KR102627691B1 - Composition for forming easy adhesive layer - Google Patents

Abstract

[Problem] The object of the present invention is to provide a composition for forming an easily adhesive layer, which can form an easily adhesive layer on a substrate made of an acrylic resin having a ring structure.
[Solution] The composition for forming an easily adhesive layer for forming an easily adhesive layer on a substrate composed of an acrylic resin having a ring structure in the main chain includes a polyurethane resin (A) having a carboxyl group and an epoxy compound (B). has

Description

Composition for forming easy adhesive layer {Composition for forming easy adhesive layer}

The present invention provides a composition for forming an easily adhesive layer for forming an easily adhesive layer on a substrate made of an acrylic resin, an easily adhesive substrate comprising an easily adhesive layer formed from the composition on a substrate made of an acrylic resin, and the composition. It relates to a polarizing plate having a lamination unit in which a base material made of acrylic resin and a polarizer are laminated through an easily adhesive layer formed, and an image display device equipped with this polarizing plate.

Acrylic resins containing (meth)acrylic polymers, such as polymethyl methacrylate (PMMA), are excellent in optical properties such as light transmittance, and have an excellent balance of mechanical strength, moldability, and surface hardness. For this reason, acrylic resin is widely used as a transparent material in various industrial products, including automobiles and home appliances. Recently, the number of cases where acrylic resin is used for optics-related purposes is increasing, especially for optics included in image display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), and organic EL displays (OELDs). The application of acrylic resin to films is progressing. Among acrylic resins, in particular, acrylic resins having a ring structure are used in optical films from viewpoints of transparency, heat resistance, etc.

Optical films are sometimes used in a laminated state with other functional films. For example, a polarizer protective film, which is a type of optical film, is usually used in an image display device in the form of a polarizer and a laminated polarizing plate. A polarizing plate usually has a structure including a polarizer and a polarizer protective film bonded to at least one side of the polarizer through an adhesive.

When an acrylic resin is used in an optical film, an easily adhesive layer may be formed on the surface of the optical film in consideration of lamination with other functional films. The easily adhesive layer is a layer that improves the adhesiveness of the optical film and ensures lamination with other films through the adhesive layer. Patent Document 1 discloses a polarizing plate including a polarizer and a polarizer protective film bonded to at least one side of the polarizer through an adhesive. Furthermore, Patent Document 1 discloses a polarizing plate in which an easily adhesive layer containing a polyurethane resin and/or an amino group-containing polymer is formed on the surface of the polarizer protective film facing the polarizer.

However, in recent years, with the miniaturization and thinning of liquid crystal displays and the like, optical films are increasingly exposed to high-temperature and high-humidity environments. Patent Document 2 discloses a polarizing plate excellent in adhesion between a polarizer and a polarizer protective film in a high-temperature, high-humidity environment in which an easily adhesive layer is formed from an easily adhesive composition containing a urethane resin having a carboxyl group and a crosslinking agent. However, Patent Document 2 does not disclose a specific combination of a film formed of an acrylic resin having a ring structure and an easily adhesive layer formed of an easily adhesive composition containing an epoxy compound.

Patent Document 1: Japanese Patent Publication No. 2007-127893 Patent Document 2: Japanese Patent Publication No. 2009-193061

The purpose of the present invention is to provide a composition for forming an easily adhesive layer, which can form an easily adhesive layer (adhesive layer, adhesive layer) on a substrate (base film) made of an acrylic resin having a ring structure. Another object of the present invention is to provide a composition for forming an easily adhesive layer, which forms an easily adhesive layer with excellent adhesiveness (even under high temperature and high humidity) on a substrate made of an acrylic resin having a ring structure. there is. Another object of the present invention is to provide an easily adhesive substrate (adhesive film) in which an easily adhesive layer formed from the composition for forming an easily adhesive layer is formed on a substrate made of an acrylic resin having a ring structure. Another object of the present invention is to provide a polarizing plate (polarizing film) having a laminated unit in which a base material made of an acrylic resin having a ring structure and a polarizer are laminated through an easily adhesive layer formed from the composition for forming an easily adhesive layer. Another object of the present invention is to provide an image display device equipped with such a polarizing plate.

As a result of repeated research to solve the above problems, the present inventors have developed a polyurethane resin having a carboxyl group on a substrate composed of an acrylic resin having a ring structure in the main chain (or simply referred to as “acrylic resin substrate”). It was discovered that by forming an easily adhesive layer with a composition for forming an easily adhesive layer containing (A) and an epoxy compound (B), an easily adhesive base material excellent in adhesiveness even under high temperature and high humidity can be obtained.

That is, the present invention relates to the following composition for forming an easily adhesive layer, etc.

[1] A composition for forming an easily adhesive layer on a substrate composed of an acrylic resin having a ring structure in the main chain, and comprising a polyurethane resin (A) having a carboxyl group and an epoxy compound (B). .

[2] The composition according to [1] above, wherein the ring structure has at least one structure selected from maleic anhydride structure, maleimide structure, glutaric anhydride structure, glutarimide structure, lactam ring structure, and lactone ring structure. .

[3] The composition according to [1] or [2] above, wherein the epoxy compound (B) contains an aliphatic epoxy compound.

[4] The composition according to any one of [1] to [3] above, wherein the epoxy compound (B) satisfies the requirements of an epoxy equivalent of 200 g/equivalent or less and a viscosity of 2000 mPa·s or less.

[5] The composition according to any one of [1] to [4] above, wherein the epoxy compound (B) contains an aliphatic polyol polyglycidyl ether and satisfies the epoxy equivalent weight of 170 g/equivalent or less.

[6] The composition according to any one of [1] to [5] above, wherein the ratio of the polyurethane resin (A) and the epoxy compound (B) is former/latter (weight ratio) = 99/1 to 10/90.

[7] An easily adhesive substrate comprising a substrate composed of an acrylic resin having a ring structure in the main chain, and an easily adhesive layer formed on the substrate with the composition according to any one of [1] to [6] above.

[8] The easily adhesive substrate according to [7] above, wherein the thickness ratio of the substrate and the easily adhesive layer is former/latter = 1/0.1 to 1/0.001.

[9] The easily adhesive substrate according to [7] or [8] above for optical use.

[10] The easily adhesive substrate according to any one of [7] to [9] above for adhering to a polarizer.

[11] A polarizing plate having a laminated unit in which a base material composed of an acrylic resin having a ring structure in the main chain and a polarizer are laminated through an easily adhesive layer formed from the composition according to any one of [1] to [6] above.

[12] An image display device provided with the polarizing plate described in [11] above.

According to the present invention, a composition for forming an easily adhesive layer can be provided, which can form an easily adhesive layer on a substrate made of an acrylic resin having a ring structure. In addition, according to the present invention, it is possible to provide a composition for easily forming an adhesive layer, which easily forms an adhesive layer with excellent adhesiveness (even under high temperature and high humidity) on a substrate made of an acrylic resin having a ring structure. there is. Since this easily adhesive layer has excellent adhesiveness with other functional films, the adhesiveness with the polarizer is not impaired even under high temperature and high humidity. Furthermore, according to the present invention, an easily adhesive layer formed from such an easily adhesive layer forming composition can provide an easily adhesive substrate formed on a substrate composed of an acrylic resin having a ring structure. In addition, according to the present invention, a polarizing plate having a lamination unit in which a substrate made of an acrylic resin having a ring structure and a polarizer are laminated through an easily adhesive layer formed of the composition for forming an easily adhesive layer, and an image display device provided with such a polarizing plate are provided. can do.

Hereinafter, the present invention will be described in detail.

The composition for forming an easily adhesive layer of the present invention is a composition for forming an easily adhesive layer (adhesive layer, adhesive layer) on a substrate (base film) composed of an acrylic resin having a ring structure in the main chain. The composition for forming an easily adhesive layer of the present invention contains a polyurethane resin (A) having a carboxyl group and an epoxy compound (B).

[Polyurethane resin (A)]

Polyurethane resin (A) usually has a carboxyl group. In addition, the polyurethane resin (A) may contain one or two or more types of groups (for example, hydroxyl groups, amino groups, etc.) reactive with epoxy groups other than carboxyl groups.

The polyurethane resin (A) includes, for example, a structural unit derived from polyisocyanate compound (I) (or simply referred to as “polyisocyanate compound (I) unit”; hereinafter, the same expression applies) and polyol. (Ⅱ) A resin having a unit can be used. Furthermore, the polyurethane resin (A) may have units other than the polyisocyanate compound (I) unit and the polyol (II) unit (for example, carboxylic acid unit, amine unit, etc.). Examples of the polyurethane resin (A) include polyacrylic polyurethane resin, polyether polyurethane resin, and polyester polyurethane resin. Polyurethane resin may be used singly or in combination of two or more types.

The polyisocyanate compound (I) is not particularly limited as long as it has two or more isocyanate groups. Examples of the polyisocyanate compound (I) include polyisocyanate (e.g., aliphatic polyisocyanate, cycloaliphatic polyisocyanate, aromatic aliphatic polyisocyanate, aromatic polyisocyanate, etc.), modified form of polyisocyanate (or derivative, e.g. For example, multimers (dimers, trimers, etc.), carbodiimide products, biuret products, allophanate products, urethionic products, polyamine modified products, etc.]. The polyisocyanate compound (I) may be used individually or in combination of two or more types.

The aliphatic polyisocyanate is not particularly limited, but includes, for example, aliphatic diisocyanate [for example, alkane diisocyanate (for example, tetramethylene diisocyanate, hexamethylene diisocyanate, 2, 2, 4-trimethylhexamethylene diisocyanate) C _2-20 alkane diisocyanates such as isocyanate, dodecamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1, 5-diisocyanate, 3-methylpentane-1, 5-diisocyanate, preferably C _{4 -12} alkane diisocyanate, etc.)], aliphatic polyisocyanates having 3 or more isocyanate groups (for example, aliphatic tri to hexaisocyanates such as 1, 4, 8-triisocyanatooctane, etc.).

The alicyclic polyisocyanate is not particularly limited, but includes, for example, alicyclic diisocyanate (e.g., cycloalkane diisocyanate (e.g., methyl-2, 4- or 2, 6-cyclohexane diisocyanate, etc.) C _5-8 cycloalkane diisocyanate, etc.), isocyanato alkyl cycloalkane isocyanate [e.g., 3-isocyanatomethyl-3, 5, 5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), etc. Isocyanato C _1-6 alkyl C _5-10 cycloalkane isocyanate, etc.], di(isocyanatoalkyl) cycloalkane [e.g., di(isocyanato C _1-6 alkyl) such as hydrogenated xylene diisocyanate. C _5-10 cycloalkane], di(isocyanato cycloalkyl)alkane [for example, bis such as hydrogenated diphenylmethane-4, 4'-diisocyanate (4, 4'-methylenebis cyclohexyl isocyanate) (isocyanato C _5-10 cycloalkyl) C _1-10 alkane, etc.], polycycloalkane diisocyanate (norbornene diisocyanate, etc.)}, alicyclic polyisocyanate having 3 or more isocyanate groups (e.g., and alicyclic tri- to hexa-isocyanates such as 1, 3, 5-triisocyanatocyclohexane).

The araliphatic polyisocyanate is not particularly limited, but includes, for example, araliphatic diisocyanate (for example, di(isocyanatoalkyl)arene [for example, xylene diisocyanate (XDI), tetramethyl xylene diisocyanate ( TMXDI) (1, 3- or 1, 4-bis (1-isocyanato-1-methylethyl) benzene), etc., bis (isocyanato C _1-6 alkyl) C _6-12 arene, etc.]}, 3 and araliphatic polyisocyanates having two or more isocyanate groups (for example, araliphatic tri- to hexa-isocyanate, etc.).

