JP6758869B2 - Adhesive composition, adhesive layer, and optical member with adhesive layer - Google Patents

Description

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition, and an optical member including the pressure-sensitive adhesive layer.

Polarizing plates made by laminating and laminating a protective film on one or both sides of a polarizer are image display devices such as liquid crystal display devices and organic electroluminescence (organic EL) display devices, especially mobile phones, smartphones, and tablet terminals in recent years. It is an optical member widely used in various mobile devices such as. An optical member such as a polarizing plate is often used by being bonded to another member (for example, an optical member such as a liquid crystal cell in a liquid crystal display device) via an adhesive layer [for example, Japanese Patent Application Laid-Open No. 2010-229321]. See Gazette (Patent Document 1)]. For this reason, for example, a polarizing plate is often marketed in the form of a polarizing plate with an adhesive layer in which an adhesive layer is previously provided on one surface of the polarizing plate.

JP-A-2010-229321

Durability is required for the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer for bonding optical members. That is, the adhesive layer attached to the optical member and incorporated in the image display device or the like may be placed in a high temperature or high temperature and high humidity environment, or may be placed in an environment in which high temperature and low temperature are repeated. However, the pressure-sensitive adhesive layer is required to be able to suppress defects that may occur due to dimensional changes of adjacent optical members even in these environments. The defects include floating and peeling at the interface between the pressure-sensitive adhesive layer and the optical member adjacent thereto, and foaming of the pressure-sensitive adhesive layer.

However, the conventional pressure-sensitive adhesive composition may have insufficient durability when bonded to an optical member as a pressure-sensitive adhesive layer, and the surface of the optical member to which the pressure-sensitive adhesive layer is bonded has surface activity such as corona treatment. Durability was sometimes insufficient, especially when the surface was difficult to be effectively activated by the chemical treatment.

The present invention is a pressure-sensitive adhesive composition having good durability when bonded as a pressure-sensitive adhesive layer to the surface even if the surface of the optical member is a surface that is difficult to be effectively activated even by a surface activation treatment. It is an object of the present invention to provide an adhesive layer containing the above, and an optical member with an adhesive layer provided with the adhesive layer.

The present invention provides the following pressure-sensitive adhesive composition, pressure-sensitive adhesive layer, and optical member with pressure-sensitive adhesive layer.
[1] A (meth) acrylic containing a structural unit derived from a (meth) acrylic monomer having a hydroxyl group, having a content of 3.5% by weight or less and a glass transition temperature of -25 ° C or less. With 100 parts by weight of the based resin (A)
Aromatic isocyanate-based cross-linking agent (B) 0.3 to 1 part by weight and
At least one compound (C) selected from the organic acid salt (C-1) and the compound (C-2) containing an alkyleneoxy group, and
Contains,
When the organic acid salt (C-1) is contained, the content thereof is 0.0001 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A).
When the compound (C-2) containing an alkyleneoxy group is contained, the content thereof is 0.1 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A). Composition.

[2] The pressure-sensitive adhesive composition according to [1], wherein the compound (C-2) containing an alkyleneoxy group is a compound containing at least one double bond and at least one alkylenedioxy group in the molecule. ..

[3] The pressure-sensitive adhesive composition according to [1] or [2], wherein the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 0.5% by weight or more.

[4] The pressure-sensitive adhesive composition according to any one of [1] to [3], which further contains an ionic compound (D).

[5] The pressure-sensitive adhesive composition according to any one of [1] to [4], which further contains the silane compound (E).

[6] The pressure-sensitive adhesive composition was formed into layers on a film made of a cyclic polyolefin resin, and the layered pressure-sensitive adhesive composition was stored on a non-alkali glass plate in an environment at a temperature of 23 ° C. for 24 hours. The peeling force when peeling from the non-alkali glass plate later was set to P (CO) 23.
The pressure-sensitive adhesive composition is formed into layers on a film made of a cyclic polyolefin resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate and stored for 48 hours in an environment at a temperature of 50 ° C. The ratio of the P (CO) 50 to the P (CO) 23 (P (CO) 50 / P (CO) 23), where the peeling force when peeling from the alkaline glass plate is P (CO) 50. The pressure-sensitive adhesive composition according to any one of [1] to [5], wherein the pressure is 3.2 or more.

[7] The pressure-sensitive adhesive composition is formed into layers on a film made of a (meth) acrylic resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate for 24 hours in an environment at a temperature of 23 ° C. The peeling force when peeling from the non-alkali glass plate after storage was set to P (AC) 23.
The pressure-sensitive adhesive composition is formed into layers on a film made of a (meth) acrylic resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate and stored for 48 hours in an environment at a temperature of 50 ° C. The ratio of the P (AC) 50 to the P (AC) 23 (P (AC) 50 / P (AC), where the peeling force when peeling from the non-alkali glass plate is P (AC) 50. The pressure-sensitive adhesive composition according to any one of [1] to [5], wherein 23) is 3.2 or more.

[8] Containing the organic acid salt (C-1) and the compound (C-2) containing the alkyleneoxy group,
The content of the organic acid salt (C-1) is 0.0001 to 0.1 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A).
The content of the compound (C-2) containing an alkyleneoxy group is 0.1 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A), [1] to [7]. The pressure-sensitive adhesive composition according to any one of.

[9] A pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition according to any one of [1] to [8].
[10] An optical member with an adhesive layer, which comprises an optical member and an adhesive layer according to [9] laminated on the optical member.

[11] The optical member with an adhesive layer according to [10], wherein the surface of the optical member on which the adhesive layer is laminated has a contact angle change rate of 40% or less when corona treatment is performed.

[12] The optical member includes a polarizer and a protective film laminated on the polarizer.
The optical member with an adhesive layer according to [11], wherein the surface is the surface of the protective film.

[13] The optical member with an adhesive layer according to [11] or [12], wherein the surface is a corona-treated surface.

[14] The optical member with an adhesive layer according to any one of [10] to [13], further comprising a glass substrate laminated on the adhesive layer.

[15] An optical member with an adhesive layer having a resin film and an adhesive layer laminated on at least one surface of the resin film.
The pressure-sensitive adhesive layer contains the pressure-sensitive adhesive composition according to any one of [1] to [8].
The peeling force when peeling from the non-alkali glass plate after being stored for 24 hours in an environment of a temperature of 23 ° C. in a state of being laminated on the non-alkali glass plate by the adhesive layer was defined as P23.
P50 and P23 when the peeling force when peeling from the non-alkali glass plate after being stored for 48 hours in an environment of a temperature of 50 ° C. in a state of being laminated on the non-alkali glass plate by the pressure-sensitive adhesive layer is P50. An optical member with an adhesive layer having a ratio (P50 / P23) of 3.2 or more.

According to the present invention, it is possible to provide a pressure-sensitive adhesive composition having good durability, a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition, and an optical member with a pressure-sensitive adhesive layer having the pressure-sensitive adhesive layer.

It is the schematic sectional drawing which shows an example of the optical member with an adhesive layer which concerns on this invention. It is the schematic sectional drawing which shows another example of the optical member with an adhesive layer which concerns on this invention. It is the schematic sectional drawing which shows still another example of the optical member with an adhesive layer which concerns on this invention. It is the schematic sectional drawing which shows still another example of the optical member with an adhesive layer which concerns on this invention.

<Adhesive composition>
[1] (Meta) Acrylic resin (A)
The (meth) acrylic resin (A) is a polymer containing a structural unit derived from a (meth) acrylic monomer having a hydroxyl group, and preferably, in addition to this structural unit, the following formula (I):

It is a polymer containing a structural unit derived from (meth) acrylic acid ester represented by (meth) as a main component. In the present specification, "(meth) acrylic" means acrylic and / or methacrylic, and "(meth)" when referring to (meth) acrylate or the like has the same meaning.

In the above formula (I), R ¹ represents a hydrogen atom or a methyl group, and R ² is an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms, or 1 to 1 carbon atoms. Represents an aralkyl group having 7 to 21 carbon atoms which may be substituted with 10 alkoxy groups. R ² is preferably an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms.

Examples of the (meth) acrylic acid ester represented by the formula (I) include (meth) acrylic acid alkyl ester, and specific examples thereof include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, and (meth). (Meta) acrylic acid alkyl ester with linear alkyl moieties such as n-propyl acrylate, n-butyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate; ) Includes (meth) acrylic acid alkyl esters having branched alkyl moieties such as isopropyl acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate. The number of carbon atoms in the alkyl moiety of the (meth) acrylic acid alkyl ester is preferably 1 to 8, and more preferably 1 to 6.

When R ² is an alkyl group substituted with an alkoxy group, i.e., specific examples of the (meth) acrylic acid ester represented by formula (I) when R ² is an alkoxyalkyl group, (meth) acrylic Includes 2-methoxyethyl acid, ethoxymethyl (meth) acrylate and the like. The number of carbon atoms of the alkyl group in the above alkoxyalkyl group is preferably 1 to 8, and more preferably 1 to 6. The number of carbon atoms of the alkoxy group in the above alkoxyalkyl group is preferably 1 to 8, and more preferably 1 to 4. Specific examples of the (meth) acrylic acid ester represented by the formula (I) in the case where R ² is an aralkyl group having 7 to 21 carbon atoms include benzyl (meth) acrylate and the like. The carbon number of the aralkyl group is preferably 7 to 11.

As the (meth) acrylic acid ester represented by the formula (I), only one type may be used alone, or two or more types may be used in combination. Among them, the (meth) acrylic acid ester preferably contains (meth) acrylic acid alkyl ester, more preferably contains acrylic acid alkyl ester, and further preferably contains n-butyl acrylate. The (meth) acrylic resin (A) preferably contains 50% by weight or more of the structural units derived from n-butyl acrylate in all the structural units constituting the resin (A). Of course, in addition to n-butyl acrylate, other (meth) acrylic acid ester represented by the formula (I) can also be used in combination.

The content of the structural unit derived from the (meth) acrylic acid ester represented by the formula (I) is usually 60% by weight or more and less than 100% by weight in all the structural units constituting the (meth) acrylic resin (A). Yes, preferably 70-99.9% by weight, more preferably 80-99.6% by weight.

The (meth) acrylic resin (A) contains a structural unit derived from a (meth) acrylic monomer having a hydroxyl group. Inclusion of this structural unit is advantageous in improving the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer. The (meth) acrylic monomer having a hydroxyl group is preferably a (meth) acrylic acid ester having a hydroxyl group. Specific examples of the (meth) acrylic acid ester having a hydroxyl group include 2-hydroxyethyl (meth) acrylic acid, 3-hydroxypropyl (meth) acrylic acid, 4-hydroxybutyl (meth) acrylic acid, and 2 (meth) acrylic acid. Hydroxyl-containing alkyl esters of (meth) acrylic acid such as- (2-hydroxyethoxy) ethyl, 2- or 3-chloro-2-hydroxypropyl (meth) acrylic acid, and poly such as diethylene glycol mono (meth) acrylate. It contains a partial esterified product of a functional alcohol and (meth) acrylic acid. From the viewpoint of the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability (particularly heat resistance) of the pressure-sensitive adhesive layer, the monomer having a hydroxyl group is preferably a (meth) acrylic acid ester having a hydroxyl group. More preferably, it is a hydroxyl group-containing alkyl ester of (meth) acrylic acid. The number of carbon atoms in the alkyl portion of the hydroxyl group-containing alkyl ester of (meth) acrylic acid is preferably 1 to 8, and more preferably 1 to 6.

The content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 3.5% by weight or less, preferably 3% by weight, based on all the structural units constituting the (meth) acrylic resin (A). % Or less, more preferably 2.5% by weight or less, still more preferably 2% by weight or less. If the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group exceeds 3.5% by weight, the durability of the pressure-sensitive adhesive layer, particularly the heat resistance, is insufficient. On the other hand, the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is usually 0.1% by weight or more, preferably 0.2% by weight or more, and more preferably 0.5% by weight. % Or more. If the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is less than 0.1% by weight, the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer are insufficient. ..

