阅读说明：本技术 固化性组合物及偏振板 (Curable composition and polarizing plate ) 是由 安井未央 岩田智 仲西雄亮 阪上智惠 于 2021-05-31 设计创作，主要内容包括：本发明提供一种固化性组合物,其贮藏稳定性优异,并且在作为粘接剂使用时与聚乙烯醇系偏振片的密合性良好。本发明的固化性组合物包含C9系石油树脂(A)和单官能(甲基)丙烯酸酯化合物(B),C9系石油树脂(A)包含溴值不同的2种以上的C9系石油树脂。(The invention provides a curable composition which has excellent storage stability and good adhesion with a polyvinyl alcohol polarizer when used as an adhesive. The curable composition of the present invention comprises a C9-based petroleum resin (a) and a monofunctional (meth) acrylate compound (B), and the C9-based petroleum resin (a) comprises 2 or more C9-based petroleum resins having different bromine numbers.)

1. A curable composition comprising a C9-series petroleum resin (A) and a monofunctional (meth) acrylate compound (B),

the C9-series petroleum resin (A) contains 2 or more C9-series petroleum resins having different bromine numbers.

2. The curable composition according to claim 1,

the C9 series petroleum resin (A) comprises a C9 series petroleum resin with bromine number less than 0.7g/100g and a C9 series petroleum resin with bromine number more than 0.7g/100 g.

3. A laminate comprising a cured film having a thickness of 10 μm and a (meth) acrylic resin film having a thickness of 60 μm, said curable composition according to claim 1 or 2,

the laminateThe body has a mass of 55 g/(m) at a temperature of 40 ℃ and a relative humidity of 90%²24hr) or less.

4. A polarizing plate comprising a polarizing plate, an adhesive layer and a thermoplastic resin film in this order, wherein the adhesive layer is a cured product layer of the curable composition according to claim 1 or 2.

5. The polarizing plate of claim 4,

the thermoplastic resin film is a (meth) acrylic resin film.

6. The polarizing plate of claim 4 or 5,

the adhesive layer has a thickness of 2 to 50 [ mu ] m.

7. A curable composition comprising a curable monomer and a curable monomer,

comprising a C9 series petroleum resin (A') and a monofunctional (meth) acrylate compound (B),

the iodine value of the C9-based petroleum resin (A') is 2.5g/100g or more and 8g/100g or less.

Technical Field

The present invention relates to a curable composition, and further relates to a polarizing plate comprising a cured product layer thereof.

Background

Polarizing plates widely used in image display devices such as liquid crystal display devices and organic EL display devices generally have a structure in which a thermoplastic resin film such as a protective film is bonded to one surface or both surfaces of a polarizing plate. An adhesive is generally used for bonding the polarizing plate and the thermoplastic resin film. As such an adhesive, an active energy ray-curable adhesive and an aqueous adhesive are known (patent document 1: Japanese patent laid-open No. 2009-008860).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2009-008860

Disclosure of Invention

Problems to be solved by the invention

The present invention aims to provide a curable composition having good storage stability and good adhesion to a polyvinyl alcohol polarizing plate when the curable composition is used as an adhesive.

Means for solving the problems

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

[1] A curable composition comprising a C9-series petroleum resin (A) and a monofunctional (meth) acrylate compound (B), wherein the C9-series petroleum resin (A) comprises 2 or more C9-series petroleum resins having different bromine numbers.

[2] The curable composition according to [1], wherein the C9-based petroleum resin (A) comprises a C9-based petroleum resin having a bromine number of less than 0.7g/100g and a C9-based petroleum resin having a bromine number of 0.7g/100g or more.

[3]A laminate comprising [1]]Or [2]]The laminate of a cured film having a thickness of 10 μm and a (meth) acrylic resin film having a thickness of 60 μm, which is obtained by curing the curable composition as described in (1)Has a molecular weight of 55 g/(m) under the condition²24hr) or less.

[4] A polarizing plate comprising a polarizing plate, an adhesive layer and a thermoplastic resin film in this order, wherein the adhesive layer is a cured product layer of the curable composition described in [1] or [2 ].

[5] The polarizing plate according to [4], wherein the thermoplastic resin film is a (meth) acrylic resin film.

[6] The polarizing plate according to [4] or [5], wherein the adhesive layer has a thickness of 2 μm or more and 50 μm or less.

[7] A curable composition comprising a C9-series petroleum resin (A') and a monofunctional (meth) acrylate compound (B),

the iodine value of the C9-based petroleum resin (A') is 2.5g/100g or more and 8g/100g or less.

Effects of the invention

The curable composition has good storage stability, and when the curable composition is used as an adhesive, the adhesive property with a polyvinyl alcohol polarizer is good.

Drawings

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

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

Description of the reference numerals

10 st thermoplastic resin film, 15 st adhesive layer, 1 st thermoplastic resin film, 20 nd thermoplastic resin film, 25 nd adhesive layer, 30 polarizing plate.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments below. In all the drawings below, the components are illustrated with their scales adjusted as appropriate for easy understanding of the components, and the scales of the components shown in the drawings do not necessarily coincide with the scales of the actual components.

< curable composition >

The curable composition (hereinafter also referred to as "1 st curable composition") according to the present invention includes a C9-based petroleum resin (a) and a monofunctional (meth) acrylate compound (B), and the C9-based petroleum resin (a) includes 2 or more C9-based petroleum resins having different bromine numbers. The curable composition may contain components other than the C9-based petroleum resin (a) and the monofunctional (meth) acrylate compound (B). Examples of the other components include a polyfunctional (meth) acrylate compound (C), a maleic anhydride-modified compound (D), a photopolymerization initiator (E), a curable component other than the monofunctional (meth) acrylate compound (B) and the polyfunctional (meth) acrylate compound (C), a crosslinking agent, a coupling agent, a tackifier, an antioxidant, an ultraviolet absorber, and a heat stabilizer.

Another curable composition (hereinafter, also referred to as "2 nd curable composition") according to the present invention is characterized by containing a C9-based petroleum resin (a ') and a monofunctional (meth) acrylate compound (B), and by having an iodine value of 2.5g/100g or more and 8g/100g or less in the C9-based petroleum resin (a'). In the present specification, the 1 st curable composition and the 2 nd curable composition are collectively referred to as a curable composition.

In the present specification, the compounds exemplified as the respective components contained or capable of being contained in the curable composition may be used alone or in combination in a plurality of ways unless otherwise specified.

In the present specification, "(meth) acrylate" means at least 1 selected from the group consisting of acrylate and methacrylate. The same applies to "(meth) acryloyl group" and "(meth) acrylic group", etc.

[1] C9 series petroleum resin (A)

The C9-series petroleum resin (A) contains 2 or more kinds of C9-series petroleum resins having different bromine numbers. When the 1 st curable composition contains 2 or more kinds of C9-based petroleum resins having different bromine numbers, the composition tends to exhibit good storage stability, and when the composition is used as an adhesive, the composition tends to have good adhesion to a polyvinyl alcohol-based polarizing plate. The bromine number of the C9-based petroleum resin (A) can be measured in accordance with JIS K2605. The bromine number of the C9-based petroleum resin (a) is an index indicating the hydrogenation rate, and a smaller bromine number indicates a higher hydrogenation rate of the C9-based petroleum resin (a).

