Curable composition and polarizing plate

Abstract

To provide a curable composition that is excellent in storage stability, and is excellent in adhesion to polyvinyl alcohol-based polarizer when used as an adhesive.SOLUTION: A curable composition contains a C9-based petroleum resin (A) and a monofunctional (meth)acrylate compound (B). The C9-based petroleum resin (A) contains two or more C9-based petroleum resins having different bromine values.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition, and further to a polarizing plate including a cured product layer thereof. [Background technology]

[0002] Polarizing plates widely used in image display devices such as liquid crystal displays and organic electroluminescence (EL) display devices typically have a polarizer with a thermoplastic resin film such as a protective film attached to one or both sides of the polarizer. An adhesive is typically used to attach the polarizer and the thermoplastic resin film. Known examples of such adhesives include active energy ray-curable adhesives and water-based adhesives (Patent Document 1: JP 2009-008860 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-008860 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a curable composition that has good storage stability and exhibits good adhesion to a polyvinyl alcohol-based polarizer when used as an adhesive. [Means for solving the problem]

[0005] The present invention provides the following curable composition and polarizing plate. [1] A curable composition comprising a C9 petroleum resin (A) and a monofunctional (meth)acrylate compound (B), wherein the C9 petroleum resin (A) comprises two or more C9 petroleum resins having different bromine values. [2] The curable composition according to [1], wherein the C9 petroleum resin (A) contains a C9 petroleum resin having a bromine number of less than 0.7 g / 100 g and a C9 petroleum resin having a bromine number of 0.7 g / 100 g or more. [3] A laminate of a 10 μm thick cured film made of the curable composition according to [1] or [2] and a 60 μm thick (meth)acrylic resin film, which has a viscosity of 55 g / (m 2 A laminate with a moisture permeability of 24 hours or less. [4] A polarizing plate comprising a polarizer, an adhesive layer, and a thermoplastic resin film in this order, wherein the adhesive layer is a layer of a cured product of the curable composition according to [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 thickness of the adhesive layer is 2 μm or more and 50 μm or less. [7] A composition comprising a C9 petroleum resin (A') and a monofunctional (meth)acrylate compound (B), The curable composition, wherein the C9 petroleum resin (A') has an iodine value of 2.5 g / 100 g or more and 8 g / 100 g or less. [Effects of the Invention]

[0006] It is possible to provide a curable composition that has good storage stability and exhibits good adhesion to a polyvinyl alcohol-based polarizer when used as an adhesive. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view showing an example of a layer structure of a polarizing plate according to the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the polarizing plate according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all of the drawings, the scales of the components are appropriately adjusted to make them easier to understand, and the scales of the components shown in the drawings do not necessarily match the scales of the actual components.

[0009] <Curable composition> The curable composition according to the present invention (hereinafter also referred to as the "first curable composition") contains a C9 petroleum resin (A) and a monofunctional (meth)acrylate compound (B), and the C9 petroleum resin (A) contains two or more C9 petroleum resins having different bromine values. The curable composition may contain other components in addition to the C9 petroleum resin (A) and the monofunctional (meth)acrylate compound (B). Examples of other components include a polyfunctional (meth)acrylate compound (C), a maleic anhydride-modified compound (D), a photopolymerization initiator (E), curable components 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. A curable composition according to another aspect of the present invention (hereinafter also referred to as a second curable composition) contains a C9 petroleum resin (A') and a monofunctional (meth)acrylate compound (B), and is characterized in that the C9 petroleum resin (A') has an iodine value of 2.5 g / 100 g or more and 8 g / 100 g or less. In this specification, the first curable composition and the second curable composition are collectively referred to as the curable compositions. In this specification, the compounds exemplified as components that are or can be contained in the curable composition can be used alone or in combination of two or more types, unless otherwise specified.

[0010] In this specification, "(meth)acrylate" refers to at least one selected from the group consisting of acrylate and methacrylate. The same applies to expressions such as "(meth)acryloyl" and "(meth)acrylic".

[0011] [1] C9 petroleum resin (A) The C9 petroleum resin (A) contains two or more C9 petroleum resins with different bromine values. When the first curable composition contains two or more C9 petroleum resins with different bromine values, the first curable composition tends to exhibit good storage stability and, when used as an adhesive, tends to exhibit good adhesion to a polyvinyl alcohol-based polarizer. The bromine number of the C9 petroleum resin (A) can be measured in accordance with JIS K 26 05. The bromine number of the C9 petroleum resin (A) is an index representing the hydrogenation rate, and a smaller bromine number indicates a higher hydrogenation rate of the C9 petroleum resin (A).

[0012] The C9 petroleum resin is a resin obtained by copolymerizing a C9 fraction, and may be a hydrogenated or modified version of the resin. The C9 petroleum resin (A) may also contain components other than the C9 fraction, such as a resin (C5C9 petroleum resin) obtained by copolymerizing a C5 fraction with a C9 fraction. Examples of C9 fractions include petroleum fractions having about 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, indene, and methylindene. Examples of C5 fractions include petroleum fractions having about 4 to 5 carbon atoms, such as cyclopentadiene, pentene, pentadiene, and isoprene.

[0013] The number of C9 petroleum resins with different bromine values ​​contained in the C9 petroleum resin (A) may be, for example, 2 to 5, preferably 2 to 4, more preferably 2 or 3, and even more preferably 2.

[0014] When two C9 petroleum resins with different bromine numbers are included, small The bromine value of the C9 petroleum resin (A1) is big The mixing ratio ((A1):(A2)) with the C9 petroleum resin (A2) may be, for example, 50 or more but less than 100: more than 0 but 50 or less by mass, and from the viewpoint of improving storage stability and improving adhesion to polyvinyl alcohol-based polarizers, is preferably 60 or more but 90:10 or more but 40, more preferably 65 or more but 85:15 or more but 35.

[0015] A combination of two C9 petroleum resins with different bromine values ​​is preferably a C9 petroleum resin (A1) with a bromine value of less than 0.5 g / 100 g and a C9 petroleum resin (A2) with a bromine value of 0.7 g / 100 g or more. A more preferred combination is a C9 petroleum resin (A1) with a bromine value of 0.01 g / 100 g or more and less than 0.5 g / 100 g and a C9 petroleum resin (A2) with a bromine value of 0.7 g / 100 g or more and 10 g / 100 g or less. An even more preferred combination is a C9 petroleum resin (A1) with a bromine value of 0.05 g / 100 g or more and less than 0.3 g / 100 g and a C9 petroleum resin (A2) with a bromine value of 0.7 g / 100 g or more and 5 g / 100 g or less.

[0016] The C9 petroleum resin (A) may be a commercially available product, such as Alcon M-100 (manufactured by Arakawa Chemical Industries, Ltd., bromine number 0.8 g / 100 g) or Alcon P-100 (manufactured by Arakawa Chemical Industries, Ltd., bromine number 0.1 g / 100 g).

