JP2014196376A - Adhesive mass and adhesive sheet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive mass that can make an adhesive sheet in which a removable property is excellent, after being exposed to a high temperature environment and a high temperature high humidity environment, floating and peeling from an adherend hardly generate in for example, a glass and a plastic or the like, a stress relaxation property is favorable, and an impression hardly occurs in an adhesive mass layer.SOLUTION: An adhesive mass includes: an acrylic polymer (A) that has no hydroxy group and has a carboxyl group; an acrylic polymer (B) that has no carboxyl group and has a hydroxy group; one or more compounds selected from an epoxy compound, a metal chelate compound, and an aziridine compound; and a polyisocyanate compound.

Description

  The present invention relates to an adhesive that can be used for members such as plastic and glass.

Display devices such as liquid crystal displays used in various devices such as home and commercial appliances such as electronic calculators, electronic watches, mobile phones, and televisions are becoming larger, especially liquid crystal televisions and plasma televisions. The increase in size is remarkable. In recent years, touch panel type liquid crystal displays such as smartphones and tablets are rapidly spreading, and a large market expansion is expected in the future. On the other hand, liquid crystal displays are also used in in-vehicle devices such as car navigation systems, and are required to have durability that can be used in harsh interior environments such as high-temperature and high-humidity atmospheres.
The liquid crystal display uses polarizing plates and retardation plates having various optical functions, and these are attached to an adherend such as a liquid crystal cell using glass or transparent plastic via an adhesive. Affixed.

  The polarizing plate is a laminate having a configuration in which a polyvinyl alcohol film is generally sandwiched between triacetyl cellulose films and cycloolefin films. These films have different mechanical properties and therefore have different dimensional change rates during heating. Therefore, when placed in a high temperature atmosphere, the laminate often warps.

  Here, for example, when a laminate of polarizing plate / adhesive layer / glass (glass is a surface member of a liquid crystal cell) is left in a high-temperature atmosphere, if warpage resulting from the dimensional change rate between the constituent members of the polarizing plate occurs, Bubbles (foaming) are generated at the bonding interface between the agent layer and the glass, and the problem arises that the polarizing plate is lifted from the glass and peeled off. In addition, the stress distribution of the laminate becomes uneven due to warpage, and as a result of the stress being concentrated on the peripheral edge of the laminate, light leaks from the four corners and the peripheral edge of the laminate, so-called “light leakage phenomenon”. There was a problem. The above problem also occurs in a high temperature and high humidity atmosphere.

  On the other hand, when a polarizing plate is bonded to an optical component such as a liquid crystal cell in a manufacturing process such as a liquid crystal display, the polarizing plate is peeled off after a certain amount of time has elapsed since the bonding position has shifted. Reuse of expensive liquid crystal cells has been carried out. Therefore, the pressure-sensitive adhesive is required to have a function (reworkability) capable of re-peeling the polarizing plate from the liquid crystal cell after a lapse of time since sticking.

  In order to solve these problems, in Patent Document 1, in order to solve the problem of light leakage, by adding a plasticizer or the like to the pressure-sensitive adhesive, a technique for softening the pressure-sensitive adhesive layer and imparting stress relaxation properties. Is disclosed.

  Patent Document 2 discloses a technique for improving the stress relaxation property of a coating film and preventing light leakage by including an acrylic copolymer using an aromatic ring-containing monomer in order to impart stress relaxation property. ing.

  On the other hand, in Patent Document 3, in order to impart removability, a high molecular weight acrylic polymer having a weight average molecular weight of 500,000 or more has a high acid value and a low molecular weight having a weight average molecular weight of 0.2 to 100,000. Techniques for blending acrylic polymers are disclosed.

  Furthermore, in patent document 4, the technique which improves stress relaxation property by using together the acrylic polymer with a weight average molecular weight of 700,000 or more which has a carboxyl group, and the acrylic polymer with a weight average molecular weight of 800-50,000. Is disclosed.

  Moreover, in patent document 5, sufficient cohesion force is obtained by using together the acrylic polymer which has a hydroxyl group, and the acrylic polymer containing the monomer containing (meth) acrylic acid ester whose Tg is 60 degreeC or more. A technique for obtaining the above is disclosed.

Japanese Patent Laid-Open No. 9-87593 JP 2007-169329 A JP 2010-1000071 A Japanese Patent No. 4136524 Japanese Patent No. 4788937

  However, conventional pressure-sensitive adhesives, when added with a plasticizer, cause bleed-out that contaminates the adherend when the polarizing plate is peeled off, and reduce cohesive force, resulting in floating and peeling over time. It becomes easy. Moreover, there was a problem that the coating film was whitened by adding an excessive amount of plasticizer.

  In addition, the pressure-sensitive adhesive using the aromatic ring-containing monomer has a problem that white spots are generated and optical properties are inferior in light leakage evaluation.

  Moreover, the adhesive which uses the copolymer from which a weight average molecular weight differs using a peroxide was not practical, since the drying conditions of an adhesive were restrict | limited.

  Moreover, 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 remarkably lowered by the low molecular weight copolymer.

  In addition, the pressure-sensitive adhesive in which a high-Tg copolymer is blended with a general copolymer has good cohesive strength, but has a problem that white spots occur due to insufficient stress relaxation properties. .

