KR20180129652A - Adhesive composition and polarizing plate - Google Patents

Abstract

The present invention relates to an adhesive composition containing an oxazoline group-containing polymer (A) and a nitrogen-containing heterocyclic compound (B); and to a polarizing plate which includes a polarizer and a (meth)acrylate resin film stacked on the polarizer through an adhesive layer, wherein the adhesive layer is formed by using the adhesive composition. An objective of the present invention is to provide an adhesive composition with good adhesion.

Description

[0001] ADHESIVE COMPOSITION AND POLARIZING PLATE [0002]

The present invention relates to an adhesive composition and a polarizing plate using the same.

A polarizing plate widely used in an image display apparatus typified 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 polarizer. An adhesive is usually used for bonding the polarizer and the thermoplastic resin film. As the adhesive, an active energy ray curable adhesive and an aqueous adhesive are known (for example, JP-A-2009-008860).

An object of the present invention is to provide an adhesive composition which gives good adhesion and a polarizing plate using the same.

The present invention provides the following adhesive composition and a polarizing plate.

[1] An adhesive composition comprising an oxazoline group-containing polymer (A) and a nitrogen-containing heterocyclic compound (B).

[2] The adhesive composition according to [1], wherein the nitrogen-containing heterocyclic compound (B) is a compound having an aziridine structure.

[3] The adhesive composition according to [1] or [2], wherein the nitrogen-containing heterocyclic compound (B) is a compound having two or more nitrogen-containing heterocyclic structures in the molecule.

[4] The adhesive composition according to any one of [1] to [3], wherein the oxazoline group-containing polymer (A) is a water-soluble polymer.

[5] The adhesive composition according to any one of [1] to [4], wherein the oxazoline group-containing polymer (A) is a polymer having an oxazoline group in the side chain.

[6] The adhesive according to any one of [1] to [5], wherein the content of the nitrogen-containing heterocyclic compound (B) is 0.1 part by mass or more and 50 parts by mass or less based on 100 parts by mass of the oxazoline group- Composition.

[7] The adhesive composition according to any one of [1] to [6], further comprising a polyvinyl alcohol polymer (C).

[8] The adhesive composition according to [7], wherein the polyvinyl alcohol polymer (C) comprises at least one polymer selected from the group consisting of an acetoacetyl group-modified polyvinyl alcohol polymer and a carboxyl group-modified polyvinyl alcohol polymer.

[9] The adhesive composition according to [7] or [8], wherein the content of the polyvinyl alcohol polymer (C) is 1 part by mass or more and 300 parts by mass or less based on 100 parts by mass of the oxazoline group-containing polymer (A).

[10] The adhesive composition according to any one of [1] to [9], which is used for bonding a polarizer and a (meth) acrylic resin film.

[11] A polarizer,

(Meth) acrylic resin film laminated on the polarizer through an adhesive layer

/ RTI >

Wherein the adhesive layer is a layer formed from the adhesive composition according to any one of [1] to [10].

It is possible to provide an adhesive composition which gives good adhesion, and a polarizing plate using the same. The adhesive composition and the polarizing plate of the present invention not only exhibit good adhesion in a normal environment (for example, at a temperature of 23 DEG C and a relative humidity of 55%), but also exhibit good adhesion even after being placed in a humid environment (high temperature and high humidity environment) have.

1 is a schematic cross-sectional view showing an example of a layer structure of a polarizing plate according to the present invention.
2 is a schematic cross-sectional view showing another example of the layer structure of the polarizing plate related to the present invention.

≪ Adhesive composition >

The adhesive composition according to the present invention comprises an oxazoline group-containing polymer (A) and a nitrogen-containing heterocyclic compound (B). The adhesive composition may contain components other than the oxazoline group-containing polymer (A) and the nitrogen-nitrogen heterocycle compound (B), such as the polyvinyl alcohol-based polymer (C) described later.

The adhesive composition according to the present invention can exhibit good adhesion and can be used for producing a polarizing plate. More specifically, it is useful as an adhesive composition used for joining a polarizer and a thermoplastic resin film.

The adhesive composition according to the present invention not only exhibits good adhesion in a normal environment (for example, at a temperature of 23 DEG C and a relative humidity of 55%), but also exhibits good adhesion even after being placed under a humid environment (high temperature and high humidity environment) Do.

In the present specification, the compounds exemplified as the components included in the adhesive composition or exemplified as the components may be used alone or in combination of two or more, unless otherwise specified.

[1] The oxazoline group-containing polymer (A)

The oxazoline group-containing polymer (A) is preferably a polymer having an oxazoline group in the molecule and a polymer having an oxazoline group in the side chain. The main chain of the polymer is not particularly limited, but may be composed of, for example, at least one skeleton selected from a (meth) acryl skeleton, a styrene skeleton, and the like.

In the present specification, "(meth) acryl" means at least one kind selected from the group consisting of acrylic and methacrylic. Quot ;, " (meth) acryloyl ", and " (meth) acrylate ".

The oxazoline group-containing polymer (A) may have an oxazoline group in the side chain of the main chain.

A preferred example of the oxazoline group-containing polymer (A) is an oxazoline group-containing (meth) acryl-based polymer having a main chain comprising a (meth) acrylic skeleton and an oxazoline group in a side chain of the main chain.

When the oxazoline group-containing polymer (A) has an oxazoline group in the side chain, a linking group may be present between the main chain and the oxazoline group, but is preferably a polymer in which the main chain and the oxazoline group are directly bonded.

Examples of the oxazoline group include a 2-oxazoline group, a 3-oxazoline group and a 4-oxazoline group. The oxazoline group is preferably a 2-oxazoline group or the like.

The number average molecular weight of the oxazoline group-containing polymer (A) is preferably 5000 or more, and more preferably 10000 or more. When the number average molecular weight is within the above range, it tends to exhibit good adhesion. The number average molecular weight of the oxazoline group-containing polymer (A) is usually 100,000 or less.

The number average molecular weight of the oxazoline group-containing polymer (A) can be measured as a standard polystyrene conversion value by gel permeation chromatography (GPC).

The amount of the oxazoline group of the oxazoline group-containing polymer (A) (the number of mols of the oxazoline group per 1 g of the solid content of the oxazoline group-containing polymer (A)) is preferably 0.4 mmol / g · solids or more and 10 mmol / to be. If the amount of the oxazoline group is excessively high, good adhesion can not be obtained. If the amount of the oxazoline group is less than the above range, the water resistance of the adhesive layer may be deteriorated. From this point of view, the amount of the oxazoline group in the oxazoline group-containing polymer (A) is more preferably 3 mmol / g · solids or more and 9 mmol / g · solids or less.

The oxazoline group-containing polymer (A) may be a water-based polymer, that is, a water-soluble polymer or a water-dispersible polymer (a water-soluble polymer) when the adhesive composition is an aqueous adhesive composition (an adhesive in which the adhesive component is dissolved in water or dispersed in water) . From the viewpoint of optical properties of the adhesive layer, the oxazoline group-containing polymer (A) is preferably a water-soluble polymer.

As the oxazoline group-containing polymer (A), a commercially available product may be used. Specific examples thereof include oxazoline group-containing acrylic polymers such as Epochros WS-300, Epochros WS-500 and Epocross WS-700 (all trade names) manufactured by Nippon Shokubai Co., And oxazoline group-containing acrylic / styrene polymers such as Epocross K-1000 series manufactured by Nippon Shokubai Co., Ltd., Epocross K-2000 series, and Epocross RPS series (all trade names).

The oxazoline group-containing polymer (A) may be used in combination of two or more.

From the viewpoints of adhesion, optical properties and water resistance, oxazoline group-containing acrylic polymers such as Epocross WS-300 and Epocross WS-700 are preferable.

[2] The nitrogen-containing heterocyclic compound (B)

The nitrogen-containing heterocyclic compound (B) is a compound having a cyclic structure (nitrogen-containing heterocyclic structure) in which at least one of the carbon atoms constituting the ring of the cyclic hydrocarbon structure is substituted with a nitrogen atom. The nitrogen-containing heterocyclic structure may be a monocyclic ring or a polycyclic ring such as a condensed ring.

The nitrogen-containing heterocyclic compound (B) may have only one nitrogen-containing heterocyclic structure in the molecule, or two or three or more nitrogen-containing heterocyclic compounds may be contained in the molecule. In the case where the nitrogen-containing heterocyclic compound (B) has a plurality of nitrogen-containing heterocyclic structures in the molecule, these nitrogen-nitrogen heterocyclic structures may have the same structure or different structures.

When the nitrogen-containing heterocyclic compound (B) has a plurality of nitrogen-containing heterocyclic structures in the molecule, these plural nitrogen-nitrogen heterocyclic structures preferably have the same structure.