[0017] The weight-average molecular weight of the C9 petroleum resin (A) is usually from 500 to 10,000, and from the viewpoint of improving storage stability and adhesion to a polyvinyl alcohol polarizer, it is preferably from 500 to 7,000, and more preferably from 600 to 5,000. The weight-average molecular weight of the C9 petroleum resin (A) can be measured as a standard polystyrene-equivalent value by gel permeation chromatography (GPC).

[0018] When the total amount of the first curable composition is taken as 100% by mass, the content of the C9 petroleum resin (A) is preferably from 20% by mass to 70% by mass, and more preferably from 30% by mass to 65% by mass, from the viewpoint of improving storage stability and adhesion to a polyvinyl alcohol polarizer.

[0019] The C9 petroleum resin (A) may have an iodine value (described below) of, for example, 2.5 g / 100 g or more and 8 g / 100 g or less, preferably 3 g / 100 g or more and 7 g / 100 g or less, and more preferably 3.5 g / 100 g or more and 6 g / 100 g or less.

[0020] [2] C9 petroleum resin (A') The iodine value of the C9 petroleum resin (A') is 2.5 g / 100 g or more and 8 g / 100 g or less, preferably 3 g / 100 g or more and 7 g / 100 g or less, and more preferably 3.5 g / 100 g or more and 6 g / 100 g or less. When the second curable composition contains the C9 petroleum resin (A'), the second curable composition tends to exhibit good storage stability and, when used as an adhesive, tends to exhibit good adhesion to a polyvinyl alcohol polarizer. The iodine value of the C9 petroleum resin (A') can be measured by the method described in the Examples.

[0021] The iodine value of the C9 petroleum resin (A') is controlled, for example, by combining two or more petroleum resins having different iodine values. The number of C9 petroleum resins with different iodine values ​​contained in the C9 petroleum resin (A') may be, for example, 2 to 5, preferably 2 to 4, more preferably 2 or 3, and even more preferably 2. When two C9 petroleum resins with different iodine values ​​are contained, the mixing ratio ((A3):(A4)) of the C9 petroleum resin (A3) with the higher iodine value to the C9 petroleum resin (A4) with the lower iodine value may be, for example, 50 or more but less than 100: more than 0 and 50 or less by mass, and from the viewpoints of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizer, is preferably 60 or more but 90:10 or more but 40, and more preferably 65 or more but 85:15 or more but 35. A preferred example of a combination of two C9 petroleum resins with different iodine values ​​is a combination of a C9 petroleum resin (A3) having an iodine value of 0.1 g / 100 g or more and 10 g / 100 g or less and a C9 petroleum resin (A4) having a bromine value of 0.01 g / 100 g or more and 1 g / 100 g or less.

[0022] The above explanations for the C9 petroleum resin (A) apply to commercially available examples of the C9 petroleum resin (A'), its weight average molecular weight, and its content in the second curable composition.

[0023] The C9 petroleum resin (A') may contain two or more C9 petroleum resins. When the C9 petroleum resin (A') contains two or more C9 petroleum resins, the C9 petroleum resins may have different bromine values. The combinations and ratios of C9 petroleum resins with different bromine values ​​are the same as those exemplified and preferred ranges for the C9 petroleum resin (A) described above.

[0024] [3] Monofunctional (meth)acrylate compound (B) The monofunctional (meth)acrylate compound (B) is a radically polymerizable compound having one (meth)acryloyloxy group in the molecule. The curable composition may contain one or more monofunctional (meth)acrylate compounds (B).

[0025] An example of the monofunctional (meth)acrylate compound (B) is an alkyl (meth)acrylate, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, or 2-ethylhexyl (meth)acrylate.

[0026] Other examples of the monofunctional (meth)acrylate compound (B) include aromatic (meth)acrylate compounds in which the group bonded to -O- of the ester bond (-C(=O)-O-) contains an aromatic ring, such as aralkyl (meth)acrylates such as benzyl (meth)acrylate, and phenoxy (meth)acrylates such as 2-phenoxyethyl (meth)acrylate, phenoxyethylene glycol (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 -O- of the ester bond (-C(=O)-O-) contains an alicyclic ring, such as cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, and isobornyl (meth)acrylate; Aminoalkyl (meth)acrylate compounds such as N,N-dimethylaminoethyl (meth)acrylate; (Meth)acrylate compounds in which the group bonded to -O- of the ester bond (-C(=O)-O-) contains an ether bond, such as dicyclopentenyloxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate, other than those mentioned above etc.

[0027] Further examples of the monofunctional (meth)acrylate compound (B) include, for example, (meth)acrylate compounds in which the group bonded to -O- of the ester bond (-C(=O)-O-) contains a hydroxyl group, 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, and pentaerythritol mono(meth)acrylate; (Meth)acrylate compounds in which the group bonded to -O- of the ester bond (-C(=O)-O-) contains a carboxyl group, such as 2-carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone (n≒2) mono(meth)acrylate, 1-[2-(meth)acryloyloxyethyl]phthalic acid, 1-[2-(meth)acryloyloxyethyl]hexahydrophthalic acid, 1-[2-(meth)acryloyloxyethyl]succinic acid, 4-[2-(meth)acryloyloxyethyl]trimellitic acid, and N-(meth)acryloyloxy-N',N'-dicarboxymethyl-p-phenylenediamine. etc.

[0028] By including the monofunctional (meth)acrylate compound (B), the curable composition tends to exhibit good storage stability and tends to easily improve adhesion to a polyvinyl alcohol-based polarizer. From the viewpoint of improving storage stability and adhesion to a polyvinyl alcohol-based polarizer, 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.

[0029] When the total amount of the curable composition is taken as 100% by mass, the content of the monofunctional (meth)acrylate compound (B) is usually from 9% to 75% by mass, preferably from 15% to 70% by mass, more preferably from 20% to 60% by mass, from the viewpoint of improving storage stability and adhesion to a polyvinyl alcohol-based polarizer.

[0030] [4] Polyfunctional (meth)acrylate compound (C) The polyfunctional (meth)acrylate compound (C) is a radical polymerizable compound having two or more (meth)acryloyloxy groups in the molecule. The curable composition may contain only one type of polyfunctional (meth)acrylate compound (C), or may contain two or more types.

[0031] Examples of the polyfunctional (meth)acrylate compound (C) include a bifunctional (meth)acrylate compound (C-1) having two (meth)acryloyloxy groups in the molecule, and a polyfunctional (meth)acrylate compound (C-2) having three or more (meth)acryloyloxy groups in the molecule.

[0032] Examples of the bifunctional (meth)acrylate compound (C-1) include alkylene glycol di(meth)acrylate, polyoxyalkylene glycol di(meth)acrylate, halogen-substituted alkylene glycol di(meth)acrylate, di(meth)acrylate of an aliphatic polyol, di(meth)acrylate of hydrogenated dicyclopentadiene or tricyclodecane dialkanol, di(meth)acrylate of dioxane glycol or dioxane dialkanol, di(meth)acrylate of an alkylene oxide adduct of bisphenol A or bisphenol F, and epoxy di(meth)acrylate of bisphenol A or bisphenol F. acrylates and the like.

