KR20150140706A - Adhesive agent and adhesive sheet production using same - Google Patents

Abstract

The present invention relates to a pressure-sensitive adhesive composition which is excellent in re-releasability and which is hardly lifted or peeled off from an adherend, such as glass or plastic after exposure to a high-temperature environment or a high temperature and high humidity environment, To provide a pressure-sensitive adhesive capable of forming a sheet. (A) having no hydroxyl group and having a carboxyl group, an acrylic polymer (B) having a hydroxyl group without a carboxyl group, and at least one compound selected from an epoxy compound, a metal chelate compound and an aziridine compound and a polyisocyanate compound Adhesive

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-

The present invention relates to a pressure-sensitive adhesive which can be used for members such as plastics and glass.

2. Description of the Related Art Display devices such as liquid crystal displays used in various devices such as electronic calculators, electronic clocks, mobile phones, televisions, and the like have been on the increase in size, and liquid crystal TVs and plasma TVs are particularly large in size. In addition, recently, touch panel type liquid crystal displays including smart phones and tablets are rapidly spreading, and a large market expansion is expected in the future. On the other hand, it is also used for automobile devices such as LCD display and car navigation, and is required to have durability that can be used in a harsh vehicle environment such as a high temperature and high humidity atmosphere. A polarizing plate or a retardation plate having various optical functions is used for a liquid crystal display, and they are attached to a skin complex such as a liquid crystal cell using glass or transparent plastic through a pressure-sensitive adhesive.

The polarizing plate is generally a laminate in which a polyvinyl alcohol film is surrounded by a triacetylcellulose film or a cycloolefin-based film. Since these films have different mechanical properties, the rate of dimensional change at the time of heating is different. Therefore, when the film is placed under a high-temperature atmosphere, deformation often occurs in the laminate.

Here, when a laminate of, for example, a polarizer / pressure-sensitive adhesive layer / glass (surface member of a liquid crystal cell) is left in a high-temperature atmosphere, if deformation due to a dimensional change rate between constituent members of the polarizer occurs, (Bubble) is generated at the adhesive interface of the polarizing plate, and the polarizing plate is lifted and peeled from the glass. As a result, the stress distribution in the laminate becomes uneven and the stress concentrates on the peripheral edge portion of the laminate. As a result, light leaks from the edges and peripheral edges of the laminate, The same problem occurs in a high temperature and high humidity environment.

On the other hand, in a manufacturing process of a liquid crystal display or the like, when a polarizing plate is attached to an optical component such as a liquid crystal cell, or when a difference occurs at an alignment position, the polarizing plate is peeled off after a certain period of time from alignment, So that the liquid crystal cell can be reused. Therefore, a function (rework) of releasing a polarizing plate from a liquid crystal cell after a lapse of time from the time of adhesion has been demanded in the pressure-sensitive adhesive.

In order to solve such a problem, Patent Document 1 discloses a technique in which a pressure-sensitive adhesive plasticizer or the like is added in order to solve a light leakage problem, moderately softening the pressure-sensitive adhesive layer and imparting stress relaxation property.

Patent Document 2 discloses a technique for enhancing stress relaxation property of a coating film including an acrylic copolymer using an aromatic ring-containing monomer for imparting stress relaxation property to prevent light leakage.

On the other hand, Patent Document 3 discloses a technique of mixing a low molecular weight acrylic polymer having a high acid value and a weight average molecular weight of 0.2 to 100,000 with respect to a molecular weight acrylic polymer having a weight average molecular weight of 500,000 or more in order to impart re-

Patent Document 4 discloses a technique for increasing the stress relaxation property by using a combination of an acrylic polymer having a carboxyl group and a weight average molecular weight of 700,000 or more and an acrylic copolymer having a weight average molecular weight of 800 to 50,000.

Patent Document 5 discloses a technique for obtaining a sufficient cohesive force by using an acrylic copolymer having a hydroxyl group and an acrylic copolymer containing a monomer having a Tg of 60 ° C or higher and a (meth) acrylic acid ester.

Patent Document 1: JP-A-9-87593 Patent Document 2: Japanese Patent Application Laid-Open No. 2007-169329 Patent Document 3: JP-A-2010-100710 Patent Document 4: Japanese Patent No. 4136524 Patent Document 5: Japanese Patent No. 4788937

However, when a plasticizer is added to a conventional pressure-sensitive adhesive, the pressure-sensitive adhesive tends to bleed out to contaminate the skin complex when peeling off the polarizing plate, and the cohesive force is lowered. . Further, there has been a problem that whitening of the coating film occurs due to the addition of excess plasticizer.

Further, the pressure-sensitive adhesive using an aromatic ring-containing monomer has a problem in that a white spot is generated in the light leakage evaluation and optical characteristics are deteriorated.

In addition, the pressure-sensitive adhesive using a copolymer having a different weight average molecular weight by using hydrogen peroxide was not practical because the drying condition of the pressure-sensitive adhesive was limited.

Further, the pressure-sensitive adhesive using a copolymer having a different weight average molecular weight without using a peroxide has a problem that the cohesive force is markedly lowered by a copolymer having a low molecular weight.

In addition, a pressure-sensitive adhesive compounded with a copolymer having a high Tg in a general copolymer has a good cohesive force, but has a problem that whitening occurs due to insufficient stress relaxation property.

INDUSTRIAL APPLICABILITY The present invention is excellent in peelability when used in an adhesive film, and is not liable to be lifted or peeled off from a skin complex even after exposure to a high temperature environment or a high temperature and high humidity environment, And to provide a pressure-sensitive adhesive capable of forming an adhesive layer which does not occur.

(A) having no hydroxyl group and having a carboxyl group, an acrylic polymer (B) having no hydroxyl group and a hydroxyl group, at least one compound selected from an epoxy compound, a metal chelate compound and an aziridine compound and a polyisocyanate compound .

