TW202233409A - Curable adhesive composition and polarizer - Google Patents

Abstract

A problem to be solved by the present invention is to provide a curable adhesive composition suitable for bonding a polarizer to a thermoplastic resin film, and a polarizing plate including sequentially a polarizer, an adhesive layer and a thermoplastic resin film, wherein the polarizer has good adhesion to the thermoplastic resin film. A solution to the problem is to provide a curable adhesive composition containing a maleic anhydride-modified compound (A), an unmodified polybutene (B), a (meth) acrylate compound (C) and a photopolymerization initiator (D), and a polarizing plate including sequentially a polarizer, an adhesive layer and a thermoplastic resin film, wherein the adhesive layer is a cured product layer of the curable adhesive composition.

Description

Curable adhesive composition and polarizing plate

The present invention relates to a curable adhesive composition and a polarizing plate.

Polarizing plates, which are widely used in image display devices such as liquid crystal display devices and organic EL display devices, generally have a structure in which a thermoplastic resin film such as a protective film is laminated on one or both sides of the polarizer. Adhesives are usually used for lamination of polarizers and thermoplastic resin films. As such adhesives, active energy ray-curable adhesives and water-based adhesives are known [for example, Japanese Patent Laid-Open No. 2009-008860 (Patent Document 1)].

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-008860

An object of the present invention is to provide a curable adhesive composition suitable for bonding a polarizer and a thermoplastic resin film. Another object of the present invention is to provide a polarizer, which includes a polarizer, an adhesive layer, and a thermoplastic resin film in sequence, and has good adhesion between the polarizer and the thermoplastic resin film.

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

[1] A curable adhesive composition comprising: maleic anhydride modified compound (A), unmodified polybutene (B), (meth)acrylate compound (C), and photopolymerization Starter (D).

[2] The curable adhesive composition according to [1], wherein in 100 mass % of the total amount of the maleic anhydride-modified compound (A) and the unmodified polybutene (B), Content of the said maleic anhydride modified compound (A) is 40 mass % or more and 90 mass % or less.

[3] The curable adhesive composition according to [1] or [2], wherein the (meth)acrylate compound (C) contains a monofunctional (meth)acrylate compound (C-1) .

[4] The curable adhesive composition according to [3], wherein in 100% by mass of the (meth)acrylate compound (C), the monofunctional (meth)acrylate compound (C-1 ) content is 60 mass % or more and 99 mass % or less.

[5] The curable adhesive composition according to [3] or [4], wherein the monofunctional (meth)acrylate compound (C-1) contains an alicyclic (meth)acrylate compound selected from the group consisting of At least one compound of the group consisting of an alkyl ester compound and an aromatic (meth)acrylate compound.

[6] The curable adhesive composition according to any one of [3] to [5], wherein the monofunctional (meth)acrylate compound (C-1) contains (meth)acrylate Cyclic alkyl ester compounds and (meth)acrylic acid straight or branched chain C ₄ -C ₃₆ alkyl ester compounds.

[7] The curable adhesive composition according to [6], wherein the (meth)acrylic acid alicyclic alkyl ester compound and the (meth)acrylic acid linear or branched chain C ₄ -C ₃₆ Content of the said (meth)acrylic-acid alicyclic alkyl ester compound is 30 mass % or more and 80 mass % or less in 100 mass % of the total amounts of alkyl ester compounds.

[8] The curable adhesive composition according to any one of [1] to [7], further comprising a petroleum resin (E).

[9] The curable adhesive composition according to any one of [1] to [8], wherein the maleic anhydride-modified compound (A) contains a maleic anhydride-modified polymer (A-1).

[10] The curable adhesive composition according to any one of [1] to [9], wherein the cured film with a thickness of 10 μm composed of the curable adhesive composition is exposed to a temperature of 40° C. and a relative humidity In 90%, it has a moisture permeability of 400g/(m ² .24hr) or less.

[11] A polarizing plate comprising a polarizer, an adhesive layer and a thermoplastic resin film in this order, wherein,

The aforementioned adhesive layer is a cured product layer of the curable adhesive composition according to any one of [1] to [10].

[12] The polarizing plate according to [11], wherein the thermoplastic resin film is a (meth)acrylic resin film.

The present invention can provide a curable adhesive composition and a polarizing plate, the curable adhesive composition is suitable for laminating a polarizer and a thermoplastic resin film, and the polarizing plate includes a polarizer, an adhesive layer and a thermoplastic resin film in sequence , and the adhesion between the polarizer and the thermoplastic resin film is good.

10: First thermoplastic resin film

15: The first adhesive layer

20: Second thermoplastic resin film

25: Second Adhesive Layer

30: polarizer

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

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

<Curable adhesive composition>

The curable adhesive composition of the present invention (hereinafter also referred to as "adhesive composition") is suitable for the bonding of thermoplastic resin films, for example, it can be used for lamination of thermoplastic resin films and other thermoplastic resin films (or layers). An application example of the adhesive composition of the present invention is for polarizing plates, that is, it can be used for producing polarizing plates. More specifically, the adhesive composition of the present invention can be used for an adhesive composition for bonding a polarizer and a thermoplastic resin film.

In this specification, the polarizing plate refers to a laminated optical film including a "polarizer" and a "thermoplastic resin film laminated on one side or both sides". In the polarizing plate, the polarizing plate and the thermoplastic resin film are laminated via an adhesive layer. The adhesive layer is a layer formed of an adhesive composition, more specifically, a cured product layer of the adhesive composition.

The polarizing plate may contain films or layers other than the polarizing plate and the above-mentioned thermoplastic resin film.

The above-mentioned adhesive composition is a cured product containing a maleic anhydride modified compound (A), an unmodified polybutene (B), a (meth)acrylate compound (C) and a photopolymerization initiator (D). flexible adhesive composition. The adhesive composition may contain components other than these components.

Incidentally, in this specification, the compounds exemplified as the respective components contained or contained in the adhesive composition may be used alone or in combination unless otherwise specified.

[1] Maleic anhydride modified compound (A)

The maleic anhydride modified compound (A) is a compound containing a maleic anhydride structure in the molecule. The adhesive composition may contain one kind of maleic anhydride modified compound (A) or two or more kinds of maleic anhydride modified compound (A).

The maleic anhydride-modified compound (A) includes a maleic anhydride-modified polymer (A-1).

The maleic anhydride-modified polymer (A-1) is a polymer modified by introducing a maleic anhydride structure as a polymer side chain. The adhesive composition may contain one type of maleic anhydride-modified polymer (A-1) or two or more types of maleic anhydride-modified polymer (A-1).

The above-mentioned maleic anhydride structure means the following structure.

* Indicates the bond to the main chain.

Among the maleic anhydride-modified polymers (A-1), the polymers to be modified with maleic anhydride include diene-based polymers, polyolefin-based polymers, and (meth)acrylic-based polymers. polymers, polyester-based polymers, polystyrene-based polymers, polyether-based polymers, and the like. These polymers may be a homopolymer composed of one kind of monomer or a copolymer composed of two or more kinds of monomers.

In this specification, "(meth)acrylic acid" means at least 1 sort(s) chosen from the group which consists of acrylic acid and methacrylic acid. The same applies to expressions such as "(meth)acryloyl group" and "(meth)acrylate".

The maleic anhydride-modified polymer (A-1) is preferably maleic anhydride-modified polybutadiene. These polymers can be homopolymers or copolymers, respectively. In the case of copolymers, the comonomers are, for example, olefin monomers.

The polybutadiene may be 1,4-polybutadiene or 1,2-polybutadiene, and may also contain a structural unit formed by 1,4-addition and a unit formed by 1,2-addition. Form the constituent units of both. The 1,4-addition can be trans-addition or cis-addition.

The maleic anhydride-modified polymer (A-1) is preferably in a liquid state from the viewpoint of being able to prepare a solvent-free adhesive composition having good adhesiveness. The term "liquid state" means that which exhibits fluidity at a temperature of 25°C.

From the viewpoint of obtaining an adhesive composition with good coatability, the viscosity of the liquid maleic anhydride-modified polymer (A-1) at 25°C is usually 1Pa. 1300Pa above sec. sec or less, preferably 10Pa. 1000Pa above sec. sec or less, preferably 15Pa. 700Pa above sec. sec or less, more preferably 15Pa. 150Pa above sec. sec or less.

The number average molecular weight of the maleic anhydride-modified polymer (A-1) is usually 500 or more and 15,000 or less, preferably 600 or more and 12,000 or less, particularly preferably 700 or more and 10,000, from the viewpoint of viscosity and coatability. Below, more preferably 2000 or more and 10000 or less.

The number average molecular weight of the maleic anhydride-modified polymer (A-1) can be measured as a standard polystyrene conversion value obtained by gel permeation chromatography (GPC: Gel Permeation Chromatography).

The acid value of the maleic anhydride-modified polymer (A-1) is usually 10KOHmg/g or more and 200KOHmg/g or less. From the viewpoint of the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer), etc., It is preferably 15KOHmg/g or more and 150KOHmg/g or less, more preferably 20KOHmg/g or more and 100KOHmg/g or less, more preferably 45KOHmg/g or more and 80KOHmg/g or less. If the maleic anhydride-modified polymer (A-1) with an acid value in this range is used, it is beneficial to improve the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer). Polarizer as a polarizer In this case, it is advantageous to provide an adhesive composition with high adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film.

The acid value of the maleic anhydride-modified polymer (A-1) was measured by neutralization titration method using phenolphthalein as an indicator in accordance with JIS K 0070:1992.

When the total amount of the adhesive composition is 100% by mass, the content of the maleic anhydride-modified compound (A) is usually 3% by mass or more and 40% by mass or less. From the adhesive composition to the thermoplastic resin film ( From the viewpoint of the adhesion ability of the polyvinyl alcohol-based polarizer and the thermoplastic resin film, especially in the case of using a polyvinyl alcohol-based polarizer as the polarizer, from the viewpoint of improving the adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film, Preferably it is 5 mass % or more and 35 mass % or less, More preferably, it is 10 mass % or more and 30 mass % or less.

