CN120603914A - Adhesive composition, adhesive layer, optical film with adhesive layer, and display device - Google Patents

Abstract

The present invention aims to provide an adhesive having excellent heat resistance and durability. The solution relates to an adhesive composition comprising a (meth)acrylic resin (A), a crosslinking agent (B), and a silane compound (C), wherein the (meth)acrylic resin (A) comprises, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A), structural units derived from an alkyl methacrylate (a) having a homopolymer glass transition temperature of 30°C or higher, in an amount of 1 part by mass or more and 15 parts by mass or less, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A), structural units derived from a hydroxyl-containing (meth)acrylate (b) represented by formula (I) in an amount of 0.3 parts by mass or more and 5.5 parts by mass or less, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A), and structural units derived from a carboxyl group-containing monomer (c), wherein the mass ratio (c)/(b) of the structural units derived from the carboxyl group-containing monomer (c) to the structural units derived from the hydroxyl-containing (meth)acrylate (b) represented by formula (I) is 0.06 or more and 1.0 or less.

Description

Adhesive composition, adhesive layer, optical film with adhesive layer, and display device

Technical Field

The present invention relates to an adhesive composition, an adhesive layer containing the adhesive composition, and an optical film with the adhesive layer.

Background

An optical film such as a polarizing plate used in an image display device such as a liquid crystal display device or an organic electroluminescence (organic EL) display device is often bonded to another member (for example, an image display element such as a liquid crystal cell in the liquid crystal display device) via an adhesive layer. Patent document 1 proposes, as a composition for forming a pressure-sensitive adhesive for a polarizing plate having durability under a high-temperature environment, a pressure-sensitive adhesive composition for a polarizing plate containing an acrylic resin and an ionic compound, the acrylic resin containing a structural part derived from methyl methacrylate, a structural part derived from butyl acrylate, a structural part derived from methyl acrylate, and 4-hydroxybutyl acrylate.

Prior art literature

Patent literature

Patent document 1 Japanese patent application laid-open No. 2022-25417

Disclosure of Invention

Problems to be solved by the invention

An adhesive used for an optical film for vehicle use and the like is required to have improved heat resistance and durability under a more severe high-temperature environment. However, it is difficult for the adhesive to ensure its heat resistance durability under more severe high temperature environments.

The object of the present invention is to provide an adhesive exhibiting excellent heat resistance and durability.

Means for solving the problems

The invention provides the following adhesive composition, adhesive layer, optical film with adhesive layer and display device.

[1] An adhesive composition comprising a (meth) acrylic resin (A), a crosslinking agent (B), and a silane compound (C),

The (meth) acrylic resin (a) contains:

A structural unit derived from an alkyl methacrylate (a) having a homopolymer glass transition temperature of 30 ℃ or higher, in an amount of 1 to 15 parts by mass based on 100 parts by mass of the total structural units constituting the (meth) acrylic resin (a);

A structural unit derived from a hydroxyl group-containing (meth) acrylate (b) represented by the following formula (I) in an amount of 0.3 to 5.5 parts by mass based on 100 parts by mass of the total structural units constituting the (meth) acrylic resin (A), and

Structural units derived from carboxyl-containing monomers (c),

The mass ratio (c)/(b) of the structural unit derived from the carboxyl group-containing monomer (c) to the structural unit derived from the hydroxyl group-containing (meth) acrylate (b) represented by the formula (I) is 0.06 or more and 1.0 or less,

[ Chemical formula 1]

In the formula (I) of the formula (I),

N represents an integer of 1 to 5,

A ¹ represents a hydrogen atom or an alkyl group,

X ¹ represents a methylene group optionally having a substituent, and when n is 2 or more, X ¹ is optionally the same or different.

[2] The adhesive composition according to [1], wherein the homopolymer has a glass transition temperature of at least 80 ℃ and the homopolymer of the alkyl methacrylate (a) has a glass transition temperature of at least 30 ℃.

[3] The adhesive composition according to [1] or [2], wherein the alkyl methacrylate (a) having a glass transition temperature of 30 ℃ or higher of the homopolymer contains at least 1 selected from the group consisting of methyl methacrylate, t-butyl methacrylate, isobornyl methacrylate and cyclohexyl methacrylate.

[4] The adhesive composition according to any one of [1] to [3], wherein the weight average molecular weight of the (meth) acrylic resin (A) is 100 to 320 [ mu ] n.

[5] The adhesive composition according to any one of [1] to [4], wherein the crosslinking agent (B) contains an aromatic isocyanate compound, and the adhesive composition contains 0.2 parts by mass or more and 5.0 parts by mass or less of the crosslinking agent (B) per 100 parts by mass of the (meth) acrylic resin (A).

[6] An adhesive layer comprising the adhesive composition according to any one of [1] to [5 ].

[7] An optical film with an adhesive layer comprising an optical film and the adhesive layer of [6] laminated on the optical film.

[8] The optical film with an adhesive layer according to [7], wherein the aforementioned optical film comprises a polarizing plate.

[9] A display device comprising the optical film with an adhesive layer of [7] or [8 ].

[10] An adhesive layer having a rupture energy per unit volume of 1.2X10 ⁶J/m³ or more.

Effects of the invention

According to the present invention, an adhesive exhibiting excellent heat resistance and durability can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of an optical film with an adhesive layer according to the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the optical film with an adhesive layer according to the present invention.

Fig. 3 is a schematic cross-sectional view showing still another example of the optical film with an adhesive layer according to the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all the drawings below, the scale of each constituent element is appropriately adjusted to display the constituent elements for easy understanding, and the scale of each constituent element shown in the drawings does not necessarily coincide with the scale of the actual constituent element.

< Adhesive composition >

(1) (Meth) acrylic resin (A)

The (meth) acrylic resin (A) contained in the adhesive composition of the present invention comprises, per 100 parts by mass of all the structural units constituting the (meth) acrylic resin (A), 1 to 15 parts by mass of structural units derived from an alkyl methacrylate (a) having a glass transition temperature (hereinafter also referred to as Tg) of 30 ℃ or higher, per 100 parts by mass of all the structural units constituting the (meth) acrylic resin (A), 0.3 to 5.5 parts by mass of structural units derived from a hydroxy group-containing (meth) acrylate (b) represented by the following formula (I), and structural units derived from a carboxyl group-containing monomer (C),

[ Chemical formula 2]

In the formula (I) of the formula (I),

N represents an integer of 1 to 5,

A ¹ represents a hydrogen atom or an alkyl group,

X ¹ represents a methylene group optionally having a substituent, and when n is 2 or more, X ¹ is optionally the same or different. In the present specification, (meth) acrylic acid means either acrylic acid or methacrylic acid. (meth) acrylate means either acrylate or methacrylate.

The alkyl methacrylate (a) is an alkyl methacrylate having a homopolymer glass transition temperature (Tg) of 30 ℃ or higher. The Tg of the homopolymer of alkyl methacrylate may be a literature value such as POLYMER HANDBOOK (Wiley-Interscience). From the viewpoints of mechanical strength and heat resistance and durability, the Tg of the homopolymer of the alkyl methacrylate (a) is preferably 50 ℃ or higher, more preferably 60 ℃ or higher, and still more preferably 80 ℃ or higher. The upper limit of Tg of the homopolymer of the alkyl methacrylate (a) is not particularly limited, and is usually 250℃or less.

Specific examples of the alkyl methacrylate (a) include methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, propyl methacrylate, isopropyl methacrylate, alkyl methacrylates having a linear or branched alkyl group having 1 to 6 carbon atoms such as 3, 3-dimethylbutyl methacrylate and 3, 3-dimethyl-2-butyl methacrylate, and n-stearyl methacrylate. The alkyl methacrylate (a) may be an alkyl methacrylate (cycloalkyl methacrylate) having an alicyclic structure. The alicyclic structure may be a cycloalkane structure having usually 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. As a specific example of the alkyl methacrylate having an alicyclic structure, examples thereof include isobornyl methacrylate, cyclohexyl methacrylate dicyclopentanyl methacrylate, cyclododecyl methacrylate methylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate, t-butylcyclohexyl methacrylate, 1-adamantyl methacrylate, and the like. The alkyl methacrylate (a) may be used alone or in combination of 1 or more than 2.

The alkyl methacrylate (a) is preferably an alkyl methacrylate having a linear or branched alkyl group having 1 to 4 carbon atoms or an alkyl methacrylate having an alicyclic structure. Specifically, methyl methacrylate, t-butyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate are preferable.

The content of the structural unit derived from the alkyl methacrylate (a) is 1 to 15 parts by mass based on 100 parts by mass of the total structural units constituting the (meth) acrylic resin (a). When the content of the structural unit derived from the alkyl methacrylate (a) is within the above range, mechanical strength and heat resistance durability tend to be excellent. The content of the structural unit derived from the alkyl methacrylate (a) is preferably 3 parts by mass or more and 13 parts by mass or less, more preferably 4 parts by mass or more and 12 parts by mass or less, and still more preferably 5 parts by mass or more and 11 parts by mass or less, from the viewpoints of mechanical strength and heat resistance and durability. If the amount is within the above range, the mechanical strength is improved by improving the cohesiveness of the adhesive, and the flexibility and adhesiveness of the adhesive can be ensured, which is advantageous in terms of heat resistance and durability.

In the formula (1) representing the hydroxyl group-containing (meth) acrylate (b), examples of the alkyl group represented by A ¹ include an alkyl group having 1to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. Among them, methyl is preferable.

