TW202239894A - 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 polarizing sheet to a thermoplastic resin film, and a polarizer including sequentially a polarizing sheet, an adhesive layer and a thermoplastic resin film, wherein the polarizing sheet has good adhesiveness to the thermoplastic resin film. A solution to the aforesaid problem is to provide a curable adhesive composition containing a maleic anhydride-modified compound (A), a (meth) acrylate compound (B), and a photopolymerization initiator (C), wherein the (meth) acrylate compound (B) includes a monofunctional (meth) acrylate compound (B-1) that includes an alicyclic alkyl (meth) acrylate compound and a linear or branched C4-C36 alkyl (meth) acrylate compound, and to provide a polarizer including sequentially a polarizing sheet, an adhesive layer, and a thermoplastic resin film, wherein the adhesive layer is a cured product layer of the aforesaid 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 are widely used in image display devices such as liquid crystal display devices and organic EL display devices, and generally have a structure in which a thermoplastic resin film such as a protective film is bonded to one or both sides of the polarizing plate. Adhesives are usually used in the lamination of polarizers and thermoplastic resin films. As such adhesives, active energy ray-curable adhesives and water-based adhesives are known [for example, JP 2009-008860 A (Patent Document 1)].

[Prior Art Literature]

[Patent Document]

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

The 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 polarizing plate which sequentially comprises a polarizer, an adhesive layer and a thermoplastic resin, and has good adhesion between the polarizer and the thermoplastic resin film.

[1] A curable adhesive composition comprising: a maleic anhydride-modified compound (A), a (meth)acrylate compound (B) and a photopolymerization initiator (C), wherein,

The aforementioned (meth)acrylate compound (B) contains a monofunctional (meth)acrylate compound (B-1),

The aforementioned monofunctional (meth)acrylate compound (B-1) contains an alicyclic alkyl (meth)acrylate compound and a linear or branched C ₄ -C ₃₆ alkyl (meth)acrylate compound.

[2] The curable adhesive composition according to [1], wherein, in 100% by mass of the (meth)acrylate compound (B), the monofunctional (meth)acrylate compound (B-1 ) content is not less than 60% by mass and not more than 99% by mass.

[3] The curable adhesive composition according to [1] or [2], wherein the alicyclic alkyl (meth)acrylate compound and the linear or branched (meth)acrylic acid The content of the alicyclic alkyl (meth)acrylate compound is 5% by mass or more and 80% by mass or less in 100% by mass of the total amount of C ₄ -C ₃₆ alkyl ester compounds.

[4] The curable adhesive composition according to any one of [1] to [3], further comprising unmodified polybutadiene (D).

[5] The curable adhesive composition according to [4], wherein the total amount of the maleic anhydride-modified compound (A) and the unmodified polybutadiene (B) is 100% by mass. , The content of the above-mentioned maleic anhydride modified compound (A) is not less than 40% by mass and not more than 90% by mass.

[6] The curable adhesive composition according to any one of [1] to [5], further comprising a petroleum resin (E).

[7] The curable adhesive composition according to any one of [1] to [6], wherein the maleic anhydride-modified compound (A) contains a maleic anhydride-modified polymer ( A-1).

[8] The curable adhesive composition according to any one of [1] to [7], wherein the 10 μm-thick cured film composed of the curable adhesive composition is heated at a temperature of 40° C. and a relative humidity. At 90%, it has a moisture permeability of 400g/(m ² .24hr) or less.

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

The adhesive layer is a cured layer of the curable adhesive composition described in any one of [1] to [8].

[10] The polarizing plate according to [9], wherein the thermoplastic resin film is a (meth)acrylic resin film.

The present invention can provide a curable adhesive composition suitable for laminating polarizers and thermoplastic resin films, which sequentially includes polarizers, adhesive layers, and thermoplastic resin films, and has good adhesion between polarizers and thermoplastic resin films The polarizer.

10: The first thermoplastic resin film

15: The first adhesive layer

20: Second thermoplastic resin film

25: The second adhesive layer

30: Polarizer

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

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

<Curing Adhesive Composition>

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

In this specification, the so-called polarizing plate means a laminated optical film including a polarizing plate and a thermoplastic resin film laminated on one or both surfaces thereof. In the polarizing plate, the polarizer 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 layer of the adhesive composition.

The polarizing plate may also include a film or layer other than the polarizer and the aforementioned thermoplastic resin film.

The above adhesive composition is a curable adhesive composition containing a maleic anhydride modified compound (A), a (meth)acrylate compound (B) and a photopolymerization initiator (C). The adhesive composition may contain components other than these.

In this specification, the compounds which are exemplified as each component contained or may be contained in the adhesive agent composition can be used alone or in combination of plural types 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 type of maleic anhydride-modified compound (A) or two or more types of maleic anhydride-modified compound (A).

As the maleic anhydride-modified compound (A), a maleic anhydride-modified polymer (A-1) is exemplified.

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 polymers (A-1).

The above maleic anhydride structure means the following structure.

*表示於主鏈之鍵結鍵。

* Indicates a bond in the main chain.

Among the maleic anhydride-modified polymers (A-1), examples of maleic anhydride-modified polymers include diene-based polymers, polyolefin-based polymers, (meth)acrylic-based polymers Polymers, polyester polymers, polystyrene polymers, polyether polymers, etc. These polymers may be homopolymers composed of one type of monomer or copolymers composed of two or more types 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)acryl" and "(meth)acrylate".

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

Polybutadiene may be 1,4-polybutadiene or 1,2-polybutadiene, and may also contain constituent units formed by 1,4-addition and units formed by 1,2-addition Both of the constituent units formed. The 1,4-addition can be trans-addition or cis-addition.

It is preferable that the maleic anhydride-modified polymer (A-1) is a liquid form from a point which can prepare the adhesive agent composition which is a solvent-free type and has favorable adhesive ability. The term "liquid" means that fluidity is exhibited at a temperature of 25°C.

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

The number average molecular weight of the maleic anhydride-modified polymer (A-1) is usually 500 to 15,000, preferably 600 to 12,000, and most preferably 700 to 10,000 from the viewpoint of viscosity and coatability. It is less than or equal to 2,000 to 10,000 more preferably.

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 generally 10KOHmg/g to 200KOHmg/g. From the viewpoint of the adhesive ability of the adhesive composition to the thermoplastic resin film (or layer), etc., Preferably it is not less than 15KOHmg/g and not more than 150KOHmg/g, more preferably not less than 20KOHmg/g and not more than 100KOHmg/g, more preferably not less than 45KOHmg/g and not more than 80KOHmg/g. The use of maleic anhydride-modified polymer (A-1) with an acid value in this range is beneficial to improve the adhesion of the adhesive composition to the thermoplastic resin film (or layer), especially when using polyvinyl alcohol-based When the polarizer is used as a polarizer, it is advantageous to provide an adhesive composition having high adhesiveness 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 a neutralization titration method using phenolphthalein as an indicator according to 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 relative to the thermoplastic resin film ( or layer) from the point of view of adhesive ability, especially in the case of using a polyvinyl alcohol-based polarizer as a polarizer, from the viewpoint of improving the adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film, it is preferable It is not less than 5% by mass and not more than 35% by mass, more preferably not less than 10% by mass and not more than 30% by mass.

[2] (Meth)acrylate compound (B)

The (meth)acrylate compound (B) is a radically polymerizable compound having one or more (meth)acryloxy groups in a molecule.

The adhesive composition may contain 1 type, or 2 or more types of (meth)acrylate compound (B).