[2] Unmodified polybutene (B)

The unmodified polybutene (B) is unmodified polybutene, and is a polymer obtained by addition polymerization of butene. The so-called unmodified means that the side chain does not contain reactive groups or polar groups. The structural unit derived from butene contained in the unmodified polybutene (B) is preferably a structural unit mainly derived from isobutene, and may further contain a structural unit derived from n-butene. The adhesive composition may contain one kind of unmodified polybutene or two or more kinds of unmodified polybutene.

The unmodified polybutene (B) is preferably in a liquid state from the viewpoint of being able to prepare a solvent-free adhesive composition having good adhesiveness. The term "liquid" means one that exhibits fluidity at a temperature of 25°C.

From the viewpoint of obtaining an adhesive composition with good coatability, the viscosity of the liquid unmodified polybutene (B) at 25°C is preferably 0.01Pa. sec above 5Pa. sec or less, preferably 0.02Pa. sec above 3Pa. sec or less, more preferably 0.03Pa. sec above 2Pa. sec or less.

The number average molecular weight of the unmodified polybutene (B) is usually 200 or more and 1500 or less, and from the viewpoint of viscosity and coatability, preferably 250 or more and 1000 or less, and particularly preferably 300 or more and 600 or less. The number average molecular weight of the unmodified polybutene (B) can be measured by a vapor pressure molecular weight measurement method.

When the total amount of the adhesive composition is 100% by mass, the content of the unmodified polybutene (B) is usually 1% by mass or more and 20% by mass or less, from the adhesive composition to the thermoplastic resin film (or layer) ), especially in the case of using a polyvinyl alcohol-based polarizer as the polarizer, from the viewpoint of improving the adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film, it is preferable It is 2 mass % or more and 18 mass % or less, More preferably, it is 3 mass % or more and 15 mass % or less.

The total amount of the maleic anhydride-modified compound (A) and the unmodified polybutene (B) is usually 4 mass % or more and 60 mass % or less when the total amount of the adhesive composition is 100 mass %. , from the viewpoint of the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer), especially in the case of using a polyvinyl alcohol-based polarizer as a polarizer, from the viewpoint of improving the polyvinyl alcohol-based polarizer and the thermoplastic resin film From the viewpoint of the adhesion between them, it is preferably 5 mass % or more and 50 mass % or less, more preferably 10 mass % or more and 40 mass % or less, and more preferably 15 mass % or more and 30 mass % or less.

When the total amount of the maleic anhydride-modified compound (A) and the unmodified polybutene (B) in the adhesive composition is 100% by mass, the content of the unmodified polybutene (B) Usually, it is 5 mass % or more and 65 mass % or less. From the viewpoint of the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer), especially when a polyvinyl alcohol-based polarizer is used as the polarizer, the increase in the From the viewpoint of the adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film, it is preferably 10% by mass or more and 60% by mass or less, particularly preferably 20% by mass or more and 50% by mass or less.

Assuming that the total amount of the maleic anhydride-modified compound (A) and the unmodified polybutene (B) in the adhesive composition is 100% by mass, about the maleic anhydride-modified compound (A) ) content, From the viewpoint of the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer), especially in the case of using a polyvinyl alcohol-based polarizer as the polarizer, it is necessary to improve the bond between the polyvinyl alcohol-based polarizer and the thermoplastic resin film. From the viewpoint of the adhesion between each other, 40 mass % or more and 90 mass % or less are preferable, and 50 mass % or more and 80 mass % or less are particularly preferable.

[3] (Meth)acrylate compound (C)

The (meth)acrylate compound (C) is a radically polymerizable compound having one or more (meth)acryloyloxy groups in the molecule.

The adhesive composition may contain one or two or more (meth)acrylate compounds (C).

The (meth)acrylate compound (C) includes a monofunctional (meth)acrylate compound (C-1) having one (meth)acryloyloxy group in a molecule, and a monofunctional (meth)acrylate compound (C-1) having two ( Bifunctional (meth)acrylate compound of meth)acryloyloxy group (C-2), polyfunctional (meth)acrylate compound having 3 or more (meth)acryloyloxy groups in the molecule ( C-3).

The (meth)acrylate compound (C) may contain one or more of the monofunctional (meth)acrylate compound (C-1), the bifunctional (meth)acrylate compound (C-2), and the Polyfunctional (meth)acrylate compound (C-3).

An example of the monofunctional (meth)acrylate compound (C-1) is an alkyl (meth)acrylate. Alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-(meth)acrylate Butyl, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, Isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, hard (meth)acrylate Fatty ester, (meth)acrylic acid iso Linear or branched alkyl (meth)acrylate compounds such as stearyl, isotetradecyl (meth)acrylate, behenyl (meth)acrylate, and tetradecyl (meth)acrylate.

Another example of the monofunctional (meth)acrylate compound (C-1) includes, for example:

Aralkyl (meth)acrylates such as benzyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, phenoxyethylene glycol (meth)acrylate, (meth)acrylic acid Phenoxy (meth)acrylates such as 2-hydroxy-3-phenoxypropyl ester, ethoxylated o-phenylphenol (meth)acrylate, etc. are bonded to ester bonds (-C(=O)-O- ) of the -O- of the aromatic (meth)acrylate compound containing an aromatic ring;

Cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, dicyclopentyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, (meth) (Meth) cycloaliphatic alkyl acrylate compounds with alicyclic ring as the base of -O- bonded to ester bond (-C(=O)-O-), such as isocamphenyl acrylate;

(Meth) acrylic acid N,N-dimethylamine ethyl ester and other (meth) acrylate amino alkyl ester compounds;

Dicyclopentenyloxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, tetrahydrofuran methyl (meth)acrylate, etc. are bonded to ester bonds (-C(=O)-O- The group of -O- of ) is a (meth)acrylate compound which contains an ether bond and is other than the above, etc.

Another example of the monofunctional (meth)acrylate compound (C-1) includes, for example:

2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxy (meth)acrylate Propyl ester, trimethylolpropane mono(meth)acrylate trimethylolpropane, neotaerythritol mono(meth)acrylate, etc. bonded to ester bond (-C(=O)-O-) The group of -O- contains a hydroxyl group (meth)acrylate compound;

2-carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone (n≒2) mono(meth)acrylate, 1-[2-(meth)acryloyloxyethyl phthalate yl] ester, 1-[2-(meth)acryloyloxyethyl] hexahydrophthalate, 1-[2-(meth)acryloyloxyethyl] succinate, trimene 4-[2-(meth)propenyloxy triacid ethyl] ester, N-(meth)acryloyloxy-N',N'-dicarboxymethyl-p-phenylenediamine, etc. bonded to ester bond (-C(=O)-O-) The group of -O- contains a (meth)acrylate compound and the like of a carboxyl group.

Examples of the bifunctional (meth)acrylate compound (C-2) include alkanediol di(meth)acrylate, polyoxyalkanediol di(meth)acrylate, and halogen-substituted alkanediol di(meth)acrylate. base) acrylates, di(meth)acrylates of aliphatic polyols, di(meth)acrylates of hydrogenated dicyclopentadiene or tricyclodecanedialkanol, dioxane glycols Or the di(meth)acrylate of dioxanedialkanol, the di(meth)acrylate of the alkylene oxide adduct of bisphenol A or bisphenol F, the di(meth)acrylate of bisphenol A or bisphenol F base) epoxy acrylate, etc.

When more specific examples of the bifunctional (meth)acrylate compound (C-2) are given, there are ethylene glycol di(meth)acrylate and 1,3-butanediol di(meth)acrylate , 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, neotaerythritol di(meth)acrylate, di(trimethylolpropane)di(meth)acrylate, di(meth)acrylate Ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate base) acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, polysiloxane di(meth)acrylate, neopentyl glycol hydroxytrimethylacetic acid Esters of di(meth)acrylate, 2,2-bis[4-(meth)acryloyloxyethoxyethoxyphenyl]propane, 2,2-bis[4-(meth)propene] Ethoxyethoxyethoxycyclohexyl]propane, dicyclopentadienyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, di(meth)acrylic acid 1, 3-dioxane-2,5-diyl-ester [alias: dioxanediol di(meth)acrylate], acetal compound of hydroxytrimethylacetaldehyde and trimethylolpropane [chemical name : 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane] di(meth)acrylate, tris(hydroxyl) Ethyl) Isocyanate di(meth)acrylate, di(meth)propylene ethoxylated bisphenol A Acrylate, di(meth)acrylate of propoxylated bisphenol A, di(meth)acrylate of ethoxylated bisphenol F, di(meth)acrylate of propoxylated bisphenol F, and the like.

The bifunctional (meth)acrylate (C-2) preferably has at least one alicyclic skeleton or at least one aromatic ring in the molecule, and more preferably has at least one aromatic ring.

From the viewpoints of moisture permeability of the cured product, compatibility with the maleic anhydride-modified compound (A), and adhesion with thermoplastic resin films (especially (meth)acrylic resin films), The bifunctional (meth)acrylate (C-2) preferably contains a compound represented by the following formula, and is particularly preferably a compound represented by the following formula.

In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group, X represents ethylene oxide (-C ₂ H ₄ O-) or propylene oxide (-C ₃ H ₆ O-), and n represents 1 an integer from 1 to 20, and m represents an integer from 1 to 20.

X is preferably ethylene oxide, and the average of the sum of m and n is preferably 2 to 20, more preferably 3 to 15, more preferably 4 to 13.

Examples of the polyfunctional (meth)acrylate compound (C-3) having three or more (meth)acryloyloxy groups in the molecule include: glycerol tri(meth)acrylate, alkoxylated glycerol tri(methyl) ) acrylate, trimethylolpropane tri(meth)acrylate, di(trimethylolpropane) tri(meth)acrylate, di(trimethylolpropane) tetra(meth)acrylate, new Pentaerythritol tri(meth)acrylate, Neotaerythritol tetra(meth)acrylate, Dipivalerythritol tetra(meth)acrylate, Dipionaerythritol penta(meth)acrylate, Di Poly(meth)acrylates of trifunctional or higher aliphatic polyols such as neotaerythritol hexa(meth)acrylate;

Poly(meth)acrylates of halogen-substituted polyols with more than 3 functions;

Tri(meth)acrylates of alkylene oxide adducts of glycerol;

Tri(meth)acrylates of alkylene oxide adducts of trimethylolpropane;

1,1,1-Tris[(meth)propenyloxyethoxyethoxy]propane;

Tris(hydroxyethyl)trimeric isocyanotri(meth)acrylate and the like.