The aromatic polyisocyanate is not particularly limited, but includes, for example, aromatic diisocyanate {for example, arene diisocyanate [for example, o-, m- or p-phenylene diisocyanate, chlorophenylene diisocyanate, toluene diisocyanate, C _6-12 arene diisocyanate such as naphthalene diisocyanate (NDI), etc.], di(isocyanatoaryl)alkane [e.g., diphenylmethane diisocyanate (MDI) (2, 4'-diphenyl methane diisocyanate, 4, 4'-diphenylmethane diisocyanate, etc.), tolidine diisocyanate, etc., bis(isocyanato C _6-10 aryl) C _1-10 alkane, etc.], aromatic poly having 3 or more isocyanate groups Isocyanates (for example, aromatic tri- to hexa-isocyanates such as 4, 4'-diphenylmethane-2, 2', 5, 5'-tetriisocyanate, etc.) can be mentioned.

Among the polyisocyanate compounds (I), diisocyanate compounds (for example, aliphatic diisocyanate, cycloaliphatic diisocyanate, araliphatic diisocyanate, aromatic diisocyanate, etc.) are often used.

Polyol (II) is not particularly limited as long as it has two or more hydroxy groups. Examples of polyol (II) include polyacrylic polyol, polyester polyol, polyether polyol, and polyurethane polyol. Polyol (II) may be used individually or in combination of two or more types.

Examples of polyacrylic polyol include a copolymer having a (meth)acrylic acid ester unit and a unit derived from a component having a hydroxy group (component unit having a hydroxy group). Polyacrylic polyol may have units other than the (meth)acrylic acid ester unit and the component unit having a hydroxy group.

There is no particular limitation on the (meth)acrylic acid ester, and examples include aliphatic (meth)acrylates [e.g., (meth)acrylic acid alkyl esters (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid C _1-18 alkyl, such as butyl (meth)acrylate), etc.], alicyclic (meth)acrylates [e.g., (meth)acrylic acid cycloalkyl ester (e.g., (meth)acrylic acid cyclopropyl), etc. , C _3-20 cycloalkyl acrylic acid such as cyclobutyl (meth)acrylate), cross-linked (meth)acrylate (e.g. isobornyl (meth)acrylate), etc.], aromatic (meth)acrylate [e.g. , (meth)acrylic acid aryl ester (e.g., (meth)acrylic acid C _6-20 aryl such as phenyl (meth)acrylate, (meth)acrylic acid o-tryl), (meth)acrylic acid aralkyl ester (e.g., (meth)acrylic acid C _6-10 aryl C _1-4 alkyl such as benzyl (meth)acrylate), phenoxyalkyl (meth)acrylic acid (for example, (meth)acrylic acid phenoxy such as phenoxyethyl (meth)acrylate) C _1-4 alkyl), etc.] and the like. These may be used individually or in combination of two or more types.

The component (monomer) having a hydroxy group is not particularly limited, and examples include (meth)acrylic acid hydroxyalkyl esters [e.g., (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxy (meth)acrylic acid hydroxy C, such as propyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl, (meth)acrylic acid 4-hydroxybutyl, (meth)acrylic acid 2-hydroxypentyl, etc. _1-18 alkyl, etc.], (meth)acrylic acid monoester of polyhydric alcohol (e.g., glycerin, trimethylolpropane, etc.), etc. These may be used individually or in combination of two or more types.

Examples of polyester polyol include copolymers having a polyhydric carboxylic acid component unit and a polyol component unit. Polyester polyol may have units other than the polyhydric carboxylic acid component unit and the polyol component unit.

The polyhydric carboxylic acid component is not particularly limited, but includes, for example, dicarboxylic acids (e.g., aromatic dicarboxylic acids (e.g., C _6-12 arenedicarboxylic acids such as orthophthalic acid, isophthalic acid, terephthalic acid, etc.), alicyclic acids, etc. Dicarboxylic acids (e.g., C _5-10 cycloalkanedicarboxylic acids such as hexahydrophthalic acid, tetrahydrophthalic acid, 1, 3-cyclohexanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid), aliphatic dicarboxylic acids (e.g. For example, C _2-20 alkanes such as oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, and octadecanedicarboxylic acid. acids)], acid anhydrides of these dicarboxylic acids, lower alcohol esters of these dicarboxylic acids, etc. These may be used individually or in combination of two or more types.

The polyol component is not particularly limited, but includes, for example, dihydric alcohols (e.g., aliphatic diols [e.g., alkanediols (e.g., ethylene glycol, 1,2-propanediol, 1,3-propanediol) , 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1,6 _- hexanediol, 1,8-octanediol, 1,10-decanediol, etc.) , polyalkylene glycol (e.g., C _2-12 alkylene glycol such as diethylene glycol, triethylene glycol, dipropylene glycol, etc.), alicyclic diol [e.g., cycloalkanediol (e.g., 1, C _5-10 cycloalkanediols such as 4-cyclohexanediol, etc.), hydrogenated bisphenols (e.g., hydrogenated bisphenol A, hydrogenated bisphenol F, etc.)], aromatic diols [e.g., dihydroxyarenes ( For example, dihydroxy C _6-12 arenes such as o-, m- or p-dihydroxybenzene, etc.), bisphenol (for example, bisphenol A, bisphenol F, etc.)]}, etc. These may be used individually or in combination of two or more types.

Examples of polyether polyol include copolymers obtained by adding alkylene oxide to polyhydric alcohol. The polyhydric alcohol is not particularly limited, and for example, the dihydric alcohols mentioned above can be used. Polyhydric alcohols may be used individually or in combination of two or more types. Moreover, the alkylene oxide is not particularly limited, and examples include C _2-12 alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide. Alkylene oxide may be used individually or in combination of two or more types.

Examples of polyurethane polyol include copolymers having a polyisocyanate compound unit and a polyol component unit. Polyurethane polyol may have units other than the polyisocyanate compound unit and the polyol component unit.

In polyurethane polyol, the polyisocyanate compound from which the polyisocyanate compound unit is derived is not particularly limited, and for example, polyisocyanate compound (I) that can be used in polyurethane resin (A) may be used. . The polyisocyanate compound may be used individually or in combination of two or more types.

In polyurethane polyol, the polyol component from which the polyol component unit is derived is not particularly limited, but examples include polyol (II) (e.g., polyacrylic polyol, It is okay to use polyester polyol, polyether polyol, etc.). The polyol component may be used individually or in combination of two or more types.

The polyurethane resin (A) may contain a chain extender as a constituent (or may have a structural unit derived from the chain extender). The chain extender is not particularly limited, and examples include glycols (e.g., C _2-6 alkane diols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol); Polyhydric alcohols (e.g., C _2-6 alkane tri to hexaol such as glycerin, trimethylolpropane, and pentaerythritol) and diamines (e.g., ethylenediamine, hexamethylenediamine, etc.) are common chain extensions. It's okay to use it. Additionally, in addition to general chain extenders, chain extenders having a carboxyl group described later may be used.

In the polyurethane resin (A), the form in which the carboxyl group is contained is not particularly limited, and the carboxyl group may be contained in units derived from monomers such as polyisocyanate compound (I) units and polyol (II) units. In addition, in the polyurethane resin (A), the carboxyl group may be contained in a unit derived from the chain extender.

The method for producing the polyurethane resin (A) is not particularly limited as long as it involves reacting the polyisocyanate compound (I) with the polyol (II). Additionally, in the production of polyurethane resin (A), a chain extender may be used. When introducing a carboxyl group into the polyurethane resin (A) by a chain extender, examples of the chain extender include dihydroxycarboxylic acid [e.g., dimethylolalkanoic acid (e.g., dimethylolacetic acid, dimethyl It is also acceptable to use a chain extender having a carboxyl group such as dimethylol C _2-10 alkane carboxylic acid, preferably C _2-8 alkane carboxylic acid, such as olbutanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, and dimethylolpentanoic acid.

The number average molecular weight of the polyurethane resin (A) is not particularly limited, but may be, for example, 050,000 to 1 million, preferably 050,000 to 600,000, and more preferably 10,000 to 400,000. Furthermore, the number average molecular weight may be a value determined by polystyrene conversion using gel permeation chromatography. In addition, the acid value of the polyurethane resin (A) is not particularly limited, but may be, for example, 10 mgKOH/g or more, preferably 10 to 50 mgKOH/g, and more preferably 20 to 45 mgKOH/g.

[Epoxy compound (B)]

The epoxy compound (B) usually contains a compound having 2 or more (for example, 2 to 6, preferably 2 to 4, more preferably 2 to 3) epoxy groups.

The compound having two or more epoxy groups is not particularly limited, and examples include aliphatic epoxy compounds, cycloaliphatic epoxy compounds, and aromatic epoxy compounds.

Examples of the aliphatic epoxy compound include aliphatic polyol polyglycidyl ether [e.g., chain-shaped aliphatic polyol polyglycidyl ether (e.g. alkane polyol polyglycidyl ether, polyalkane polyol polyglycidyl ether, etc.)] and the like.

Examples of the alkane polyol polyglycidyl ether include alkanediol polyglycidyl ether [e.g., alkylene glycol diglycidyl ether (e.g., ethylene glycol diglycidyl ether, propylene glycol digly ether) C _2-10 alkanediol diglycidyl ethers such as cidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether), alkane tri to hexaol polyglycidyl ether { For example, glycerin polyglycidyl ether (e.g., glycerin di- or triglycidyl ether, etc.), pentaerythritol polyglycidyl ether, sorbitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, etc. C _2-10 alkane tri to hexaol polyglycidyl ether }] and the like.

Examples of the polyalkane polyol polyglycidyl ether include polyalkanediol polyglycidyl ether [e.g., polyalkylene glycol diglycidyl ether {e.g., polyethylene glycol diglycidyl ether (e.g. For example, diethylene glycol diglycidyl ether, etc.), poly C _2-4 alkylene glycol diglycidyl ether, such as polypropylene glycol diglycidyl ether, etc.}], polyalkane tri to tetraol polyglycidyl C _6-12 polyalkanes such as diglycerin polyglycidyl ether (e.g., diglycerin di- or triglycidyl ether), dipentaerythritol polyglycidyl ether, tri-tetra, etc. all-polyglycidyl ether, etc.} and the like. Moreover, in the polyalkane polyol polyglycidyl ether, the number of alkane polyols is not particularly limited, for example, 2 to 15, preferably 2 to 12, more preferably 2 to 10. It's okay if you do it. When the number of alkane polyols is not too large (for example, 15 or less), it is preferable because the adhesiveness of the easily adhesive layer is excellent.

Examples of the alicyclic epoxy compound include polyglycidyl ethers of polyhydric alcohols having at least one alicyclic ring [e.g., cycloalkane polyol polyglycidyl ethers (e.g., C _5-8 cycloalkane) C _5-8 cycloalkane polyol polyglycidyl ethers such as diol diglycidyl ether), polyglycidyls of hydrogenated bisphenols (e.g. hydrogenated bisphenols such as hydrogenated bisphenol A, hydrogenated bisphenol F, etc.) cidyl ether, etc.].

Examples of aromatic epoxy compounds include polyglycidyl ethers of polyhydric phenols having at least one aromatic ring (e.g., polyglycidyl ethers of bisphenols (e.g., bisphenols such as bisphenol A and bisphenol F) dil ether, novolac type epoxy resin, etc.].

Furthermore, as described above, the epoxy compound (B) usually contains a compound having two or more epoxy groups, but may also contain a compound having one epoxy group.