Examples of the substituent optionally included in the methylene group constituting X ¹ in the formula (1) include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), an alkyl group (for example, a C1-10 alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, etc., preferably a C1-6 alkyl group, more preferably a C1-3 alkyl group), a cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), an aryl group (for example, phenyl group, alkylphenyl group (for example, tolyl group, xylyl group, etc.), an aralkyl group (for example, benzyl group), an alkoxy group (for example, an alkoxy group having a C1-4 carbon number such as methoxy group, ethoxy group, etc.), a polyoxyalkylene group (for example, a dioxy group, etc.), a cycloalkoxy group (for example, a C5-10 cycloalkyloxy group such as cyclohexyloxy group, etc.), an aryloxy group (for example, phenoxy group, etc.), an aralkyloxy group (for example, etc.), an alkylthio group (for example, a benzyloxy group, etc.), an alkylthio group (for example, a alkylthio group having a C1-4 carbon number such as methyl group, ethylthio group, etc.), a cycloalkylthio group (for example, a cyclohexylthio group, etc.), an arylthio group (for example, an arylthio group, for example, an acetyl group, etc.), an acetyl group, etc. Among these, a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, and the like are preferable, and an alkyl group (for example, a methyl group, an ethyl group, and the like) is particularly preferable.

In the formula (1), n may be an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 2, for example. When n is 2 or more, X ¹ is optionally the same or different. That is, when n is 2 or more, X ¹ may be constituted by an unsubstituted methylene group, a substituted methylene group, or a substituted methylene group. In the formula (1), when there are 2 or more substituents, the substituents may be the same or different.

Specific examples of the hydroxyl group-containing (meth) acrylic acid ester (b) include 1-hydroxymethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 1-hydroxyheptyl (meth) acrylate, 1-hydroxybutyl (meth) acrylate, 1-hydroxypentyl (meth) acrylate and the like, 1-hydroxyC 1 to C8 alkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxypentyl (meth) acrylate, 2-hydroxyhexyl (meth) acrylate and the like, 2-hydroxyC 2 to C9 alkyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 3-hydroxypentyl (meth) acrylate, 3-hydroxyhexyl (meth) acrylate, 3-hydroxyC 3 to C10 alkyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxypentyl (meth) acrylate, 4-hydroxyhexyl (meth) acrylate, 4-hydroxyheptyl (meth) acrylate and the like 4-hydroxyC 4-C11 alkyl (meth) acrylates such as 4-hydroxyoctyl (meth) acrylate, 2-chloro-2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and the like.

Among these, from the viewpoints of mechanical strength and heat resistance and durability, hydroxyl group-containing (meth) acrylates having n of 2 such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and the like, and hydroxyl group-containing (meth) acrylates having n of 3 such as 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 3-hydroxypentyl (meth) acrylate, and the like are preferable. Particularly preferred are hydroxyl group-containing (meth) acrylates having n of 2, and among these, 2-hydroxyethyl (meth) acrylate is preferred. The 2-hydroxyethyl (meth) acrylate contributes to the formation of a uniform crosslinked structure, and can improve mechanical strength and heat resistance durability.

The hydroxyl group-containing (meth) acrylate (b) may be used alone or in combination of at least 2.

The content of the structural unit derived from the hydroxyl group-containing (meth) acrylate (b) is 0.3 parts by mass or more and 5.5 parts by mass or less with respect to 100 parts by mass of the total structural units constituting the (meth) acrylic resin (a). When the content of the structural unit derived from the alkyl methacrylate (a) is within the above range, mechanical strength and heat resistance durability tend to be excellent. The content of the structural unit derived from the alkyl methacrylate (a) is preferably 0.3 parts by mass or more and 4.0 parts by mass or less, more preferably 0.4 parts by mass or more and 3.0 parts by mass or less, and still more preferably 0.5 parts by mass or more and 2.5 parts by mass or less from the viewpoints of mechanical strength and heat resistance and durability.

Specific examples of the carboxyl group-containing monomer (c) include (meth) acrylic acid, maleic anhydride, fumaric acid, crotonic acid, carboxyalkyl (meth) acrylate (e.g., carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate), and the like. Among them, acrylic acid is preferable. The acrylic acid can promote the reaction of the hydroxyl group-containing (meth) acrylate (b) and the crosslinking agent, is favorable for the formation of a uniform crosslinked structure, and can improve the mechanical strength and the heat resistance durability. The carboxyl group-containing monomer (c) may be used alone or in combination of at least 2.

The content of the structural unit derived from the carboxyl group-containing monomer (c) may be 0.01 parts by mass or more and 5.5 parts by mass or less with respect to 100 parts by mass of the total structural units constituting the (meth) acrylic resin (a), and from the viewpoints of mechanical strength and heat resistance durability, it is preferably 0.05 parts by mass or more and 3 parts by mass or less, more preferably 0.1 parts by mass or more and 2 parts by mass or less.

The mass ratio (c)/(b) [ hereinafter, also referred to as mass ratio (c)/(b) ] of the structural unit derived from the carboxyl group-containing monomer (c) to the structural unit derived from the hydroxyl group-containing (meth) acrylate (b) is 0.06 or more and 1.0 or less. When the mass ratio (c)/(b) is within the above range, the crosslinked structure is uniformly formed in the adhesive, and the mechanical strength and heat resistance durability tend to be excellent. From the viewpoints of mechanical strength and heat resistance and durability, the mass ratio (c)/(b) is preferably 0.06 or more and 0.9 or less, more preferably 0.08 or more and 0.8 or less, still more preferably 0.1 or more and 0.7 or less

The (meth) acrylic resin (a) may further contain a structural unit derived from an alkyl acrylate, a structural unit derived from an alkyl methacrylate having a glass transition temperature (Tg) of less than 30 ℃ of a homopolymer, a structural unit derived from an alkyl (meth) acrylate having a substituent, a structural unit derived from a monomer having a polar functional group other than a hydroxyl group, a structural unit derived from a (meth) acrylamide-based monomer, a structural unit derived from a styrene-based monomer, a structural unit derived from a vinyl-based monomer, a structural unit derived from a monomer having a plurality of (meth) acryloyl groups in a molecule, or the like.

The (meth) acrylic resin (a) preferably contains an alkyl acrylate having a Tg of the homopolymer of less than 0 ℃. Examples of the alkyl acrylate having a Tg of the homopolymer of less than 0℃include ethyl acrylate, n-propyl acrylate and isopropyl acrylate, n-butyl acrylate and isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate and isohexyl acrylate, n-heptyl acrylate, n-octyl acrylate and isooctyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate and isononyl acrylate, n-decyl acrylate and isodecyl acrylate, n-dodecyl acrylate and other linear or branched alkyl acrylates having about 2 to 12 carbon atoms. The alkyl acrylate having Tg of less than 0 ℃ of the homopolymer may be an alkyl acrylate (cycloalkyl acrylate) having an alicyclic structure, but from the viewpoint of follow-up property (or flexibility, adhesiveness) to an optical film, etc., it is preferably an alkyl acrylate having 2 to 10 carbon atoms, preferably an alkyl acrylate having 3 to 8 carbon atoms, and more preferably an alkyl acrylate having 4 to 6 carbon atoms. When these alkyl acrylates are used, the following properties can be improved, and for example, the peeling resistance and the like can be improved. These alkyl acrylates may be used singly or in combination of two or more.

The (meth) acrylic resin (a) preferably contains an alkyl acrylate having a homopolymer Tg of 0 ℃ or higher. Examples of the alkyl acrylate having a homopolymer Tg of 0℃or higher include methyl acrylate, stearyl acrylate, and t-butyl acrylate. The alkyl acrylate having a Tg of 0 ℃ or higher as the homopolymer may be an alkyl acrylate having an alicyclic structure (cycloalkyl acrylate). If these alkyl acrylates are used, the mechanical strength of the adhesive is further improved, which is advantageous in heat resistance and durability. These alkyl acrylates may be used in an amount of 1 or 2 or more. The alicyclic structure may be a cycloalkane structure having usually 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of the alkyl acrylate having a homopolymer with an alicyclic structure with a Tg of 0℃or higher include isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, methylcyclohexyl acrylate, trimethylcyclohexyl acrylate, t-butylcyclohexyl acrylate, and α -ethoxycyclohexyl acrylate.

Examples of the alkyl methacrylate having a Tg of the homopolymer of less than 30℃include n-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate and isohexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate and isooctyl methacrylate, 2-ethylhexyl methacrylate, n-nonyl methacrylate and isononyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate and other linear or branched alkyl methacrylates having about 4 to 12 carbon atoms. These alkyl methacrylates may be used singly or in combination of two or more.

Examples of the alkyl (meth) acrylate having a substituent include alkyl (meth) acrylate having a substituent (the hydrogen atom of the alkyl group is substituted with a substituent) introduced into the alkyl (meth) acrylate. Examples of the substituent include aryl (e.g., phenyl), aryloxy (phenoxy), and alkoxy (e.g., methoxy and ethoxy). Examples of the alkyl acrylate having a substituent include alkoxyalkyl acrylate (e.g., 2-methoxyethyl acrylate, ethoxymethyl acrylate, etc.), aryloxyalkyl acrylate (e.g., phenoxyethyl acrylate, etc.), aryloxypolyalkylene glycol monoacrylate, polyalkylene glycol monoacrylate, etc. These alkyl acrylates may be used singly or in combination of 2 or more. By including an alkyl acrylate containing an aromatic ring such as an aryl group or an aryloxy group, white defects of the polarizing plate in the durability test can be improved (Japanese text: bai). The alkylene group of the aryloxypolyalkylene glycol monoacrylate and the polyalkylene glycol monoacrylate may be, for example, a C1 to C6 alkylene group such as a methylene group, an ethylene group, or a propylene group (preferably, an ethylene group, etc.), and the repeating unit of the oxyalkylene group may be, for example, 2 to 7, preferably 2 to 5 (particularly, 2) from the viewpoint of the durability of the adhesive layer formed of the adhesive composition. Specifically, examples thereof include phenoxy di-to heptaC 1-C3 alkylene glycol acrylates such as phenoxy diethylene glycol acrylate, di-to heptaC 1-C3 alkylene glycol monoacrylate such as diethylene glycol monoacrylate, and the like.