[0033] More specific examples of the bifunctional (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, and ditrimethylolpropane di(meth)acrylate. Dipropane 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, polytetramethylene glycol di(meth)acrylate, silicone di(meth)acrylate, neopentyl glycol hydroxypivalate Di(meth)acrylate, 2,2-bis[4-(meth)acryloyloxyethoxyethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane, hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, 1,3-dioxane-2,5-diyl di(meth)acrylate (also known as dioxane glycol di(meth)acrylate), hydroxypivalaldehyde and trimethylolpropane These include the di(meth)acrylate of acetal compound with propane [chemical name: 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane], tris(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, and di(meth)acrylate of propoxylated bisphenol F.

[0034] The bifunctional (meth)acrylate (C-1) 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.

[0035] From the viewpoints of moisture permeability of the cured product and adhesion to a resin film (particularly a (meth)acrylic resin film), the bifunctional (meth)acrylate (C-1) preferably contains a compound represented by the following formula, and more preferably is a compound represented by the following formula: [ka] (In the formula, R1 and R2 each independently represent a hydrogen atom or a methyl group, X represents ethylene oxide (—C2H4O—) or propylene oxide (—C3H6O—), n represents an integer of 1 to 20, and m represents an integer of 1 to 20.) X is preferably ethylene oxide, and the average sum of m and n is preferably 2-20, more preferably 3-15, and particularly preferably 4-13.

[0036] Examples of the polyfunctional (meth)acrylate compound (C-2) having three or more (meth)acryloyloxy groups in the molecule include poly(meth)acrylates of trifunctional or higher aliphatic polyols, such as glycerin tri(meth)acrylate, alkoxylated glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; Poly(meth)acrylates of trifunctional or higher halogen-substituted polyols; Tri(meth)acrylate of alkylene oxide adduct of glycerin; Tri(meth)acrylate of alkylene oxide adduct of trimethylolpropane; 1,1,1-tris[(meth)acryloyloxyethoxyethoxy]propane; Tris(hydroxyethyl)isocyanurate tri(meth)acrylate etc.

[0037] When the total mass of the monofunctional (meth)acrylate compound (B) and the polyfunctional (meth)acrylate compound (C) is taken as 100 mass%, the content of the monofunctional (meth)acrylate compound (B) is usually 60 mass% or more, and from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizer, it is preferably 70 mass% or more, and more preferably 80 mass% or more.

[0038] When the total mass of the monofunctional (meth)acrylate compound (B) and the polyfunctional (meth)acrylate compound (C) is taken as 100% by mass, the content of the monofunctional (meth)acrylate compound (B) is preferably 99% by mass or less, more preferably 98% by mass or less, and may be 90% by mass or less, from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizer.

[0039] [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 one or more maleic anhydride-modified compounds (D) from the viewpoints of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizer when used as an adhesive. The maleic anhydride-modified compound (D) may include a maleic anhydride-modified polymer (D-1).

[0040] The maleic anhydride-modified polymer (D-1) is a polymer modified by introducing a maleic anhydride structure as a side chain of the polymer. The curable composition may contain only one type of maleic anhydride-modified polymer (D-1), or may contain two or more types.

[0041] The maleic anhydride structure refers to the following structure. [ka] (* indicates a bond to the main chain.)

[0042] In the maleic anhydride-modified polymer (D-1), examples of the polymer to be modified with maleic anhydride include diene polymers, polyolefin polymers, (meth)acrylic 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.

[0043] The maleic anhydride-modified polymer (D-1) is preferably in a liquid state, since this allows the preparation of a solvent-free curable composition with good adhesive properties. The term "liquid" means that the polymer exhibits fluidity at a temperature of 25°C. The viscosity of the liquid maleic anhydride-modified polymer (D-1) at 25°C is preferably 10 Pa·sec or more and 10,000 Pa·sec or less, more preferably 15 Pa·sec or more and 7,000 Pa·sec or less, from the viewpoint of obtaining a curable composition with good coatability. Preferred examples of the liquid maleic anhydride-modified polymer (D-1) include, for example, maleic anhydride-modified polybutadiene, maleic anhydride-modified polyisoprene, and maleic anhydride-modified polyisobutylene. Each of these polymers may be a homopolymer or a copolymer. In the case of a copolymer, the copolymerization monomer is, for example, an olefin monomer.

[0044] The number average molecular weight of the maleic anhydride modified polymer (D-1) is usually 500 or more and 15,000 or less, and from the viewpoint of viscosity and coatability, it is preferably 600 or more and 12,000 or less, more preferably 700 or more and 10,000 or less. The number average molecular weight of the maleic anhydride-modified polymer (D-1) can be measured as a value converted into standard polystyrene by gel permeation chromatography (GPC).

[0045] The acid value of the maleic anhydride-modified polymer (D-1) is usually 10 KOHmg / g or more and 200 KOHmg / g or less, and from the viewpoint of the adhesive ability of the curable composition to a thermoplastic resin film (or layer), it is preferably 15 KOHmg / g or more and 150 KOHmg / g or less, more preferably 20 KOHmg / g or more and 100 KOHmg / g or less, even more preferably 30 KOHmg / g or more and 100 KOHmg / g or less, and particularly preferably 45 KOHmg / g or more and 100 KOHmg / g or less. The acid value of the maleic anhydride modified polymer (D-1) is measured by neutralization titration using phenolphthalein as an indicator in accordance with JIS K 0070:1992.

[0046] When the total amount of the curable composition is taken as 100% by mass, the content of the maleic anhydride-modified compound (D) is usually 3% by mass or more and 40% by mass or less, and from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizer, it is preferably 5% by mass or more and 35% by mass or less, and more preferably 10% by mass or more and 30% by mass or less.

[0047] [6] Photopolymerization initiator (E) The photopolymerization initiator (E) is not particularly limited as long as it is a compound that generates active radicals, acids, etc. by the action of light and can initiate polymerization of the monofunctional (meth)acrylate compound (B). The photopolymerization initiator (E) is preferably a compound that can also initiate polymerization of the polyfunctional (meth)acrylate compound (C). The curable composition may contain only one type of photopolymerization initiator (E), or may contain two or more types.

[0048] The photopolymerization initiator (E) is not particularly limited, but examples thereof include oxime compounds such as O-acyloxime compounds, alkylphenone compounds, and acylphosphine oxide compounds.

[0049] An O-acyloxime compound is a compound having a structure represented by the following formula (d): Hereinafter, * represents a bond.