Examples of the (meth)acrylate compound (B) include: a monofunctional (meth)acrylate compound (B-1) having one (meth)acryloxy group in the molecule, a monofunctional (meth)acrylate compound (B-1) having two ( Bifunctional (meth)acrylate compound (B-2) of meth)acryloxy group, polyfunctional (meth)acrylate compound having 3 or more (meth)acryloxy groups in the molecule ( B-3).

The (meth)acrylate compound (B) may contain one or more monofunctional (meth)acrylate compounds (B-1), bifunctional (meth)acrylate compounds (B-2) and Multifunctional (meth)acrylate compound (B-3).

An example of the monofunctional (meth)acrylate compound (B-1) is an alkyl (meth)acrylate. Alkyl (meth)acrylates include: methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate Butyl, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, (meth)propylene Decyl (meth)acrylate, Isodecyl (meth)acrylate, Myristyl (meth)acrylate, Undecyl (meth)acrylate, Lauryl (meth)acrylate, Lauryl (meth)acrylate , Cetyl (meth)acrylate, Stearyl (meth)acrylate, Isostearyl (meth)acrylate, Isotetradecyl (meth)acrylate, Behenyl (meth)acrylate Straight chain or branched chain (meth)acrylic acid alkyl ester compounds such as esters.

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

Aralkyl (meth)acrylates such as benzyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, phenoxyethylene glycol (meth)acrylate, (meth)acrylic acid 2-Hydroxy-3-phenoxypropyl ester, ethoxylated o-phenol (meth)acrylate and other (meth)acrylates such as phenoxy esters bonded to ester bonds (-C(=O)-O-) Aromatic (meth)acrylate compounds whose O-group contains an aromatic ring;

Cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, dicyclopentyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, (meth) Alicyclic alkyl (meth)acrylate compounds with an alicyclic ring in the -O- group bonded to an ester bond (-C(=O)-O-), such as isocamphoryl acrylate;

Aminoalkyl (meth)acrylate compounds such as N,N-dimethylaminoethyl (meth)acrylate;

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

Yet another example of the monofunctional (meth)acrylate compound (B-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, neopentylitol mono(meth)acrylate, etc. are bonded to the -O- group of the ester bond (-C(=O)-O-) Hydroxyl-containing (meth)acrylate compounds;

2-carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone (n≒2)mono(meth)acrylate, 1-[2-(meth)acryloxyethyl phthalate base] ester, 1-[2-(meth)acryloxyethyl] hexahydrophthalate, 1-[2-(meth)acryloxyethyl] succinate, 4-[2-(meth)acryloxyethyl] triacid, N-(meth)acryloxy-N', N'-dicarboxymethyl-p-phenylenediamine, etc. are bonded to Ester bond (-C(=O)-O-) The -O- group contains a carboxyl group (meth)acrylate compound, etc.

Examples of the bifunctional (meth)acrylate compound (B-2) include alkanediol di(meth)acrylate, polyoxyalkylene diol di(meth)acrylate, halogen-substituted alkanediol di(meth)acrylate, base) acrylates, di(meth)acrylates of aliphatic polyols, di(meth)acrylates of hydrogenated dicyclopentadiene or tricyclodecanedialkane alcohols, dioxane glycol Or di(meth)acrylate of dioxane dialkyl alcohol, di(meth)acrylate of alkylene oxide adduct of bisphenol A or bisphenol F, bis(meth)acrylate of bisphenol A or bisphenol F base) epoxy acrylate, etc.

When more specific examples of the bifunctional (meth)acrylate compound (B-2) are given, they include: ethylene glycol di(meth)acrylate, 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, neopentylthritol di(meth)acrylate, di(trimethylolpropane)di(meth)acrylate, di 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, polybutylene glycol di(meth)acrylate, silicone di(meth)acrylate, neopentyl glycol hydroxytrimethyl acetate di(meth)acrylate, 2,2-bis[4-(meth)acryloxyethoxyethoxyethoxyphenyl]propane, 2,2-bis[4-(meth)acryl Oxyethoxyethoxycyclohexyl]propane, hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, di(meth)acrylate 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(hydroxyethyl)isocyanurate di(meth)acrylate, bis(meth)acrylate of ethoxylated bisphenol A base) acrylate, propoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate, propoxylated bisphenol F di(meth)acrylate, etc.

The bifunctional (meth)acrylate (B-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 viewpoint of moisture permeability of the cured product, compatibility with the maleic anhydride modified compound (A), and adhesion to thermoplastic resin films (especially (meth)acrylic resin films), The bifunctional (meth)acrylate (B-2) preferably includes a compound represented by the following formula, more preferably a compound represented by the following formula.

In the formula, R ₁ and R ₂ 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 of 1 to 20, and m represents an integer of 1 to 20.

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

Examples of polyfunctional (meth)acrylate compounds (B-3) having three or more (meth)acryloxy groups in the molecule: glycerol tri(meth)acrylate, alkoxylated glycerol tri(meth)acrylate ) acrylate, trimethylolpropane tri(meth)acrylate, di(trimethylolpropane) tri(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, new Pentaerythritol Tri(Meth)acrylate, Neopentylthritol Tetra(Meth)propane Acrylic acid ester, diperythritol tetra(meth)acrylate, diperythritol penta(meth)acrylate, diperythritol hexa(meth)acrylate, etc. trifunctional or more aliphatic multifunctional Poly(meth)acrylates of alcohols;

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)acryloxyethoxyethoxy]propane;

Tris(hydroxyethyl)isocyanuric acid tri(meth)acrylate, etc.

From the viewpoint of reducing the viscosity of the adhesive composition, the viewpoint of the adhesive ability of the adhesive composition to the thermoplastic resin film (or layer), and the viewpoint of the moisture and heat durability of the polarizing plate using the polyvinyl alcohol-based polarizer, that is , the (meth)acrylate compound (B) is preferably Contains a monofunctional (meth)acrylate compound (B-1).

When the total amount of the (meth)acrylate compound (B) is 100% by mass, the content of the monofunctional (meth)acrylate compound (B-1) is usually 60% by mass or more, compared to the adhesive composition From the viewpoint of the adhesiveness of the thermoplastic resin film (or layer) and the moisture-heat durability of a polarizing plate using a polyvinyl alcohol-based polarizer, it is preferably at least 70% by mass, particularly preferably at least 80% by mass.

When the total amount of (meth)acrylate compound (B) is set to 100% by mass, the content of monofunctional (meth)acrylate compound (B-1) can be 100% by mass, but from 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, particularly preferably 98% by mass or less, and may be 90% by mass or less.

When the content of the monofunctional (meth)acrylate compound (B-1) is less than 100% by mass, the remainder of the (meth)acrylate compound (B) is a bifunctional (meth)acrylate compound ( B-2) And/or polyfunctional (meth)acrylate compound (B-3), Preferably it contains bifunctional (meth)acrylate compound (B-2).

From the viewpoint of reducing the viscosity of the adhesive composition, the viewpoint of the adhesive ability of the adhesive composition to the thermoplastic resin film (or layer), and the viewpoint of the moisture-heat durability of the polarizing plate using the polyvinyl alcohol-based polarizer, Monofunctional (meth)acrylate compound (B-1) preferably contains (meth)acrylic acid cycloalkyl ester compound and linear or branched chain (meth)acrylate C ₄ -C ₃₆ alkyl compound , and is composed of aliphatic cycloalkyl (meth)acrylate compound and linear or branched C ₄ -C ₃₆ alkyl (meth)acrylate compound.

Straight chain or branched chain (meth)acrylic acid C ₄ -C ₃₆ alkyl ester compounds include, for example: butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate ester, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, (meth)acrylate ) lauryl acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, isotetradecyl (meth)acrylate, (meth)acrylic acid Behenyl ester, myristyl (meth)acrylate, etc.

