 78200, number average molecular weight Mn: 41200, molecular weight dispersion Mw / Mn: 1.9 ), [B] methyl methacrylate resin (glass transition temperature Tg: 110 ° C, weight average molecular weight Mw: 162000, number average molecular weight Mn: 84500, molecular weight dispersion Mw / Mn: 1.9)

After the longitudinal stretching treatment was performed on the obtained (meth)acrylic resin film, a transverse stretching treatment (sequential biaxial stretching treatment) was further carried out to obtain a stretched protective film having a thickness of 40 μm. Further, regarding the stretching temperature, either the longitudinal stretching or the transverse stretching is a glass transition temperature of the (meth)acrylic resin film + 10 ° C, and the stretching ratio of the longitudinal stretching and the transverse stretching is It is 2.2 times and 2.0 times of the (meth)acrylic resin film, respectively.

<Examples 1 to 3, Comparative Example 1> (1) Modulation of a sclerosing adhesive composition

Each component shown in Table 1 was mixed in the parts by weight shown in Table 1, and the composition of the curable adhesive was prepared. The details of the components shown in Table 1 are as follows. The "radical polymerizable (meth)acrylic compound" described in Table 1 is a mixture of "DMAA", "DCPA", "A-DPH" and "UV3700B" described below, and the mixing ratio thereof is represented by a weight ratio. It is DMAA/DCPA/A-DPH/UV3700B=65/14/1/20.

DMAA: N,N-dimethyl methacrylate (available from KJ Chemicals Co., Ltd.), DCPA: dicyclopentyl acrylate (obtained by Hitachi Chemical Co., Ltd.), A-DPH: dipentaerythritol Acrylate (available from Shin-Nakamura Chemical Co., Ltd.), UV3700B: 2-functional urethane acrylate (obtained by Nippon Synthetic Chemical Co., Ltd.), photoradical polymerization initiator: 2-hydroxy-2 -Methyl-1-phenyl-propan-1-one ("DAROCUR 1173" obtained from Japan BASF Co., Ltd.), norbornene-based compound (I): methyl 5-northene-2-carboxylate ( Obtained by Tokyo Chemical Industry Co., Ltd.).

(2) Determination of storage elastic modulus of cured product of hardenable adhesive composition at 80 ° C

On one side of the cyclic polyolefin-based resin film having a thickness of 50 μm, a coater [bar coater; manufactured by First Chemical Co., Ltd.] was used to make the thickness of the curable adhesive composition after hardening to be about 30 μm. The coating was carried out in a manner, and a cyclic polyolefin-based resin film having a thickness of 50 μm was further laminated thereon. Then, the curable adhesive composition was cured by irradiating ultraviolet rays with "D valve" manufactured by Fusion UV Systems Co., Ltd. from the side of the one side of the cyclic polyolefin resin film so that the cumulative light amount was 3,000 mJ/cm ² . The double-layered layer of the cured film formed by curing the curable adhesive composition in a film form has a laminated film of a cyclic polyolefin-based resin film. The laminated film was cut into a size of 5 mm × 30 mm, and the cyclic polyolefin-based resin film was peeled off to obtain a cured film of a curable adhesive composition. The obtained cured film was held at a distance of 2 cm from the clamps using a dynamic viscoelasticity measuring device "DVA-220" manufactured by IT Keisoku Seigyo Co., Ltd., so that the long side thereof was in the direction of stretching. The frequency of shrinkage was set to 10 Hz, and the temperature increase rate was set to 3 ° C/min, and the storage elastic modulus at a temperature of 80 ° C was obtained. The results are presented in Table 1. The value of the storage elastic modulus at a temperature of 80 ° C is preferably higher, and the higher the temperature, the tendency to suppress the cracking of the polarizing film during the thermal shock test.