Examples of the nitrogen-containing heterocyclic structure include aziridine structure, azirine structure, azetidine structure, 1,2-oxathetidine structure, 1,3-oxathetidine structure, 1,2-thiazetidine structure, 1 , A 3-thiazetidine structure, a 1,2-dihydrorazate structure, a 1,3-diazet structure, a pyrrolidine structure, a pyrroline structure, an imidazolidine structure, an imidazoline structure, a pyrazolidine structure, An isoxazole structure, an isoxazole structure, a thiazole structure, a thiadiazole structure, an isothiazole structure, an isothiazole structure, an isothiazole structure, an isothiazole structure, -Triazole structure, 1,2,4-triazole structure, tetrazole structure, 1,3,4-oxadiazole structure, furazan structure, pyridine structure, pyridazine structure, pyrimidine structure, pyrazine structure, A monocyclic structure such as a piperidine structure, a piperidine structure, a morpholine structure, a thiazine structure, a piperidone structure, a triazine structure, an oxazine structure, and a tetrazine structure;

Polycyclic structures such as benzoimidazole, benzotriazole, benzoxazole, benzothiazole, quinolizine, indolizine, indole, quinoline, isoquinoline, benzotriazine, tetrazene, and purine;

.

The nitrogen-containing heterocyclic structure may have one or more substituents bonded to the ring structure. Examples of the substituent include a hydrocarbon group having about 1 to 12 carbon atoms (e.g., an alkyl group).

The nitrogen-containing heterocyclic compound (B) is preferably a compound having a structure capable of forming a crosslinking structure with the oxazoline group-containing polymer (A) or a thermoplastic resin film (protective film, etc.) described later. When the nitrogen-containing heterocyclic compound (B) can form a crosslinked structure with the oxazoline group-containing polymer (A) or a thermoplastic resin film described later, good adhesion can be exhibited.

The structure capable of forming a crosslinked structure with the oxazoline group-containing polymer (A) or a thermoplastic resin film described later (hereinafter sometimes referred to as " crosslinkable structure (1) ") is not particularly limited. The crosslinkable structure (1) may be a structure capable of forming a crosslinking structure with a functional group such as a hydroxyl group or a carboxyl group, or may be a nitrogen-containing heterocyclic structure itself. Examples of such a nitrogen-containing heterocyclic structure include an oxazoline ring and an aziridine ring, and from the viewpoint of adhesion, an aziridine ring is preferable.

The nitrogen-containing heterocyclic compound (B) preferably has two or more crosslinkable structures (1), more preferably two or more nitrogen-containing heterocyclic structures as the crosslinkable structure (1), more preferably an aziridine ring More preferably two or more.

The nitrogen-containing heterocyclic compound (B) is usually a non-polymeric compound. The molecular weight of the nitrogen-containing heterocyclic compound (B) is usually 41 or more and 2000 or less. The molecular weight of the nitrogen-containing heterocyclic compound (B) may be 1500 or less, and may be 1000 or less.

The pH of the 1.0% by mass aqueous solution of the nitrogen-containing heterocyclic compound (B) is preferably 4 or more and 13 or less, more preferably 6 or more and 13 or less, at 25 占 폚. When the pH of the 1.0% by mass aqueous solution of the nitrogen-containing heterocyclic compound (B) is less than 4, there is a possibility of lowering the reactivity of the oxazoline group-containing polymer (A) When the pH of the aqueous solution is more than 13, there is a possibility that the pot life of the adhesive composition is shortened.

As a method for measuring the pH in the 1.0 mass% aqueous solution of the nitrogen-containing heterocyclic compound (B), the same method as the pH measurement of the pressure-sensitive adhesive composition can be mentioned.

The content of the nitrogen-containing heterocyclic compound (B) in the adhesive composition is usually 0.1 part by mass or more and 50 parts by mass or less, preferably 0.2 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the oxazoline group- Parts by mass or less, and more preferably 0.5 parts by mass or more and 20 parts by mass or less. When the content of the nitrogen-containing heterocyclic compound (B) is within this range, there is a tendency that good adhesiveness tends to be exhibited.

The nitrogen-containing heterocyclic compound (B) preferably has a crosslinkable structure (1) at the terminal thereof, more preferably an aziridine ring at the terminal thereof, more preferably a compound represented by the formula (B1).

[In the formula (B1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

X ¹ and X ² each independently represent -O- or -NH-.

L ¹ and L ³ each independently represent a single bond or an alkanediyl group having 1 to 6 carbon atoms.

L ² represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and -CH ₂ - contained in the hydrocarbon group may be substituted with -O- or -CO-.]

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, , n-pentyl group, n-hexyl group and the like.

Examples of the alkanediyl group having 1 to 6 carbon atoms represented by L ¹ and L ³ include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, Di-1-yl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2-diyl group, Methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane- .

Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by L ² include an alkanediyl group having 1 to 20 carbon atoms and a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the alkanediyl group having 1 to 20 carbon atoms represented by L ² include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane- -1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane- Diyl group, a dodecane-1,12-diyl group, an ethane-1,1-diyl group, a propane-1,1-diyl group, a propane- Methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4 -Diethyl group, and 2-ethyl-2-pentylpropane-1,3-diyl group.

Examples of the divalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by L ² include a phenylene group, a naphthalenediyl group, a biphenyldiyl group, and a diphenylmethanediyl group.

The divalent hydrocarbon group having 1 to 20 carbon atoms represented by L ² is preferably an alkanediyl group having 1 to 10 carbon atoms and a divalent aromatic hydrocarbon group having 6 to 14 carbon atoms.

Examples of the substituent which may have a divalent hydrocarbon group having 1 to 20 carbon atoms represented by L ² include a hydroxyl group and an aziridine group.

The compound represented by the formula (B1) is preferably a compound represented by the formula (B2).

In the formula (B2), R ¹ , R ² , R ³ , R ⁴ , L ¹ , L ³ , X ¹ and X ² have the same meanings as defined above.

L ²¹ represents an alkanediyl group having 1 to 10 carbon atoms which may have a hydroxyl group.

L ²² represents an alkanediyl group having 1 to 10 carbon atoms, and -CH ₂ - contained in the alkanediyl group may be substituted with -O- or -CO-.

R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁵ and R ⁶ include the same alkyl groups having 1 to 6 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ .

Examples of the alkanediyl group having 1 to 10 carbon atoms represented by L ²¹ and L ²² include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, A nonyl group, a nonyl group, a heptyl group, a heptyl group, a heptyl group, a heptyl group, a heptyl group, a heptyl group, a heptyl group, , 1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane- -Diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl and the like.

-CH ₂ - included in the alkanediyl group having 1 to 10 carbon atoms represented by L ²² may be substituted with -O- or -CO-, * -L ²³ -O-CO-L ²⁴ - (* , represents the combined number (手) of L ^21, L ²³ and L ²⁴ are preferably each independently a group represented by represents an alkanediyl group having 1 to 4 carbon atoms).

As the compound represented by the formula (B1), for example, the following compounds can be mentioned.

As the nitrogen-containing heterocyclic compound (B), diphenylmethane-4,4'-bis (1-aziridine carboxamide), toluene-2,4-bis (1-aziridine carboxamide), triethylene melamine , Isophthaloylbis-1- (2-methyl aziridine), tris-1-aziridinylphosphine oxide, hexamethylene-1,6-bis (1-aziridine carboxamide), trimethylolpropane tris- aziridinyl propionate, tetramethylol methane tris-? - aziridinyl propionate, piperidine, 4-picoline, 3,5-diethylpyridine, 1,4-bis Propyl) piperazine, a compound represented by formula (B1-1) to a compound represented by formula (B1-4).

Specific examples of the nitrogen-containing heterocyclic compound (B) include commercially available products such as Chemitite PZ-33 and Chemitite DZ-22E (all trade names) manufactured by Nippon Shokubai Co., Ltd.; Aziridine compounds such as CROSSLINKER CL-422, CROSSLINKER CL-427 and CROSSLINKER CL-467 (all trade names) manufactured by MENADIONA. Particularly, from the viewpoint of adhesion, CROSSLINKER CL-427 and CROSSLINKER CL-467 are preferable.

[3] Polyvinyl alcohol polymer (C)

The adhesive composition may comprise a polyvinyl alcohol polymer (C). By containing the polyvinyl alcohol polymer (C) in the adhesive composition, an adhesive composition exhibiting higher adhesion can be obtained.

Examples of the polyvinyl alcohol polymer (C) include polyvinyl alcohol polymers such as partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, and modified polyvinyl alcohol polymers which are modifications of polyvinyl alcohol polymers.

Examples of the modified polyvinyl alcohol polymer include carboxyl group denatured polyvinyl alcohol, acetoacetyl group denatured polyvinyl alcohol, methylol group denatured polyvinyl alcohol, amino group denatured polyvinyl alcohol, and carbonyl denatured polyvinyl alcohol.