The C9-based petroleum resin is obtained by copolymerizing a C9 fraction, and may be a hydrogenated resin or a modified resin. The C9-based petroleum resin (a) may contain components other than the C9 fraction, and may be, for example, a resin obtained by copolymerizing a C5 fraction and a C9 fraction (C5C 9-based petroleum resin). Examples of the C9 fraction include petroleum fractions having about 8 to 10 carbon atoms such as vinyl toluene, alkyl styrene, indene, and methyl indene. Examples of the C5 fraction include petroleum fractions having about 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, and isoprene.

The number of the C9-based petroleum resins having different bromine numbers contained in the C9-based petroleum resin (A) may be, for example, 2 to 5, preferably 2 to 4, more preferably 2 or 3, and still more preferably 2.

When 2 kinds of C9-based petroleum resins having different bromine numbers are contained, the mixing ratio ((a 1): (a2)) of the C9-based petroleum resin (a1) having the larger bromine number and the C9-based petroleum resin (a2) having the smaller bromine number may be, for example, 50 or more and less than 100: more than 0 and 50 or less, preferably 60 or more and 90 or less from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate: 10 or more and 40 or less, more preferably 65 or more and 85 or less: 15 or more and 35 or less.

The combination of 2 kinds of C9-based petroleum resins having different bromine numbers is preferably a combination of a C9-based petroleum resin (A1) having a bromine number of less than 0.5g/100g and a C9-based petroleum resin (A2) having a bromine number of 0.7g/100g or more. More preferably, the combination of a C9-based petroleum resin (A1) having a bromine number of 0.01g/100g or more and less than 0.5g/100g and a C9-based petroleum resin (A2) having a bromine number of 0.7g/100g or more and 10g/100g or less, and still more preferably, the combination of a C9-based petroleum resin (A1) having a bromine number of 0.05g/100g or more and less than 0.3g/100g and a C9-based petroleum resin (A2) having a bromine number of 0.7g/100g or more and 5g/100g or less.

Commercially available products can be used as the C9-based petroleum resin (A), and examples thereof include ARKON M-100 (manufactured by Mikan chemical Co., Ltd., bromine number 0.8g/100g), and ARKON P-100 (manufactured by Mikan chemical Co., Ltd., bromine number 0.1g/100 g).

The weight average molecular weight of the C9-based petroleum resin (a) is usually 500 or more and 10000 or less, and from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate, it is preferably 500 or more and 7000 or less, and more preferably 600 or more and 5000 or less. The weight average molecular weight of the C9-based petroleum resin (a) can be measured as a standard polystyrene conversion value by Gel Permeation Chromatography (GPC).

The content of the C9-based petroleum resin (a) is preferably 20 mass% or more and 70 mass% or less, more preferably 30 mass% or more and 65 mass% or less, from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate, assuming that the total amount of the 1 st curable composition is 100 mass%.

The iodine value of the C9-based petroleum resin (A), which will be described later, may be, for example, 2.5g/100g to 8g/100g, preferably 3g/100g to 7g/100g, and more preferably 3.5g/100g to 6g/100 g.

[2] C9-series petroleum resin (A')

The iodine value of the C9-based petroleum resin (A') is 2.5g/100g to 8g/100g, preferably 3g/100g to 7g/100g, and more preferably 3.5g/100g to 6g/100 g. When the 2 nd curable composition contains the C9-based petroleum resin (a'), there is a tendency that good storage stability is exhibited and adhesion to a polyvinyl alcohol-based polarizing plate when used as an adhesive is good.

The iodine value of the C9-based petroleum resin (a') can be measured by the method described in examples.

The iodine value of the C9-based petroleum resin (a') is controlled by a combination of 2 or more petroleum resins having different iodine values, for example.

The number of the C9-based petroleum resins having different iodine values contained in the C9-based petroleum resin (A') is, for example, 2 to 5, preferably 2 to 4, more preferably 2 or 3, and still more preferably 2.

In the case of containing 2C 9-based petroleum resins having different iodine values, the mixing ratio ((A3): (a4)) of the C9-based petroleum resin (A3) having a larger iodine value and the C9-based petroleum resin (a4) having a smaller iodine value may be, for example, 50 or more and less than 100: more than 0 and 50 or less, preferably 60 or more and 90 or less from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate: 10 or more and 40 or less, more preferably 65 or more and 85 or less: 15 or more and 35 or less.

The combination of 2 kinds of C9-based petroleum resins having different iodine values is preferably a combination of a C9-based petroleum resin (A3) having an iodine value of 0.1g/100g or more and 10g/100g or less and a C9-based petroleum resin (a4) having a bromine value of 0.01g/100g or more and 1g/100g or less.

The above description of the C9-based petroleum resin (A) is applied to the commercially available examples of the C9-based petroleum resin (A'), the weight average molecular weight, and the content of the 2 nd curable composition.

The C9-series petroleum resin (a') may contain 2 or more kinds of C9-series petroleum resins. When the C9-based petroleum resin (a') contains 2 or more kinds of C9-based petroleum resins, the bromine numbers of the C9-based petroleum resins may be different from each other. The combinations and ratios of the C9-based petroleum resins having different bromine numbers are within the ranges exemplified and preferred in the above-mentioned C9-based petroleum resin (a).

[ 3] monofunctional (meth) acrylate Compound (B)

The monofunctional (meth) acrylate compound (B) is a radical polymerizable compound having 1 (meth) acryloyloxy group in the molecule.

The curable composition may contain 1 or 2 or more species of monofunctional (meth) acrylate compound (B).

An example of the monofunctional (meth) acrylate compound (B) is an alkyl (meth) acrylate. Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate.

Examples of the monofunctional (meth) acrylate compound (B) include the following compounds and other compounds:

aromatic (meth) acrylate compounds in which the group bonded to the-O-bond of the ester bond (-C (═ O) -O-) includes an aromatic ring, such as aralkyl (meth) acrylates such as benzyl (meth) acrylate, and phenoxy ethyl (meth) acrylate, phenoxyethyleneglycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and ethoxylated-O-phenylphenol (meth) acrylate;

alicyclic alkyl (meth) acrylate compounds in which the group bonded to the-O-bond of the ester bond (-C (═ O) -O-) such as cyclohexyl (meth) acrylate, cyclohexylmethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 1, 4-cyclohexanedimethanol mono (meth) acrylate, isobornyl (meth) acrylate, and the like, contains an alicyclic ring;

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

(meth) acrylate compounds in which a group bonded to an-O-bond of an ester bond (-C (═ O) -O-) such as dicyclopentadiene oxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate contains an ether bond.

Other examples of the monofunctional (meth) acrylate compound (B) include:

(meth) acrylate compounds in which a group bonded to-O-of an ester bond (-C (═ O) -O-) such as 2-hydroxyethyl (meth) acrylate, 2-or 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono (meth) acrylate and the like contains a hydroxyl group;

and (meth) acrylate compounds in which a group bonded to an-O-bond of an ester bond (-C (═ O) -O-) includes a carboxyl group, such as 2-carboxyethyl (meth) acrylate, ω -carboxy-polycaprolactone (N ≈ 2) mono (meth) acrylate, 1- [2- (meth) acryloyloxyethyl ] phthalate, 1- [2- (meth) acryloyloxyethyl ] hexahydrophthalate, 1- [2- (meth) acryloyloxyethyl ] succinate, 4- [2- (meth) acryloyloxyethyl ] trimellitate, and N- (meth) acryloyloxy-N ', N' -dicarboxymethyl-p-phenylenediamine.