  The present invention, when used for an adhesive film, has excellent releasability, and is less likely to float or peel off from the adherend even after being exposed to a high temperature environment or a high temperature and high humidity environment. It aims at providing the adhesive which can create not only the impression layer at the time of adhesive film production but also the adhesive layer which can be produced.

The present invention relates to an acrylic polymer (A) having no hydroxyl group and having a carboxyl group, an acrylic polymer (B) having no carboxyl group and having a hydroxyl group, an epoxy compound, a metal chelate compound, and an aziridine compound It is the adhesive containing at least 1 compound chosen from these, and a polyisocyanate compound.
About.

  According to the present invention configured as described above, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive is composed of at least one compound selected from the carboxyl group of the acrylic polymer (A), the epoxy compound, the metal chelate compound, and the aziridine compound. By crosslinking reaction, two polymer networks in which the acrylic polymer (B) is crosslinked with the polyisocyanate compound are formed. Since the pressure-sensitive adhesive layer does not impair the cohesive force and is excellent in stress relaxation, when left in a high-temperature atmosphere or high-temperature and high-humidity atmosphere, it does not easily float or peel off, and does not easily leak light. It has the effect that it does not easily occur.

  According to the present invention, it is excellent in removability, and after being exposed to a high temperature environment or a high temperature and high humidity environment, for example, glass and plastics are unlikely to float or peel off from the adherend, and light leakage does not easily occur. It was possible to provide a pressure-sensitive adhesive capable of producing a pressure-sensitive adhesive sheet that hardly causes indentation.

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

  In the present invention, the acrylic polymer (A) and the acrylic polymer (B) are copolymers of monomers containing a (meth) acrylic acid ester. The acrylic polymer (A) and the acrylic polymer (B) each form a polymer network by a cross-linking reaction, thereby obtaining an effect of suppressing floating, peeling, light leakage, and indentation. In the present invention, (meth) acrylic acid ester includes acrylic acid ester and methacrylic acid ester.

In this invention, an acrylic polymer (A) is a polymer which does not have a hydroxyl group but has a carboxyl group. Specifically, it is necessary to copolymerize a monomer mixture containing a monomer having a carboxyl group and not a monomer having a hydroxyl group as a reactive functional group.
Monomers containing a carboxyl group include, for example, (meth) acrylic acid, monohydroxyethyl acrylate ester of phthalate, p-carboxybenzyl acrylate ester, ethylene oxide modified (added mole number: 2 to 18) phthalate acrylic acid Ester, monohydroxypropyl acrylate ester, monohydroxyethyl acrylate succinate, β-carboxyethyl acrylate, 2- (4-benzoyl-3-hydroxyphenoxy) ethyl acrylate, maleic acid, monoethylmaleic acid , Itaconic acid, citraconic acid, fumaric acid and the like. These can 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 and more preferably 0.5 to 15% by weight in 100% by weight of the monomer mixture. When the content is 0.01% or more, the cohesive force is further improved. Moreover, it becomes easy to make cohesion force and stress relaxation property compatible because content will be 20 weight% or less.

  The acrylic polymer (B) of the present invention is a polymer having no carboxyl group and having a hydroxyl group. Specifically, it is necessary to copolymerize a monomer mixture that does not include a monomer having a carboxyl group as a reactive functional group but includes 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, and 2-hydroxybutyl (meth) acrylate. (Meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate And glycol mono (meth) acrylic acid esters such as polyethylene glycol mono (meth) acrylic acid ester, polypropylene glycol mono (meth) acrylic acid ester, 1,4-cyclohexanedimethanol mono (meth) acrylic acid ester, caprolactone modified ( Meta) Acu Le esters, such as hydroxyethyl acrylamide. Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable. These can 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 and more preferably 0.2 to 15% by weight in 100% by weight of the monomer mixture. When the content is 0.01% or more, the cohesive force is further improved. Moreover, it becomes easy to make cohesion force and stress relaxation property compatible because content will be 20 weight or less.

Monomers that can be used 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, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth) Hexyl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, tetradecyl (meth) acrylate, (meth ) Hexadecyl acrylate, octadecyl (meth) acrylate, and the like. Among these, butyl (meth) acrylate is preferable from the viewpoint that good adhesive performance is easily obtained. These can be used alone or in combination of two or more.

  The (meth) acrylic acid alkyl ester is preferably contained in an amount of 5 to 50% by weight, more preferably 10 to 30% by weight, based on 100% by weight of the monomer mixture. When the content is 5% or more, the cohesive force is further improved. Moreover, it becomes easy to make cohesion force and stress relaxation property compatible because content will be 50 weight or less.

  The other vinyl monomers include an amide bond-containing monomer, an epoxy group-containing monomer, an amino group-containing monomer, a monomer having an alkylene oxide unit, vinyl acetate, and crotonic acid. Vinyl, styrene, acrylonitrile and the like are preferable, but are not particularly limited as long as they can be copolymerized.

  Examples of the monomer containing an amide bond include (meth) acrylamide, N-methylacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-dimethylaminopropyl (meta). ) Heterocycles such as (meth) acrylamide compounds such as acrylamide, diacetone acrylamide, N- (hydroxymethyl) acrylamide, N- (butoxymethyl) acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, etc. , N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide and the like.

  Examples of the monomer containing an epoxy group include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 6-methyl (meth) acrylate. Examples include 3,4-epoxycyclohexylmethyl.