According to the present invention constituted as described above, the pressure-sensitive adhesive layer formed in the pressure-sensitive adhesive has a crosslinking reaction with the carboxyl group of the acrylic copolymer (A) and at least one compound selected from an epoxy compound, a metal chelate compound and an aziridine compound, (B) is crosslinked with the polyisocyanate compound. The pressure-sensitive adhesive layer does not lose cohesive strength and is excellent in stress relaxation. Therefore, when the pressure-sensitive adhesive layer is left in a high-temperature atmosphere or a high-temperature and high-humidity atmosphere, the pressure-sensitive adhesive layer hardly causes lifting and peeling, light leakage, and indentation on the pressure-sensitive adhesive layer.

According to the present invention, it is possible to provide a pressure-sensitive adhesive which is excellent in re-peeling property and is difficult to peel off or peel off from an adherend, such as glass or plastic, exposed to a high temperature environment or high temperature and high humidity environment, It is possible to provide a pressure-sensitive adhesive capable of forming a sheet.

The pressure-sensitive adhesive of the present invention is a pressure-sensitive adhesive comprising at least one compound selected from the group consisting of an acrylic polymer (A) having no hydroxyl group and a carboxyl group, an acrylic polymer (B) having no carboxyl group and having a hydroxyl group and an epoxy compound, a metal chelate compound and an aziridine compound Compounds, and polyisocyanate compounds. The pressure-sensitive adhesive of the present invention is preferably used as an adhesive tape having a pressure-sensitive adhesive layer formed by coating and drying. The adhesive tape is preferably used for bonding an optical member, particularly a member of a liquid crystal display.

In the present invention, the acrylic polymer (A) and the acrylic polymer (B) are copolymers of monomers containing (meth) acrylic acid esters. The acrylic polymer (A) and the acrylic polymer (B) each form a polymer network by a cross-linking reaction to obtain an effect of suppressing lifting and peeling, light leakage, and indentation. Further, in the present invention, the (meth) acrylic acid ester includes an acrylate ester and a methacrylate ester.

In the present invention, the acrylic polymer (A) is a polymer having a hydroxyl group and a carboxyl group. Concretely, it is necessary to copolymerize a monomer mixture containing a monomer having a hydroxyl group as a reactive functional group and a monomer having a carboxyl group. Examples of the monomer containing a carboxyl group include (meth) acrylic acid, phthalic acid monohydroxyethyl acrylate, p-carboxymethylbenzyl acrylate, ethylene oxide modified (addition molar: 2 to 18) phthalic acid acrylate, phthalic acid monohydroxy Maleic acid monoethyl maleate, itaconic acid, citraconic acid, fumaric acid, and the like can be used in combination with one or more of (meth) acrylic acid esters such as ethyl acrylate, propyl acrylate, succinic acid monohydroxyethyl acrylate, . These may be used alone or in combination of two or more.

The polymer having a carboxyl group is preferably contained in an amount of 0.01 to 20% by weight, more preferably 0.5 to 15% by weight, based on 100% by weight of the monomer mixture. The cohesive force is further improved by the content of 0.01% or more. Further, the content becomes 20 wt% or less, so that the cohesive force and the stress relaxation property are both easily obtained.

The acrylic copolymer (B) of the present invention is a polymer having no hydroxyl group and having no carboxyl group. Specifically, it is necessary to copolymerize a monomer mixture containing a monomer having a carboxyl group as a reactive functional group and containing a monomer having a hydroxyl group.

Examples of the monomer containing a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (Meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl Glycol mono (meth) acrylic acid esters such as polyethylene glycol mono (meth) acrylic acid esters, polypropylene glycol mono (meth) acrylic acid esters and 1,4-cyclohexanedimethanol mono (meth) acrylic acid esters; caprolactone- Acrylic ester, hydroxyethyl acrylamide, and the like. Of these, 4-hydroxybutyl (meth) acrylate 2-hydroxyethyl (meth) acrylate is preferable. These may be used alone or in combination of two or more.

The monomer having a hydroxyl group is preferably contained in an amount of 0.01 to 20% by weight, more preferably 0.2 to 15% by weight, based on 100% by weight of the monomer mixture. The cohesive force is further improved by the content of 0.01% or more. Further, the content becomes 20 wt% or less, so that the cohesive force and the stress relaxation property can be easily achieved at the same time.

Monomers usable for copolymerization of the acrylic polymer (A) and the acrylic polymer (B) are preferably (meth) acrylic acid alkyl esters and other vinyl monomers.

Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (Meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, (meth) acrylate, isobutyl (meth) acrylate, isobutyl Decyl acrylate, and the like. Among these, butyl (meth) acrylate is preferable in that good adhesion performance can be easily obtained. These may be used alone or in combination of two or more.

The amount of the (meth) acrylic acid alkyl ester monomer mixture is preferably 5 to 50% by weight, more preferably 10 to 30% by weight, based on 100% by weight of the mixture. When the content is 5% or more, cohesion is further improved. Further, the content becomes 50 wt% or less, so that the cohesive force and the stress relaxation property can be easily achieved at the same time.

The other vinyl monomer is preferably a monomer containing an amide bond, a monomer containing an epoxy group, a monomer containing an amino group, a monomer having an alkylene oxide unit, vinyl acetate, vinyl crotonate, styrene, acrylonitrile, It is not particularly limited to these.

The amide bond-containing monomer may be, for example, (meth) acrylamide, N-methylacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, (Meth) acrylamide compounds such as N-dimethylaminopropyl (meth) acrylamide, diacetone acrylamide, N- (hydroxymethyl) acrylamide and N- (butoxymethyl) acrylamide, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, and the like can be given.

Examples of the monomer containing an epoxy group include glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, , 4-epoxycyclohexylmethyl, and the like.