When the curable composition contains the monofunctional (meth) acrylate compound (B), the composition tends to exhibit good storage stability, and the adhesion to a polyvinyl alcohol-based polarizing plate tends to be easily improved. The monofunctional (meth) acrylate compound (B) is preferably at least one compound selected from the group consisting of monofunctional alicyclic alkyl (meth) acrylate compounds and aromatic (meth) acrylate compounds, from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate.

The content of the monofunctional (meth) acrylate compound (B) is usually 9 mass% or more and 75 mass% or less, assuming that the total amount of the curable composition is 100 mass%. From the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate, it is preferably 15% by mass or more and 70% by mass or less, and more preferably 20% by mass or more and 60% by mass or less.

[4] polyfunctional (meth) acrylate Compound (C)

The polyfunctional (meth) acrylate compound (C) is a radically polymerizable compound having 2 or more (meth) acryloyloxy groups in the molecule. The curable composition may contain only 1 kind of the polyfunctional (meth) acrylate compound (C), or may contain 2 or more kinds of the polyfunctional (meth) acrylate compounds (C).

Examples of the polyfunctional (meth) acrylate compound (C) include a 2-functional (meth) acrylate compound (C-1) having 2 (meth) acryloyloxy groups in the molecule and a polyfunctional (meth) acrylate compound (C-2) having 3 or more (meth) acryloyloxy groups in the molecule.

Examples of the 2-functional (meth) acrylate compound (C-1) include alkylene glycol di (meth) acrylate, polyoxy alkylene glycol di (meth) acrylate, halogen-substituted alkylene glycol di (meth) acrylate, di (meth) acrylate of aliphatic polyol, di (meth) acrylate of hydrogenated dicyclopentadiene or tricyclodecanedialkanol, di (meth) acrylate of dioxane glycol or dioxane dialkanol, di (meth) acrylate of alkylene oxide adduct of bisphenol A or bisphenol F, and epoxy di (meth) acrylate of bisphenol A or bisphenol F.

Specific examples of the 2-functional (meth) acrylate compound (C-1) 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, pentaerythritol di (meth) acrylate, ditrimethylolpropane di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and mixtures thereof, Poly 1, 4-butanediol di (meth) acrylate, silicone di (meth) acrylate, di (meth) acrylate of neopentyl glycol hydroxypivalate, 2-bis [4- (meth) acryloyloxyethoxyethoxyphenyl ] propane, 2-bis [4- (meth) acryloyloxyethoxyethoxyethoxyethoxyethoxyethoxycyclohexyl ] propane, hydrogenated dicyclopentadienyl di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1, 3-dioxane-2, 5-diyl di (meth) acrylate [ alternative names: dioxane diol di (meth) acrylate ], an acetal compound of hydroxypivalaldehyde and trimethylolpropane [ chemical name: di (meth) acrylate of 2- (2-hydroxy-1, 1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1, 3-dioxane ], tri (hydroxyethyl) isocyanurate di (meth) acrylate, di (meth) acrylate of ethoxylated bisphenol A, di (meth) acrylate of propoxylated bisphenol A, di (meth) acrylate of ethoxylated bisphenol F, di (meth) acrylate of propoxylated bisphenol F, and the like.

The 2-functional (meth) acrylate (C-1) preferably has at least 1 alicyclic skeleton or at least 1 aromatic ring in the molecule, and more preferably has at least 1 aromatic ring.

The 2-functional (meth) acrylate (C-1) preferably contains a compound represented by the following formula, and more preferably a compound represented by the following formula, from the viewpoint of moisture permeability of the cured product and adhesion to a resin film (particularly a (meth) acrylic resin film).

[ solution 1]

(in the formula, R₁And R₂Each independently represents a hydrogen atom or a methyl group, and X represents an ethyleneoxy group (-C)₂H₄O-), or propyleneoxy group (-C)₃H₆O-), n represents an integer of 1 to 20, and m represents an integer of 1 to 20. )

X is preferably an ethyleneoxy group, and the average of the sum of m and n is preferably 2 to 20, more preferably 3 to 15, and particularly preferably 4 to 13.

Examples of the polyfunctional (meth) acrylate compound (C-2) having 3 or more (meth) acryloyloxy groups in the molecule include poly (meth) acrylates of aliphatic polyols having 3 or more functions such as glycerol tri (meth) acrylate, alkoxylated glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like;

poly (meth) acrylates of 3 or more functional halogen-substituted polyols;

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

tri (meth) acrylate of alkylene oxide adduct of trimethylolpropane;

1, 1, 1-tris [ (meth) acryloyloxyethoxyethoxy ] propane;

tris (hydroxyethyl) isocyanurate tri (meth) acrylate, and the like.

The content of the monofunctional (meth) acrylate compound (B) is usually 60 mass% or more, and from the viewpoint of improving storage stability and adhesion to a polyvinyl alcohol-based polarizing plate, it is preferably 70 mass% or more, and more preferably 80 mass% or more, assuming that the total mass of the monofunctional (meth) acrylate compound (B) and the polyfunctional (meth) acrylate compound (C) is 100 mass%.

When the total mass of the monofunctional (meth) acrylate compound (B) and the polyfunctional (meth) acrylate compound (C) is 100 mass%, the content of the monofunctional (meth) acrylate compound (B) is preferably 99 mass% or less, more preferably 98 mass% or less, and may be 90 mass% or less, from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate.

[5] maleic anhydride-modified Compound (D)

The maleic anhydride-modified compound (D) is a compound containing a maleic anhydride structure in the molecule. The curable composition may contain 1 or more species of the maleic anhydride-modified compound (D) from the viewpoint of improving storage stability and from the viewpoint of improving adhesion to a polyvinyl alcohol-based polarizing plate when used as an adhesive.

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

The maleic anhydride-modified polymer (D-1) is a polymer modified by introducing a maleic anhydride structure as a side chain of a polymer. The curable composition may contain only 1 maleic anhydride-modified polymer (D-1), or may contain 2 or more maleic anhydride-modified polymers (D-1).

The maleic anhydride structure mentioned above refers to the following structure.

[ solution 2]

(. sup. represents a bonding end to the main chain.)

Examples of the maleic anhydride-modified polymer (D-1) include a diene polymer, a polyolefin polymer, a (meth) acrylic polymer, a polyester polymer, a polystyrene polymer, and a polyether polymer. These polymers may be homopolymers formed from 1 kind of monomer, or copolymers formed from 2 or more kinds of monomers.

The maleic anhydride-modified polymer (D-1) is preferably in a liquid form so that a solvent-free curable composition having good adhesion can be prepared. The term "liquid" means that it exhibits fluidity at a temperature of 25 ℃.

The viscosity of the liquid maleic anhydride-modified polymer (D-1) at 25 ℃ is preferably 10Pa · sec or more and 10000Pa · sec or less, more preferably 15Pa · sec or more and 7000Pa · sec or less, from the viewpoint of obtaining a curable composition having good coatability.

Preferable examples of the liquid maleic anhydride-modified polymer (D-1) include maleic anhydride-modified polybutadiene, maleic anhydride-modified polyisoprene, and maleic anhydride-modified polyisobutylene. These polymers may be homopolymers or copolymers, respectively. Comonomers when the polymer is a copolymer are, for example, olefin monomers.