Additionally, the number of epoxy groups in the epoxy compound (B) is usually 2 or more on average (for example, 2 to 6, preferably 2 to 4, more preferably 2 to 3). When the number of epoxy groups is too large (for example, 6 or less), the crosslinking reaction proceeds sufficiently and the adhesiveness of the easily adhesive layer is excellent, so it is preferable.

The epoxy compound (B) can be used individually or in combination of two or more types. The epoxy compound (B) preferably contains an aliphatic epoxy compound, and more preferably contains an aliphatic polyol polyglycidyl ether, alkane di to hexaol polyglycidyl ether, poly alkane di to tetraol poly It is more preferable that it contains glycidyl ether.

The epoxy equivalent of the epoxy compound (B) is not particularly limited, but in the present invention, it is particularly, for example, 200 g/equivalent or less (e.g., 100 to 180 g/equivalent), preferably 170 g/equivalent or less (e.g. , 110 to 160 g/equivalent), more preferably 150 g/equivalent or less (e.g., 120 to 150 g/equivalent). When the epoxy equivalent weight is not too large (for example, 200 g/equivalent or less), the crosslinking reaction proceeds sufficiently and the adhesiveness of the easily adhesive layer is excellent, so it is preferable.

The viscosity of the epoxy compound (B) is not particularly limited, but is, for example, 2000 mPa·s or less (e.g., 0.1 to 1,800 mPa·s), preferably 1,500 mPa·s or less (e.g., 1 to 1,300 mPa·s) ), more preferably a relatively low viscosity of about 1000 mPa·s or less (for example, 5 to 800 mPa·s). When the viscosity is not too high (for example, 2000 mPa·s or less), it is preferable because the crosslinking reaction proceeds sufficiently and the adhesiveness of the easily adhesive layer is excellent.

The number of atoms in the longest atomic chain of the epoxy compound (B) is, for example, 3 to 15 (e.g., 4 to 14), preferably 5 to 13 (e.g., 6 to 12), more preferably A score of 7 to 11 (e.g., 8 to 10) is okay. By setting it within the above range, the crosslinking density can be increased and the adhesiveness of the easily adhesive layer can be improved. Here, the longest atomic chain of the epoxy compound (B) refers to the longest atomic chain among the total number of atoms (e.g., carbon atoms, oxygen atoms, etc.) constituting the chain-like structure connecting two epoxy groups, and the longest The total number of atoms that make up an atomic chain is called the number of atoms in the longest atomic chain.

[Composition for easy adhesive layer formation]

The composition for forming an easily adhesive layer may contain a polyurethane resin (A) and an epoxy compound (B), and may also contain one or more types of other components (for example, additives, etc.). The additive is not particularly limited, and examples include anti-blocking agents, dispersion stabilizers, thixotropic agents, antioxidants, ultraviolet absorbers, anti-foaming agents, thickeners, dispersants, surfactants, catalysts, lubricants, antistatic agents, etc. Among additives, it is preferable to include an anti-blocking agent. As an anti-blocking agent, for example, silica fine particles may be used.

The particle diameter (average primary particle diameter) of the anti-blocking agent may be, for example, about 1 to 500 nm from the viewpoint of improving adhesion. The anti-blocking agent preferably contains particles with a relatively small particle diameter of about 1 to 250 nm, preferably 3 to 200 nm, and more preferably about 5 to 150 nm. The anti-blocking agent may contain particles with at least a relatively small particle diameter, and may also contain particles with a relatively large particle diameter (for example, about 250 to 500 nm). The average primary particle diameter of the anti-blocking agent can be determined using a laser diffraction/scattering type particle size distribution measuring device (e.g., Submicron Particle Sizer NICOMP380, manufactured by Particle Sizing Systems).

When the anti-blocking agent contains particles with a relatively small particle diameter (e.g., 1 to 250 nm) and particles with a relatively large particle diameter (e.g., 250 to 500 nm), from the viewpoint of improved adhesion and blocking resistance, etc. , the former/latter (weight ratio) may be, for example, 1/1 to 500/1, preferably 2/1 to 300/1, and more preferably 3/1 to 100/1.

In the composition for forming an easily adhesive layer, the content ratio of the polyurethane resin (A) is not particularly limited, but is, for example, 1 to 20% by weight, preferably 1.5 to 15% by weight, more preferably 2 to 12% by weight. Even if it is around %, it is okay.

In the composition for forming an easily adhesive layer, the content ratio of the epoxy compound (B) is not particularly limited, but is, for example, 1 to 10% by weight, preferably 0.2 to 8% by weight, more preferably 0.3 to 6% by weight. It's okay to be okay.

In addition, in the composition for forming an easily adhesive layer, the ratio of the polyurethane resin (A) and the epoxy compound (B) is not particularly limited, but the former/latter (weight ratio) is, for example, 99/1 to 10/90, Preferably it is 95/5 to 30/70, more preferably 90/10 to 50/50. By setting it within the above range, the crosslinking reaction can sufficiently proceed and the adhesiveness of the easily adhesive layer can be improved.

In the composition for forming an easily adhesive layer, the content ratio of the additive is not particularly limited, but is, for example, 0.1 to 30 parts by weight relative to 100 parts by weight of the total amount of the polyurethane resin (A) and the epoxy compound (B). For example, 1 to 25 parts by weight), preferably 1 to 20 parts by weight (for example, 5 to 15 parts by weight).

In particular, in the composition for forming an easily adhesive layer, the content ratio of the anti-blocking agent is not particularly limited, but is, for example, 0.1 to 30 parts by weight with respect to 100 parts by weight of the total amount of the polyurethane resin (A) and the epoxy compound (B). (For example, 1 to 25 parts by weight), preferably 1 to 20 parts by weight (for example, 5 to 15 parts by weight). In addition, in the composition for forming an easily adhesive layer, the content of the anti-blocking agent is, for example, 1 to 50% by weight, preferably 2 to 40% by weight, more preferably from the viewpoint of improving adhesion and blocking resistance, etc. It is okay to have about 3 to 30% by weight. In particular, when it contains particles with a relatively large diameter (for example, 250 to 500 nm), it is okay to contain about 0.1 to 1% by weight of particles of the large size.

The form of use of the composition for forming an easily adhesive layer is not particularly limited, but for example, water-based (e.g., water-dispersed type (emulsion, etc.), water-soluble type, etc.), solvent-based, etc. are acceptable, and water-based is preferred. In the case of an aqueous system, compared to a solvent system, the environmental load generated when forming an adhesive layer is small and workability is excellent.

The solvent is not particularly limited, but includes, for example, aromatic hydrocarbons (e.g. toluene, xylene, etc.), ketones (e.g. acetone, methyl ethyl ketone, methyl isobutyl ketone), esters (e.g. , ethyl acetate, butyl acetate, etc.), alcohols (for example, n-butyl alcohol, isopropyl alcohol, etc.).

Moreover, even when the composition for forming an easily adhesive layer is used in an aqueous form, a solvent (e.g., ketones, alcohols, etc.) may be used in addition to water.

When the composition for forming an easily adhesive layer is water-based or solvent-based, the solid content concentration in the liquid may be, for example, 1 to 50% by mass, preferably about 5 to 30% by mass.

[Acrylic resin]

The acrylic resin is not particularly limited as long as it has a ring structure in the main chain. Acrylic resin usually has a (meth)acrylic acid ester unit.

The (meth)acrylic acid ester unit is not particularly limited, but examples include aliphatic (meth)acrylates [e.g., (meth)acrylic acid alkyl esters (e.g., methyl (meth)acrylate, ethyl (meth)acrylate) , (meth)acrylic acid C _1-18 alkyl such as butyl (meth)acrylate, etc.], alicyclic (meth)acrylate [e.g., (meth)acrylic acid cycloalkyl ester (e.g., (meth)acrylic acid cycloalkyl ester), etc. C _3-20 cycloalkyl (meth)acrylate such as propyl, cyclobutyl (meth)acrylate), cross-linked (meth)acrylate (e.g. isobornyl (meth)acrylate), etc.], aromatic (meth)acrylic Rates [e.g., (meth)acrylic acid aryl esters (e.g., (meth)acrylic acid C _6-20 aryl such as (meth)acrylic acid phenyl, (meth)acrylic acid o-tryl), (meth)acrylic acid aralkyl ester (For example, C _6-10 aryl C _1-4 alkyl (meth)acrylate, such as benzyl (meth)acrylate), phenoxyalkyl (meth)acrylate (for example, phenoxyethyl (meth)acrylate, etc. Units derived from (meth)acrylic acid esters such as (meth)acrylic acid phenoxy C _1-4 alkyl) and the like can be mentioned. These may have one type or two or more types.

Among the (meth)acrylic acid ester units, from the viewpoint of improving transparency, etc., those containing at least an alkyl methacrylate unit are preferable, and those containing at least a methacrylic acid C _1-18 alkyl unit are more preferable, and It is more preferable that it contains at least a methyl acrylate unit.

The content ratio of the methacrylic acid alkyl ester unit in the (meth)acrylic acid ester unit is, for example, 50 to 95% by mass, preferably 70 to 90% by mass. In addition, the content ratio of the methacrylic acid alkyl ester unit in the (meth)acrylic acid ester unit is, for example, 50 to 95 mol%, preferably 70 to 90 mol%, in terms of monomers constituting the (meth)acrylic acid ester unit. am.

Ring structures include, for example, cyclic imide structures (e.g., maleimide structure, glutarimide structure, etc.) and cyclic anhydride structures (e.g., maleic anhydride structure, glutaric acid anhydride structure, etc.). , lactam structure, lactone ring structure, etc. The ring structure is at least one selected from the group consisting of maleic anhydride structure, (N-substituted) maleimide structure, glutaric anhydride structure, glutarimide structure, lactam structure, and lactone ring structure, from the viewpoint of heat resistance, optical properties, etc. It is desirable to have a structure. The acrylic resin may have one or two or more types of these ring structures.

The glutarimide structure and the glutaric anhydride structure are, for example, the structures represented by the following formula (1).

[Formula 1]

(In the formula, R ¹ and R ² are each independently a hydrogen atom or an alkyl group, R ³ is a hydrogen atom or a substituent, and X ¹ is an oxygen atom or a nitrogen atom. When X ¹ is an oxygen atom, n=0 , and when X ¹ is a nitrogen atom, n = 1.)

In R ¹ and R ² in formula (1), examples of the alkyl group include C _1-8 alkyl group (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group) group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, isohexyl group, n-heptyl group, isoheptyl group, n-octyl group, 2-ethylhexyl group, etc.). However, the present invention is not limited to the related examples. Among R ¹ and R ² , a hydrogen atom or a C _1-4 alkyl group is preferable from the viewpoint of obtaining a film with excellent heat resistance and low birefringence.

In R ³ in formula (1), examples of the substituent include a hydrocarbon group. Examples of the hydrocarbon group include an aliphatic group, an alicyclic group, and an aromatic group. Furthermore, the hydrocarbon group may further have a substituent such as halogen.

In R ³ in formula (1), examples of the aliphatic group include C _1-10 alkyl groups (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, isohexyl group, n-heptyl group, isoheptyl group, n-octyl group, 2-ethylhexyl group, etc.), etc. The present invention is not limited to the relevant examples. Among these alkyl groups, a C _1-4 alkyl group is preferable and a methyl group is more preferable from the viewpoint of obtaining a film with excellent heat resistance and low birefringence.

In R ³ of the formula (1), examples of the alicyclic group include a C _3-12 cycloalkyl group (e.g., cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, etc.). , the present invention is not limited to the related examples. Among these cycloalkyl groups, a C _3-7 cycloalkyl group is preferable, and a cyclohexyl group is more preferable from the viewpoint of obtaining an acrylic resin with excellent heat resistance and low birefringence.