[0050] [ka]

[0051] Examples of O-acyloxime compounds 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-cyclopentylpropan-1-one-2-imine, N-acetoxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethan-1-imine, and N-acetoxy-1-[9-ethyl-6-{2-methyl-4-(3,3-dimethyl-2,4-dioxacyclopentanylmethyloxy)benzoyl}-9H-carbazol-3-yl] Examples include ethan-1-imine, N-acetoxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-3-cyclopentylpropan-1-imine, N-benzoyloxy-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-3-cyclopentylpropan-1-one-2-imine, N-acetyloxy-1-[4-(2-hydroxyethyloxy)phenylsulfanylphenyl]propan-1-one-2-imine, and N-acetyloxy-1-[4-(1-methyl-2-methoxyethoxy)-2-methylphenyl]-1-(9-ethyl-6-nitro-9H-carbazol-3-yl)methane-1-imine. Commercially available products such as Irgacure (trade name) OXE01, OXE02, and OXE03 (all manufactured by BASF), N-1919, NCI-930, and NCI-831 (all manufactured by ADEKA) may also be used.

[0052] 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.

[0053] [ka]

[0054] Examples of compounds having a structure represented by 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-morpholinyl)phenyl]butan-1-one. Omnirad (product name) 369, Omnirad 907, Omnirad 379 (and above, IGM Resins Commercially available products such as those manufactured by BV may also be used.

[0055] Examples of compounds having a 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,α-diethoxyacetophenone, and benzyl dimethyl ketal. Commercially available products such as Omnirad (trade name) 184 (manufactured by IGM Resins BV) may also be used.

[0056] Examples of the acylphosphine oxide compound include phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (for example, trade name "Omnirad 819" (manufactured by IGM Resins BV)), 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like.

[0057] 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, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, and 4,4'-di(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, and camphorquinone; Benzyl, methyl phenylglyoxylate, titanocene compounds etc.

[0058] When the total amount of the curable composition is taken as 100% by mass, the content of the photopolymerization initiator (E) is usually from 0.1% by mass to 20% by mass, and from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizer, it is preferably from 0.5% by mass to 15% by mass, and more preferably from 1% by mass to 10% by mass (for example, 8% by mass).

[0059] When the total mass of the monofunctional (meth)acrylate compound (B) and the polyfunctional (meth)acrylate compound (C) is taken as 100 parts by mass, the content of the photopolymerization initiator (E) is usually 0.1 parts by mass or more and 30 parts by mass or less, and from the viewpoint of improving storage stability and improving adhesion to a polyvinyl alcohol-based polarizer, it is preferably 0.5 parts by mass or more and 20 parts by mass or less, and more preferably 1 part by mass or more and 10 parts by mass or less.

[0060] [Viscosity of curable composition] The viscosity of the curable composition at 25°C is preferably 10,000 mPa·sec or less, more preferably 2 mPa·sec or more and 7,000 mPa·sec or less, and even more preferably 4 mPa·sec or more and 5,000 mPa·sec or less. The viscosity of the curable composition at 25°C can be measured using an E-type viscometer.

[0061] [Moisture permeability of cured film] The moisture permeability of a cured film formed from the curable composition is preferably low. A 10 μm thick cured film made of the curable composition preferably has a moisture permeability of 400 g / (m) as measured by the cup method specified in JIS Z 0208 under conditions of a temperature of 40° C. and a relative humidity of 90%. 2 24hr) or less, and more preferably 300g / (m 2 24hr) or less, and more preferably 200g / (m 2 The moisture permeability is usually 1 g / (m 2 24hr) or more, for example, 5g / (m 2 24 hours or more.

[0062] Specifically, the moisture permeability J of a cured film made of a curable composition can be calculated by producing a laminate in which the cured film is formed on a substrate film having a known moisture permeability, measuring the moisture permeability of the laminate by the above-mentioned method, and then using the measurement results 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. The base film can be the same as the thermoplastic resin film described below. When measuring the moisture permeability of the laminate according to JIS Z 0208, the laminate is attached to a cup with the cured film facing outward.

[0063] In the case where a (meth)acrylic resin film having a thickness of, for example, 60 μm is used as the base film in the above laminate, a laminate of the (meth)acrylic resin film and a cured film having a thickness of 10 μm made of a curable composition preferably has a moisture permeability of 55 g / (m) as measured by the cup method specified in JIS Z 0208 under conditions of a temperature of 40°C and a relative humidity of 90%. 2 24hr) or less, and more preferably 50g / (m 2 The moisture permeability is usually 1 g / (m 2 24hr) or more, for example, 5g / (m 2 24 hours or more. The thickness of the cured film made of the curable composition of 10 μm includes a thickness of 10±1 μm.

[0064] [Uses of the curable composition] A curable composition (or layer) that has excellent storage stability and improved adhesion to a polyvinyl alcohol-based polarizer is suitable as an adhesive for bonding a polyvinyl alcohol-based polarizer and a thermoplastic resin film in a polarizing plate in which a thermoplastic resin film is laminated on at least one surface of a polyvinyl alcohol-based polarizer via an adhesive layer.

[0065] <Polarizing plate> The polarizing plate according to the present invention includes a polarizer and a thermoplastic resin film laminated on at least one surface of the polarizer via an adhesive layer formed from the curable composition. The adhesive layer is a cured product layer of the curable composition. The polarizing plate may include a film or layer other than the polyvinyl alcohol-based polarizer and the thermoplastic resin film.

[0066] The polarizing plate of the present invention has a polarizer and a thermoplastic resin film bonded together using the curable composition, and therefore can have good adhesion to the polarizer, thereby improving the durability of the polarizing plate.

[0067] The polarizing plate according to the present invention can be suitably used in image display devices such as liquid crystal display devices and organic EL devices.

[0068] [1] Polarizing plate configuration Examples of the layer structure of the polarizing plate according to the present invention are shown in FIGS. As shown in FIG. 1, the polarizing plate of the present invention can include a polarizer 30, a first adhesive layer 15, and a first thermoplastic resin film 10 in this order, i.e., a polarizer 30 and a first thermoplastic resin film 10 laminated to one surface of the polarizer 30 via a first adhesive layer 15. It is preferable that the first adhesive layer 15 and the first thermoplastic resin film 10 are in direct contact with each other. The polarizer 30 and the first adhesive layer 15 are preferably in direct contact with each other.

[0069] As shown in FIG. 2, the polarizing plate of the present invention may also include a polarizer 30, a first thermoplastic resin film 10 laminated to one surface of the polarizer 30 via a first adhesive layer 15, and a second thermoplastic resin film 20 laminated to the other surface of the polarizer 30 via a second adhesive layer 25. It is preferable that the first adhesive layer 15 and the first thermoplastic resin film 10 are in direct contact with each other. The polarizer 30 and the first adhesive layer 15 are preferably in direct contact with each other. It is preferable that the second adhesive layer 25 and the second thermoplastic resin film 20 are in direct contact with each other. The polarizer 30 and the second adhesive layer 25 are preferably in direct contact with each other.

[0070] When the polarizing plate has a first adhesive layer 15 and a second adhesive layer 25, either one of them may be formed from the curable composition of the present invention, or both adhesive layers may be formed from the curable composition of the present invention. When both adhesive layers are formed from the curable composition according to the present invention, these curable compositions may have the same composition or different compositions.