The number average molecular weight of the maleic anhydride-modified polymer (D-1) is usually 500 or more and 15000 or less, and from the viewpoint of viscosity and coatability, it is preferably 600 or more and 12000 or less, and more preferably 700 or more and 10000 or less.

The number average molecular weight of the maleic anhydride-modified polymer (D-1) can be measured as a standard polystyrene equivalent value by Gel Permeation Chromatography (GPC).

The acid value of the maleic anhydride-modified polymer (D-1) is usually 10KOHmg/g or more and 200KOHmg/g or less, and from the viewpoint of the adhesion ability of the curable composition to a thermoplastic resin film (or layer), it is preferably 15KOHmg/g or more and 150KOHmg/g or less, more preferably 20KOHmg/g or more and 100KOHmg/g or less, still more preferably 30KOHmg/g or more and 100KOHmg/g or less, and particularly preferably 45KOHmg/g or more and 100KOHmg/g or less.

The acid value of the maleic anhydride-modified polymer (D-1) was determined according to JIS K0070: 1992, neutralization titration with phenolphthalein as an indicator.

The content of the maleic anhydride-modified compound (D) is usually 3 mass% or more and 40 mass% or less when the total amount of the curable composition is 100 mass%, and is preferably 5 mass% or more and 35 mass% or less, more preferably 10 mass% or more and 30 mass% or less, from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate.

[6] photopolymerization initiator (E)

The photopolymerization initiator (E) is not particularly limited as long as it is a compound that can generate an active radical, an acid, or the like by the action of light and initiate polymerization of the monofunctional (meth) acrylate compound (B). The photopolymerization initiator (E) is preferably a compound capable of initiating polymerization of the polyfunctional (meth) acrylate compound (C).

The curable composition may contain only 1 kind of photopolymerization initiator (E), or may contain 2 or more kinds of photopolymerization initiators (E).

The photopolymerization initiator (E) is not particularly limited, and examples thereof include oxime compounds such as O-acyloxime compounds, alkylphenone compounds, acylphosphine oxide compounds, and the like.

The O-acyloxime compound is a compound having a structure represented by the following formula (d). Hereinafter, the bond end is denoted.

[ solution 3]

Examples of the O-acyloxime compound include N-benzoyloxy-1- (4-phenylsulfanylphenyl) butan-1-one-2-imine, N-benzoyloxy-1- (4-phenylsulfanylphenyl) octan-1-one-2-imine, N-benzoyloxy-1- (4-phenylsulfanylphenyl) -3-cyclopentylpropane-1-one-2-imine, N-acetoxy-1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] ethane-1-imine, and N-acetoxy-1- [ 9-ethyl-6- { 2-methyl-4- (3, 3-dimethyl-2, 4-dioxocyclopentylmethoxy) benzoyl } -9H-carbazol-3-yl ] ethane-1-imine, N-acetoxy-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-acetoxy-1- [4- (2-hydroxyethoxy) phenylsulfanylphenyl ] propane-1-one- 2-imine, N-acetoxy-1- [4- (1-methyl-2-methoxyethoxy) -2-methylphenyl ] -1- (9-ethyl-6-nitro-9H-carbazol-3-yl) methane-1-imine, and the like.

Commercially available products such as Irgacure (trade name) OXE01, Irgacure OXE02, Irgacure OXE03 (manufactured by BASF Co., Ltd.), N-1919, NCI-930, and NCI-831 (manufactured by ADEKA Co., Ltd.) can also be used.

The alkylphenone compound has a partial structure represented by the following formula (d4) or a partial structure represented by the following formula (d 5). In these partial structures, the benzene ring may have a substituent.

[ solution 4]

Examples of the compound having the structure represented by the formula (d4) include 2-methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one, 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutan-1-one, and 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] butan-1-one.

Commercially available products such as Omnirad (trade name) 369, Omnirad 907, and Omnirad 379 (manufactured by IGM Resins B.V. Co., Ltd.) may also be used.

Examples of the compound having the structure represented by formula (d5) include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-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 -diethoxy acetophenone, benzildimethyl ketal, and the like.

Commercially available products such as Omnirad (trade name) 184(IGM Resins b.v. corporation) can also be used.

Examples of the acylphosphine oxide compound include phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide (for example, "Omnirad 819" (manufactured by IGM Resins b.v.)), 2, 4, 6-trimethylbenzoyl diphenylphosphine oxide, and the like.

Further examples of the photopolymerization initiator (E) include:

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

benzophenone compounds such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4 ' -methyldiphenyl sulfide, 3 ', 4, 4 ' -tetrakis (t-butylperoxycarbonyl) benzophenone, 2, 4, 6-trimethylbenzophenone, and 4, 4 ' -bis (N, N ' -dimethylamino) -benzophenone;

xanthone compounds such as 2-isopropylthioxanthone and 2, 4-diethylthioxanthone;

anthracene compounds such as 9, 10-dimethoxyanthracene, 2-ethyl-9, 10-dimethoxyanthracene, 9, 10-diethoxyanthracene, and 2-ethyl-9, 10-diethoxyanthracene;

quinone compounds such as 9, 10-phenanthrenequinone, 2-ethylanthraquinone, camphorquinone, etc.;

benzil, methyl phenylglyoxylate, titanocene compounds, and the like.

The content of the photopolymerization initiator (E) is usually 0.1 mass% or more and 20 mass% or less, and is preferably 0.5 mass% or more and 15 mass% or less, more preferably 1 mass% or more and 10 mass% or less (for example, 8 mass% or less) from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate, assuming that the total amount of the curable composition is 100 mass%.

The content of the photopolymerization initiator (E) is usually 0.1 part by mass or more and 30 parts by mass or less when the total mass of the monofunctional (meth) acrylate compound (B) and the polyfunctional (meth) acrylate compound (C) is 100 parts by mass, and is preferably 0.5 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizing plate.

[ viscosity of curable composition ]

The viscosity of the curable composition at 25 ℃ is preferably 10000mPa sec or less, more preferably 2mPa sec or more and 7000mPa sec or less, and still more preferably 4mPa sec or more and 5000mPa sec or less. The viscosity of the curable composition at 25 ℃ can be measured by an E-type viscometer.

[ moisture permeability of cured film ]

The moisture permeability of the cured film formed from the curable composition is preferably low. A cured film having a thickness of 10 μm formed from the curable composition preferably has a moisture permeability of 400 g/(m) measured by a cup method prescribed in JIS Z0208 at a temperature of 40 ℃ and a relative humidity of 90%²24hr) or less, more preferably 300 g/(m)²24hr) or less, more preferably 200 g/(m)²24hr) or less. The moisture permeability is usually 1 g/(m)²24hr) or more, for example, 5 g/(m)²24hr) above.

The moisture permeability J of the cured film formed from the curable composition can be determined, specifically, by measuring the moisture permeability of a laminate in which the cured film is formed on a substrate film having a known moisture permeability by the above-described method and using the measurement result, based on the following formula.

1/Jt＝(1/J)+(1/Jsub)

In the above formula, Jt is the moisture permeability of the laminate, and Jsub is the moisture permeability of the base film. As the substrate film, the same substrate film as the thermoplastic resin film described later can be used. When the moisture permeability of the laminate was measured in accordance with JIS Z0208, the laminate was mounted in a cup with the cured film facing outward.