The (meth)acrylate compound (C) preferably contains a monofunctional (methyl) ) acrylate compound (C-1).

The content of the monofunctional (meth)acrylate compound (C-1) is usually 60% by mass or more, when the total amount of the (meth)acrylate compound (C) is 100% by mass, from the adhesive composition From the viewpoint of the adhesiveness of the thermoplastic resin film (or layer), it is preferably 70% by mass or more, particularly preferably 80% by mass or more.

The content of the monofunctional (meth)acrylate compound (C-1) may be 100% by mass when the total amount of the (meth)acrylate compound (C) is set to 100% by mass, depending on the adhesive composition From the viewpoint of the mechanical strength of the cured product and the mechanical strength of the polarizing plate produced using the adhesive composition, it is preferably 99% by mass or less, more preferably 98% by mass or less, and may be 90% by mass or less.

When the content of the monofunctional (meth)acrylate compound (C-1) is less than 100% by mass, the remainder of the (meth)acrylate compound (C) is a bifunctional (meth)acrylate compound ( C-2) and/or the polyfunctional (meth)acrylate compound (C-3) preferably contain a bifunctional (meth)acrylate compound (C-2).

The monofunctional (meth)acrylate compound (C-1) is preferred from the viewpoint of reducing the viscosity of the adhesive composition and the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer) It contains at least one compound selected from the group consisting of an alicyclic alkyl (meth)acrylate compound and an aromatic (meth)acrylate compound.

In addition, from the viewpoint of the wet-heat durability of the polarizing plate using the polyvinyl alcohol-based polarizer, that is, from the viewpoint of providing a tightness between the polyvinyl alcohol-based polarizer and the thermoplastic resin film even after being placed in a humid-heat environment, From the viewpoint of a polarizing plate with good adhesion, the monofunctional (meth)acrylate compound (C-1) preferably contains a (meth)acrylate alicyclic alkyl ester compound and a (meth)acrylate linear chain Or at least one of the group consisting of branched chain C ₄ -C ₃₆ alkyl ester compounds, particularly preferably alicyclic alkyl ester compounds of (meth)acrylic acid and (meth)acrylic acid straight or branched chain C ₄ -C ₃₆ alkyl ester compound.

(Meth) acrylic acid straight chain or branched chain C ₄ -C ₃₆ alkyl ester compound, for example: butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate , Nonyl (meth)acrylate, Decyl (meth)acrylate, Isodecyl (meth)acrylate, Undecyl (meth)acrylate, Lauryl (meth)acrylate, Lauryl (meth)acrylate ester, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, isotetradecyl (meth)acrylate, behenyl (meth)acrylate, (Meth) tetradecyl acrylate, etc.

From the viewpoint of the wet-heat durability of the polarizing plate using the polyvinyl alcohol-based polarizer, the number of carbon atoms in the (meth)acrylic acid linear or branched C ₄ -C ₃₆ alkyl ester compound is preferably 8 or more, particularly preferred 10 or more, particularly preferably 12 or more. The number of carbon atoms may be 24 or less, or 22 or less.

The monofunctional (meth)acrylate compound (C-1) includes both (meth)acrylate cycloaliphatic alkyl ester compounds and (meth)acrylate linear or branched C ₄ -C ₃₆ alkyl ester compounds In this case, from the viewpoint of the adhesive ability of the adhesive composition and the wet heat durability of the polarizing plate using the polyvinyl alcohol-based polarizer, in the (meth)acrylate alicyclic alkyl ester compound and the (methyl) The content of the (meth)acrylic cycloaliphatic alkyl ester compound is preferably 30 mass % or more and 90 mass % or less in the total amount of acrylic acid straight-chain or branched chain C ₄ -C ₃₆ alkyl ester compounds in 100 mass %, particularly preferably It is 30 mass % or more and 80 mass % or less, more preferably 40 mass % or more and 75 mass % or less, and particularly preferably 50 mass % or more and 70 mass % or less.

When the total amount of the adhesive composition is 100% by mass, the content of the (meth)acrylate compound (C) is usually 15% by mass or more and 75% by mass or less, from the adhesive composition to the thermoplastic resin film (or From the viewpoint of the bonding ability of the layer), it is preferably 15 mass % or more and 70 mass % or less, and particularly preferably 20 mass % or more and 60 mass % or less.

[4] Photopolymerization initiator (D)

The photopolymerization initiator (D) is not particularly limited as long as it can generate active radicals, acids, etc. by the action of light, and can start the polymerization of the (meth)acrylate compound (C).

The adhesive composition may contain only one photopolymerization initiator (D), or may contain two or more photopolymerization initiators (D).

The photopolymerization initiator (D) is not particularly limited, and examples thereof include oxime (Oxime)-based compounds such as O-hydroxyl oxime compounds, alkylphenone (Alkylphenone) compounds, acylphosphine oxide compounds, and the like.

The O-oxime compound is a compound having a structure represented by the following formula (d). Hereinafter, * represents a bond key.

Examples of O-oxime compounds include: N-benzyloxy-1-(4-phenylhydrogenthiophenyl)butane-1-one-2-imine, N-benzyloxy-1 -(4-Phenylsulfanylphenyl)octane-1-one-2-imine, N-benzyloxy-1-(4-phenylsulfanylphenyl)-3-cyclopentane Propane-1-one-2-imine, N-acetoxy-1-[9-ethyl-6-(2-methylbenzyl)-9H-carbazol-3-yl]ethyl Alkyl-1-imine, N-acetoxy-1-[9-ethyl-6-{2-methyl-4- (3,3-Dimethyl-2,4-dioxocyclopentylmethyloxy)benzyl}-9H-carbazol-3-yl]ethane-1-imine, N-acetyl Oxy-1-[9-ethyl-6-(2-methylbenzyl)-9H-carbazol-3-yl]-3-cyclopentylpropane-1-imine, N-benzyl Ethyloxy-1-[9-ethyl-6-(2-methylbenzyl)-9H-carbazol-3-yl]-3-cyclopentylpropan-1-one-2-imine , N-Acetyloxy-1-[4-(2-hydroxyethyloxy)phenylsulfanylphenyl]propan-1-one-2-imine, N-Acetyloxy- 1-[4-(1-Methyl-2-methoxyethoxy)-2-methylphenyl]-1-(9-ethyl-6-nitro-9H-carbazol-3-yl ) methane-1-imine, etc.

Commercially available products such as Irgacure (trade name) OXE01, OXE02 of the same series, OXE03 of the same series (the above are manufactured by BASF Corporation), N-1919, NCI-930, and NCI-831 (the above are manufactured by ADEKA Corporation) can also be used.

The alkylphenone compound is a compound having a partial structure represented by the following formula (d4) or a partial structure represented by the following formula (d5). In these partial structures, the benzene ring may have a substituent.

Examples of compounds having the structure represented by the formula (d4) include: 2-methyl-2-morpholino-1-(4-methylhydrogenthiophenyl)propan-1-one, 2-dimethylamine Base-1-(4-morpholinylphenyl)-2-benzylbutan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl] -1-[4-(4-morpholinyl)phenyl]butan-1-one, etc.

Commercially available products such as Omnirad (trade name) 369, 907 of the same series, and 379 of the same series (the above are manufactured by IGM Resins B.V.) can also be used.

Examples of compounds having the structure represented by the formula (d5) include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-2-methyl-1-[4-(2- Hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylbenzene ketone, oligomer of 2-hydroxy-2-methyl-1-(4-isopropenylphenyl)propan-1-one, α,α-diethoxyacetophenone, benzyl dimethyl ketal, etc.

Commercially available products such as Omnirad (trade name) 184 (manufactured by IGM Resins B.V.) can also be used.

Examples of the acylphosphine oxide compound include: phenylbis(2,4,6-trimethylbenzyl)phosphine oxide (for example, trade name "Omnirad 819" (manufactured by IGM Resins B.V.), 2,4,6 -Trimethylbenzyldiphenylphosphine oxide, etc.

Further examples of the photopolymerization initiator (D) include:

Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;

Benzophenone, methyl o-benzoic acid benzoate, 4-phenyl diphenyl ketone, 4-benzyl-4'-methyl diphenyl sulfide, 3,3', 4,4'-Tetrakis(tert-butylperoxycarbonyl) diphenyl ketone, 2,4,6-trimethyl diphenyl ketone, 4,4'-bis(N,N'-dimethylamine base)-diphenyl ketone and other diphenyl ketone compounds;

Xanthone compounds such as 2-isopropyl Thioxanthone and 2,4-diethylthioxanthone;

9,10-dimethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10-diethoxyanthracene, etc. Anthracene compounds;

Quinone compounds such as 9,10-phenanthrenequinone, 2-ethyl Anthraquinone and Camphorquinone;

Diphenylethanedione (benzil), methyl phenylglyoxylate, titanocene (Titanocene) compounds, etc.

When the total amount of the adhesive composition is 100% by mass, the content of the photopolymerization initiator (D) is usually 0.1% by mass or more and 20% by mass or less. From the viewpoint of the curability of the adhesive composition and the bonding From the viewpoint of the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer), it is preferably 0.5 mass % or more and 15 mass % or less, particularly preferably 1 mass % or more and 10 mass % or less (for example, 8 mass % or less). .

When the total amount of the (meth)acrylate compound (C) is set to 100 parts by mass, the content of the photopolymerization initiator (D) is usually 0.1 parts by mass or more and 30 parts by mass or less, from the curing of the adhesive composition. From the viewpoint of properties and the adhesiveness of the adhesive composition to the thermoplastic resin film (or layer), it is preferably 0.5 parts by mass or more and 20 parts by mass or less, particularly preferably 1 part by mass or more and 10 parts by mass or less.