The (meth) acrylic resin (A) can contain a structural unit derived from a monomer having a polar functional group other than the (meth) acrylic monomer having a hydroxyl group. The monomer having this polar functional group is preferably a (meth) acrylic monomer having a polar functional group. Examples of the polar functional group contained in the monomer include a carboxyl group (free carboxyl group), an amino group, a heterocyclic group (for example, an epoxy group) and the like.

Specific examples of other polar functional group-containing monomers include carboxyl-containing monomers such as (meth) acrylic acid, β-carboxyethyl (meth) acrylate; acryloylmorpholine, vinylcaprolactam, N-vinyl-. Complexes such as 2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2,5-dihydrofuran. Monomer having a ring group; a monomer having an amino group different from that of a heterocycle such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and dimethylaminopropyl (meth) acrylate. including. As the monomer having other polar functional groups, only one kind may be used alone, or two or more kinds may be used in combination.

In addition to the (meth) acrylic monomer having a hydroxyl group, a monomer having another polar functional group, especially a (meth) acrylic monomer having a carboxyl group, can be used in combination with the pressure-sensitive adhesive layer. It is advantageous in improving the adhesion to the optical member and the durability (particularly heat resistance) of the adhesive layer.

The content of the structural unit derived from the monomer having another polar functional group, preferably the (meth) acrylic monomer having a carboxyl group, is in all the structural units constituting the (meth) acrylic resin (A). , It is preferably 5% by weight or less, and more preferably 4% by weight or less. If the content of the structural unit derived from a monomer having another polar functional group exceeds 5% by weight, the durability of the pressure-sensitive adhesive layer, particularly the heat resistance, tends to be insufficient. On the other hand, the content of the structural unit derived from the monomer having another polar functional group is usually 0.1% by weight or more, preferably 0.2% by weight or more, more preferably 0.2% by weight or more when it is contained. Is 0.3% by weight or more. If the content of the structural unit derived from a monomer having another polar functional group is less than 0.1% by weight, the effect of use is hardly recognized. The structural units derived from all the monomers having polar functional groups including the (meth) acrylic monomer having a hydroxyl group are usually 0. Of all the structural units constituting the (meth) acrylic resin (A). It is 1 to 8.5% by weight, preferably 0.2 to 7% by weight.

The (meth) acrylic resin (A) is a monomer having one olefinic double bond and at least one aromatic ring in the molecule (however, the monomer represented by the above formula (I) or It may further contain a structural unit derived from the above-mentioned monomer having a polar functional group.). A preferable example is a (meth) acrylic monomer having an aromatic ring. The (meth) acrylic monomer having such an aromatic ring also includes neopentyl glycol benzoate (meth) acrylate and the like, and in particular, the following formula (II):

A (meth) acrylic acid ester having an aryloxyalkyl group such as a phenoxyethyl group-containing (meth) acrylic acid ester represented by is preferable. Only one type of monomer having one olefinic double bond and at least one aromatic ring in the molecule, such as a phenoxyethyl group-containing (meth) acrylic acid ester, may be used alone. 2 Seeds or more may be used together.

In the above formula (II), R ³ represents a hydrogen atom or a methyl group, n represents an integer of 1 to 8, and R ⁴ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group. When R ⁴ is an alkyl group, its carbon number can be about 1 to 9, when it is an aralkyl group, its carbon number is about 7 to 11, and when it is an aryl group, its carbon number is 6. It can be about 10.

Methyl, butyl, nonyl and the like as alkyl groups having 1 to 9 carbon atoms constituting R ⁴ in the formula (II), and benzyl, phenylyl, naphthylmethyl and the like as aralkyl groups having 7 to 11 carbon atoms. Examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, naphthyl and the like.

Specific examples of the phenoxyethyl group-containing (meth) acrylic acid ester represented by the formula (II) include 2-phenoxyethyl (meth) acrylate, 2- (2-phenoxyethoxy) ethyl (meth) acrylate, and ethylene oxide. It contains (meth) acrylic acid ester of modified nonylphenol, 2- (o-phenylphenoxy) ethyl (meth) acrylic acid and the like. Among them, the phenoxyethyl group-containing (meth) acrylic acid ester includes (meth) acrylic acid 2-phenoxyethyl, (meth) acrylic acid 2- (o-phenylphenoxy) ethyl and / or (meth) acrylic acid 2- (2). -Preferably containing phenoxyethoxy) ethyl.

The content of the structural unit derived from the monomer having an aromatic ring is usually 0 to 20% by weight (for example, 6 to 12% by weight) in all the structural units constituting the (meth) acrylic resin (A). However, in order to keep the glass transition temperature of the (meth) acrylic resin (A) within a predetermined range described later, it may be preferable not to contain a structural unit derived from a monomer having an aromatic ring.

The (meth) acrylic resin (A) is other than the (meth) acrylic monomer represented by the formula (I) described above, the monomer having a polar functional group, and the monomer having an aromatic ring. It may contain a structural unit derived from a monomer (hereinafter, also referred to as “other monomer”). Specific examples of other monomers are derived from (meth) acrylic monomers having an alicyclic structure in the molecule (preferably (meth) acrylic acid esters having an alicyclic structure in the molecule). Constituent units, structural units derived from styrene-based monomers, structural units derived from vinyl-based monomers, structural units derived from monomers having multiple (meth) acryloyl groups in the molecule, (meth) acrylamide. Includes structural units derived from compounds. As for other monomers, only one kind may be used alone, or two or more kinds may be used in combination.

The alicyclic structure in the (meth) acrylic acid ester having an alicyclic structure in the molecule is a cycloparaffin structure having usually 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of the (meth) acrylic acid ester having an alicyclic structure include isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclododecyl (meth) acrylate, (meth). Includes methylcyclohexyl acrylate, trimethylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclohexylphenyl (meth) acrylate, cyclohexyl α-ethoxyacrylate and the like.

Specific examples of styrene-based monomers are styrene; alkyl styrenes such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, and octyl styrene; Halogenized styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene; including nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene and the like.

Specific examples of vinyl-based monomers 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; Contains vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone, vinylcarbazole; conjugated diene monomers such as butadiene, isoprene and chloroprene; acrylonitrile, methacrylonitrile and the like.

Specific examples of monomers having a plurality of (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol. Two (meth) in the molecule, such as di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate. Monomer having an acryloyl group; including a monomer having three (meth) acryloyl groups in the molecule such as trimethylolpropane tri (meth) acrylate.

Specific examples of (meth) acrylamide compounds include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, and N- (4-hydroxy). Butyl) (meth) acrylamide, N- (5-hydroxypentyl) (meth) acrylamide, N- (6-hydroxyhexyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, 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-acrylloylamino-2-methyl-1-propanesulfonic acid, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) (meth) acrylamide, N- (Propoxymethyl) (meth) acrylamide, N- (1-methylethoxymethyl) (meth) acrylamide, N- (1-methylpropoxymethyl) (meth) acrylamide, N- (2-methylpropoxymethyl) (meth) acrylamide [Also known as: N- (isobutoxymethyl) (meth) acrylamide], N- (butoxymethyl) (meth) acrylamide, N- (1,1-dimethylethoxymethyl) (meth) acrylamide, N- (2-methoxyethyl) ) (Meta) 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 [also known as N- (2-isobutoxyethyl) (meth) Acrylamide], N- (2-butoxyethyl) (meth) acrylamide, N- [2- (1,1-dimethylethoxy) ethyl] (meth) acrylamide and the like. Of these, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide, and N- (2-methylpropoxymethyl) acrylamide are preferably used.

The (meth) acrylic resin (A) contains a structural unit derived from other monomers in a proportion of usually 0 to 20% by weight, preferably 0 to 10% by weight, among all the structural units constituting the resin (A). ..

The pressure-sensitive adhesive composition may contain two or more types of (meth) acrylic resins belonging to the (meth) acrylic resin (A). Further, the pressure-sensitive adhesive composition may contain another (meth) acrylic resin different from the (meth) acrylic resin (A). Examples of other (meth) acrylic resins are (meth) acrylic resins having a structural unit derived from the (meth) acrylic monomer represented by the formula (I) and having no polar functional group. Is. However, the pressure-sensitive adhesive composition preferably contains the (meth) acrylic resin (A) as a main component, and the content of the (meth) acrylic resin (A) is the content of all the (meth) acrylic resins. In the total, it is preferably 60% by weight or more, more preferably 80% by weight or more, and further preferably 90% by weight or more.

The (meth) acrylic resin (A) has a glass transition temperature (Tg) of −25 ° C. or lower, preferably −30 ° C. or lower, as measured by a differential scanning calorimeter (DSC). According to the pressure-sensitive adhesive composition according to the present invention, which contains a (meth) acrylic resin (A) having a Tg of −25 ° C. or lower, the adhesiveness between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer are improved. Can be improved. From the viewpoint of durability, the Tg of the (meth) acrylic resin (A) is usually −55 ° C. or higher, preferably −50 ° C. or higher.

Further, according to the pressure-sensitive adhesive composition according to the present invention, which contains a (meth) acrylic resin (A) having a Tg of −25 ° C. or lower, it is possible to shorten the curing time of the pressure-sensitive adhesive layer. That is, the adhesive layer (adhesive sheet) is generally cured in order to allow the crosslinking reaction to proceed to the extent that appropriate handleability and processability can be obtained. However, the adhesive composition according to the present invention. According to the report, it is possible to shorten the curing time of the pressure-sensitive adhesive layer required for the cross-linking reaction to proceed sufficiently.

The weight average molecular weight (Mw) of the (meth) acrylic resin (A) in terms of standard polystyrene by gel permeation chromatography (GPC) is preferably in the range of 500,000 to 2 million, and is 600,000 to 1.8 million. It is more preferable that it is in the range of. When Mw is 500,000 or more, the adhesion between the adhesive layer and the optical member is improved in a high temperature and high humidity environment, and the possibility of floating or peeling between the adhesive layer and the optical member is low. Moreover, the reworkability of the pressure-sensitive adhesive layer tends to be improved. Further, when Mw is 2 million or less, even if the dimensions of the optical member change when the pressure-sensitive adhesive layer is attached to the optical member, the pressure-sensitive adhesive layer tends to follow the change in the dimensions and fluctuate easily. It is advantageous in terms of adhesion between the pressure-sensitive adhesive layer and the optical member and durability of the pressure-sensitive adhesive layer, and due to the above-mentioned followability, when the optical member with the pressure-sensitive adhesive layer is applied to a liquid crystal display device, the peripheral edge of the liquid crystal cell. There is no difference between the brightness of the part and the brightness of the center, and there is a tendency that white spots and color unevenness are suppressed. The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually about 2 to 10, preferably 3 to 7.

The (meth) acrylic resin (A) and other (meth) acrylic resins that can be used in combination are produced by known methods such as a solution polymerization method, a massive polymerization method, a suspension polymerization method, and an emulsion polymerization method. be able to. A polymerization initiator is usually used in the production of (meth) acrylic resins. The polymerization initiator is used in an amount of about 0.001 to 5 parts by weight based on a total of 100 parts by weight of all the monomers used in the production of the (meth) acrylic resin. Further, the (meth) acrylic resin may be produced by a method in which polymerization is allowed to proceed by an active energy ray such as ultraviolet rays.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator and the like are used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone. Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexane-1-carbonitrile). 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2'-azobis (2-methylpropio) Nate), azo compounds such as 2,2'-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butylhydroperoxide, benzoyl peroxide, tert-butylperoxybenzoate, cumenehydroper Organics such as oxides, diisopropylperoxydicarbonate, dipropylperoxydicarbonate, tert-butylperoxyneodecanoate, tert-butylperoxypivalate, (3,5,5-trimethylhexanoyl) peroxide Peroxides: Inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide can be mentioned. In addition, a redox-based initiator in which a peroxide and a reducing agent are used in combination can also be used as the polymerization initiator.