The laminate is obtained by using, for example, a (meth) acrylic resin film having a thickness of 60 μm as the base filmIn the case of using a laminate of the (meth) acrylic resin film and a cured film having a thickness of 10 μm and formed from the curable composition, the moisture permeability of the laminate as measured by the cup method specified in JIS Z0208 under the conditions of a temperature of 40 ℃ and a relative humidity of 90% is preferably 55 g/(m%²24hr) or less, more preferably 50 g/(m)²24hr) or less. The moisture permeability is usually 1 g/(m)²24hr) or more, for example, 5 g/(m)²24hr) above.

The thickness of the cured film formed from the curable composition is 10 μm or more, including 10. + -.1 μm or less.

[ use of curable composition ]

The curable composition (or layer) having excellent storage stability and improved adhesion to a polyvinyl alcohol-based polarizing plate is suitable as an adhesive for bonding the polyvinyl alcohol-based polarizing plate and a thermoplastic resin film to each other in a polarizing plate in which the thermoplastic resin film is laminated on at least one surface of the polyvinyl alcohol-based polarizing plate via an adhesive layer.

< polarizing plate >

The polarizing plate of the present invention comprises a polarizer and a thermoplastic resin film laminated on at least one surface thereof via an adhesive layer formed of the curable composition. The adhesive layer is a cured product layer of the curable composition. The polarizing plate may comprise a film or layer other than the polyvinyl alcohol polarizer and the thermoplastic resin film.

In the polarizing plate of the present invention, the polarizing plate and the thermoplastic resin film are bonded to each other by the curable composition, so that the polarizing plate can have good adhesion to the polarizing plate and can have good durability.

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

[1] Structure of polarizing plate

Fig. 1 and 2 show examples of the layer structure of the polarizing plate of the present invention.

As shown in fig. 1, the polarizing plate of the present invention may include a polarizer 30, a1 st adhesive layer 15, and a1 st thermoplastic resin film 10 in this order, that is, may include a polarizer 30 and a1 st thermoplastic resin film 10 laminated and bonded on one surface thereof via the 1 st adhesive layer 15.

The 1 st adhesive layer 15 and the 1 st thermoplastic resin film 10 are preferably in direct contact.

The polarizing plate 30 is preferably in direct contact with the 1 st adhesive layer 15.

As shown in fig. 2, the polarizing plate of the present invention may include a polarizer 30, a1 st thermoplastic resin film 10 laminated and bonded on one surface thereof via a1 st adhesive layer 15, and a2 nd thermoplastic resin film 20 laminated and bonded on the other surface of the polarizer 30 via a2 nd adhesive layer 25.

The 1 st adhesive layer 15 and the 1 st thermoplastic resin film 10 are preferably in direct contact.

The polarizing plate 30 is preferably in direct contact with the 1 st adhesive layer 15.

The 2 nd adhesive layer 25 is preferably in direct contact with the 2 nd thermoplastic resin film 20.

The polarizer 30 is preferably in direct contact with the 2 nd adhesive layer 25.

When the polarizing plate has the 1 st adhesive layer 15 and the 2 nd adhesive layer 25, either one of them may be formed of the curable composition of the present invention, or both adhesive layers may be formed of the curable composition of the present invention.

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

The polarizing plate of the present invention may include other layers (or films) than those described above, without being limited to the examples of fig. 1 and 2. Examples of the other layers include an adhesive layer laminated on the outer surface of the 1 st thermoplastic resin film 10, the 2 nd thermoplastic resin film 20, and/or the polarizing plate 30; a separator (also referred to as a "release film") laminated on an outer surface of the adhesive layer; a protective film (also referred to as a "surface protective film") laminated on an outer surface of the 1 st thermoplastic resin film 10, the 2 nd thermoplastic resin film 20, and/or the polarizing plate 30; and an optical functional film (or layer) laminated on the outer surface of the 1 st thermoplastic resin film 10, the 2 nd thermoplastic resin film 20, and/or the polarizing plate 30 via an adhesive layer or an adhesive layer.

[2] polarizing plate

The polarizing plate 30 is a film having a function of selectively transmitting linearly polarized light in a certain direction from natural light. Examples of the polarizing plate 30 include an iodine-based polarizing plate in which iodine as a dichroic dye is adsorbed to a polyvinyl alcohol-based resin film and is aligned, and a dye-based polarizing plate in which a dichroic dye as a dichroic dye is adsorbed to a polyvinyl alcohol-based resin film and is aligned. These polarizing plates are called absorption polarizing plates because they selectively transmit linearly polarized light in one direction and absorb linearly polarized light in the other direction from natural light.

The polarizer 30 is not limited to the absorption polarizer, and may be a reflection polarizer that selectively transmits linearly polarized light in one direction, reflects linearly polarized light in another direction, or a scattering polarizer that scatters linearly polarized light in another direction from natural light.

The polarizing plate 30 is a polyvinyl alcohol polarizing plate made of a polyvinyl alcohol resin, and is preferably a polyvinyl alcohol polarizing plate in which a polyvinyl alcohol resin film is caused to adsorb and orient a dichroic dye such as iodine or a dichroic dye, and more preferably a polyvinyl alcohol polarizing plate in which a polyvinyl alcohol resin film is caused to adsorb and orient iodine.

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

The thickness of the polarizing plate 30 may be 30 μm or less, preferably 25 μm or less (for example, 20 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, and further preferably 8 μm or less). The thickness of the polarizing plate 30 is usually 2 μm or more. The reduction in the thickness of the polarizer 30 is advantageous for the reduction in thickness of the polarizing plate, and hence, an image display device and the like to which the polarizing plate is applied.

[ 3] A thermoplastic resin film

The 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 may each be a light-transmitting (preferably optically transparent) thermoplastic resin containing polyolefin resins such as a chain polyolefin resin (e.g., a polyethylene resin and a polypropylene resin) and a cyclic polyolefin resin (e.g., a norbornene resin); cellulose ester resins such as triacetyl cellulose and diacetyl cellulose; polyester resins such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; a polycarbonate-based resin; (meth) acrylic resins; or mixtures, copolymers, etc. thereof.

The 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 may be either films which are not stretched or films which are uniaxially or biaxially stretched, respectively. The biaxial stretching may be simultaneous biaxial stretching in which 2 stretching directions are simultaneously stretched, or sequential biaxial stretching in which after stretching in the 1 st direction, stretching in the 2 nd direction is different from that.

The 1 st thermoplastic resin film 10 and/or the 2 nd thermoplastic resin film 20 may be a protective film that serves to protect the polarizing plate 30, or may be a protective film that has both optical functions, such as a retardation film.

For example, a retardation film to which an arbitrary retardation value is given can be produced by stretching a film containing the above thermoplastic resin (uniaxial stretching, biaxial stretching, or the like), or forming a liquid crystal layer on the thermoplastic resin film.

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

In 1 embodiment, the (meth) acrylic resin contains methyl methacrylate as a copolymerization component, or contains methyl methacrylate and methyl acrylate as copolymerization components.

Examples of the other copolymerizable components other than methyl acrylate include: methacrylic acid esters other than methyl methacrylate such as ethyl methacrylate, n-, iso-or tert-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate and 2-hydroxyethyl methacrylate;

acrylic esters such as ethyl acrylate, n-, iso-or tert-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate;

hydroxyalkyl acrylates such as methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and n-, iso-or tert-butyl 2- (hydroxymethyl) acrylate;

unsaturated acids such as methacrylic acid and acrylic acid;

halogenated styrenes such as chlorostyrene and bromostyrene;

substituted styrenes such as vinyltoluene and α -methylstyrene;

unsaturated nitriles such as acrylonitrile and methacrylonitrile;

unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride;

unsaturated imides such as phenylmaleimide and cyclohexylmaleimide; and the like.