In R ³ of the formula (1), examples of the aromatic group include, for example, a C _6-20 aromatic group [e.g., a C _6-20 aryl group (e.g., phenyl group, o-toryl group, m-to Ryl group, p-toryl group, 2, 3-xylyl group, 2, 4-xylyl group, 2, 5-xylyl group, 2, 6-xylyl group, 3, 4-xylyl group, 3, 5 -xylyl group, 1-naphthyl group, 2-naphthyl group, binaphthyl group, anthryl group, etc.), C _7-20 aralkyl group (e.g., benzyl group, etc.), etc.], but the present invention , it is not limited to related examples. Among these aromatic groups, phenyl group and toryl group are preferable from the viewpoint of obtaining a film with excellent heat resistance and low birefringence.

In the structure shown in formula (1), from the viewpoint of excellent heat resistance, etc., preferably, R ¹ and R ² are each independently a hydrogen atom or a methyl group, and R ³ is a C _1-10 alkyl group, C _3-12 It is a cycloalkyl group or a C _6-20 aromatic group, and more preferably, R ¹ and R ² are each independently a hydrogen atom or a methyl group, and R ³ is a C _1-4 alkyl group, a C _3-7 cycloalkyl group, or a C _{6 -20} aryl group or C _7-20 aralkyl group, more preferably, R ¹ and R ² are each independently a hydrogen atom or a methyl group, R ³ is a methyl group, cyclohexyl group, phenyl group or toryl group, and most preferably Preferably, R ¹ and R ² are each independently a hydrogen atom or a methyl group, and R ³ is a cyclohexyl group or a phenyl group.

The maleic anhydride structure and the maleimide structure are, for example, the structures shown in the following chemical formula (2).

[Formula 2]

(In the formula, R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, R ⁶ is a hydrogen atom or a substituent, and X ² is an oxygen atom or a nitrogen atom. When X ² is an oxygen atom, n = 0; When X ² is a nitrogen atom, n=1.)

In R ⁶ of the formula (2), examples of the substituent include a hydrocarbon group. Examples of the hydrocarbon group include aliphatic groups (e.g., alkyl groups [e.g., C _1-6 straight chain alkyl groups (e.g., methyl groups, ethyl groups, etc.), C _1-6 branched alkyl groups (e.g., C _1-6 alkyl group such as isopropyl group, etc.], etc.), alicyclic group (e.g. C _3-20 cycloalkyl group such as cyclopentyl group, cyclohexyl group, etc.), aromatic group {e.g. C _6-20 aromatic group [eg, C _7-20 aralkyl group (eg, benzyl group, etc.), C _6-20 aryl group (eg, phenyl group, etc.)]. Furthermore, the hydrocarbon group may further have a substituent such as halogen.

When X ² is an oxygen atom, the ring structure shown by Chemical Formula (2) becomes a maleic anhydride structure. The maleic anhydride structure can be formed, for example, by copolymerizing maleic anhydride and (meth)acrylic acid ester.

When X ² is a nitrogen atom, the ring structure shown by Chemical Formula (2) becomes a maleimide structure. The maleimide structure can be formed, for example, by copolymerizing maleimide and (meth)acrylic acid ester.

^{When _ _ _} _{_ _} , more preferably, R ⁴ and R ⁵ are each independently a hydrogen atom, and R ⁶ is a cyclohexyl group or a phenyl group.

The lactone ring structure is not particularly limited and may be, for example, a 4-membered ring to an 8-membered ring, but a 5-membered ring or a 6-membered ring is preferable because the stability of the ring structure is excellent, and a 6-membered ring is more preferable.

The lactone ring structure, which is a 6-membered ring, is, for example, the structure disclosed in Japanese Patent Application Laid-Open No. 2004-168882. However, due to the high polymerization yield of the precursor and the cyclization condensation reaction of the precursor, acrylics have a high lactone ring content. For reasons such as the ability to obtain a resin, the structure shown in the following formula (3) is preferable.

[Formula 3]

(In the formula, R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom or a substituent.)

In the formula (3), examples of the substituent include organic residues such as hydrocarbon groups. Examples of the hydrocarbon group include aliphatic groups (e.g., C _1-20 alkyl groups such as methyl, ethyl, and propyl groups, C _2-20 unsaturated aliphatic hydrocarbon groups such as ethenyl and propenyl groups, etc.), aromatic groups, etc. (For example, C _6-20 aromatic hydrocarbon groups such as phenyl group, naphthyl group, etc.). The hydrocarbon group may contain an oxygen atom, and one or more of the hydrogen atoms may be substituted by at least one type of group selected from a hydroxyl group, a carboxyl group, an ether group, and an ester group.

In the formula (3), from the viewpoint of excellent heat resistance, etc., R ⁹ is preferably a hydrogen atom or a methyl group, R ⁷ and R ⁸ are each independently a hydrogen atom or a C _1-20 alkyl group, and more preferably R ⁹ is a hydrogen atom or a methyl group, and R ⁷ and R ⁸ are each independently a hydrogen atom or a methyl group.

The lactam ring structure is not particularly limited, and for example, it is the pyrrolidinone ring structure shown in the following formula (4). The pyrrolidinone ring structure has a 5-membered amide ring structure (cyclic amide structure) as the basic skeleton. This cyclic amide structure is also a 5-membered ring lactam structure (γ-lactam structure). Having a pyrrolidinone ring structure in the main chain means that at least one atom out of the five atoms constituting the basic skeleton of the five-membered pyrrolidinone ring structure, typically an amide bond (-N(R) CO-) This means that the three carbon atoms that do not constitute are located in the main chain of the polymer and constitute the main chain.

[Formula 4]

(In the formula, R ¹⁰ to R ¹² are each independently a hydrogen atom or a substituent.)

For R ¹⁰ in the formula (4), examples of the substituent include a hydrocarbon group or -NHCOR ¹³ group (R ¹³ is a hydrogen atom or a hydrocarbon group).

Examples of the hydrocarbon group for R ¹⁰ or R ¹³ include an aliphatic group, an alicyclic group, or an aromatic group. Examples of aliphatic groups include C _1-18 alkyl groups (e.g., C _1-18 straight chain or molecular alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, etc.) ), etc. Examples of the alicyclic group include a C _3-18 cycloalkyl group (eg, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, etc.). Examples of aromatic groups include C _6-20 aromatic groups [e.g., C _6-20 aryl groups (e.g., phenyl group, toryl group, xylyl group, naphthyl group, anthryl group, etc.), C _{7 -20} aralkyl group (for example, benzyl group, etc.), etc.] can be mentioned.

As R ¹⁰ , a hydrogen atom, a C _1-18 linear alkyl group (for example, a methyl group, etc.), etc. are particularly preferable. In addition, R ¹³ is, in particular, a hydrogen atom, a C _1-18 linear alkyl group (preferably a C _1-12 linear alkyl group, more preferably a C _1-4 linear alkyl group, etc.), a C _6-20 aryl group ( For example, a phenyl group, etc.), a C _3-18 cycloalkyl group (preferably a C _3-12 cycloalkyl group, more preferably a C _3-6 cycloalkyl group, etc.) are preferable.

For R ¹¹ in the formula (4), examples of the substituent include -COOR ¹⁴ group (R ¹⁴ is a hydrogen atom or a hydrocarbon group).

Examples of the hydrocarbon group for R ¹⁴ include the hydrocarbon groups exemplified for R ¹⁰ or R ¹³ . Additionally, the particularly preferred embodiment of R ¹⁴ is the same as the particularly preferred embodiment of R ¹³ .

For R ¹² in the formula (4), examples of the substituent include -COR ¹⁵ group (R ¹⁵ is a hydrogen atom or a hydrocarbon group).

Examples of the hydrocarbon group for R ¹⁵ include hydrocarbon groups exemplified by R ¹⁰ or R ¹³ . Additionally, the particularly preferred embodiment of R ¹⁵ is the same as the particularly preferred embodiment of R ¹³ .

The ring structure content in the acrylic resin is, for example, 1 to 60 mol%, preferably 1 to 40 mol%, and more preferably 2 to 30 mol%. Additionally, the ring structure content in the acrylic resin is, for example, 1 to 80 mass%, preferably 1 to 50 mass%, and more preferably 2 to 40 mass%. In this case, acrylic resin is preferable because it can achieve both excellent transparency, heat resistance, and strength.

In particular, the content of the glutarimide structure and/or glutaric anhydride structure in the acrylic resin is preferably 5% by mass or more, more preferably 10% by mass, from the viewpoint of improving the heat resistance and transparency of the acrylic resin. It is % by mass or more, more preferably 15 mass % or more, and from the viewpoint of improving formability into a film and increasing mechanical strength, for example, 90 mass % or less, preferably 60 mass % or less, more preferably Preferably it is 57 mass% or less, more preferably 55 mass% or less. Furthermore, the content of the glutarimide structure and/or glutaric anhydride structure in the acrylic resin is, for example, 3 to 85 mol%, preferably 6, from the viewpoint of improving the heat resistance and transparency of the acrylic resin. ~50 mol%, more preferably 10 to 40 mol%.

In addition, the content of maleic anhydride structure and/or (N-substituted) maleimide structure in the acrylic resin is preferably, for example, 5 to 90% by mass from the viewpoint of improving the heat resistance and transparency of the acrylic resin. It is preferably 10 to 70 mass%, more preferably 10 to 60 mass%, and even more preferably 10 to 50 mass%. Furthermore, the content of the maleic anhydride structure and/or maleimide structure in the acrylic resin is, for example, 7 to 90 mol%, preferably 10 to 75 mol%, from the viewpoint of improving the heat resistance and transparency of the acrylic resin. Mol%, more preferably 10 to 60 mol%.

In addition, the content of the lactone structure in the acrylic resin is not particularly limited, but from the viewpoint of improving the heat resistance and transparency of the acrylic resin, for example, 10 to 70% by mass, preferably 15 to 50% by mass. , more preferably 15 to 45 mass%. Furthermore, the content of the lactone structure in the acrylic resin is, for example, 6 to 60 mol%, preferably 9 to 37 mol%, more preferably 9 mol%, from the viewpoint of improving the heat resistance and transparency of the acrylic resin. It is ~30 mol%.

In addition, the content of the lactam ring structure in the acrylic resin is not particularly limited, but from the viewpoint of improving the heat resistance and transparency of the acrylic resin, for example, 10 to 70% by mass, preferably 15 to 50% by mass. %, more preferably 15 to 45 mass %. Furthermore, the content of the lactam ring structure in the acrylic resin is, for example, 6 to 60 mol%, preferably 9 to 37 mol%, more preferably, from the viewpoint of improving the heat resistance and transparency of the acrylic resin. It is 9 to 30 mol%.

The weight average molecular weight (Mw) of the acrylic resin in terms of styrene according to the GPC measurement method is not particularly limited, but is preferably 10,000 to 500,000, more preferably 30,000 to 300,000, and even more preferably 50,000 to 200,000. If the weight average molecular weight is greater than 10,000, sufficient melt tension can be maintained during melt extrusion molding, it is easy to obtain a good sheet-shaped acrylic resin substrate, and the obtained substrate has excellent mechanical properties such as breaking strength. On the other hand, if it is less than 500,000, the molten resin does not become highly viscous, and the generation of foreign substances due to fine wart-shaped irregularities or undissolved substances (high molecular weight substances) on the surface of the substrate obtained by melt extrusion molding can be suppressed, and good viscosity can be obtained. Acrylic resin base material is easy to obtain.

