KR102513258B1 - Adhesive agent and adhesive sheet - Google Patents

Abstract

[Problem] Provision of a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive sheet having excellent peelability and hardly lifting or peeling from an adherend after being exposed to a high-temperature environment or a high-temperature, high-humidity environment. [Means for Solution] (meth)acrylic acid alkyl ester (a-1) comprising an acrylic copolymer (A) and a crosslinking agent (B) and having an alkyl group having 1 to 3 carbon atoms as a monomer unit constituting the acrylic copolymer (A) ) 15 to 45% by weight of the unit, 54.4 to 84.8% by weight of the acrylic acid alkyl ester (a-2) having an alkyl group of 4 to 8 carbon atoms, and (meth)acrylic acid hydroxyester having an alkyl group of 2 to 4 carbon atoms ( a-3) contains 0.2 to 0.6% by weight of units, does not contain acidic group-containing monomer units and amide group-containing monomer units, and the acrylic copolymer (A) has a weight average molecular weight (Mw) of 1.2 to 1.6 million; , The degree of dispersion (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn), is 1.5 to 2.5.

Description

Adhesive and adhesive sheet {ADHESIVE AGENT AND ADHESIVE SHEET}

The present invention relates to a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and a liquid crystal cell member.

Liquid crystal display devices (hereinafter, referred to as LCDs) are used in various devices such as liquid crystal TVs, personal computer monitors, smart phones, tablets, and household and business electronic products. In addition, large-scale market expansion of LCDs is expected in the future due to an increase in size and rapid spread of touch panel terminals. In recent years, they are also used for in-vehicle devices such as car navigation systems and in-vehicle panels, and aircraft devices such as aircraft monitors. In these applications, LCDs require durability that can be used under harsh in-vehicle environments such as high-temperature, high-humidity atmospheres. Optical films such as polarizers (films), retardation plates (films), and light guide plates (films) having various optical functions are used in LCDs, and these optical films are attached to liquid crystal cells through adhesives.

A polarizing plate is generally a laminate having a structure in which a polyvinyl alcohol film (PVC layer), which is a polarizer, is sandwiched by a triacetyl cellulose film (TAC layer). Since these films each have a different rate of dimensional change, warping occurs in the laminate when placed under a high temperature or high temperature, high humidity atmosphere.

When a liquid crystal cell member having a configuration of, for example, a polarizing plate/adhesive layer/liquid crystal cell (top surface of the liquid crystal cell is glass) as the laminate is left in a high-temperature atmosphere, warpage resulting from the dimensional change rate between the constituent members of the polarizing plate occurs. , the problem that the polarizing plate is exfoliated from the glass may occur. In addition, the stress distribution of the liquid crystal cell member becomes non-uniform due to the warping, and as a result of stress concentrating on the peripheral end of the liquid crystal cell member, the so-called "light leakage phenomenon" in which light leaks from the four corners or peripheral end of the liquid crystal cell member Sometimes there is a problem called . The above problem similarly occurs even in a high-temperature, high-humidity atmosphere.

Further, in the recent LCD market, demands for high functionality such as enlargement, thinning, high viewing angle, and high contrast are increasing, and various materials constituting the display are required to have optical properties and durability higher than before.

For example, in a polarizing plate, in order to suppress deterioration of the polarizing plate (deterioration of the polarizer) due to moisture in a high-temperature, high-humidity environment, hydrophobicization of a conventionally used triacetyl cellulose film has been studied, and norbornene resin films and methyl methacrylic Substitution with low-polarity optical films such as late resin films and hydrophobic coating films is progressing. However, since these films have very low polarity, adhesives that have been used conventionally have poor adhesion to the surface of the film, resulting in problems with durability.

In addition, the LCD display system is being converted to an IPS display system instead of the conventional TN and VA display systems. In the IPS display method, the liquid crystal alignment is arranged in the horizontal direction on the display screen, so an improvement in the viewing angle is expected. In liquid crystal cells used in TN and VA display systems, which are conventional display devices, generally two transparent electrode substrates on which an alignment layer is formed are placed with the alignment layer on the inside by a spacer, and the periphery is sealed. It has a structure in which a liquid crystal material is sandwiched in the gap and a polarizing plate is disposed on the outer surfaces of the two transparent electrode substrates through an adhesive layer, respectively. For this reason, the surface to which the adhesive is in contact becomes glass. On the other hand, in the IPS display method, the transparent electrode substrate is not used inside the liquid crystal cell, but is installed on the uppermost surface of the liquid crystal cell with the alignment layer facing outward, and the polarizing plate is disposed on the alignment layer of the transparent electrode substrate with an adhesive layer interposed therebetween. has For this reason, the surface in contact with the pressure-sensitive adhesive becomes a transparent electrode substrate. Therefore, the pressure-sensitive adhesive is required to have corrosion resistance to the transparent electrode, and it is practically impossible to use a pressure-sensitive adhesive composed of acidic group-containing monomers. Currently, a pressure-sensitive adhesive containing an acidic group-containing monomer is used to secure durability, but the corrosion resistance to the transparent electrode is insufficient.