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

  The monomer having an alkylene oxide unit preferably has units such as ethylene oxide and propylene oxide. Specifically, for example, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-phenoxyethyl acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, methoxypolypropylene Examples include glycol (meth) acrylic acid ester, ethoxy polypropylene glycol (meth) acrylic acid ester, phenoxypolyethylene glycol (meth) acrylic acid ester, and phenoxypolypropylene glycol (meth) acrylic acid ester.

  Other vinyl monomers can be used alone or in combination of two or more.

  The other vinyl monomer is preferably contained in an amount of 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, the cohesive force is further improved. Moreover, it becomes easy to make cohesion force and stress relaxation property compatible because content will be 30 weight or less.

  The pressure-sensitive adhesive of the present invention preferably contains the acrylic polymer (A) and the acrylic polymer (B) in a weight ratio of (A) / (B) = 95/5 to 5/95, A) / (B) = 90/10 to 10/90 is more preferable, and (A) / (B) = 90/10 to 50/50 is more preferable. By containing 90% by weight or less of the acrylic polymer (A) in the total amount of (A) and (B), the cohesive force is further improved. Moreover, stress relaxation property improves more by containing 90 weight% or less of acrylic polymers (B). In the present invention, the mixing ratio of the acrylic polymer (A) and the acrylic polymer (B) is important, and the acrylic polymer (A) and the acrylic polymer (B) are (A) / (B) Mixing to a weight ratio of 95/5 to 5/95 makes it possible to suppress light leakage and to suppress the floating and peeling of the polarizing plate.

In the pressure-sensitive adhesive of the present invention, the weight average molecular weight of the acrylic polymer (A) is preferably 500,000 to 2,000,000. Since cohesion force etc. improve more because it exists in the range of 500,000-2 million, a float and peeling can be suppressed more and stress relaxation property improves more.
The weight average molecular weight of the acrylic polymer (B) is preferably 100,000 to 1,000,000. Since cohesive force etc. improve more by being in the range of 100,000-1 million, a float and peeling can be suppressed more and stress relaxation property improves more.
Further, when the acrylic polymers (A) and (B) are mixed, the molecular weight distribution (molecular weight distribution (Mw / Mn) representing the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn)) is 2 to 2. 20 is preferred. By being in the said range, it is hard to produce a float and peeling and adhesive force improves and improves. In addition, the said weight average molecular weight and number average molecular weight are the values of polystyrene conversion measured by the gel permeation chromatography (GPC) method. Details of the GPC measurement method are described in the Examples.

  In the present invention, the acrylic polymer (A) and the acrylic polymer (B) can be obtained by radical polymerization of the monomer mixture with a radical polymerization initiator. The radical polymerization may be a known polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, etc. In the present invention, solution polymerization is preferred. Solvents that can be used in solution polymerization are preferably acetone, methyl acetate, ethyl acetate, toluene, xylene, anisole, methyl ethyl ketone, cyclohexanone, and the like. The polymerization temperature is preferably a boiling point reaction of 60 to 120 ° C., 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 radicals at the polymerization temperature, and known compounds such as peroxides and azo compounds can be used.
Examples of the peroxide include di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, 2,5- Dialkyl peroxides such as di (t-butylperoxy) hexyne-3;
peroxyesters such as t-butylperoxybenzoate, t-butylperoxyacetate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane;
Ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide;
2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t- Peroxyketals such as butylperoxy) cyclohexane and n-butyl-4,4-bis (t-butylperoxy) valate;
Hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylcyclohexane-2,5-dihydroperoxide;
Diacyl peroxides such as benzoyl peroxide, decanoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide;
Examples thereof include organic peroxides such as peroxydicarbonates such as bis (t-butylcyclohexyl) peroxydicarbonate, and mixtures thereof.

Examples of the azo compounds include 2,2′-azobisbutyronitriles such as 2,2′-azobisisobutyronitrile (abbreviation: AIBN) and 2,2′-azobis (2-methylbutyronitrile). ;
2,2′-azobisvaleronitriles such as 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile);
2,2′-azobispropionitriles such as 2,2′-azobis (2-hydroxymethylpropionitrile);
1,1′-azobis-1-alkanenitriles such as 1,1′-azobis (cyclohexane-1-carbonitrile) can be used.
The radical polymerization initiators can 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.

The pressure-sensitive adhesive of the present invention uses a curing agent that reacts with the reactive functional group of the acrylic polymer (A), and a curing agent that reacts with the reactive functional group of the acrylic polymer (B). It is preferable to use it. The cross-linking network of the acrylic polymer (A) and the cross-linking network of the acrylic polymer (B) each have an intertwined part, a part that exists independently, and a part that interpenetrates. Force and good stress relaxation are obtained.
Here, the curing agent that 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, an N-methylol group-containing compound, or the like. . The curing agent that reacts with the acrylic polymer (B) having a hydroxyl group is preferably a polyisocyanate compound. The curing agent for the acrylic polymer (A) is preferably an epoxy compound, a metal chelate compound, or an aziridine compound because the cohesive force and stress relaxation properties are further improved.

  Examples of the epoxy compound include bisphenol A-epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol diglycidyl ether. , Trimethylolpropane triglycidyl ether, diglycidyl aniline, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane, N , N, N ′, N′-tetraglycidylaminophenylmethane and the like.