Examples of the monomer containing an amino group include (meth) acrylate monomethylaminoethyl, (meth) acrylate monoethylaminoethyl, (meth) acrylate monomethylaminopropyl, (meth) acrylate monoethylaminopropyl And (meth) acrylate monoalkylamino esters such as (meth) acrylate.

The monomer having an alkylene oxide unit preferably has units such as ethylene oxide and propylene oxide. Specific examples thereof include 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-phenoxyethyl acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) Ethoxypolypropylene glycol (meth) acrylate ester, phenoxypolyethylene glycol (meth) acrylate ester, phenoxypolypropylene glycol (meth) acrylate ester, and the like.

These vinyl monomers may be used singly or in combination of two or more of these monomers.

The other vinyl monomer preferably comprises 5 to 30% by weight, more preferably 10 to 25% by weight, based on 100% by weight of the monomer mixture. When the content is 5% or more, cohesion is further improved. Further, when the content is less than 30 parts by weight, the cohesive force and the stress relaxation property are both easily obtained.

The pressure sensitive adhesive of the present invention preferably contains the acrylic copolymer (A) and the acrylic polymer (B) in a weight ratio of (A) / (B) = 95/5 to 5/95, and (A) / / 10 to 10/90, and more preferably (A) / (B) = 90/10 to 50/50. The total amount of the acrylic polymer (A) and the acrylic polymer (B) is 90% by weight or less, the cohesive strength is further improved. When the acrylic polymer (B) is contained in an amount of 90% by weight or less, the stress relaxation property is further improved. In the present invention, the mixing ratio of the acrylic copolymer (A) and the acrylic polymer (B) is important, and the acrylic copolymer (A) and the acrylic polymer (B) 95 weight ratio, it is possible to suppress the light leakage and suppress the peeling and peeling of the polarizing plate.

The acrylic copolymer (A) in the pressure-sensitive adhesive of the present invention preferably has a weight average molecular weight of 500,000 to 2,000,000. It is in the range of 500,000 to 2,000,000, and the cohesion and the like are further improved, so that it is possible to further suppress the lifting and peeling, and further improve the stress relaxation property.

The weight average molecular weight of the acrylic polymer (B) is preferably 100,000 to 1,000,000. Since it is in the range of 100,000-1,000,000, the cohesive force is further improved, so that it is possible to further suppress the exfoliation and peeling, and the stress relaxation property is further improved. The molecular weight distribution (molecular weight distribution (Mw / Mn) showing the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn)) when the acrylic copolymers (A) and (B) are mixed is 2 to 20 desirable. In the above range, lifting and peeling are less likely to occur and the adhesive force is further improved. The weight average molecular weight and the number average molecular weight are polystyrene reduced values measured by a gel permeation chromatography (GPC) method. Details of the GPC measurement method are described in Examples.

The acrylic copolymer (A) and the acrylic polymer (B) of the present invention can be obtained by radical polymerization of a monomer mixture in a radical polymerization initiator. The radical polymerization can be carried out by known polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization and suspension polymerization, but solution polymerization is preferred in the present invention. The solvent which can be used in solution polymerization is preferably acetone, methyl acetate, ethyl acetate, toluene, xylene, anisole, methyl ethyl ketone, cyclohexanone and the like. The polymerization temperature is preferably a boiling point of 60 to 120 占 폚, and the polymerization time is preferably 5 to 12 hours.

The radical polymerization initiator is not particularly limited as long as it is a compound capable of generating a radical at the polymerization temperature, and known compounds such as peroxide and azo compound can be used. Butyl peroxides such as di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide,?,? '- bis (t- butylperoxy- Dialkyl peroxides such as di (t-butylperoxy) hexyne-3;

peroxy esters such as t-butyl peroxybenzoate, t-butyl peroxyacetate and 2,5-dimethyl-2,5-di (benzoyl peroxy) hexane;

Ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide;

Propane, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis ( butylperoxy) cyclohexane, and n-butyl-4,4-bis (t-butylperoxy) valerate;

Hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide and 2,5-dimethylcyclohexane-2,5-dihydroperoxide;

Diacyl peroxides such as benzoyl peroxide, decanoyl peroxide, lauroyl peroxide and 2,4-dichlorobenzoyl peroxide;

And organic peroxides such as peroxydicarbonates such as bis (t-butylcyclohexyl) peroxydicarbonate, or mixtures thereof.

Examples of the azo compound include 2,2'-azobisbutynitrile such as 2,2'-azobisisobutyronitrile (abbreviation: AIBN) and 2,2'-azobis (2-methylbutyronitrile) Nitriles;

Azobisvalere such as 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) and 2,2'-azobis (2,4-dimethylvaleronitrile) Nitriles;

2,2'-azobispropionitrile such as 2,2'-azobis (2-hydroxymethylpropionitrile);

And 1,1'-azobis-1-alkanenitriles such as 1,1'-azobis (cyclohexane-1-carbonitrile).

The radical polymerization initiator may be used alone or in combination of two or more.

The radical polymerization initiator is preferably used in an amount of 0.01 to 10 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the monomer mixture.

As the pressure-sensitive adhesive of the present invention, it is preferable to use a curing agent which reacts with a reactive functional group of the acrylic copolymer (A), and a curing agent which reacts with a reactive functional group of the acrylic copolymer (B). A crosslinking network of the acrylic polymer (A) and a crosslinking network of the acrylic polymer (B) are mutually intertwined with each other, and a portion which intercalates with a portion existing independently exists, so that excellent cohesive strength and good stress relaxation property are obtained.

The curing agent which reacts with the acrylic polymer (A) having a carboxyl group is preferably an epoxy compound, a metal chelate compound, an aziridine compound, an acid anhydride group-containing compound, a carbodiimide compound and an N-methylol group-containing compound. The curing agent which reacts with the acrylic polymer (B) having a hydroxyl group is preferably a polyisocyanate compound. Further, the acrylic polymer (A) curing agent is preferably one of an epoxy compound, a metal chelate compound and an aziridine compound, because the cohesive force and the stress relaxation property are further improved.