(3) Production of polarizing plate

The surface of the protective film produced in Production Example 1 was subjected to corona discharge treatment, and the hardening treatment was carried out by applying the above-mentioned (1) to the corona discharge treated surface so that the film thickness after curing was about 2.5 μm. Sexual binder composition. A polyvinyl alcohol-iodine-based polarizing film having a thickness of 25 μm was attached to the coated surface. Next, a corona discharge treatment was performed on the surface of a retardation film (trade name "ZEONOR", manufactured by Zeon Co., Ltd., Japan) having a thickness of 50 μm containing a cyclic polyolefin resin, and the surface was cured after the corona discharge treatment surface. The curable adhesive composition prepared in the above (1) (the same as the adhesive for bonding the protective film) was applied by a bar coater so that the film thickness was about 2.5 μm. On the coated surface, the polarizing film with the protective film obtained above was bonded to the polarizing film side to obtain a laminated body. From the side of the protective film of the laminate, the ultraviolet irradiation device with the conveyor belt is used so that the cumulative amount of light becomes 250 mJ/cm ² (UVB). [The illumination lamp is irradiated with "D valve" manufactured by Fusion UV Systems, Inc.] The hardenable adhesive composition is cured to prepare a polarizing plate.

(4) Evaluation of peeling force (adhesion force)

The surface of the protective film containing the (meth)acrylic resin in the obtained polarizing plate is subjected to a corona discharge treatment, and then a (meth)acrylic adhesive sheet is attached to the corona discharge treated surface to form an adhesive. Layer of polarizing plate. A test piece having a width of 25 mm and a length of about 200 mm was cut from the obtained polarizing plate with an adhesive layer, and the adhesive layer was attached to the soda glass. Then, the blade of the cutting blade was inserted between the polarizing film and the protective film, and peeled off from the end portion by 30 mm in the longitudinal direction, and the peeled portion was a universal tensile tester [AG-1 manufactured by Shimadzu Corporation). The gripper is held. The test piece in this state was held at a temperature of 23 ° C and a relative humidity of 55% in accordance with JIS K6854-2: 1999 "Adhesive - Peeling Strength Test Method - Part 2: 180 ° Peeling" to maintain the moving speed The 180° peel test was performed at 300 mm/min, and the average peel force at a length of 170 mm was obtained except for the 30 mm of the pliers portion. The results are presented in Table 1.

<Examples 4 to 13, Comparative Example 2> (5) Modulation of sclerosing adhesive composition

Each component shown in Table 2 or Table 3 was mixed in the weight part shown in Table 2 or Table 3, and the hardening adhesive composition was prepared. The details of the components shown in Tables 2 and 3 are as follows. The "radical polymerizable (meth)acrylic compound (I)" described in Table 2 is a mixture of "DMAA", "DCPA", "A-DPH" and "UV3700B" described below, and the mixing ratio thereof is The weight ratio is DMAA/DCPA/A-DPH/UV3700B=65/14/1/20, and the "radical polymerizable (meth)acrylic compound (II)" described in Table 3 is described below. HEAA".

DMAA: N,N-dimethyl methacrylamide (obtained by KJ Chemicals Co., Ltd.), DCPA: Dicyclopentyl acrylate (obtained by Hitachi Chemical Co., Ltd.), A-DPH: dipentaerythritol hexaacrylate (obtained by Shin-Nakamura Chemical Co., Ltd.), UV3700B: 2-functional uric acid Ester acrylate (available from Nippon Synthetic Chemical Co., Ltd.), HEAA: N-(2-hydroxyethyl) acrylamide (available from KJ Chemicals Co., Ltd.), photoradical polymerization initiator: 2-hydroxyl -2-methyl-1-phenyl-propan-1-one ("DAROCUR 1173" obtained from Japan BASF Co., Ltd.), norbornene-based compound (I): 5-northene-2-carboxylic acid A Ester (obtained from Tokyo Chemical Industry Co., Ltd.), norbornene compound (II): 5-northene-(N-2-hydroxyethyl)-2-carboxamide (obtained by ENAMINE Co., Ltd.) , decylene-based compound (III): 5-northene-2-methylamine (isomer mixture) (obtained from Tokyo Chemical Industry Co., Ltd.).