  Examples of the metal chelate compounds include coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium, and acetylacetone or ethyl acetoacetate. It is done. Specific examples include aluminum ethyl acetoacetate / diisopropylate, aluminum trisacetylacetonate, aluminum bisethylacetoacetate / monoacetylacetonate, and aluminum alkylacetoacetate / diisopropylate.

  Examples of the aziridine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxite), N, N′-toluene-2,4-bis (1-aziridinecarboxite), and bisisophthalo. Yl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxite), 2,2′-bishydroxymethyl Butanol-tris [3- (1-aziridinyl) propionate], trimethylolpropane tri-β-aziridinylpropionate, tetramethylolmethanetri-β-aziridinylpropionate, tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, 4,4′-bis (ethyleneiminocarbonylamino) diph Nirumetan, and the like.

  Examples of the carbodiimide compound include a high molecular weight polycarbodiimide produced by decarboxylation condensation reaction of a diisocyanate compound in the presence of a carbodiimidization catalyst. Examples of such high molecular weight polycarbodiimides include Nisshinbo's Carbodilite series. Among these, Carbodilite V-01, 03, 05, 07, and 09 are preferable because of 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, but includes tetracarboxylic dianhydride, hexacarboxylic dianhydride, hexacarboxylic dianhydride. And a maleic anhydride copolymer resin. In addition, polycarboxylic acid, polycarboxylic acid ester, polycarboxylic acid half ester, and the like that can be converted into an anhydride via a dehydration reaction during the reaction are included in the “acid anhydride group-containing compound” of the present invention.

  Examples of the tetracarboxylic dianhydride include pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, oxydiphthalic dianhydride, diphenylsulfonetetracarboxylic dianhydride, diphenylsulfidetetracarboxylic Examples thereof include acid dianhydride, butanetetracarboxylic dianhydride, perylenetetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride and the like.

  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 araliphatic polyisocyanate, an alicyclic polyisocyanate, and the like. A burette body, a nurate body, and an adduct body are preferred.

  Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6 -Tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', Examples thereof include 4 "-triphenylmethane triisocyanate.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HMDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, and 1,3-butylene diisocyanate. , Dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and the like.

  Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene. 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

  Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (also known as IPDI, isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1, Examples include 4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanate methyl) cyclohexane, and the like. .

  The burette body refers to a self-condensate having a burette bond in which the isocyanate monomer is self-condensed. Specific examples include a burette of hexamethylene diisocyanate.

  The nurate body refers to a trimer of the isocyanate monomer, and examples thereof include a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate, and a trimer of tolylene diisocyanate.

  The adduct body is a bifunctional or higher functional isocyanate compound obtained by reacting the isocyanate monomer with a bifunctional or higher molecular weight active hydrogen-containing compound. For example, a compound obtained by reacting trimethylolpropane and hexamethylene diisocyanate (trimethylolpropane). A compound obtained by reacting trimethylol propane with xylylene diisocyanate, a compound obtained by reacting trimethylol propane with xylylene diisocyanate, a compound obtained by reacting trimethylol propane with isophorone diisocyanate, 1,6-hexanediol and hexamethylene diisocyanate. Examples thereof include reacted compounds.

Examples of the bifunctional or higher functional low molecular active hydrogen-containing compound include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, and 3,3′-dimethylol. Heptane, 2-methyl-1,8-octanediol, 3,3′-dimethylolheptane, 2-butyl-2-ethyl-1,3-propanediol, polyoxyethylene glycol (additional number of moles of ethylene oxide of 10 or less ), Polyoxypropylene glycol (additional mole number of propylene oxide of 10 or less), 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonane Diol, neopentyl glycol, butyl ethyl penta Diol, 2-ethyl-1,3-hexanediol, cyclohexanediol, cyclohexanedimethanol, tricyclodecanedimethanol, cyclopentadiene engine methanol, aliphatic or alicyclic diols and dimer diol;
1,3-bis (2-hydroxyethoxy) benzene, 1,2-bis (2-hydroxyethoxy) benzene, 1,4-bis (2-hydroxyethoxy) benzene, 4,4′-methylenediphenol, 4, 4 ′-(2-norbornylidene) diphenol, 4,4′-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene, 4,4′-isopropylidenephenol, or bisphenols such as bisphenol A and bisphenol F Aromatic diols such as bisphenols obtained by adding alkylene oxide such as ethylene oxide and propylene oxide to
1,1,1-trimethylolpropane, 1,1,1-trimethylolbutane, 1,1,1-trimethylolpentane, 1,1,1-trimethylolhexane, 1,1,1-trimethylolheptane, 1,1,1-trimethyloloctane, 1,1,1-trimethylol nonane, 1,1,1-trimethyloldecane, 1,1,1-trimethylolundecane, 1,1,1-trimethyloldodecane, 1,1,1-trimethylol tridecane, 1,1,1-trimethylol tetradecane, 1,1,1-trimethylol pentadecane, 1,1,1-trimethylol hexadecane, 1,1,1-trimethylol hepta Decane, 1,1,1-trimethylol octadecane, 1,1,1-trimethylol nanodecane, 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, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol-2-ethyl-hexane, , 1,1-trimethylol-3-ethyl-hexane, trimethylol branched alkanes such as 1,1,1-trimethylolisoheptadecane, trimethylolbutene, trimethylolheptene, trimethylolpentene, trimethylolhexene, Trimethylol heptene, trimethylol octene, trimethylol decene, trimethylol dode , Trimethylol tridecene, trimethylol pentadecene, trimethylol hexadecene, trimetroleheptadecene, trimethylol octadecene, 1,2,6-butanetriol, 1,2,4-butanetriol, glycerin, etc. Kind;
Tetrafunctional or higher functional polyols such as pentaerythritol, dipentaerythritol, sorbitol, xylitol;
Ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, heptylenediamine, octylenediamine, nonylenediamine, diaminodicyclohexylmethane, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1, Aliphatic polyamines such as 3-bis (aminomethyl) cyclohexane, triethylenetetramine, diethylenetriamine, triaminopropane;
Aromatic polyamines such as phenylenediamine, tolylenediamine, diaminodiphenylmethane, diaminodiphenyl ether;
Ethylenedithiol, propylenedithiol, butylenedithiol, pentylenedithiol, hexylenedithiol, heptylenedithiol, octylenedithiol, nonylenedithiol, dimercaptodicyclohexylmethane, 3-mercaptomethyl-3,5,5-trimethylcyclohexylthiol, Examples include polythiols such as 1,3-bis (mercaptomethyl) cyclohexane, 1,4-bis (3-mercaptobutyryloxy) butane, and pentaerythritol tetrakis (3-mercaptobutyrate).
These polyfunctional low molecular active hydrogen-containing compounds can be used alone or in combination of two or more.