The polyvinyl alcohol polymer (C) is not limited to a vinyl alcohol homopolymer (fully saponified polyvinyl alcohol or partially saponified polyvinyl alcohol) obtained by saponifying a polyvinyl acetate which is a homopolymer of vinyl acetate, And other monomers copolymerizable therewith may be subjected to a saponification treatment to obtain a polyvinyl alcohol copolymer.

Other monomers copolymerizable with vinyl acetate include (meth) acrylamides having unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and ammonium groups.

The polyvinyl alcohol polymer (C) is usually a polymer containing 50 mol% or more of a structural unit (-CH ₂ -CH (OH) -) of vinyl alcohol.

The degree of saponification of the polyvinyl alcohol polymer (C) is usually from 85 mol% to 100 mol%, and preferably 90 mol% or more (for example, 95 mol% or more).

The degree of saponification of the polyvinyl alcohol polymer (C) can be measured according to JIS K 6726: 1994.

From the viewpoint of improving the adhesion, the polyvinyl alcohol polymer (C) preferably contains a modified polyvinyl alcohol polymer and is preferably selected from the group consisting of an acetoacetyl group-modified polyvinyl alcohol polymer and a carboxyl group-modified polyvinyl alcohol polymer It is more preferable to include at least one polymer.

The modified polyvinyl alcohol polymer means a polyvinyl alcohol polymer in which a part of the structural units of the vinyl alcohol is substituted with a functional group such as an acetoacetyl group or a carboxyl group.

The modifying amount of the modified polyvinyl alcohol polymer is not particularly limited as long as it is 0.1 mol% or more. The modification amount of 0.1 mol% or more is also advantageous in increasing the water resistance of the adhesive layer. The modified amount is preferably from 0.1 mol% to 40 mol%, from the viewpoints of adhesion and water resistance.

The amount of modification can be measured, for example, by ¹ H-NMR.

From the viewpoint of improving the adhesion, the average degree of polymerization of the polyvinyl alcohol polymer (C) is preferably 100 or more and 3,000 or less, more preferably 500 or more and 3,000 or less.

The average polymerization degree of the polyvinyl alcohol polymer (C) can be measured according to JIS K 6726: 1994.

The content of the polyvinyl alcohol polymer (C) in the adhesive composition is usually 1 part by mass or more and 300 parts by mass or less, preferably 5 parts by mass or more and 250 parts by mass or less, based on 100 parts by mass of the oxazoline group- By mass or less, and more preferably 10 parts by mass or more and 200 parts by mass or less. If the content of the polyvinyl alcohol polymer (C) is within this range, the effect of improving the adhesion tends to be easily exhibited.

[4] Other ingredients

The adhesive composition may contain other components other than the oxazoline group-containing polymer (A), the nitrogen-nitrogen heterocycle compound (B) and the polyvinyl alcohol-based polymer (C).

Other components include curing components such as polyvalent aldehyde, melamine compound, zirconia compound, zinc compound, glyoxal, glyoxal derivative and water-soluble epoxy resin, and crosslinking agent; A coupling agent, a tackifier, an antioxidant, an ultraviolet absorber, a heat stabilizer, and a hydrolysis inhibitor.

The adhesive composition preferably includes a solvent. Examples of the solvent include water, organic solvents, and mixtures thereof. The solvent preferably includes water, but water and a water-soluble organic solvent may be used in combination. Examples of the organic solvent include ethanol, 1-methoxy-2-propanol, and the like.

The solid content concentration of the adhesive composition is usually 0.5% by mass or more and 20% by mass or less, preferably 1% by mass or more and 15% by mass or less.

The solid content concentration refers to the total concentration of components other than the solvent contained in the adhesive composition.

The concentration of the oxazoline group-containing polymer (A) in the adhesive composition is preferably 0.1 mass% or more and 30 mass% or less, more preferably 0.5 mass% or more and 20 mass% or less, further preferably 1 mass% or more and 15 mass% or less Is more preferable. When the concentration of the oxazoline group-containing polymer (A) is less than the lower limit described above, it is difficult to obtain sufficient adhesiveness. If the concentration exceeds the upper limit, the viscosity of the adhesive composition increases and problems such as clogging of the pipe occur There is a possibility.

The adhesive composition is preferably an aqueous adhesive. That is, the adhesive composition is a solution obtained by dissolving components such as an oxazoline group-containing polymer (A), a nitrogen-nitrogen heterocycle compound (B) and a polyvinyl alcohol polymer (C) in a solvent containing water, (For example, an emulsion) in which a component such as an oxazoline group-containing polymer (A), a nitrogen-nitrogen heterocycle compound (B) and a polyvinyl alcohol polymer (C) are dispersed in a solvent containing the above-

The viscosity of the adhesive composition at 25 ° C is preferably 50 mPa · sec or less, more preferably 2 mPa · sec or more and 30 mPa · sec or less, still more preferably 4 mPa · sec or more and 20 mPa · sec or less. If the viscosity at 25 ° C is more than 50 mPa · sec, it is difficult to uniformly coat the coating, and there is a possibility that coating unevenness may occur, and problems such as clogging of the pipe may occur.

The viscosity of the adhesive composition at 25 캜 can be measured by an E-type viscometer.

The pH of the adhesive composition at 25 DEG C is preferably 3 or more and 10 or less, more preferably 4 or more and 9 or less. When the pH of the adhesive composition is less than 3, there is a possibility that the water resistance of the adhesive layer may not be sufficiently exhibited. If the pH of the adhesive composition exceeds 10, the pot life of the adhesive composition may be shortened.

The method for measuring the pH of the adhesive composition is as described in the following [Examples].

<Polarizer>

The adhesive composition according to the present invention can be suitably used as an adhesive for bonding a polarizer constituting a polarizing plate and a thermoplastic resin film such as a protective film laminated thereon.

The polarizing plate related to the present invention comprises a polarizer and a thermoplastic resin film laminated on at least one side of the polarizer through an adhesive layer formed from the adhesive composition according to the present invention.

In the polarizing plate according to one preferred embodiment, the adhesive layer is a cured layer of the adhesive composition according to the present invention.

In the polarizing plate related to the present invention, since the polarizer and the thermoplastic resin film are bonded using the adhesive composition related to the present invention, the adhesion between the polarizer and the thermoplastic resin film can be improved.

The polarizing plate according to the present invention not only has good adhesion in a normal environment (for example, at a temperature of 23 DEG C and a relative humidity of 55%), but also can exhibit good adhesion even after being placed in a humid environment (high temperature and high humidity environment) .

[1] Configuration of polarizer

Examples of the layer structure of the polarizing plate related to the present invention are shown in Fig. 1 and Fig.

1, the polarizing plate according to the present invention includes a polarizer 30 and a first thermoplastic resin film 10 laminated on one surface of the polarizer 30 through a first adhesive layer 15 have.

2, the polarizer according to the present invention comprises a polarizer 30, a first thermoplastic resin film 10 laminated on one side of the polarizer 30 through a first adhesive layer 15, 30 and the second thermoplastic resin film 20 laminated and bonded to the other surface of the first thermoplastic resin film 20 through the second adhesive layer 25.

In the case where the polarizing plate has the first adhesive layer 15 and the second adhesive layer 25, either one may be formed from the adhesive composition related to the present invention, and both of the adhesive layers may be formed from the adhesive composition related to the present invention It may be.

In the case where both adhesive layers are formed from the adhesive composition related to the present invention, these adhesive compositions may be the same composition or different compositions.

The polarizing plate related to the present invention may include layers (or films) other than those described above. Other layers include, for example, a pressure-sensitive adhesive layer laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20 and / or the polarizer 30; A separate film (also referred to as a &quot; release film &quot;) laminated on the outer surface of the pressure-sensitive adhesive layer; A protective film (also referred to as a &quot; surface protective film &quot;) laminated on the outer surfaces of the first thermoplastic resin film 10, the second thermoplastic resin film 20 and / or the polarizer 30; An optical functional film (or layer) laminated on the outer surfaces of the first thermoplastic resin film 10, the second thermoplastic resin film 20 and / or the polarizer 30 through an adhesive layer or a pressure-sensitive adhesive layer.

[2] polarizers

The polarizer 30 is a film having a function of selectively transmitting linearly polarized light in any one direction from natural light. For example, a dye-based polarizer in which a dichroic dye as a dichroic dye is adsorbed and oriented on an iodine-based polarizer or a polyvinyl alcohol-based resin film in which iodine as a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, Coated dichroic dyes, and orientation-fixed dichroic dyes. These polarizers are called absorption type polarizers because they selectively transmit linear polarized light in one direction from natural light and absorb linear polarized light in the other direction.

The polarizer 30 is not limited to the absorptive polarizer but may be a reflective polarizer that selectively transmits one directional linear polarized light from natural light and reflects another linear polarized light in one direction or a reflective polarizer that reflects another linear polarized light in one direction Although it may be a polarizer, an absorptive polarizer is preferable in view of excellent visibility. Among them, a polyvinyl alcohol polarizer composed of a polyvinyl alcohol resin is more preferable, and a polyvinyl alcohol polarizer in which a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin film And a polyvinyl alcohol polarizer in which iodine is adsorbed and oriented on a polyvinyl alcohol-based resin film is particularly preferable.