On the other hand, in the LCD manufacturing process, when a polarizing plate is bonded to an optical component such as a liquid crystal cell, when a difference occurs in the bonded position, etc., after a certain period of time has elapsed since bonding, the polarizing plate is peeled off and expensive liquid crystal It is being recovered and reused without damaging the cell. Therefore, the characteristic (rework property) which can re-peel a polarizing plate from a liquid crystal cell after a certain time elapses from application is calculated|required for an adhesive. In addition, in recent years, with the weight reduction of liquid crystal cells, the glass to be used has become thinner than before, and defects at the time of collection are likely to occur.

Then, in patent document 1, the technique of improving the adhesiveness to a low polarity film is disclosed by using the adhesive comprised from an alicyclic monomer and a functional group containing monomer. However, the pressure-sensitive adhesive described in Patent Literature 1 had a problem that not only the adhesion to the low-polarity film was high, but also the adhesion to glass was high, and there was no sufficient re-peelability (reworkability). In addition, since the amount of the functional group-containing monomer to be used is excessive, there is a problem that light leakage, floating, and peeling occur when left in a high-temperature, high-humidity environment.

Further, Patent Literature 2 discloses a technique for improving adhesion to a transparent conductive film by using an adhesive composed of an alicyclic monomer and a (meth)acrylic acid monomer that is an acidic group-containing monomer. However, since the pressure-sensitive adhesive described in Patent Document 2 contains an acidic group-containing monomer, when applied to a transparent conductive film, corrosion resistance is insufficient, so there is a problem that electrode corrosion such as a rise in resistance value and poor appearance occurs. .

Further, Patent Literature 3 discloses a technique for improving reworkability by using an adhesive obtained by blending a high molecular weight acrylic copolymer and a low molecular weight acrylic copolymer. However, although the pressure-sensitive adhesive described in Patent Document 3 has excellent reworkability, there is a problem that peeling occurs when left in a high-temperature, high-humidity environment for a long period of time.

Further, Patent Literature 4 discloses a technique of improving adhesion between a polarizing plate and glass to improve durability by blending a polymer having an active hydrogen-containing functional group and a polymer having an isocyanate group. However, since the pressure-sensitive adhesive described in Patent Document 4 has a wide dispersion degree (Mw/Mn) of 3 to 50, there is a problem that peeling occurs when sufficient cohesive force is not obtained and left in a high-temperature, high-humidity environment for a long period of time.

Japanese Unexamined Patent Publication No. 2005-053976 Japanese Unexamined Patent Publication No. 2012-201877 Japanese Unexamined Patent Publication No. 2013-10838 Japanese Unexamined Patent Publication No. 2015-205974

When the present invention is used for a pressure-sensitive adhesive sheet using an optical film as a base material of the pressure-sensitive adhesive, when attached to a conductive member such as a transparent conductive film or a metal circuit, it has excellent peelability, and after exposure to a high-temperature environment or a high-temperature and high-humidity environment, It is an object of the present invention to provide a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet using the pressure-sensitive adhesive that is unlikely to cause lifting or peeling from a conductive member of an adherend.

The present invention is a pressure-sensitive adhesive comprising an acrylic copolymer (A) and a crosslinking agent (B) for adhesively fixing an optical film on a conductive member, comprising the acrylic copolymer (A) and a crosslinking agent (B). 15 to 45% by weight of (meth)acrylic acid alkyl ester (a-1) unit having an alkyl group having 1 to 3 carbon atoms as a monomer unit constituting the acrylic copolymer (A), acrylic acid having an alkyl group having 4 to 8 carbon atoms A monomer containing 54.4 to 84.8% by weight of an alkyl ester (a-2) unit and 0.2 to 0.6% by weight of a (meth)acrylic acid hydroxyester (a-3) unit having an alkyl group having 2 to 4 carbon atoms, and containing an acidic group Unit and amide group-containing monomer unit are not contained, the weight average molecular weight (Mw) of the acrylic copolymer (A) is 1.20 to 1.6 million, and the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) Dispersity (Mw/Mn) is 1.5 to 2.5.