When the acrylic resin has a glutarimide structure and/or a glutaric anhydride structure, the weight average molecular weight of the acrylic resin is preferably 10,000 or more, more preferably 30,000 or more from the viewpoint of increasing mechanical strength, etc. , from the viewpoint of improving moldability into a film, it is preferably 500,000 or less, more preferably 300,000 or less.

The molecular weight distribution (Mw/Mn) of the acrylic resin according to the GPC measurement method is preferably 1 to 10, more preferably 1.1 to 7.0, and even more preferably 1.2 to 1.2 from the viewpoint of adjusting the viscosity to an appropriate level for molding processing. 5.0, most preferably 1.5 to 4.0.

The glass transition temperature (Tg) of the acrylic resin is, for example, 80 to 180°C, preferably about 90 to 170°C. These ranges are preferable because the heat resistance of the acrylic resin is sufficiently high and moldability is good.

[Method for producing acrylic resin]

The method for producing an acrylic resin containing a ring structure in the main chain is not particularly limited, and conventionally known acrylic resin production methods may be followed.

The acrylic resin having a glutaric anhydride structure in the main chain is, for example, an acrylic resin containing a (meth)acrylic acid ester unit and a (meth)acrylic acid unit, and an acrylic resin containing adjacent (meth)acrylic acid ester units and (meth)acrylic acid. It can be formed by intramolecular dealcoholization reaction between units. The method of carrying out the intramolecular dealcoholization reaction is not particularly limited, but can be carried out, for example, by heating. The heating temperature is not particularly limited as long as it is a temperature at which an intramolecular cyclization reaction occurs due to dealcoholization, but for example, 180 to 350°C is acceptable. The heating time can be changed appropriately depending on the composition of the acrylic resin, etc., but for example, 1 to 2 hours is acceptable. In addition, in the intramolecular dealcoholization reaction, a catalyst (for example, an acid catalyst, an alkaline catalyst, a salt catalyst, etc.) may be used.

An acrylic resin having a glutarimide structure in the main chain can be formed, for example, by imidizing an acrylic resin containing a (meth)acrylic acid ester unit. The imidization method may follow a conventionally known method, or may be imidized using ammonia, substituted amine, etc.

The acrylic resin having a maleic anhydride structure and/or a maleimide structure in the main chain, for example, contains (meth)acrylic acid ester and maleic anhydride and/or a maleimide-based compound {[for example, N- Alkyl maleimide (e.g., NC _1-10 alkyl maleimide such as N-methyl maleimide, N-ethyl maleimide, etc.), N-cycloalkyl maleimide (e.g., NC ₃ such as cyclohexyl maleimide) _-20 cycloalkyl maleimide, etc.), N-aryl maleimide (e.g., NC _6-10 aryl maleimide, such as N-phenyl maleimide, etc.), N-aralkyl maleimide (e.g., N-benzyl) NC _7-10 aralkyl maleimide, etc.)], maleimide, etc.} can be obtained by polymerization (for example, radical polymerization, preferably solution polymerization).

An acrylic resin having a lactone ring structure in the main chain, for example, is an acrylic resin containing a 2-(hydroxymethyl)acrylic acid ester unit and a (meth)acrylic acid ester unit, with hydroxyl groups and ester groups as molecules between adjacent units. It can be formed through a dealcoholization reaction. The method of carrying out the intramolecular dealcoholization reaction is not particularly limited, but can be carried out, for example, by heating the acrylic resin. The heating temperature is not particularly limited as long as it is a temperature at which an intramolecular cyclization reaction occurs due to dealcoholization. For example, it is acceptable as long as it is 60 to 350°C. The heating time can be appropriately changed depending on the composition of the acrylic resin, etc., but for example, 1 to 5 hours is acceptable. In addition, in the intramolecular dealcoholization reaction, a catalyst (for example, an organophosphorus compound, an alkaline compound, an organic carboxylate, a carbonate, etc.) may be used.

The acrylic resin having a lactam ring structure in the main chain, for example, is a polymerization component containing (meth)acrylic acid ester and N-vinyl lactam monomer [for example, N-vinyl pyrrolidone monomer (for example, N -Vinyl pyrrolidone, N-vinyl-4-butyl pyrrolidone, N-vinyl-4-propyl pyrrolidone, N-vinyl-4-ethyl pyrrolidone, N-vinyl-4-methyl pyrrolidone, N-vinyl-4-methyl-5-ethyl pyrrolidone, N-vinyl-4-methyl-5-propyl pyrrolidone, N-vinyl-5-methyl-5-ethyl pyrrolidone, N-vinyl-5 -Propyl pyrrolidone, N-vinyl-5-butyl pyrrolidone, etc.), N-vinyl caprolactam monomers (e.g., N-vinyl caprolactam, N-vinyl-6-methyl caprolactam, N-vinyl -6-propyl caprolactam, N-vinyl-7-butyl caprolactam, etc.), etc.] can be obtained by polymerization (for example, radical polymerization, preferably solution polymerization).

The polymerization solvent used in the polymerization of the acrylic resin having a ring structure in the main chain and the acrylic resin serving as its precursor is not particularly limited, but an organic solvent is preferable. The organic solvent is not particularly limited, but examples include aromatic hydrocarbon-based solvents such as toluene, xylene, and ethylbenzene; Ketone-based solvents such as methyl ethyl ketone and methyl isobutyl ketone; Ether-based solvents such as tetrahydrofuran; Alcohol-based solvents such as methanol, ethanol, and butanol can be mentioned. These solvents may be used individually or in combination of two or more types.

In addition, if the boiling point of the polymerization solvent is too high, the remaining volatile content of the acrylic resin ultimately obtained increases, so the polymerization solvent is preferably a solvent with a boiling point of 40 to 200 ° C, and a solvent with a boiling point of 40 to 100 ° C. is more preferable.

The amount of the polymerization solvent used is not particularly limited, but is usually 10 to 200 parts by mass, preferably 15 to 150 parts by mass, relative to 100 parts by mass of the total amount of the monomer composition in the polymerization system. , more preferably 15 to 100 parts by mass.

The polymerization temperature can be appropriately selected depending on the scale of the reaction, etc., but usually, the temperature within the reaction solution is acceptable as long as it is in the range of 30 to 200°C, preferably 50 to 180°C, more preferably 70 to 160°C. In this case, coloring of the acrylic resin can be suppressed, and a molded article with excellent appearance can be obtained.

The polymerization time is not constant depending on the reaction scale, reaction temperature, etc., but is usually ok if appropriately selected in the range of several minutes to 20 hours, preferably 0.5 to 20 hours, more preferably 1 to 10 hours. Moreover, several minutes means about 1 to 10 minutes.

In the polymerization of an acrylic resin having a ring structure in the main chain and an acrylic resin serving as its precursor, a polymerization initiator may be used during polymerization. The polymerization initiator is not particularly limited, and known compounds can be used. Polymerization initiators include, for example, organic peroxides (e.g., cumene hydroperoxide) and azo compounds (e.g., 2,2'-azobis(isobutyronitrile), etc.). The polymerization initiator may be used individually or in combination of two or more types. The amount of polymerization initiator used can be set appropriately depending on the combination of monomers, reaction conditions, etc., and is not particularly limited.

In the polymerization of an acrylic resin having a ring structure in the main chain and an acrylic resin serving as its precursor, a chain transfer agent may be used during polymerization. The chain transfer agent is not particularly limited, and known compounds can be used. Examples of chain transfer agents include thiol-based compounds (eg, dodecyl mercaptan, etc.) and halogen-based compounds (eg, chloroform, etc.). Chain transfer agents may be used individually or in combination of two or more types. The amount of chain transfer agent used can be set appropriately depending on the combination of monomers, reaction conditions, etc., and is not particularly limited.

The polymerization solution after completion of polymerization may be subjected to a devolatilization process described in JP-A-2000-230016, JP-A-2007-262396, JP-A-2007-262399, etc.

In addition, the polymerization solution after completion of polymerization may be filtered. The filtration method is not particularly limited, and for example, filtration may be performed using a filter (for example, a 0.01 to 15 μm filter, etc.).

[Base material composed of acrylic resin]

The shape of the base material (acrylic resin base material) composed of an acrylic resin having a ring structure in the main chain is not particularly limited, and any two-dimensional shape (e.g., film, etc.), three-dimensional shape, etc. is acceptable. The shape of the acrylic resin substrate is usually a film (or sheet) shape.

The manufacturing method of the film is not particularly limited, and conventionally known methods may be used. For example, a film can be obtained by forming an acrylic resin into a film using a known film forming method (for example, solution casting method (solution flow method), melt extrusion method, calendar method, compression molding method, etc.). As a film forming method, solution casting method, melt extrusion method, etc. are preferable.

Furthermore, at the time of film formation, solvents, other resins (e.g., thermoplastic polymers, etc.), and other additives (e.g., ultraviolet absorbers, antioxidants, stabilizers, reinforcing materials, flame retardants, antistatic agents, organic fillers, etc.) are added as desired. , inorganic fillers, anti-blocking agents, resin modifiers, organic fillers, inorganic fillers, plasticizers, lubricants, phase difference reducers, etc.) may be mixed with the acrylic resin.

Examples of thermoplastic polymers include olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly(4-methyl-1-pentene); Halogenated vinyl polymers such as polyvinyl chloride, polyvinylidene chloride, and polyvinyl chloride; Styrene-based polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, and acrylonitrile-butadiene-styrene block copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; Cellulose acylates such as cellulose triacetate, cellulose acetate propionate, and cellulose acetate butylate; polyamides such as nylon 6, nylon 66, and nylon 610; polyacetal; polycarbonate; polyphenylene oxide; polyphenylene sulfide; polyetheretherketone; polysulfone; polyethersulfone; polyoxybenzylene; polyamideimide; These include rubbery polymers such as ABS resin and ASA resin mixed with polybutadiene-based rubber or acrylic-based rubber.

Moreover, the compounding amount of other additives in the film is not particularly limited, but is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass. In particular, when the base material contains acrylic resin and other resins (thermoplastic polymers) as the resin component, acrylic relative to the entire resin component constituting the base material (total amount of acrylic resin and other resins, or the entire solid content of the base material) The proportion of the resin may be, for example, 30% by mass or more (for example, 50% by mass or more), preferably 70% by mass or more, more preferably 80% by mass or more, and especially 85% by mass or more.

Equipment for performing the solution casting method include, for example, a drum-type casting machine, a band-type casting machine, and a spin coater.

The solvent used in the solution casting method is not limited as long as it dissolves the acrylic resin. The solvent includes, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; Aliphatic hydrocarbons such as cyclohexane and decalin; esters such as ethyl acetate and butyl acetate; Ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethers such as tetrahydrofuran and dioxane; Halogenated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; dimethylformamide; It is dimethyl sulfoxide. These solvents can be used one type or two or more types.

Melt extrusion methods include, for example, the T-die method and the inflation method. The molding temperature during melt extrusion is preferably 150 to 350°C, more preferably 200 to 300°C.

When the T-die method is selected, a strip-shaped film can be formed, for example, by installing a T-die at the tip of a known extruder. The formed strip-shaped film may be a film roll wound by a roll. In the melt extrusion method, the process from forming an acrylic resin by mixing materials to forming a film using the resin can be carried out continuously.

The film may be a biaxially stretched film from the viewpoint of increasing mechanical strength. The biaxially stretched film may be either a simultaneously biaxially stretched film or a sequential biaxially stretched film. In addition, the slow axis direction of the stretched film may be the flow direction of the film, may be the width direction, or may be any direction.