[5] Tackifier

The adhesive composition may further contain a tackifier. The tackifier resin is not particularly limited, and generally known ones can be appropriately selected, and examples thereof include rosin derivatives (eg, rosin, polymerized rosin, hydrogenated rosin), terpene-based resins (eg, terpene resin, aromatic modified rosin) Terpene resin, terpene phenol resin, hydrogenated terpene resin), petroleum resin, phenol resin, xylene resin, etc.

Among them, the adhesive composition preferably further contains the petroleum resin (E). By making the adhesive composition further contain the petroleum resin (E), the adhesiveness can be improved, and the moisture permeability of the cured film formed from the adhesive composition can be reduced.

The adhesive composition capable of forming a cured film with low moisture permeability is suitable for applications that require the prevention of water ingress and egress through the cured film. For example, in a polarizer in which a thermoplastic resin film is laminated on at least one side of a polarizer with an adhesive layer interposed therebetween, or an image display panel including the polarizer, if the adhesive layer has low moisture permeability, the The ingress and egress of moisture causes the polarizing plate or image display panel to curl (warp).

When the adhesive composition further contains the petroleum resin (E), it is also beneficial to improve the adhesion between the polarizer and the thermoplastic resin film.

The petroleum resin (E) includes an aromatic petroleum resin, an aliphatic petroleum resin, a cycloaliphatic petroleum resin, an aliphatic-aromatic petroleum resin, a dihydrochroman (Chroman)-based resin, and the like. Moreover, what hydrogenated these resin, etc. are also mentioned.

The aromatic petroleum resin is a resin containing one or two or more kinds of structural units derived from aromatic hydrocarbons, and may be hydrogenated or modified.

The aromatic-based petroleum resin is preferably a C9-based petroleum resin. The C9-series petroleum resin is a resin obtained by copolymerizing a C9 fraction, and may be hydrogenated or modified.

The C9-based petroleum resin may be a resin obtained by copolymerizing a C9 fraction and other monomer components, or may be a hydrogenated resin or a modified resin. Other monomer components include C5 fractions.

Examples of the C9 fraction include petroleum fractions having about 8 to 10 carbon atoms, such as styrene, alkylstyrene, vinyltoluene, 1-methyl-1-phenylethylene, indene, and methyl indene.

Examples of the C5 fraction include petroleum fractions having about 4 to 5 carbon atoms, such as cyclopentadiene, pentene, pentadiene, isoprene, and 1,3-pentadiene (Piperylene).

Further, the petroleum resin (E) may be a C5-based petroleum resin obtained by copolymerizing the above-mentioned C5 fraction, a hydrogenated C5-based petroleum resin, or a modified resin. Furthermore, it may be an alicyclic hydrocarbon-based resin in which the C5 fraction is cyclodimerized and then polymerized. The alicyclic hydrocarbon-based resin includes, for example, a polymer containing a structural unit derived from dicyclopentadiene.

The weight-average molecular weight of the petroleum resin (E) is usually 500 or more and 10,000 or less, from the viewpoint of reducing the moisture permeability of the cured film formed from the adhesive composition and the adhesive composition for thermoplastics. From the viewpoint of the adhesiveness of the resin film (or layer), it is preferably 500 or more and 7000 or less, more preferably 600 or more and 5000 or less, more preferably 600 or more and 3000 or less.

The weight average molecular weight of the petroleum resin (E) can be measured as a standard polystyrene conversion value obtained by gel permeation chromatography (GPC).

In the case where the adhesive composition contains the petroleum resin (E), when the total amount of the adhesive composition is set to 100% by mass, the content of the petroleum resin (E) is reduced from reducing the amount of the petroleum resin (E) formed by the adhesive composition. From the viewpoint of the moisture permeability of the cured film and the adhesion of the adhesive composition to the thermoplastic resin film (or layer), especially in the case of using a polyvinyl alcohol-based polarizer as the polarizer, it is necessary to improve the polyvinyl alcohol-based polarizer. From the viewpoint of the adhesion between the polarizer and the thermoplastic resin film, it is preferably 20% by mass or more and 70% by mass or less, and particularly preferably 30% by mass or more and 65% by mass or less.

The moisture permeability of the cured film formed from the adhesive composition is preferably low. The cured film with a thickness of 10 μm composed of the adhesive composition, the moisture permeability measured by the moisture permeable cup method stipulated in JIS Z 0208 and at a temperature of 40 ° C and a relative humidity of 90% is preferably 400 g/(m ² .24 hr) or less, more preferably 300 g/(m ² .24 hr) or less, more preferably 200 g/(m ² .24 hr) or less. The water vapor transmission rate is usually 1 g/(m ² .24hr) or more, for example, 5 g/(m ² .24hr) or more.

Regarding the water vapor transmission rate J of the cured film composed of the adhesive composition, specifically, a laminate in which the cured film is formed on a base film whose water vapor transmission rate is known can be produced, and the laminate can be measured according to the method described above. The water vapor transmission rate of the body was determined according to the following formula using the measurement results.

1/Jt=(1/J)+(1/Jsub)

In the above formula, Jt is the water vapor transmission rate of the laminate, and Jsub is the water vapor transmission rate of the base film. As a base film, the same thing as the thermoplastic resin film mentioned later can be used. When the moisture permeability of the laminated body is measured according to JIS Z 0208, the laminated system is attached to the moisture permeable cup so that the above-mentioned cured film faces the outside.

Regarding the above-mentioned layered product, for example, when a (meth)acrylic resin film having a thickness of 60 μm is used as the above-mentioned base film, the thickness of the (meth)acrylic resin film and the adhesive composition is 10 μm . The laminated body of the cured film, the moisture permeability measured by the moisture permeable cup method specified in JIS Z 0208 and under the conditions of temperature 40°C and relative humidity 90% is preferably 55g/(m ² .24hr) or less , preferably 50g/(m ² .24hr) or less. The water vapor transmission rate is usually 1 g/(m ² .24hr) or more, for example, 5 g/(m ² .24hr) or more.

[6] Other ingredients

The adhesive composition may contain other components than the above-mentioned components.

Examples of other components include curable components other than the (meth)acrylate compound (C), crosslinking agents, and additives such as coupling agents, antioxidants, ultraviolet absorbers, and thermal stabilizers.

[7] Viscosity of adhesive composition

The viscosity of the agent composition at 25°C is preferably 10000mPa. sec or less, preferably 2mPa. sec above 7000mPa. sec or less, more preferably 300mPa. 5000mPa above sec. sec or less.

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

<Polarizer>

The above-mentioned adhesive composition of the present invention is suitable for the bonding of thermoplastic resin films, and can be used, for example, for lamination of thermoplastic resin films and other thermoplastic resin films (or layers). One application example of the adhesive composition of the present invention is for polarizing plates, that is, it can be used to make polarizing plates. More specifically, the adhesive composition of the present invention can be used as an adhesive composition for laminating a "polarizer" and a "thermoplastic resin film like a protective film laminated on the polarizer".

The polarizing plate of the present invention includes a polarizer, and a thermoplastic resin film laminated on at least one side of the polarizer via an adhesive layer formed of the adhesive composition. The said adhesive agent layer is the hardened|cured material layer of the said adhesive agent composition.

Since the polarizing plate of the present invention uses the above-mentioned adhesive composition to bond the polarizing plate and the thermoplastic resin film, the adhesion between the polarizing plate and the thermoplastic resin film can be improved, and the wet heat durability of the polarizing plate can be improved. Sex becomes better. That is, according to the present invention, it is possible to provide a polarizing plate having good adhesion between the polarizer and the thermoplastic resin film even after being placed in a humid and heat environment.

The polarizing plate of the present invention can be suitably used in image display devices such as liquid crystal display devices and organic EL devices.

[1] Composition of polarizing plate

The example of the layer structure of the polarizing plate of this invention is shown in FIG.1 and FIG.2.

As shown in FIG. 1 , the polarizer of the present invention may include a polarizer 30 , a first adhesive layer 15 and a first thermoplastic resin film 10 in sequence, that is, a polarizer 30 , and a polarizer 30 on one side of the polarizer 30 . The first thermoplastic resin film 10 which is laminated and bonded with the first adhesive layer 15 interposed therebetween.

The first adhesive layer 15 and the first thermoplastic resin film 10 are preferably in direct contact with each other.

The polarizer 30 and the first adhesive layer 15 are preferably in direct contact with each other.

In addition, as shown in FIG. 2 , the polarizing plate of the present invention may also include: a polarizer 30, a first thermoplastic resin film 10 laminated and bonded on one side of the polarizer 30 via the first adhesive layer 15, and On the other surface of the polarizer 30, the 2nd thermoplastic resin film 20 laminated|stacked via the 2nd adhesive agent layer 25 is laminated|stacked.

The first adhesive layer 15 and the first thermoplastic resin film 10 are preferably in direct contact with each other.

The polarizer 30 and the first adhesive layer 15 are preferably in direct contact with each other.

The second adhesive layer 25 and the second thermoplastic resin film 20 are preferably in direct contact with each other.

The polarizer 30 and the second adhesive layer 25 are preferably in direct contact with each other.

When the polarizing plate has the first adhesive layer 15 and the second adhesive layer 25, either one may be formed of the adhesive composition of the present invention, or both adhesive layers may be formed of the present invention. Then the agent composition is formed. The adhesive layer formed from the adhesive composition of the present invention is preferably the adhesive layer on the viewing side (the adhesive layer farther from the pressure-sensitive adhesive layer described later).

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

Not limited to the examples of FIG. 1 and FIG. 2 , the polarizing plate of the present invention may include other layers (or films) other than those described above. Other layers include, for example: the 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; the separation film ( Also referred to as "release film"); a protective film (also referred to as "surface protective film") laminated on the outer surfaces of the first thermoplastic resin film 10, the second thermoplastic resin film 20 and/or the polarizer 30; 1. An optically functional film (or layer) or the like laminated on the outer surfaces of the thermoplastic resin film 10, the second thermoplastic resin film 20 and/or the polarizer 30 with an adhesive layer or an adhesive layer interposed therebetween.