From the viewpoint of the moisture-heat durability of a polarizing plate using a polyvinyl alcohol-based polarizer, the linear or branched (meth)acrylate C ₄ -C ₃₆ alkyl compound preferably has 8 or more carbon atoms, especially The best is 10 or more, and the most preferred is 12 or more. This carbon number may be 24 or less, and may be 22 or less.

From the viewpoint of the adhesive ability of the adhesive composition and the moisture-heat durability of the polarizing plate using the polyvinyl alcohol-based polarizer, the alicyclic alkyl (meth)acrylate compound and the linear or branched chain In 100% by mass of the total amount of C ₄ -C ₃₆ alkyl (meth)acrylate compounds, the content of alicyclic alkyl (meth)acrylate compounds is preferably 5% by mass or more and 80% by mass or less, particularly preferably 10% by mass. The mass % is more than 70 mass %, more preferably 15 mass % or more and 60 mass % or less, especially preferably 20 mass % or more and 50 mass % or less.

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

[3] Photopolymerization initiator (C)

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

The adhesive composition may contain only 1 type, or may contain 2 or more types of photoinitiators (C).

The photopolymerization initiator (C) is not particularly limited, and examples thereof include oxime compounds such as O-acyl oxime compounds, alkylphenone compounds, and acyl phosphine oxide compounds.

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

Examples of O-acyl oxime compounds include: N-benzoyloxy-1-(4-phenylmercaptophenyl)butane-1-one-2-imine, N-benzoyloxy-1 -(4-phenylmercaptophenyl)octan-1-one-2-imine, N-benzoyloxy-1-(4-phenylmercaptophenyl)-3-cyclopentyl Propan-1-one-2-imine, N-acetyloxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethyl Alkane-1-imine, N-acetyloxy-1-[9-ethyl-6-{2-methyl-4-(3,3-dimethyl-2,4-dioxanyl Methyloxy)benzoyl}-9H-carbazol-3-yl]ethane-1-imine, N- Acetyloxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-3-cyclopentylpropane-1-imine, N- Benzoyloxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-3-cyclopentylpropane-1-one-2- Imine, N-acetyloxy-1-[4-(2-hydroxyethyloxy)phenylhydrogensulfurylphenyl]propan-1-one-2-imine, N-acetyloxy Base-1-[4-(1-methyl-2-methoxyethoxy)-2-methylphenyl]-1-(9-ethyl-6-nitro-9H-carbazole-3 -yl) methane-1-imine and the like.

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.

Compounds having a structure represented by formula (d4) include: 2-methyl-2-morpholinyl-1-(4-methylsulfanylphenyl)propane-1-one, 2-dimethyl Amino-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.

Compounds having a structure represented by formula (d5) include: 2-hydroxyl-2-methyl-1-phenylpropane-1-one, 2-hydroxyl-2-methyl-1-[4-(2 -Hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexyl Phenyl ketone, oligomers of 2-hydroxy-2-methyl-1-(4-isopropenylphenyl)propan-1-one, α,α-diethoxyacetophenone, benzyl di Methyl ketal, etc.

Commercial items 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-trimethylbenzoyl)phosphine oxide (for example, trade name "Omnirad 819" (manufactured by IGM Resins B.V.)), 2,4,6 -Trimethylbenzoyldiphenylphosphine oxide and the like.

Further examples of the photopolymerization initiator (C) include:

Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and other benzoin compounds;

Benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3', 4,4'-tetrakis(tert-butylperoxycarbonyl)diphenylketone, 2,4,6-trimethyldiphenylketone, 4,4'-bis(N,N'-dimethylamine Base)-diphenyl ketone compounds such as diphenyl ketone;

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

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 compounds, and the like.

When the total amount of the adhesive composition is 100% by mass, the content of the photopolymerization initiator (C) 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 adhesive From the viewpoint of adhesive ability of the adhesive composition to the thermoplastic resin film (or layer), it is preferably from 0.5% by mass to 15% by mass, particularly preferably from 1% by mass to 10% by mass (for example, 8% by mass or less ).

When the total amount of the (meth)acrylate compound (B) is 100 parts by mass, the content of the photopolymerization initiator (C) is usually not less than 0.1 parts by mass and not more than 30 parts by mass. From the viewpoint of adhesive composition and the adhesive ability of the thermoplastic resin film (or layer), it is preferably from 0.5 to 20 parts by mass, more preferably from 1 to 10 parts by mass.

[4] Unmodified polybutadiene (D)

The adhesive composition may further contain unmodified polybutadiene (D). It is advantageous that the adhesive composition further contains unmodified polybutadiene (D) from the viewpoint of the adhesive ability of the adhesive composition and the moisture-heat durability of the polarizing plate using the polyvinyl alcohol-based polarizer.

Unmodified polybutadiene (D) is unmodified polybutadiene, and is a polymer obtained by addition polymerization of 1,3-butadiene. The so-called unmodified means that there is no reactive group or polar group in the side chain. The adhesive composition may contain one type of unmodified polybutadiene or two or more types of unmodified polybutadiene.

Unmodified polybutadiene (D) may be 1,4-polybutadiene or 1,2-polybutadiene, and may also contain constituent units formed by 1,4-addition (1,4 -addition unit) and the constituent unit formed by 1,2-addition (1,2-addition unit). The 1,4-addition can be trans-addition or cis-addition.

In the case where the unmodified polybutadiene (D) contains both 1,4-addition units and 1,2-addition units, the content of these is usually 1,4-addition in terms of molar ratio Unit/1,2-addition unit=50 to 95/50 to 5, preferably 70 to 90/30 to 10, especially preferably 75 to 90/25 to 10.

The proportion of vinyl groups contained in the unmodified polybutadiene (D) is preferably at most 35%, more preferably at most 30%, preferably at least 1%, and most preferably at least 10%.

It is preferable that unmodified polybutadiene (D) is a liquid form from a point which can prepare the adhesive agent composition which is a solvent-free type and has good adhesive ability. The term "liquid" means that fluidity is exhibited at a temperature of 25°C.

From the point of view of obtaining an adhesive composition with good applicability, the viscosity of the liquid unmodified polybutadiene (D) at 25°C is preferably 0.1Pa. above 100Pa. Below sec, preferably 0.2Pa. sec above 50Pa. sec or less, more preferably 0.5Pa. sec above 10Pa. less than sec.

The number average molecular weight of the unmodified polybutadiene (D) is generally 500 to 15,000, preferably 600 to 10,000, more preferably 700 to 9,000, and more preferably from the viewpoint of viscosity and coatability It is between 1000 and 5000.

The number average molecular weight of the unmodified polybutadiene (D) can be measured as a value in terms of standard polystyrene by gel permeation chromatography (GPC).

When the adhesive composition contains unmodified polybutadiene (D), the content of the unmodified polybutadiene (D) is usually 1 Mass % to 20 mass %, from the point of view of the adhesive ability of the adhesive composition to the thermoplastic resin film (or layer), especially when using a polyvinyl alcohol-based polarizer as a polarizer, from the perspective of improving the polyvinyl alcohol-based polarizer From the viewpoint of the adhesiveness between the polarizer and the thermoplastic resin film, it is preferably at least 2% by mass and not more than 18% by mass, particularly preferably at least 3% by mass and not more than 15% by mass.

When the adhesive composition contains unmodified polybutadiene (D), when the total amount of the adhesive composition is 100% by mass, the maleic anhydride-modified compound (A) and the unmodified polybutadiene The total amount of polybutadiene (D) is usually not less than 4% by mass and not more than 60% by mass. From the viewpoint of the adhesive ability of the adhesive composition to the thermoplastic resin film (or layer), especially when using a polyvinyl alcohol-based polarizer In the case of a polarizer, it is preferable from the viewpoint of improving the adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film. It is not less than 5% by mass and not more than 50% by mass, more preferably not less than 10% by mass and not more than 40% by mass, more preferably not less than 15% by mass and not more than 30% by mass.