As a method for producing the (meth) acrylic resin, the solution polymerization method is preferable among the methods shown above. An example of the solution polymerization method is that the monomer to be used and the organic solvent are mixed, a thermal polymerization initiator is added under a nitrogen atmosphere, and the temperature is about 40 to 90 ° C., preferably about 50 to 80 ° C. for 3 to 15 hours. It is to stir to some extent. In order to control the reaction, the monomer or the thermal polymerization initiator may be added continuously or intermittently during the polymerization, or may be added 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 propyl alcohol and isopropyl alcohol; acetone, methyl ethyl ketone and methyl isobutyl ketone. Ketones and the like can be used.

[2] Aromatic isocyanate-based cross-linking agent (B)
The pressure-sensitive adhesive composition further contains an aromatic isocyanate-based cross-linking agent (B). The aromatic isocyanate-based cross-linking agent (B) is a compound having an aromatic ring and having two or more isocyanate groups in the molecule. By using an aromatic isocyanate compound as a cross-linking agent, the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer can be improved.

Specific examples of the aromatic isocyanate-based cross-linking agent (B) are tolylene diisocyanate, chlorophenylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, naphthalene diisocyanate and the like. The aromatic isocyanate-based cross-linking agent (B) includes polyhydric alcohol compound adducts of these isocyanate compounds (for example, adducts of trimethylolpropane), isocyanurates, bullet-type compounds, polyether polyols, polyester polyols, and acrylics. It contains derivatives such as urethane prepolymer type isocyanate compounds that have been subjected to an addition reaction with polyols, polybutadiene polyols, polyisoprene polyols and the like. As the aromatic isocyanate-based cross-linking agent (B), only one type may be used alone, or two or more types may be used in combination.

Among the aromatic isocyanate-based cross-linking agents (B), the aromatic isocyanate-based cross-linking agent in which an isocyanate group is bonded to the aromatic ring effectively improves the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer. It can be preferably used to enhance the temperature. Specific examples of the aromatic isocyanate-based cross-linking agent in which an isocyanate group is bonded to the aromatic ring include tolylene diisocyanate, chlorophenylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, naphthalene diisocyanate and the like.

The content of the aromatic isocyanate-based cross-linking agent (B) is 0.3 to 1 part by weight, preferably 0.35 to 0.9 parts by weight, based on 100 parts by weight of the (meth) acrylic resin (A). Is. If the content of the aromatic isocyanate-based cross-linking agent (B) is less than 0.3 parts by weight, the pressure-sensitive adhesive layer may take a sufficient curing time depending on the surface material of the optical member on which the pressure-sensitive adhesive layer is laminated. And the adhesion with the optical member becomes insufficient. Further, depending on the material of the surface of the optical member on which the pressure-sensitive adhesive layer is laminated, the durability when the pressure-sensitive adhesive layer is attached to the optical member is lowered. If the content of the aromatic isocyanate-based cross-linking agent (B) exceeds 1 part by weight, the adhesion between the pressure-sensitive adhesive layer and the optical member becomes insufficient even if a sufficient curing time is taken. Further, the durability when the pressure-sensitive adhesive layer is attached to the optical member, particularly the heat resistance, is lowered.

[3] Compound (C)
The pressure-sensitive adhesive composition further contains at least one compound (C) selected from the organic acid salt (C-1) and the compound (C-2) containing an alkyleneoxy group. According to the pressure-sensitive adhesive composition according to the present invention containing the compound (C), the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability when the pressure-sensitive adhesive layer is attached to the optical member, particularly heat resistance. Can be improved. Further, it is possible to shorten the curing time of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive composition may contain only an organic acid salt (C-1), may contain only a compound containing an alkyleneoxy group (C-2), or may contain both of them. You may be doing it.

The organic acid salt (C-1) is preferably a salt composed of an organic acid having a carboxylic acid terminal and a base, that is, an organic carboxylic acid salt. When an organic carboxylate is used as the organic acid salt (C-1), the counter cation of the carboxylate anion is preferably a trivalent or lower counter cation. Only one type of organic acid salt (C-1) may be used, or two or more types may be used in combination.

Examples of the above-mentioned counter cation include a metal ion, an ammonium ion, and a cation having a heterocyclic structure. Preferred examples of metal ions include alkali metal ions and alkaline earth metal ions. Preferred examples of cations having a heterocyclic structure include pyrrolinium ions, imidazolium ions, triazonium ions, pyrrolidinium ions, pyridinium ions, and piperidinium ions.

Examples of the carboxylate anion of the organic acid salt (C-1) include linear saturated alkyl carboxylate ions such as formic acid ion, acetate ion, propionate ion, heptanate ion, octanate ion, and laurate ion; Meta) Linear unsaturated alkyl carboxylate ions such as acrylic acid and oleic acid; aromatic carboxylate ions such as benzoic acid and cinnamic acid; carboxylate ions having a heterocyclic structure such as nicotinic acid; succinic acid Dicarboxylate ions such as fumaric acid and phthalic acid; and carboxylate anions having an oxyethylene skeleton such as 2- (2-ethoxy) ethoxycarboxylate ion.

The content of the organic acid salt (C-1) is 0.0001 to 5 parts by weight, preferably 0.0005 to 5 parts by weight, based on 100 parts by weight of the (meth) acrylic resin (A). It is more preferably 0.0007 to 3 parts by weight, further preferably 0.001 to 1 part by weight, and particularly preferably 0.0015 to 0.5 part by weight. If the content is within this range, the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability when the pressure-sensitive adhesive layer is attached to the optical member are good, and the curing time of the pressure-sensitive adhesive layer is long. A pressure-sensitive adhesive composition that can be shortened can be obtained.

The compound containing an alkyleneoxy group (C-2) is preferably a compound containing at least one double bond and at least one alkyleneoxy group in the molecule. The alkyleneoxy group is preferably contained in the compound (C-2) as an alkylenedioxy group (-O-alkylene-O-). A preferred example of the double bond is a double bond contained in the (meth) acryloyl group. As the compound (C-2) containing an alkyleneoxy group, only one type may be used, or two or more types may be used in combination. According to the pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition containing the compound (C-2) containing an alkyleneoxy group, the peeling force of the release film laminated on the surface of the pressure-sensitive adhesive layer with respect to the pressure-sensitive adhesive layer is enhanced by heat. Can also be suppressed.

A preferable example of the above alkylenedioxy group is alkylenedioxy having 1 to 4 carbon atoms from the viewpoint of adhesion between the pressure-sensitive adhesive layer and the optical member and durability when the pressure-sensitive adhesive layer is attached to the optical member. a group, more preferably a straight-chain or branched alkylenedioxy group having 1 to 3 carbon atoms, more preferably an ethylene dioxy group _{(-O-C 2 H 4 -O-} ). The same applies to the example of an alkyleneoxy group which is not an alkylenedioxy group. The alkyleneoxy group is preferably an alkyleneoxy group having 1 to 4 carbon atoms, and more preferably a linear or linear group having 1 to 3 carbon atoms. a branched alkylene group, more preferably an ethylene group - is a _{(-O-C 2 H 4)} .

From the viewpoint of the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability when the pressure-sensitive adhesive layer is attached to the optical member, the compound (C-2) is represented by the following formula (C-2a):

It is preferable to contain a compound (C-2a) containing a (meth) acryloyl group represented by, and more preferably to be composed of the compound (C-2a). In the formula, h represents an integer of 1 to 6, Q ¹ represents a hydrogen atom or a methyl group, and Q ⁰ represents a h-valent group having at least one alkylenedioxy group. The compound (C-2) may contain two or more kinds of the compound (C-2a). h is preferably an integer of 1-3.

The h-valent group having at least one alkylenedioxy group represented by Q ⁰ can be an h-valent hydrocarbon group having at least one alkylenedioxy group, and preferably at least one ethylenedioxy group. It is a 1 to 3 valent hydrocarbon group having an oxy group. Examples of the hydrocarbon group include the groups represented by Q ⁰¹ , Q ⁰² , Q ⁰³ and Q ⁰⁴ below.

In Q ⁰¹ , Q ² represents an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group which may be substituted with an alkoxy group having 1 to 3 carbon atoms, and L represents a single bond or 1 to 4 carbon atoms. Represents the alkylene group of, and i represents an integer of 1 to 50 (for example, 1 to 30). The number of carbon atoms of the aryl group that may be Q ² are preferably 6 to 20 carbon atoms in the aralkyl group is preferably 7 to 20. In Q ⁰² , j represents an integer of 1 to 40 (for example, 1 to 30). In Q ⁰³ , y and z each independently represent an integer of 1 to 40 (for example, 1 to 30), and y + z can be an integer of 1 to 40 (for example, 1 to 30). In ^Q04 , e, f and g each independently represent an integer of 1 to 20 (for example, 1 to 10), and e + f + g can be an integer of 1 to 30 (for example, 1 to 25).

As the preferably used compound (C-2a), the following formula (C-2a-1):

The compound represented by (C-2a-1) can be mentioned. The compound (C-2) may contain two or more kinds of the compound (C-2a-1). The compound (C-2a-1) is a compound in which Q ⁰ in the above formula (C-2a) is Q ⁰¹ . Q ¹ , L, i, and Q ² in the equation have the same meanings as described above. In compound (C-2a-1), L is preferably a single bond, i is preferably an integer of 7 to 35, and more preferably an integer of 9 to 25. Q ² is preferably an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 20 carbon atoms, and specific examples of Q ² include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and a phenyl group. A biphenyl group is exemplified.

Specific examples of the compound (C-2a-1) may be mentioned those Q ^1, L, i, Q ² are shown in Table 1 below.

Another example of the preferably used compound (C-2a) is a compound in which Q ⁰ in the above formula (C-2a) is Q ⁰⁴ . In this case, h in the above formula (C-2a) is 3. The compound (C-2) may contain two or more kinds of compounds in which Q ⁰ is Q ⁰⁴ . In ^Q04 , e + f + g is preferably an integer of 5 to 25.

Another example of the preferably used compound (C-2a) is a compound in which Q ⁰ in the above formula (C-2a) is Q ⁰³ . In this case, h in the above formula (C-2a) is 2. The compound (C-2) may contain two or more compounds in which Q ⁰ is Q ⁰³ . In Q ⁰³ , y + z is preferably an integer of 5 to 25.

The content of the compound (C-2) is 0.1 to 5 parts by weight, preferably 0.15 to 5 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the (meth) acrylic resin (A). Is 0.2 to 4.5 parts by weight, more preferably 0.5 to 4 parts by weight. If the content is within this range, the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability when the pressure-sensitive adhesive layer is attached to the optical member are good, and the curing time of the pressure-sensitive adhesive layer is long. A pressure-sensitive adhesive composition that can be shortened can be obtained, and further, an effect of suppressing an increase in peeling force can be obtained.

[4] Ionic compound (D)
The pressure-sensitive adhesive composition may further contain an ionic compound (D) as an antistatic agent for imparting antistatic properties to the pressure-sensitive adhesive layer. The ionic compound (D) is a compound having an inorganic cation or an organic cation and an inorganic anion or an organic anion. Two or more kinds of ionic compounds (D) may be used.