[2] Polarizer

The polarizer 30 is a film having "the function of selectively transmitting linearly polarized light in a certain direction from natural light". Examples of the polarizer 30 include: an iodine-based polarizer in which iodine as a dichroic dye is adsorbed and aligned on a polyvinyl alcohol-based resin film; A dye-based polarizer; and a coating-type polarizer obtained by coating, aligning and immobilizing a dichroic dye in a lyotropic liquid crystal state. These polarizers are derived from In natural light, the linearly polarized light in one direction selectively penetrates and absorbs the linearly polarized light in the other direction, so it is called an absorption polarizer.

The polarizer 30 is not limited to an absorbing polarizer, and can also be a reflective polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects linearly polarized light in another direction, or a reflective polarizer that allows linearly polarized light in another direction. A scattering-type polarizer that scatters linearly polarized light, but an absorption-type polarizer is preferred from the viewpoint of excellent visibility when the polarizing plate is applied to an image display device or the like.

Among them, the polarizer 30 is preferably a polyvinyl alcohol-based polarizer composed of a polyvinyl alcohol-based resin, and more preferably a polyethylene that adsorbs and aligns dichroic dyes such as iodine or dichroic dyes on the polyvinyl alcohol-based resin film The alcohol-based polarizer is particularly preferably a polyvinyl alcohol-based polarizer in which iodine is adsorbed and aligned on a polyvinyl alcohol-based resin film.

The polyvinyl alcohol-based polarizer can be produced by a conventionally known method using a polyvinyl alcohol-based resin film (or layer).

The thickness of the polarizer 30 can be set to 30 μm or less, preferably 25 μm or less (for example, 20 μm or less, especially 15 μm or less, especially 10 μm or less, especially 8 μm or less). The thickness of the polarizer 30 is usually 2 μm or more. If the thickness of the polarizer 30 is reduced, it is advantageous to reduce the thickness of the polarizer and the image display device using the polarizer.

[3] Thermoplastic resin film

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may each be a film made of a thermoplastic resin having light transmittance (preferably optically transparent), and the thermoplastic resin may be, for example, a chain polyolefin resin Polyolefin-based resins such as polyethylene resins, polypropylene-based resins, etc., cyclic polyolefin-based resins (norbornene-based resins, etc.); cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; Polyester resins such as ethylene phthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resins; (meth)acrylic resins; or mixtures and copolymers of these Wait.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be any of an unstretched film and a uniaxially or biaxially stretched film, respectively. Biaxial stretching may be simultaneous biaxial stretching in two stretching directions, or sequential biaxial stretching in which stretching is performed in a first direction and then in a second direction different from it. stretch.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be a protective film responsible for protecting the polarizer 30, or may be a protective film having optical functions such as retardation films.

For example, by stretching (uniaxial stretching, biaxial stretching, etc.) a film composed of the thermoplastic resin, or forming a liquid crystal layer on the thermoplastic resin film, it is possible to provide an arbitrary retardation value. The retardation film.

The (meth)acrylic resin may be, for example, a polymer containing methacrylate as a main monomer (containing 50% by mass or more), and preferably a copolymer obtained by copolymerizing methacrylate and other copolymerization components.

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

Examples of other copolymerization components other than methyl acrylate include the following monofunctional monomers: ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate or tert-butyl methacrylate, methacrylic acid Methacrylates other than methyl methacrylate, such as cyclohexyl ester, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate;

Acrylic acid such as ethyl acrylate, n-butyl acrylate, isobutyl acrylate or tert-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, etc. esters;

Methyl 2-(hydroxymethyl)acrylate, methyl 2-(1-hydroxyethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, n-butyl 2-(hydroxymethyl)acrylate, 2-( Hydroxyalkyl acrylates such as isobutyl hydroxymeth)acrylate or tert-butyl 2-(hydroxymeth)acrylate;

Unsaturated acids such as methacrylic acid and acrylic acid;

Halogenated styrenes such as chlorostyrene and bromostyrene;

Substituted styrenes such as vinyltoluene, α -methylstyrene;

Unsaturated nitriles such as acrylonitrile and methacrylonitrile;

Unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride;

Unsaturated imides such as phenylmaleimide, cyclohexylmaleimide, etc.

The other monofunctional monomers mentioned above may be used alone or in combination of two or more.

A polyfunctional monomer can also be used for the other copolymerization components mentioned above.

Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. base) acrylate, nonaethylene glycol di(meth)acrylate, tetradecylethylene glycol di(meth)acrylate, etc. The hydroxyl groups at both ends of ethylene glycol or its oligomers are treated with (meth)acrylic acid esterifier;

The two terminal hydroxyl groups of propylene glycol or its oligomers are esterified with (meth)acrylic acid;

Neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, butanediol di(meth)acrylate, etc. which esterified the hydroxyl group of dihydric alcohol with (meth)acrylic acid ;

The two terminal hydroxyl groups of bisphenol A, alkylene oxide adducts of bisphenol A or these halogen substitution products are esterified with (meth)acrylic acid;

Esterification of polyhydric alcohols such as trimethylolpropane and neotaerythritol with (meth)acrylic acid, and ring-opening addition of epoxy groups of glycidyl (meth)acrylate to their terminal hydroxyl groups By;

For dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, halogen-substituted products of these, or their alkylene oxide adducts, etc., glycidyl (meth)acrylate Epoxy group undergoes ring-opening addition;

Aromatic divinyl compounds such as (meth)acrylates; divinylbenzene and the like.

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

The (meth)acrylic resin may be modified by the reaction between the functional groups which the copolymer has. The reaction may include, for example, the demethanol condensation reaction in the polymer chain between the methyl group of methyl (meth)acrylate and the hydroxyl group of 2-(hydroxymethyl)acrylate, and the carboxyl group of (meth)acrylic acid and 2 -Dehydration condensation reaction of the hydroxyl group of methyl (hydroxymeth)acrylate in the polymer chain, etc.

The glass transition temperature of the (meth)acrylic resin is preferably 80°C or higher and 160°C or lower. The glass transition temperature can be determined by the polymerization ratio of methacrylate-based monomer and acrylate-based monomer, the carbon chain length of each ester group, the kind of functional group they have, and the relative ratio of polyfunctional monomer to monofunctional monomer. It can be controlled by adjusting the polymerization ratio of the whole body.

Regarding the means for increasing the glass transition temperature of the (meth)acrylic resin, "introduction of a ring structure into the main chain of the polymer" is also effective. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure, and a lactone structure. Specifically, cyclic acid anhydride structures such as glutaric anhydride structures and succinic anhydride structures; cyclic imide structures such as glutarimide structures and succinimidyl structures; lactones such as butyrolactone and valerolactone include ring structure.

As the content of the ring structure in the main chain increases, the glass transition temperature of the (meth)acrylic resin tends to increase.

The cyclic acid anhydride structure and the cyclic imide structure can be introduced by the following methods: a method of copolymerizing monomers having a cyclic structure such as maleic anhydride and maleimide; A method of introducing a cyclic acid anhydride structure by dehydration and demethanol condensation reaction after polymerization; a method of introducing a cyclic imide structure by reacting an amine compound, and the like.

A resin (polymer) having a lactone ring structure can be obtained by the following method: after preparing a polymer having a hydroxyl group and an ester group in the polymer chain, it is heated, and if necessary, is contacted with an organophosphorus compound or the like. In the presence of a medium, the hydroxyl group and the ester group in the obtained polymer are cyclized and condensed to form a lactone ring structure.

An additive may be contained in the 1st thermoplastic resin film 10 and the 2nd thermoplastic resin film 20 as needed. As an additive, a slip agent, an anti-caking agent, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, an impact resistance improver, a surfactant, etc. are mentioned, for example.

The (meth)acrylic resin may contain acrylic rubber particles as an impact modifier from the viewpoints of film formability to a film, impact resistance of the film, and the like. The so-called acrylic rubber particles refer to particles that have an elastic polymer mainly composed of acrylic ester as an essential component, and examples include those having substantially only a single-layer structure composed of this elastic polymer, or those having an elastic polymerized thing as a multilayer structure of one of the layers.

As an example of the said elastic polymer, the crosslinked elastic copolymer which uses an alkyl acrylate as a main component, and copolymerizes other vinylic monomers and crosslinkable monomers which can be copolymerized with this can be mentioned.

Examples of the alkyl acrylate to be the main component of the elastic polymer include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like, and the carbon number of the alkyl group is about 1 or more and 8 or less, preferably An alkyl acrylate having an alkyl group having 4 or more carbon atoms is used.

Examples of other vinyl-based monomers that can be copolymerized with the above-mentioned alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid such as methyl methacrylate and the like can be mentioned. Esters; aromatic vinyl compounds such as styrene; vinyl cyanide compounds such as acrylonitrile, etc.

Examples of the crosslinkable monomers include compounds having crosslinkability of at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di(meth)acrylate, butylene glycol (meth)acrylates of polyhydric alcohols such as alcohol di(meth)acrylate; alkenyl esters of (meth)acrylic acid such as allyl (meth)acrylate; divinylbenzene and the like.

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

In the case where the thermoplastic resin film is a (meth)acrylic resin film, the adhesive composition of the present invention can express particularly good adhesion. Therefore, the adhesive composition of this invention can be suitably used for the bonding of a polarizer and a (meth)acrylic-type resin film.

In the (meth)acrylic resin film, it is preferable that the resin component is composed of a (meth)acrylic resin.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be films made of the same thermoplastic resin or films made of mutually different thermoplastic resins. The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be the same or different in terms of thickness, the presence or absence of additives or their types, 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-based resin film (preferably a cyclic polyolefin-based resin film), cellulose Ester resin or polyester resin film.

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

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may also have a hard coat layer, an anti-glare layer, an anti-reflection layer, a light-diffusing layer, an anti-reflection layer on the outer surface (the surface opposite to the polarizer 30 ) Surface treatment layer (coating layer) such as electrostatic layer, antifouling layer, conductive layer, etc.

The thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 are usually 5 μm or more and 200 μm or less, preferably 10 μm or more and 120 μm or less, and particularly preferably 10 μm or more and 85 μm or less. , more preferably 15 μm or more and 65 μm or less. The thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be 50 μm or less, respectively, or 40 μm or less. When the thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 are reduced, it is advantageous to reduce the thickness of the polarizing plate and the image display device using the polarizing plate.

From the viewpoint of improving adhesion, saponification treatment, plasma treatment, corona treatment, and primer treatment can be performed on the surfaces of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 to which the adhesive composition is applied. and other surface modification treatment.

[4] Manufacture of polarizing plate and adhesive layer

By laminating and adhering the first thermoplastic resin film 10 on one surface of the polarizer 30 via the first adhesive layer 15, the polarizing plate having the structure shown in FIG. The second thermoplastic resin film 20 is further laminated with the second adhesive layer 25 interposed therebetween, whereby a polarizing plate having the configuration shown in FIG. 2 can be obtained.

When manufacturing a polarizing plate having both the first thermoplastic resin film 10 and the second thermoplastic resin film 20 (hereinafter, these are also collectively referred to only as "thermoplastic resin films"), these thermoplastic resin films may be one-sided in a stepwise manner. The lamination and bonding may be performed simultaneously, and the thermoplastic resin films on both sides may be simultaneously laminated and bonded.

In the polarizing plate of the configuration shown in FIG. 1 , the first adhesive layer 15 is formed of the adhesive composition of the present invention. The first adhesive layer 15 is a cured product layer of the adhesive composition of the present invention.

In the polarizing plate of the structure shown in FIG. 2, at least any one of the 1st adhesive agent layer 15 and the 2nd adhesive agent layer 25 is formed of the adhesive agent composition of this invention. The first adhesive layer 15 and/or the second adhesive layer 25 are cured layers of the adhesive composition of the present invention.

In the polarizing plate with the structure shown in FIG. 2, either one of the first adhesive layer 15 and the second adhesive layer 25 may be formed of the adhesive composition of the present invention, and the other may be formed of the adhesive composition of the present invention. The adhesive composition of the present invention is formed from other adhesive compositions different from the adhesive composition of the present invention.

As the other adhesive composition, conventionally known water-based adhesives or active energy ray-curable adhesives can be exemplified.

The water-based adhesive includes, for example, a conventionally known adhesive composition using a polyvinyl alcohol-based resin or a urethane resin as a main component.

Active energy ray-curable adhesives are adhesives that are cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. When an active energy ray-curable adhesive is used, the adhesive layer included in the polarizing plate is a cured product layer of the adhesive.

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

Examples of epoxy-based compounds include hydrogenated epoxy-based compounds (glycidyl ethers of polyols having alicyclic rings), which are obtained by hydrogenating the aromatic rings of aromatic polyols to obtain alicyclic compounds. Polyol, which is obtained by reacting epichlorohydrin with the alicyclic polyol; aliphatic epoxy compounds, which are polyglycidyl ethers of aliphatic polyols or their alkylene oxide adducts, etc. Alicyclic epoxy-based compounds, which are epoxy-based compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule, and the like.

In the active energy ray-curable adhesive, as a curable component, a "radical polymerizable (meth)acrylic compound" may be contained in place of "the above-mentioned epoxy compound", or an "epoxy compound" may be contained simultaneously. series compounds" and "radical polymerizable (meth)acrylic compounds". Examples of the (meth)acrylic-based compound include (meth)acrylate monomers having one or more (meth)acryloyloxy groups in the molecule, and those obtained by reacting two or more functional group-containing compounds, And a (meth)acryloyloxy group-containing compound, such as a (meth)acrylate oligomer which has at least 2 (meth)acryloyloxy groups in a molecule|numerator.

In the active energy ray-curable adhesive agent, when an epoxy-based compound that can be cured by cationic polymerization is contained as a curable component, it is preferable to contain a photocationic polymerization initiator. Examples of the photocationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic peronium salts; iron-aromatic complexes and the like.

In the active energy ray-curable adhesive, when a radical polymerizable component such as a (meth)acrylic compound is contained, it is preferable to contain a photoradical polymerization initiator. Examples of photo-radical polymerization initiators include acetophenone-based initiators, benzophenone-based initiators, benzoin ether-based initiators, thioxanthone-based initiators, xanthone-based initiators, and Ketone (Fluorenone), camphorquinone, benzaldehyde (Benzaldehyde), anthraquinone, etc.

The bonding between the polarizer 30 and the thermoplastic resin film may include the following steps: coating the adhesive composition on the bonding surface of the polarizer 30 and/or the bonding surface of the thermoplastic resin film, or forming an adhesive composition A substance is injected between the polarizer 30 and the thermoplastic resin film, and the two films are superimposed with the layer of the adhesive composition interposed therebetween, and are bonded by pressing from above and below using, for example, a bonding roller.

For the formation of the adhesive composition layer, various coating methods such as a doctor blade, a wire rod, a die coater, a comma coater, and a gravure coater can be applied. In addition, a method of continuously supplying the polarizer 30 and the thermoplastic resin film so that the bonding surfaces of both are inside, and casting the adhesive composition therebetween may be employed.

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

When an active energy ray-curable adhesive is used, an active energy ray is irradiated to harden the adhesive composition layer.

The light source for irradiating the active energy rays may be any one that can generate ultraviolet rays, electron beams, X-rays, and the like. Especially suitable for use: low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, etc.

The thickness of the adhesive layer formed by the adhesive composition of the present invention is, in the polarizing plate, for example, 0.1 μm or more and 100 μm or less, preferably 0.5 μm or more and 80 μm or less, particularly preferably 1 μm . 60 μm or less, more preferably 2 μm or more and 50 μm or less. From the viewpoint of reducing the thickness of the polarizing plate, the thickness of the adhesive layer is preferably 30 μm or less, and more preferably 20 μm or less.

The thicknesses of the first adhesive layer 15 and the second adhesive layer 25 may be the same or different.

[5] Other components of polarizing plate

[5-1] Optical functional film

The polarizing plate may be provided with other optical functional films other than the polarizing plate 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 retardation film, but a retardation film may be separately laminated in addition to the thermoplastic resin film. In the latter case, the retardation film may be laminated on the outer surface of the first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 via an adhesive layer or an adhesive layer.

The retardation film includes: a birefringent film composed of a stretched film of a light-transmitting thermoplastic resin; a film in which a discotic liquid crystal or a nematic liquid crystal is fixed in alignment; a substrate film The above-mentioned liquid crystal layer is formed thereon, and the like.

The base film is usually a film made of a thermoplastic resin, and an example of the thermoplastic resin is a cellulose ester resin such as cellulose triacetate.

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 optically functional films (optical members) that can be included in the polarizing plate include a light-collecting plate, a brightness enhancement film, a reflection layer (reflection film), a transflective layer (transflective film), a light diffusion layer (light diffuser), etc. These are generally set when "the polarizing plate is a polarizing plate arranged on the back side (backlight side) of the liquid crystal cell".

[5-2] Adhesive layer

The polarizing plate of the present invention may include an adhesive layer for attaching the polarizing plate to image display elements such as liquid crystal cells, organic EL elements, or other optical members. In the polarizer with the configuration shown in Figure 1, the adhesive The adhesive layer can be laminated on the outer surface of the polarizer 30 , and in the polarizer with the configuration shown in FIG. 2 , the adhesive layer can be laminated on the outer surface of the first thermoplastic resin film 10 or the second thermoplastic resin film 20 .

The adhesive used in the adhesive layer can be: (meth)acrylic resin or polysilicone resin, polyester resin, polyurethane resin, polyether resin, etc. base polymer. Among them, from the viewpoints of transparency, adhesive strength, reliability, weather resistance, heat resistance, reworkability, and the like, (meth)acrylic-based adhesives are preferred.

The thickness of the adhesive layer is determined according to the adhesive force and the like, and is preferably in the range of 1 μm or more and 50 μm or less, preferably 2 μm or more and 40 μm or less.

The polarizing plate may include a separation film laminated on the outer surface of the adhesive layer. The separation membrane may be a membrane composed of polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, polyester-based resins such as polyethylene terephthalate, and the like. Among them, a stretched film of polyethylene terephthalate is preferred.

The adhesive layer may optionally contain glass fibers, glass beads, resin beads, fillers composed of metal powder or other inorganic powders, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents, and the like.

[5-3] Protective film

The polarizing plate of the present invention may include a protective film for protecting its surface (thermoplastic resin film surface or polarizer surface, etc.). For example, after the polarizing plate is attached to the image display element or other optical components, the protective film will be peeled off together with the adhesive layer it has.

The protective film is composed of, for example, a base film and an adhesive layer laminated on the base film. Regarding the adhesive layer, the above description can be cited.

The resin constituting the base film may be, for example, a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, and a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate. , Polycarbonate resins and other thermoplastic resins. Polyester resins, such as polyethylene terephthalate, are preferable.

[Example]

The following series of examples are shown to illustrate the present invention more specifically, but the present invention is not limited to these examples. In the example, the % and part indicating the content and the amount of use are the quality standards unless otherwise specified. The thickness of the film and the adhesive layer (cured film) was measured using a digital micrometer "MH-15M" manufactured by Nikon Co., Ltd.

<Example 1>

(1) Preparation of curable adhesive composition

The components shown in Table 1 were mixed in the compounding amounts shown in Table 1, and the curable adhesive composition A was prepared. The unit of the compounding quantity of each component shown in Table 1 is a mass part.

The details of each component shown in Table 1 are as follows.

(A): Maleic anhydride-modified liquid polybutadiene (trade name "Lithene ultra N4-B-10MA" manufactured by Synthomer, number average molecular weight: 8200, viscosity at 25°C: 60 to 90 Pa. sec, acid value: 54KOHmg/g)

(Ba): Unmodified liquid polybutene (trade name "Nichiyu Polybutene Emawet 0N" manufactured by NOF Corporation, number average molecular weight: 370)

(Bb): Unmodified liquid polybutene (trade name "Nichiyu Polybutene Emawet 015N" manufactured by NOF Corporation, number average molecular weight: 580)

(C-1a): Dicyclopentyl acrylate (trade name "FA-513AS" manufactured by Hitachi Chemical Co., Ltd.)