Examples of the monomer having a polar functional group other than a hydroxyl group include (meth) acrylic esters having a substituent such as a heterocyclic group such as a substituted or unsubstituted amino group or an epoxy group. Specifically, monomers having a heterocyclic group such as acryloylmorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, and 2, 5-dihydrofuran, monomers having a substituted or unsubstituted amino group such as aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, and dimethylaminopropyl (meth) acrylate, and the like are exemplified. These monomers may be used singly or in combination of two or more. From the viewpoint of preventing the separator that can be laminated on the pressure-sensitive adhesive layer from deteriorating in peelability, it is preferable that the separator contains substantially no structural unit derived from a monomer having an amino group. The substantial absence of the component (b) means that the component (b) is less than 1.0 part by mass per 100 parts by mass of the total constituent units constituting the (meth) acrylic resin (a).

Examples of the (meth) acrylamide monomer include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide, N- (5-hydroxypentyl) (meth) acrylamide, N- (6-hydroxyhexyl) (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- (3-dimethylaminopropyl) (meth) acrylamide, N- (1, 1-dimethyl-3-oxobutyl) (meth) acrylamide, N- [2- (2-oxo-1-imidazolidinyl) ethyl ] (meth) acrylamide, 2- (meth) acrylamido-2-methyl-1-propanesulfonic acid, N- (methoxymethyl) (meth) acrylamide, N- (ethoxymethyl) (meth) acrylamide, N- (propoxymethyl) (meth) acrylamide, N- (1-methylethoxymethyl) (meth) acrylamide, N- (1-methylpropoxy methyl) (meth) acrylamide, N- (2-methylpropoxy methyl) (meth) acrylamide [ alias: N- (isobutoxy methyl) (meth) acrylamide ], N- (butoxymethyl) (meth) acrylamide, N- (1, 1-dimethylethoxymethyl) (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N- (2-ethoxyethyl) (meth) acrylamide, N- (2-propoxyethyl) (meth) acrylamide, N- [2- (1-methylethoxy) ethyl ] (meth) acrylamide, N- [2- (1-methylpropoxy) ethyl ] (meth) acrylamide, N- [2- (2-methylpropoxy) ethyl ] (meth) acrylamide [ alias: N- (2-isobutoxy ethyl) (meth) acrylamide ], N- (2-butoxyethyl) (meth) acrylamide, N- [2- (1, 1-dimethylethoxy) ethyl ] (meth) acrylamide, and the like. The structural units derived from the (meth) acrylamide monomer may be used in an amount of 1 or 2 or more.

Examples of the styrene monomer include alkylstyrenes such as styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene, halostyrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene and iodostyrene, nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene and the like.

Examples of the vinyl monomer include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate, vinyl halides such as vinyl chloride and vinyl bromide, vinylidene halides such as vinylidene chloride, nitrogen-containing aromatic vinyl such as vinylpyridine, vinylpyrrolidone and vinylcarbazole, and conjugated diene monomers such as butadiene, isoprene and chloroprene.

Examples of the monomer having a plurality of (meth) acryloyl groups in the molecule include monomers having 2 (meth) acryloyl groups in the molecule such as 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and monomers having 3 (meth) acryloyl groups in the molecule such as trimethylolpropane tri (meth) acrylate.

The weight average molecular weight (Mw) of the (meth) acrylic resin (A) is preferably 100 to 320 tens of thousands, more preferably 110 to 310 tens of thousands, still more preferably 120 to 300 tens of thousands, particularly preferably 130 to 290 tens of thousands, from the viewpoints of mechanical strength and heat resistance and durability. The molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually 1.5 or more and 10 or less, preferably 2 or more and 8 or less, and more preferably 2.5 or more and 7 or less. The weight average molecular weight can be analyzed by gel permeation chromatography, which is a standard polystyrene-equivalent value.

From the viewpoints of mechanical strength and heat resistance and durability, the glass transition temperature (Tg) of the (meth) acrylic resin (a) is preferably from-45 ℃ to-10 ℃, more preferably from-40 ℃ to-15 ℃, and even more preferably from-38 ℃ to-20 ℃.

The (meth) acrylic resin (a) (in the case of combining 2 or more, a mixture thereof) is dissolved in ethyl acetate, and a solution having a concentration of 20 mass% is preferably a solution having a viscosity of 20pa·s or less at 25 ℃, more preferably a solution having a viscosity of 0.1pa·s or more and 7pa·s or less. The viscosity can be determined by a Brookfield viscometer (Brookfield viscometer).

The (meth) acrylic resin (a) can be produced by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method. A polymerization initiator is generally used for producing the (meth) acrylic resin (a). The polymerization initiator is used in an amount of about 0.001 to 5 parts by mass based on 100 parts by mass of the total of all monomers used for producing the (meth) acrylic resin (A). The (meth) acrylic resin (a) may be produced by a method of advancing polymerization by an active energy ray such as ultraviolet ray.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like can be used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone and the like. Examples of the thermal polymerization initiator include azo compounds such as 2,2' -azobisisobutyronitrile, 2' -azobis (2-methylbutyronitrile), 1' -azobis (cyclohexane-1-carbonitrile), 2' -azobis (2, 4-dimethylvaleronitrile), 2' -azobis (2, 4-dimethyl-4-methoxyvaleronitrile), dimethyl-2, 2' -azobis (2-methylpropionate), and 2,2' -azobis (2-hydroxymethylpropionitrile); organic peroxides such as lauryl peroxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, (3, 5-trimethylhexanoyl) peroxide, inorganic peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide, and the like. Further, a redox initiator or the like using a peroxide in combination with a reducing agent may be used as the polymerization initiator.

As a method for producing the (meth) acrylic resin (a), the solution polymerization method is preferable among the methods described above. An example of the solution polymerization method is to mix a monomer and an organic solvent, add a thermal polymerization initiator under a nitrogen atmosphere, and stir at about 40 to 90 ℃, preferably about 60 to 80 ℃ for about 3 to 10 hours. In order to control the reaction, the monomer, the thermal polymerization initiator, or the solvent may be added continuously or intermittently in the polymerization, or in a state of being dissolved in an organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, aliphatic alcohols such as propanol and isopropanol, and ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone.

(2) Crosslinking agent (B)

The adhesive composition further contains a crosslinking agent (B). The crosslinking agent (B) may be a compound which reacts with a structural unit derived in particular from a monomer having a polar functional group in the (meth) acrylic resin (a) and crosslinks the (meth) acrylic resin (a). Specifically, isocyanate compounds, epoxy compounds, aziridine (aziridine) compounds, metal chelate compounds, and the like can be exemplified. Among these, the isocyanate compound, the epoxy compound, and the aziridine compound have at least 2 functional groups within the molecule that can react with polar functional groups in the (meth) acrylic resin. The crosslinking agent (B) may be used alone or in combination of at least 2 kinds.

The isocyanate compound is preferably a compound having at least 2 isocyanate groups (-NCO) in the molecule, and examples thereof include aliphatic isocyanate compounds (for example, hexamethylene diisocyanate and the like), alicyclic isocyanate compounds (for example, isophorone diisocyanate), aromatic isocyanate compounds (for example, toluene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate and the like) and the like. The crosslinking agent (B) may be a derivative of an isocyanate compound such as a urethane prepolymer type isocyanate compound obtained by an addition reaction of an adduct (Adduct) of an isocyanate compound with a polyol compound (for example, an adduct of glycerin, trimethylolpropane, or the like), an isocyanurate, a biuret type compound, a polyether polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, or a polyisoprene polyol. The crosslinking agent (B) may be used singly or in combination of two or more. Of these, typical examples include aromatic isocyanate compounds (e.g., toluene diisocyanate and xylylene diisocyanate), aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), and adducts of these based on polyol compounds (glycerol and trimethylolpropane). When the crosslinking agent (B) contains an aromatic isocyanate compound and/or an adduct of these compounds based on a polyol compound, a uniform crosslinked structure tends to be formed easily, and mechanical strength and heat resistance durability tend to be improved easily.

The epoxy compound is a compound having at least 2 epoxy groups in the molecule. Specific examples of the compound include bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol triglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, N, N-diglycidyl aniline, N, N, N ', N ' -tetraglycidyl m-xylylenediamine, 1, 3-bis (N, N ' -diglycidyl aminomethyl) cyclohexane, and the like. More than 2 epoxy compounds may be mixed and used.

Aziridine-based compounds, also called ethyleneimines, are compounds having a 3-membered ring skeleton of at least 2 nitrogen atoms and 2 carbon atoms in the molecule. Specific examples of the compound include diphenylmethane-4, 4' -bis (1-aziridine carboxamide), toluene-2, 4-bis (1-aziridine carboxamide), triethylenemelamine, isophthaloyl bis-1- (2-methylaziridine), tris-1-aziridinyl phosphine oxide, hexamethylene-1, 6-bis (1-aziridine carboxamide), trimethylol propane-tris- β -aziridinyl propionate, and tetramethylol methane-tris- β -aziridinyl propionate.

Examples of the metal chelate compound include compounds in which acetylacetone and ethyl acetoacetate are coordinated to polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium.

Among them, isocyanate-based compounds are preferable, and aromatic isocyanate-based compounds such as toluene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate and the like, and adducts (Adduct) thereof based on polyol compounds (for example, glycerol, trimethylolpropane and the like) are more preferable.

The crosslinking agent (B) is usually blended in a ratio of 0.01 to 5 parts by mass, based on 100 parts by mass of the solid content of the (meth) acrylic resin (a) (when 2 or more types are used, the total of these types is used), and is preferably 0.05 to 2 parts by mass from the viewpoints of mechanical strength and heat resistance and durability.

(3) Silane compound (C)

The adhesive composition contains a silane compound (C). By containing the silane compound (C), adhesion (or adhesiveness) between the pressure-sensitive adhesive layer and the metal layer, transparent electrode, glass substrate, or the like can be improved. Examples of the silane compound (C) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl ethoxydimethylsilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, 1, 3-bis (3' -trimethoxypropyl) urea, 1, 6-bis (trimethoxysilyl) hexane, and 1, 8-bis (trimethoxysilyl) octane.