The above-mentioned other monofunctional monomers may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

As the other copolymerizable component, a polyfunctional monomer may be used.

Examples of the polyfunctional monomer include: compounds obtained by esterifying both terminal hydroxyl groups of ethylene glycol or its oligomer with (meth) acrylic acid, such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, and tetradecene glycol di (meth) acrylate;

a compound obtained by esterifying both terminal hydroxyl groups of propylene glycol or an oligomer thereof with (meth) acrylic acid;

a compound obtained by esterifying a hydroxyl group of a diol such as neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, or butanediol di (meth) acrylate with (meth) acrylic acid;

a compound obtained by esterifying both terminal hydroxyl groups of bisphenol A, an alkylene oxide adduct of bisphenol A, or a halogen-substituted product thereof with (meth) acrylic acid;

compounds obtained by esterifying polyhydric alcohols such as trimethylolpropane and pentaerythritol with (meth) acrylic acid, and compounds obtained by ring-opening addition of a hydroxyl group at a terminal thereof to an epoxy group of glycidyl (meth) acrylate;

a dibasic acid such as succinic acid, adipic acid, terephthalic acid, phthalic acid, or a halogen-substituted compound thereof, or a compound obtained by ring-opening addition of an epoxy group of glycidyl (meth) acrylate to an alkylene oxide adduct thereof;

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

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

The (meth) acrylic resin may be a resin modified by a reaction between functional groups of the copolymer. Examples of the reaction include an intrachain demethanol condensation reaction of a methyl ester group of methyl (meth) acrylate and a hydroxyl group of methyl 2- (hydroxymethyl) acrylate, and an intrachain dehydration condensation reaction of a carboxyl group of meth) acrylic acid and a hydroxyl group of methyl 2- (hydroxymethyl) acrylate.

The glass transition temperature of the (meth) acrylic resin is preferably 80 ℃ or higher and 160 ℃ or lower. The glass transition temperature can be controlled by adjusting the polymerization ratio of the methacrylate monomer and the acrylate monomer, the carbon chain length of each ester group, the kind of the functional group contained in each ester group, and the polymerization ratio of the polyfunctional monomer to the total monomers.

As a method for increasing the glass transition temperature of a (meth) acrylic resin, a method of introducing a ring structure into the main chain of a polymer is also effective. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure, or a lactone structure. Specific examples thereof include cyclic acid anhydride structures such as glutaric anhydride structures and succinic anhydride structures; a cyclic imide structure such as a glutarimide structure and a succinimide structure; lactone ring structures such as butyrolactone and valerolactone.

The glass transition temperature of the (meth) acrylic resin tends to be higher as the content of the ring structure in the main chain increases.

The cyclic acid anhydride structure and the cyclic imide structure can be introduced by a method of introducing a monomer having a cyclic structure such as maleic anhydride or maleimide by copolymerization; a method of introducing a cyclic acid anhydride structure by dehydration/demethanol condensation after polymerization; a method of introducing a cyclic imide structure by reacting an amino compound.

The resin (polymer) having a lactone ring structure can be obtained by preparing a polymer having a hydroxyl group and an ester group in a polymer chain, and then cyclizing-condensing the hydroxyl group and the ester group in the obtained polymer by heating in the presence of a catalyst such as an organic phosphorus compound if necessary to form a lactone ring structure.

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

The (meth) acrylic resin may contain acrylic rubber particles as an impact modifier from the viewpoints of film formability of the resulting film, impact resistance of the film, and the like. The acrylic rubber particles are particles containing an elastic polymer as an essential component, the elastic polymer is mainly composed of an acrylic ester, and the acrylic rubber particles include particles having a single-layer structure substantially composed of only the elastic polymer and particles having a multi-layer structure comprising 1 layer of the elastic polymer.

Examples of the elastic polymer include crosslinked elastic copolymers obtained by copolymerizing another vinyl monomer and a crosslinkable monomer copolymerizable with an alkyl acrylate as a main component.

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

Examples of the other vinyl monomer copolymerizable with the alkyl acrylate include compounds having 1 polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid esters such as methyl methacrylate; aromatic vinyl compounds such as styrene; vinyl cyanide compounds such as acrylonitrile.

Examples of the crosslinkable monomer include crosslinkable compounds having at least 2 polymerizable carbon-carbon double bonds in the molecule, and more specifically include (meth) acrylates of polyhydric alcohols such as ethylene glycol di (meth) acrylate and butanediol di (meth) acrylate; alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate; divinylbenzene, and the like.

At least one of the 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 is preferably a film containing a (meth) acrylic resin ((meth) acrylic resin film), and the (meth) acrylic resin film is preferably laminated and bonded to the polarizing plate 30 via an adhesive layer formed of the curable composition of the present invention.

The curable composition of the present invention can exhibit particularly good adhesion when the thermoplastic resin film is a (meth) acrylic resin film. Therefore, the curable composition of the present invention can be suitably used for bonding a polarizing plate and a (meth) acrylic resin film.

The (meth) acrylic resin film preferably contains a (meth) acrylic resin as a resin component.

The 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 may be films formed of the same thermoplastic resin or films formed of different thermoplastic resins. The 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 may be the same or different in thickness, presence or absence of an additive, kind thereof, retardation characteristics, and the like.

In 1 embodiment, the 1 st thermoplastic resin film 10 is a (meth) acrylic resin film, and the 2 nd thermoplastic resin film 20 is a polyolefin resin film (preferably a cyclic polyolefin resin film), a cellulose ester resin, or a polyester resin film.

In another embodiment, the 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 are (meth) acrylic resin films.

The 1 st thermoplastic resin film 10 and/or the 2 nd thermoplastic resin film 20 may have a surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antistatic layer, an antifouling layer, and a conductive layer on the outer surface (surface on the opposite side of the polarizing plate 30).

The thickness of each of the 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 is usually 5 μm or more and 200 μm or less, preferably 10 μm or more and 120 μm or less, more preferably 10 μm or more and 85 μm or less, and further preferably 15 μm or more and 65 μm or less. The thickness of each of the 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 may be 50 μm or less, or 40 μm or less. The reduction in thickness of the 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 is advantageous for the reduction in thickness of the polarizing plate, and further, of an image display device or the like to which the polarizing plate is applied.

The surfaces of the 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 to which the curable composition is applied may be subjected to surface modification treatment such as saponification treatment, plasma treatment, corona treatment, primer treatment, or the like, from the viewpoint of improving adhesion.

[4] production of polarizing plate, and adhesive layer

The polarizing plate having the structure shown in fig. 1 can be obtained by laminating and bonding the 1 st thermoplastic resin film 10 on one surface of the polarizer 30 via the 1 st adhesive layer 15, and the 2 nd thermoplastic resin film 20 can be laminated and bonded on the other surface of the polarizer 30 via the 2 nd adhesive layer 25, thereby obtaining the polarizing plate having the structure shown in fig. 2.