(C-1b): Isostearyl acrylate (trade name "S-1800A" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

(C-2): Ethoxylated bisphenol A diacrylate (trade name "A-BPE-10" manufactured by Shin-Nakamura Chemical Industry Co., Ltd., EO 10 moles)

(D): Phenylbis(2,4,6-trimethylbenzyl)phosphine oxide (trade name "Omnirad 819" manufactured by IGM Resins B.V.)

(E): Petroleum resin (trade name "T-REZHA105" manufactured by JXTG Energy Co., Ltd., hydrogenated resin (alicyclic saturated hydrocarbon resin containing dicyclopentadiene as a monomer component), softening point (nominal value) ): 104.5°C, weight average molecular weight (nominal value): 610)

(2) Production of polarizing plate

After corona treatment was applied to the surface of a polymethyl methacrylate (PMMA: Polymethyl Methacrylate) film with a thickness of 60 μm , the hardening prepared in the above (1) was applied to the corona treated surface using an adhesive coating device. Adhesive composition A. The obtained coating layer and a polyvinyl alcohol-iodine-based polarizer having a thickness of 23 μm were laminated using a roll to obtain a polarizer with a PMMA film.

Next, after corona treatment was applied to the surface of a retardation film with a thickness of 50 μm (trade name “ZEONOR”, manufactured by Zeon Japan Co., Ltd.] composed of a cyclic polyolefin resin, the corona treated surface was treated with corona. The curable adhesive composition B prepared in accordance with the following description was applied using an adhesive coating apparatus. The obtained coating layer and the polarizer surface of the PMMA film-attached polarizer were laminated using a roll to obtain a laminated body. From the retardation film side of the laminated body, the total cumulative light amount (the cumulative amount of light irradiation intensity in the wavelength region of 320 to 400 nm) is about 200 mJ/cm ² (by measuring device: UV manufactured by Fusion UV Co., Ltd.) The measurement value obtained by Power PuckII) ultraviolet (UVB), by this, the layer of curable adhesive composition B and the layer of curable adhesive composition A were hardened, and the polarizing plate was produced. The thickness of the hardened layer of the curable adhesive composition A was about 10 μm , and the thickness of the hardened layer of the curable adhesive composition B was about 2.5 μm .

The curable adhesive composition B was prepared as follows: 3',4'-epoxycyclohexylmethyl ester (trade name made by Daicel Co., Ltd.) with respect to 3,4-epoxycyclohexanecarboxylic acid "Celloxide 2021P") 100 parts by mass, 25 parts by mass of 1,4-butanediol diglycidyl ether (trade name "EX-214L" manufactured by Nagase Chemtex Co., Ltd.) and a photopolymerization initiator (Sun Apro Co., Ltd.) were added Co., Ltd. product name "CPI-100P") 5.6 parts by mass and mixed.

<Examples 2 to 9, Comparative Example 1>

The curable adhesive composition A was prepared in the same manner as in Example 1, except that the compounding amounts of the compounding components were changed to those shown in Table 1. Further, a polarizing plate was produced in the same manner as in Example 1 except that this curable adhesive composition A was used.

<Measurement and Evaluation>

(1) Moisture permeability of cured film formed from curable adhesive composition A

Curable adhesive composition A was applied to a PMMA film having a thickness of 60 μm after corona treatment was applied using an adhesive coating apparatus.

On the coating layer of the curable adhesive composition A, an untreated polyethylene terephthalate (PET:Polyethylene Terephthalate) film was laminated, and bonded using a roll. Next, the total cumulative light amount of irradiation (the cumulative amount of light irradiation intensity in the wavelength region of 320 to 400 nm) is about 200 mJ/cm ² (measured value by measuring device: UV Power Puck II manufactured by Fusion UV Co., Ltd.) Ultraviolet rays (UVB) were used to harden the adhesive layer to obtain a laminate having a layer configuration of PMMA film/hardened adhesive layer/PET film. Then, the PET film was peeled off to obtain a laminate (sample for moisture permeability measurement) having a layer structure of a PMMA film/cured adhesive layer (cured film).

For the obtained laminate (sample for moisture permeability measurement), the moisture permeability [g/(m ² .24hr) at a temperature of 40°C and a relative humidity of 90% was measured by the moisture permeability cup method specified in JIS Z 0208. ]. Incidentally, at the time of the measurement, the cured adhesive layer (cured film) in the above-mentioned laminate was placed in an environment of a temperature of 40° C. and a relative humidity of 90%. Moreover, the laminated system is attached to the moisture-permeable cup so that the cured film may face the outside.

The results are shown in the column of "moisture permeability of the laminate" in Table 1. The numerical system in parentheses shows the thickness (unit: μm ) of the cured film which the laminated body has.

Moreover, using the water vapor transmission rate (Jt) of the obtained laminated body, the water vapor transmission rate (J) in temperature 40 degreeC and relative humidity 90% of the cured film itself was calculated|required from the following formula.

1/Jt=(1/J)+(1/Jsub)

The PMMA film with a thickness of 60 μm as the base film, the moisture permeability (Jsub) measured by the moisture permeable cup method specified in JIS Z 0208 under the conditions of a temperature of 40° C. and a relative humidity of 90% is 70 g/(m ² .24hr).

The results are shown in the column of "Moisture permeability of cured film" in Table 1. The numerical system in parentheses represents the thickness (unit: μm ) of the cured film.

(2) Evaluation of the adhesion between the polarizer and the PMMA film in the polarizer (initial stage)

An adhesive layer was formed on the PMMA film side of the obtained polarizing plate. The polarizing plate with the obtained adhesive layer was cut into a size of 200 mm in length (parallel to the absorption axis direction of the polarizer)×25 mm in width, and the adhesive layer was bonded to a glass plate to obtain a laminate. The obtained laminate was used as a test piece for measuring the peel strength between the polarizer and the PMMA film. Insert the blade of the cutter between the polarizer and the PMMA film of the test piece, peel off 30 mm from the end in the longitudinal direction, and pick up the peeled part with the gripping part of the tester, and the gripping part sandwiches the glass plate. . For the test piece in this state, in an environment with a temperature of 23°C and a relative humidity of 55%, the test was conducted in accordance with JIS K 6854-2: 1999 "Adhesives - Test Method for Peeling Adhesion Strength" -Part 2: 180-degree peeling", the peeling test was carried out at a gripping moving speed of 300 mm/min, and the average peeling force covering a length of 170 mm excluding 30 mm of the gripping portion was obtained, which was used as the polarizer and the PMMA film. peel strength between. The results are shown in Table 1. The peeling strength was measured after making a polarizing plate and leaving it to stand in an environment with a temperature of 23° C. and a relative humidity of 50% RH for 24 hours.

In Table 1, the so-called "broken" means that the peeling strength is extremely high, and the PMMA film or the polarizer is broken before the film is peeled off. In Comparative Example 1, the adhesion between the polarizer and the PMMA film was too weak to measure the peel strength.

(3) Evaluation of the adhesion between the polarizer in the polarizer and the PMMA film (after exposure to a high temperature and high humidity environment)

An adhesive layer was formed on the PMMA film side of the obtained polarizing plate. The obtained polarizing plate with the adhesive layer was cut into a size of 200 mm in length (parallel to the absorption axis direction of the polarizer)×25 mm in width, and the adhesive layer was bonded to glass to obtain a laminate. The obtained laminate was left to stand for 24 hours in a high temperature and high humidity environment with a temperature of 80°C and a relative humidity of 90% RH, and then was left in an environment with a temperature of 23°C and a relative humidity of 50% RH for 24 hours. Then, the blade of the cutter was inserted between the polarizer and the PMMA film of the obtained laminate, and 30 mm was peeled from the end in the longitudinal direction. Attached to the glass plate. For the test piece in this state, in an environment with a temperature of 23°C and a relative humidity of 55%, according to JIS K 6854-2: 1999 "Adhesives - Test Method for Peeling Adhesive Strength - Part 2: Peeling at 180 Degrees" The peeling test was performed at a moving speed of 300 mm/min, and the average peeling force covering the length of 30 mm excluding the nip portion covering 170 mm was obtained as the peeling strength between the polarizer and the PMMA film. The results are shown in Table 1.

[Table 1]

<Example 10>

(1) Preparation of curable adhesive composition

The components shown in Table 2 were mixed with the compounding quantity shown in Table 2, and the curable adhesive composition C was prepared. The unit of the compounding quantity of each component shown in Table 2 is a mass part.

The details of each component shown in Table 2 are as follows.

(Ab): maleic anhydride-modified liquid polybutadiene (trade name "Lithene ultra N4-5000-10MA" manufactured by Synthomer, number average molecular weight: 5500, viscosity at 25°C: 25 to 60Pa. sec, acid value: 54KOHmg/g)

(Bb): Unmodified liquid polybutene (trade name "Nichiyu Polybutene Emawet 015N" manufactured by NOF Corporation, number average molecular weight: 580)

(C-1a): Dicyclopentyl acrylate (trade name "FA-513AS" manufactured by Hitachi Chemical Co., Ltd.)

(C-1b): Isostearyl acrylate (trade name "S-1800A" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

(C-1c): Stearyl acrylate (trade name "A-S" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

(C-1d): Lauryl Acrylate (trade name "LA", manufactured by Osaka Organic Chemical Industry Co., Ltd.)

(C-2): Ethoxylated bisphenol A diacrylate (trade name "A-BPE-10" manufactured by Shin-Nakamura Chemical Industry Co., Ltd., EO 10 moles)

(D): Phenylbis(2,4,6-trimethylbenzyl)phosphine oxide (trade name "Omnirad 819" manufactured by IGM Resins B.V.)