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

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

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

The inorganic anion, e.g., chloride anion [Cl ^-], bromide anion [Br ^-], iodide anion [I ^-], tetrachloro aluminate anions [AlCl ₄ ^-], hepta-chloro-di aluminate anion [Al ₂ Cl ₇ ^-], tetrafluoroborate anion [BF ₄ ^-], hexafluorophosphate anion [PF ₆ ^-], perchlorate anion [ClO ₄ ^-], nitrate anion [NO ₃ ^-], hexafluoro ah cell anion [AsF ₆ ^-], hexafluoroantimonate anion [SbF ₆ ^-], hexafluoro niobate anions [NbF ₆ ^-], hexafluoro tantalate anion [TaF ₆ ^-], dicyanamide anion [(CN) ₂ N ^-] and the like include Be done.

The organic anions, for example, acetate anion [CH ₃ COO ^-], trifluoroacetate anion [CF ₃ COO ^-], methanesulfonate anion [CH ₃ SO ₃ ^-], trifluoromethanesulfonate anion [CF ₃ SO ₃ ^-], p- toluenesulfonate anion _{[p-CH 3 C 6 H 4} SO 3 - ], bis (fluorosulfonyl) imide anion [(FSO _{2) 2} N ^-], bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N ^-], tris (trifluoromethanesulfonyl) meth acetonide anion _{[(CF 3 SO 2) 3 C} - ], dimethyl phosphinate anion [(CH _{3) 2} POO ^-], (poly) hydrofluoroether fluoride anion [ F (HF) _n ^-] (n is about 1 to 3), thiocyanate anion [SCN ^-], perfluorobutane sulfonate anion [C ₄ F ₉ SO ₃ ^-], bis (pentafluoroethane sulfonyl) imide anion [(C _{2 F 5 SO 2) 2 N} - ], perfluoro butanoate anion [C ₃ F ₇ COO ^-], (trifluoromethanesulfonyl) (trifluoromethane carbonyl) imide anion _{[(CF 3 SO 2) (CF} 3 CO) N ^-], perfluoro-1,3-disulfonate anion ^{_{[- O 3 S (CF 2)}} 3 SO 3 - ], carbonate anions [CO ₃ ^2-], and the like.

Among the above-mentioned anion components, the anion component containing a fluorine atom is preferably used because it gives an ionic compound (D) having excellent antistatic performance. Specific examples of the anion 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 (D) can be appropriately selected from the combination of the above-mentioned cationic component and anionic component. Examples of the ionic compound (D) having an organic cation, classified according to the structure of the organic cation, are as follows.

Pyridinium salt:
N-hexylpyridinium hexafluorophosphate,
N-octylpyridinium hexafluorophosphate,
N-octyl-4-methylpyridinium hexafluorophosphate,
N-Butyl-4-methyllpyridinium hexafluorophosphate,
N-decylpyridinium bis (fluorosulfonyl) imide,
N-dodecylpyridinium bis (fluorosulfonyl) imide,
N-Tetradecylpyridinium bis (fluorosulfonyl) imide,
N-Hexadecylpyridinium 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-octylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,
N-Butyl-4-methyllpyridinium bis (trifluoromethanesulfonyl) imide.

Imidazole salt:
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 methanesulfonate,
1-Butyl-3-methylimidazolium bis (fluorosulfonyl) imide.

Pyrrolidinium salt:
N-Butyl-N-Methylpyrrolidinium Hexafluorophosphate,
N-Butyl-N-Methylpyrrolidinium bis (fluorosulfonyl) imide,
N-Butyl-N-Methylpyrrolidinium bis (trifluoromethanesulfonyl) imide.

Quaternary ammonium salt:
Tetrabutylammonium hexafluorophosphate,
Tetrabutylammonium p-toluenesulfonate,
(2-Hydroxyethyl) trimethylammonium bis (trifluoromethanesulfonyl) imide,
(2-Hydroxyethyl) trimethylammonium dimethylphosphinate.

Further, examples of the ionic compound (D) having an inorganic cation include the following.

Lithium bromide,
Lithium iodide,
Lithium tetrafluoroborate,
Lithium hexafluorophosphate,
Lithium isothiocyanate,
Lithium Park Lorate,
Lithium trifluoromethanesulfonate,
Lithium bis (fluorosulfonyl) imide,
Lithium bis (trifluoromethanesulfonyl) imide,
Lithium bis (pentafluoroethanesulfonyl) imide,
Lithium tris (trifluoromethanesulfonyl) methanide,
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 (D) is preferably solid at room temperature. Compared with the case of using the ionic compound (D) which is liquid at room temperature, the antistatic performance can be maintained for a long period of time. From the viewpoint of long-term stability of such antistatic properties, the ionic compound (D) preferably has a melting point of 30 ° C. or higher, more preferably 35 ° C. or higher. On the other hand, if the melting point is too high, the compatibility with the (meth) acrylic resin (A) becomes poor, so the melting point is preferably 90 ° C. or lower, more preferably 70 ° C. or lower, still more preferably less than 50 ° C. Is.

The content of the ionic compound (D) in the pressure-sensitive adhesive composition is preferably 0.2 to 8 parts by weight, more preferably 0.2 parts by weight, based on 100 parts by weight of the (meth) acrylic resin (A). It is ~ 5 parts by weight, more preferably 0.3 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight. When the content of the ionic compound (D) is 0.2 parts by weight or more, it is advantageous for improving the antistatic performance, and when it is 8 parts by weight or less, it is advantageous for maintaining the durability of the pressure-sensitive adhesive layer. ..

[5] Silane compound (E)
The pressure-sensitive adhesive composition can further contain the silane compound (E). As a result, the adhesion between the pressure-sensitive adhesive layer and the optical member such as a glass substrate can be improved.

Examples of the silane compound (E) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and N- (2). -Aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ) Ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3 -Glysidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane and the like can be mentioned. Two or more kinds of silane compounds may be used.

The silane compound (E) may be of the silicone oligomer type. When the silicone oligomer is shown in the form of a (monomeric) oligomer, for example, the following can be mentioned.

3-Mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Mercaptopropyltriethoxysilane-tetramethoxysilane copolymer,
A mercaptopropyl group-containing copolymer such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;
Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer,
Mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer,
Mercaptomethyltriethoxysilane-tetramethoxysilane copolymer,
Mercaptomethyl group-containing copolymers such as mercaptomethyltriethoxysilane-tetraethoxysilane copolymer;
3-Glydoxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Glydoxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Glydoxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-Glydoxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-Glydoxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-Glydoxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Glydoxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
3-Glydoxypropyl group-containing copolymers such as 3-glycidoxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-Methoxyloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-Metacryloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Methacryloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
A copolymer containing a methacryloyloxypropyl group, such as 3-methacryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-Acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-Acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-Acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-Acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Acryloyloxypropyl group-containing copolymers such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
Vinyl Trimethoxysilane-Tetramethoxysilane Copolymer,
Vinyltrimethoxysilane-tetraethoxysilane copolymer,
Vinyltriethoxysilane-tetramethoxysilane copolymer,
Vinyltriethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetramethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldiethoxysilane-tetramethoxysilane copolymer,
Vinyl group-containing copolymers such as vinylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-Aminopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Aminopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Aminopropyltriethoxysilane-tetramethoxysilane copolymer,
3-Aminopropyltriethoxysilane-tetraethoxysilane copolymer,
3-Aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-Aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Amino group-containing copolymers such as 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer.

Most of the silane compounds (E) exemplified above are liquids. The content of the silane compound (E) in the pressure-sensitive adhesive composition is usually 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the (meth) acrylic resin (A). Parts, more preferably 0.2 to 0.4 parts by weight. When the content of the silane compound (E) is 0.01 parts by weight or more, the effect of improving the adhesion between the pressure-sensitive adhesive layer and the optical member such as a glass substrate can be easily obtained. Further, when the content is 10 parts by weight or less, bleeding out of the silane compound (E) from the pressure-sensitive adhesive layer can be suppressed.

[6] Other components The pressure-sensitive adhesive composition includes a cross-linking catalyst, a weather-resistant stabilizer, a tack fire, a plasticizer, a softener, a dye, a pigment, an inorganic filler, light-scattering fine particles, and a (meth) acrylic resin (A). Additives such as resin can be contained. In addition, it is also useful to add an ultraviolet curable compound to the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer and then irradiate it with ultraviolet rays to cure it to obtain a harder pressure-sensitive adhesive layer. Examples of the cross-linking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin and melamine resin.

<Adhesive layer>
The pressure-sensitive adhesive layer according to the present invention contains the above-mentioned pressure-sensitive adhesive composition according to the present invention, and typically comprises the pressure-sensitive adhesive composition according to the present invention. The pressure-sensitive adhesive layer can be obtained by dissolving or dispersing each component constituting the pressure-sensitive adhesive composition in a solvent to obtain a solvent-containing pressure-sensitive adhesive composition, then applying the pressure-sensitive adhesive layer onto a base film and drying the pressure-sensitive adhesive layer. .. The pressure-sensitive adhesive layer according to the present invention is excellent in adhesion and durability, and can shorten the required curing time.

The base film is generally a plastic film, and a typical example thereof is a release film (separator) that has been subjected to a mold release treatment. The release film may be one in which, for example, the surface on which the pressure-sensitive adhesive layer of the film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarate is formed is subjected to a mold release treatment such as silicone treatment. it can. For example, an adhesive composition is directly applied to a release-treated surface of a release film to form an adhesive layer, and the adhesive layer with a release film is laminated on an optical member to obtain an optical member with an adhesive layer. Can be done. Further, the pressure-sensitive adhesive composition may be directly applied to the surface of the optical member 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 member with a pressure-sensitive adhesive layer. When the pressure-sensitive adhesive layer is provided on the surface of the optical member, it is preferable to perform surface activation treatment, for example, plasma treatment, corona treatment, etc. on the bonding surface of the optical member and / or the bonding surface of the pressure-sensitive adhesive layer. It is more preferable to apply the treatment.

The thickness of the pressure-sensitive adhesive layer is preferably 10 to 45 μm, more preferably 10 to 30 μm, and even more preferably 15 to 25 μm. When the thickness of the pressure-sensitive adhesive layer is within this range, it is advantageous for the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability when the pressure-sensitive adhesive layer is attached to the optical member. For the same reason, the pressure-sensitive adhesive layer preferably has a gel fraction in the range of 30 to 85%.

In the pressure-sensitive adhesive composition of the present invention, the pressure-sensitive adhesive composition is formed into a layer on a film made of a cyclic polyolefin resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate under an environment of a temperature of 23 ° C. After storage for 24 hours, the peeling force when peeling the layered pressure-sensitive adhesive composition from the non-alkali glass plate together with the film made of the cyclic polyolefin resin is set to P (CO) 23, and the film is made of the cyclic polyolefin resin. After forming into layers and storing the layered pressure-sensitive adhesive composition on a non-alkali glass plate for 48 hours in an environment of a temperature of 50 ° C., the layered pressure-sensitive adhesive composition is obtained from the non-alkali glass plate based on the cyclic polyolefin. When the peeling force when peeling together with the film made of resin is P (CO) 50, the ratio of P (CO) 50 to P (CO) 23 (P (CO) 50 / P (CO) 23) is It is preferably 3.2 or more, more preferably 3.5 or more, and even more preferably 3.8 or more. If an optical member containing a film made of a cyclic polyolefin resin is attached to a liquid crystal cell made of inorganic glass on the film side via an adhesive layer containing such an adhesive composition, immediately after the attachment. The so-called reworkability, in which the optical member is peeled off and replaced with a new optical member, is improved, and the peeling force is increased by heating after bonding, so that the optical member can be bonded to the liquid crystal cell more strongly. ,preferable.