In addition, the present invention relates to the pressure-sensitive adhesive having a storage modulus of 0.5 to 1 MPa at 25 ° C. of the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive and an elastic retention rate represented by the following formula (1) of 60 to 100%.

Elastic retention rate (%) = G'(80 ℃) / G' (25 ℃) × 100　　　... Equation (1)

(However, in Formula (1), G' (80 ° C.) represents the storage modulus at 80 ° C., and G' (25 ° C.) represents the storage elastic modulus at 25 ° C., respectively.)

Further, the present invention relates to the pressure-sensitive adhesive in which the crosslinking agent (B) is an isocyanate compound.

Further, the present invention relates to the above pressure-sensitive adhesive further containing an organic silane compound (C) having an epoxy group or an epoxy cyclohexyl group.

Moreover, this invention relates to the adhesive sheet for optics provided with an optical film and the adhesive layer formed from the said adhesive.

Moreover, this invention relates to the polarizing plate adhesive sheet provided with the polarizing plate and the adhesive layer formed from the said adhesive.

Further, the present invention relates to a liquid crystal cell member comprising a conductive member and a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive.

According to the present invention, when an adhesive sheet using a pressure-sensitive adhesive is used to attach to a conductive member, it has excellent peelability and is less likely to lift or peel off from the conductive member after being exposed to a high-temperature environment or a high-temperature, high-humidity environment. You can get it.

Terms in this specification are explained. (meth)acrylic acid ester means acrylic acid ester and methacrylic acid ester. The acidic group-containing monomer unit is a carboxyl group-containing monomer, a sulfo group-containing monomer, or a phosphoric acid group-containing monomer. The adherend refers to the other party to which the pressure-sensitive adhesive sheet is bonded.

The present invention is a pressure-sensitive adhesive comprising an acrylic copolymer (A) and a crosslinking agent (B) for adhesively fixing an optical film on a conductive member, comprising the acrylic copolymer (A) and a crosslinking agent (B), and the acrylic copolymer As monomer units constituting the polymer (A), 15 to 45% by weight of (meth)acrylic acid alkyl ester (a-1) unit having an alkyl group of 1 to 3 carbon atoms and an alkyl acrylic acid ester having an alkyl group of 4 to 8 carbon atoms (a -2) 54.4 to 84.8% by weight of units and 0.2 to 0.6% by weight of (meth)acrylic acid hydroxyester (a-3) units having an alkyl group of 2 to 4 carbon atoms, acid group-containing monomer units and amide groups The acrylic copolymer (A) has a weight average molecular weight (Mw) of 1,200,000 to 1,600,000, and a degree of dispersion (Mw/Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). ) is 1.5 to 2.5.

<Acrylic Copolymer (A)>

The acrylic copolymer (A) in the present specification is characterized by not containing an acidic group-containing monomer unit as a constituting monomer unit. Since it does not contain an acidic group-containing monomer unit, when attached to a conductive member, an effect of preventing metal corrosion can be obtained, and an increase in electrode resistance value or poor appearance can be prevented.

The acrylic copolymer (A) is a (meth)acrylic acid alkyl ester (a-1) unit having an alkyl group having 1 to 3 carbon atoms as a monomer unit constituting the copolymer, and an acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms (a -2) It contains a (meth)acrylic acid hydroxyester (a-3) unit having a unit and an alkyl group of 2 to 4 carbon atoms.

The acrylic copolymer (A) is a (meth)acrylic acid alkyl ester (a-1) having an alkyl group of 1 to 3 carbon atoms, a (meth)acrylic acid alkyl ester (a-2) having an alkyl group of 4 to 8 carbon atoms, and a carbon number 2 It is synthesized by copolymerizing a monomer mixture containing (meth)acrylic acid hydroxyester (a-3) having an alkyl group of ~4.

The (meth)acrylic acid alkyl ester (a-1) having an alkyl group of 1 to 3 carbon atoms is a monomer having an alkyl group of 1 to 3 carbon atoms in the molecule (hereinafter sometimes abbreviated as monomer (a-1)). Since the cohesion force of an adhesive improves and a tough adhesive layer can be obtained by using a monomer (a-1), when exposed to a high-temperature atmosphere or a high-temperature, high-humidity atmosphere, lifting and peeling can be suppressed.