The epoxy compound may be, for example, bisphenol A-epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6 - hexanediol diglycidyl ether, trimethylol propane triglycidyl ether, diglycidyl aniline, N, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis , N'-diglycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidylaminophenylmethane and the like.

Examples of the metal chelate compound include a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium, acetylacetone or acetoacetic acid ethyl and coordination compounds have. Specific examples include aluminum ethylacetoacetate diisopropylate, aluminum trisacetylacetonate, aluminum bis ethylacetoacetate and monoacetylacetonate, and aluminum alkyl acetoacetate diisopropylate.

The aziridine compound may be, for example, N, N'-diphenylmethane-4,4'-bis (1-aziridine carboxamide), N, N'- Aziridinylphosphine oxide, N, N'-hexamethylene-1,6-bis (1-aziridine (2-methylaniline) Tris [3- (1-aziridinyl) propionate, trimethylol propane tri- beta -aziridinyl propionate, tetramethylol methane tri tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, 4,4'-bis (ethyleneiminocarbonylamino) di Phenyl methane and the like.

The carbodiimide compound is a high molecular weight polycarbodiimide produced by a decarboxylic acid condensation reaction of a diisocyanate compound in the presence of a carbodiimidization catalyst. Examples of such a high molecular weight polycarbodiimide include Carbodite series of Nippon Express Co., Ltd. Of these, carboditlite V-01, 03, 05, 07 and 09 are preferred because of their excellent compatibility with organic solvents.

The acid anhydride group-containing compound is a compound having two or more carboxylic acid anhydride groups and is not particularly limited, and examples thereof include tetracarboxylic acid dianhydride, hexacarboxylic acid tri anhydride, hexacarboxylic acid dianhydride, maleic anhydride copolymer resin . In addition, polycarboxylic acids, polycarboxylic acid esters, polycarboxylic acid half esters and the like that can become anhydrides through dehydration reaction during the reaction are included in the "acid anhydride group-containing compound" of the present invention.

The tetracarboxylic acid dianhydride may be, for example, an anhydride of pyromellitic acid, benzophenonetetracarboxylic acid dianhydride, biphenyltetracarboxylic acid dianhydride, oxydiphthalic anhydride, diphenylsulfone tetracarboxylic acid dianhydride, Diphenylsulfide tetracarboxylic acid dianhydride, butane tetracarboxylic acid dianhydride, perylenetetracarboxylic acid dianhydride, and naphthalenetetracarboxylic acid dianhydride.

In the present invention, the polyisocyanate compound is an isocyanate monomer having two or more isocyanate groups, specifically, an isocyanate monomer such as an aromatic polyisocyanate, an aliphatic polyisocyanate, an aromatic aliphatic polyisocyanate, an alicyclic polyisocyanate and the like and a burette, nurate bodies and adduct bodies are preferable.

Examples of the aromatic polyisocyanate include 1,3-phenylene isocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene isocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- Tolylene diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diisocyanate diisocyanate, 2,6-tolylene diisocyanate, '-Diphenyl diisocyanate, 4,4', 4 "-triphenylmethane triisocyanate, and the like.

The above aliphatic polyisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (aka: HMDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate , 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

The aromatic aliphatic polyisocyanate may be, for example, ω, ω'-diisocyanate-1,3-dimethylbenzene, ω'-diisocyanate-1,4-dimethylbenzene, ω, ω'-diisocyanate- 4-diethylbenzene, 1,4-tetramethylxylene diisocyanate, 1,3-tetramethylxylene diisocyanate, and the like.

The alicyclic polyisocyanate may be, for example, 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (IPDI, isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3- Diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylene bis (cyclohexyl isocyanate) - bis (isocyanatomethyl) cyclohexane and the like.

The burette body refers to a self-condensate having biuret bonds in which the isocyanate monomer is self-condensed. Specific examples thereof include buret resin of hexamethylene diisocyanate and the like.

The nylon body refers to a trimer of the isocyanate monomer, and examples thereof include a trimer of trimer isomer of isomer of isomer of hexamethylene diisocyanate, and a trimer of trimer isocyanate of isomer of isomer of hexamethylene diisocyanate.

The adduct is a bifunctional or higher isocyanate compound in which the isocyanate monomer is reacted with a bifunctional or higher functional low-molecular-weight hydrogen-containing compound. For example, a compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate A compound obtained by reacting trimethylol propane with isophorone diisocyanate, a compound obtained by reacting 1,6-hexanediol with hexamethylene diisocyanate, and the like, .

The above-mentioned bifunctional or higher functional low-molecular hydrogen-containing compound may be, for example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, Dimethyl-heptane, 2-methyl-1,8-octanediol, 3,3'-dimethylolheptane, 2-butyl- 10 or less), polyoxypropylene glycol (addition molar number of propylene oxide of 10 or less), 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Aliphatic or alicyclic alcohols such as nonanediol, neopentyl glycol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, cyclohexanedimethanol, tricyclodecane methanol, cyclopentadiene dimethanol, Group diols;

Benzene, 1,2-bis (2-hydroxyethoxy) benzene, 1,4-bis (2-hydroxyethoxy) benzene, 4,4'- Methylenediphenol, 4,4'- (2-norbornylidene) diphenol, 4,4'-dihydroxyphenol, o-, m- and p-hydroxybenzene, 4,4'-isopropylidene Aromatic diols such as bisphenols obtained by adding phenol or an alkylene oxide such as ethylene oxide or propylene oxide to bisphenols such as bisphenol A and bisphenol F;