(6) Determination of storage modulus of cured product of hardenable adhesive composition at 80 ° C

With respect to the curable adhesive compositions obtained in Examples 4 to 6, the storage elastic modulus of the cured product at 80 ° C was measured in the same manner as in the above (1). The results are presented in Table 2.

(7) Production of polarizing plate (Examples 4 to 6)

The surface of the protective film produced in Production Example 1 was subjected to a corona discharge treatment, and the curable treatment surface (5) was applied to the corona discharge treated surface so that the film thickness after curing was about 2.5 μm. The composition of the agent. A polyvinyl alcohol-iodine-based polarizing film having a thickness of 25 μm was attached to the coated surface. Then, a corona discharge treatment was performed on the surface of a retardation film (trade name "ZEONOR", manufactured by Zeon Co., Ltd., Japan) having a thickness of 50 μm including a cyclic polyolefin resin, and the surface was hardened after the corona discharge treatment surface. The curable adhesive composition prepared in the above (5) (the same as the adhesive for bonding the protective film) was applied by a bar coater so that the film thickness was about 2.5 μm. On the coated surface, the polarizing film with the protective film obtained above was bonded to the polarizing film side to obtain a laminated body. From the side of the protective film of the laminate, the ultraviolet irradiation device with the conveyor belt is used so that the cumulative amount of light becomes 250 mJ/cm ² (UVB). [The illumination lamp is irradiated with "D valve" manufactured by Fusion UV Systems, Inc.] The hardenable adhesive composition is cured to prepare a polarizing plate.

(8) Production of polarizing plate (Examples 7 to 13, Comparative Example 2)

A corona discharge treatment was performed on the surface of a retardation film (trade name "ZEONOR", manufactured by Zeon Co., Ltd., Japan) having a thickness of 50 μm containing a cyclic polyolefin resin, and the film was cured on the surface of the corona discharge treatment. The curable adhesive composition prepared in the above (5) was applied by a bar coater so as to have a thickness of about 2.5 μm. A polyvinyl alcohol-iodine-based polarizing film having a thickness of 25 μm was attached to the coated surface. Next, a corona discharge treatment was applied to the surface of a protective film (trade name "Konica TAC KC8UX2MW"; manufactured by Konica Minolta Opto Co., Ltd.) having a thickness of 80 μm containing a cellulose ester resin, and the surface was cured after the corona discharge treatment surface. The curable adhesive composition prepared in the above (5) (the same as the adhesive for the retardation film bonding described above) was applied by a bar coater so that the film thickness was about 2.5 μm. On the coated surface, the retardation film obtained by the above-mentioned retardation film was bonded to the polarizing film side to obtain a laminate. From the retardation film side of the laminate, an ultraviolet irradiation device with a conveyor belt (the "lighting lamp system is "D valve" manufactured by Fusion UV Systems Co., Ltd.) is used so that the cumulative light amount is 250 mJ/cm ² (UVB). Ultraviolet rays harden the composition of the curable adhesive to prepare a polarizing plate.

(9) Evaluation of peeling force (adhesion force) (Examples 4 to 6)

The surface of the protective film containing the (meth)acrylic resin in the obtained polarizing plate is subjected to a corona discharge treatment, and then a (meth)acrylic adhesive sheet is attached to the corona discharge treated surface to form an adhesive. Layer of polarizing plate. A test piece having a width of 25 mm and a length of about 200 mm was cut from the obtained polarizing plate with an adhesive layer, and the adhesive layer was attached to the soda glass. The sample was stored in an environment of a temperature of 80 ° C and a relative humidity of 90% for 24 hours, and then stored overnight at a temperature of 23 ° C and a relative humidity of 55%. Then, the blade of the cutting blade was inserted between the polarizing film and the protective film, and peeled off from the end portion by 30 mm in the longitudinal direction, and the peeled portion was a universal tensile tester [AG-1 manufactured by Shimadzu Corporation). The gripper is held. The test piece in this state was placed in an environment of a temperature of 23 ° C and a relative humidity of 55% in accordance with JIS K6854-2: 1999 "Adhesive - Peeling Strength Test Method - Part 2: 180° peeling, a 180° peeling test was performed at a holding speed of 300 mm/min, and an average peeling force of 170 mm length was obtained except for the 30 mm of the pliers portion. The results are presented in Table 2. The value of the peeling force after storage at a temperature of 80 ° C and a relative humidity of 90% is preferably higher, and the higher the durability test in a hot and humid environment, the polarizing film and the thermoplastic resin film can be suppressed. The tendency to float or peel off.