As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol polarizer, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include a copolymer of vinyl acetate, which is a homopolymer of vinyl acetate, and other monomers copolymerizable with vinyl acetate. Other monomers copolymerizable with vinyl acetate include (meth) acrylamides having unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and ammonium groups.

The degree of saponification of the polyvinyl alcohol resin is usually 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. The polyvinyl alcohol resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehyde may be used. The average degree of polymerization of the polyvinyl alcohol resin is usually from 1,000 to 10,000, and preferably from 1,500 to 5,000. The average polymerization degree of the polyvinyl alcohol resin can be obtained according to JIS K 6726: 1994.

Such a polyvinyl alcohol resin film is used as the original film of the polarizer 30. The method of forming the polyvinyl alcohol resin is not particularly limited, and a known method is employed. The thickness of the polyvinyl alcohol original film is, for example, 150 占 퐉 or less, preferably 100 占 퐉 or less (e.g., 50 占 퐉 or less) and 5 占 퐉 or more.

The polarizer (30) comprises a step of uniaxially stretching a polyvinyl alcohol resin film; Dyeing a polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye; A step of treating (crosslinking) a polyvinyl alcohol resin film adsorbed with a dichroic dye with an aqueous solution of boric acid; And a step of washing with water after treatment with an aqueous boric acid solution.

The uniaxial stretching of the polyvinyl alcohol resin film can be performed before, simultaneously with, or after dyeing the dichroic dye. In the case where uniaxial stretching is carried out after dyeing, this uniaxial stretching may be carried out before the boric acid treatment or during the boric acid treatment. In addition, uniaxial stretching may be performed in these plural stages.

In the uniaxial stretching, the uniaxial stretching may be performed between rolls different in the main speed, or may be uniaxially stretched using a heat roll. The uniaxial stretching may be dry stretching in which stretching is performed in the air or wet stretching in which a polyvinyl alcohol resin film is stretched by using a solvent such as water. The draw ratio is usually 3 times or more and 8 times or less.

As a method for dyeing a polyvinyl alcohol resin film with a dichroic dye, for example, there is a method of immersing the film in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine or a dichroic organic dye is used. It is preferable that the polyvinyl alcohol resin film is subjected to immersion treatment in water before the dyeing treatment.

Examples of the dyeing treatment method with iodine include a method of immersing a polyvinyl alcohol resin film in an aqueous solution containing iodine and potassium iodide. The content of iodine in the aqueous solution may be 0.01 part by mass or more and 1 part by mass or less per 100 parts by mass of water. The content of potassium iodide may be 0.5 parts by mass or more and 20 parts by mass or less per 100 parts by mass of water. The temperature of the aqueous solution may be 20 占 폚 or higher and 40 占 폚 or lower.

On the other hand, as a dyeing treatment method using a dichroic organic dye, a method of immersing a polyvinyl alcohol resin film in an aqueous solution containing a dichroic organic dye can be given. The aqueous solution containing the dichroic organic dye may contain an inorganic salt such as sodium sulfate as a dyeing aid. The content of the dichroic organic dye in the aqueous solution may be 1 x ^10-4 mass parts or more and 10 mass parts or less per 100 mass parts of water. The temperature of the aqueous solution may be 20 ° C or higher and 80 ° C or lower.

Examples of the method for treating boric acid after dyeing with a dichroic dye include a method in which a dyed polyvinyl alcohol resin film is dipped in an aqueous solution containing boric acid. When iodine is used as the dichroic dye, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The amount of boric acid in the aqueous solution containing boric acid may be 2 parts by mass or more and 15 parts by mass or less per 100 parts by mass of water. The amount of potassium iodide in the aqueous solution may be 0.1 part by mass or more and 20 parts by mass or less per 100 parts by mass of water. The temperature of the aqueous solution may be 50 ° C or higher, for example, 50 ° C or higher and 85 ° C or lower.

The polyvinyl alcohol resin film after boric acid treatment is usually subjected to water washing treatment. The water washing treatment can be carried out, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of the water in the water washing treatment is generally 5 ° C or higher and 40 ° C or lower. After washing with water, drying treatment is carried out to obtain a polarizer 30.

The drying treatment can be performed using a hot-air dryer or a far-infrared heater. A polarizing plate can be obtained by bonding a thermoplastic resin film as a protective film or the like to one side or both sides of the polarizer 30 using an adhesive composition.

As another example of the manufacturing method of the polarizer 30, there can be mentioned, for example, the methods described in Japanese Patent Laid-Open Nos. 2000-338329 and 2012-159778. In this method, a solution containing a polyvinyl alcohol-based resin is applied to the surface of a base film to form a resin layer, and then a laminated film comprising a base film and a resin layer is stretched, followed by dyeing treatment and crosslinking treatment Thereby forming a polarizer layer (polarizer layer) from the resin layer. The polarizing laminated film comprising the base film and the polarizer layer can be obtained by bonding a thermoplastic resin film as a protective film or the like to the polarizer layer surface and then peeling off the base film to obtain a polarizing plate having the structure shown in Fig. When the thermoplastic resin film is further bonded to the polarizer layer surface exposed by the peeling of the base film, a polarizing plate having the structure shown in Fig. 2 is obtained.

The thickness of the polarizer 30 can be 40 占 퐉 or less, preferably 30 占 퐉 or less (e.g. 20 占 퐉 or less, further 15 占 퐉 or less, further 10 占 퐉 or less or 8 占 퐉 or less). According to the method described in JP-A-2000-338329 or JP-A-2012-159778, a thin film polarizer 30 can be manufactured more easily, and the thickness of the polarizer 30 is set to 20 Mu m or less, more preferably 15 mu m or less, further more 10 mu m or less or 8 mu m or less. The thickness of the polarizer 30 is usually 2 占 퐉 or more. Reducing the thickness of the polarizer 30 is advantageous for reducing the thickness of the polarizing plate and hence the image display apparatus.

[3] thermoplastic resin films

Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be formed of a thermoplastic resin having light transmittance (preferably optically transparent) such as a chain type polyolefin resin (polypropylene type resin, etc.) Polyolefin resins such as polyolefin resins (norbornene resins and the like); Cellulose ester-based resins such as triacetylcellulose and diacetylcellulose; Polyester resins such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; Polycarbonate resin; (Meth) acrylic resins; Or a mixture or copolymer thereof, or the like.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be either unstretched films or monoaxially or biaxially stretched films, respectively. The biaxial stretching may be simultaneous biaxial stretching in which stretching is performed simultaneously in two stretching directions, or sequential biaxial stretching in which stretching in a first direction is followed by stretching in a second direction different from the biaxial stretching.

The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may be a protective film that protects the polarizer 30 or may be a protective film having an optical function such as a retardation film have.

The retardation film is an optical functional film used for the purpose of compensating a retardation by a liquid crystal cell serving as an image display element. For example, a retardation film having an arbitrary retardation value can be obtained by stretching (uniaxial stretching or biaxial stretching) a film made of the thermoplastic resin, or forming a liquid crystal layer or the like on the thermoplastic resin film.

Examples of the chain-like polyolefin-based resin include a homopolymer of a chain-like olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more kinds of chain-like olefins.

The cyclic polyolefin-based resin is a generic name of a resin containing, as a polymerization unit, a cyclic olefin represented by norbornene or tetracyclododecene (also called dimethano-octahydronaphthalene) or a derivative thereof. Examples of the cyclic polyolefin-based resin include a ring-opened (co) polymer of a cyclic olefin and a hydrogenated product thereof, an addition polymer of a cyclic olefin, a copolymer of a cyclic olefin and a chain olefin such as ethylene or propylene or an aromatic compound having a vinyl group, And a modified (co) polymer modified with an unsaturated carboxylic acid or a derivative thereof.

Among them, a norbornene resin using a norbornene monomer such as norbornene or a polycyclic norbornene monomer is preferably used as the cyclic olefin.

The cellulose ester-based resin may be a mixed ester in which at least a part of the hydroxyl groups in cellulose are converted into acetic acid ester, part of which is converted into acetic ester and partly esterified with another acid. The cellulose ester-based resin is preferably an acetylcellulose-based resin.

Examples of the acetylcellulose-based resin include triacetylcellulose, diacetylcellulose, cellulose acetate propionate, and cellulose acetate butyrate.

The polyester-based resin is a resin other than the cellulose ester-based resin having an ester bond, and is generally composed of a polycondensation product of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol.

Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, polycyclohexane dimethyl Phthalate and the like.