Further, in the pressure-sensitive adhesive composition of the present invention, the pressure-sensitive adhesive composition is formed into a layer on a film made of a (meth) acrylic resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate at a temperature of 23 ° C. The peeling force when peeling the layered pressure-sensitive adhesive composition from the non-alkali glass plate together with the film made of the (meth) acrylic resin after being stored for 24 hours in the above environment is P (AC) 23, and (meth). A layered adhesive composition is formed on a film made of an acrylic resin, and the layered pressure-sensitive adhesive composition is stored on a non-alkali glass plate for 48 hours in an environment of a temperature of 50 ° C. When the peeling force when peeling the agent composition together with the film made of the (meth) acrylic resin is P (AC) 50, the ratio of P (AC) 50 to P (AC) 23 (P (AC) ) 50 / P (AC) 23) is preferably 3.2 or more, more preferably 3.5 or more, and even more preferably 3.8 or more. If an optical member containing a film made of a (meth) acrylic resin is bonded to a liquid crystal cell made of inorganic glass on the film side via a pressure-sensitive adhesive layer containing such a pressure-sensitive adhesive composition, the bonding is performed. Immediately after that, the optical member is peeled off and replaced with a new optical member, so-called reworkability is improved, and the peeling force is increased by heating after bonding, so the optical member is more strongly bonded to the liquid crystal cell. Obtained and preferred.

The P (CO) 23 or P (AC) 23 is preferably 0.3 to 5 N / 25 mm, more preferably 0.5 to 5 N / 25 mm, and even more preferably 0.5 to 3 N / 25 mm. When P (CO) 23 or P (AC) 23 is in such a range, the reworkability and the adhesion to the liquid crystal cell are good. The P (CO) 50 or P (AC) 50 is preferably 1 to 15 N / 25 mm, more preferably 1.5 to 15 N / 25 mm, and further preferably 2 to 13 N / 25 mm. When P (CO) 50 or P (AC) 50 is in such a range, the reworkability and the adhesion to the liquid crystal cell are good.

The pressure-sensitive adhesive composition of the present invention contains an organic acid salt (C-1) and a compound (C-2), and the content of the organic acid salt (C-1) is (meth) acrylic resin (A) 100. It is 0.0001 to 0.1 parts by weight, further 0.0005 to 0.05 parts by weight, particularly 0.001 to 0.02 parts by weight, and the content of the compound (C-2) is high. It is preferably 0.1 to 5 parts by weight, more preferably 0.15 to 4 parts by weight, and particularly preferably 0.2 to 3 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A).

By containing the organic acid salt (C-1) and the compound (C-2) in the above amounts, the ratio of P (CO) 50 to P (CO) 23 (P (CO) 50 / P (CO) 23) can be easily adjusted to preferably 3.2 or more, more preferably 3.5 or more, still more preferably 3.8 or more.

Further, by containing the organic acid salt (C-1) and the compound (C-2) in the above amounts, the ratio of P (AC) 50 to P (AC) 23 (P (AC) 50 / P ( It is easy to adjust AC) 23) to preferably 3.2 or more, more preferably 3.5 or more, still more preferably 3.8 or more.

<Optical member with adhesive layer>
The pressure-sensitive adhesive layer according to the present invention can be suitably used as a pressure-sensitive adhesive layer for bonding members to each other, particularly optical members. The optical member with an adhesive layer according to the present invention may be, for example, one in which an adhesive layer is laminated on a certain optical member, and another optical member is laminated and laminated on the outer surface of the adhesive layer. Can be

[1] First Embodiment One preferred embodiment of the optical member with an adhesive layer according to the present invention includes a resin film as an optical member and an adhesive layer laminated on at least one surface thereof. The resin film is attached to an optical film such as a polarizer, a protective film, or a retardation film, or an optical film to be protected, and is used for the purpose of protecting the surface from scratches and stains (protection). Film) can be mentioned.

The polarizer is a film having a function of extracting linearly polarized light from incident natural light, and a preferable example is that a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film. Is what you are doing. The thickness of the polarizer is not particularly limited, but is usually 0.5 to 35 μm.

The protective film is a translucent (preferably optically transparent) resin, for example, a polyolefin resin such as a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin (norbornen resin or the like). A film made of a cellulose resin such as triacetyl cellulose or diacetyl cellulose; a polyester resin; a polycarbonate resin; a (meth) acrylic resin; a polystyrene resin; a polyether ether ketone resin; a thermoplastic resin such as a polysulfone resin. There can be.

Examples of the chain polyolefin resin include homopolymers of chain olefins such as polyethylene resin and polypropylene resin, and copolymers composed of two or more kinds of chain olefins.

Cyclic polyolefin resin is a general term for resins that are polymerized using cyclic olefin as a polymerization unit. Specific examples of the cyclic polyolefin resin include an open (co) polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and a chain olefin such as ethylene and propylene (typically). Is a random copolymer), a graft polymer obtained by modifying these with an unsaturated carboxylic acid or a derivative thereof, and a hydride thereof. Of these, a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

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

The polyester-based resin is a resin other than the above-mentioned cellulosic resin having an ester bond, and is generally composed of a polyvalent carboxylic acid or a derivative thereof and a polycondensate of a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylic acid. As the polyhydric alcohol, a diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, cyclohexanedimethanol and the like.

Specific examples of the polyester-based resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethylterephthalate, and polycyclohexanedimethylnaphthalate.

The polycarbonate resin is composed of a polymer in which monomer units are bonded via a carbonate group. The polycarbonate-based resin may be a resin called modified polycarbonate having a modified polymer skeleton, a copolymerized polycarbonate, or the like.

The (meth) acrylic resin can be a polymer containing a methacrylic acid ester as a main monomer, and is preferably a polymer in which a small amount of other comonomer components are copolymerized with the polymer. The (meth) acrylic resin is more preferably a copolymer of methyl methacrylate and methyl acrylate, and a third monofunctional monomer may be further copolymerized.

Examples of the third monofunctional monomer include methyl methacrylate such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate. Methacrylic acid esters; acrylic acid esters other than methyl acrylate such as ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate. Hydroxyalkylacrylic acid esters such as methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, butyl 2- (hydroxymethyl) acrylate. Classes; unsaturated acids such as methacrylic acid and acrylic acid; halogenated styrenes such as chlorostyrene and bromostyrene; substituted styrenes such as vinyltoluene and α-methylstyrene; non-substituted styrenes such as acrylonitrile and methacrylonitrile. Saturated nitriles; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; unsaturated imides such as phenylmaleimide and cyclohexylmaleimide can be mentioned. As the third monofunctional monomer, only one type may be used alone, or two or more types may be used in combination.

A polyfunctional monomer may be further copolymerized with the (meth) acrylic resin. Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and nonaethylene glycol di (meth) acrylate. Tetradeca Ethylene glycol di (meth) acrylate-like ethylene glycol or oligomers thereof having both terminal hydroxyl groups esterified with acrylic acid or methacrylic acid; propylene glycol or oligomers having both terminal hydroxyl groups esterified with acrylic acid or methacrylic acid. Acrylate; a hydroxyl group of a dihydric alcohol such as neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, butanediol di (meth) acrylate esterified with acrylic acid or methacrylic acid; bisphenol A , An alkylene oxide adduct of bisphenol A, or the hydroxyl groups at both ends of these halogen substituents esterified with acrylic acid or methacrylic acid; polyhydric alcohols such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid. Esterated products and those in which an epoxy group of glycidyl acrylate or glycidyl methacrylate is ring-added to these terminal hydroxyl groups; succinic acid, adipic acid, terephthalic acid, phthalic acid, dibasic acids such as halogen substituents thereof, and Examples thereof include those obtained by ring-opening addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate to these alkylene oxide adducts; aryl (meth) acrylates; aromatic divinyl compounds such as divinylbenzene. Of these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

The (meth) acrylic resin may be modified by further reacting between the functional groups of the copolymer. Examples of the reaction include a demethanol condensation reaction in a polymer chain between a methyl ester group of methyl acrylate and a hydroxyl group of methyl 2- (hydroxymethyl) acrylate, and a carboxyl group of acrylate and 2- (hydroxymethyl) acrylic. Examples thereof include a dehydration condensation reaction in a polymer chain with a hydroxyl group of methyl acid. Further, the (meth) acrylic resin may have any structure of a glutarimide derivative, a glutaric anhydride derivative, or a lactone ring structure.

The (meth) acrylic resin may contain an additive if necessary. Examples of the additive include a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a lightproofing agent, an impact resistance improving agent, a surfactant and the like.

The (meth) acrylic resin may contain acrylic rubber particles from the viewpoint of film forming property on the film, impact resistance of the film, and the like. Acrylic rubber particles are particles containing an elastic polymer mainly composed of an acrylic acid ester as an essential component, and have a single-layer structure substantially consisting of only this elastic polymer, or one elastic polymer. Examples thereof include a multi-layer structure having layers. An example of this elastic polymer is a crosslinked elastic copolymer containing alkyl acrylate as a main component and copolymerizing another copolymerizable vinyl monomer and a crosslinkable monomer. Examples of the alkyl acrylate that is the main component of the elastic polymer include methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like, and the alkyl group has about 1 to 8 carbon atoms. Acrylic acid having an alkyl group having 4 or more carbon atoms is particularly preferably used. Examples of other vinyl monomers copolymerizable with this alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid such as methyl methacrylate. Examples thereof include acid esters, aromatic vinyl compounds such as styrene, and vinyl cyan compounds such as acrylonitrile. Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di (meth) acrylate and butanediol di (). Examples thereof include (meth) acrylates of polyhydric alcohols such as meta) acrylates, alkenyl esters of (meth) acrylic acids such as allyl (meth) acrylates, and divinylbenzene.

A laminate of a film made of a (meth) acrylic resin containing no rubber particles and a film made of a (meth) acrylic resin containing rubber particles can also be used as a protective film.

The retardation film is an optical film that exhibits optical anisotropy, and in addition to the resins that can be used for the protective film, for example, polyvinyl alcohol-based resins, polyarylate-based resins, polyimide-based resins, and polyether sulfone-based resins. , Polyvinylidene fluoride / polymethylmethacrylate resin, liquid crystal polyester resin, ethylene-vinyl acetate copolymer saponified product, polyvinyl chloride resin, etc. by stretching a resin film about 1.01 to 6 times. It can be the obtained stretched film. Of these, a stretched film obtained by uniaxially stretching or biaxially stretching a polycarbonate resin film, a cyclic polyolefin resin film, a (meth) acrylic resin film or a cellulose resin film is preferable. Further, in the present specification, a zero retardation film is also included in the retardation film (however, it can also be used as a protective film). In addition, films called uniaxial retardation films, wide viewing angle retardation films, low photoelastic modulus retardation films and the like can also be applied as retardation films.

The zero retardation film refers to a film in which both the in-plane retardation value R _e and the thickness direction retardation value R _th are -15 to 15 nm. This retardation film is suitably used for a liquid crystal display device in IPS mode. The in-plane retardation value R _e and the thickness direction retardation value R _th are preferably −10 to 10 nm, and more preferably both −5 to 5 nm. The in-plane retardation value R _e and the thickness direction retardation value R _th referred to here are values at a wavelength of 590 nm.

The in-plane retardation value R _e and the thickness direction retardation value R _th are expressed by the following equations, respectively:
R _e = (n _{x −} n _y ) × d
R _th = [(n _x + n _y ) /2- _nz ] × d
Defined in. In the equation, n _x is the refractive index in the slow axis direction (x axis direction) in the film plane, and n _y is the phase advance axis direction in the film plane (y axis direction orthogonal to the x axis in the plane). It is the refractive index, n _z is the refractive index in the film thickness direction (the z-axis direction perpendicular to the film surface), and d is the film thickness.

As the zero retardation film, for example, a resin film made of a polyolefin resin such as a cellulose resin, a chain polyolefin resin and a cyclic polyolefin resin, a polyethylene terephthalate resin or a (meth) acrylic resin can be used. In particular, since the retardation value can be easily controlled and easily obtained, a cellulosic resin, a polyolefin resin, or a (meth) acrylic resin is preferably used. For example, a retardation film may be obtained by laminating a (meth) acrylic resin layer on one side or both sides of a retardation expression layer made of a resin different from the (meth) acrylic resin.