In the case of manufacturing a polarizing plate having both the 1 st thermoplastic resin film 10 and the 2 nd thermoplastic resin film 20 (hereinafter, these are also simply referred to collectively as "thermoplastic resin films"), these thermoplastic resin films may be laminated and bonded one by one in stages, or thermoplastic resin films having both surfaces bonded may be laminated and bonded at the same time.

In the polarizing plate having the structure shown in fig. 1, the 1 st adhesive layer 15 is formed of the curable composition of the present invention. The 1 st adhesive layer 15 is a cured product layer of the curable composition of the present invention.

In the polarizing plate having the structure shown in fig. 2, at least one of the 1 st adhesive layer 15 and the 2 nd adhesive layer 25 is formed of the curable composition of the present invention. The 1 st adhesive layer 15 and/or the 2 nd adhesive layer 25 are cured layers of the curable composition of the present invention.

In the polarizing plate having the structure shown in fig. 2, either one of the 1 st adhesive layer 15 and the 2 nd adhesive layer 25 may be formed of the curable composition of the present invention, and the other may be formed of another adhesive composition different from the curable composition of the present invention.

Examples of the other adhesive composition include conventionally known water-based adhesives and active energy ray-curable adhesives.

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

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. When an active energy ray-curable adhesive is used, the adhesive layer of the polarizing plate is a cured layer of the adhesive.

The active energy ray-curable adhesive may be an adhesive containing an epoxy compound that is cured by cationic polymerization as a curable component, and is preferably an ultraviolet-curable adhesive containing the epoxy compound as a curable component. The epoxy compound is a compound having an average of 1 or more, preferably 2 or more, epoxy groups in a molecule. The epoxy compound may be used alone in 1 kind or in combination of 2 or more kinds.

Examples of the epoxy compound include a hydrogenated epoxy compound (glycidyl ether of a polyol having an alicyclic ring) obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating an aromatic ring of an aromatic polyol; aliphatic epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof; and alicyclic epoxy compounds which are epoxy compounds having 1 or more epoxy groups bonded to an alicyclic ring in the molecule.

The active energy ray-curable adhesive may contain, as a curable component, a (meth) acrylic compound having radical polymerizability in place of or together with the epoxy compound. Examples of the (meth) acrylic compound include (meth) acrylate monomers having 1 or more (meth) acryloyloxy groups in the molecule; a (meth) acryloyloxy group-containing compound such as a (meth) acrylate oligomer having at least 2 (meth) acryloyloxy groups in the molecule, which is obtained by reacting 2 or more kinds of functional group-containing compounds.

When the active energy ray-curable adhesive contains an epoxy compound that is cured by cationic polymerization as a curable component, it preferably contains a photo cationic polymerization initiator. Examples of the photo cation polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-arene complexes, and the like.

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

The bonding of the polarizing plate 30 and the thermoplastic resin film may include a step of applying a curable composition to the bonding surface of the polarizing plate 30 and/or the bonding surface of the thermoplastic resin film, or a step of injecting a curable composition between the polarizing plate 30 and the thermoplastic resin film, laminating the films of both via a layer of the curable composition, and pressing the films from above and below using, for example, a bonding roller.

In the formation of the curable composition layer, various coating methods such as a doctor blade, a wire bar, a die coater, a comma type blade coater, and a gravure coater can be used. Further, the polarizing plate 30 and the thermoplastic resin film may be continuously supplied so that the contact surfaces thereof are on the inner side, and the curable composition may be cast therebetween.

Before the application of the curable composition, one or both of the surfaces to be bonded of the polarizing plate 30 and the thermoplastic resin film may be subjected to an easy adhesion treatment (surface activation treatment) such as saponification treatment, corona discharge treatment, plasma treatment, flame treatment, primer treatment, anchor coat treatment, or the like.

In the case of using an active energy ray-curable adhesive, the curable composition layer is cured by irradiation with an active energy ray.

The light source for emitting active energy rays may be any light source that can generate ultraviolet rays, electron beams, X-rays, and the like. In particular, a light source having a light emission distribution at a wavelength of 400nm or less, such as a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, or the like, can be suitably used.

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

The thicknesses of the 1 st adhesive layer 15 and the 2 nd adhesive layer 25 may be the same or different.

Other constituent elements of the polarizing plate [5]

[ 5-1 ] optical functional film

The polarizing plate may be provided with other optical functional films than the polarizer 30 for imparting a desired optical function, and a suitable example thereof is a retardation film.

As described above, the 1 st thermoplastic resin film 10 and/or the 2 nd thermoplastic resin film 20 may also serve as a retardation film, but a retardation film may be laminated in addition to the thermoplastic resin film. In the latter case, the retardation film may be laminated on the outer surface of the 1 st thermoplastic resin film 10 and/or the 2 nd thermoplastic resin film 20 via an adhesive layer or an adhesive layer. Alternatively, a retardation film may be laminated instead of the 1 st thermoplastic resin film 10 or the 2 nd thermoplastic resin film 20. As a specific example, for example, a retardation film is bonded to one surface of the polarizing plate 30 shown in fig. 1, and the other surface of the polarizing plate 30 of the one-sided protective polarizing plate in which the 1 st thermoplastic resin film 10 is bonded to one surface of the polarizing plate 30 is bonded. In this case, the retardation film may be laminated on the surface of the polarizing plate 30 via an adhesive layer or an adhesive layer.

Examples of the retardation film include a birefringent film formed of a stretched film of a thermoplastic resin having light transmittance; a film in which the orientation of discotic liquid crystal or nematic liquid crystal is fixed; a film in which the above-described liquid crystal layer is formed on the base film, and the like.

The base film is usually a film containing a thermoplastic resin, and one example of the thermoplastic resin is a cellulose ester resin such as triacetyl cellulose.

As the thermoplastic resin forming the birefringent film, the thermoplastic resins described in relation to the 1 st and 2 nd thermoplastic resin films 10 and 20 can be used.

Examples of other optical functional films (optical members) that can be included in the polarizing plate include a light-collecting plate, a brightness enhancement film, a reflective layer (reflective film), a semi-transmissive reflective layer (semi-transmissive reflective film), a light-diffusing layer (light-diffusing film), and the like. These are generally provided when the polarizing plate is a polarizing plate 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 an image display element such as a liquid crystal cell or an organic EL element, or another optical member. The adhesive layer may be laminated on the outer surface of the polarizer 30 in the polarizing plate having the structure shown in fig. 1, and may be laminated on the outer surface of the 1 st thermoplastic resin film 10 or the 2 nd thermoplastic resin film 20 in the polarizing plate having the structure shown in fig. 2.

As the adhesive used for the adhesive layer, an adhesive using a base polymer such as a (meth) acrylic resin, a silicone resin, a polyester resin, a polyurethane resin, or a polyether resin can be used. Among them, (meth) acrylic pressure-sensitive adhesives are preferred from the viewpoint of transparency, adhesive force, reliability, weather resistance, heat resistance, reworkability, and the like.

The thickness of the pressure-sensitive adhesive layer is determined by the adhesive strength thereof, and the like, but is suitably in the range of 1 μm to 50 μm, preferably 2 μm to 40 μm.

The polarizing plate may include a release film laminated on an outer surface of the adhesive layer. The separator may be a film containing a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate, or the like. Among them, stretched films of polyethylene terephthalate are preferable.

The pressure-sensitive adhesive layer may contain, as necessary, fillers formed of glass fibers, glass beads, resin beads, metal powder, or other inorganic powder, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents, and the like.