(E): Petroleum resin (trade name "T-REZHA105" manufactured by JXTG Energy Co., Ltd., hydrogenated resin (alicyclic saturated hydrocarbon resin containing dicyclopentadiene as a monomer component), softening point (nominal value) ): 104.5°C, weight average molecular weight (nominal value): 610)

(2) Production of polarizing plate

After corona treatment was applied to the surface of a polymethyl methacrylate (PMMA) film with a thickness of 60 μm , the curable adhesive prepared in (1) was applied to the corona treated surface using an adhesive coating device. Composition C. The obtained coating layer and a polyvinyl alcohol-iodine-based polarizer having a thickness of 23 μm were laminated using a roll to obtain a polarizer with a PMMA film.

Next, after corona treatment was applied to the surface of a retardation film with a thickness of 50 μm (trade name “ZEONOR”, manufactured by Zeon Japan Co., Ltd.] composed of a cyclic polyolefin resin, the corona treated surface was treated with corona. The curable adhesive composition B prepared in accordance with the following description was applied using an adhesive coating apparatus. The obtained coating layer and the polarizer surface of the PMMA film-attached polarizer were laminated using a roll to obtain a laminated body. From the retardation film side of the laminated body, the total cumulative light amount (the cumulative amount of light irradiation intensity in the wavelength region of 320 to 400 nm) is about 200 mJ/cm ² (by measuring device: UV manufactured by Fusion UV Co., Ltd.) The measured value of Power PuckII) ultraviolet (UVB), by this, the layer of curable adhesive composition B and the layer of curable adhesive composition C are hardened, and the polarizing plate was produced. The thickness of the hardened layer of the curable adhesive composition C was about 10 μm , and the thickness of the hardened layer of the curable adhesive composition B was about 2.5 μm .

The curable adhesive composition B was prepared as follows: 3',4'-epoxycyclohexylmethyl ester (trade name made by Daicel Co., Ltd.) with respect to 3,4-epoxycyclohexanecarboxylic acid "Celloxide 2021P") 100 parts by mass, 25 parts by mass of 1,4-butanediol diglycidyl ether (trade name "EX-214L" manufactured by Nagase Chemtex Co., Ltd.) and a photopolymerization initiator (Sun Apro Co., Ltd.) were added Co., Ltd. product name "CPI-100P") 5.6 parts by mass and mixed.

<Examples 11 to 12 and Comparative Examples 2 to 3>

A curable adhesive composition C was prepared in the same manner as in Example 10, except that the compounding amounts of the compounding components were changed to those shown in Table 2. Further, a polarizing plate was produced in the same manner as in Example 10 except that this curable adhesive composition C was used.

<Measurement and Evaluation>

(1) Moisture permeability of cured film formed from curable adhesive composition C

Curable adhesive composition C was applied to a PMMA film having a thickness of 60 μm after corona treatment was applied using an adhesive coating apparatus.

On the coating layer of the curable adhesive composition C, an untreated polyethylene terephthalate (PET) film was laminated and bonded using a roll. Next, the total cumulative light amount of irradiation (the cumulative amount of light irradiation intensity in the wavelength region of 320 to 400 nm) is about 200 mJ/cm ² (measured value by measuring device: UV Power Puck II manufactured by Fusion UV Co., Ltd.) Ultraviolet rays (UVB) were used to harden the adhesive layer to obtain a laminate having a layer configuration of PMMA film/hardened adhesive layer/PET film. Then, the PET film was peeled off to obtain a laminate (sample for moisture permeability measurement) having a layer structure of a PMMA film/cured adhesive layer (cured film).

For the obtained laminate (sample for moisture permeability measurement), the moisture permeability [g/(m ² .24hr) at a temperature of 40°C and a relative humidity of 90% was measured by the moisture permeability cup method specified in JIS Z 0208. ]. Incidentally, at the time of the measurement, the cured adhesive layer (cured film) in the above-mentioned laminate was placed in an environment of a temperature of 40° C. and a relative humidity of 90%. Moreover, the laminated system is attached to the moisture-permeable cup so that the cured film may face the outside.

The results are shown in the column of "moisture permeability of the laminate" in Table 2. The numerical system in parentheses shows the thickness (unit: μm ) of the cured film which the laminated body has.

Moreover, using the water vapor transmission rate (Jt) of the obtained laminated body, the water vapor transmission rate (J) in temperature 40 degreeC and relative humidity 90% of the cured film itself was calculated|required by the following formula.

1/Jt=(1/J)+(1/Jsub)

The PMMA film with a thickness of 60 μm as the base film, the moisture permeability (Jsub) measured by the moisture permeable cup method specified in JIS Z 0208 under the conditions of a temperature of 40° C. and a relative humidity of 90% is 70 g/(m ^2.24hr ).

The results are shown in the column of "Moisture permeability of cured film" in Table 2. The numerical system in parentheses represents the thickness (unit: μm ) of the cured film.

(2) Evaluation of the adhesion between the polarizer and the PMMA film in the polarizer (initial stage)

An adhesive layer was formed on the PMMA film side of the obtained polarizing plate. The polarizing plate with the obtained adhesive layer was cut into a size of 200 mm in length (parallel to the absorption axis direction of the polarizer)×25 mm in width, and the adhesive layer was bonded to a glass plate to obtain a laminate. The obtained laminate was used as a test piece for measuring the peel strength between the polarizer and the PMMA film. Insert the cutting edge of the cutter into the polarized light of the test piece Between the sheet and the PMMA film, 30 mm was peeled off from the end in the longitudinal direction, and the peeled portion was picked up by the gripping portion of the tester, and the glass plate was sandwiched by the gripping portion. For the test piece in this state, in an environment with a temperature of 23°C and a relative humidity of 55%, according to JIS K 6854-2: 1999 "Adhesives - Test Method for Peeling Adhesive Strength - Part 2: Peeling at 180°", with a clip The peeling test was performed at a moving speed of 300 mm/min, and the average peeling force over the length of 30 mm excluding the nip portion covering 170 mm was obtained as the peeling strength between the polarizer and the PMMA film. The results are shown in Table 2. The peeling strength was measured after making a polarizing plate and leaving it to stand in an environment with a temperature of 23° C. and a relative humidity of 50% RH for 24 hours.

In Table 2, the so-called "broken" means that the peeling strength is extremely high, and the PMMA film or the polarizer is broken before the film is peeled off.

(3) Evaluation of the adhesion between the polarizer in the polarizer and the PMMA film (after exposure to a high temperature and high humidity environment)

An adhesive layer was formed on the PMMA film side of the obtained polarizing plate. The obtained polarizing plate with the adhesive layer was cut into a size of 200 mm in length (parallel to the absorption axis direction of the polarizer)×25 mm in width, and the adhesive layer was bonded to glass to obtain a laminate. The obtained laminate was left to stand for 24 hours in a high temperature and high humidity environment with a temperature of 80°C and a relative humidity of 90% RH, and then was left in an environment with a temperature of 23°C and a relative humidity of 50% RH for 24 hours. Then, the blade of the cutter was inserted between the polarizer and the PMMA film of the obtained laminate, and 30 mm was peeled from the end in the longitudinal direction. Attached to the glass plate. For the test piece in this state, in an environment with a temperature of 23°C and a relative humidity of 55%, according to JIS K 6854-2: 1999 "Adhesives - Test Method for Peeling Adhesive Strength - Part 2: Peeling at 180°", with a clip The peeling test was performed at a moving speed of 300 mm/min, and the average peeling force over the length of 30 mm excluding the nip portion covering 170 mm was obtained as the peeling strength between the polarizer and the PMMA film. The results are shown in Table 2.

[Table 2]

10: First thermoplastic resin film

15: The first adhesive layer

30: polarizer

Claims (12)

A curable adhesive composition comprising: a maleic anhydride modified compound (A), an unmodified polybutene (B), a (meth)acrylate compound (C), and a photopolymerization initiator (D). The curable adhesive composition according to claim 1, wherein in 100 mass % of the total amount of the maleic anhydride-modified compound (A) and the unmodified polybutene (B), the cis-butylene is The content of the olefinic anhydride-modified compound (A) is 40% by mass or more and 90% by mass or less. The curable adhesive composition according to claim 1 or 2, wherein the (meth)acrylate compound (C) contains a monofunctional (meth)acrylate compound (C-1). The curable adhesive composition according to claim 3, wherein the content of the monofunctional (meth)acrylate compound (C-1) in 100% by mass of the (meth)acrylate compound (C) It is 60 mass % or more and 99 mass % or less. The curable adhesive composition according to claim 3 or 4, wherein the monofunctional (meth)acrylate compound (C-1) contains an alicyclic (meth)acrylate compound and an aromatic compound selected from the group consisting of at least one compound of the group consisting of (meth)acrylate compounds. The curable adhesive composition according to any one of claims 3 to 5, wherein the monofunctional (meth)acrylate compound (C-1) contains an alicyclic (meth)acrylate compound And (meth)acrylic acid straight or branched chain C ₄ -C ₃₆ alkyl ester compounds. The curable adhesive composition according to claim 6, wherein the (meth)acrylic acid alicyclic alkyl ester compound and the (meth)acrylic acid linear or branched chain C ₄ -C ₃₆ alkyl ester compound Content of the said (meth)acrylic-acid alicyclic alkyl ester compound is 30 mass % or more and 80 mass % or less in the total amount of 100 mass %. The curable adhesive composition according to any one of claims 1 to 7, further comprising a petroleum resin (E). The curable adhesive composition according to any one of claims 1 to 8, wherein the maleic anhydride-modified compound (A) contains a maleic anhydride-modified polymer (A-1) . The curable adhesive composition according to any one of claims 1 to 9, wherein the cured film with a thickness of 10 μm composed of the curable adhesive composition has 400 g at a temperature of 40° C. and a relative humidity of 90% /(m ² .24hr) or less moisture permeability. A polarizing plate comprising a polarizer, an adhesive layer and a thermoplastic resin film in sequence, wherein the adhesive layer is a cured product layer of the curable adhesive composition according to any one of claims 1 to 10. The polarizing plate according to claim 11, wherein the thermoplastic resin film is a (meth)acrylic resin film.

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