The silane compound may be an organosilicon oligomer. Specific examples of the silicone oligomer are shown below. In the following specific examples, the silicone oligomer is described as a combination of monomers.

3-Mercaptopropyl trimethoxysilane tetramethoxysilane oligomer,

3-Mercaptopropyl trimethoxysilane tetraethoxysilane oligomer,

3-Mercaptopropyl triethoxysilane tetramethoxysilane oligomer,

Mercaptopropyl-containing oligomers such as 3-mercaptopropyl triethoxysilane-tetraethoxysilane oligomers;

Mercapto methyl trimethoxy silane-tetramethoxy silane oligomer,

Mercapto methyl trimethoxy silane-tetraethoxy silane oligomer,

Mercaptomethyltriethoxysilane tetramethoxysilane oligomer,

Mercaptomethyl-containing oligomers such as mercaptomethyl triethoxysilane-tetraethoxysilane oligomers;

3-methacryloyloxy propyl trimethoxy silane-tetramethoxy group silane oligomer,

3-Methacryloyloxy propyl trimethoxy silane-tetraethoxy silane oligomer,

3-Methacryloyloxy propyl triethoxy silane-tetramethoxy group silane oligomer,

3-Methacryloyloxy propyl triethoxy silane-tetraethoxy silane oligomer,

3-Methacryloxypropyl methyl dimethoxy silane-tetramethoxy silane oligomer,

3-Methacryloxypropyl methyl Di-methoxysilane-tetraethoxy silane oligomer,

3-Methacryloxypropyl methyl Di-ethoxysilane-tetramethoxy group silane oligomer,

3-Methacryloxypropyl methyl radical diethoxysilane-tetraethoxy methacryloxypropyl-containing oligomers such as silane oligomers;

3-acryloyloxy propyl trimethoxy silane-tetramethoxy group silane oligomer,

3-Acryloyloxy propyl trimethoxy silane-tetraethoxy silane oligomer,

3-Acryloyloxy propyl triethoxy silane-tetramethoxy group silane oligomer,

3-Acryloyloxy propyl triethoxy silane-tetraethoxy silane oligomer,

3-Acryloxypropyl methyl dimethoxy silane-tetramethoxy silane oligomer,

3-Acryloxypropyl methyl dimethoxy silane-tetraethoxy silane oligomer,

3-Acryloxypropyl methyl diethoxy silane-tetramethoxy silane oligomer,

Acryloxypropyl group-containing oligomers such as 3-acryloxypropyl methyldiethoxysilane-tetraethoxysilane oligomers;

vinyl trimethoxy silane-tetramethoxy silane oligomer,

Vinyl trimethoxy silane-tetraethoxy silane oligomer,

Vinyl triethoxysilane-tetraethoxy silane methoxy silane oligomer,

Vinyl triethoxysilane-tetraethoxy silane ethoxysilane oligomer,

Vinyl methyl dimethoxy silane-tetramethoxy silane oligomer,

Vinyl methyl dimethoxy silane-tetraethoxy silane oligomer,

Vinyl methyl diethoxy silane-tetramethoxy silane oligomer,

Vinyl-containing oligomers such as vinylmethyldiethoxysilane-tetraethoxysilane oligomers.

The silane compound (C) is preferably a silane compound represented by the formula (C).

[ Chemical formula 3]

By containing the silane compound (C), adhesion to metals, transparent electrodes, glass substrates, and the like tends to be improved, and heat resistance and durability tend to be excellent. In the above formula (C), A ¹、A² and A ³ independently represent an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include methyl, ethyl, n-propyl and isopropyl groups, and examples of the alkoxy group having 1 to 3 carbon atoms include methoxy, ethoxy, n-propoxy and isopropoxy groups.

In the formula (C), L represents an alkylene group having 8 to 12 carbon atoms, or represents a group in which at least 1 methylene group constituting the alkylene group is replaced with a group selected from-NH-and-O-. Examples of the alkylene group having 8 to 12 carbon atoms include -(CH₂)₈-、-(CH₂)₉-、-(CH₂)₁₀-、-(CH₂)₁₁-、-(CH₂)₁₂-.

In the case where L is a group in which at least 1 methylene group constituting an alkylene group having 8 to 12 carbon atoms is replaced with a group selected from the group consisting of-NH-and-O-, it is possible that only 1 methylene group is replaced by-NH-or-O-, it is also possible that more than 2 methylene groups are each replaced by-NH-or-O-. In the case where more than 2 methylene groups are substituted, typically, 2 or more of the substituted-NH-and/or-O-groups are bonded through an alkylene group having 2 or more carbon atoms.

In the formula (C), X represents a thiol group (-SH), an epoxy group represented by the following formula, an amino group (-NH ₂), or an alicyclic epoxy group.

[ Chemical formula 4]

Examples of the alicyclic epoxy group include a 1-valent group having 1 hydrogen atom removed from the structure represented by the following formula.

[ Chemical formula 5]

(Wherein n represents an integer of 1 to 5.)

Among them, the silane compound (C) is preferably one wherein A ¹、A² and A ³ are methoxy or ethoxy and X is a thiol group, epoxy group or amino group independently of each other, and more preferably one comprising or consisting of the silane compound (C-1) represented by the formula (C-1).

[ Chemical formula 6]

In the above formula (C-1), m represents an integer of 6 to 10.

If a specific example of the silane compound (C-1) is given, for example:

6-epoxypropoxyhexyl radical trimethoxysilane (III),

7-Epoxypropoxy hept a methyltrimethoxysilane,

8-Glycidoxy octyl trimethoxy silane,

9-Epoxypropoxy nonane a methyltrimethoxysilane,

10-Glycidoxy decyl trimethoxy silane. The silane compound (C-1) is mostly a liquid. As the silane compound (C-1), commercially available ones may be used, or silane compounds produced by a known method may be used.

The content of the silane compound (C) in the adhesive composition is usually 0.01 to 5 parts by mass, preferably 0.1 to 4 parts by mass, more preferably 0.2 to 3 parts by mass, based on 100 parts by mass of the solid content of the (meth) acrylic resin (a) (when 2 or more types are used, the total of these types). If the upper limit value is less than or equal to the upper limit value, bleeding of the silane compound (C) from the pressure-sensitive adhesive layer is favorably suppressed, and if the lower limit value is more than or equal to the lower limit value, adhesion (or adhesiveness) between the pressure-sensitive adhesive layer and a metal layer, a glass substrate, or the like is easily improved, and peeling resistance or the like is favorably improved.

[ Ionic Compound ]

The adhesive composition may further contain an ionic compound. The ionic compound may function as an antistatic agent for imparting antistatic properties to the adhesive layer. The ionic compound is a compound having an inorganic cation or an organic cation and an inorganic anion or an organic anion.

Examples of the inorganic cations include alkali metal ions such as lithium cations [ Li ⁺ ], sodium cations [ Na ⁺ ] and potassium cations [ K ⁺ ], alkaline earth metal ions such as beryllium cations [ Be ²⁺ ], magnesium cations [ Mg ²⁺ ] and calcium cations [ Ca ²⁺ ].

Examples of the organic cation include an imidazolium cation, a pyridinium cation, a pyrrolidinium cation, an ammonium cation, a sulfonium cation, and a phosphonium cation.

Among the above cationic components, the organic cationic component is preferably used because of its excellent compatibility with the adhesive composition. Among the organic cation components, pyridinium cations and imidazolium cations are preferably used, in particular, from the viewpoint of being less likely to be charged when the release film provided on the pressure-sensitive adhesive layer is peeled off.

Examples of the inorganic anions include chloride [ Cl ^- ], bromide [ Br ^- ], iodide [ I ^- ], tetrachloroaluminate [ AlCl ₄ ^- ], and the like, Heptachlorodialuminate anion [ Al ₂Cl₇ ^- ], tetrafluoroborate anion [ BF ₄ ^- ], hexafluorophosphate anion [ PF ₆ ^- ] Perchlorate anions [ ClO ₄ ^- ], nitrate anions [ NO ₃ ^- ], hexafluoroarsenate anions [ AsF ₆ ^- ], Hexafluoroantimonate anion [ SbF ₆ ^- ], hexafluoroniobate anion [ NbF ₆ ^- ] Hexafluorotantalate anions [ TaF ₆ ^- ], dicyanoimine anions [ (CN) ₂N^- ], and the like.

Examples of the organic anions include acetate anions [ CH ₃COO^- ], trifluoroacetate anions [ CF ₃COO^- ], methanesulfonate anions [ CH ₃SO₃ ^- ], trifluoromethanesulfonate anions [ CF ₃SO₃ ^- ], and combinations thereof, P-toluenesulfonate anion [ p-CH ₃C₆H₄SO₃ ^- ], bis (fluorosulfonyl) imide anion [ (FSO ₂)₂N^- ], bis (trifluoromethylsulfonyl) imide anion [ (CF ₃SO₂)₂N^- ], tris (trifluoromethylsulfonyl) methanation anion [ (CF ₃SO₂)₃C^- ] Dimethyl phosphonate anions [ (CH ₃)₂POO^- ], (poly) hydrofluoride anions [ F (HF) _n ^- ] (n is about 1 to 3), thiocyanate anions [ SCN ^- ] Perfluorobutanesulfonate anion [ C ₄F₉SO₃ ^- ], bis (pentafluoroethanesulfonyl) imide anion [ (C ₂F₅SO₂)₂N^- ], perfluorobutanoate anion [ C ₃F₇COO^- ], (trifluoromethanesulfonyl) (trifluoromethanecarbonyl) imide anion [ (CF ₃SO₂)(CF₃CO)N^- ] Perfluoropropane-1, 3-disulfonate anion [ ^-O₃S(CF₂)₃SO₃ ^- ], carbonate anion [ CO ₃ ^2- ], and the like.