(10) Evaluation of peeling force (adhesion force) (Examples 7 to 13, Comparative Example 2)

The surface of the retardation film of the obtained polarizing plate was subjected to a corona discharge treatment, and then a (meth)acrylic adhesive sheet was bonded to the corona discharge treated surface to form a polarizing plate with an adhesive layer. A test piece having a width of 25 mm and a length of about 200 mm was cut from the obtained polarizing plate with an adhesive layer, and the adhesive layer was attached to the soda glass. The sample was stored in an environment of a temperature of 80 ° C and a relative humidity of 90% for 24 hours, and then stored overnight at a temperature of 23 ° C and a relative humidity of 55%. Next, the blade of the cutting blade was inserted between the polarizing film and the retardation film, and peeled off from the end portion by 30 mm in the longitudinal direction, and the peeled portion was subjected to a universal tensile tester [AG-1 manufactured by Shimadzu Corporation). ] The gripper holds the grip. The test piece in this state was held at a temperature of 23 ° C and a relative humidity of 55% in accordance with JIS K6854-2: 1999 "Adhesive - Peeling Strength Test Method - Part 2: 180 ° Peeling" to maintain the moving speed The 180° peel test was performed at 300 mm/min, and the average peel force at a length of 170 mm was obtained except for the 30 mm of the pliers portion. The results are presented in Table 3. The value of the peeling force after storage at a temperature of 80 ° C and a relative humidity of 90% is preferably higher, and the higher the strain is inhibited in the endurance test in a hot and humid environment. The tendency of the polarizing film to float or peel off between the thermoplastic resin film.

10‧‧‧1st thermoplastic resin film

15‧‧‧1st adhesive layer

30‧‧‧ polarizing film

Claims (7)

A curable adhesive composition comprising: a radically polymerizable (meth)acrylic compound, a norbornene-based compound represented by the following formula (I), and a radical polymerization initiator; Wherein R ¹ , R ² , R ³ and R ⁴ are each independently a H atom or a substituent comprising at least one hetero atom selected from the group consisting of an O atom and an N atom; when R ¹ and R ³ are H atoms and R ^{When 2} and R ⁴ are the above substituents, R ² and R ⁴ may form a ring structure together with the two C atoms of the combined norbornene ring; the radical polymerization initiator is acted upon by an active energy ray The polymerization reaction of the radical polymerizable (meth)acrylic compound is caused by irradiation. The curable adhesive composition according to claim 1, which is a cured adhesive composition which is followed by a polarizing film and a thermoplastic resin film. The sclerosing adhesive composition according to claim 1 or 2, wherein at least one of R ¹ , R ² , R ³ and R ⁴ is the above-mentioned substituent, and the substituents are selected from the group consisting of - At least one of a group of C(=O)-, -OH, and -NH ₂ is a group. A polarizing plate comprising: a polarizing film; and a thermoplastic resin film laminated on at least one surface of the polarizing film via an adhesive layer; The adhesive layer is a cured layer of the curable adhesive composition according to claim 1 or 2. A polarizing plate comprising: a polarizing film; and a thermoplastic resin film laminated on at least one surface of the polarizing film via an adhesive layer; wherein the adhesive layer is a curable adhesive as described in claim 3 a hardened layer of the composition. The polarizing plate according to claim 4, wherein the thermoplastic resin film is selected from the group consisting of polyester resins, polycarbonate resins, polyolefin resins, (meth)acrylic resins, and cellulose esters. A resin composed of a group of resins. The polarizing plate according to claim 5, wherein the thermoplastic resin film is selected from the group consisting of polyester resins, polycarbonate resins, polyolefin resins, (meth)acrylic resins, and cellulose esters. A resin composed of a group of resins.