Additionally, surface treatment may be performed on the film. Examples of surface treatment include corona discharge treatment and plasma treatment. Furthermore, according to the composition for forming an easily adhesive layer of the present invention, the adhesiveness between the film and the easily adhesive layer is excellent even without surface treatment of the film.

Additionally, in addition to the film and the easily adhesive layer, a low moisture permeability layer may be provided. A low moisture permeability layer is a layer that can reduce the amount of moisture passing through the film substrate. The low moisture permeability layer may be installed on the opposite side of the easily adhesive layer, or may be provided between the film and the easily adhesive layer. The agent capable of forming a low moisture permeability layer is preferably formed of, for example, a resin having a fluorinated alkyl group or a cyclic aliphatic hydrocarbon group (e.g., acrylic resin, polyurethane resin, polyester resin, etc.). Additionally, it is also a preferred form to include rosin, hydrogenated rosin, acid-modified rosin, esterified rosin, etc.

The thickness of the film is not particularly limited and can be adjusted appropriately depending on the application, etc., but is, for example, 1 to 400 μm, preferably 5 to 200 μm, more preferably 10 to 100 μm, and even more preferably 20 μm. It is ~60㎛. For example, when used for applications such as protective films, anti-reflection films, and polarizing films used in image display devices such as liquid crystal displays and organic EL displays, the thickness is preferably 1 to 250 μm, more preferably 10 μm. ~100㎛, more preferably 20~80㎛. By setting these ranges, an excellent film with sufficient strength and transparency can be obtained.

The haze of the film is preferably 1% or less (for example, 0 to 1%), more preferably 0.5% or less (for example, 0 to 0.5%). Haze is measured based on the provisions of JIS K7136. By setting the haze to 1% or less, the color displayed when the film is inserted into an image display device becomes excellent.

The b value of the film is preferably 2% or less (e.g., 0.1 to 2%), more preferably 1.5% or less (e.g., 0.1 to 1.5%), and even more preferably 1% or less (e.g. For example, 0.1 to 1%), most preferably 0.5% or less (for example, 0.1 to 0.5%). By setting the b value to 2% or less, the color displayed when the film is inserted into an image display device becomes excellent.

The Tg of the film is, for example, 110°C or higher (eg, 110°C to 200°C), preferably 115°C to 170°C. Films with such a high Tg are suitable for optical applications, such as because they facilitate placement near heating parts such as light sources in image display devices.

[Easy adhesive base material]

An easily adhesive substrate (adhesive substrate, adhesive film) can be obtained by forming an easily adhesive layer formed of an easily adhesive layer forming composition on an acrylic resin substrate. The easily adhesive layer may be formed on one side or both sides of the acrylic resin substrate, but is usually formed on one side. The easily adhesive layer can be formed, for example, by applying a composition for forming an easily adhesive layer to one side of an acrylic resin substrate and drying it.

The application method of the composition for forming an easily adhesive layer is not particularly limited, but examples include bar coating, roll coating, gravure coating, rod coating, slot orifice coating, curtain coating, and fountain coating. You can. The drying temperature is not particularly limited, but is acceptable as long as it is, for example, 50°C or higher, preferably 90 to 200°C, and more preferably 110 to 180°C. By setting these ranges, for example, a film with excellent color resistance (particularly color resistance in a high-temperature, high-humidity environment) can be obtained.

In an adhesive base material, the thickness of the easily adhesive layer may be, for example, 100 nm to 10 μm, preferably 100 nm to 5 μm, and more preferably 200 nm to 1.5 μm. In these ranges, the effect of improving the adhesion between the acrylic resin substrate and the polarizer by the easily adhesive layer is good. In addition, it is possible to easily suppress phase difference from appearing in the adhesive layer itself.

In the adhesive substrate, the thickness ratio of the acrylic resin substrate and the easily adhesive layer is the former/latter, for example, 1/0.1 to 1/0.001, preferably 1/0.05 to 1/0.002, more preferably 1/0.03. About ~1/0.003 is okay. By setting it within the above range, adhesiveness can be improved.

In addition, stretching treatment may be performed during or after the formation of the adhesive substrate. The stretching may be biaxial stretching. The biaxial stretching may be either simultaneous biaxial stretching or sequential biaxial stretching. In addition, from the viewpoint of improving the adhesion of the adhesive substrate, preventing phase difference reduction, preventing phase difference unevenness (mura), and preventing optical axis unevenness, the formation and stretching of the easily adhesive layer or easily adhesive layer (e.g., lateral stretching) ) can be done at the same time.

The dynamic friction coefficient of the adhesive substrate is preferably 0.1 to 0.6, more preferably 0.1 to 0.4. If it is less than 0.1, it becomes difficult to wind it into a roll shape. If it is greater than 0.6, it becomes difficult to maintain sufficient blocking resistance. Furthermore, the dynamic friction coefficient may be measured according to JIS K7125.

The moisture permeability of the adhesive substrate is preferably 200 g/m ³ ·day or less, more preferably 100 g/m ³ ·day or less, and even more preferably 50 g/m ³ ·day or less. If it exceeds 200 g/m ³ ·day, there is a risk that the adhesiveness may decrease. Furthermore, moisture permeability may be measured according to JIS Z 0208.

The use of the easily adhesive base material is not particularly limited, but it can be suitably used as an optical member. The optical member is not particularly limited, but includes, for example, optical protective films (e.g., protective films for substrates of various optical disks (VD, CD, DVD, MD, LD, etc.), images of liquid crystal displays (LCDs), etc. A polarizer protective film used for a polarizing plate provided in a display device, etc.] can be mentioned.

[Polarizer]

A polarizing plate (polarizing film) can be formed by adhering an easily adhesive base material to a polarizer (polarizing film). A polarizing plate can be obtained, for example, by bonding an easily adhesive base material to at least one side of a polarizer through an easily adhesive layer.

The polarizing plate may have at least a laminated unit in which a base material made of an acrylic resin having a ring structure in the main chain and a polarizer are laminated through an easily adhesive layer formed of a composition for easily adhesive layer formation.

The polarizer is not particularly limited, and examples include polyvinyl alcohol-based films. As the polyvinyl alcohol-based film, one dyed with iodine, one dyed with a dichroic dye, etc. can be used.

As a polyvinyl alcohol-based film, for example, an aqueous polyvinyl alcohol solution is formed, and then uniaxially stretched and dyed, or dyed and then uniaxially stretched, and then treated for durability, preferably using a boron compound. It's okay too. In addition, the film thickness of the polarizer is preferably about 5 to 30 μm, and more preferably about 10 to 20 μm.

In addition, the easily adhesive base material and the polarizer (polarizing film) may be adhered through an adhesive layer between the easily adhesive layer and the polarizer. The adhesive is not particularly limited, and anything that can be used as an adhesive between a polarizer protective film and a polarizer can be used. Adhesives include, for example, vinyl acetate adhesives, PVA adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, polyurethane adhesives, isocyanate adhesives, epoxy adhesives, melamine adhesives, chloroprene rubber adhesives, and nitrile. Synthetic rubber adhesives such as rubber adhesives, styrene rubber adhesives, and silicone rubber adhesives may be included. These adhesives may be used individually or in combination of two or more types. Among these adhesives, polyurethane-based adhesives, isocyanate-based adhesives, and acrylic adhesives are preferred, and polyurethane-based adhesives are more preferred. In addition, the form of the adhesive is not particularly limited, and for example, it may be solvent-based, aqueous-based (water-dispersible, water-soluble), or non-solvent-based.

[Image display device]

The present invention also includes an image display device provided with the polarizing plate of the present invention described above. Examples of image display devices include liquid crystal displays (LCDs). A liquid crystal display device usually includes a liquid crystal cell and a polarizing plate disposed on at least one side of the liquid crystal cell. Furthermore, the manufacturing method of the image display device is not particularly limited, and conventionally known methods may be used.

The present invention is not limited to each of the above-described embodiments, and various changes are possible within the scope shown in the claims, and the present invention also covers embodiments that can be obtained by appropriately combining the technical means disclosed in the other embodiments. included in the scope.

[Example]

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not originally limited by the following examples, and may be implemented with appropriate changes within the scope suitable for the previous and latter purposes. It is possible, and they are all included in the technical scope of the present invention. Additionally, samples for measuring film properties were obtained from the central portion in the width direction.

<Weight average molecular weight>

The weight average molecular weight was determined by gel permeation chromatography (GPC) under the following conditions.

System: Tosoh GPC system HLC-8220

Development solvent: chloroform (made by Wako Pure Chemical Industries, special grade), flow rate: 0.6 ml/min.

Standard sample: TSK standard polystyrene (Tosoh Corporation, PS-oligomer kit)

Measurement side column configuration: guide column (TSKguardcolumn SuperHZ-L, manufactured by Tosoh), two separation columns (TSKgel SuperHZM-M, manufactured by Tosoh) connected in series

Reference column configuration: Reference column (Tosoh Corporation, TSKgel SuperH-RC)

<Glass transition temperature>

The glass transition temperature (Tg) was determined based on the provisions of JIS K7121. Specifically, using a differential scanning calorimeter (DSC-8230, manufactured by Rigaku Co., Ltd.), a sample of about 10 mg was heated from room temperature to 200°C at a temperature increase rate of 20°C/min under a nitrogen gas atmosphere, and the starting point method was calculated from the DSC curve obtained. Calculated by . For reference, α-alumina was used.

<Average film thickness>

The thickness of the film was measured at intervals of 20 mm in the width direction using a Digimatic Micrometer (minimum display amount 0.001 mm) manufactured by Mitutoyo Co., Ltd., and the average value was obtained.

<Haize>

The haze of the film was measured in accordance with the provisions of JIS K7136 using a turbidity meter (“NDH-5000” manufactured by Nippon Denshoku Kogyo Co., Ltd.).

<Average particle diameter and particle size distribution of fine particles>

The average particle diameter and particle size distribution of the fine particles were measured using a particle size distribution measuring device (“CPS Disc Centrifuge Model DC12000” manufactured by CPS Instruments. inc.). Specifically, for fine particles dispersed in water, the equivalent spherical distribution in a range of 100 nm or more is measured as the primary particle diameter with the measuring device, and the obtained distribution is integrated from the opposing side. The particle size of the particles with a volume fraction of 50% was determined, and this was taken as the average primary particle diameter (d50) of the fine particles. Separately from this, in the distribution, the particle size (d25) of the particles with an integrated volume fraction of 25% and the particle size (d75) of the particles with an integrated volume fraction of 75% are calculated, and the ratio (d25/d75) is calculated as fine particles. The particle size distribution was set to .

<Heat water resistance>

From the obtained optical film, two film pieces of 50 It was dried at 80°C for 24 hours. On top of that, 5 sheets were cut out in a size of 10 x 50 mm to serve as test samples. Next, five test samples were immersed in hot water at 60°C for 2 hours, then the grip portion was held and peeled in the direction of 90°C at a speed of 1 mm/sec to determine whether there was peeling at the interface between the base film and the easily adhesive layer. Confirmed. Judgment was made based on the following standards. In addition, the peeling position of the easily adhesive layer was confirmed by the presence or absence of characteristic absorption in the polyurethane resin using an infrared spectrophotometer (Nexus670, manufactured by Thermo-Nicolet).

○: No sample peeled from the interface between the base film and the easily adhesive layer.

△: 1 to 3 out of 5 samples peeled from the interface between the base film and the easily adhesive layer.