Examples of the monomer (a-1) include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and isopropyl methacrylate.

Among these monomers (a-1), methyl acrylate, methyl methacrylate, and ethyl acrylate are more preferable from the viewpoint of cohesive force and durability under a high-temperature atmosphere.

The monomer (a-1) preferably contains 15 to 45% by weight, more preferably 20 to 40% by weight, based on 100% by weight of the monomer mixture. When the content is 15% by weight or more, the cohesive force is further improved. In addition, when the content is 45% by weight or less, cohesion and stress relaxation properties can be achieved at a high level.

The acrylic acid alkyl ester (a-2) having an alkyl group of 4 to 8 carbon atoms is a monomer having an alkyl group of 4 to 8 carbon atoms in the molecule (hereinafter sometimes abbreviated as monomer (a-2)). When the monomer (a-2) is used, the flexibility of the pressure-sensitive adhesive is improved, the adhesion of the pressure-sensitive adhesive layer to the substrate (hereinafter referred to as substrate adhesion) is further improved, and when exposed to a high-temperature atmosphere or a high-temperature, high-humidity atmosphere, lifting and Peeling can be suppressed more.

Examples of the monomer (a-2) include butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate and the like.

Among these monomers (a-2), butyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate are preferable from the viewpoint of substrate adhesion and durability under a high-temperature and high-humidity atmosphere.

The monomer (a-2) preferably contains 54.4 to 84.8% by weight, more preferably 58 to 80% by weight, based on 100% by weight of the monomer mixture. When the content is 54.4% by weight or more, the substrate adhesion is further improved. Moreover, when content becomes 84.8 weight% or less, cohesive force and stress relaxation property can be compatible at a high level.

The (meth)acrylic acid hydroxyester (a-3) having an alkyl group of 2 to 4 carbon atoms is a monomer having an alkyl group of 2 to 4 carbon atoms and a hydroxyl group in the molecule (hereinafter abbreviated as monomer (a-3)). has exist). When the monomer (a-3) is used, a pressure-sensitive adhesive layer with good cohesive force can be obtained, lifting and peeling can be suppressed, and light leakage can also be suppressed.

The monomer (a-3) is, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy (meth)acrylate butyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like.

Among these monomers (a-3), 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 4-hydroxybutyl acrylate are more preferable from the viewpoints of substrate adhesion and durability under high-temperature and high-humidity atmospheres. .

The monomer (a-3) preferably contains 0.2 to 0.6% by weight, more preferably 0.2 to 0.4% by weight, based on 100% by weight of the monomer mixture. When the content is 0.2% by weight or more, the cohesive force is further improved. Moreover, when content becomes 0.6 weight% or less, cohesive force and stress relaxation property can be compatible at a high level.

Other vinyl monomers that can be used as monomer units constituting the acrylic copolymer (A) other than those described above include, for example, a monomer containing an epoxy group, a monomer containing an amino group, a monomer having an alkylene oxide unit, vinyl acetate, Vinyl crotonic acid, styrene, and acrylonitrile are preferable.

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

The monomer containing an amino group is, for example, (meth)acrylic acid monomethylaminoethyl, (meth)acrylic acid monoethyl aminoethyl, (meth)acrylic acid monomethyl aminopropyl, (meth)acrylic acid monoethyl aminopropyl, etc. ) acrylic acid monoalkyl amino esters.

A monomer having an alkylene oxide unit is a monomer having a unit such as ethylene oxide or propylene oxide. The monomer having an alkylene oxide unit is, for example, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-phenoxyethyl acrylate, methoxy polyethylene glycol (meth) acrylate ester, ethoxy polyethylene glycol (meth ) acrylic acid esters, methoxy polypropylene glycol (meth) acrylic acid esters, ethoxy polypropylene glycol (meth) acrylic acid esters, phenoxy polyethylene glycol (meth) acrylic acid esters, and phenoxy polypropylene glycol (meth) acrylic acid esters. .

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 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, based on 100% by weight of the monomer mixture. When the content is 0.1% by weight or more, the cohesive force is further improved. Moreover, when content becomes 10 weight% or less, cohesive force and stress relaxation property can be compatible at a high level.