Among them, polyethylene terephthalate is preferably used from the viewpoints of mechanical properties, solvent resistance, scratch resistance, cost and the like. Polyethylene terephthalate refers to a resin in which 80 mol% or more of the repeating units are composed of ethylene terephthalate, and may contain a structural unit derived from another copolymerization component.

Other copolymerization components include a dicarboxylic acid component and a diol component.

Examples of the dicarboxylic acid component include isophthalic acid, 4,4'-dicarboxy diphenyl, 4,4'-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane, adipic acid, Sulfoisophthalic acid, and 1,4-dicarboxycyclohexane.

Examples of the diol component include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

The dicarboxylic acid component and the diol component may be used in combination of two or more kinds, if necessary.

It is also possible to use a hydroxycarboxylic acid such as p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid or? -Hydroxyethoxybenzoic acid in combination with the dicarboxylic acid component or the diol component.

As a different copolymerization component, a small amount of a dicarboxylic acid component and / or a diol component having an amide bond, a urethane bond, an ether bond, a carbonate bond or the like may be used.

The polycarbonate resin is a polyester formed from carbonic acid and glycol or bisphenol. Among them, an aromatic polycarbonate having a diphenylalkane in a molecular chain is preferably used from the viewpoints of heat resistance, weather resistance and acid resistance.

Examples of the polycarbonate include 2,2-bis (4-hydroxyphenyl) propane (also called bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, And polycarbonates derived from bisphenols such as cyclohexane, 1,1-bis (4-hydroxyphenyl) isobutane, and 1,1-bis (4-hydroxyphenyl) ethane.

The (meth) acrylic resin may be, for example, a polymer containing methacrylic acid ester as a main monomer (containing 50 mass% or more), and is preferably a copolymer in which methacrylic acid ester and other copolymerizable components are copolymerized.

In one preferred embodiment, the (meth) acrylic resin contains methyl methacrylate as a copolymerization component, or includes methyl methacrylate and methyl acrylate.

Examples of the copolymerization component other than methyl acrylate include ethyl methacrylate, n-, i- or t-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid 2 Methacrylic acid esters other than methyl methacrylate such as ethylhexyl and 2-hydroxyethyl methacrylate;

Acrylic acid esters such as ethyl acrylate, n-, i- or t-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate;

(Meth) acrylates such as methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, n- Hydroxyalkyl acrylate esters;

Unsaturated acids such as methacrylic acid and acrylic acid;

Halogenated styrenes such as chlorostyrene and bromostyrene;

Substituted styrenes such as vinyltoluene and? -Methylstyrene;

Unsaturated nitriles such as acrylonitrile and methacrylonitrile;

Unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride;

Unsaturated imides such as phenylmaleimide and cyclohexylmaleimide;

And the like.

The other monofunctional monomer may be used alone, or two or more monofunctional monomers may be used in combination.

A polyfunctional monomer may be used as the other copolymerization component.

Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) Ethylene glycol such as di (meth) acrylate and tetradecaethylene glycol di (meth) acrylate, or ester oligomers obtained by esterifying both terminal hydroxyl groups of the oligomer with (meth) acrylic acid;

Esterification of both terminal hydroxyl groups of propylene glycol or an oligomer thereof with (meth) acrylic acid;

(Meth) acrylic acid ester of a hydroxyl group of a dihydric alcohol such as neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate and butanediol di (meth) acrylate;

Bisphenol A, alkylene oxide adducts of bisphenol A, or both terminal hydroxyl groups of the halogen substituents thereof esterified with (meth) acrylic acid;

(Meth) acrylic acid, and epoxy groups of glycidyl (meth) acrylate are ring-opening added to these terminal hydroxyl groups;

A dibasic acid such as succinic acid, adipic acid, terephthalic acid, phthalic acid, and halogen substituents thereof, or an alkylene oxide adduct thereof, and the like, in which an epoxy group of glycidyl (meth) acrylate is ring-

Aryl (meth) acrylate; Aromatic divinyl compounds such as divinylbenzene;

And the like.

Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate and neopentyl glycol dimethacrylate are preferably used.

The (meth) acrylic resin may be modified by a reaction between the functional groups of the copolymer. Examples of the reaction include a condensation reaction in a polymer chain between a methyl ester group of methyl (meth) acrylate and a hydroxyl group of 2- (hydroxymethyl) acrylate, a condensation reaction of a carboxyl group of (meth) And a dehydration condensation reaction in a polymer chain with a hydroxyl group of methyl (meth) acrylate).

The glass transition temperature of the (meth) acrylic resin is preferably 80 ° C or more and 160 ° C or less. The glass transition temperature is determined by adjusting the polymerization ratio of the methacrylic acid ester monomer and the acrylic ester monomer, the carbon chain length of each ester group, the kind of the functional group having them, and the polymerization ratio of the polyfunctional monomer to the whole monomer Controllable.

As a means for increasing the glass transition temperature of the (meth) acrylic resin, it is also effective to introduce 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 imide structure, and a lactone structure. Specific examples include a cyclic acid anhydride structure such as an anhydroglutaric acid structure and an anhydrous succinic acid structure; A cyclic imide structure such as a glutarimide structure and a succinimide structure; And lactone ring structures such as butyrolactone and valerolactone.

As the content of the cyclic structure in the main chain is increased, the glass transition temperature of the (meth) acrylic resin tends to be increased.

A cyclic acid anhydride structure and a cyclic imide structure are introduced by copolymerization of a monomer having a cyclic structure such as maleic anhydride or maleimide; A method of introducing a cyclic acid anhydride structure by a dehydration-demethanol condensation reaction after polymerization; A method in which an amino compound is reacted to introduce a cyclic imide structure, or the like.

The resin (polymer) having a lactone ring structure can be obtained by preparing a polymer having a hydroxyl group and an ester group in a polymer chain, and then, by heating, the hydroxyl group and the ester group in the obtained polymer are reacted with an organic phosphorus compound Followed by cyclization and condensation in the presence of a catalyst to form a lactone ring structure.

The (meth) acrylic resin and the thermoplastic resin film formed therefrom may contain additives as required. Examples of additives include lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light stabilizers, impact resistance improvers, surfactants and the like.

These additives can also be used when a thermoplastic resin other than the (meth) acrylic resin is used as the thermoplastic resin constituting the thermoplastic resin film.

The (meth) acrylic resin may contain acrylic rubber particles, which are impact modifiers, from the viewpoints of the film formability to the film and the impact resistance of the film. The acrylic rubber particles are particles of an elastomer mainly composed of an acrylate ester as an essential component and substantially of a single-layer structure composed only of the elastomer, and those of a multi-layer structure having the elastomer as a single layer.

Examples of the elastomer include crosslinked elastic copolymers composed mainly of alkyl acrylates and copolymerized with other vinyl monomers copolymerizable therewith and crosslinkable monomers.

Examples of the alkyl acrylate which is the main component of the elastomer include alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and the alkyl groups having from 1 to 8 carbon atoms. Alkyl acrylate is preferably used.

Examples of the other vinyl monomer copolymerizable with the alkyl acrylate include a compound having one polymerizable carbon-carbon double bond in the molecule, and more specifically, a methacrylic ester such as methyl methacrylate; Aromatic vinyl compounds such as styrene; And vinyl cyan compounds such as acrylonitrile.

Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate (Meth) acrylates of polyhydric alcohols such as methacrylic acid; Alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate; Divinylbenzene and the like.

A laminate of a film made of a (meth) acrylic resin containing no rubber particles and a film made of a (meth) acrylic resin containing rubber particles may be used as the thermoplastic resin film bonded to the polarizer 30. [ Further, a (meth) acrylic resin layer is formed on one side or both sides of the retardation developing layer made of a resin different from the (meth) acrylic resin, and a phase difference is expressed as a thermoplastic resin film to be bonded to the polarizer 30 It is possible.

At least one of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is preferably a film ((meth) acrylic resin film) containing a (meth) acrylic resin, The resin film is preferably laminated to the polarizer 30 through an adhesive layer formed from the adhesive composition according to the present invention.

The adhesive composition according to the present invention can exhibit good adhesiveness (adhesiveness under normal circumstances and adhesiveness after being placed under a moist heat environment (high temperature and high humidity environment)) when the thermoplastic resin film is a (meth) acrylic resin film. Therefore, the adhesive composition according to the present invention can be suitably used for bonding the polarizer and the (meth) acrylic resin film.

The (meth) acrylic resin film is preferably composed of a (meth) acrylic resin.

The first thermoplastic resin film (10) and / or the second thermoplastic resin film (20) may contain an ultraviolet absorber. When a polarizing plate is applied to an image display apparatus such as a liquid crystal display apparatus, a thermoplastic resin film containing an ultraviolet absorber is disposed on the viewer side of an image display element (e.g., a liquid crystal cell) to suppress deterioration of the image display element due to ultraviolet rays .