Among the above-mentioned anionic components, particularly an anionic component containing a fluorine atom can form an ionic compound excellent in antistatic performance, and thus is preferably used. Examples of the anionic component containing a fluorine atom include a bis (fluorosulfonyl) imide anion, a hexafluorophosphate anion, and a bis (trifluoromethanesulfonyl) imide anion.

Specific examples of the ionic compound may be appropriately selected from the combinations of the above cationic component and anionic component. Examples of the ionic compounds having an organic cation include the following compounds if classified and revealed according to the structure of the organic cation.

Pyridinium salts:

hexafluorophosphoric acid N-hexyl pyridinium,

N-octyl pyridinium hexafluorophosphate,

N-octyl-4-methylpyridinium hexafluorophosphate,

N-butyl-4-methylpyridinium hexafluorophosphate,

Tetrabutylammonium hexafluorophosphate,

N-decylpyridinium bis (fluorosulfonyl) imide,

N-dodecylpyridinium bis (fluorosulfonyl) imide,

N-tetradecylpyridinium bis (fluorosulfonyl) imide,

N-cetyl pyridinium bis (fluorosulfonyl) imide,

N-dodecyl-4-methylpyridinium bis (fluorosulfonyl) imide,

N-tetradecyl-4-methylpyridinium bis (fluorosulfonyl) imide,

N-hexadecyl-4-methylpyridinium bis (fluorosulfonyl) imide,

N-benzyl-2-methylpyridinium bis (fluorosulfonyl) imide,

N-benzyl-4-methylpyridinium bis (fluorosulfonyl) imide,

N-hexylpyridinium bis (trifluoromethanesulfonyl) imide,

N-octyl pyridinium bis (trifluoromethanesulfonyl) imide,

N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,

N-butyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imine.

Imidazolium salts:

1-ethyl-3-methylimidazolium hexafluorophosphate,

1-Ethyl-3-methylimidazolium p-toluenesulfonate,

1-Ethyl-3-methylimidazolium bis (fluorosulfonyl) imide,

1-Ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide,

1-Butyl-3-methylimidazolium mesylate,

1-Butyl-3-methylimidazolium bis (fluorosulfonyl) imide.

Pyrrolidinium salts:

N-butyl-N-methylpyrrolidinium hexafluorophosphate,

N-butyl-N-methylpyrrolidinium bis (fluorosulfonyl) imide,

N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide.

Quaternary ammonium salt:

tetrabutylammonium p-toluenesulfonate,

(2-Hydroxyethyl) trimethylammonium bis (trifluoromethanesulfonyl) imine,

Dimethyl phosphinic acid (2-hydroxyethyl) trimethylammonium,

Tributyl methyl ammonium bis (trifluoromethanesulfonyl) imide,

Trimethyl propyl ammonium bis (trifluoromethanesulfonyl) imine,

Methyl tri-n-octylammonium bis (trifluoromethanesulfonyl) imide.

In addition, the following compounds are examples of ionic compounds having an inorganic cation.

Lithium bromide,

Lithium iodide,

Lithium tetrafluoroborate,

Lithium hexafluorophosphate,

Lithium thiocyanate,

Lithium perchlorate,

Lithium triflate,

Lithium bis (fluorosulfonyl) imide,

Lithium bis (trifluoromethanesulfonyl) imide,

Lithium bis (pentafluoroethylsulfonyl) imide,

Lithium tris (trifluoromethanesulfonyl) methanation,

Lithium p-toluenesulfonate,

Sodium hexafluorophosphate,

Sodium bis (fluorosulfonyl) imide,

Sodium bis (trifluoromethanesulfonyl) imide,

Sodium p-toluenesulfonate,

Potassium hexafluorophosphate,

Potassium bis (fluorosulfonyl) imide,

Potassium bis (trifluoromethanesulfonyl) imide,

Potassium p-toluenesulfonate.

The ionic compound is preferably solid at room temperature. The antistatic performance can be maintained for a long period of time as compared with the case of using an ionic compound which is liquid at ordinary temperature. From the viewpoint of long-term stability of such antistatic properties, the ionic compound preferably has a melting point of 25 ℃ or higher. On the other hand, if the melting point is too high, the compatibility with the (meth) acrylic resin (a) is deteriorated, and therefore the melting point is preferably 90 ℃ or less, more preferably 70 ℃ or less, and still more preferably less than 50 ℃.

The content of the ionic compound in the adhesive composition is usually 0.2 parts by mass or more and 10 parts by mass or less, preferably 0.2 parts by mass or more and 9 parts by mass or less, more preferably 0.5 parts by mass or more and 8 parts by mass or less, per 100 parts by mass of the solid content of the (meth) acrylic resin (a) (when 2 or more are used, the total of these components). If the amount is within the above range, the ionic compound is less likely to aggregate in the binder, and the heat resistance and durability can be improved.

[ Other Components ]

The adhesive composition may contain additives such as solvents, crosslinking catalysts, ultraviolet absorbers, weather stabilizers, tackifiers (tackifier), plasticizers, softeners, dyes, pigments, inorganic fillers, light scattering fine particles, rust inhibitors, release agents, resins other than the (meth) acrylic resin (a), and the like. Further, it is also useful to prepare a harder adhesive layer by mixing an ultraviolet-curable compound with the adhesive composition to form an adhesive layer and then irradiating the adhesive layer with ultraviolet rays to cure the adhesive layer. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin and melamine resin.

When the adhesive composition contains the crosslinking agent (B) and the crosslinking catalyst, the adhesive layer can be prepared by curing in a short period of time. In addition, if the crosslinking catalyst is contained, swelling, peeling, foaming of the adhesive layer at the interface between the adhesive layer and the member adjacent thereto can be more effectively suppressed, and reworkability (reworkability) becomes more excellent. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin and melamine resin. When the adhesive composition contains an amine compound as a crosslinking catalyst, an isocyanate compound is suitable as the crosslinking agent (B).

The adhesive composition may be prepared by mixing the above ingredients. The gel fraction of the adhesive composition may be, for example, 50% to 98%, preferably 60% to 95%. Gel fraction can be measured according to the measurement method in the column of examples described later.

< Adhesive layer >

(1) First embodiment

The adhesive layer according to the first embodiment of the present invention [ hereinafter, also referred to as an adhesive layer (1) ] contains the above-described adhesive composition of the present invention, and is typically composed of the adhesive composition of the present invention. The adhesive layer (1) can be obtained by dissolving or dispersing each component constituting the adhesive composition in a solvent to form an adhesive composition containing the solvent, then applying the adhesive composition to a substrate film, and drying the substrate film. The adhesive layer (1) is excellent in mechanical strength and heat resistance durability.

The base film is generally a plastic film, and a typical example thereof is a release film (separator) subjected to a release treatment. The release film may be, for example, a film obtained by subjecting the pressure-sensitive adhesive layer-forming surface of a film formed of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarylate to a release treatment such as silicone treatment. The pressure-sensitive adhesive composition may be directly applied to the surface of the optical film to form a pressure-sensitive adhesive layer, and if necessary, a release film may be laminated on the outer surface of the pressure-sensitive adhesive layer to form an optical film with a pressure-sensitive adhesive layer. When the adhesive layer is provided on the surface of the optical film, a surface activation treatment, for example, a plasma treatment, a corona treatment, or the like may be performed on the bonding surface of the optical film and/or the bonding surface of the adhesive layer, as required.

The thickness of the pressure-sensitive adhesive layer (1) may be, for example, 10 μm or more and 50 μm or less, and is preferably 15 μm or more and 40 μm or less, more preferably 18 μm or more and 35 μm or less from the viewpoints of mechanical strength and heat resistance and durability.

From the viewpoints of mechanical strength and heat resistance and durability, the pressure-sensitive adhesive layer (1) preferably has a fracture energy per unit volume of 1.2X10 ⁶J/m³ or more, more preferably 1.4X10 ⁶J/m³ or more, still more preferably 1.7X10 ⁶J/m³ or more, particularly preferably 2.0X10 ⁶J/m³ or more, and usually 5.0X10 ⁶J/m³ or less. The energy of rupture per unit volume can be determined according to the method described in the columns of the examples described below.

(2) Second embodiment

The pressure-sensitive adhesive layer according to the second embodiment of the present invention [ hereinafter, also referred to as pressure-sensitive adhesive layer (2) ] is a pressure-sensitive adhesive layer having a rupture energy per unit volume of 1.2X10 ⁶J/m³ or more. The pressure-sensitive adhesive layer (2) tends to have excellent mechanical strength and heat resistance durability by the fracture energy per unit volume falling within the above range. From the viewpoints of mechanical strength and heat resistance and durability, the fracture energy per unit volume of the pressure-sensitive adhesive layer (2) is preferably 1.4X10 ⁶J/m³ or more, more preferably 1.7X10 ⁶J/m³ or more, still more preferably 2.0X10 ⁶J/m³ or more, and usually 5.0X10 ⁶J/m³ or less.

The adhesive layer (2) may be formed of an adhesive composition. The above description of the adhesive composition is applicable to the adhesive composition constituting the adhesive layer (2). The thickness of the adhesive layer (2) and the method of forming the same are applicable to the description of the adhesive layer (1).

< Optical film with adhesive layer >

The optical film with an adhesive layer of the present invention may include, for example, an optical film and the above-described adhesive layer laminated thereon.