The acrylic copolymer (A) does not contain an amide group-containing monomer unit as a constituting monomer unit. Since the pressure-sensitive adhesive of the present invention does not contain an amide group-containing monomer unit, when the pressure-sensitive adhesive sheet is attached to an adherend and then exposed to a high-temperature, high-humidity atmosphere, the pressure-sensitive adhesive layer becomes difficult to absorb moisture, so lifting and peeling can be suppressed. . In addition, the amide group-containing monomer unit refers to (meth)acrylamide and derivatives thereof.

1.2 million - 1.6 million are preferable, and, as for the weight average molecular weight of an acrylic copolymer (A), 1.3 million - 1.6 million are more preferable. Since cohesive force improves more because it exists in the range of 1.2 million - 1.6 million, lifting and peeling can be suppressed more, and stress relaxation property also improves more. Further, the molecular weight distribution of the acrylic copolymer (A) (molecular weight distribution representing the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn)) is preferably in the range of 1.5 to 2.5, and 1.8 to 2.3 The range of is more preferable. By being in the above range, it is difficult to cause lifting and peeling after exposure to a high-temperature environment or a high-temperature, high-humidity environment, and the adhesive strength is further improved. In addition, the above weight average molecular weight and number average molecular weight are values in terms of polystyrene measured by a gel permeation chromatography (GPC) method. Details of the method for measuring GPC are described in Examples.

The acrylic copolymer (A) is synthesized by copolymerizing a monomer mixture. Known polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, and suspension polymerization can be used for copolymerization, but solution polymerization is preferred. As for the solvent used by solution polymerization, acetone, methyl acetate, ethyl acetate, toluene, xylene, anisole, methyl ethyl ketone, and cyclohexanone are preferable, for example. As for polymerization temperature, the boiling point reaction of 60-120 degreeC is preferable. The polymerization time is preferably about 5 to 12 hours.

The polymerization initiator is preferably a radical polymerization initiator. The radical polymerization initiator is not particularly limited as long as it is a compound capable of generating radicals at the polymerization temperature, and peroxides and azo compounds are common.

Peroxides include, for example, di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, α,α'-bis(t-butyl peroxy-m-isopropyl) benzene, 2,5 -dialkyl peroxides such as di(t-butyl peroxy)hexyne-3;

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

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

2,2-bis(4,4-di-t-butyl peroxycyclohexyl) propane, 1,1-bis(t-butyl peroxy) 3,3,5-trimethylcyclohexane, 1,1-bis( peroxy ketals such as t-butyl peroxy) cyclohexane, n-butyl-4,4-bis (t-butyl peroxy) valerate;

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

diacyl peroxides such as benzoyl peroxide, decanoyl peroxide, laurolyl peroxide, and 2,4-dichlorobenzoyl peroxide;

and peroxydicarbonates such as bis(t-butylcyclohexyl)peroxydicarbonate.

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

2,2'-azobisvale such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile) Lonitrile;

2,2'-azobispropionitrile such as 2,2'-azobis(2-hydroxymethyl propionitrile);

1,1'-azobis-1-alkane nitriles such as 1,1'-azobis(cyclohexane-1-carbonitrile);

A polymerization initiator can be used individually or in combination of 2 or more types.

The 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.

<Crosslinking agent (B)>

Since the pressure-sensitive adhesive of the present invention contains a crosslinking agent (B), when processed into a pressure-sensitive adhesive sheet, the cohesive strength of the pressure-sensitive adhesive layer is caused by a crosslinking reaction with the crosslinkable functional groups (e.g., hydroxyl group, acidic group) of the acrylic copolymer (A). When this improves and is exposed to a high-temperature atmosphere or a high-temperature, high-humidity atmosphere, lifting and peeling can be suppressed while maintaining high transparency.

The crosslinking agent (B) is, for example, an isocyanate compound, an epoxy compound, an aziridine compound, an acid anhydride group-containing compound, a carbodiimide compound, an N-methylol group-containing compound, and a metal chelate compound.

The isocyanate-based compound is an isocyanate monomer having two or more isocyanate groups. The isocyanate-based compound is preferably an isocyanate monomer such as an aromatic polyisocyanate, an aliphatic polyisocyanate, an aromatic aliphatic polyisocyanate, or an alicyclic polyisocyanate, and a biuret form, a nurate form, and an adect form thereof.

Aromatic polyisocyanates include, for example, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2, 4-Torylene diisocyanate, 2,6-Torylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate , 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate.