×: More than 4 out of 5 samples peeled from the interface between the base film and the easily adhesive layer

<Moisture and heat resistance>

Five test samples manufactured in the same way as the hot water resistance test samples were placed in a constant temperature and humidity chamber at 85°C and 85%RH, taken out after 200 hours, and the exposed core was held and peeled in the direction of 90°C at a speed of 1 mm/sec. Thus, the presence or absence of peeling at the interface between the base film and the easily adhesive layer was confirmed. The judgment was made based on the following criteria. In addition, the peeling position of the easily adhesive layer was confirmed by the presence or absence of characteristic absorption in the polyurethane resin using an infrared spectrophotometer (Nexus670, manufactured by Thermo-Nicolet).

○: No sample peeled from the interface between the base film and the easily adhesive layer.

△: 1 to 3 out of 5 samples peeled from the interface between the base film and the easily adhesive layer.

×: More than 4 out of 5 samples peeled from the interface between the base film and the easily adhesive layer

(Preparation Example 1-1 [Resin composition for forming base layer (A-1)])

In a reaction pot equipped with a stirring device, a temperature sensor, a cooling pipe, and a nitrogen introduction pipe, 40 parts by weight of methyl methacrylate (MMA), 10 parts by weight of methyl 2-(hydroxymethyl)acrylate (MHMA), and toluene as a polymerization solvent. 50 parts by weight and 0.025 parts by weight of antioxidant (Adekastab 2112, manufactured by ADEKA) were added, and the temperature was raised to 105°C while passing nitrogen through the mixture. At the point when reflux with temperature increase begins, 0.05 parts by weight of t-amyl peroxy isononanoate (manufactured by Arkema Yoshitomi, product name: Luperox 570) is added as a polymerization initiator, and at the same time, the t-amyl peroxy isononanoate is added. Solution polymerization was carried out under reflux at about 105 to 110°C while 0.10 parts by weight of nanoate was added dropwise over 2 hours, followed by aging for 4 hours. Next, 0.05 parts by weight of a stearyl phosphate/distearyl phosphate mixture (Phoslex A-18, manufactured by Sakai Chemical Industry Co., Ltd.) was added as a catalyst for the cyclization condensation reaction (cyclization catalyst) to the obtained polymerization solution, and refluxed at about 90 to 110°C. A cyclization condensation reaction to form a lactam ring structure was carried out for 5 hours under low temperature. Next, the temperature of the obtained polymerization solution was raised to 240°C through a heat exchanger, and the cyclization condensation reaction was further advanced at that temperature. Subsequently, the obtained polymerization solution was adjusted to a barrel temperature of 240°C, a rotation speed of 100 rpm, a degree of reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), and 1 rear vent and 4 front vents (1st, 2nd, and 3rd from the upstream side). , referred to as the fourth vent), a vent-type propeller twin-screw extruder (L/D) in which a side feeder is installed between the third and fourth vents, and a leaf disk-type polymer filter (filtration accuracy of 5 μm) is placed at the tip. =52), it was introduced at a processing speed of 90 parts by weight/hour (resin amount converted), and devolatilization was performed. At that time, a separately prepared mixed solution of antioxidant/cyclization catalyst deactivator was added to the back of the first vent at an injection rate of 1.06 parts by weight/hour, and ion-exchanged water was added to the second and third vents at an injection rate of 0.34 parts by weight/hour. From behind, each was put in. As a mixed solution of antioxidant/cyclization catalyst activator, 50 parts by weight of antioxidant (Irganox 1010, manufactured by BASF Japan) and 35 parts by weight of zinc octylate (Nickaoctix Zinc 3.6%, manufactured by Nippon Chemical Industry Co., Ltd.) as a quencher. , a solution dissolved in 200 parts by weight of toluene was used. In addition, during devolatilization, pellets of styrene-acrylonitrile copolymer (AS resin: styrene unit/acrylonitrile unit ratio of 73%/27% by weight, weight average molecular weight of 220,000) are fed to the side feeder. It was added at an injection rate of 10 parts by weight/hour. After completion of devolatilization, the resin in a heat-dissolved state remaining in the extruder is discharged from the tip of the extruder while being filtered through a polymer filter, and pelletized by a pelletizer to form a (meth)acrylic polymer having a lactam ring structure in the main chain. A transparent pellet (A-1) of an acrylic resin was obtained as the main component (content of 90% by weight) and a styrene-acrylonitrile copolymer thereon at a content of 10% by weight. The weight average molecular weight of the resin composition constituting the resin pellet (A-1) was 132000 and Tg was 125°C.

(Preparation Example 1-2 [Resin composition for forming base layer (A-2)])

In a reaction pot equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen gas introduction tube, 79.4 parts by weight of methyl methacrylate (MMA), 20.6 parts by weight of methacrylic acid (MAA), 90.0 parts by weight of toluene and methanol as polymerization solvents. 22.5 parts by weight of a mixed solvent and 0.05 parts by weight of an antioxidant (ADEKASTAB 2112, manufactured by ADEKA) were added, and the temperature was raised to 73° C. while passing nitrogen gas through the reaction pot. At the point when reflux due to temperature increase began, 0.25 parts by weight of dimethyl-2, 2'-azobis(2-methylpropionate) (manufactured by Wako Pure Chemical Industries, Ltd., brand name: V-601) as a polymerization initiator was added into the reaction pot. At the same time, a solution of 0.35 parts by weight of dimethyl-2,2'-azobis(2-methylpropionate) dissolved in a mixed solvent of 7.3 parts by weight of toluene and 1.8 parts by weight of methanol was added dropwise into the reaction pot over a period of 2 hours, at about 71%. Solution polymerization was performed under reflux at ~76°C, and after completion of the dropwise addition of dimethyl-2,2'-azobis(2-methylpropionate), aging was performed for 4 hours. The content of repeating units derived from methacrylic acid in the (meth)acrylic resin contained in the polymer solution obtained above was 20.6% by weight. Additionally, the weight average molecular weight of the (meth)acrylic resin was 110,000. Next, a solution of 0.05 parts by weight of sodium methoxide, which is a catalyst for the cyclization condensation reaction (cyclization catalyst), dissolved in 5.0 parts by weight of methanol was added dropwise to the polymerization solution in the reaction pot at a temperature of about 65 to 70°C over 20 minutes to form a uniform solution. It was used as a polymerization solution. The polymerization solution obtained above was extruded into a vent-type screw twin-screw extruder (hole diameter: 15 mm, L/) with a barrel temperature of 280°C, a rotation speed of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), and one rear vent and two front vents. D: 45) was introduced at a processing rate of 420 g/h in terms of the amount of resin, devolatilized in this twin-screw extruder, and extruded with an in-shaft residence time of about 3.2 minutes to produce ((), which has a glutaric anhydride structure in the main chain. Transparent pellets (A-2) of meta)acrylic resin were obtained. The weight average molecular weight of the resin composition constituting the resin pellet (A-2) was 97000, and the glass transition temperature was 131°C. Additionally, the anhydrous glutar oxidation rate of the (meth)acrylic resin was 16.3%.

(Preparation Example 1-3 [Resin composition for forming base layer (A-3)])

In a reaction vessel equipped with a stirring device, a temperature sensor, a cooling tube, a nitrogen introduction tube, and a dropping funnel, 90 parts by mass of methyl methacrylate (MMA), 10 parts by mass of N-phenylmaleimide (PMI), and an antioxidant (ade) were added. 0.05 parts by mass of Kastab 2112 (manufactured by ADEKA), 0.1 parts by mass of dodecyl mercaptan (DM) as a chain transfer agent, and 80.5 parts by mass of toluene were added, and the contents were heated to 105°C while nitrogen gas was introduced thereto. At the point when reflux due to temperature increase began, 0.103 parts by mass of t-amyl peroxy isononanoate (manufactured by Arkema Yoshitomi, brand name: Luperox 570) was added as a polymerization initiator, and the above t- was added to 21 parts by mass of toluene. Solution polymerization was carried out while a solution containing 0.205 parts by mass of amyl peroxy isononanoate was added dropwise over 2 hours. After the dropwise addition was completed, aging was performed for 6 hours. Next, the obtained polymerization solution was mixed with a barrel temperature of 240°C, a rotation speed of 100 rpm, a reduced pressure of 10.3 to 400 hPa (10 to 300 mmHg), 1 rear vent and 4 front vents (1st, 2nd and 3rd from the upstream side). , (referred to as the fourth vent) was introduced into a vent-type propeller twin-screw extruder (ϕ = 29.75 mm, L/D = 30) at a processing speed of 2.0 kg/hour in conversion of resin amount, and devolatilization was performed. At that time, the separately prepared antioxidant solution was injected from behind the first vent at an injection rate of 0.03 kg/hour, and ion-exchanged water was injected from behind the third vent at an injection rate of 0.01 kg/hour. For the antioxidant solution, a solution in which 50 parts by mass of an antioxidant (Sumitomo Chemical, Sumirizer GS) was dissolved in 235 parts by mass of toluene was used. After completion of devolatilization, the resin composition in a thermally dissolved state remaining in the extruder is discharged from the tip of the extruder, pelletized by a pelletizer, and transparent pellets (A-) of (meth)acrylic resin having a maleimide structure in the main chain are produced. 3) was obtained. The weight average molecular weight of the resin composition constituting the resin pellet (A-3) was 129000 and Tg was 129°C.

(Preparation Example 2 [Preparation of coating liquid for easy adhesive layer formation (P-1)])

11.2 parts by weight of urethane resin having a carboxyl group (Daiichi Kogyo Pharmaceutical Co., Ltd., Superflex 210, solid content 35% by weight), glycerol polyglycidyl ether as a crosslinking agent (Nagase Chemtex Co., Ltd., Denacol EX-313, epoxy equivalent 141, viscosity 150 mPa·s, number of functional groups 2 to 3, number of atoms in the longest atomic chain 7) 0.6 parts by weight, emulsion containing amorphous silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle) Diameter) 0.11 ㎛, particle size distribution 1.1, solid content 15.5% by weight) 1.3 parts by weight, and 26.9 parts by weight of pure water were mixed to obtain an emulsion-like dispersion coating liquid for easily forming an adhesive layer (P-1).

(Preparation Example 3 [Preparation of coating liquid for easy adhesive layer formation (P-2)])

11.2 parts by weight of urethane resin (Daiichi Kogyo Pharmaceutical Co., Ltd., Superflex 210, solid content 35% by weight), glycerol polyglycidyl ether as a crosslinking agent (Nagase Chemtex Co., Ltd., Denacol EX-313, epoxy equivalent 141, viscosity 150 mPa·s) , number of functional groups 2 to 3, number of atoms in the longest atomic chain 7) 1.0 parts by weight, emulsion containing amorphous silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle diameter (primary particle diameter) 0.11 1.3 parts by weight of ㎛, particle size distribution 1.1, solid content 15.5% by weight) and 26.6 parts by weight of pure water were mixed to obtain a coating liquid for easily forming an adhesive layer (P-2), which is an emulsion-like dispersion.

(Preparation Example 4 [Preparation of coating liquid for easy adhesive layer formation (P-3)])

11.2 parts by weight of urethane resin (Daiichi Kogyo Pharmaceutical Co., Ltd., Superflex 210, solid content 35% by weight), glycerol polyglycidyl ether as a crosslinking agent (Nagase Chemtex Co., Ltd., Denacol EX-313, epoxy equivalent 141, viscosity 150 mPa·s) , number of functional groups 2 to 3, number of atoms in the longest atomic chain 7) 1.0 parts by weight, emulsion containing amorphous silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahoster KE-W30, average particle diameter (primary particle diameter) 0.28 0.1 part by weight (μm, particle size distribution 1.1, solid content 20% by weight) and 0.8 parts by weight (Nippon Shokubai Co., Ltd., Seahorse KE-W10, average particle diameter (primary particle diameter) 0.11 μm, particle size distribution 1.1, solid content 15.5% by weight) , and 27.0 parts by weight of pure water were mixed to obtain a coating liquid for easily forming an adhesive layer (P-3), which is an emulsion-like dispersion.