Examples of the ultraviolet absorber include a salicylic ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, and a nickel complex salt compound.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be a film made of the same thermoplastic resin or a film made of a different thermoplastic resin. The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be the same or different in thickness, presence or absence of additives, kind thereof, retardation characteristics, and the like.

In one embodiment, the first thermoplastic resin film 10 is a (meth) acrylic resin film, and the second thermoplastic resin film 20 is a polyolefin resin film, a cellulose ester resin, or a polyester resin film.

In another embodiment, the first thermoplastic resin film 10 and the second thermoplastic resin film 20 are (meth) acrylic resin films.

The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may have a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antistatic layer, (Coating layer) such as an antifouling layer, a conductive layer, or the like may be provided.

The thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 are usually 5 占 퐉 or more and 200 占 퐉 or less and preferably 10 占 퐉 or more and 120 占 퐉 or less and more preferably 10 占 퐉 or more and 85 占 퐉 More preferably not less than 15 mu m and not more than 65 mu m. The thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be 50 탆 or less and 40 탆 or less, respectively. Reducing the thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is advantageous for reducing the thickness of the polarizing plate and further the image display apparatus.

On the surface to which the adhesive composition of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is applied, surface modification treatment such as saponification treatment, plasma treatment, corona treatment, primer treatment, etc., The surface modification treatment may be omitted from the viewpoint of simplification of the process.

When the first thermoplastic resin film 10 or the second thermoplastic resin film 20 is a cellulose acetate resin film, it is preferable to conduct the saponification treatment from the viewpoint of improving the adhesion. As the saponification treatment, there may be mentioned a method of immersing in an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide.

[4] Production of polarizer, and adhesive layer

1 can be obtained by laminating and bonding the first thermoplastic resin film 10 to one surface of the polarizer 30 through the first adhesive layer 15 so as to obtain the polarizer 30, The second thermoplastic resin film 20 is further laminated and bonded to the side of the second adhesive layer 25 through the second adhesive layer 25 to obtain a polarizing plate having the structure shown in Fig.

In the case of producing a polarizing plate having both the first thermoplastic resin film 10 and the second thermoplastic resin film 20 (hereinafter collectively referred to simply as &quot; thermoplastic resin film &quot;), The thermoplastic resin films on both sides may be laminated and bonded at the same time.

In the polarizing plate having the structure shown in Fig. 1, the first adhesive layer 15 is formed from the adhesive composition related to the present invention. The first adhesive layer 15 may be a cured layer of the adhesive composition according to 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 formed from the adhesive composition related to the present invention. The first adhesive layer 15 and / or the second adhesive layer 25 may be a cured layer of the adhesive composition according to the present invention.

The first adhesive layer 15 and the second adhesive layer 25 in the polarizing plate having the structure shown in Fig. 2 are each formed of the adhesive composition according to the present invention, and the other is the adhesive composition according to the present invention May be formed from different adhesive compositions.

As other adhesive compositions, conventionally known water-based adhesives or active energy ray-curable adhesives can be mentioned.

Examples of the water-based adhesive include conventionally known adhesive compositions using a polyvinyl alcohol resin or a urethane resin as a main component.

When a polyvinyl alcohol resin is used as the main component of the adhesive, the polyvinyl alcohol resin may be a polyvinyl alcohol resin such as partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, or a modified polyvinyl alcohol resin.

The polyvinyl alcohol resin is a polyvinyl alcohol homopolymer obtained by saponifying a copolymer of vinyl acetate and another monomer copolymerizable therewith, as well as a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, It may be combined.

The water-based adhesive containing a polyvinyl alcohol resin preferably contains a curing component such as a polyvalent aldehyde, a melamine compound, a zirconia compound, a zinc compound, a glyoxal, a glyoxal derivative and a water-soluble epoxy resin or a crosslinking agent can do.

As an aqueous adhesive containing a urethane resin as a main component, an aqueous adhesive containing a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group can be mentioned. The polyester-based ionomer-type urethane resin is a urethane resin having a polyester skeleton in which a small amount of an ionic component (hydrophilic component) is introduced.

The active energy ray-curable adhesive is an adhesive which is cured by irradiation of an active energy ray such as ultraviolet ray, visible light, electron ray or X-ray. When an active energy ray-curable adhesive is used, the adhesive layer of the polarizing plate is a cured layer of the adhesive.

The active energy ray-curable adhesive may be an adhesive containing an epoxy compound cured by cationic polymerization as a curable component, and is preferably an ultraviolet curable adhesive containing such an epoxy compound as a curable component. The epoxy-based compound means a compound having an average of at least one, preferably two or more epoxy groups in the molecule. The epoxy compound may be used alone, or two or more epoxy compounds may be used in combination.

Examples of the epoxy compound include a hydrogenated epoxy compound (glycidyl ether of a polyol having an alicyclic ring) obtained by reacting an alicyclic polyol obtained by subjecting an aromatic ring of an aromatic polyol to a hydrogenation reaction, with epichlorohydrin; Aliphatic epoxy compounds such as aliphatic polyhydric alcohols or polyglycidyl ethers of alkylene oxide adducts thereof; And an alicyclic epoxy compound which is an epoxy compound having at least one epoxy group bonded to an alicyclic ring in the molecule.

The active energy ray-curable adhesive may contain, as a curable component, a (meth) acrylic compound that is radically polymerized instead of or in addition to the epoxy compound. Examples of the (meth) acrylic compound include (meth) acrylate monomers having at least one (meth) acryloyloxy group in the molecule; (Meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers obtained by reacting two or more kinds of functional group-containing compounds and having at least two (meth) acryloyloxy groups in the molecule.

When the active energy ray-curable adhesive contains an epoxy compound cured by cationic polymerization as a curable component, it preferably contains a photo cationic polymerization initiator. Examples of photo cationic polymerization initiators include aromatic diazonium salts; Onium salts such as aromatic iodonium salts and aromatic sulfonium salts; Iron-allene complexes and the like.

When the active energy ray-curable adhesive contains a radically polymerizable component such as a (meth) acrylic compound, it preferably contains a photo radical polymerization initiator. Examples of the photo radical polymerization initiator include an acetophenone-based initiator, a benzophenone-based initiator, a benzoin ether-based initiator, a thioxanthone-based initiator, xanthone, fluorenone, camphorquinone, benzaldehyde and anthraquinone.

The polarizer 30 and the thermoplastic resin film may be bonded by applying an adhesive composition to the bonding surface of the polarizer 30 and / or the bonding surface of the thermoplastic resin film, or by injecting an adhesive composition between the polarizer 30 and the thermoplastic resin film And a step of superimposing the films of the two on each other through the layer of the adhesive composition and pressing them from above and below by using a bonding roll or the like.

For forming the adhesive composition layer, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Alternatively, the polarizer 30 and the thermoplastic resin film may be continuously supplied while the joint surfaces of the polarizer 30 and the thermoplastic resin film are inward, and the adhesive composition may be dripped between the polarizer 30 and the thermoplastic resin film.

After the above bonding step, it is preferable that the laminate including the polarizer 30, the adhesive composition layer and the thermoplastic resin film is subjected to heat treatment. The temperature of the heat treatment is, for example, 40 占 폚 or higher and 100 占 폚 or lower, preferably 50 占 폚 or higher and 90 占 폚 or lower. The solvent contained in the adhesive composition layer can be removed by a heat treatment. Further, when the adhesive composition is a curable adhesive composition, the curing / crosslinking reaction can be promoted by the above heat treatment.

Before applying the adhesive composition, one or both of the bonding surfaces of the polarizer 30 and the thermoplastic resin film are subjected to easy adhesion treatment such as saponification treatment, corona discharge treatment, plasma treatment, flame treatment, primer treatment and anchor coating treatment Surface activation treatment) may be performed.

When an active energy ray-curable adhesive is used, the adhesive composition layer is dried, if necessary, after which the active energy ray is irradiated to cure the adhesive composition layer.

The light source used for irradiating the active energy ray may be one capable of generating ultraviolet rays, electron beams, X-rays, and the like. Pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps and the like having a light emission distribution with a wavelength of 400 nm or less are suitably used.

The thickness of the adhesive layer formed from the adhesive composition according to the present invention is, for example, 10 nm or more and 10 m or less, preferably 20 nm or more and 5 m or less, more preferably 30 nm or more and 1 m or less , More preferably not less than 40 nm and not more than 500 nm. The adhesive layer formed from the above-described conventionally known water-based adhesive may have the same thickness as this.

The thickness of the adhesive layer formed from the active energy ray-curable adhesive is, for example, 10 nm or more and 20 m or less, preferably 100 nm or more and 10 m or less, and more preferably 500 nm or more and 5 m or less.

The first adhesive layer 15 and the second adhesive layer 25 may have the same thickness or different thicknesses.