[0071] 1 and 2, the polarizing plate according to the present invention may include layers (or films) other than those described above. Examples of such layers include a pressure-sensitive adhesive layer laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, and / or the polarizer 30; a separate film (also referred to as a "release film") laminated on the outer surface of the pressure-sensitive adhesive layer; a protective film (also referred to as a "surface protection film") laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, and / or the polarizer 30; and an optically functional film (or layer) laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, and / or the polarizer 30 via an adhesive layer or a pressure-sensitive adhesive layer.

[0072] [2] Polarizer The polarizer 30 is a film that has the function of selectively transmitting linearly polarized light in one direction from natural light. Examples of polarizer 30 include iodine-based polarizers in which iodine as a dichroic pigment is adsorbed and oriented in a polyvinyl alcohol-based resin film, and dye-based polarizers in which a dichroic dye as a dichroic pigment is adsorbed and oriented in a polyvinyl alcohol-based resin film. These polarizers are called absorptive polarizers because they selectively transmit linearly polarized light in one direction from natural light and absorb linearly polarized light in the other direction.

[0073] The polarizer 30 is not limited to an absorptive polarizer, and may be a reflective polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects linearly polarized light in the other direction, or a scattering polarizer that scatters linearly polarized light in the other direction. However, an absorptive polarizer is preferred because it provides excellent visibility when the polarizing plate is applied to an image display device or the like. The polarizer 30 is a polyvinyl alcohol-based polarizer made of a polyvinyl alcohol-based resin, and is preferably a polyvinyl alcohol-based polarizer in which a dichroic pigment such as iodine or a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based resin film, and more preferably a polyvinyl alcohol-based polarizer in which iodine is adsorbed and oriented in a polyvinyl alcohol-based resin film. A polyvinyl alcohol-based polarizer can be produced by a conventionally known method using a polyvinyl alcohol-based resin film (or layer).

[0074] The thickness of the polarizer 30 can be 30 μm or less, and is preferably 25 μm or less (for example, 20 μm or less, further 15 μm or less, further 10 μm or less, and further 8 μm or less). The thickness of the polarizer 30 is usually 2 μm or more. Reducing the thickness of the polarizer 30 is advantageous for reducing the thickness of the polarizing plate, and therefore the image display device to which it is applied.

[0075] [3] Thermoplastic resin film The first thermoplastic resin film 10 and the second thermoplastic resin film 20 can each be a film made of a light-transmitting (preferably optically transparent) thermoplastic resin, for example, a polyolefin resin such as a chain polyolefin resin (polyethylene resin, polypropylene resin, etc.) or a cyclic polyolefin resin (norbornene resin, etc.); a cellulose ester resin such as triacetyl cellulose or diacetyl cellulose; a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, or polybutylene terephthalate; a polycarbonate resin; a (meth)acrylic resin; or a mixture, copolymer, or the like thereof.

[0076] The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may each be an unstretched film, or a uniaxially or biaxially stretched film. The biaxial stretching may be simultaneous biaxial stretching in which the film is stretched in two stretching directions at the same time, or sequential biaxial stretching in which the film is stretched in a first direction and then stretched in a second direction different from the first direction. The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may be a protective film that plays a role in protecting the polarizer 30, or may be a protective film that also has an optical function such as a retardation film. For example, a film made of the above-mentioned thermoplastic resin may be stretched (uniaxially or biaxially stretched, etc.) or a liquid crystal layer or the like may be formed on the thermoplastic resin film, thereby making it possible to obtain a retardation film having an arbitrary retardation value.

[0077] The (meth)acrylic resin may be, for example, a polymer containing a methacrylic acid ester as the main monomer (containing 50% by mass or more), and is preferably a copolymer in which a methacrylic acid ester is copolymerized with another copolymerization component. In one embodiment, the (meth)acrylic resin contains methyl methacrylate or methyl methacrylate and methyl acrylate as copolymerization components.

[0078] Examples of copolymerization components other than methyl acrylate include methacrylic acid esters other than methyl methacrylate, such as ethyl methacrylate, n-, i-, or t-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate; acrylic acid esters such as ethyl acrylate, n-, i- or t-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate; hydroxyalkyl acrylates such as methyl 2-(hydroxymethyl)acrylate, methyl 2-(1-hydroxyethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, and n-, i-, or t-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 monofunctional monomers. The other monofunctional monomers may be used alone or in combination of two or more.

[0079] A polyfunctional monomer may be used as the other copolymerization component. 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, nonaethylene glycol di(meth)acrylate, and tetradecaethylene glycol di(meth)acrylate, and other ethylene glycol or oligomers thereof in which both terminal hydroxyl groups are esterified with (meth)acrylic acid; Propylene glycol or its oligomers in which both terminal hydroxyl groups have been esterified with (meth)acrylic acid; dihydric alcohols such as neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, and butanediol di(meth)acrylate, whose hydroxyl groups are esterified with (meth)acrylic acid; Bisphenol A, alkylene oxide adducts of bisphenol A, or halogen-substituted products thereof in which both terminal hydroxyl groups have been esterified with (meth)acrylic acid; Esters of polyhydric alcohols such as trimethylolpropane and pentaerythritol with (meth)acrylic acid, and products in which the epoxy group of glycidyl (meth)acrylate is ring-opened and added to the terminal hydroxyl groups of these esters; Dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, and halogen-substituted derivatives thereof, or alkylene oxide adducts thereof, to which an epoxy group of glycidyl (meth)acrylate is ring-opened and added; Aryl (meth)acrylates; aromatic divinyl compounds such as divinylbenzene; etc. Of these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

[0080] The (meth)acrylic resin may be modified by a reaction between functional groups of the copolymer, such as an intrapolymer chain methanol condensation reaction between the methyl ester group of methyl (meth)acrylate and the hydroxyl group of methyl 2-(hydroxymethyl)acrylate, or an intrapolymer chain dehydration condensation reaction between the carboxyl group of (meth)acrylic acid and the hydroxyl group of methyl 2-(hydroxymethyl)acrylate.

[0081] The glass transition temperature of the (meth)acrylic resin is preferably 80° C. or higher and 160° C. or lower. The glass transition temperature can be controlled by adjusting the polymerization ratio of the methacrylic acid ester monomer and the acrylic acid ester monomer, the carbon chain length of each ester group and the type of functional group therein, and the polymerization ratio of the polyfunctional monomer to the total monomers.