1,1,1-trimethylolpropane, 1,1,1-trimethylolbutane, 1,1,1-trimethylol pentane, 1,1,1-trimethylolhexane, 1,1,1-trimethylolheptane, 1,1,1-trimethylolooctane, 1,1,1-trimethylolone, 1,1,1-trimethylol decane, 1,1,1-trimethylol dodecane, 1,1,1-trimethylol decane , 1,1,1-trimethylol tridecane, 1,1,1-trimethylol tetradecane, 1,1,1-trimethylol pentadecane, 1,1,1-trimethylol hexadecane, 1,1,1 Trimethylolheptadecane, 1,1,1-trimethylolooctadecane, 1,1,1-trimethylolanodecane, 1,1,1-trimethylol-sec-butane, 1,1,1-trimethylol- tert-pentane 1,1,1-trimethylol-tert-nonane, 1,1,1-trimethylol-tert-tridecane, 1,1,1-trimethylol-tert-heptadecane, Trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol- Ethyl-hexane, 1,1,1-trimethylol iso Trimethylolpropane, trimethylolpropane, trimethylolpropane, trimethylolpropane, trimethylolpropane, trimethylolpropane, trimethylolpropane, trimethylolpropane, trimethylolpropane, Trifunctional polyols such as pentadecene, trimethylolhexadecene, trimethylolheptadecene, trimethylolooctadecene, 1,2,6-butanetriol, 1,2,4-butanetriol and glycerin;

Pentaerythritol, dipentaerythritol, sorbitol, xylitol and the like;

But are not limited to, ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, hexylenediamine, octylenediamine, nonylenediamine, diaminodicyclohexylmethane, 3-aminomethyl-3,5,5-trimethylcyclo Aliphatic polyamines such as hexylamine, 1, 3-bis (aminomethyl) cyclohexane, triethylenetetramine, diethylenetriamine, and triaminopropane;

Aromatic polyamines such as phenylenediamine, triphenylenediamine, diaminodiphenylmethane and diaminodiphenyl ether;

But are not limited to, ethylene dithiol, propylene dithiol, butylenedithiol, pentylenedithiol, hexylenedithiol, heptylenedithiol, octylenedithiol, nonylenedithiol, dimercaptodicyclohexylmethane, Trimethylcyclohexylthiol, 1,3-bis (mercaptomethyl) cyclohexane, 1,4-bis (3-mercaptobutyryloxy) butane, pentaerythritol tetrakis (3- Mercaptobutyrate), and the like. These polyfunctional low molecular active hydrogen containing compounds may be used alone or in combination of two or more.

The polyisocyanate compound is preferably a trifunctional isocyanate compound from the viewpoint of forming a sufficient crosslinked structure, and more preferably an adduct which is a reaction product of an isocyanate monomer and a trifunctional low molecular active hydrogen-containing compound. Specific examples thereof include trimethylolpropane adduct of hexamethylene diisocyanate, trimethylol propane adduct of trilene diisocyanate, trimethylol propane adduct of isophorone diisocyanate, nylate of isophorone diisocyanate, A trimethylolpropane adduct of isocyanate, and more preferably a trimethylolpropane adduct of trilene diisocyanate and a nylon of isophorone diisocyanate. These polyisocyanate compounds may be used alone or in combination of two or more.

In the present invention, the curing agent which reacts with the reactive functional group of the acrylic polymer (A) is preferably used in an amount of 0.05 to 5% by weight, more preferably 0.1 to 3% by weight, based on 100 parts by weight of the acrylic copolymer (A).

In the present invention, the curing agent which reacts with the reactive functional group of the acrylic polymer (B) is preferably used in an amount of 1 to 50% by weight, more preferably 5 to 35% by weight, based on 100 parts by weight of the acrylic copolymer (B).

The pressure sensitive adhesive of the present invention preferably includes a silane coupling agent. By using a silane coupling agent, the adhesive force is further improved, so that the lifting and peeling can be further suppressed.

Examples of the silane coupling agent include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyltripropoxysilane, 3- An alkoxysilane compound having a (meth) acryloxy group such as (meth) acryloxypropyltripropoxysilane, 3- (meth) acryloxypropyltributoxysilane and 3- (meth) acryloxypropylmethyldiethoxysilane;

Alkoxysilane compounds having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane and vinylmethyldiethoxysilane;

Aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N- - (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane;

3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, etc. An alkoxysilane compound having a mercapto group;

3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3- Alkoxysilane compounds having an epoxy group such as methyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane;

Tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane and tetrabutoxysilane;

N-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, styryltrimethoxysilane, phenyl tri (1,3-dimethylbutylidene) propylamine, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanate, diphenyldimethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, silicone resin having an alkoxysilyl group in hexamethyldisilazane molecule, and the like.

The silane coupling agent is preferably used in an amount of 0.01 to 2 parts by weight, and more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the total of the acrylic copolymer (A) and the acrylic copolymer (A).

The pressure-sensitive adhesive of the present invention may contain various additives such as a tackifier resin, various resins, oils, softeners, dyes, pigments, antioxidants, ultraviolet absorbers, weatherability stabilizers plasticizers, fillers, antioxidants and antistatic agents May be blended.

The pressure-sensitive adhesive of the present invention is not only preferable as a pressure-sensitive adhesive for optical members, but also various kinds of plastic sheets, general label stickers, paints, elastic wall materials, coating films, flooring materials, tackifiers, pressure- (Rigid, semi-rigid, flexible), urethane RIM, UV / EB cured resin, high solid (such as a magnetic recording medium, an ink binder, a casting binder, a plastic brick binder, a graft material, a microcapsule or a glass fiber size) high elasticity microcellular paint, thermosetting elastic microcellular, textile processing, plasticizer, sound absorbing material, vibration damping material, surfactant, gelling agent, resin for artificial marble, impact resistance imparting agent for artificial marble, resin film for ink (laminating adhesive protective film, etc.) ), Resin for laminated glass, reactive diluent, various molding materials, elastic fibers, artificial leather, synthetic leather and the like, It can be very useful as a padding additive and raw materials thereof.