Aliphatic polyisocyanate, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (alias: HMDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate , 1,3-butylene diisocyanate, dodeca methylene diisocyanate, and 2,4,4-trimethyl hexamethylene diisocyanate.

Aromatic aliphatic polyisocyanates include, for example, ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1, 4-diethylbenzene, 1,4-tetramethyl xylylene diisocyanate, and 1,3-tetramethyl xylylene diisocyanate.

Alicyclic polyisocyanate, for example, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (alias: IPDI, isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclo Hexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1, 4-bis(isocyanate methyl) cyclohexane.

The biuret form of an isocyanate monomer is a self-condensate having a biuret bond formed by self-condensation of the isocyanate monomer. As for the biuret body of an isocyanate monomer, the biuret body of hexamethylene diisocyanate etc. are mentioned, for example.

The nurate body of an isocyanate monomer is a self-condensation product which has the nurate bond which the isocyanate monomer self-condensed. The nurate body of the ternary of an isocyanate monomer is, for example, the nurate body of the ternary of hexamethylene diisocyanate, the nurate body of the ternary of isophorone diisocyanate, the nurate body of the ternary of torylene diisocyanate, for example etc. can be mentioned.

An adduct of an isocyanate monomer is a bifunctional or higher functional isocyanate compound in which an isocyanate monomer and a bifunctional or higher molecular weight active hydrogen-containing compound reacted. The adduct of the isocyanate monomer is, for example, a compound obtained by reacting trimethylolpropane and hexamethylene diisocyanate, a compound obtained by reacting trimethylolpropane and torylene diisocyanate, and trimethylolpropane and xylylene diisocyanate. A compound made to react, a compound made by reacting trimethylolpropane and isophorone diisocyanate, and a compound made by reacting 1,6-hexanediol and hexamethylene diisocyanate are exemplified.

The isocyanate-based 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-weight active hydrogen-containing compound. Isocyanate-based compounds include, for example, trimethylolpropane adduct of hexamethylene diisocyanate, trimethylolpropane adduct of torylene diisocyanate, trimethylolpropane adduct of isophorone diisocyanate, and isophorone diisocyanate. A nurate body and a trimethylolpropane adduct of xylylene diisocyanate are preferable, and an aromatic aliphatic system such as a trimethylolpropane adduct of torylene diisocyanate and a trimethylolpropane adduct of xylylene diisocyanate. A polyisocyanate compound is more preferable.

Epoxy compounds, 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, trimethylolpropane triglycidyl ether, diglycidyl aniline, N,N,N',N'-tetraglycidyl-m-xylylene diamine, 1, 3-bis(N,N'-diglycidylaminomethyl) cyclohexane, N,N,N',N'-tetraglycidyl aminophenyl methane, and the like.

An aziridine compound, for example, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxylate), N,N'-toluene-2,4-bis(1-aziridinecarboxy d), bis isophthaloyl-1-(2-methylaziridine), tri-1-aziridinyl phosphine oxide, N,N'-hexamethylene-1,6-bis(1-aziridine carboxide) , 2,2'-bishydroxymethyl butanol-tris [3-(1-aziridinyl) propionate], trimethylolpropane tri-β-aziridinylpropionate, tetramethylolmethane tri- β-aziridinylpropionate, tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, 4,4′-bis(ethyleneiminocarbonylamino)diphenyl Methane etc. are mentioned.

The carbodiimide compound is preferably a high molecular weight polycarbodiimide produced by subjecting a diisocyanate compound to a decarbonation condensation reaction in the presence of a carbodiimidization catalyst.

Commercially available products of the carbodiimide compound include, for example, the Carbodilite series manufactured by Nissin Spinning Co., Ltd. Among them, Carbodilite V-01, 03, 05, 07, and 09 are preferable 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. Examples of the acid anhydride group-containing compound include tetracarboxylic dianhydride, hexacarboxylic dianhydride, hexacarboxylic dianhydride, and maleic anhydride copolymer resins. In addition, polycarboxylic acids, polycarboxylic acid esters, polycarboxylic acid half esters, etc., which can be completed with an anhydride via dehydration during the reaction, are included in the "acid anhydride group-containing compound" of the present invention.

Tetracarboxylic dianhydride, for example, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, oxydiphthalic dianhydride, diphenylsulfone tetracarboxylic dianhydride , diphenyl sulfide tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, perylene tetracarboxylic dianhydride, and naphthalene tetracarboxylic dianhydride.