[0082] Introducing a ring structure into the main chain of the polymer is also an effective means for increasing the glass transition temperature of the (meth)acrylic resin. 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 include cyclic acid anhydride structures such as glutaric anhydride structures and succinic anhydride structures; cyclic imide structures such as glutarimide structures and succinimide structures; and lactone ring structures such as butyrolactone and valerolactone. The glass transition temperature of the (meth)acrylic resin tends to increase 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 copolymerizing a monomer having a cyclic structure, such as maleic anhydride or maleimide; by introducing the cyclic acid anhydride structure by a dehydration / demethanolization condensation reaction after polymerization; or by reacting an amino compound to introduce a cyclic imide structure. A resin (polymer) having a lactone ring structure can be obtained by preparing a polymer having a hydroxyl group and an ester group in the polymer chain, and then cyclocondensing the hydroxyl group and the ester group in the obtained polymer by heating, if necessary in the presence of a catalyst such as an organic phosphorus compound, to form a lactone ring structure.

[0083] The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may contain additives as needed, such as lubricants, antiblocking agents, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, impact modifiers, surfactants, and the like.

[0084] The (meth)acrylic resin may contain acrylic rubber particles as an impact modifier from the viewpoint of film formability, impact resistance of the film, etc. The acrylic rubber particles are particles containing an acrylic acid ester-based elastic polymer as an essential component, and examples thereof include those with a single-layer structure essentially consisting of this elastic polymer, and those with a multi-layer structure having this elastic polymer as one layer. Examples of the elastic polymer include crosslinked elastic copolymers which contain alkyl acrylate as the main component and are copolymerized with other copolymerizable vinyl monomers and crosslinkable monomers. Examples of alkyl acrylates that are the main component of the elastic polymer include those in which the alkyl group has 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and alkyl acrylates having an alkyl group with 4 or more carbon atoms are preferably used. Examples of other vinyl monomers copolymerizable with the alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, examples thereof include methacrylic acid esters such as methyl methacrylate; aromatic vinyl compounds such as styrene; and vinyl cyanide compounds such as acrylonitrile. Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specific examples 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.

[0085] At least one of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is preferably a film containing a (meth)acrylic resin (a (meth)acrylic resin film), and the (meth)acrylic resin film is preferably laminated to the polarizer 30 via an adhesive layer formed from the curable composition according to the present invention. The curable composition according to the present invention can exhibit particularly good adhesion when the thermoplastic resin film is a (meth)acrylic resin film, and therefore can be suitably used for bonding a polarizer and a (meth)acrylic resin film. The (meth)acrylic resin film preferably contains a resin component made of a (meth)acrylic resin.

[0086] The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be films made of the same thermoplastic resin or films made of different thermoplastic resins. The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be the same or different in terms of thickness, the presence or absence and type of additives, retardation properties, etc. 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), a cellulose ester resin, or a polyester resin film. In another embodiment, the first thermoplastic resin film 10 and the second thermoplastic resin film 20 are (meth)acrylic resin films.

[0087] The first thermoplastic resin film 10 and / or the second 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, or a conductive layer on its outer surface (the surface opposite the polarizer 30).

[0088] The thickness of each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is typically 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 even more preferably 15 μm or more and 65 μm or less. The thickness of each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may 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 is advantageous for reducing the thickness of polarizing plates, and ultimately image display devices to which they are applied.

[0089] The surfaces of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 to which the curable composition is applied may be subjected to surface modification treatments such as saponification treatment, plasma treatment, corona treatment, and primer treatment in order to improve adhesion.

[0090] [4] Manufacture of polarizing plates and adhesive layers A polarizing plate having the configuration shown in Figure 1 can be obtained by laminating and adhering a first thermoplastic resin film 10 to one surface of the polarizer 30 via a first adhesive layer 15, and a polarizing plate having the configuration shown in Figure 2 can be obtained by further laminating and adhering a second thermoplastic resin film 20 to the other surface of the polarizer 30 via a second adhesive layer 25. When manufacturing a polarizing plate having both a first thermoplastic resin film 10 and a second thermoplastic resin film 20 (hereinafter, these are collectively referred to simply as "thermoplastic resin films"), these thermoplastic resin films may be laminated and bonded one side at a time in stages, or the thermoplastic resin films on both sides may be laminated and bonded simultaneously.

[0091] 1, the first adhesive layer 15 is formed from the curable composition according to the present invention. The first adhesive layer 15 is a layer of the cured product of the curable composition according to the present invention. 2, at least one of the first adhesive layer 15 and the second adhesive layer 25 is formed from the curable composition according to the present invention. The first adhesive layer 15 and / or the second adhesive layer 25 is a layer of the cured product of the curable composition according to the present invention.

[0092] In a polarizing plate having the configuration shown in Figure 2, one of the first adhesive layer 15 and the second adhesive layer 25 may be formed from the curable composition of the present invention, and the other may be formed from an adhesive composition other than the curable composition of the present invention. Other adhesive compositions include conventionally known water-based adhesives or active energy ray-curable adhesives.

[0093] Examples of the water-based adhesive include conventionally known adhesive compositions that use a polyvinyl alcohol resin or a urethane resin as the main component.

[0094] An 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, X-rays, etc. When an active energy ray-curable adhesive is used, the adhesive layer of the polarizing plate is a cured product layer of the adhesive.

[0095] The active energy ray-curable adhesive may be an adhesive containing an epoxy compound that cures by cationic polymerization as a curable component, and is preferably an ultraviolet-curable adhesive containing such an epoxy compound as a curable component. The epoxy compound refers to a compound having an average of one or more, preferably two or more, epoxy groups in the molecule. Only one type of epoxy compound may be used, or two or more types may be used in combination.

[0096] Examples of epoxy compounds include hydrogenated epoxy compounds (glycidyl ethers of polyols having alicyclic rings) obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating the aromatic rings of an aromatic polyol; aliphatic epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts; and alicyclic epoxy compounds, which are epoxy compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule.

[0097] The active energy ray-curable adhesive may contain a radically polymerizable (meth)acrylic compound as a curable component, instead of or in addition to the epoxy compound. Examples of the (meth)acrylic compound include (meth)acryloyloxy group-containing compounds such as (meth)acrylate monomers having one or more (meth)acryloyloxy groups in the molecule, and (meth)acrylate oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth)acryloyloxy groups in the molecule.

[0098] When the active energy ray-curable adhesive contains an epoxy compound that cures by cationic polymerization as a curable component, it preferably contains a photocationic polymerization initiator. Examples of the photocationic polymerization initiator include aromatic diazonium salts, onium salts such as aromatic iodonium salts and aromatic sulfonium salts, and iron-allene complexes. When the active energy ray-curable adhesive contains a radically polymerizable component such as a (meth)acrylic compound, it preferably contains a photoradical polymerization initiator. Examples of the photoradical polymerization initiator include acetophenone-based initiators, benzophenone-based initiators, benzoin ether-based initiators, thioxanthone-based initiators, xanthone, fluorenone, camphorquinone, benzaldehyde, and anthraquinone.

[0099] The adhesion between the polarizer 30 and the thermoplastic resin film can include a process of applying a curable composition to the bonding surface of the polarizer 30 and / or the bonding surface of the thermoplastic resin film, or injecting a curable composition between the polarizer 30 and the thermoplastic resin film, overlapping the two films with the layer of curable composition interposed therebetween, and pressing them together from above and below using, for example, a laminating roll.