Examples of the optical film include a polarizing plate, a protective film provided for protecting the surface of the polarizing plate, a polarizing plate having a protective film laminated on one or both surfaces of the polarizing plate, a retardation film, an optical compensation film other than the retardation film, a film having an antiglare function on the surface thereof, a film having an antireflection function on the surface thereof, a reflective film having a reflection function on the surface thereof, a semi-transmissive reflective film having both a reflection function and a transmission function, a light diffusion film, and a hard coat film. The optical film with the adhesive layer may contain 1 or 2 or more kinds of optical films, or may contain 2 or more kinds of optical films of the same kind. When the optical film includes 2 or more optical films, a bonding layer described later may be used to laminate 2 or more optical films, and in this case, the bonding layer may be a part of the optical films. The thickness of the optical film is not particularly limited, and may be, for example, 5 μm to 300 μm. In this specification, a polarizing plate in which a protective film is laminated on one or both surfaces of a polarizing plate is also referred to as a linear polarizing plate.

Examples of the polarizer include a polarizer in which iodine is aligned with a polyvinyl alcohol resin layer, a polarizer in which a liquid crystal compound and a dichroic dye are aligned, and the like.

The protective film is not particularly limited, but is preferably a thermoplastic resin film having light transmittance (preferably optical transparency). Examples of the thermoplastic resin constituting such a film include polyolefin resins such as chain polyolefin resins (polyethylene resins, polypropylene resins, etc.), cyclic polyolefin resins (norbornene resins, etc.), cellulose ester resins such as triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate resins, (meth) acrylic resins such as (meth) acrylic acid and polymethyl (meth) acrylate, vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate, polystyrene resins, and mixtures and copolymers of these resins. In the present specification, "meth) acrylic" means "at least 1 kind of acrylic and methacrylic". These resins may contain 1 or 2 or more additives such as lubricants, plasticizers, dispersants, heat stabilizers, ultraviolet absorbers, infrared absorbers, antistatic agents, antioxidants, and light diffusers such as fine particles.

The chain polyolefin resin includes, in addition to homopolymers of chain olefins such as polyethylene resins and polypropylene resins, copolymers of 2 or more chain olefins.

The cyclic polyolefin resin is a generic term for a resin obtained by polymerizing a cyclic olefin as a polymerization unit. Examples of the cyclic polyolefin resin include a ring-opened (co) polymer of a cyclic olefin, an addition polymer of a cyclic olefin, a copolymer (typically a random copolymer) of a cyclic olefin and a chain olefin such as ethylene or propylene, a graft polymer obtained by modifying the copolymer with an unsaturated carboxylic acid or a derivative thereof, and a hydrogenated product of the copolymer. Among them, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.

The cellulose resin is a partially or completely esterified product of cellulose, and examples thereof include cellulose acetate, cellulose propionate, cellulose butyrate, and mixed esters thereof. Among them, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like are preferably used.

The polyester resin is a resin other than the cellulose resin described above, which has an ester bond, and is generally a resin formed of a polycondensate of a polycarboxylic acid or a derivative thereof and a polyhydric alcohol. As the polycarboxylic acid or derivative thereof, a dicarboxylic acid or derivative thereof may be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl naphthalate and the like. As the polyhydric alcohol, there may be used a glycol, for example, ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, cyclohexanedimethanol, and the like.

Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate poly (trimethylene terephthalate), poly (trimethylene naphthalate), poly (cyclohexanedimethylene terephthalate), and poly (cyclohexanedimethylene naphthalate).

The polycarbonate resin includes a polymer in which monomer units are bonded via carbonate groups. The polycarbonate resin may be a resin called a modified polycarbonate, a copolymerized polycarbonate, or the like, in which a polymer skeleton is modified.

The (meth) acrylic resin may be a polymer of a methacrylate-based monomer, preferably a copolymer in which a small amount of other comonomer components is copolymerized. The (meth) acrylic resin is more preferably a copolymer of methyl methacrylate and methyl acrylate, and the third monofunctional monomer may be further copolymerized.

Examples of the third monofunctional monomer include methacrylates other than methyl methacrylate, such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate, acrylates, such as ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate, hydroxyalkylacrylates, such as methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and butyl 2- (hydroxymethyl) acrylate, unsaturated acids, such as methacrylic acid and acrylic acid, substituted styrenes, such as chlorostyrene and bromostyrene, unsaturated nitriles, such as vinyltoluene and α -methylstyrene, unsaturated nitriles, such as acrylonitrile and methacrylonitrile, unsaturated anhydrides, such as maleic anhydride and maleic anhydride, and unsaturated imides, such as phenylmaleimide and cyclohexylmaleimide. The third monofunctional monomer may be used alone or in combination of 2 or more.

The (meth) acrylic resin may further comprise a polyfunctional monomer. Examples of the polyfunctional monomer include monomers such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, tetradecanediol di (meth) acrylate and the like in which both terminal hydroxyl groups of ethylene glycol or an oligomer thereof are esterified with acrylic acid or methacrylic acid, monomers in which both terminal hydroxyl groups of propylene glycol or an oligomer thereof are esterified with acrylic acid or methacrylic acid, monomers such as neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate and butanediol di (meth) acrylate in which hydroxyl groups of a dihydric alcohol are esterified with acrylic acid or methacrylic acid, alkylene oxide adducts of bisphenol A, or monomers in which both terminal hydroxyl groups of a halogen substituent such as acrylic acid or methacrylic acid are esterified, monomers in which a polyhydric alcohol such as trimethylolpropane or pentaerythritol is esterified with acrylic acid or methacrylic acid, and monomers in which epoxy groups of a terminal hydroxyl group of a glycidyl acrylate or a glycidyl methacrylate are ring-opened, and aromatic vinyl ester, such as succinic acid, a glycidyl ester or a glycidyl ester of a hydroxy group of a diol, and the like, and aromatic vinyl ester of a glycidyl ester or a glycidyl ester of a dicarboxylic acid. Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, neopentyl glycol dimethacrylate are preferably used.

The (meth) acrylic resin may be a resin modified by further reacting functional groups of the copolymer with each other. Examples of the reaction include a intramolecular demethylating condensation reaction between a methyl ester group of methyl acrylate and a hydroxyl group of methyl 2- (hydroxymethyl) acrylate, and a intramolecular dehydrating condensation reaction between a carboxyl group of acrylic acid and a hydroxyl group of methyl 2- (hydroxymethyl) acrylate. The (meth) acrylic resin may have any one of a glutarimide derivative, and a lactone ring structure.

The glass transition temperature of the (meth) acrylic resin is preferably 90 to 160 ℃, more preferably 110 to 160 ℃, and even more preferably 120 to 150 ℃.

The (meth) acrylic resin may contain additives as required. Examples of the additives include lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light-resistant agents, impact modifiers, and surfactants.

From the viewpoints of film formability to a film, impact resistance of a film, and the like, the (meth) acrylic resin may contain acrylic rubber particles as an impact modifier. The acrylic rubber particles are particles containing an elastic polymer mainly composed of an acrylic ester as an essential component, and examples thereof include particles having a single-layer structure substantially composed of only the elastic polymer, and particles having a multilayer structure in which the elastic polymer is used as one layer. Examples of the elastic polymer include crosslinked elastic copolymers comprising an alkyl acrylate as a main component and copolymerized with the alkyl acrylate, another vinyl monomer copolymerizable with the alkyl acrylate and a crosslinkable monomer. Examples of the alkyl acrylate which is the main component of the elastic polymer include alkyl acrylates having about 1 to 8 alkyl groups such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate, and acrylic acid having an alkyl group having 4 or more carbon atoms is particularly preferably used. Examples of the other vinyl monomer copolymerizable with the alkyl acrylate include compounds having 1 polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylates such as methyl methacrylate, aromatic vinyl compounds such as styrene, vinyl cyanide compounds such as acrylonitrile, and the like. Examples of the crosslinkable monomer include crosslinkable compounds having at least 2 polymerizable carbon-carbon double bonds in the molecule, more specifically, (meth) acrylic esters of polyhydric alcohols such as ethylene glycol di (meth) acrylate and butanediol di (meth) acrylate, (meth) acrylic acid vinyl esters such as allyl (meth) acrylate, divinylbenzene, and the like.

A laminate of a film formed of an acrylic resin containing no rubber particles and a film formed of an acrylic resin containing rubber particles may be used as the protective film.

The retardation film is an optical film exhibiting optical anisotropy, and may be a stretched film obtained by stretching a resin film formed of a resin usable for the protective film, other than the resin usable for the protective film, such as a polyvinyl alcohol resin, a polyarylate resin, a polyimide resin, a polyether sulfone resin, a polyvinylidene fluoride/polymethyl methacrylate resin, a liquid crystal polyester resin, an ethylene-vinyl acetate copolymer saponified product, a polyvinyl chloride resin, or the like, to about 1.01 to 6 times. Among them, a stretched film obtained by uniaxially stretching or biaxially stretching a polycarbonate resin film, a cycloolefin resin film, a (meth) acrylic resin film or a cellulose resin film is preferable. In addition, in this specification, a zero-retardation film is also included in the phase difference film (however, it may also be used as a protective film). Films called uniaxial retardation film, wide viewing angle retardation film, low photoelastic modulus retardation film, and the like are also applicable as retardation films.

The retardation film may be a film having an optically anisotropic layer formed of a polymer polymerized in a state where a polymerizable liquid crystal compound is oriented on a substrate. The base material may be a thermoplastic resin film for the protective film described above.

The retardation film may be, for example, a 1/4 wavelength retardation layer having reverse wavelength dispersibility, a positive C plate, a 1/2 wavelength retardation layer having positive wavelength dispersibility, a 1/4 wavelength retardation layer having positive wavelength dispersibility, or the like. The retardation film may be composed of 2 or more retardation layers, and may have a structure in which a 1/4 wavelength retardation layer having inverse wavelength dispersibility is combined with a positive C plate, a structure in which a 1/2 wavelength retardation layer having positive wavelength dispersibility is combined with a 1/4 wavelength retardation layer having positive wavelength dispersibility, or the like, for example.

The retardation film and the protective film may have a moisture permeability of 500 g/(m ². Multidot.24 hr) or less as measured at a temperature of 40 ℃ and a relative humidity of 90% by the cup method defined in JIS Z0208.