Further, a film in which optical anisotropy is expressed by coating and orientation of a liquid crystal compound and a film in which optical anisotropy is developed by coating an inorganic layered compound can also be used as a retardation film. In such a retardation film, what is called a temperature-compensated retardation film, and a rod-shaped liquid crystal sold by JX Nikko Niseki Energy Co., Ltd. under the trade name of "NH film" are tilt-oriented. Film, a film with tilt-oriented disc-shaped liquid crystal sold under the trade name of "WV film" by Fuji Film Co., Ltd., and a complete biaxial film sold by Sumitomo Chemical Co., Ltd. under the trade name of "VAC film". There are oriented type films, biaxially oriented films also sold by Sumitomo Chemical Co., Ltd. under the trade name of "new VAC film".

On the other hand, the surface protective film is a film used for the purpose of protecting the surface of an optical film or the like to be protected from scratches and dirt. For example, a polarizer, a protective film, and a position which are optical members for a liquid crystal display device. Various optical films such as a retardation film, a light diffusing sheet, and a reflective sheet are usually in a state where a surface protective film is attached to the surface (if the adhesive layer is provided on one side, the surface opposite to the adhesive layer). It is in circulation. The surface protective film is usually peeled off after the optical film is attached to a liquid crystal cell or the like.

As the base material of the surface protective film, for example, a polyolefin-based resin such as polyethylene, polypropylene, or polymethylpentene; a fluorinated polyolefin-based resin such as polyvinyl acetate, polyvinylidene fluoride, or ethylene polyvinyl acetate; polyethylene naphthate, polyethylene. Polyester resins such as terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate copolymer; polyamides such as nylon 6, nylon 6, 6; polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate Copolymers, ethylene-vinyl alcohol copolymers, polyvinyl alcohols, vinyl polymers such as vinylon; cellulose-based resins such as triacetyl cellulose, diacetyl cellulose, cellophane; polymethylmethacrylate, polyethylmethacrylate, polyacrylics Examples thereof include (meth) acrylic resins such as ethyl acid and butyl polyacrylate; and films made of thermoplastic resins such as polystyrene, polycarbonate, polyarylate and polyimide. The optical member with an adhesive layer according to the present invention in which the resin film is a surface protective film has an adhesive layer provided on the base material.

In the optical member with an adhesive layer according to the present embodiment, it is preferable to attach the above-mentioned release film to the surface of the adhesive layer to temporarily protect the optical member until use. In the optical member with an adhesive layer according to the present embodiment to which the release film is attached, an adhesive composition is applied on the release film to form an adhesive layer, and a resin film is further applied to the obtained adhesive layer. Can be produced by a method of laminating the above, a method of applying an adhesive composition on a resin film to form an adhesive layer, and a method of attaching a release film to the adhesive surface.

The optical member with an adhesive layer according to the present embodiment is peeled off from the non-alkali glass plate after being stored for 24 hours in an environment of a temperature of 23 ° C. in a state of being laminated on the non-alkali glass plate by the pressure-sensitive adhesive layer constituting the optical member. The peeling force at the time is P23, and the peeling force at the time of peeling from the non-alkali glass plate after being stored for 48 hours in an environment of a temperature of 50 ° C. in a state of being laminated on the non-alkali glass plate by the adhesive layer constituting the P23. When P50 is set, the ratio of P50 to P23 (P50 / P23) is 3.2 or more, further 3.5 or more, especially 3.8 or more, so that the so-called reworkability is good and the paste is applied. Since the peeling force is increased by heating after the reaction, the optical member can be more strongly bonded to the liquid crystal cell, which is preferable.

P23 is preferably 0.3 to 5 N / 25 mm, more preferably 0.5 to 5 N / 25 mm, and even more preferably 0.5 to 3 N / 25 mm. When P23 is in such a range, the reworkability and the adhesion to the liquid crystal cell are good. The P50 is preferably 1 to 15 N / 25 mm, more preferably 1.5 to 15 N / 25 mm, and even more preferably 2 to 13 N / 25 mm. When P50 is in such a range, the reworkability and the adhesion to the liquid crystal cell are good.

[2] Second Embodiment Another preferred embodiment of the optical member with a pressure-sensitive adhesive layer according to the present invention includes a laminate of resin films and a pressure-sensitive adhesive layer laminated on at least one surface thereof. The laminate of the resin film is preferably a laminate of optical films selected from optical films such as a polarizer, a protective film, and a retardation film. A typical example of a laminate of optical films is a polarizing plate. Also in the optical member with an adhesive layer according to the present embodiment, it is preferable that a release film is attached to the surface of the adhesive layer to temporarily protect the optical member until use.

As the polarizing plate, a linear polarizing plate having a property of absorbing linearly polarized light having a vibrating surface in a certain direction incident on the film surface and transmitting linearly polarized light having a vibrating surface orthogonal to the linearly polarized light, and a linearly polarized light having a property of being incident on the film surface in a certain direction Examples thereof include a polarizing separation plate having a property of reflecting linearly polarized light having a vibrating surface and transmitting linearly polarized light having a vibrating surface orthogonal to the linearly polarized light, and an elliptical polarizing plate in which a retardation film is laminated on a linearly polarizing plate.

The linear polarizing plate generally has a structure in which the above-mentioned protective film is bonded to one side or both sides of the above-mentioned polarizer. When protective films are attached to both sides of the polarizer, an adhesive layer can be formed on at least one surface of the protective film. When the protective film is attached to only one side of the polarizer, an adhesive layer can be formed on the surface of the polarizer (the surface on which the protective film is not attached). The elliptical polarizing plate is obtained by laminating a retardation film on a linear polarizing plate, and the linear polarizing plate generally has the same configuration as above. When laminating the pressure-sensitive adhesive layer on the elliptical polarizing plate, the pressure-sensitive adhesive layer is usually laminated on the retardation film side.

A specific example of the optical member with an adhesive layer when the optical member is a polarizing plate will be described with reference to the drawings. In the example shown in FIG. 1, a protective film 3 having a surface treatment layer 2 is attached to one side of the polarizer 1 on a surface opposite to the surface treatment layer 2 to form a polarizing plate 10. An adhesive layer 20 is provided on the surface of the polarizer 1 opposite to the protective film 3, and a polarizing plate with an adhesive layer (optical member with an adhesive layer) 25 is formed. The pressure-sensitive adhesive layer 20 can be attached to the glass substrate 30 on the surface opposite to the polarizing plate 10, but the glass substrate 30 will be described later.

The polarizing plate 25 with an adhesive layer shown in FIG. 2 is the same as that of FIG. 1 except that the polarizing plate 10 includes a second protective film 4 to be attached to the other surface of the polarizer 1. The pressure-sensitive adhesive layer 20 is laminated on the outer surface of the second protective film 4. The polarizing plate 25 with an adhesive layer shown in FIG. 3 is the same as that of FIG. 1 except that the polarizing plate 10 includes a retardation film 7 which is attached to the other surface of the polarizer 1 via the interlayer adhesive 8. Is. FIG. 2 shows that the polarizing plate 25 with an adhesive layer shown in FIG. 4 includes a retardation film 7 in which the polarizing plate 10 is attached to the outer surface of the second protective film 4 via the interlayer adhesive 8. Is the same as. In the examples shown in FIGS. 3 and 4, the pressure-sensitive adhesive layer 20 is attached to the retardation film 7.

The surface treatment layer 2 formed on the surface of the protective film 3 can be a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, or the like. It is also possible to provide a plurality of layers among these. As in the example shown in FIGS. 3 and 4, when the polarizing plate 10 includes the retardation film 7, a 1/4 wave plate is a suitable example of the retardation film 7 in a small and medium-sized liquid crystal display device. Can be mentioned. In this case, the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 are generally arranged so as to intersect at approximately 45 degrees, but the angle is 45 depending on the characteristics of the liquid crystal cell. It may be shifted to some extent from the degree. On the other hand, in the case of a large liquid crystal display device such as a television, a retardation film 7 having various retardation values according to the characteristics of the liquid crystal cell is used for the purpose of phase difference compensation and viewing angle compensation of the liquid crystal cell. .. In this case, the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 are generally arranged so as to be substantially orthogonal or substantially parallel to each other. When the retardation film 7 is composed of a 1/4 wave plate, a uniaxial or biaxial stretched film is preferably used. When the retardation film 7 is provided for the purpose of compensating for the phase difference and the viewing angle of the liquid crystal cell, in addition to the uniaxial or biaxially stretched film, the film is oriented in the thickness direction in addition to the uniaxially or biaxially stretched film. A film called an optical compensation film, such as a film obtained by applying a retardation-developing substance such as a liquid crystal on a support film and fixing the orientation, can also be used as the retardation film 7.

A general (meth) acrylic pressure-sensitive adhesive is usually used for the interlayer pressure-sensitive adhesive 8 in FIGS. 3 and 4, but it is of course possible to use the pressure-sensitive adhesive layer according to the present invention. When the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 are arranged so as to be substantially orthogonal or substantially parallel to each other as in the large liquid crystal display device described above, the interlayer adhesive is used. It is also possible to use an adhesive instead of 8. Examples of the adhesive include a water-based adhesive which is composed of an aqueous solution or an aqueous dispersion and exhibits adhesive strength by evaporating water as a solvent, and an ultraviolet curable adhesive which is cured by ultraviolet irradiation and exhibits adhesive strength. And so on. Adhesion of the polarizer 1 and the protective films 3 and 4 is also usually performed using an adhesive.

In the optical member with a pressure-sensitive adhesive layer according to the present embodiment, since the pressure-sensitive adhesive layer contains the pressure-sensitive adhesive composition according to the present invention, the adhesiveness and durability between the pressure-sensitive adhesive layer and the optical member are good. According to the present invention, even if the surface of the optical member to which the pressure-sensitive adhesive layer is bonded is a surface that is difficult to be activated by conventional surface activation treatments such as corona treatment and plasma treatment, it is adherent. An optical member with an adhesive layer having good adhesion between the agent layer and the optical member and durability can be obtained. The surface that is difficult to be activated by the surface activation treatment referred to here is, for example, a surface having a contact angle change rate of 40% or less, further 30% or less when the corona treatment is performed. The contact angle change rate is usually 0.1% or more, preferably 0.5% or more.

The contact angle change rate is calculated by the following formula:
Contact angle change rate (%) = {(contact angle before corona treatment-contact angle after corona treatment) / contact angle before corona treatment} x 100
Defined in. The contact angle after corona treatment is defined as the contact angle after performing one corona treatment on the surface under the conditions of an output of 0.3 kW and a line speed of 10 m / min, and then leaving it for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 60%. It is the contact angle when The contact angle is the contact angle with water, and the unit is "°".

The rate of change in contact angle when the above corona treatment is performed differs depending on the constituent material of the surface of the optical member. Examples of the thermoplastic resin having a contact angle change rate of 40% or less include (meth) acrylic resin, cellulosic resin, polyester resin, and polycarbonate resin. The surface of the optical member made of these thermoplastic resins can be the surface of an optical film such as a protective film or a retardation film.

[3] Third Embodiment Another preferred embodiment of the pressure-sensitive adhesive layered optical member according to the present invention is further on the outer surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layered optical member according to the first or second embodiment. Other optical members are laminated and laminated. The other optical member is preferably a glass substrate, and FIGS. 1 to 4 also show how the polarizing plate with an adhesive layer according to the second embodiment is attached to the glass substrate 30. ..

Examples of the glass substrate 30 include a glass substrate of a liquid crystal cell, antiglare glass, and sunglasses glass. Examples of the material of the glass substrate 30 include soda lime glass, low-alkali glass, and non-alkali glass. Above all, the glass substrate is preferably the glass substrate of the liquid crystal cell.