[5] Other components of the polarizer

[5-1] Optically functional film

The polarizing plate may have an optical functional film other than the polarizer 30 for imparting a desired optical function, and a suitable example thereof 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 phase difference film, but the phase difference film may be laminated separately from the thermoplastic resin film. In the latter case, the retardation film can be laminated on the outer surface of the first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 through the adhesive layer or the adhesive layer. Further, a retardation film may be laminated instead of the first thermoplastic resin film 10 or the second thermoplastic resin film 20. For example, a retardation film is formed on the other surface of the polarizer 30 in the single-side protective polarizer plate in which the first thermoplastic resin film 10 is bonded to one surface of the polarizer 30 shown in Fig. 1, Film. In this case, the retardation film can be laminated on the surface of the polarizer 30 through the pressure-sensitive adhesive layer or the adhesive layer.

Examples of the retardation film include a birefringent film composed of a stretched film of a thermoplastic resin having translucency; A film in which a discotic liquid crystal or a nematic liquid crystal is aligned and fixed; And the liquid crystal layer formed on the base film.

The base film is usually a film made of a thermoplastic resin, and one example of the thermoplastic resin is a cellulose ester-based resin such as triacetylcellulose.

As the thermoplastic resin forming the birefringent film, those described in relation to the first and second thermoplastic resin films 10 and 20 can be used.

Examples of other optical functional films (optical members) that can be included in the polarizing plate include a light-collecting plate, a luminance enhancement film, a reflection layer (reflection film), a transflective layer (transflective film), a light diffusion layer (light diffusion film) These are generally formed when 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 optical path control or the like, and may be a prism array sheet, a lens array sheet, a dot-laid sheet, or the like.

The brightness enhancement film is used for the purpose of improving the brightness in a liquid crystal display device to which a polarizing plate is applied. Specifically, a reflection type polarizing separation sheet designed to produce anisotropy in reflectance by stacking a plurality of thin film films having different anisotropy of refractive index from each other, an orientation film of a cholesteric liquid crystal polymer, and an orientation film of the cholesteric liquid crystal polymer supported on the base film A circularly polarized light separation sheet and the like.

The reflection layer, the transflective layer, and the light diffusion layer are respectively formed in order to make the polarizing plate an optical member of a reflection type, a semi-transmission type, and a diffusion type. The polarizing plate of the reflection type is used in a liquid crystal display device of the type in which incident light from the viewer side is reflected and displayed, and since the light source such as a backlight can be omitted, the liquid crystal display device can be easily made thin. The transflective type polarizing plate is used for a liquid crystal display device of a type that is displayed by light from a backlight in a reflection type at a spot and a backlight. Further, the diffusion type polarizing plate is used in a liquid crystal display device in which display defects such as moiré are suppressed by imparting light diffusibility. The reflection layer, the transflective layer and the light diffusion layer can be formed by a known method.

[5-2] Pressure-sensitive adhesive layer

The polarizing plate related to the present invention may include a pressure-sensitive adhesive layer for bonding the polarizing plate to an image display device such as a liquid crystal cell or another optical member. The pressure-sensitive adhesive layer is formed on the outer surface of the polarizer 30 in the polarizing plate having the constitution shown in Fig. 1 and the outer surface of the first thermoplastic resin film 10 or the second thermoplastic resin film 20 in the polarizing plate having the constitution shown in Fig. As shown in FIG.

As the pressure-sensitive adhesive for use in the pressure-sensitive adhesive layer, a (meth) acrylic resin, a silicone resin, a polyester resin, a polyurethane resin, a polyether resin or the like may be used as the base polymer. Among them, (meth) acrylic pressure-sensitive adhesives are preferable from the viewpoints of transparency, adhesive strength, reliability, weather resistance, heat resistance, reworkability and the like.

(Meth) acrylic pressure-sensitive adhesives include (meth) acrylic acid alkyl esters having an alkyl group having 20 or less carbon atoms such as methyl group, ethyl group, n-, i- or t- (Meth) acryl-based monomer having a weight-average molecular weight of 100,000 or more and having a glass transition temperature of preferably 25 占 폚 or lower, more preferably 0 占 폚 or lower, .

The pressure-sensitive adhesive layer may be formed on the polarizing plate by, for example, dissolving or dispersing the pressure-sensitive adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare a pressure-sensitive adhesive liquid and directly coating the pressure- The pressure-sensitive adhesive layer may be formed in a sheet form on the release film subjected to the releasing treatment, and the pressure-sensitive adhesive layer may be applied to the target surface of the polarizing plate.

The thickness of the pressure-sensitive adhesive layer is determined depending on the adhesive strength and the like, but is suitably in the range of 1 占 퐉 to 50 占 퐉, preferably 2 占 퐉 to 40 占 퐉.

The polarizing plate may include the above separate film. The separator film may be a film made of a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, or a polyester-based resin such as polyethylene terephthalate. Among them, a stretched film of polyethylene terephthalate is preferable.

The pressure-sensitive adhesive layer may contain, if necessary, a glass fiber, a glass bead, a resin bead, a filler made of metal powder or other inorganic powder, a pigment, a colorant, an antioxidant, an ultraviolet absorber and an antistatic agent.

Examples of the antistatic agent include ionic compounds, conductive fine particles, and conductive polymers, but ionic compounds are preferably used.

The cation component constituting the ionic compound may be an inorganic cation or an organic cation.

Examples of the organic cations include pyridinium cations, imidazolium cations, ammonium cations, sulfonium cations, phosphonium cations, piperidinium cations and pyrrolidinium cations. Examples of the inorganic cations include lithium ions, potassium ions .

On the other hand, the anionic component constituting the ionic compound may be either an inorganic anion or an organic anion, but an anionic component containing a fluorine atom is preferable in that an ionic compound having excellent antistatic property is given. As an anion component containing a fluorine atom, a hexafluorophosphate anion [(PF ₆ ^-)], bis (methanesulfonyl trifluoromethanesulfonyl) imide anion _{[(CF 3 SO 2) 2} N -] anion, bis ( Fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N ^- ] anion and the like.

[5-3] Protect Film

The polarizing plate related to the present invention may include a protective film for protecting the surface (typically, the surface of the thermoplastic resin film). The polarizing plate is bonded to an image display element or another optical member, for example, and then the pressure-sensitive adhesive film of the polarizing plate is peeled off.

The protective film is composed of, for example, a base film and a pressure-sensitive adhesive layer laminated thereon. As for the pressure-sensitive adhesive layer, the above-mentioned technique is cited.

Examples of the resin constituting the base film include polyethylene resins such as polyethylene, polypropylene resins such as polypropylene, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, and thermoplastic resins such as polycarbonate resins have. Preferably, it is a polyester resin such as polyethylene terephthalate.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, "%" and "parts" indicating the content or amount are based on mass unless otherwise specified.

In Table 1, the oxazoline group-containing polymer (A), the nitrogen-nitrogen heterocycle compound (B) and the polyvinyl alcohol polymer (C) are abbreviated as (A), (B) and (C), respectively.

(Production Example 1: Production of (meth) acrylic resin film)

A copolymer of methyl methacrylate / methyl acrylate = 96% / 4% (by mass) as a (meth) acrylic resin was prepared. Also, it is preferable that the innermost layer is made of a hard polymer obtained by polymerizing methyl methacrylate with a small amount of allyl methacrylate as the rubber particles, and the intermediate layer contains butyl acrylate as a main component and styrene and a small amount of allyl methacrylate Layered structure composed of a soft polymer polymerized in the outermost layer and a hard polymer polymerized by using methyl methacrylate in a small amount of ethyl acrylate as an outer layer and having an average particle diameter of up to 240 nm. In this rubber particle, the total mass of the innermost layer and the intermediate layer was 70% of the whole particles.

68.5% by mass of the (meth) acrylic resin, 29.6% by mass of the rubber particles, and 1.9% by mass of an ultraviolet absorber "Adekastab LA31" manufactured by ADEKA Co., Ltd. were mixed by a super mixer and melt-kneaded by a twin screw extruder did. The pellets were poured into a 65 mm single screw extruder and extruded through a T-die having a set temperature of 275 deg. C to cool the both surfaces of the two polishing roll films having mirror surfaces to obtain a (meth) acrylic To obtain a resin film.

(Production Example 2: Production of Polarizer)

A polyvinyl alcohol film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and a thickness of 60 탆 was immersed in pure water at 30 캜 and then immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.02 / Immersed. Thereafter, it was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Subsequently, the film was washed with pure water at 8 캜 and dried at 65 캜 to obtain a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol. The stretching was performed mainly in a step of iodine dyeing and boric acid treatment. The total stretching magnification was 5.5 times, and the thickness of the obtained polarizer was 23 占 퐉.