When the adhesive composition contains unmodified polybutadiene (D), the maleic anhydride modified compound (A) and the unmodified polybutadiene (D) in the adhesive composition When the total amount is set to 100% by mass, the content of unmodified polybutadiene (D) is usually 5% by mass or more and 65% by mass or less. From the adhesive composition to the thermoplastic resin film (or layer) From the point of view, especially when a polyvinyl alcohol-based polarizer is used as the polarizer, from the viewpoint of improving the adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film, it is preferably 10% by mass or more to 60% by mass % or less, preferably more than 20% by mass and less than 50% by mass.

When the adhesive composition contains unmodified polybutadiene (D), the maleic anhydride modified compound (A) and the unmodified polybutadiene (D) in the adhesive composition When the total amount is set to 100% by mass, the content of the maleic anhydride modified compound (A) is particularly low when using a polyvinyl alcohol-based polarizer from the viewpoint of the adhesive ability of the adhesive composition to the thermoplastic resin film (or layer). When the sheet is used as a polarizer, from the viewpoint of improving the adhesion between the polyvinyl alcohol-based polarizer and the thermoplastic resin film, it is preferably 40% by mass or more and 90% by mass or less, particularly preferably 50% by mass or more. 80% by mass or less.

[5] Tackifier

The adhesive composition may further contain a tackifier. The tackifying resin is not particularly limited, and generally known ones can be appropriately selected, for example: rosin derivatives (such as rosin, polymerized rosin, hydrogenated rosin), terpene (Terpene) resins (such as terpene resin, aromatic modified Terpene resin, terpene phenol resin, hydrogenated terpene resin), petroleum resin, phenol resin, xylene resin, etc.

Among them, the adhesive composition preferably further contains 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 that can form a cured film with low moisture permeability is suitable for applications that require inhibiting the entry and exit of moisture through the cured film. For example, in a polarizing plate in which a thermoplastic resin film is laminated on at least one side of the polarizing plate through an adhesive, or an image display panel including the same, when the adhesive layer has low moisture permeability, it can prevent the polarizing plate from being damaged due to the ingress and egress of moisture. Or the image shows that the panel is curled (warped).

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

Examples of the petroleum resin (E) include aromatic petroleum resins, aliphatic petroleum resins, cycloaliphatic petroleum resins, aliphatic-aromatic petroleum resins, and dihydrobenzopyran (Chroman) resins. Moreover, those which hydrogenated these resins etc. are also mentioned.

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

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

The C9-based petroleum resin may be a resin obtained by copolymerizing a C9 fraction with other monomer components, or may be obtained by hydrogenating or modifying the resin. Other monomer components include C5 fractions.

C9 fractions include, for example, petroleum fractions having about 8 to 10 carbon atoms such as styrene, alkylstyrene, vinyltoluene, 1-methyl-1-phenylethylene, indene, and methylindene.

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

In addition, the petroleum resin (E) is a C5-based petroleum resin obtained by copolymerizing the above-mentioned C5 fraction, and may be obtained by hydrogenating the C5-based petroleum resin or modifying the resin. Furthermore, it may be an alicyclic hydrocarbon-based resin obtained by subjecting the C5 fraction to cyclodimerization and then polymerizing it. Examples of the alicyclic hydrocarbon-based resin include polymers containing structural units derived from dicyclopentadiene, and the like.

The weight average molecular weight of the petroleum resin (E) is usually 500 to 10,000, from the viewpoint of reducing the moisture permeability of the cured film formed by the adhesive composition and the adhesive ability of the adhesive composition to the thermoplastic resin film (or layer) From this point of view, it is preferably from 500 to 7000, more preferably from 600 to 5000, more preferably from 600 to 3000.

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).

When the adhesive composition contains petroleum resin (E), when the total amount of the adhesive composition is set to 100% by mass, the content of petroleum resin (E) decreases from the cured film formed by the adhesive composition. From the viewpoint of moisture permeability and the adhesive ability 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, from the perspective of improving the polyvinyl alcohol-based polarizer From the viewpoint of the adhesiveness with the thermoplastic resin film, it is preferably from 20% by mass to 70% by mass, particularly preferably from 30% by mass to 65% by mass.

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

The water vapor transmission rate J of the cured film composed of the adhesive composition can be specifically measured by producing a laminate in which the cured film is formed on a substrate film whose water vapor transmission rate is known, and can be measured by the above-mentioned method. The water vapor transmission rate of the laminate is obtained from 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 thing similar to the thermoplastic resin film mentioned later can be used. When measuring the water vapor transmission rate of the laminate according to JIS Z 0208, the laminate system is attached to the moisture permeable cup so that the above-mentioned cured film faces outward.

Regarding the above-mentioned laminate, when a (meth)acrylic resin film with a thickness of 60 μm is used as the above-mentioned base film, the (meth)acrylic resin film and the cured film with a thickness of 10 μm composed of an adhesive composition For laminated films, the moisture permeability 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 preferably below 55g/(m ² .24hr), especially Preferably it is below 50g/(m ² .24hr). The moisture permeability is usually 1 g/(m ² .24 hr) or more, for example, 5 g/(m ² .24 hr) or more.

[6] Other ingredients

The adhesive composition may contain other components than the above.

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 heat stabilizers.

[7] Viscosity of adhesive composition

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

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

<Polarizing plate>

The above-mentioned adhesive composition of the present invention is suitable for bonding thermoplastic resin films, for example, it can be used for bonding thermoplastic resin films and other thermoplastic resin films (or layers). An example of the adhesive composition applicable to the present invention is for a polarizing plate, that is, it can be used to make a polarizing plate. 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 such as a protective film laminated on the polarizer.

The polarizing plate of the present invention includes: a polarizing plate, and a thermoplastic resin film laminated on at least one side of the polarizing plate via an adhesive layer formed of the above-mentioned adhesive composition. The above-mentioned adhesive layer is a cured product layer of the above-mentioned adhesive 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 become good, and in addition, the moisture and heat durability of the polarizing plate can be improved. achieve good. That is, according to the present invention, it is possible to provide a polarizing plate having good adhesion between the polarizing plate and the thermoplastic resin film even after being left in a hot and humid 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

An example of the layer constitution of the polarizing plate of the present invention is shown in FIGS. 1 and 2 .

As shown in Figure 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, it may include: a polarizer 30, and a polarizer on one side of the polarizer 30 The first thermoplastic resin film 10 is laminated and bonded with the first adhesive layer 15 interposed therebetween.

The first adhesive layer 15 is preferably in direct contact with the first thermoplastic resin film 10 .

The polarizer 30 is preferably in direct contact with the first adhesive layer 15 .

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

The first adhesive layer 15 is preferably in direct contact with the first thermoplastic resin film 10 .

The polarizer 30 is preferably in direct contact with the first adhesive layer 15 .

The second adhesive layer 25 is preferably in direct contact with the second thermoplastic resin film 20 .

The polarizer 30 is preferably in direct contact with the second adhesive layer 25 .

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

When two adhesive layers are formed from the adhesive composition of the present invention, these adhesive compositions may have the same composition or different compositions.