Normally, polarizing plates are laminated on both sides of a liquid crystal cell via an adhesive layer, but among these polarizing plates, only the polarizing plate arranged on the front side (visual side) of the liquid crystal cell is in the present invention. The polarizing plate with an adhesive layer may be used, or only the polarizing plate arranged on the back surface side (backlight side) of the liquid crystal cell may be the polarizing plate with an adhesive layer according to the present invention. Both of these may be polarizing plates with a pressure-sensitive adhesive layer according to the present invention. The driving method of the liquid crystal cell may be any conventionally known method. The polarizing plate arranged on the back surface side (backlight side) usually does not have the surface treatment layer 2. Various optical films known to be arranged on the back side of the liquid crystal cell, such as a brightness improving film, a condensing film, and a diffusion film, can be provided on the outer surface of the polarizing plate arranged on the back side.

An optical member with an adhesive layer, such as a polarizing plate with an adhesive layer, can be suitably used for a liquid crystal display device. The liquid crystal display device includes, for example, a personal computer including a notebook type, a desktop type, a PDA (Personal Digital Assistant), and the like; various mobile devices such as a smartphone and a tablet type terminal; a television; an in-vehicle display; an electronic dictionary; a digital camera; a digital It can be suitably used as a video camera; an electronic desktop computer; a liquid crystal display device for a clock or the like.

Hereinafter, 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, the portion indicating the amount used or the content and% are based on weight unless otherwise specified.

<Manufacturing Examples 1 to 7: Production of (meth) acrylic resin for adhesive layer>
A monomer mixture having the monomer composition shown in Table 2 (% by weight when the total amount of monomers is 100% by weight) in a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, and diluted with ethyl acetate. Was charged, and the internal temperature was raised to 55 ° C. while replacing the air in the apparatus with nitrogen gas to make it oxygen-free. Then, a total amount of a solution of azobisisobutyronitrile (polymerization initiator) in ethyl acetate was added. After adding the initiator, the temperature was maintained at this temperature for 1 hour, and then ethyl acetate was continuously added into the reaction vessel while maintaining the internal temperature at 54 to 56 ° C., and the concentration of the (meth) acrylic resin was 35% by weight. At that point, the addition of ethyl acetate was stopped, and the temperature was kept at this temperature until 12 hours had passed from the start of addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth) acrylic resin to 20% by weight to prepare an ethyl acetate solution of the (meth) acrylic resin.

The weight average molecular weight (Mw) and the glass transition temperature (Tg) of the obtained (meth) acrylic resin were measured. Mw has four columns of "TSKgel XL" manufactured by Toso Co., Ltd. and one "Shodex GPC KF-802" manufactured by Showa Denko Co., Ltd. and sold by Shoko Co., Ltd. as columns in the GPC device. A total of 5 bottles were arranged in series, and tetrahydrofuran was used as an eluent, and the measurement was performed by standard polystyrene conversion under the conditions of a sample concentration of 5 mg / mL, a sample introduction amount of 100 μL, a temperature of 40 ° C., and a flow velocity of 1 mL / min. Tg is measured using a differential scanning calorimeter (DSC) "EXSTAR DSC6000" manufactured by SII Nanotechnology Co., Ltd. under a nitrogen atmosphere, a measurement temperature range of -80 to 50 ° C, and a temperature rise rate of 10 ° C / min. did. The monomer composition (% by weight) of the monomer mixture used and the Mw and Tg of the obtained (meth) acrylic resin are summarized in Table 2.

The abbreviations in the "Monomer Composition" column of Table 2 mean the following monomers.
BA: n-butyl acrylate,
EHA: 2-ethylhexyl acrylate,
MA: Methyl acrylate,
AA: Acrylic acid,
HEA: 2-Hydroxyethyl acrylate.

<Examples 1 to 10, Comparative Examples 1 to 8>
(1) Preparation of Adhesive Composition The cross-linking agent (B), compound (C), and compound (C) shown in Table 3 with respect to 100 parts by weight of the solid content of the (meth) acrylic resin (A) obtained in the above production example. The silane compound (E) was mixed in an amount (part by weight) shown in Table 3 and ethyl acetate was further added so that the solid content concentration was 14% by weight to prepare a solution of the pressure-sensitive adhesive composition. When the product used contains a solvent or the like, the blending amount of each blended ingredient shown in Table 3 is the number of parts by weight as the active ingredient contained therein.

Details of each compounding ingredient shown by abbreviation in Table 3 are as follows.
B1: Ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%), "Coronate L" obtained from Nippon Polyurethane Industry Co., Ltd.,
B2: Hexamethylene diisocyanate isocyanurate, liquid with almost 100% active ingredient, "Coronate HXR" obtained from Nippon Polyurethane Industry Co., Ltd.,
C1: Sodium acetate: Obtained from Wako Pure Chemical Industries, Ltd. (To the pressure-sensitive adhesive composition, a 0.5% by weight solution was prepared and added by dissolving in ethyl alcohol).
C2: "AM-130G" obtained from Shin Nakamura Chemical Industry Co., Ltd. (the following formula:

Methoxylated polyethylene glycol acrylate represented by),
S1: 3-glycidoxypropyltrimethoxysilane, "KBM403" obtained from Shin-Etsu Chemical Co., Ltd.

(2) Preparation of Adhesive Layer A release film made of a polyethylene terephthalate film that has been subjected to a mold release treatment, each of the adhesive compositions prepared in (1) above [“PLR-382501” obtained from Lintec Co., Ltd., The release-treated surface of [referred to as a separator] was coated with an applicator so that the thickness after drying was 20 μm, and dried at 100 ° C. for 1 minute to prepare an adhesive layer (adhesive sheet).

(3) Preparation of Polarizing Plate with Adhesive Layer A first protective film made of the thermoplastic resin shown in Table 4 is adhered to one surface of a 23 μm-thick polarizer in which iodine is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film. A polarizing plate was produced by laminating via an agent and then laminating a second protective film made of (meth) acrylic resin on the other surface using an adhesive different from the above. Next, the outer surface of the first protective film was subjected to corona treatment once under the conditions of an output of 0.3 kW and a line speed of 10 m / min. Next, a surface (adhesive layer surface) opposite to the separator in the pressure-sensitive adhesive layer prepared in (2) above was bonded to the corona-treated surface by a laminator, and then the temperature was 23 ° C. and the relative humidity was 65%. After curing, a polarizing plate with an adhesive layer was obtained.

The abbreviations described in the "Protective film" column of Table 4 mean the following thermoplastic resins.
AC: (meth) acrylic resin (contact angle change rate based on the above definition: 17.2%),
PE: Polyester resin (contact angle change rate based on the above definition: 14.7%),
CE: Cellulose-based resin (contact angle change rate based on the above definition: 21.7%).

(4) Evaluation of Durability After peeling off the separator from the polarizing plate with an adhesive layer produced in (3) above, the adhesive layer surface is placed on both sides of a glass substrate for a liquid crystal cell [“Eagle XG” manufactured by Corning Inc.]. An evaluation sample was prepared by pasting so as to form a cross Nicol. The following three types of durability tests were carried out using this sample.
[Durability test]
-Heat resistance test that holds for 1000 hours under dry conditions at a temperature of 80 ° C.
Moisture resistance test that keeps for 1000 hours in an environment with a temperature of 60 ° C and a relative humidity of 90%.
A heat shock resistance (HS) test in which the operation of holding for 30 minutes under a dry condition at a temperature of 70 ° C. and then holding for 30 minutes under a dry condition at a temperature of -40 ° C. is set as one cycle, and this is repeated for 500 cycles.

The sample after each test was visually observed, and the durability was evaluated according to the following evaluation criteria. The results are shown in Table 4.

A: No change in appearance such as floating, peeling, foaming, etc.
B: There is almost no change in appearance such as floating, peeling, and foaming.
C: Many changes in appearance such as floating, peeling, and foaming are observed.
D: Appearance changes such as floating, peeling, and foaming are noticeably observed.

(5) Adhesion between the protective film and the pressure-sensitive adhesive layer and evaluation of the curing period A test piece having a width of 25 mm and a length of 150 mm was cut from the polarizing plate with the pressure-sensitive adhesive layer prepared in (3) above. Next, after peeling the separator from this test piece, it was fixed to an adhesion evaluation jig manufactured by Nippon System Group Co., Ltd., and the next peeling test was carried out. A test rubber piece [material: neoprene rubber, hardness: JIS A hardness 65] is applied to the surface of the pressure-sensitive adhesive layer, and the rubber piece is reciprocated 20 times on the test piece to rub the surface of the pressure-sensitive adhesive layer with the rubber piece. It was. The moving direction of the test rubber piece and the width direction of the test piece were parallel.

The surface of the test piece after the peeling test on the adhesive layer side was observed. In each of the Examples and Comparative Examples, the pressure-sensitive adhesive layer was peeled off on one end side in the width direction of the test piece after the peeling test, and a part of the pressure-sensitive adhesive layer remained on the other end side. The position of the remaining adhesive layer (position in the length direction of the test piece) was determined, and the distance from one end to the position was measured as the peeling distance. The results are shown in Table 4.

In each of the Examples and Comparative Examples, a polarizing plate with a pressure-sensitive adhesive layer was prepared using a pressure-sensitive adhesive layer having a curing period of 3 days and a pressure-sensitive adhesive layer having a curing period of 7 days, and a peeling test was conducted. When the peeling distance is 15 mm or less when the curing period is 7 days, it can be said that the adhesion between the protective film and the adhesive layer is good. Further, if the difference between the peeling distance when the curing period is 3 days and the peeling distance when the curing period is 7 days is 5 mm or less, it can be said that it is extremely advantageous in terms of shortening the curing period. In Comparative Example 2, when a cyclic polyolefin resin film having a contact angle change rate of 56.3% was used instead of the (meth) acrylic resin film as the protective film, the curing period was 3 days and 7 days. The peeling distances were 14 mm and 11 mm, respectively, and the durability according to the above measurement method was also relatively good.

<Manufacturing Examples 8 to 10: Production of (meth) acrylic resin for adhesive layer>
A monomer mixture having the monomer composition shown in Table 5 (% by weight when the total amount of monomers is 100% by weight) in a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, and diluted with ethyl acetate. Was charged, and the internal temperature was raised to 55 ° C. while replacing the air in the apparatus with nitrogen gas to make it oxygen-free. Then, a total amount of a solution of azobisisobutyronitrile (polymerization initiator) in ethyl acetate was added. After adding the initiator, the temperature was maintained at this temperature for 1 hour, and then ethyl acetate was continuously added into the reaction vessel while maintaining the internal temperature at 54 to 56 ° C., and the concentration of the (meth) acrylic resin was 35% by weight. At that point, the addition of ethyl acetate was stopped, and the temperature was kept at this temperature until 12 hours had passed from the start of addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth) acrylic resin to 20% by weight to prepare an ethyl acetate solution of the (meth) acrylic resin.

The weight average molecular weight (Mw) and the glass transition temperature (Tg) of the obtained (meth) acrylic resin were measured. Mw has four columns of "TSKgel XL" manufactured by Toso Co., Ltd. and one "Shodex GPC KF-802" manufactured by Showa Denko Co., Ltd. and sold by Shoko Co., Ltd. as columns in the GPC device. A total of 5 bottles were arranged in series, and tetrahydrofuran was used as an eluent, and the measurement was performed by standard polystyrene conversion under the conditions of a sample concentration of 5 mg / mL, a sample introduction amount of 100 μL, a temperature of 40 ° C., and a flow velocity of 1 mL / min. Tg is measured using a differential scanning calorimeter (DSC) "EXSTAR DSC6000" manufactured by SII Nanotechnology Co., Ltd. under a nitrogen atmosphere, a measurement temperature range of -80 to 50 ° C, and a temperature rise rate of 10 ° C / min. did. The monomer composition (% by weight) of the monomer mixture used and the Mw, Mw / Mn and Tg of the obtained (meth) acrylic resin are summarized in Table 5.