[0100] The curable composition layer can be formed by various coating methods, such as a doctor blade, a wire bar, a die coater, a comma coater, a gravure coater, etc. Alternatively, the curable composition may be cast between the polarizer 30 and the thermoplastic resin film while the polarizer 30 and the thermoplastic resin film are continuously supplied so that the bonding surfaces of the two face inward.

[0101] Before applying the curable composition, one or both of the bonding surfaces of the polarizer 30 and the thermoplastic resin film may be subjected to an adhesion-enhancing treatment (surface activation treatment) such as saponification treatment, corona discharge treatment, plasma treatment, flame treatment, primer treatment, or anchor coating treatment.

[0102] When an active energy ray-curable adhesive is used, the curable composition layer is cured by irradiating it with active energy rays. The light source used for irradiating the active energy rays may be any light source capable of generating ultraviolet rays, electron beams, X-rays, etc. In particular, light sources having an emission distribution of wavelengths of 400 nm or less, such as 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, and metal halide lamps, are preferably used.

[0103] The thickness of the adhesive layer formed from the curable composition according to the present invention in the polarizing plate is, for example, from 0.1 μm to 100 μm, preferably from 0.5 μm to 80 μm, more preferably from 1 μm to 60 μm, and even more preferably from 2 μm to 50 μm. From the viewpoint of thinning the polarizing plate, it is also preferable that the thickness of the adhesive layer is 30 μm or less, and further preferably 20 μm or less. The first adhesive layer 15 and the second adhesive layer 25 may have the same thickness or different thicknesses.

[0104] [5] Other components of polarizing plates [5-1] Optically functional films The polarizing plate may include an optically functional film other than the polarizer 30 in order to impart a desired optical function, and a suitable example thereof is a retardation film. As described above, the first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 can also serve as a retardation film. Alternatively, a retardation film can be laminated separately from the thermoplastic resin film. In the latter case, the retardation film can be laminated on the outer surface of the first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 via a pressure-sensitive adhesive layer or an adhesive layer. Alternatively, a retardation film can be laminated instead of the first thermoplastic resin film 10 or the second thermoplastic resin film 20. A specific example of such a configuration is shown in FIG. 1 , where a single-sided protected polarizing plate has a first thermoplastic resin film 10 laminated to one surface of the polarizer 30, and a retardation film is laminated to the other surface of the polarizer 30. In this case, the retardation film can be laminated on the surface of the polarizer 30 via a pressure-sensitive adhesive layer or an adhesive layer.

[0105] Examples of the retardation film include a birefringent film made of a stretched film of a light-transmitting thermoplastic resin; a film in which discotic liquid crystal or nematic liquid crystal is oriented and fixed; and a film in which the above-mentioned liquid crystal layer is formed on a substrate film. The substrate film is usually a film made of a thermoplastic resin, and an example of the thermoplastic resin is a cellulose ester resin such as triacetyl cellulose. As the thermoplastic resin for forming the birefringent film, those described for the first and second thermoplastic resin films 10 and 20 can be used.

[0106] Examples of other optically functional films (optical members) that can be included in the polarizing plate include a light collecting plate, a brightness enhancing film, a reflective layer (reflective film), a semi-transmissive reflective layer (semi-transmissive reflective film), a light diffusing layer (light diffusing film), etc. These are generally provided when the polarizing plate is a polarizing plate that is disposed on the back side (backlight side) of the liquid crystal cell.

[0107] [5-2] Adhesive layer The polarizing plate according to the present invention may include a pressure-sensitive adhesive layer for attaching it to an image display element such as a liquid crystal cell or an organic EL element, or to other optical components. The pressure-sensitive adhesive layer may be laminated on the outer surface of the polarizer 30 in the polarizing plate having the configuration shown in Fig. 1, or on the outer surface of the first thermoplastic resin film 10 or the second thermoplastic resin film 20 in the polarizing plate having the configuration shown in Fig. 2.

[0108] The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer may be one having a base polymer such as a (meth)acrylic resin, a silicone resin, a polyester resin, a polyurethane resin, or a polyether resin. Among these, (meth)acrylic pressure-sensitive adhesives are preferred from the viewpoints of transparency, adhesive strength, reliability, weather resistance, heat resistance, reworkability, etc.

[0109] The thickness of the pressure-sensitive adhesive layer is determined depending on its adhesive strength and the like, but is suitably in the range of 1 μm to 50 μm, preferably 2 μm to 40 μm.

[0110] The polarizing plate may include a separate film laminated on the outer surface of the pressure-sensitive adhesive layer. The separate film may be a film made of a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, or a polyester-based resin such as polyethylene terephthalate. Of these, a stretched polyethylene terephthalate film is preferred.

[0111] The pressure-sensitive adhesive layer may contain, as needed, fillers such as glass fibers, glass beads, resin beads, metal powders and other inorganic powders, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents and the like.

[0112] [5-3] Protective film The polarizing plate may contain a protective film for protecting its surface (such as the thermoplastic resin film surface or the polarizer surface.) After the polarizing plate is attached to, for example, an image display element or other optical components, the protective film is peeled off and removed together with its pressure-sensitive adhesive layer.

[0113] The protective film is composed of, for example, a substrate film and an adhesive layer laminated thereon. The adhesive layer is as described above. The resin constituting the base film may be, for example, a thermoplastic resin such as a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate, or a polycarbonate-based resin. A polyester-based resin such as polyethylene terephthalate is preferred. [Example]

[0114] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, % and parts representing the content or amount used are by mass unless otherwise specified.

[0115] The following ingredients were prepared: (A-1): C9 petroleum resin (A-1), trade name "Alcon P-100" manufactured by Arakawa Chemical Industries, Ltd., softening point: 100.5°C, Mw: 1600, bromine value: 0.1g / 100g, iodine value: 2.36g / 100g (A-2): C9 petroleum resin (A-2), trade name "Alcon M-100" manufactured by Arakawa Chemical Industries, Ltd., softening point: 101°C, Mw: 1400, bromine value: 0.8g / 100g, iodine value: 8.75g / 100g (B-1): Dicyclopentanyl acrylate, product name "FA-513AS" manufactured by Hitachi Chemical Co., Ltd. (C-1): Propoxylated bisphenol A diacrylate, "A-BPP-3" manufactured by Shin-Nakamura Chemical Co., Ltd., having the following formula: [ka] (In the formula, X represents ethylene oxide, and the average of the sum of m and n is 3.) A compound represented by the formula: (D): Maleic acid modified polybutadiene, "N4-B-10MA" manufactured by Synthomer (E): Photopolymerization initiator, "Omnirad 184" manufactured by IGM