Not limited to the examples shown in FIG. 1 and FIG. 2 , the polarizing plate of the present invention may include other layers (or films) other than those mentioned above. Other layers include, for example: an adhesive layer laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20 and/or the polarizer 30; a separation film (also called is a "peeling film"); a protective film laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20 and/or the polarizer 30 (also called "surface protection film"); on the first thermoplastic resin film membrane 10. An optically functional film (or layer) laminated on the outer surface of the second thermoplastic resin film 20 and/or the polarizer 30 via an adhesive layer or an adhesive layer.

[2] Polarizer

The polarizer 30 is a film having a function of selectively passing linearly polarized light in a certain direction from natural light. The polarizer 30 includes, for example: an iodine-based polarizer that absorbs and aligns iodine as a dichroic dye on a polyvinyl alcohol-based resin film; Dye-based polarizers; and coated polarizers coated with dichroic dyes in Lyotropic liquid crystal state, aligned and immobilized, etc. These polarizers are called absorbing polarizers because they selectively transmit linearly polarized light in one direction and absorb linearly polarized light in another direction from natural light.

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 makes the linearly polarized light in another direction A scattering type polarizer that scatters linearly polarized light, but an absorption type polarizer is preferable from the viewpoint of excellent visibility when the polarizer is applied to an image display device or the like.

Among them, the polarizer 30 is particularly preferably a polyvinyl alcohol-based polarizer made of a polyvinyl alcohol-based resin, and more preferably a polyvinyl alcohol-based polarizer made of a polyvinyl alcohol-based resin film that absorbs a dichroic dye such as iodine or a dichroic dye and aligns it to a polyvinyl alcohol-based resin film. The alcohol-based polarizer is particularly preferably a polyvinyl alcohol-based polarizer in which iodine is adsorbed and aligned to 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 be less than 30 μm, preferably less than 25 μm (for example, less than 20 μm, especially less than 15 μm, especially less than 10 μm, especially less than 8 μm). Polarizer The thickness of 30 is usually 2 μm or more. Reducing the thickness of the polarizer 30 is beneficial to the thinning of the polarizer and the image display device to which the polarizer is applied.

[3] Thermoplastic resin film

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 can be respectively films made of a thermoplastic resin with light transmission (preferably optically transparent), such as a chain polyolefin resin (polyolefin resin). Polyolefin-based resins such as vinyl resins, polypropylene-based resins, etc.), cyclic polyolefin-based resins (norbornene-based resins, etc.); cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; polyterephthalate Polyester-based resins such as ethylene formate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate-based resins; (meth)acrylic-based resins; or mixtures and copolymers thereof.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be any of unstretched films and uniaxially or biaxially stretched films, respectively. Biaxial stretching can be synchronous biaxial stretching that stretches in two stretching directions simultaneously, or sequential biaxial stretching that stretches in the first direction and then stretches in a second direction different from this direction stretch.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be a protective film that protects the polarizer 30 , or may be a protective film that also has optical functions such as a retardation film.

For example, by stretching (uniaxially stretching or biaxially stretching, etc.) a film made of the above-mentioned thermoplastic resin or forming a liquid crystal layer on the thermoplastic resin film, it can be configured to impart 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), preferably a copolymer of methacrylate and other copolymerization components.

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

Copolymerization components other than methyl acrylate include, for example, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate or tert-butyl methacrylate, cyclohexyl methacrylate, methyl Methacrylates other than methyl methacrylate such as phenyl acrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate;

Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, or tert-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, etc. Acrylics;

2-(Hydroxymethyl)acrylate, 2-(1-Hydroxyethyl)methylacrylate, 2-(Hydroxymethyl)ethylacrylate, 2-(Hydroxymethyl)acrylate, 2-( Hydroxyalkyl acrylates such as isobutyl hydroxymethyl acrylate or tertiary butyl 2-(hydroxymethyl) acrylate;

Unsaturated acids such as methacrylic acid and acrylic acid;

Chlorostyrene, bromostyrene and other halogenated styrenes;

Vinyltoluene, α-methylstyrene and other substituted styrenes;

Acrylonitrile, methacrylonitrile and other unsaturated nitriles;

Maleic anhydride, citraconic anhydride and other unsaturated anhydrides;

Monofunctional monomers such as unsaturated imides such as phenylmaleimide and cyclohexylmaleimide.

The above-mentioned other monofunctional monomers 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, tetraethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. Base) acrylate, nonaethylene glycol di(meth)acrylate, tetradetraethylene glycol di(meth)acrylate, etc., make the two terminal hydroxyl groups of ethylene glycol or its oligomers by (meth)acrylic acid undergoes esterification;

Esterification of both terminal hydroxyl groups of propylene glycol or its oligomers with (meth)acrylic acid;

Neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, butanediol di(meth)acrylate, etc. Esterify the hydroxyl groups of dihydric alcohols with (meth)acrylic acid By;

Esterification of both terminal hydroxyl groups of bisphenol A, alkylene oxide adducts of bisphenol A, or their halogen-substituted products by (meth)acrylic acid;

Polyols such as trimethylolpropane and neopentylthritol are esterified with (meth)acrylic acid, and epoxy groups of glycidyl (meth)acrylate are ring-opened and added to these terminal hydroxyl groups ;

Diprotic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, and their halogen substitutes, or the ring-opening addition of the epoxy group of glycidyl (meth)acrylate to these Alkylene oxide adducts, etc.;

Aryl (meth)acrylate; aromatic divinyl compounds such as divinylbenzene, etc.

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 a copolymer has. Examples of this reaction include demethanol condensation in the polymer chain between the methyl group of (meth)acrylic acid methyl ester and the hydroxyl group of 2-(hydroxymethyl)methyl acrylate, and the carboxyl group of (meth)acrylic acid and 2-(meth)acrylic acid. - Dehydration condensation reaction of the hydroxyl group of (hydroxymethyl) acrylate in the polymer chain, etc.

The glass transition temperature of the (meth)acrylic resin is preferably from 80°C to 160°C. The glass transition temperature can be determined by the polymerization ratio of methacrylate-based monomers and acrylate-based monomers, each ester group The length of carbon chains and the types of functional groups they have, as well as the adjustment of the polymerization ratio of polyfunctional monomers relative to the monomers as a whole are controlled.

Introducing a ring structure into the main chain of a polymer is also effective as a means for raising the glass transition temperature of a (meth)acrylic resin. 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 anhydride structures such as glutaric anhydride structure and succinic anhydride structure; cyclic imide structures such as glutarimide structure and succinimide structure; lactones such as butyrolactone and valerolactone ring structure.

The more the content of the ring structure in the main chain is increased, the more the glass transition temperature of the (meth)acrylic resin tends to be raised.

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

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 a polymer chain, by heating and optionally in the presence of a catalyst such as an organic phosphorus compound Next, the hydroxyl group and ester group in the obtained polymer are cyclized and condensed to form a lactone ring structure.

The 1st thermoplastic resin film 10 and the 2nd thermoplastic resin film 20 may contain an additive as needed. Examples of additives include slip agents, antiblocking agents, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, impact resistance modifiers, and surfactants.

The (meth)acrylic resin may contain acrylic rubber particles as an impact modifier from the viewpoint of film forming property to a film, impact resistance of a film, and the like. The so-called acrylic rubber particles refer to the particles mainly composed of elastic polymers mainly composed of acrylates, such as: A single-layer structure composed of elastic polymers, or a multi-layer structure in which elastic polymers are used as one layer.

Examples of the above-mentioned elastic polymer include cross-linked elastic copolymers containing alkyl acrylate as a main component and copolymerized with other vinyl monomers and cross-linkable monomers that can be copolymerized with this.

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

Other vinyl monomers that can be copolymerized with the above-mentioned alkyl acrylates include compounds having one polymerizable carbon-carbon double bond in the molecule, more specifically, methacrylates such as methyl methacrylate ; Aromatic vinyl compounds such as styrene; Vinyl cyanide compounds such as acrylonitrile, etc.