The pressure-sensitive adhesive sheet of the present invention comprises a substrate and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive of the present invention. The pressure-sensitive adhesive sheet is obtained, for example, by applying a pressure-sensitive adhesive on a substrate to form a pressure-sensitive adhesive layer. Further, a releasable sheet can be coated with a pressure-sensitive adhesive and dried to form a pressure-sensitive adhesive layer, and the substrates can be bonded together. The pressure-sensitive adhesive layer may be provided on at least one side of the substrate. In the present invention, the sheet, film and tape are synonymous. Needless to say, the releasable sheet is stuck to the surface of the pressure-sensitive adhesive layer not in contact with the base material.

When the pressure-sensitive adhesive is applied, it may be a suitable liquid medium, for example, a hydrocarbon solvent such as toluene, xylene, hexane or heptane; Ester solvents such as ethyl acetate and butyl acetate; Ketone solvents such as acetone and methyl ethyl ketone; Halogenated hydrocarbon solvents such as dichloromethane and chloroform; An organic solvent such as an ether solvent such as diethyl ether, methoxy toluene or dioxane, or other hydrocarbon solvent may be added to adjust the viscosity. Further, the viscosity may be lowered by heating the pressure-sensitive adhesive. However, it is preferable to avoid use of water, alcohol or the like in order to suppress the crosslinking reaction between the acrylic copolymer (B) and the polyisocyanate compound.

The substrate may be, for example, cellophane, plastic, rubber, foam, cloth, rubber cloth, resin impregnated fiber, glass, wood and the like. The substrate may be a plate or a film. It is also preferable that the substrate is a single substrate or a multilayer substrate.

Examples of the plastic include polyolefin resins such as polyvinyl alcohol and triacetyl cellulose, polypropylene, polyethylene, polycycloolefin and ethylene-vinyl acetate copolymer, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate (PAR is a copolymer resin of bisphenol A and phthalate), polyacrylic resin, polyphenylene sulfide resin, polystyrene resin, polyamide resin, polyamide resin A resin, a polyimide resin, an epoxy resin (a resin obtained by reacting an epoxy group-containing resin with a polyamine or a carboxylic anhydride), and the like.

In the present invention, the pressure-sensitive adhesive can be coated by a known method. For example, a meiya bar, a spatula, a brush, a spray, a roller, a gravure coater, a die coater, a lip coater, a comma coater, a knife coater, a reverse coater and a spin coater. The drying method is not particularly limited, and examples thereof include hot air drying, infrared light, and a decompression method. Drying conditions are usually heated to 60 ~ 160 ℃.

The thickness of the pressure-sensitive adhesive layer is preferably 0.1 to 300 占 퐉, more preferably 1 to 100 占 퐉. When the thickness is less than 0.1 탆, sufficient adhesive force may not be obtained, and when the thickness exceeds 300 탆, the performance such as adhesive strength is not improved more often.

Further, the adhesive film of the present invention preferably has an adhesive strength of 2 to 20 N / 25 mm, more preferably 2 to 15 N / 25 mm, after one day at 23 캜 after being applied to an alkali-free glass. Adhesive strength of 2N / 25 mm or more makes it easy to obtain a sufficient adhesive force that is hard to cause peeling and peeling. Further, since the adhesive force is 20 N / 25 mm or less, the skin complex can be more easily peeled off.

The storage elastic modulus (G ') of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention at 23 캜 is preferably 0.1 to 5 MPa. When the storage elastic modulus (G ') at 23 ° C is 0.1 MPa or more, the adhesive property is further improved. When the storage elastic modulus (G ') at 23 캜 is 5 MPa or less, the adhesive strength is further improved. The storage elastic modulus (G ') at 23 캜 is more preferably 0.1 to 2.0 MPa. The storage elastic modulus (G ') of the pressure-sensitive adhesive layer at 80 캜 is preferably 0.1 to 2 MPa. The storage elastic modulus (G ') at 80 캜 is 0.1 MPa or more, so that the lifting and peeling can be further suppressed in a high temperature atmosphere and a high temperature and high humidity atmosphere. Further, since the storage elastic modulus (G ') at 80 DEG C is 2 MPa or less, it is possible to further improve the adhesive force in a high temperature atmosphere and a high temperature and high humidity environment. The storage elastic modulus (G ') at 80 캜 is more preferably 0.1 to 1 MPa. Details of the method for measuring the storage elastic modulus (G ') will be described in Examples.

When a pressure-sensitive adhesive is applied to a base material to produce a pressure-sensitive adhesive sheet, it is general that the pressure-sensitive adhesive sheet is wound once and then processed such as cutting. Foreign matter such as dust or dust adhering to the outside from the outside can adhere to the pressure-sensitive adhesive sheet during the processing, and the foreign matter can leave traces (referred to as indentations in the present invention) on the pressure-sensitive adhesive layer. Particularly, when a polarizing plate is used as a substrate, a step of cutting the pressure-sensitive adhesive sheet to a desired size and polishing the end to smooth it is performed. Since the indentation is likely to occur during the above process, the yield is remarkably lowered. In the pressure-sensitive adhesive of the present invention, the storage elastic modulus (G ') at 23 ° C of the pressure-sensitive adhesive layer is 0.1 to 5 MPa, so that occurrence of indentation at the production of the pressure-sensitive adhesive sheet can be further suppressed. The storage elastic modulus (G ') is 0.1 MPa or more, so that the indentation can be further suppressed. When the pressure is 5 MPa or less, the adhesive strength can be further improved.

The adhesive sheet of the present invention can be suitably used for adhesion of optical members. That is, it is preferable to use an optical member on a substrate. Specific examples of the optical member include a polarizing plate, a retardation film, an elliptically polarizing film, an antireflection film, and a brightness enhancement film.