  From the viewpoint of forming a sufficient cross-linked structure, the polyisocyanate compound is preferably a trifunctional isocyanate compound, and more preferably an adduct that is a reaction product of an isocyanate monomer and a trifunctional low molecular active hydrogen-containing compound. Specifically, a trimethylolpropane adduct of hexamethylene diisocyanate, a trimethylolpropane adduct of tolylene diisocyanate, a trimethylolpropane adduct of isophorone diisocyanate, a nurate of isophorone diisocyanate, and a trimethylolpropane adduct of xylylene diisocyanate are preferred. Further, an adduct body of tolylene diisocyanate trimethylolpropane and a nurate body of isophorone diisocyanate are preferable. These polyisocyanate compounds can be used alone or in combination of two or more.

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

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

  The pressure-sensitive adhesive of the present invention preferably contains a silane coupling agent. Since the adhesive force is further improved by using the silane coupling agent, the floating and peeling can be further suppressed.

Examples of the silane coupling agent include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyltripropoxysilane, and 3- (meth). An alkoxysilane compound having a (meth) acryloxy group such as acryloxypropyltributoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane;
Alkoxysilane compounds having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane;
3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltripropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl)- 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) Alkoxysilane compounds having an amino group, such as -3-aminopropylmethyldiethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane;
Alkoxysilane compounds having a mercapto group such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane;
3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Alkoxysilane compounds having an epoxy group such as 3-glycidoxypropylmethyldiethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane;
Tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane;
3-chloropropyltrimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, styryltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyl Examples thereof include triethoxysilane, hexamethyldisilazane, and a silicone resin having an alkoxysilyl group in the molecule.

  The silane coupling agent is preferably used in an amount of 0.01 to 2 parts by weight with respect to a total of 100 parts by weight of the acrylic copolymer (A) and the acrylic copolymer (A). A range of ˜1 part by weight is more preferred.

  In the pressure-sensitive adhesive of the present invention, as long as the effects of the present invention are not impaired, tackifying resins, various resins, oils, softeners, dyes, pigments, antioxidants, ultraviolet absorbers, weathering stabilizers are optional components. Plasticizers, fillers, antiaging agents, antistatic agents, and the like may be blended.

  The pressure-sensitive adhesive of the present invention is suitable as a pressure-sensitive adhesive for optical members, as well as various plastic sheets, general labels and seals, paints, elastic wall materials, waterproof coating materials, flooring materials, tackifiers, pressure-sensitive adhesives, and laminates. Structural adhesives, sealing agents, molding materials, surface modification coating agents, binders (magnetic recording media, ink binders, casting binders, fired brick binders, graft materials, microcapsules, glass fiber sizing, etc.), urethane foam ( (Hard, semi-rigid, soft), urethane RIM, UV / EB curable resin, high solid paint, thermosetting elastomer, microcellular, textile processing agent, plasticizer, sound absorbing material, vibration damping material, surfactant, gel coat agent, Resin for artificial marble, impact modifier for artificial marble, resin for ink, film (laminate adhesive, protective film) Beam, etc.), laminated glass resin, reactive diluent, various molding materials, elastic fiber, artificial leather, as a raw material for synthetic leather, can also very effectively used as various resin additives and a raw material thereof or the like.

  The pressure-sensitive adhesive sheet of the present invention includes a base material and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive of the present invention. The pressure-sensitive adhesive sheet can be obtained, for example, by forming a pressure-sensitive adhesive layer by applying a pressure-sensitive adhesive to a substrate and drying it. Moreover, an adhesive is applied to the peelable sheet and dried to form an adhesive layer, and the substrate is bonded. In addition, the adhesive layer should just be provided in the at least one surface of the base material. In the present invention, a sheet, a film and a tape are synonymous. Needless to say, the peelable sheet is bonded to the surface of the pressure-sensitive adhesive layer that is not in contact with the base material.