The metal chelate compound is, for example, a coordination compound of a multivalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium with acetylacetone or ethyl acetoacetate. Examples of the metal chelate compound include aluminum ethyl acetoacetate/diisopropylate, aluminum trisacetylacetate, aluminum bisethylacetoacetate/monoacetylacetate, and aluminum alkylacetoacetate/diisopropylate.

The crosslinking agent (B) is more preferable because the isocyanate-based compound can achieve both substrate adhesion and re-peelability at a high level.

A crosslinking agent (B) can be used individually or in combination of 2 or more types.

The crosslinking agent (B) is preferably used in an amount of 0.05 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). When the content is 0.05 parts by weight or more, the cohesive force is further improved. In addition, when the content is 20 parts by weight or less, cohesion and stress relaxation properties can be achieved at a high level.

<Organic silane compound (C)>

The pressure-sensitive adhesive of the present invention may further contain an organic silane compound (C) having an epoxy group or an epoxy cyclohexyl group (hereinafter sometimes abbreviated as compound (C)). The organic silane compound (C) can further suppress lifting and peeling and further suppress light leakage by forming a covalent bond or a hydrogen bond between the functional groups present on the surface of the substrate.

The organic silane compound (C) is preferably an organic silane monomer or an organic silane oligomer.

The organic silane monomer is, for example, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropylmethyl dimethoxysilane, 3-glycidoxypropyl dimethylmethoxysilane, 3-glycidoxypropyl trie Toxysilane, 3-glycidoxypropylmethyl diethoxysilane, and 3-glycidoxypropyldimethyl ethoxysilane are exemplified. Especially, 3-glycidoxypropyl triethoxysilane and 3-glycidoxypropyl methyl diethoxysilane are more preferable.

As the organic silane oligomer, a compound represented by the following formula [I] or formula [II] is preferable.

In the formula, p, q, r, s, and t are integers representing repeating units, and 0≤p≤50, 5≤q≤50, 5≤r≤50, 0≤s≤50, 5≤t=50 , 5≤p+q≤100, 10≤r+s+t≤150. X ₁ to X ₃ and X ₅ , X ₆ each independently represent an alkyl group, X ₄ represents a divalent organic residue having 1 to 10 carbon atoms, Y represents an alkoxyl group, and Z represents an epoxy group or an epoxy cyclohexyl group indicates

In the formulas [I] and [II], Y is an alkoxy group, and examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentaoxy group. Among them, a methoxy group, an ethoxy group, a propoxy group, and a butoxy group are preferable, and a methoxy group and an ethoxy group are more preferable.

X ₁ to X ₃ and X ₅ , X ₆ each independently represent an alkyl group or an aryl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group. As an aryl group, a phenyl group, a toryl group, a xylyl group, a naphthyl group, etc. are mentioned. Among them, a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group are preferable, and a methyl group and a phenyl group are more preferable.

X ₄ is a divalent organic residue having 1 to 10 carbon atoms, and is selected from a methylene group, a 1,2-ethylene group, a 1,3-propylene group, a 1,4-butylene group, a 1,5-pentylene group, and a 1,6-hexyl group. Straight chain alkylene groups such as silene group, 1,7-heptylene group, 1,8-octylene group, 1,9-nonylene group, 1,10-decanylene group, 1,1-ethylene group, 1,2-propylene group , 1,1-propylene group, 1-methyl-1,3-butylene group, 2-methyl-1,3-butylene group, 1,2-dimethyl-1,2-butylene group, 1,1-butylene group, Branched alkylene groups, such as an ethyl- 1, 2- ethylene group, etc. are mentioned. Among these alkylene groups, a straight-chain alkylene group is preferable, and a methylene group, a 1,2-ethylene group, a 1,3-propylene group, and a 1,4-butylene group are more preferable.

Z represents an epoxy group or an epoxy cyclohexyl group.

In addition, an epoxy cyclohexyl group is a group represented by the following formula [III].

p is an integer within the range of 0≤p≤50, preferably an integer within the range of 5≤p≤40, and more preferably an integer within the range of 10≤p≤30.

q is an integer within the range of 5≤q≤50, preferably an integer within the range of 10≤q≤50, more preferably an integer within the range of 10≤q≤40.

r is an integer within the range of 5≤r≤50, preferably an integer within the range of 10≤r≤50, and more preferably an integer within the range of 10≤r≤40.

s is an integer within the range of 0≤s≤50, preferably an integer within the range of 10≤s≤50, and more preferably an integer within the range of 10≤s≤40.

t is an integer within the range of 5≤t≤50, preferably an integer within the range of 10≤t≤50, and more preferably an integer within the range of 10≤t≤40.

p+q is an integer within the range of 5≤p+q≤100, preferably an integer within the range of 10≤p+q≤80, more preferably an integer within the range of 20≤p+q≤60.

r+s+t is an integer within the range of 10≤r+s+t≤150, preferably an integer within the range of 20≤r+s+t≤130, and more preferably an integer within the range of 30≤r+s+t≤100.