&Lt; Example 1 >

(1) Preparation of adhesive composition

The components shown in Table 1 were mixed together with the pure water as a solvent in the amounts shown in Table 1 to prepare an adhesive composition (aqueous adhesive solution). The unit of the blending amount of each component shown in Table 1 is the mass part, and the blending amount of each component is the amount by solid content conversion. The solid content concentration (the total concentration of the components (A), (B) and (C) in the adhesive composition) in the obtained adhesive composition was 7.1% by mass. The obtained adhesive composition was subjected to pH measurement using a handy pH meter (&quot; D-51 &quot;, manufactured by HORIBA), and the pH at 25 캜 was 8.3.

(2) Production of Polarizer

(Meth) acrylic resin film prepared in Preparation Example 1 was subjected to corona treatment, and the surface of the (meth) acrylic resin film subjected to the corona treatment and the surface of the triacetylcellulose (TAC) film subjected to the saponification treatment The adhesive composition prepared in the above (1) was coated on one side of a film (trade name &quot; KC2UAW &quot;, thickness: 25 占 퐉, manufactured by Konica Minolta Opto) using a bar coater. (Meth) acrylic resin film was laminated on one side of the polarizer produced in Production Example 2 and the other side was laminated with a TAC film having been saponified so that the adhesive composition layer was on the side of the polarizer, A laminate having a layer structure of a resin film / adhesive composition layer / polarizer / adhesive composition layer / TAC film was obtained. This laminate was passed through a hot-air dryer to carry out a heat treatment at 80 DEG C for 300 seconds and then cured at 25 DEG C for 72 hours to prepare a polarizing plate.

(3) Evaluation of adhesion

(3-1) Initial adhesion

The initial adhesion between the (meth) acrylic resin film and the polarizer in the polarizing plate obtained in the above (2) was evaluated as follows. The initial adhesion property refers to the polarizing plate before the wet heat treatment to be described later, which is the adhesion property with respect to the polarizing plate which has been stored under the environment of a temperature of 23 DEG C and a relative humidity of 55% after the production.

The surface of the (meth) acrylic resin film in the polarizing plate was subjected to a corona discharge treatment, and a (meth) acrylic pressure sensitive adhesive sheet was bonded to the corona discharge treated surface to obtain a polarizer with a pressure-sensitive adhesive layer. A test piece having a width of 25 mm and a length of about 200 mm was cut from the obtained polarizer with a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer surface was bonded to the soda glass substrate.

Subsequently, a cutter blade was inserted between the (meth) acrylic resin film and the polarizer and peeled 30 mm from the end in the longitudinal direction. The peeled portion was peeled off with a universal tensile tester (trade name "AG-1" manufactured by Shimadzu Corporation) ] In the grip. The test piece in this state was subjected to a grip moving speed of 300 mm / sec in an atmosphere at a temperature of 23 DEG C and a relative humidity of 55% in accordance with JIS K 6854-2: 1999 "Adhesive-peel adhesion strength test method- Min to determine the average peeling force over a length of 170 mm excluding the 30 mm portion of the grip portion. The results are shown in Table 1. In Table 1, &quot; * &quot; indicates that the (meth) acrylic resin film or the polarizer was broken before the peeling at the interface between the (meth) acrylic resin film and the polarizer occurred do.

The initial adhesion between the (meth) acrylic resin film and the polarizer was evaluated in the following three stages based on the obtained measurement of the adhesion force. The results are also shown in Table 1.

A: Adhesion exceeds 5N.

B: Adhesion is in the range of 1 to 5 N.

C: Adhesion is less than 1 N.

(3-2) Adhesion after moist heat treatment

The adhesion between the (meth) acrylic resin film and the polarizer in the polarizing plate obtained in the above (2) after wet heat treatment was evaluated according to the following.

The surface of the (meth) acrylic resin film in the polarizing plate was subjected to a corona discharge treatment, and a (meth) acrylic pressure sensitive adhesive sheet was bonded to the corona discharge treated surface to obtain a polarizer with a pressure-sensitive adhesive layer. A test piece having a width of 25 mm and a length of about 200 mm was cut from the obtained polarizer with a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer surface was bonded to the soda glass substrate.

The test piece was stored for 48 hours in an environment at 85 ° C and 85% relative humidity, and then stored at 23 ° C in a relative humidity of 55% for one night.

Subsequently, the adhesion was measured in the same manner as in (3-1), and the adhesion was evaluated. The results are shown in Table 1.

&Lt; Examples 2 to 41 and Comparative Examples 1 to 10 >

An adhesive composition was prepared in the same manner as in Example 1 except that the blending components and the blending amounts thereof were changed as shown in Table 1.

Table 1 shows the solid content concentration and pH of the obtained adhesive composition.

A polarizing plate was produced in the same manner as in Example 1 except that the obtained adhesive composition was used, and the initial adhesion between the (meth) acrylic resin film and the polarizer and the adhesion after the wet heat treatment were measured, And the adhesion was evaluated. The results are shown in Table 1.

Details of each component shown in Table 1 are as follows.

a1: aqueous solution of oxazoline group-containing acrylic polymer having a 2-oxazoline group as a side chain, solid content concentration: 10 mass%, oxazoline value (theoretical value): 130 g solid content / eq., the amount of oxazoline group (theoretical value): 7.7 mmol / g, solids content, number average molecular weight: 4 x 10 ⁴ , weight average molecular weight: 12 x 10 ⁴ )

b1: trade name "CROSSLINKER CL-427" [compound having three aziridine groups in the molecule] manufactured by MENADIONA Co.,

b2: trade name "CROSSLINKER CL-467" [compound having three aziridine groups in the molecule] manufactured by MENADIONA Co.,

b3: &quot; Chemitate PZ-33 &quot; (a compound having three aziridine groups in the molecule) manufactured by Nippon Shokubai Co.,

b4: &quot; Chemitite DZ-22E &quot; (a compound having two aziridine groups in the molecule) manufactured by Nippon Shokubai Co.,

b5: Piperidine [Solid content concentration: 100% by mass]

b6: 4-picoline [solid content concentration: 100 mass%]

b7: 3,5-Diethylpyridine [solid concentration: 100% by mass]

b8: 1,4-bis (3-aminopropyl) piperazine [solid concentration: 100% by mass]

c1: trade name "Gosenex Z-200" [acetoacetyl group-modified polyvinyl alcohol, average degree of polymerization: 1100, saponification degree: 99.0 mol% or more] manufactured by Nippon Synthetic Chemical Industry Co.,

c2: trade name &quot; AF-17 &quot; [carboxyl group-modified polyvinyl alcohol, average degree of polymerization: 1700, degree of saponification: 96.5 mol% or more] manufactured by Nihon Sakubi-

B1 (trade name &quot; CROSSLINKER CL-427 &quot; manufactured by MENADIONA) has the following structure.

B2 (trade name &quot; CROSSLINKER CL-467 &quot;, manufactured by MENADIONA) has the following structure.

B3 (trade name &quot; Chemitite PZ-33 &quot;, manufactured by Nippon Shokubai Co., Ltd.) has the following structure.

B4 (trade name &quot; Chemite DZ-22E &quot;, manufactured by Nippon Shokubai Co., Ltd.) has the following structure.

10: first thermoplastic resin film, 15: first adhesive layer, 20: second thermoplastic resin film, 25: second adhesive layer, 30: polarizer.

Claims (11)

An adhesive composition comprising an oxazoline group-containing polymer (A) and a nitrogen-containing heterocyclic compound (B). The adhesive composition according to claim 1, wherein the nitrogen-containing heterocyclic compound (B) is a compound having an aziridine ring. The adhesive composition according to claim 1 or 2, wherein the nitrogen-containing heterocyclic compound (B) is a compound having two or more nitrogen-containing heterocyclic rings in the molecule. The adhesive composition according to claim 1 or 2, wherein the oxazoline group-containing polymer (A) is a water-soluble polymer. The adhesive composition according to claim 1 or 2, wherein the oxazoline group-containing polymer (A) is a polymer having an oxazoline group in its side chain. The adhesive composition according to Claim 1 or 2, wherein the content of the nitrogen-containing heterocyclic compound (B) is 0.1 part by mass or more and 50 parts by mass or less based on 100 parts by mass of the oxazoline group-containing polymer (A). The adhesive composition according to claim 1 or 2, further comprising a polyvinyl alcohol polymer (C). The adhesive composition according to claim 7, wherein the polyvinyl alcohol polymer (C) comprises at least one polymer selected from the group consisting of an acetoacetyl group-modified polyvinyl alcohol polymer and a carboxyl group-modified polyvinyl alcohol polymer. The adhesive composition according to claim 7, wherein the content of the polyvinyl alcohol polymer (C) is 1 part by mass or more and 300 parts by mass or less based on 100 parts by mass of the oxazoline group-containing polymer (A). The adhesive composition according to claim 1 or 2, wherein the adhesive composition is used for bonding the polarizer to the (meth) acrylic resin film. A polarizer,
(Meth) acrylic resin film laminated on the polarizer through an adhesive layer
/ RTI &gt;
Wherein the adhesive layer is a layer formed from the adhesive composition according to claim 1 or 2. [

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