It is also preferable that the pressure-sensitive adhesive sheet of the present invention using an optical member on a substrate is used as a liquid crystal cell member by attaching it to a glass member of a liquid crystal cell. When the optical member is a polarizing plate, even when the polarizing plate is left in a high-temperature atmosphere and a high-temperature and high-humidity atmosphere, the pressure-sensitive adhesive layer has good stress relaxation property, and therefore light leakage due to bending of the polarizing plate can be suppressed.

The pressure-sensitive adhesive sheet of the present invention can be suitably used for various electronic-related members such as LCD, plasma display, and touch panel electrode peripheral members, protective films, building materials, and glass members such as glass windows for automobiles. , Wood, plywood, stainless steel, and aluminum.

Example

Next, embodiments of the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto. In the examples, "part" means "part by weight" and "%" means "% by weight", respectively.

≪ Synthesis Example 1: Acrylic copolymer (A) >

99.5 parts of butyl acrylate, 0.5 part of acrylic acid, 100 parts of ethyl acetate, 2 parts of 2,2'-dicyclohexylcarbodiimide were added to a reaction vessel (hereinafter referred to as "reaction vessel") equipped with a stirrer, a thermometer, a reflux condenser, 0.025 part of azobisisobutyronitrile (hereinafter referred to as AIBN) was prepared, and air in the reaction vessel was replaced with nitrogen gas. Thereafter, the reaction was started by heating to 80 DEG C while stirring in a nitrogen atmosphere. Thereafter, the reaction solution was allowed to react at the reflux temperature for 7 hours. After completion of the reaction, the reaction mixture was cooled, diluted with ethyl acetate, and a nonvolatile matter content of 30% and a viscosity of 3000 m (Mw) were measured. As a result, the weight average molecular weight was 1 million. The obtained copolymer is referred to as copolymer (A-1).

≪ Synthesis Examples 2 to 20 &

Various raw materials were prepared according to the weight ratios in Table 1, and an acrylic copolymer (A) was synthesized in the same manner as in Synthesis Example 1. [ Table 1 shows the weight average molecular weights of the obtained acrylic copolymers.

Synthesis Example 21: Acrylic copolymer (B)

99.8 parts of butyl acrylate, 0.2 parts of 2-hydroxyethyl acrylate, 100 parts of ethyl acetate and 0.025 part of AIBN were prepared in a reaction vessel, and the air in the reaction vessel was replaced with nitrogen gas. Thereafter, the reaction was started by heating to 80 DEG C while stirring in a nitrogen atmosphere. Thereafter, the reaction solution was allowed to react at the reflux temperature for 7 hours. After completion of the reaction, the reaction mixture was cooled and diluted with ethyl acetate to obtain a copolymer solution having a nonvolatile content of 30% and a viscosity of 3000 mPa.s. The weight average molecular weight (Mw) of the acrylic copolymer was measured using GPC, and the weight average molecular weight was 1 million. The obtained copolymer is referred to as copolymer (B-1).

≪ Synthesis Examples 22 to 40 &

Various raw materials were prepared in accordance with the weight ratios in Table 2, and an acrylic copolymer (B) was synthesized in the same manner as in Synthesis Example 21. Table 2 shows the weight average molecular weights of the obtained acrylic copolymers.

[Table 1]

[Table 2]

≪ Measurement of weight average molecular weight (Mw)

The weight-average molecular weight (Mw) was measured using a GPC "LC-GPC system" manufactured by Shimadzu Corporation. GPC is a liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified by a difference in molecular size, and a weight average molecular weight (Mw) is determined in terms of polystyrene.

Device name: manufactured by Shimadzu Corporation, LC-GPC system "Prominence"

Column: four GMHXLs manufactured by Tosoh Corporation, and one HXL-H manufactured by Tosoh Corporation.

Mobile phase solvent: tetrahydrofuran

Flow rate: 1.0 ml / min

Column temperature: 40 DEG C

(Example 1)

The acrylic copolymer (A-1) and the acrylic copolymer (B-1) of the copolymer solution obtained in Synthesis Example 1 were mixed at a weight ratio (in terms of nonvolatile matter) of (A-1) / , 0.5 part of ethylene glycol diglycidyl ether as an epoxy compound and 10 parts of trimethylolpropane adduct of trilene isocyanate as a polyisocyanate compound were mixed. Ethyl acetate was further added to adjust the non-volatile content to 20% .

The pressure-sensitive adhesive was dried on a polyethylene terephthalate-releasable sheet having a thickness of 38 탆 and then coated to a thickness of 25 탆, followed by hot air drying at 100 캜 for 2 minutes to form a pressure-sensitive adhesive layer. Subsequently, a cross section of a laminated polarizing plate in which both surfaces of a polyvinyl alcohol (PVA) polarizer were sandwiched between triacetylcellulose films (hereinafter referred to as "TAC films ") was adhered to this pressure- Film / PVA / TAC film ". Subsequently, the resulting pressure-sensitive adhesive sheet was aged for 1 week at a temperature of 35 DEG C and a relative humidity of 55% to obtain a laminate.

(Examples 2 to 50 and Comparative Examples 1 to 20)

A pressure-sensitive adhesive was obtained in the same manner as in Example 1, according to the blend ratios shown in Tables 3 and 4. Further, a laminate was obtained in the same manner as in Example 1.

[Table 3]

[Table 4]

The obtained laminate was evaluated as follows.