(Preparation Example 5 [Preparation of coating liquid (P-4) for easy adhesive layer formation])

11.2 parts by weight of urethane resin (Daiichi Kogyo Pharmaceutical Co., Ltd., Superflex 210, solid content 35% by weight), glycerol polyglycidyl ether as a crosslinking agent (Nagase Chemtex Co., Ltd., Denacol EX-313, epoxy equivalent 141, viscosity 150 mPa·s) , number of functional groups 2 to 3, number of atoms in the longest atomic chain 7) 1.0 parts by weight, water-based colloidal silica (Nissan Chemical Co., Ltd., Snowtex C, average particle diameter (primary particle diameter) 10 to 15 nm, solid content 20.5% by weight) 3.8 weight 1 part and 24.0 parts by weight of pure water were mixed to obtain a coating liquid for easily forming an adhesive layer (P-4), which is an emulsion-like dispersion.

(Preparation Example 6 [Preparation of coating liquid for easy adhesive layer formation (P-5)])

11.2 parts by weight of urethane resin (Superflex 210, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., 35% by weight of solids), 3.9 parts by weight of a polymer containing an oxazoline group as a crosslinking agent (Epocross WS-700, manufactured by Nippon Shokubai Co., Ltd., 25% by weight of solids) , 1.3 parts by weight of an emulsion containing amorphous silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahorse KE-W10, average particle size (primary particle diameter) 0.11 ㎛, particle size distribution 1.1, solid content 15.5% by weight), and pure water. 23.4 parts by weight were mixed to obtain a coating liquid for easily forming an adhesive layer (P-5), which is an emulsion-like dispersion.

(Preparation Example 7 [Preparation of coating liquid for easy adhesive layer formation (P-6)])

11.2 parts by weight of urethane resin (Daiichi Kogyo Pharmaceutical Co., Ltd., Superflex 210, solid content 35% by weight), 2.5 parts by weight of a polymer containing a carbodiimide group as a crosslinking agent (Carbodilite V-02, manufactured by Nisshinbo Chemical Co., Ltd., solid content 40% by weight) Part, 1.3 parts by weight of an emulsion containing amorphous silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahorse KE-W10, average particle size (primary particle diameter) 0.11 ㎛, particle size distribution 1.1, solid content 15.5% by weight), and pure water. 24.9 parts by weight of water was mixed to obtain a coating liquid for easily forming an adhesive layer (P-6), which is an emulsion-like dispersion.

(Example 1)

The resin composition for forming a base layer (A-1) obtained in Preparation Example 1-1 was melt-extruded at 282°C using a single-screw extruder equipped with a T-die and a polymer filter (filtration accuracy: 5 μm) at the tip, and then extruded at 125°C. After discharging onto the cooling roll and forming an unstretched film with a thickness of 192 ㎛, it is continuously supplied as is to an oven longitudinal stretching machine, the temperature of the oven is set to 140°C, and stretching is performed in the longitudinal direction at a stretching ratio of 2.0 times. , a laterally stretched film with a thickness of 136 μm was obtained. Next, the coating liquid for forming an easy adhesive layer (P-1) obtained in Production Example 2 was applied to one side of the obtained laterally stretched film using a bar coater (#8) so that the thickness of the coated film after drying was 1.3 μm, and then applied to both ends. A position of 20 mm from the A ㎛ optical film was obtained.

(Example 2)

As a coating liquid for forming an easily adhesive layer, the coating liquid for forming an easily adhesive layer (P-2) obtained in Production Example 3 was used in the same manner as in Example 1, and a 40 μm optical film having an easily adhesive layer on one side was made. got it

(Example 3)

As a coating liquid for forming an easily adhesive layer, the coating liquid for forming an easily adhesive layer (P-3) obtained in Production Example 4 was used in the same manner as in Example 1, and a 40 μm optical film having an easily adhesive layer on one side was made. got it

(Example 4)

As a coating liquid for forming an easily adhesive layer, the coating liquid for forming an easily adhesive layer (P-4) obtained in Production Example 5 was used in the same manner as in Example 1, and a 40 μm optical film having an easily adhesive layer on one side was made. got it

(Example 5)

The resin composition for forming a base layer (A-2) obtained in Production Example 1-2 was melt-extruded at 290°C using a single-screw extruder equipped with a T-die and a polymer filter (filtering degree of 5 μm) at the tip, and then extruded at 131°C. After discharging onto the cooling roll and forming an unstretched film with a thickness of 192 ㎛, it is continuously supplied as is to an oven longitudinal stretching machine, the temperature of the oven is set to 146°C, and stretching is performed in the longitudinal direction at a stretching ratio of 2.0 times. , a laterally stretched film with a thickness of 136 μm was obtained. Next, the coating liquid for forming an easy adhesive layer (P-1) obtained in Production Example 2 was applied to one side of the obtained laterally stretched film using a bar coater (#8) so that the thickness of the coated film after drying was 1.3 μm, and then applied to both ends. A position 20 mm from the A ㎛ optical film was obtained.

(Example 6)

The resin composition for forming a base layer (A-3) obtained in Production Example 1-3 was melt-extruded at 290°C using a single-screw extruder equipped with a T-die and a polymer filter (filtering degree of 5 μm) at the tip, and then extruded at 129°C. After discharging onto the cooling roll and forming an unstretched film with a thickness of 192 ㎛, it is continuously supplied as is to an oven longitudinal stretching machine, the temperature of the oven is set to 144°C, and stretching is performed in the longitudinal direction at a stretching ratio of 2.0 times. , a laterally stretched film with a thickness of 136 μm was obtained. Next, the coating liquid for forming an easy adhesive layer (P-1) obtained in Production Example 2 was applied to one side of the obtained laterally stretched film using a bar coater (#8) so that the thickness of the coated film after drying was 1.3 μm, and then applied to both ends. A position 20 mm from An optical film was obtained.

(Example 7)

As a resin composition for forming a base layer (A-4), a (meth)acrylic resin (manufactured by Asahi Kasei Co., Ltd., Delpet 980N, Tg120°C) having a maleic anhydride structure in the main chain, a polymer filter (filtration accuracy of 5 μm) at the tip, and It is melt-extruded at 275°C using a single-screw extruder equipped with a T-die, discharged onto a cooling roll at 120°C, and an unstretched film with a thickness of 192 ㎛ is formed into a film, which is then continuously supplied to an oven longitudinal stretching machine and placed in an oven. The temperature was set to 135°C, and stretching was performed in the longitudinal direction at a stretching ratio of 2.0 to obtain a laterally stretched film with a thickness of 136 μm. Next, the coating liquid for forming an easy adhesive layer (P-1) obtained in Production Example 2 was applied to one side of the obtained laterally stretched film using a bar coater (#8) so that the thickness of the coated film after drying was 1.3 μm, and then applied to both ends. A position 20 mm from An optical film was obtained.

(Example 8)

As a resin composition for forming a base layer (A-5), a (meth)acrylic resin (PLEXIMID8813, weight average molecular weight 87000, Tg 131°C, manufactured by Daicel Evonik, Inc.) having a glutarimide structure in the main chain was placed at the tip of the polymer filter ( It is melt-extruded at 290°C using a single-screw extruder equipped with a filtration accuracy of 5㎛ and a T-die, discharged onto a cooling roll at 120°C, and an unstretched film with a thickness of 192㎛ is formed, followed by continuous oven longitudinal stretching. was supplied to the oven, the temperature of the oven was set to 146°C, and stretching was performed in the longitudinal direction at a stretching ratio of 2.0 to obtain a laterally stretched film with a thickness of 136 μm. Next, the coating liquid for forming an easy adhesive layer (P-1) obtained in Production Example 2 was applied to one side of the obtained laterally stretched film using a bar coater (#8) so that the thickness of the coated film after drying was 1.3 μm, and then applied to both ends. A position 20 mm from An optical film was obtained.

(Comparative Example 1)

As a coating liquid for forming an easily adhesive layer, the coating liquid for forming an easily adhesive layer (P-5) obtained in Production Example 6 was used in the same manner as in Example 1, and a 40 μm optical film having an easily adhesive layer on one side was made. got it

(Comparative Example 2)

As a coating liquid for forming an easily adhesive layer, the coating liquid for forming an easily adhesive layer (P-6) obtained in Production Example 7 was used in the same manner as in Example 1, and a 40 μm optical film having an easily adhesive layer on one side was made. got it

The evaluation results of the optical films produced and obtained in each Example and Comparative Example are summarized in Table 1 below.

[Table 1]

As shown in Examples 1 to 8, the composition for forming an easily adhesive layer contains a polyurethane resin (A) having a carboxyl group and an epoxy compound (B), thereby forming an easily adhesive base material with excellent adhesiveness even under high temperature and high humidity. What can be achieved has been confirmed. On the other hand, in Comparative Example 1, where the composition for forming an easily adhesive layer contained an oxazoline group-containing polymer rather than an epoxy compound, and Comparative Example 2, which contained a carbodiimide group-containing polymer, the easily adhesive substrate under high temperature and high humidity It was confirmed that the adhesiveness deteriorated. From the above, according to the composition for forming an easily adhesive layer of the present invention, an easily adhesive layer excellent in adhesion to the acrylic resin substrate can be formed on an acrylic resin substrate, and this easily adhesive layer has excellent adhesiveness even under high temperature and high humidity. Therefore, it can be bonded with high adhesiveness to other functional films (e.g., polarizer, etc.) under high temperature and high humidity.

According to the present invention, an easily adhesive layer that is excellent in adhesion to the acrylic resin substrate even under high temperature and high humidity can be formed on the acrylic resin substrate. By laminating the acrylic resin substrate and the polarizer through this easy adhesive layer, even under high temperature and high humidity. A polarizing plate with excellent adhesion between the acrylic resin substrate and the polarizer, and an image display device equipped with this polarizing plate can be obtained.

Claims (12)

A composition for forming an easily adhesive layer on a substrate composed of an acrylic resin having a ring structure in the main chain, and comprising a polyurethane resin (A) having a carboxyl group and an epoxy compound (B). The composition according to claim 1, wherein the ring structure has at least one structure selected from maleic anhydride structure, maleimide structure, glutaric anhydride structure, glutarimide structure, lactam ring structure, and lactone ring structure. The composition according to claim 1 or 2, wherein the epoxy compound (B) contains an aliphatic epoxy compound. The composition according to claim 1 or 2, wherein the epoxy compound (B) satisfies the requirements of an epoxy equivalent weight of 200 g/equivalent or less and a viscosity of 2000 mPa·s or less. The composition according to claim 3, wherein the epoxy compound (B) contains an aliphatic polyol polyglycidyl ether and satisfies an epoxy equivalent weight of 170 g/equivalent or less. The composition according to claim 1 or 2, wherein the ratio of the polyurethane resin (A) and the epoxy compound (B) is former/latter (weight ratio) = 99/1 to 10/90. An easily adhesive substrate comprising a substrate composed of an acrylic resin having a ring structure in the main chain, and an easily adhesive layer formed on the substrate with the composition according to claim 1 or 2. The easily adhesive substrate according to claim 7, wherein the thickness ratio between the substrate and the easily adhesive layer is former/latter = 1/0.1 to 1/0.001. The easily adhesive substrate according to claim 8 for optical use. The easily adhesive substrate according to claim 9 for bonding to a polarizer. A polarizing plate having a lamination unit in which the easily adhesive substrate according to claim 10 and a polarizer are laminated. An image display device equipped with the polarizing plate according to claim 11.