[ 5-3 ] protective film

The polarizing plate may include a protective film for protecting a surface thereof (a surface of a thermoplastic resin film, a surface of a polarizer, etc.). The protective film is peeled off and removed together with the pressure-sensitive adhesive layer included therein after the polarizing plate is attached to, for example, an image display element or another optical member.

The pellicle film is formed, for example, from a base film and an adhesive layer laminated thereon. The above description can be cited with respect to the adhesive layer.

The resin forming the base film may be, for example, a polyethylene resin such as polyethylene, a propylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, or a thermoplastic resin such as a polycarbonate resin. Polyester resins such as polyethylene terephthalate are preferred.

Examples

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

The following ingredients were prepared.

(A-1): c9 series petroleum resin (A-1), trade name "ARKON P-100" available from Mitsuwa chemical industries, Ltd., softening point: 100.5 ℃, Mw: 1600. bromine number of 0.1g/100g and iodine number of 2.36g/100g

(A-2): c9 series petroleum resin (A-2), trade name "ARKON M-100" available from Mitsuwa chemical industries, softening point: 101 ℃ and Mw: 1400. bromine number of 0.8g/100g and iodine number of 8.75g/100g

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

(C-1): propoxylated bisphenol A diacrylate, New Zhongcun chemical industry Co., Ltd "A-BPP-3". A compound represented by the formula:

[ solution 5]

(wherein X represents an ethyleneoxy group, and the average of the sum of m and n is 3.)

(D) The method comprises the following steps Maleic acid-modified polybutadiene, "N4-B-10 MA", manufactured by Synthomer corporation "

(E) The method comprises the following steps Photopolymerization initiator, "Omnirad 184" manufactured by IGM Co "

The iodine value of "ARKON P-100" and "ARKON M-100" and the iodine value of the C9-based petroleum resin (A) of examples 1 to 3 were measured by the following methods in accordance with JIS K0070-1992.

3g of "ARKON P-100" was dissolved in 20mL of cyclohexane to obtain a cyclohexane solution. To the cyclohexane solution obtained above, 25mL of a Vickers reagent (manufactured by Fuji photo film and Wako pure chemical industries, Ltd.; 0.1mol/L iodine monochloride/acetic acid solution) was added to obtain a mixture. The resulting mixture was allowed to stand in the dark for 30 minutes. Thereafter, 20mL of a 1% potassium iodide reagent and 100mL of water were added to the mixture, followed by stirring to obtain a mixed solution. The resulting mixed solution was titrated with a sodium thiosulfate solution indicating 0.1mol/L, and when the color of the mixed solution became light yellow, a 1% starch solution was added. The mixed solution appeared blue. Subsequently, titration was performed with a 0.1mol/L sodium thiosulfate solution, and the point at which the blue color in the mixed solution disappeared and became colorless was regarded as the end point.

The iodine value of "ARKON M-100" was determined in the same manner as in the case of "ARKON P-100" except that "ARKON P-100" was changed to "ARKON M-100". The iodine value of the C9-based petroleum resin of examples 1 to 3 was measured in the same manner as in example 1 to 3 except that "ARKON P-100" was changed to C9-based petroleum resin [ a mixture of C9-based petroleum resin (A-1) and C9-based petroleum resin (A-2) ].

< examples 1 to 3, comparative example 1 >)

The components were added in the amounts shown in table 1, and mixed with stirring to prepare curable compositions. The unit of the blending amount of each component shown in table 1 is part by mass.

(1) Storage stability

The resulting mixture was allowed to stand at 25 ℃ under a relative humidity of 50% for 24 hours, and the appearance of the resulting curable composition was visually confirmed. The results are shown in table 1.

a: good effect

b: white turbidity

(2) Evaluation of moisture permeability

(2-1) preparation of sample for moisture permeability

The thus-prepared curable composition was applied to a corona-treated polymethyl methacrylate film (PMMA) having a thickness of 60 μm using an adhesive application apparatus. The 60 μm polymethyl methacrylate film had a moisture permeability of 70 [ g/(m) under the conditions of a temperature of 40 ℃ and a relative humidity of 90%²·24hr)〕。

An untreated polyethylene terephthalate film (trade name "SOFTSINE" manufactured by Toyo Boseki K.K.) was laminated on the coating layer of the curable composition, and usedThe nip rolls were bonded (pressing pressure: 4.0 MPa). Then, the total cumulative light quantity of irradiation (cumulative quantity of light irradiation intensity in the wavelength region of 320 to 400 nm) is about 200mJ/cm²The coating layer of the curable composition was cured by ultraviolet light (UVB) (measured by a measuring instrument, UV Power PuckII, manufactured by fusion UV Co., Ltd.) to obtain a laminate of PMMA/cured layer of the curable composition (hereinafter also referred to as adhesive layer)/PET. Thereafter, the PET film was peeled off and used as a sample for moisture permeability measurement. The thickness of the adhesive layer was 10.6 μm in example 1, 10 μm in example 2, 9.6 μm in example 3, and 10.6 μm in comparative example 1, in terms of the thickness after curing.

(2-2) method for measuring moisture permeability

The moisture permeability [ g/(m) under the conditions of 40 ℃ and 90% relative humidity was measured by the cup method specified in JIS Z0208²24hr) ]. The results are shown in table 1.

(3) Evaluation of adhesion

(3-1) sample preparation for evaluation of adhesion

2 polarizing plates each having a protective film on one surface were prepared by laminating a polyvinyl alcohol-iodine polarizing Plate (PVA) having a thickness of 25 μm to a cycloolefin film having a thickness of 50 μm with an acrylic adhesive composition.

A curable adhesive composition is applied to one surface of a polarizing plate of one polarizing plate having a protective film on one surface thereof by using an adhesive application device.

The coating layer of the curable adhesive composition and the other polarizing plate surface of the polarizing plate having a protective film on one surface thereof were laminated using a nip roll. Then, the total cumulative light quantity of irradiation (cumulative quantity of light irradiation intensity in the wavelength region of 320 to 400 nm) is about 200mJ/cm²The adhesive layer was cured by ultraviolet light (UVB) (measurement value obtained by UV Power PuckII, manufactured by FusionUV Co., Ltd.) to obtain a sample for measurement having a layer structure of cycloolefin film/adhesive layer/polarizing plate/cured adhesive layer (cured film)/polarizing plate/adhesive layer/cycloolefin film. The thickness of the cured film of the curable adhesive composition was 10 μm.

(3-2) Tpel peeling test method

The prepared sample was cut into a size of 200mm in length by 25mm in width to prepare a test piece for measuring the peel strength between films. A blade of a cutter was inserted between the polarizing plate and the polarizing plate, and the sheet was peeled off by 30mm from the end in the longitudinal direction, and the peeled portion was held by a holding portion of a testing machine. The test piece in this state was subjected to a temperature of 23 ℃ and a relative humidity of 55% in an atmosphere in accordance with JIS K6854-3: 1999 "adhesive-peel adhesion Strength test method-part 3: t-type peeling "was conducted at a nip moving speed of 300 mm/min, and the average peeling force (unit: N/25mm) was determined for a length of 170mm excluding 30mm of the nip portion, and this was used as the peeling strength between PVA films. The measurement time was 24 hours after the production of the laminate by self-control. The results are shown in table 1. In table 1, "material failure" means that the peel strength was very high and the film broke before being peeled off during the test.

[ Table 1]