The above-mentioned cross-linking monomers include cross-linking compounds having at least two polymerizable carbon-carbon double bonds in the molecule, more specifically, ethylene glycol di(meth)acrylate, butanediol (meth)acrylates of polyhydric alcohols such as di(meth)acrylates; enyl (meth)acrylates such as allyl (meth)acrylates; divinylbenzene, etc.

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

When the thermoplastic resin film is a (meth)acrylic resin film, the adhesive composition of the present invention can especially exhibit good adhesion. Therefore, the adhesive composition of the present invention can be suitably used for laminating a polarizer and a (meth)acrylic resin film.

As for the (meth)acrylic resin film, it is preferable that this resin component consists of (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 may be 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 thickness, the presence or absence of additives, 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 resin film (preferably a cyclic polyolefin resin film), cellulose An ester-based resin or a polyester-based resin film.

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

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may also be equipped with a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antireflection layer, and an antireflection layer on its outer surface (the surface opposite to the polarizer 30). Surface treatment layers (coating layers) such as electrostatic layers, antifouling layers, and conductive layers.

The thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 are generally 5 μm to 200 μm, preferably 10 μm to 120 μm, particularly preferably 10 μm to 85 μm, and more preferably 15 μm to 65 μm. The thicknesses of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may each be 50 μm or less, or may be 40 μm or less. Reducing the thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 contributes to the thinning of polarizing plates and image display devices to which polarizing plates are applied.

From the point of view of improving the adhesion, saponification treatment, plasma treatment, corona treatment, and primer can be performed on the surface of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 coated with the adhesive composition. Treatment and other surface modification treatment.

[4] Production of polarizing plate and adhesive layer

By laminating the first thermoplastic resin film 10 on one side of the polarizer 30 via the first adhesive layer 15, the polarizer having the structure shown in FIG. The second thermoplastic resin film 20 is further laminated via the second adhesive layer 25 to obtain a polarizing plate having the configuration shown in FIG. 2 .

In the case of 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 as "thermoplastic resin films"), these thermoplastic resin films can be staged every Next, only one side of the lamination is carried out, and the lamination and adhesion of the thermoplastic resin film on both sides can also be carried out at the same time.

In the polarizing plate having the structure 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 hardened layer of the adhesive composition of the present invention.

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

In the polarizing plate of the composition shown in FIG. 2, any one of the first adhesive layer 15 and the second adhesive layer 25 may be formed by the adhesive composition of the present invention, and the other may be formed by the adhesive composition of the present invention. Formed by other adhesive compositions different from the adhesive composition.

Other adhesive compositions include conventionally known water-based adhesives and active energy ray-curable adhesives.

Examples of the water-based adhesive include conventionally known adhesive compositions using polyvinyl alcohol-based resins or urethane resins as main components.

The active energy ray-curable adhesive is an adhesive that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. In the case of using an active energy ray-curable adhesive, 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 an epoxy compound curable by cationic polymerization as a curable component, preferably an ultraviolet curable adhesive containing the epoxy compound as a curable component. The term "epoxy compound" means a compound having an average of one or more (preferably two or more) epoxy groups in the molecule. Epoxy-based compounds may be used alone or in combination of two or more.

Examples of epoxy-based compounds include hydrogenated epoxy-based compounds obtained by hydrogenating the aromatic rings of aromatic polyols to obtain alicyclic polyols, and then reacting epichlorohydrin with the alicyclic polyols. (glycidyl ethers of polyhydric alcohols having an alicyclic ring); aliphatic epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts; having one or more bonds in the molecule Alicyclic epoxy compounds, etc. in epoxy compounds of epoxy groups in alicyclic rings.

The active energy ray-curable adhesive may contain a radically polymerizable (meth)acrylic compound as a hardening component instead of the above-mentioned epoxy compound, or contain both an epoxy compound and a radically polymerizable (meth)acrylic compound. ) Acrylic compounds. Examples of (meth)acrylic compounds include: (meth)acrylate monomers having one or more (meth)acryloxy groups in the molecule; obtained by reacting two or more functional group-containing compounds, And a (meth)acryloxy group-containing compound such as a (meth)acrylate oligomer having at least 2 (meth)acryloxy groups in the molecule.

In the case of containing an epoxy compound curable by cationic polymerization as a curable component, it is preferable that the active energy ray-curable adhesive contains a photocationic polymerization initiator. As a photocationic polymerization initiator, an aromatic diazonium salt; Onium salts, such as an aromatic iodonium salt and an aromatic permeicium salt; Iron-arene complex, etc. are mentioned, for example.

When containing a radically polymerizable component such as a (meth)acrylic compound, it is preferable that the active energy ray-curable adhesive agent contains a photoradical polymerization initiator. Examples of photoradical polymerization initiators include: Acetophenone-based initiators, diphenyl ketone-based initiators, benzoin ether-based initiators, thioxanthone-based initiators, xanthone, fluorenone (Fluorenone), camphorquinone, benzaldehyde ( Benzaldehyde), anthraquinone, etc.

The bonding of 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 injecting the adhesive composition into the polarizer Between the sheet 30 and the thermoplastic resin film, both films are laminated via a layer of an adhesive composition, and are bonded by pressing from above and below using a bonding roller, for example.

For the formation of the adhesive composition layer, various coating methods such as a doctor blade, a wire rod, a die coater, a comma wheel coater, and a gravure coater can be used. In addition, the polarizer 30 and the thermoplastic resin film may be continuously supplied so that the bonding surface of both is inside, and the adhesive composition may be poured in between.

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, fixed Anchor coating treatment and other easy-adhesive treatment (surface activation treatment).

In the case of using an active energy ray-curable adhesive, the active energy ray is irradiated to harden the adhesive composition layer.

The light source for irradiating active energy rays may be any 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, for example, 0.1 μm to 100 μm in a polarizing plate, preferably 0.5 μm to 80 μm, especially preferably 1 μm or less 60 μm or less, more preferably 2 μm or more and 50 μm or less. From the viewpoint of thinning the polarizing plate, the thickness of the adhesive layer is preferably 30 μm or less, 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 the polarizer

[5-1] Optical functional film

The polarizing plate may include other optical functional films other than the polarizing plate 30 for providing desired optical functions, and a suitable example thereof is a retardation film.

As mentioned above, the 1st thermoplastic resin film 10 and/or the 2nd thermoplastic resin film 20 also serve as a retardation film, or laminated|stacked a retardation film further besides a 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.

Retardation films include: birefringent films made of stretched films of thermoplastic resins with light transmission; films with discotic or nematic liquid crystals fixed in alignment; substrate films Those on which the above-mentioned liquid crystal layer is formed.

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

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

Examples of other optical functional films (optical components) that can be included in the polarizing plate include light-gathering plates, brightness enhancement films, reflective layers (reflective films), semi-transmissive reflective layers (semi-transmissive reflective films), light diffusion layers ( light diffusing film), etc. These are generally provided when the polarizing plate is disposed 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 bonding the polarizing plate to image display elements such as liquid crystal cells and organic EL elements, or other optical components. The adhesive layer can be laminated on the outer surface of the polarizer 30 in the polarizing plate with the structure shown in FIG. The outer surface of the resin film 20 .

The adhesive used in the adhesive layer can be used: (meth)acrylic resin or siloxane resin, polyester resin, polyurethane resin, polyether resin, etc. as the base polymer By. Among them, a (meth)acrylic adhesive is preferable from the viewpoints of transparency, adhesive force, reliability, weather resistance, heat resistance, reproducibility, and the like.