  When applying the adhesive, a suitable liquid medium, for example, a hydrocarbon solvent such as toluene, xylene, hexane, heptane; an ester solvent such as ethyl acetate or butyl acetate; a ketone solvent such as acetone or methyl ethyl ketone; The viscosity can be adjusted by adding halogenated hydrocarbon solvents such as dichloromethane and chloroform; ether solvents such as diethyl ether, methoxytoluene and dioxane, and other hydrocarbon solvents. The pressure-sensitive adhesive can be heated to reduce the viscosity. However, since water, alcohol, etc. inhibit the crosslinking reaction of an acrylic copolymer (B) and a polyisocyanate compound, it is preferable to avoid use.

  Examples of the substrate include cellophane, plastic, rubber, foam, cloth, rubber cloth, resin-impregnated cloth, glass plate, and wood. The substrate may be plate-shaped or film-shaped. Moreover, the structure which laminated | stacked the base material independently or several base materials is also preferable.

  Examples of the plastic include polyolefin resins such as polyvinyl alcohol, triacetyl cellulose, polypropylene, polyethylene, polycycloolefin, and ethylene-vinyl acetate copolymer, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Polycarbonate resin, polynorbornene resin, polyarylate resin (PAR: copolymer resin of bisphenol A and phthalic acid), polyacrylic resin, polyphenylene sulfide resin, polystyrene resin, polyamide resin, polyimide resin, epoxy resin Examples thereof include resins (resins obtained by reacting epoxy group-containing resins with polyamines or carboxylic anhydrides).

  In the present invention, the pressure-sensitive adhesive can be applied by a known method. For example, Mayer bar, applicator, brush, spray, roller, gravure coater, die coater, lip coater, comma coater, knife coater, reverse coater, spin coater and the like can be mentioned. There is no restriction | limiting in particular in a drying method, The thing using hot air drying, infrared rays, and the pressure reduction method is mentioned. The drying condition may be hot air heating of about 60 to 160 ° C.

  0.1-300 micrometers is preferable and, as for the thickness of an adhesive layer, 1-100 micrometers is more preferable. When the thickness is less than 0.1 μm, sufficient adhesive strength may not be obtained, and even when the thickness exceeds 300 μm, the performance such as adhesive strength is often not improved.

  Furthermore, 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 1 day at 23 ° C. after being bonded to an alkali-free glass. When the adhesive strength is 2 N / 25 mm or more, it becomes easy to obtain sufficient adhesive strength that is unlikely to cause floating and peeling. In addition, when the adhesive strength is 20 N / 25 mm or less, peeling from the adherend becomes easier.

It is preferable that the storage elastic modulus (G ') at 23 degreeC of the adhesive layer of the adhesive sheet of this invention is 0.1-5 Mpa. When the storage elastic modulus (G ′) at 23 ° C. is 0.1 MPa or more, the adhesive physical properties are further improved. Moreover, adhesive force improves more because the storage elastic modulus (G ') in 23 degreeC becomes 5 Mpa or less. The storage elastic modulus (G ′) at 23 ° C. is more preferably 0.1 to 2.0 MPa.
The storage elastic modulus (G ′) at 80 ° C. of the pressure-sensitive adhesive layer is preferably 0.1 to 2 MPa. When the storage elastic modulus (G ′) at 80 ° C. is 0.1 MPa or more, floating and peeling in a high temperature atmosphere and a high temperature and high humidity atmosphere can be further suppressed. Moreover, the adhesive force in a high temperature atmosphere and a high temperature / humidity atmosphere can be improved more because the storage elastic modulus (G ') in 80 degreeC will be 2 Mpa or less. The storage elastic modulus (G ′) at 80 ° C. is more preferably 0.1 to 1 MPa. Details of the method for measuring storage elastic modulus (G ′) are described in Examples.

  When an adhesive is applied to a substrate to produce an adhesive sheet, the applied adhesive sheet is generally wound once and then subjected to processing such as cutting. In some cases, foreign matters such as dust or dust mixed from the outside during the processing adhere to the adhesive sheet, and the foreign matter may leave a trace such as a press mark (referred to as an indentation in the present invention) on the adhesive layer. In particular, when a polarizing plate is used for the base material, after the pressure-sensitive adhesive sheet is cut into a desired size, a polishing step is performed to smooth the end portion. In the process, since indentation is likely to occur, the yield is remarkably reduced. Since the pressure-sensitive adhesive of the present invention has a storage elastic modulus (G ′) at 23 ° C. of 0.1 to 5 MPa of the pressure-sensitive adhesive layer, it is possible to further suppress the occurrence of indentation during the production of the pressure-sensitive adhesive sheet. Indentation can be further suppressed when the storage elastic modulus (G ′) is 0.1 MPa or more. Moreover, adhesive force can be improved more by becoming 5 Mpa or less.

  The pressure-sensitive adhesive sheet of the present invention can be suitably used for laminating optical members. That is, it is preferable to use an optical member for the 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 as a base material is attached to a glass member of a liquid crystal cell and used as a liquid crystal cell member. When the optical member is a polarizing plate, even when left in a high-temperature atmosphere and a high-temperature and high-humidity atmosphere, the pressure-sensitive adhesive layer has good stress relaxation properties, so that light leakage due to warping of the polarizing plate can be suppressed.

  The pressure-sensitive adhesive sheet of the present invention can be preferably used for various electronics-related members such as liquid crystal displays, plasma displays, touch panels, and electrode peripheral members, protective films, building materials, glass members such as vehicle window glass, polyolefin, ABS, acrylic, etc. It can also be used for metals such as plastic, cardboard, wood, plywood, stainless steel and aluminum.