The surface protective film is a film used for protecting the surface of an optical film or the like as a protected object from damage or contamination, and for example, various optical films such as a polarizing plate, a protective film, a retardation film, a light diffusion sheet, and a reflection sheet as an optical film for a liquid crystal display device are generally circulated in a state in which the surface protective film is bonded to the surface (in the case where an adhesive layer is provided on one surface, the surface opposite to the adhesive layer). The surface protective film is usually peeled off after the optical film is attached to a liquid crystal cell or the like.

Examples of the substrate of the surface protective film include polyolefin resins such as polyethylene, polypropylene and polymethylpentene, fluorinated polyolefin resins such as polyvinyl fluoride, polyvinylidene fluoride and polyvinylidene fluoride, polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate and polyethylene terephthalate/isophthalate copolymer, polyamides such as nylon 6 and nylon 6, vinyl polymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol and vinylon (vinylon), cellulose resins such as triacetyl cellulose, diacetyl cellulose and cellophane (cellophane), (meth) acrylic resins such as polymethyl methacrylate, polyethyl acrylate and polybutyl acrylate, and other (meth) acrylic resins such as polystyrene, polycarbonate, polyarylate and polyimide.

The bonding layer may be an adhesive layer or an adhesive layer. In the case where the adhesive layer is an adhesive layer, an adhesive layer other than the adhesive layer may be used as the adhesive layer. When the adhesive layer is an adhesive layer, the adhesive layer may be composed of an adhesive composition containing a resin such as a (meth) acrylic resin, a rubber resin, a urethane resin, an ester resin, a silicone resin, and a polyvinyl ether resin as a main component. Among them, an adhesive composition comprising a (meth) acrylic resin excellent in transparency, weather resistance, heat resistance and the like as a base polymer is suitable. The adhesive composition may be an active energy ray-curable type or a thermosetting type.

When the adhesive layer is an adhesive layer, a polymer or copolymer of 1 or 2 or more (meth) acrylic esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate is preferably used as the (meth) acrylic resin (base polymer) used in the adhesive composition. The matrix polymer is preferably copolymerized with a polar monomer. Examples of the polar monomer include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, acrylamide, N-dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate.

The adhesive composition used when the adhesive layer is an adhesive layer may contain only the above-mentioned base polymer, and usually further contains a crosslinking agent. Examples of the crosslinking agent include metal ions having a valence of 2 or more, which form a metal salt of carboxylic acid with a carboxyl group, polyamine compounds, which form an amide bond with a carboxyl group, polyepoxide compounds, polyols, which form an ester bond with a carboxyl group, and polyisocyanate compounds, which form an amide bond with a carboxyl group. Among them, polyisocyanate compounds are preferable.

When the adhesive layer is used as the adhesive layer, the thickness of the adhesive layer is preferably 1 μm or more and 200 μm or less, more preferably 2 μm or more and 100 μm or less, still more preferably 2 μm or more and 80 μm or less, and particularly preferably 3 μm or more and 50 μm or less.

In the case where the adhesive layer is an adhesive layer, any suitable adhesive may be used as the adhesive. The adhesive may be an aqueous adhesive, an active energy ray-curable adhesive, or the like.

The thickness of the adhesive at the time of application can be set to any appropriate value. For example, the adhesive layer having a desired thickness can be obtained after curing or after heating (drying). The thickness of the adhesive layer is preferably 0.01 μm or more and 7 μm or less, more preferably 0.01 μm or more and 5 μm or less, still more preferably 0.01 μm or more and 2 μm or less, and most preferably 0.01 μm or more and 1 μm or less.

Examples of the aqueous adhesive include an aqueous polyvinyl alcohol resin solution and an aqueous two-part urethane emulsion adhesive.

The active energy ray-curable adhesive is an adhesive containing a curable compound that cures by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet-curable adhesive.

The curable compound may be a cationically polymerizable curable compound or a radically polymerizable curable compound. Examples of the cationically polymerizable curable compound include an epoxy compound (a compound having 1 or 2 or more epoxy groups in the molecule), an oxetane compound (a compound having 1 or 2 or more oxetane rings in the molecule), and a combination of these compounds. Examples of the radically polymerizable curable compound include (meth) acrylic compounds (compounds having 1 or 2 or more (meth) acryloyloxy groups in the molecule), other vinyl compounds having radically polymerizable double bonds, and combinations of these. A cationically polymerizable curable compound and a radically polymerizable curable compound may be used in combination. The active energy ray-curable adhesive generally further comprises at least one of a cationic polymerization initiator and a radical polymerization initiator for starting the curing reaction of the curable compound.

In order to improve the adhesiveness, a surface activation treatment may be performed on the bonding surface of at least one of the bonding layer and the optical film. Examples of the surface activation treatment include dry treatments such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment and the like), ozone treatment, UV ozone treatment, and ionizing active radiation treatment (ultraviolet treatment, electron beam treatment and the like). These surface activation treatments may be performed alone or in combination of 2 or more. Among them, corona treatment is preferable. The corona treatment can be performed at an output of, for example, 1kJ/m ² or more and 50kJ/m ² or less. The time for performing the corona treatment may be, for example, 1 second or more and 1 minute or less.

In the optical film with an adhesive layer of the present embodiment, it is preferable that the release film is attached to the surface of the adhesive layer and protected in advance until use. The optical film with an adhesive layer of the present embodiment to which a release film is attached can be produced by a method of forming an adhesive layer by applying an adhesive composition to a release film and further laminating a resin film on the resulting adhesive layer, and a method of forming an adhesive layer by applying an adhesive composition to a resin film and attaching a release film to the adhesive surface.

The optical film with the adhesive layer can be used for display devices such as organic electroluminescence (organic EL) display devices and liquid crystal display devices, and can be attached to the viewing side of an image display element of the display device.

The laminated structure of the optical film with the adhesive layer is not particularly limited as long as the optical film includes the adhesive layer laminated on the optical film.

The optical film 10 with an adhesive layer shown in fig. 1 includes a linear polarizing plate 11 and an adhesive layer 12. The linear polarization plate 11 includes, in order, a 1 st protective film 13, an adhesive layer 14, a polarizing plate 15, an adhesive layer 16, and a 2 nd protective film 17. The adhesive layer 12 is used for attaching to a liquid crystal cell of a liquid crystal display device as an image display element. A separator (release film) not shown may be provided on the surface of the pressure-sensitive adhesive layer 12 opposite to the linear polarizing plate 11.

The optical film 20 with an adhesive layer shown in fig. 2 includes an adhesive layer 21, a retardation film 22, a lamination layer 23, and a linear polarizing plate 24 in this order. The linear polarizing plate 24 includes, in order, a protective film 25, an adhesive layer 26, a polarizing plate 27, an adhesive layer 28, and a 2 nd protective film 29. The adhesive layer 21 can be used for attaching to a liquid crystal cell of a liquid crystal display device as an image display element. A separator (release film) not shown may be provided on the surface of the pressure-sensitive adhesive layer 21 opposite to the retardation film 22.

The optical films 10 and 20 with the pressure-sensitive adhesive layers shown in fig. 1 and 2 are only examples, and may have a laminated structure other than the above. For example, the protective film may have another layer such as a hard coat film, a film having an antiglare function, a film having an antireflection function, or the like.

< Display device >

The display device of the present invention comprises the above-described optical film with an adhesive layer. The optical film with an adhesive layer described above can be applied to display devices such as organic EL display devices, liquid crystal display devices, inorganic electroluminescence (inorganic EL) display devices, and electron emission display devices.

The display device 30 shown in fig. 3 is an organic EL display device including the optical film 10 with an adhesive layer shown in fig. 1, and the image display element 31 as a light-emitting layer including an organic EL element. The optical film 10 with an adhesive layer may be disposed on the viewing side of the image display element 31 through the adhesive layer 12.

Examples

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, "parts" and "%" indicating the amount or content used are mass-based unless otherwise specified.

Production example 1 production of (meth) acrylic resin (A)

A mixed solution of 86.4 parts of ethyl acetate, 68.7 parts of butyl acrylate, 20.0 parts of methyl acrylate, 10.0 parts of methyl methacrylate, 1.0 parts of 2-hydroxyethyl acrylate, and 0.3 parts of acrylic acid was added to a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer, and the temperature was raised to 60℃while replacing the air in the apparatus with nitrogen to thereby form an oxygen-free state. Then, a solution obtained by dissolving 0.10 part of azobisisobutyronitrile (polymerization initiator) in 13.7 parts of ethyl acetate was added in total. The concentration was maintained for 4 hours after the initiator addition. Finally, ethyl acetate was added so that the concentration of the (meth) acrylic resin (a) became 20 mass%, and an ethyl acetate solution of the (meth) acrylic resin (a) was prepared.

The glass transition temperature (Tg) of the obtained (meth) acrylic resin (A) was measured.

Tg is measured under conditions of a measurement temperature range of-80 to 50 ℃ and a temperature rising rate of 10 ℃ per minute in a nitrogen atmosphere using a Differential Scanning Calorimeter (DSC) 'EXSTAR DSC 6000', manufactured by SII NanoTechnology Co.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the obtained (meth) acrylic resin (A) were measured.

Mw and Mn were measured by standard polystyrene conversion under conditions of a sample concentration of 2mg/mL, a sample introduction amount of 100. Mu.L, a temperature of 40℃and a flow rate of 1 mL/min by placing 3 total of 1 branch of "TSKgel guardcolumn HHR-H (S)" and 3 branches of "TSKGEL GMHHR-H"2 branches, which are manufactured by Tosoh Co., ltd, as columns (column) in a GPC apparatus in series, and using tetrahydrofuran as an eluent. The monomer composition (mass%) of the monomer mixture used, and Tg, mw, and molecular weight distribution (Mw/Mn) of the resulting (meth) acrylic resin are summarized in table 1.

< Production examples 2 to 12>

An ethyl acetate solution of a (meth) acrylic resin was prepared in the same manner as in production example 1, except that the monomer composition was set as shown in table 1.