The thickness of the adhesive layer is determined according to its adhesive strength, etc., and is suitably in the range of 1 μm to 50 μm, preferably 2 μm to 40 μm.

The polarizing plate may include a separation film laminated on the outer surface of the adhesive layer. The separation membrane may be a film made 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 made 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 bonded to the image display element or other optical components, the protective film will be peeled off together with the adhesive layer.

The pellicle is composed of, for example, a base film and an adhesive layer laminated on the base film. With regard to the adhesive layer, the above statements may be cited.

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

[Example]

The following examples are shown to illustrate the present invention more specifically, but the present invention is not limited to these examples. In the examples, % and parts indicating content and dosage are mass 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 Corporation.

<Example 1>

(1) Preparation of curable adhesive composition

The components shown in Table 1 were mixed in the compounding quantities shown in Table 1, and 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 N4-5000-10MA" manufactured by Synthomer Co., Ltd., number average molecular weight: 5500, viscosity at 25°C: 25 to 60Pa ．sec, acid value: 54KOHmg/g)

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

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

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

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

(D): Unmodified liquid polybutadiene (trade name "Lithene ultra PM4" manufactured by Synthomer Co., Ltd., number average molecular weight: 1500, viscosity at 25°C: 0.7 to 0.95 Pa·sec)

(E): Petroleum resin (trade name "T-REZ HA105" 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

Apply corona treatment to the surface of a polymethyl methacrylate (PMMA: Polymethyl Methacrylate) film with a thickness of 60 μm, and apply the curable adhesive composition A prepared in (1) above using an adhesive coating device on the corona treated surface. The obtained coating layer and a polyvinyl alcohol-iodine polarizer having a thickness of 23 μm were laminated using rolls to obtain a PMMA film-attached polarizer.

Next, corona treatment is applied to the surface of a retardation film with a thickness of 50 μm [manufactured by Zeon Japan Co., Ltd., "ZEONOR"] made of a cyclic polyolefin resin, and an adhesive coating device is used. The curable adhesive composition B prepared in the following description is coated on the corona-treated surface. The obtained coating layer and the polarizer surface of the PMMA film-attached polarizer were laminated using rolls to obtain a laminate. From the retardation film side in the laminate, the total cumulative light amount irradiated (cumulative amount of light irradiation intensity in the wavelength range of 320 to 400 nm) was about ²⁰⁰ mJ/cm The measured value obtained by Power PuckII) ultraviolet rays (UVB), thereby curing the layer of curable adhesive composition B and the layer of curable adhesive composition A to produce a polarizing plate. The thickness of the cured layer of the curable adhesive composition A was about 10 μm, and the thickness of the cured layer of the curable adhesive composition B was about 2.5 μm.

Curable adhesive composition B was prepared in the following manner: 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (product of Daicel Co., Ltd. Name "Celloxide 2021P") 100 parts by mass, 1,4-butanediol diglycidyl ether (trade name "EX-214L" manufactured by Nagase Chemtex Co., Ltd.) 25 parts by mass and a photopolymerization initiator (Sun Apro Co., Ltd. product name "CPI-100P") 5.6 parts by mass were mixed.

<Examples 2 to 3, Comparative Example 1>

Curable adhesive composition A was prepared in the same manner as in Example 1, except that the compounded amounts of the compounded components were changed to those shown in Table 1. In addition, 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

Using an adhesive coating device, curable adhesive composition A was applied to a PMMA film having a thickness of 60 μm after corona treatment.

An untreated polyethylene terephthalate (PET: Polyethylene Terephthalate) film was laminated on the coating layer of the curable adhesive composition A, and bonded using a roll. Then irradiate ultraviolet rays with a total cumulative light quantity (the cumulative quantity of light irradiation intensity in the wavelength region of 320 to 400 nm) of about 200 mJ/cm ² (measured value obtained by a measuring device: UV Power PuckII manufactured by Fusion UV Co., Ltd.) (UVB), whereby the adhesive layer is cured to obtain a laminated body consisting of PMMA film/hardened adhesive layer/PET film. Then, the PET film was peeled off to obtain a layered product (sample for moisture permeability measurement) having a PMMA film/cured adhesive layer (cured film).

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 for the obtained laminate (sample for moisture permeability measurement). )]. During the measurement, the hardened adhesive layer (cured film) in the above-mentioned laminate was placed in an environment with a temperature of 40° C. and a relative humidity of 90%. In addition, the laminated system is attached to the moisture-permeable cup so that the cured film faces outward.

The results are shown in the column of "Water vapor transmission rate of laminated body" in Table 1. The numerical values in parentheses represent the thickness (unit: μm) of the cured film that the laminate has.

Moreover, using the moisture permeability (Jt) of the obtained laminated body, the moisture permeability (J) at the temperature of 40 degreeC and the relative humidity of 90% of the cured film itself was calculated|required according to the following formula.

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

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

The result is shown in the column of "the water vapor transmission rate of the cured film" of Table 1. The values in parentheses represent the thickness of the cured film (unit: μm).

(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 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) x 25 mm in width, and the adhesive layer was attached 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 30mm from the end along the length direction, and use the clamping part of the testing machine to clamp the peeled part, and use the clamping The lower part holds the glass plate. For the test piece in this state, it is in an environment with a temperature of 23°C and a relative humidity of 55%, according to JIS K 6854-2: 1999 "Adhesives - Peel Adhesive Strength Test Method - Part 2: 180° Peel" to clamp The moving speed is 300mm/min to carry out the peeling test, The average peeling force over a length of 170 mm of 30 mm excluding the clamping portion was obtained, and this was used as the peeling strength between the polarizer and the PMMA film. The results are shown in Table 1. The peel strength is measured after making the polarizing plate and leaving it 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 "fracture" means that the peeling strength is extremely large, and the PMMA film or polarizer is broken before the film is peeled off. In Comparative Example 1, the adhesiveness between the polarizer and the PMMA film was too weak to measure the peel strength.

(3) Evaluation of the adhesion between the polarizer and the PMMA film in the polarizing plate (after exposure to 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) x 25 mm in width, and the adhesive layer was attached to a glass plate to obtain a laminate. The obtained laminate was left 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 left for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 50% RH. Then insert the blade of the cutter between the polarizer and the PMMA film of the obtained laminate, peel off 30 mm from the end in the longitudinal direction, and clamp the peeled part by the clamping part of the testing machine, And the glass plate is clamped by clamping the lower part. For the test piece in this state, it is in an environment with a temperature of 23°C and a relative humidity of 55%, according to JIS K 6854-2: 1999 "Adhesives - Peel Adhesive Strength Test Method - Part 2: 180° Peel" to clamp The peeling test was carried out at a moving speed of 300 mm/min, and the average peeling force over a length of 170 mm excluding the 30 mm of the clamping portion was obtained as the peeling strength between the polarizer and the PMMA film. The results are shown in Table 1.

[Table 1]

<Example 4>

(1) Preparation of curable adhesive composition

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

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

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

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

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

(B-1c): Lauryl acrylate (trade name "LA" manufactured by Osaka Organic Chemical Industry Co., Ltd.)

(B-1d): Butyl acrylate (manufactured by Fujifilm Wako Pure Chemical Co., Ltd.)

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

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

(D): Unmodified liquid polybutadiene (trade name "Lithene ultra PM4" manufactured by Synthomer Co., Ltd., number average molecular weight: 1500, viscosity at 25°C: 0.7 to 0.95 Pa·sec)

(E): Petroleum resin (trade name "T-REZ HA105" 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

Corona treatment was applied to the surface of a polymethyl methacrylate (PMMA) film with a thickness of 60 μm, and the hardening adhesive composition C prepared in the above (1) was applied to the electrode using an adhesive coating device. Halo processing surface. The obtained coating layer and a polyvinyl alcohol-iodine polarizer having a thickness of 23 μm were laminated using rolls to obtain a PMMA film-attached polarizer.