(1) Evaluation of Heat Resistance and Moisture Resistance

The obtained laminate was prepared in a size of 160 mm in width and 120 mm in length. The peelable sheet was then peeled off and adhered to the alkali-free glass using a laminator. The glass plate to which the laminate was adhered was held in a pressure autoclave at 50 DEG C and 5 atm for 20 minutes to adhere the members to each other to obtain a measurement sample. The heat resistance of the measurement sample was evaluated by evaluating the resistance in a high temperature atmosphere. That is, after leaving the sample at 85 ° C for 500 hours, the presence or absence of foaming, peeling, or peeling was visually observed. The resistance of the measurement sample was evaluated by resistance evaluation in a high temperature and high humidity environment. That is, the sample was allowed to stand at 60 ° C and 95% relative humidity for 500 hours, and the presence or absence of foaming, peeling, or peeling was visually observed. The heat resistance and the humid heat resistance were evaluated according to the following criteria.

◎: "No foaming, peeling, peeling is recognized at all, and it is good"

○: "One of 0.5 mm or less foaming, peeling, peeling is recognized, but there is no practical problem"

X: "There is foam, peeling, peeling and can not be used at all."

(2) Light leakage evaluation

Two sheets of the obtained laminate were prepared in a size of 160 mm in width and 120 mm in length. Subsequently, the peelable sheet was peeled off and two laminated bodies were adhered to both sides of the alkali-free glass substrate using a laminator so that the absorption axis of the polarizing plate was orthogonal. Then, the squeezed product was held in a pressure autoclave at 50 DEG C and 5 atm for 20 minutes to closely contact the members to obtain a measurement sample. After the measurement sample was allowed to stand at 85 캜 for 500 hours, light leakage when light was transmitted through the polarizing plate was visually observed. Light leakage was evaluated according to the following criteria.

◎: "There is no white spot, it is good"

○: "There are some white points, but there are no practical problems"

X: "There is a whiteness as a whole and can not be used"

(3) Evaluation of re-peelability

The obtained laminate was prepared in a size of 25 mm in width and 150 mm in length. The peelable sheet was then peeled off and attached to a non-alkali glass using a laminator. And then kept in a pressure autoclave at 50 DEG C and 5 atm for 20 minutes to adhere the members to each other to obtain a measurement sample. The test samples were allowed to stand at 85 占 폚 for 3 hours and then peeled at a rate of 300 mm / min in a direction of 180 占 using a tensile tester in an environment of 23 占 폚 and relative humidity of 50%. Subsequently, discoloration of the glass surface after peeling was visually observed and evaluated according to the following criteria.

○: "Adhesive residue, fogging is not recognized and is good"

X: "Adhesive residue, fogging is recognized and practically impossible"

(4) Evaluation of indentation

The obtained laminate was prepared in a size of 50 mm in width and 50 mm in length. Then, the peelable sheet was placed on the glass plate, and a stainless steel ball having a weight of 500 g was placed at the center of the laminate and allowed to stand for 30 minutes. Immediately after the stainless steel balls were removed, pressing marks (indentations) on the laminate were visually observed. Further, the evaluation was performed by leaving the stainless steel ball for 1 minute. The same pressing trace was observed with the naked eye. And evaluated according to the following criteria. In addition, stress relieving property is particularly excellent when the indentation remains difficult.

◎: "Stainless steel balls are kept for 1 minute, then the marks are completely lost after 24 hours"

○: "After holding the stainless steel ball for 1 minute, the pressed trace is not completely lost after 24 hours, but after 30 seconds, the trace is completely lost after 24 hours"

X: "Stainless steel balls are held for 30 seconds, and marks are not completely lost after 24 hours"

120

(5) Storage elastic modulus (G ')

The obtained pressure-sensitive adhesive was applied to a peelable sheet so as to have a thickness of 30 탆 after drying and dried to form a pressure-sensitive adhesive layer. Several layers of the obtained pressure-sensitive adhesive layer were laminated so as to have a thickness of about 30 mm. After removing the autoclave bubble, a hole was made with a diameter of 8 mm to obtain a cylindrical test piece. The storage elastic modulus (G ') of the test piece was measured by the twist shear method under the following conditions.

Measuring device: Dynamic viscoelasticity measuring device "DYNAMIC ANALYZER RDA III" manufactured by TEI INSTRUMENTS · JAPAN

Frequency: 1Hz

Temperature: 23 ° C, 80 ° C

[Table 5]

[Table 6]

From the results of Table 5 and Table 6, as in Examples 1 to 50, the pressure-sensitive adhesive of the present invention is excellent in durability, stress relaxation property and re-releasability in a high temperature atmosphere and high temperature and high humidity environment. On the other hand, Comparative Examples 1 to 20 could not satisfy all of the above characteristics.

Claims (9)

An acrylic polymer (A) having no hydroxyl group and having a carboxyl group; An acrylic polymer (B) having no hydroxyl group and having no carboxyl group; At least one compound selected from an epoxy compound, a metal chelate compound and an aziridine compound; A pressure-sensitive adhesive comprising a polyisocyanate compound. The method according to claim 1,
Wherein the ratio of the acrylic copolymer (A) to the acrylic copolymer (B) is (A) / (B) = 95/5 to 5/95 by weight. 3. The method according to claim 1 or 2,
Wherein the acrylic copolymer (A) has a weight average molecular weight of 500,000 to 2,000,000 and the acrylic copolymer (B) has a weight average molecular weight of 100,000 to 1,000,000. A pressure-sensitive adhesive sheet comprising a substrate and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive according to any one of claims 1 to 3. 5. The method of claim 4,
Wherein the substrate is an optical member. The method according to claim 4 or 5,
Wherein the pressure-sensitive adhesive layer has a storage elastic modulus (G ') of 0.1 to 5.0 MPa and a storage elastic modulus (G') at 80 DEG C of 0.1 to 2.0 MPa at 23 占 폚. A pressure-sensitive adhesive sheet comprising a polarizing plate and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive according to any one of claims 1 to 3. A glass layer; A pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive according to any one of claims 1 to 3; And an optical member are sequentially laminated. 9. The method of claim 8,
Wherein the optical member is a polarizing plate.