TABLE 1

The abbreviations in the "composition" column of Table 1 mean the following monomers.

BA butyl acrylate (homopolymer Tg: -54 ℃ C.)

OA octyl methacrylate (homopolymer Tg: -65 ℃ C.)

MA methyl acrylate (homopolymer Tg:10 ℃ C.)

MMA methyl methacrylate (homopolymer Tg:105 ℃ C.)

IBMA isobornyl methacrylate (homopolymer Tg:110 ℃ C.)

TBMA t-butyl methacrylate (homopolymer Tg:118 ℃ C.)

CHMA cyclohexyl methacrylate (homopolymer Tg:83 ℃ C.)

EMA Ethyl methacrylate (homopolymer Tg:65 ℃ C.)

HEA 2-hydroxyethyl acrylate

6HHA 6-hydroxyhexyl acrylate

4HBA 4-hydroxybutyl acrylate

AA acrylic acid

< Examples 1 to 13, comparative examples 1 to 3>

(1) Preparation of adhesive composition

To the ethyl acetate solution (resin concentration: 20%) of the (meth) acrylic resin obtained in the above production example, the crosslinking agent, the silane compound and the ionic compound in the amounts shown in table 2 (parts by mass) were mixed with respect to 100 parts by mass of the solid content of the solution, and ethyl acetate was further added so that the solid content concentration became 14% by mass, to prepare a solution of the adhesive composition. In table 2, the blending amount (parts by mass) of the (meth) acrylic resin, the crosslinking agent, the silane compound and the ionic compound is a solid content equivalent amount.

TABLE 2

Details of the components shown in Table 2 for short are as follows.

[ Cross-linking agent ]

B D-103 (ethyl acetate solution of trimethylolpropane adduct of toluene diisocyanate: solid content 75% by mass; sanjing chemical Co., ltd.)

[ Silane Compound ]

C-1:8-glycidoxy-octyl trimethoxysilane "KBM-4803", from Xinyue chemical industries, inc

C-2:1, 6-bis (trimethoxysilyl) hexane "KBM-3066", manufactured by Xinyue chemical industries, inc

[ Ionic Compound ]

D: methyltributylammonium = bis (tri) fluoromethylsulfonyl) imines

(2) Preparation of adhesive layer

Each of the adhesive compositions prepared in (1) above was applied to a release treated surface of a release film made of polyethylene terephthalate film (Diafoil MRV (V04) manufactured by mitsubishi chemical corporation) subjected to release treatment so that the thickness after drying became 25 μm using an applicator, and dried at 100 ℃ for 1 minute to prepare an adhesive layer (adhesive sheet).

(3) Determination of gel fraction of adhesive layer

The adhesive layer (adhesive sheet) produced in (2) was stored at 23 ℃ for 7 days at 60%. Gel fraction [ gel fraction at 23 ℃ C. (G23) ] was measured for the adhesive layer (adhesive sheet) after storage. The gel fraction can be measured according to the following [ a ] to [ d ]. The results are shown in Table 3.

[A] an adhesive layer having an area of about 8cm×about 8cm was bonded to a metal mesh (the mass of which is Wm) composed of SUS304 of about 10cm×about 10 cm.

[B] The bonded article obtained in the above item [ a ] was weighed, the mass thereof was Ws, and then folded in half 4 times so as to cover the adhesive layer, and was fixed by a stapler (Stapeler), and then weighed, and the mass thereof was Wb.

[C] the screen fixed by a stapler in [ b ] was placed in a glass container, 60mL of ethyl acetate was added thereto, and the glass container was immersed, and then stored at room temperature for 3 days.

[D] the screen was removed from the glass vessel, dried at 120℃for 4 hours, and weighed to give Wa, and the gel fraction was calculated according to the following formula:

gel fraction (% by mass) = [ { Wa- (Wb-Ws) -Wm }/(Ws-Wm) ] ×100.

(4) Determination of mechanical Strength in tensile test of adhesive layer

The adhesive layer (adhesive sheet) produced in (2) was stored at 23 ℃ for 7 days at 60%. The mechanical properties of the adhesive layer (adhesive sheet) after storage were measured in a tensile test.

First, a 3cm×12cm pressure-sensitive adhesive sheet was cut out and rolled to prepare a cylindrical test piece having a length of 3cm and a diameter of 2 mm. Then, the two ends of the test piece in the longitudinal direction were held by upper and lower clamps of a tensile tester [ AUTOGRAPH AG-1S tester manufactured by Shimadzu corporation ] so that the interval between the clamps became 1cm, and a tensile test was performed at a tensile speed of 100 mm/min under an environment of a temperature of 23 ℃ and a relative humidity of 55% until the test piece was broken. Based on the obtained stress-strain curve, the fracture stress, the fracture strain, and the fracture energy per unit volume are calculated. The results are shown in Table 3.

(5) Manufacture of polarizing plate

A protective film of triacetyl cellulose resin having a thickness of 40 μm, which was subjected to saponification treatment, was bonded to both sides of a polarizing plate having a thickness of 12 μm obtained by subjecting iodine to uniaxial stretching and adsorption orientation of a polyvinyl alcohol film, via a water-based adhesive, to thereby produce a polarizing plate.

(6) Production of polarizing plate with adhesive layer

The surface (adhesive layer surface) of the adhesive layer formed in (2) opposite to the separator was bonded to the outer surface of the protective film on the surface of the polarizing plate formed in (5) by a laminator, and then cured at a temperature of 23 ℃ and a relative humidity of 60% for 7 days, to obtain a polarizing plate with an adhesive layer.

(6) Evaluation of heat resistance durability of laminated optical film

After the separator was peeled off from the polarizing plate with an adhesive layer produced in the above (4), the adhesive layer was attached to both sides of an alkali-free glass substrate [ Eagle XG "] manufactured by corning corporation so as to be crossed nicols. The obtained test piece with a glass substrate attached (polarizing plate with an adhesive layer attached to a glass substrate) was pressurized in an autoclave at a temperature of 50℃and a pressure of 5kg/cm ² (490.3 kPa) for 20 minutes to prepare a sample for evaluation. The following heat resistance and durability test was performed using this sample.

[ Heat durability test ]

The fabricated samples were kept at a temperature of 110 ℃ for 750 hours under dry conditions.

For each sample after the test, the presence or absence of swelling and peeling at the interface between the adhesive layer and the glass substrate, and the presence or absence of foaming of the adhesive layer were visually observed, and the heat resistance and durability were evaluated based on the following evaluation criteria. The results are shown in Table 3.

A, slight swelling, peeling, cracking, foaming and other appearance changes were confirmed.

The appearance changes such as swelling, peeling, cracking, foaming and the like were observed to be slightly large.

And C, confirming large appearance changes such as swelling, peeling, cracking, foaming and the like.

The appearance changes such as swelling, peeling, cracking, foaming and the like were confirmed to be very large.

TABLE 3

Symbol description

10. 20 Optical film with adhesive layer, 11, 24 linear polarizing plate, 12 adhesive layer, 13, 25 first protective film, 14, 16, 26, 28 adhesive layer, 15, 27 polarizing plate, 17, 29 second protective film, 21 adhesive layer, 22 retardation film, 23 adhesive layer, 30 display device, 31 image display element.

Claims (11)

1. An adhesive composition comprising (meth) acrylic resin (A), crosslinking agent (B), and silane compound (C),

The (meth) acrylic resin (a) comprises:

a structural unit derived from an alkyl methacrylate (a) having a homopolymer glass transition temperature of 30 ℃ or higher, which is1 part by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the total structural units constituting the (meth) acrylic resin (a);

a structural unit derived from a hydroxyl group-containing (meth) acrylate (b) represented by the following formula (I) in an amount of 0.3 to 5.5 parts by mass based on 100 parts by mass of the total structural units constituting the (meth) acrylic resin (A), and

Structural units derived from carboxyl-containing monomers (c),

The mass ratio (c)/(b) of the structural unit derived from the carboxyl group-containing monomer (c) to the structural unit derived from the hydroxyl group-containing (meth) acrylate (b) represented by the formula (I) is 0.06 or more and 1.0 or less

In the formula (I) of the present invention,

N represents an integer of 1 to 5,

A ¹ represents a hydrogen atom or an alkyl group,

X ¹ represents a methylene group optionally having a substituent, and when n is 2 or more, X ¹ is optionally the same or different.

2. The adhesive composition according to claim 1, wherein the homopolymer has a glass transition temperature of 30 ℃ or higher and the homopolymer of the alkyl methacrylate (a) has a glass transition temperature of 80 ℃ or higher.

3. The adhesive composition according to claim 1, wherein the alkyl methacrylate (a) having a glass transition temperature of 30 ℃ or higher of the homopolymer comprises at least 1 selected from the group consisting of methyl methacrylate, t-butyl methacrylate, isobornyl methacrylate and cyclohexyl methacrylate.

4. The adhesive composition according to any one of claims 1 to 3, wherein the (meth) acrylic resin (a) has a weight average molecular weight of 100 to 320 ten thousand.

5. The adhesive composition according to any one of claims 1 to 3, wherein the crosslinking agent (B) contains an aromatic isocyanate compound, and the adhesive composition contains 0.2 parts by mass or more and 5.0 parts by mass or less of the crosslinking agent (B) per 100 parts by mass of the (meth) acrylic resin (a).

6. An adhesive layer comprising the adhesive composition of any one of claims 1 to 3.

7. An optical film with an adhesive layer comprising an optical film, and the adhesive layer of claim 6 laminated on the optical film.

8. The optical film with adhesive layer of claim 7, wherein the optical film comprises a polarizer.

9. A display device comprising the optical film with adhesive layer of claim 7.

10. A display device comprising the optical film with adhesive layer of claim 8.

11. An adhesive layer having a rupture energy per unit volume of 1.2X10 ⁶J/m³ or more.