Next, corona treatment is applied to the surface of a retardation film with a thickness of 50 μm [manufactured by Zeon Japan Co., Ltd., "ZEONOR"] made of a cyclic polyolefin resin, and an adhesive coating device is used. The curable adhesive composition B prepared in the following description is coated on the corona-treated surface. The obtained coating layer and the polarizer surface of the PMMA film-attached polarizer were laminated using rolls to obtain a laminate. From the retardation film side in the laminate, the total cumulative light amount irradiated (cumulative amount of light irradiation intensity in the wavelength range of 320 to 400 nm) was about ²⁰⁰ mJ/cm The measured value obtained by Power PuckII) ultraviolet rays (UVB), thereby curing the layer of curable adhesive composition B and the layer of curable adhesive composition C to produce a polarizing plate. The thickness of the cured layer of the curable adhesive composition C was about 10 μm, and the thickness of the cured layer of the curable adhesive composition B was about 2.5 μm.

Curable adhesive composition B was prepared in the following manner: 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (product of Daicel Co., Ltd. Name "Celloxide 2021P") 100 parts by mass, 1,4-butanediol diglycidyl ether (trade name "EX-214L" manufactured by Nagase Chemtex Co., Ltd.) 25 parts by mass and a photopolymerization initiator (Sun Apro Co., Ltd. product name "CPI-100P") 5.6 parts by mass were mixed.

<Examples 5 to 8>

Curable adhesive composition C was prepared in the same manner as in Example 4 except that the compounding amounts of the compounding components were changed to those shown in Table 2. In addition, a polarizing plate was produced in the same manner as in Example 4 except that this curable adhesive composition C was used.

〈Measurement and Evaluation〉

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

Using an adhesive coating device, curable adhesive composition C was coated on a PMMA film having a thickness of 60 μm after corona treatment.

An untreated polyethylene terephthalate (PET) film was laminated on the coating layer of the curable adhesive composition C, and bonded using a nip roll. Then irradiate ultraviolet rays with a total cumulative light quantity (the cumulative quantity of light irradiation intensity in the wavelength region of 320 to 400 nm) of about 200 mJ/cm ² (measured value obtained by a measuring device: UV Power PuckII manufactured by Fusion UV Co., Ltd.) (UVB), whereby the adhesive layer is cured to obtain a laminated body consisting of PMMA film/hardened adhesive layer/PET film. Then, the PET film was peeled off to obtain a layered product (sample for moisture permeability measurement) having a PMMA film/cured adhesive layer (cured film).

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 for the obtained laminate (sample for moisture permeability measurement). )]. During the measurement, the hardened adhesive layer (cured film) in the above-mentioned laminate was placed in an environment with a temperature of 40° C. and a relative humidity of 90%. In addition, the laminated system is attached to the moisture-permeable cup so that the cured film faces outward.

The results are shown in the column of "Water vapor transmission rate of laminated body" in Table 2. The numerical values in parentheses represent the thickness (unit: μm) of the cured film that the laminate has.

Moreover, using the moisture permeability (Jt) of the obtained laminated body, the moisture permeability (J) at the temperature of 40 degreeC and the relative humidity of 90% of the cured film itself was calculated|required according to the following formula.

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

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

The result is shown in the column of "the water vapor transmission rate of the cured film" of Table 2. The values in parentheses represent the thickness of the cured film (unit: μm).

(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 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) x 25 mm in width, and the adhesive layer was attached 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 into the polarized light of the test piece Between the sheet and the PMMA film, peel 30mm from the end along the length direction, and use the clamping part of the testing machine to clamp the peeled part, and clamp the glass plate with the clamping lower part. For the test piece in this state, it is in an environment with a temperature of 23°C and a relative humidity of 55%, according to JIS K 6854-2: 1999 "Adhesives - Peel Adhesive Strength Test Method - Part 2: 180° Peel" to clamp The peeling test was carried out at a moving speed of 300 mm/min, and the average peeling force over a length of 170 mm excluding the 30 mm of the clamping portion was obtained as the peeling strength between the polarizer and the PMMA film. The results are shown in Table 2. The peel strength is measured after making the polarizing plate and leaving it 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 "fracture" means that the peeling strength is extremely large, and the PMMA film or the polarizer is broken before the film is peeled off.

(3) Evaluation of the adhesion between the polarizer and the PMMA film in the polarizing plate (after exposure to 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) x 25 mm in width, and the adhesive layer was attached to a glass plate to obtain a laminate. The obtained laminate was left 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 left for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 50% RH. Then insert the blade of the cutter between the polarizer and the PMMA film of the obtained laminate, peel off 30 mm from the end in the longitudinal direction, and clamp the peeled part by the clamping part of the testing machine, And the glass plate is clamped by clamping the lower part. For the test piece in this state, it is in an environment with a temperature of 23°C and a relative humidity of 55%, according to JIS K 6854-2: 1999 "Adhesives - Peel Adhesive Strength Test Method - Part 2: 180° Peel" to clamp The peeling test was carried out at a moving speed of 300 mm/min, and the average peeling force over a length of 170 mm excluding the 30 mm of the clamping portion was obtained as the peeling strength between the polarizer and the PMMA film. The results are shown in Table 2.

[Table 2]

10: The first thermoplastic resin film

15: The first adhesive layer

30: Polarizer

Claims (10)

A curable adhesive composition comprising: a maleic anhydride modified compound (A), a (meth)acrylate compound (B) and a photopolymerization initiator (C), wherein, The aforementioned (meth)acrylate compound (B) contains a monofunctional (meth)acrylate compound (B-1), The aforementioned monofunctional (meth)acrylate compound (B-1) contains an alicyclic alkyl (meth)acrylate compound and a linear or branched C ₄ -C ₃₆ alkyl (meth)acrylate compound. The curable adhesive composition according to claim 1, wherein the content of the monofunctional (meth)acrylate compound (B-1) in 100% by mass of the (meth)acrylate compound (B) is It is not less than 60% by mass and not more than 99% by mass. The curable adhesive composition as described in claim 1 or 2, wherein, in the aforementioned aliphatic cycloalkyl ester compound and the aforementioned linear or branched chain (meth)acrylic acid C ₄ -C ₃₆ Content of the said alicyclic alkyl (meth)acrylate compound is 5 mass % or more and 80 mass % or less in 100 mass % of total amounts of alkyl ester compounds. The curable adhesive composition according to any one of claims 1 to 3, further containing unmodified polybutadiene (D). The curable adhesive composition according to Claim 4, wherein the maleic anhydride-modified compound (A) and the unmodified polybutadiene (B) are included in 100% by mass of the total amount of the maleic anhydride-modified compound (A) and the unmodified polybutadiene (B). The content of the butenedioic anhydride modified compound (A) is not less than 40% by mass and not more than 90% by mass. The curable adhesive composition according to any one of claims 1 to 5, further comprising petroleum resin (E). The curable adhesive composition according to any one of claims 1 to 6, 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 7, wherein the cured film with a thickness of 10 μm made of the aforementioned curable adhesive composition has a temperature of 40°C and a relative humidity of 90%. Moisture permeability below 400g/(m ² .24hr). A polarizing plate, which sequentially includes a polarizer, an adhesive layer, and a thermoplastic resin film, wherein, The aforementioned adhesive layer is a hardened layer of the curable adhesive composition according to any one of claims 1 to 8. The polarizing plate according to claim 9, wherein the thermoplastic resin film is a (meth)acrylic resin film.

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