[0116] The iodine values ​​of "Arcon P-100", "Arcon M-100" and the C9 petroleum resin of Examples 1-3 were measured according to JIS K0070-1992 by the following method. 3 g of "Alcon P-100" was dissolved in 20 mL of cyclohexane to obtain a cyclohexane solution. 25 mL of Wiess's reagent (Fujifilm Wako Pure Chemical Industries, Ltd.; 0.1 mol / L iodine monochloride-acetic acid solution) was added to the resulting cyclohexane solution to obtain a mixture. The resulting mixture was left standing in the dark for 30 minutes. 20 mL of 1% potassium iodide reagent and 100 mL of water were then added to the mixture and stirred to obtain a mixed solution. The resulting mixed solution was titrated with 0.1 mol / L sodium thiosulfate solution. When the mixed solution turned light yellow, 1% starch solution was added. The mixed solution turned blue. Further titration was performed with 0.1 mol / L sodium thiosulfate solution. The endpoint was when the blue color of the mixed solution disappeared and became colorless. The iodine value of "Alcon M-100" was determined in the same manner, except that "Alcon P-100" was replaced with "Alcon M-100." The iodine value of "Alcon P-100" was also measured in the same manner as the C9 petroleum resin of Example 1-3 [a mixture of C9 petroleum resin (A-1) and C9 petroleum resin (A-2)].

[0117] <Examples 1 to 3, Comparative Example 1> The components were added in the amounts shown in Table 1 and mixed by stirring to prepare curable compositions. The amount of each component shown in Table 1 is expressed in parts by mass.

[0118] (1) Storage stability The appearance of the prepared curable composition was visually inspected after standing for 24 hours in an environment of 25°C and 50% relative humidity. The results are shown in Table 1. a: Good b: Cloudy

[0119] (2) Moisture permeability evaluation (2-1) Preparation of moisture permeability samples The prepared curable composition was applied to a 60 μm thick polymethyl methacrylate film (PMMA) that had been subjected to corona treatment using an adhesive applicator. The moisture permeability of the 60 μm polymethyl methacrylate film at a temperature of 40° C. and a relative humidity of 90% was 70 [g / (m 2 ·24hr). An untreated polyethylene terephthalate film (trade name "Soft Shine" manufactured by Toyobo Co., Ltd.) was laminated on the coating layer of this curable composition and pasted using a nip roll (pressing pressure: 4.0 MPa). Then, the total integrated light amount (integrated amount of light irradiation intensity in the wavelength range of 320 to 400 nm) was measured at about 200 mJ / cm. 2 (Measuring instrument: FusionUV UV The coating layer of the curable composition was cured by irradiating it with ultraviolet (UVB) rays (measured with a Power Pack II) to obtain a laminate consisting of PMMA / cured layer of the curable composition (hereinafter also referred to as adhesive layer) / PET. The PET film was then peeled off and used as a sample for measuring moisture permeability. The thickness of the adhesive layer after curing 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.

[0120] (2-2) Moisture permeability measurement method The moisture permeability (g / (m) at a temperature of 40°C and a relative humidity of 90%) was measured using the cup method specified in JIS Z 0208. 2 The results are shown in Table 1.

[0121] (3) Adhesion evaluation (3-1) Preparation of samples for adhesion evaluation A polyvinyl alcohol-iodine polarizer (PVA) having a thickness of 25 μm and a cycloolefin film having a thickness of 50 μm were bonded together using an acrylic pressure-sensitive adhesive composition to prepare two polarizers with a protective film on one side. The curable adhesive composition was applied to one surface of one of the polarizers with a one-side protective film by using an adhesive applicator. The coating layer of the curable adhesive composition and the polarizer surface of the other polarizer with a one-side protective film were laminated using nip rolls. Then, the total integrated light amount (integrated amount of light irradiation intensity in the wavelength range of 320 to 400 nm) was adjusted to about 200 mJ / cm. 2 The adhesive layer was cured by irradiating it with ultraviolet light (UVB) (measured by a UV Power Puck II manufactured by FusionUV) to obtain a measurement sample having a layer structure of cycloolefin film / adhesive layer / polarizer / cured adhesive layer (cured film) / polarizer / adhesive layer / cycloolefin film. The thickness of the cured film of the curable adhesive composition was 10 μm.

[0122] (3-2) Tpeel peel test method The prepared sample was cut into a size of 200 mm long x 25 mm wide to serve as a test piece for measuring the peel strength between films. A cutter blade was inserted between the polarizers, and 30 mm of the polarizer was peeled off from the edge in the longitudinal direction. The peeled portion was then gripped with the gripping part of the testing machine. A peel test was performed on this test piece in accordance with JIS K 6854-3:1999 "Adhesives - Test Method for Peel Adhesion Strength - Part 3: T-Peel" at a gripping speed of 300 mm / min in an atmosphere of 23°C and 55% relative humidity. The average peel force (unit: N / 25 mm) over a 170 mm length excluding the 30 mm gripping part was determined and used as the peel strength between the PVA films. The measurement was performed 24 hours after the laminate was prepared. The results are shown in Table 1. In Table 1, "Material Failure" indicates that the peel strength was so great that the film broke before it could be peeled off during the test.

[0123] [Table 1] [Explanation of symbols]

[0124] 10 first thermoplastic resin film, 15 first adhesive layer, 20 second thermoplastic resin film, 25 second adhesive layer, 30 polarizer.

Claims

1. Contains a C9 petroleum resin (A) and a monofunctional (meth)acrylate compound (B), The C9 petroleum resin (A) is a curable composition containing two or more C9 petroleum resins having different bromine numbers, Further comprising a polyfunctional (meth)acrylate compound (C), a maleic anhydride-modified compound (D), and a photopolymerization initiator (E), The C9 petroleum resin (A) contains a C9 petroleum resin (A1) having a bromine number of less than 0.5 g / 100 g and a C9 petroleum resin (A2) having a bromine number of 0.7 g / 100 g or more in a mass ratio ((A1):(A2)) of 50 to 90:10 to 50, When the total amount of the curable composition is taken as 100% by mass, the content of the C9 petroleum resin (A) is 20% by mass or more and 70% by mass or less, the content of the monofunctional (meth)acrylate compound (B) is 9% by mass or more and 75% by mass or less, the content of the maleic anhydride-modified compound (D) is 3% by mass or more and 40% by mass or less, and the content of the photopolymerization initiator (E) is 0.1% by mass or more and 20% by mass or less, the curable composition is an adhesive for bonding a polyvinyl alcohol-based polarizer and a thermoplastic resin film, and the content of the monofunctional (meth)acrylate compound (B) is 60% by mass or more and 99% by mass or less when the total mass of the monofunctional (meth)acrylate compound (B) and the polyfunctional (meth)acrylate compound (C) is 100% by mass.

2. A polarizing plate comprising, in this order, a polyvinyl alcohol-based polarizer, an adhesive layer, and a thermoplastic resin film, wherein the adhesive layer is a cured layer of the curable composition described in claim 1.

3. 3. The polarizing plate according to claim 2, wherein the thermoplastic resin film is a (meth)acrylic resin film.

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

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