  EXAMPLES Next, although an Example of this invention is shown and it demonstrates still in detail, this invention is not limited by these. In the examples, “part” means “part by weight”, and “%” means “% by weight”.

<Synthesis Example 1: Acrylic Copolymer (A)>
In a reaction vessel (hereinafter simply referred to as “reaction vessel”) equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 99.5 parts of butyl acrylate, 0.5 part of acrylic acid, 100 parts of ethyl acetate and 0.025 part of 2,2′-azobisisobutyronitrile (hereinafter referred to as AIBN) were charged, and the air in the reaction vessel was replaced with nitrogen gas. Then, it heated to 80 degreeC, stirring under nitrogen atmosphere, and reaction was started. Thereafter, the reaction solution was reacted at reflux temperature for 7 hours. After completion of the reaction, the reaction mixture was cooled, diluted with ethyl acetate and measured for a nonvolatile content of 30% and a viscosity of 3000 m (Mw). The weight average molecular weight was 1,000,000. Let the obtained copolymer be a copolymer (A-1).

<Synthesis Examples 2-20>
Various raw materials were charged according to the weight ratios in Table 1, and an acrylic copolymer (A) was synthesized in the same manner as in Synthesis Example 1. The weight average molecular weight of the obtained acrylic copolymer is shown in Table 1.

<Synthesis Example 21: Acrylic copolymer (B)>
The reaction vessel was charged with 99.8 parts of butyl acrylate, 0.2 part of 2-hydroxyethyl acrylate, 100 parts of ethyl acetate, and 0.025 part of AIBN, and the air in the reaction container was replaced with nitrogen gas. Then, it heated to 80 degreeC, stirring under nitrogen atmosphere, and reaction was started. Thereafter, the reaction solution was reacted at reflux temperature for 7 hours. After completion of the reaction, the 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. Moreover, when the weight average molecular weight (Mw) of the acrylic copolymer was measured using GPC, the weight average molecular weight was 1,000,000. Let the obtained copolymer be a copolymer (B-1).

<Synthesis Examples 22-40>
Various raw materials were charged according to the weight ratios in Table 2, and an acrylic copolymer (B) was synthesized in the same manner as in Synthesis Example 21. The weight average molecular weight of the obtained acrylic copolymer is shown in Table 2.

<Measurement of weight average molecular weight (Mw)>
The weight average molecular weight (Mw) was measured using GPC “LC-GPC system” manufactured by Shimadzu Corporation. GPC is liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified by the difference in molecular size, and the weight average molecular weight (Mw) is determined in terms of polystyrene.
Device name: LC-GPC system “Prominence” manufactured by Shimadzu Corporation
Column: Tosoh Co., Ltd. 4 GMHXL and Tosoh Co., Ltd. HXL-H 1 were connected.
Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 ml / min
Column temperature: 40 ° C

Example 1
The acrylic copolymer (A-1) and the acrylic copolymer (B-1) in the copolymer solution obtained in Synthesis Example 1 are (A-1) / (B-1) = 80 / 20 parts by weight (in terms of non-volatile content), 0.5 parts of ethylene glycol diglycidyl ether as an epoxy compound, 10 parts of trimethylolpropane adduct of tolylene diisocyanate as a polyisocyanate compound, and further ethyl acetate In addition, the non-volatile content was adjusted to 20% to obtain an adhesive.

  The pressure-sensitive adhesive was applied to a polyethylene terephthalate peelable sheet having a thickness of 38 μm so that the thickness after drying was 25 μm, and dried with hot air at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer. Next, one surface of a polarizing plate having a laminated structure in which both sides of a polyvinyl alcohol (PVA) polarizer are sandwiched between triacetyl cellulose films (hereinafter referred to as “TAC film”) is bonded to the pressure-sensitive adhesive layer. An adhesive sheet having a configuration of “/ adhesive layer / TAC film / PVA / TAC film” was obtained. Next, the obtained pressure-sensitive adhesive sheet was aged at a temperature of 35 ° C. and a relative humidity of 55% for 1 week to obtain a laminate.

(Examples 2-50, Comparative Examples 1-20)
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 according to the blending ratios in Table 3 and Table 4. Further, a laminate was obtained in the same manner as in Example 1.

  The obtained laminate was evaluated by the following methods.

(1) Evaluation of heat resistance and wet heat resistance The obtained laminate was prepared to have a width of 160 mm and a length of 120 mm. Next, the peelable sheet was peeled off and attached to an alkali-free glass plate using a laminator. Then, the measurement sample was obtained by hold | maintaining the said glass plate on which this laminated body was affixed for 20 minutes in the autoclave of conditions of 50 degreeC and 5 atmospheres, and closely_contact | adhering each member. The measurement sample was evaluated for heat resistance as resistance evaluation in a high temperature atmosphere. That is, the measurement sample was allowed to stand at 85 ° C. for 500 hours and then visually observed for foaming, floating and peeling. In addition, the heat resistance of the measurement sample was evaluated as an evaluation of resistance in a high-temperature and high-humidity atmosphere. That is, the measurement sample was allowed to stand at 60 ° C. and a relative humidity of 95% for 500 hours and then visually observed for foaming, floating and peeling. Heat resistance and moist heat resistance were evaluated based on the following criteria.
A: “Foaming, floating and peeling are not recognized at all, and it is good”
○: “Bubbling, floating or peeling of 0.5 mm or less is recognized, but there is no practical problem”
X: “There is foaming, floating and peeling all over and cannot be used”