The abbreviations in the "Monomer Composition" column of Table 5 mean the following monomers.
BA: n-butyl acrylate,
EHA: 2-ethylhexyl acrylate,
MA: Methyl acrylate,
AA: Acrylic acid,
HEA: 2-hydroxyethyl acrylate,
PEA: 2-phenoxyethyl acrylate,
PEA2: 2- (2-phenoxyethoxy) ethyl acrylate,
BMAM: N- (butoxymethyl) acrylamide.

<Examples 11 to 26>
(1) Preparation of Adhesive Composition With respect to 100 parts by weight of the solid content of the (meth) acrylic resin (A) obtained in the above production example, the cross-linking agent (B), compound (C) and ions shown in Table 6 are used. The sex compound (D) and the silane compound (E) are mixed in the amounts (parts by weight) shown in Table 6, and ethyl acetate is further added so that the solid content concentration becomes 14% by weight to prepare a solution of the pressure-sensitive adhesive composition. Was prepared. When the product used contains a solvent or the like, the blending amount of each blended ingredient shown in Table 6 is the number of parts by weight as the active ingredient contained therein.

Details of each compounding ingredient shown by abbreviation in Table 6 are as follows.
B1: Ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%), "Coronate L" obtained from Nippon Polyurethane Industry Co., Ltd.,
C1: Sodium acetate: Obtained from Wako Pure Chemical Industries, Ltd. (The adhesive composition was dissolved in acetic acid to prepare a 3.3% by weight solution and added).
C2-1: "AM-130G" obtained from Shin Nakamura Chemical Industry Co., Ltd. (the following formula:

Methoxylated polyethylene glycol acrylate represented by),
C2-2: "M-130G" obtained from Shin Nakamura Chemical Industry Co., Ltd. (the following formula:

Represented by methoxylated polyethylene glycol methacrylate),
D1: N-octyl-4-methylpyridinium hexafluorophosphate,
S1: 3-glycidoxypropyltrimethoxysilane, "KBM403" obtained from Shin-Etsu Chemical Co., Ltd.

(2) Preparation of Adhesive Layer A release film made of a polyethylene terephthalate film that has been subjected to a mold release treatment, each of the adhesive compositions prepared in (1) above [“PLR-382501” obtained from Lintec Co., Ltd., The release-treated surface of [referred to as a separator] was coated with an applicator so that the thickness after drying was 20 μm, and dried at 100 ° C. for 1 minute to prepare an adhesive layer (adhesive sheet).

(3) Preparation of Polarizing Plate with Adhesive Layer A first protective film made of the thermoplastic resin shown in Table 7 is adhered to one surface of a 23 μm-thick polarizer in which iodine is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film. A polarizing plate was produced by laminating via an agent and then laminating a second protective film made of (meth) acrylic resin on the other surface using an adhesive different from the above. Next, the outer surface of the first protective film was subjected to corona treatment once under the conditions of an output of 0.3 kW and a line speed of 10 m / min. Next, a surface (adhesive layer surface) opposite to the separator in the pressure-sensitive adhesive layer prepared in (2) above was bonded to the corona-treated surface by a laminator, and then the temperature was 23 ° C. and the relative humidity was 65%. After curing, a polarizing plate with an adhesive layer was obtained.

The abbreviations described in the "Protective film" column of Table 7 mean the following thermoplastic resins.
CO: Cyclic polyolefin resin (contact angle change rate based on the above definition: 56.3%),
AC: (meth) acrylic resin (contact angle change rate based on the above definition: 17.2%).

(4) Evaluation of Durability After peeling off the separator from the polarizing plate with an adhesive layer produced in (3) above, the adhesive layer surface is placed on both sides of a glass substrate for a liquid crystal cell [“Eagle XG” manufactured by Corning Inc.]. An evaluation sample was prepared by pasting so as to form a cross Nicol. The following three types of durability tests were carried out using this sample.
[Durability test]
-Heat resistance test that holds for 1000 hours under dry conditions at a temperature of 80 ° C.
Moisture resistance test that keeps for 1000 hours in an environment with a temperature of 60 ° C and a relative humidity of 90%.
A heat shock resistance (HS) test in which the operation of holding for 30 minutes under a dry condition at a temperature of 70 ° C. and then holding for 30 minutes under a dry condition at a temperature of -40 ° C. is set as one cycle, and this is repeated for 500 cycles.

The sample after each test was visually observed, and the durability was evaluated according to the following evaluation criteria. The results are shown in Table 7.

A: No change in appearance such as floating, peeling, foaming, etc.
B: There is almost no change in appearance such as floating, peeling, and foaming.
C: Many changes in appearance such as floating, peeling, and foaming are observed.
D: Appearance changes such as floating, peeling, and foaming are noticeably observed.

(5) Evaluation of Peeling Force of Optical Member with Adhesive Layer A test piece having a width of 25 mm and a length of 150 mm was cut from the polarizing plate with an adhesive layer produced in (3) above. Next, after peeling off the separator from this test piece, the pressure-sensitive adhesive layer surface was subjected to a glass substrate for a liquid crystal cell [trade name "EAGLE XG", Corning) by a sticking device [trade name "Lamipacker" manufactured by Fujipla Co., Ltd.]. Obtained from the company and attached to a non-alkali glass plate]. The obtained test piece to which the glass substrate was attached (optical member with an adhesive layer to which the glass substrate was attached) was placed in an autoclave at a temperature of 50 ° C. and a pressure of 5 kgf / cm ² (490.3 kPa) for 20 minutes. Pressurized. Further, it was allowed to stand in an atmosphere having a temperature of 23 ° C. for 24 hours and in an atmosphere having a temperature of 50 ° C. for 48 hours. The sample after standing is chucked in a tensile tester [“AUTOGRAPH AGS-X” manufactured by Shimadzu Corporation], and the tensile speed is 300 mm / min in an environment of a temperature of 23 ° C. and a relative humidity of 55%. It peeled off in the 180 ° direction. The peel strength measured at this time was evaluated as the peel strength. Here, the peeling force under the condition of storing for 24 hours in an atmosphere of a temperature of 23 ° C. is P23, and the peeling force under the condition of storing for 48 hours in an atmosphere of a temperature of 50 ° C. is P50. The results are shown in Table 7.

1 Polarizer, 2 surface treatment layer, 3, 4 protective film, 7 retardation film, 8 interlayer adhesive, 10 polarizing plate, 20 adhesive layer, 25 polarizing plate with adhesive layer, 30 glass substrate.

Claims (15)

A (meth) acrylic resin containing a structural unit derived from a (meth) acrylic monomer having a hydroxyl group, having a content of 3.5% by weight or less and a glass transition temperature of -25 ° C or less. A) 100 parts by weight and
Aromatic isocyanate-based cross-linking agent (B) 0.3 to 1 part by weight and
At least one compound (C) selected from the organic acid salt (C-1) and the compound (C-2) containing an alkyleneoxy group, and
Contains,
The organic acid salt (C-1) is composed of a carboxylate anion and a counter cation.
The counter cation is a metal ion or a cation having a heterocyclic structure, and is
The compound (C-2) containing an alkyleneoxy group is a compound represented by the following formula (C-2a).

[In the formula, h represents an integer of 1 to 6, Q ¹ represents a hydrogen atom or a methyl group, and Q ⁰ is a group represented by Q ⁰¹ , Q ⁰³ and Q ⁰⁴ below . ]

[During the ceremony,
In Q ⁰¹ , Q ² represents an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group which may be substituted with an alkoxy group having 1 to 3 carbon atoms, and L represents a single bond or 1 to 4 carbon atoms. Represents the alkylene group of, and i represents an integer of 1 to 50.
In Q ⁰³ , y and z each independently represent an integer of 1 to 40.
In ^Q04 , e, f, and g each independently represent an integer of 1 to 20. ]
When the organic acid salt (C-1) is contained, the content thereof is 0.0001 to 1 part by weight with respect to 100 parts by weight of the (meth) acrylic resin (A).
When the compound (C-2) containing an alkyleneoxy group is contained, the content thereof is 0.1 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A). Composition. The pressure-sensitive adhesive composition according to claim 1, wherein the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 0.5% by weight or more. The pressure-sensitive adhesive composition according to claim 1 or 2 , further containing the ionic compound (D) (except when the ionic compound (D) is the organic acid salt (C-1)). .. Further containing the ionic compound (D),
The carboxylate anion of the organic acid salt (C-1) does not contain a fluorine atom.
The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the anion of the ionic compound (D) contains a fluorine atom. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, further containing the silane compound (E). The pressure-sensitive adhesive composition is formed into layers on a film made of a cyclic polyolefin resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate and stored for 24 hours in an environment at a temperature of 23 ° C. The peeling force when peeling from the alkaline glass plate is P (CO) 23.
The pressure-sensitive adhesive composition is formed into layers on a film made of a cyclic polyolefin resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate and stored for 48 hours in an environment at a temperature of 50 ° C. The ratio of the P (CO) 50 to the P (CO) 23 (P (CO) 50 / P (CO) 23), where the peeling force when peeling from the alkaline glass plate is P (CO) 50. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the pressure is 3.2 or more. The pressure-sensitive adhesive composition is formed into layers on a film made of a (meth) acrylic resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate and stored for 24 hours in an environment at a temperature of 23 ° C. The peeling force when peeling from the non-alkali glass plate is P (AC) 23.
The pressure-sensitive adhesive composition is formed into layers on a film made of a (meth) acrylic resin, and the layered pressure-sensitive adhesive composition is laminated on a non-alkali glass plate and stored for 48 hours in an environment at a temperature of 50 ° C. The ratio of the P (AC) 50 to the P (AC) 23 (P (AC) 50 / P (AC), where the peeling force when peeling from the non-alkali glass plate is P (AC) 50. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein 23) is 3.2 or more. Containing the organic acid salt (C-1) and the compound (C-2) containing the alkyleneoxy group,
The content of the organic acid salt (C-1) is 0.0001 to 0.1 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A).
Any of claims 1 to 7, wherein the content of the compound (C-2) containing an alkyleneoxy group is 0.1 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A). The pressure-sensitive adhesive composition according to item 1. A pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition according to any one of claims 1 to 8. An optical member with an adhesive layer, which comprises an optical member and the adhesive layer according to claim 9 which is laminated on the optical member. The optical member with an adhesive layer according to claim 10, wherein the surface of the optical member on which the pressure-sensitive adhesive layer is laminated has a contact angle change rate of 40% or less when corona treatment is performed. The optical member includes a polarizer and a protective film laminated on the polarizer.
The optical member with an adhesive layer according to claim 11, wherein the surface is the surface of the protective film. The optical member with an adhesive layer according to claim 11 or 12, wherein the surface is a corona-treated surface. The optical member with an adhesive layer according to any one of claims 10 to 13, further comprising a glass substrate laminated on the adhesive layer. An optical member with an adhesive layer having a resin film and an adhesive layer laminated on at least one surface of the resin film.
The pressure-sensitive adhesive layer contains the pressure-sensitive adhesive composition according to any one of claims 1 to 8.
The peeling force when peeling from the non-alkali glass plate after being stored for 24 hours in an environment of a temperature of 23 ° C. in a state of being laminated on the non-alkali glass plate by the adhesive layer was defined as P23.
P50 and P23 when the peeling force when peeling from the non-alkali glass plate after being stored for 48 hours in an environment of a temperature of 50 ° C. in a state of being laminated on the non-alkali glass plate by the pressure-sensitive adhesive layer is P50. An optical member with an adhesive layer having a ratio (P50 / P23) of 3.2 or more.

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