(2) Light Leakage Evaluation Two sheets of the obtained laminate were prepared with a width of 160 mm and a length of 120 mm. Next, the peelable sheet was peeled off, and two laminates were attached to both surfaces of the alkali-free glass plate using a laminator so that the absorption axes of the polarizing plates were orthogonal to each other. Subsequently, the pressure-bonded product was held in an autoclave at 50 ° C. and 5 atm for 20 minutes, and each member was brought into close contact with each other to obtain a measurement sample. The measurement sample was allowed to stand at 85 ° C. for 500 hours, and then light leakage when light was transmitted through the polarizing plate was visually observed. The light leakage was evaluated based on the following criteria.
A: “No white spots and good”
○: “There is a slight white spot, but there is no practical problem”
×: “There are white spots on the entire surface and cannot be used”

(3) Re-peelability evaluation The obtained laminate was prepared in a width of 25 mm and a length of 150 mm. Next, the peelable sheet was peeled off and attached to a non-alkali glass plate using a laminator. Then, the measurement sample was obtained by hold | maintaining for 20 minutes in the autoclave of 50 degreeC and 5 atmospheres conditions, and making each member contact | adhere. After the measurement sample was left at 85 ° C. for 3 hours, a peeling test was performed in which the sample was pulled at a speed of 300 mm / min in the 180 ° direction using a tensile tester in an environment of 23 ° C. and 50% relative humidity. . Subsequently, the cloudiness of the glass surface after peeling was observed visually and evaluated based on the following criteria.
○: “Adhesive residue and cloudiness are not recognized and good”
×: “Adhesive residue, cloudiness is recognized and impractical”

(4) Indentation evaluation The obtained laminate was prepared to have a width of 50 mm and a length of 50 mm. Next, the peelable sheet was placed on the glass plate, and a stainless steel ball having a weight of 500 g was left at the center of the laminate, and left for 30 minutes. The stainless spheres were immediately removed, and the imprint (indentation) attached to the laminate was visually observed. In addition, the stainless steel ball was evaluated by allowing it to stand for 1 minute, and the press marks were visually observed in the same manner as described above. Evaluation was based on the following criteria. In addition, it can be said that it is especially excellent in stress relaxation that an indentation does not remain easily.
A: “The trace after holding the stainless steel ball for 1 minute completely disappears after 24 hours”
○: “A trace after holding a stainless steel ball for 1 minute does not completely disappear after 24 hours, but a trace after holding for 30 seconds completely disappears after 24 hours”
X: “The trace after holding the stainless steel ball for 30 seconds does not completely disappear after 24 hours”

120
(5) Storage elastic modulus (G ′)
The obtained pressure-sensitive adhesive was coated on a peelable sheet so that the thickness after drying was 30 μm, and dried to form a pressure-sensitive adhesive layer. After laminating a plurality of the obtained pressure-sensitive adhesive layers so as to have a thickness of about 30 mm, air bubbles were removed by an autoclave, and then punched out to a diameter of 8 mm to obtain a cylindrical test piece. The storage elastic modulus (G ′) of the test piece was measured by the torsional shear method under the following conditions.
Measuring device: Dynamic viscoelasticity measuring device “DYNAMIC ANALYZER RDA III” manufactured by TA Instruments Japan
Frequency: 1Hz
Temperature: 23 ° C, 80 ° C

From the results of Tables 5 and 6, as shown in Examples 1 to 50, the pressure-sensitive adhesive of the present invention is excellent in durability in high temperature atmosphere and high temperature and high humidity atmosphere, stress relaxation property, and removability. On the other hand, Comparative Examples 1-20 were not able to satisfy | fill all the said characteristics.

Claims (9)

  At least selected from an acrylic polymer (A) having no carboxyl group and having a carboxyl group, an acrylic polymer (B) having no carboxyl group and having a hydroxyl group, an epoxy compound, a metal chelate compound, and an aziridine compound An adhesive comprising one compound and a polyisocyanate compound.   The pressure-sensitive adhesive according to claim 1, wherein the ratio of the acrylic polymer (A) to the acrylic polymer (B) is (A) / (B) = 95/5 to 5/95 by weight ratio. .   The pressure-sensitive adhesive according to claim 1 or 2, wherein the acrylic polymer (A) has a weight average molecular weight of 500,000 to 2,000,000, and the acrylic polymer (B) has a weight average molecular weight of 100,000 to 1,000,000. Agent.   The adhesive sheet provided with the base material and the adhesive layer formed from the adhesive in any one of Claims 1-3.   The pressure-sensitive adhesive sheet according to claim 7, wherein the substrate is an optical member.   The storage elastic modulus (G ′) of the pressure-sensitive adhesive layer at 23 ° C. is 0.1 to 5.0 MPa, and the storage elastic modulus (G ′) at 80 ° C. is 0.1 to 2.0 MPa. The pressure-sensitive adhesive sheet according to claim 4 or 5, characterized in that   The polarizing plate adhesive sheet containing a polarizing plate and the adhesive layer formed from the adhesive in any one of Claims 1-3.   A liquid crystal cell member comprising a glass layer, a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive according to claim 1, and an optical member.   The liquid crystal cell member according to claim 8, wherein the optical member is a polarizing plate.