In the organosilane compound (C), the compound represented by the formula [I] is a commercially available product, for example, X-22-343, KF-101, KF-1001, X-22-2000, X-22-4741 , KF-1002, X-22-2046, KF-102, and KF-1005 (all manufactured by Shin-Etsu Silicone Co., Ltd.).

Among the organic silane compounds (C), the compound represented by the formula [II] is a commercial product, for example, X-41-1053, X-41-1059A, KR-516, X-24-9589, X-24 -9590, X-41-1056 (both manufactured by Shin-Etsu Silicon Co., Ltd.), and the like.

The organosilane compound (C) may be used singly or in combination of two or more.

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

The storage elastic modulus (G') at 25°C of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive of the present invention is preferably 0.5 to 1 MPa, more preferably 0.6 to 0.9 MPa. Since the storage elastic modulus (G') at 25°C is 0.5 MPa or more, lifting and peeling in a high-temperature atmosphere can be further suppressed. In addition, since the storage elastic modulus (G') at 25°C is 1 MPa or less, lifting and peeling in a high-temperature, high-humidity atmosphere can be further suppressed.

It is preferable that the elastic retention rate represented by following formula (1) of the adhesive layer formed from the adhesive of this invention is 60 to 100%, and it is more preferable that it is 60 to 90%. Since the elastic retention is 60 to 100%, lifting and peeling in a high-temperature atmosphere and a high-temperature, high-humidity atmosphere can be more suppressed.

Elastic retention rate (%) = G'(80 ℃) / G' (25 ℃) × 100　　　... Equation (1)

In the above formula, G' (80 °C) represents the storage modulus at 80 °C, and G' (25 °C) represents the storage modulus at 25 °C. In addition, the detail of the measuring method of storage elastic modulus (G') is described in an Example.

The pressure-sensitive adhesive of the present invention may contain various resins, oils, softeners, dyes, pigments, antioxidants, ultraviolet absorbers, weathering stabilizers, plasticizers, fillers, anti-aging agents and antistatic agents as optional components, as long as the effects of the present invention are not impaired. can be combined.

The pressure-sensitive adhesive of the present invention is suitable as a pressure-sensitive adhesive for adhesively fixing an optical film to a conductive member, as well as a pressure-sensitive adhesive layer constituting an organic EL display, various plastic sheets, general labels and seals, paints, elastic wall materials, coating film waterproofing materials, flooring materials, and imparting tackiness. Adhesives, adhesives for laminated structures, sealing agents, molding materials, coating agents for surface modification, 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 curing resin, high solid paint, thermosetting elastomer, microcellar, textile processing agent, plasticizer, sound absorption material, damping material, surfactant, gel coat agent, artificial marble Resin for artificial marble, impact resistance imparting agent, resin for ink, film (laminate adhesive, protective film, etc.), resin for tempered glass, reactive diluent, various molding materials, elastic fibers, artificial leather, synthetic leather, etc. As a raw material, In addition, it can be used very usefully as various resin additives and raw materials thereof.

The pressure-sensitive adhesive of the present invention is a base material and. It is preferable to use it as an adhesive sheet provided with the adhesive layer formed from the adhesive. An adhesive layer can be formed by coating an adhesive. On the surface of the pressure-sensitive adhesive layer that is not in contact with the base material, a release sheet is usually applied until immediately before using the pressure-sensitive adhesive sheet to prevent adhesion of foreign substances.

At the time of coating, the viscosity of the pressure-sensitive adhesive can be adjusted using a suitable solvent. Moreover, the viscosity can also be adjusted by heating the adhesive.

Examples of the solvent include hydrocarbon solvents such as toluene, xylene, hexane and heptane; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone and methyl ethyl ketone; halogenated hydrocarbons such as dichloromethane and chloroform; system solvent; Ether system solvents, such as diethyl ether, methoxytoluene, and a dioxane; are mentioned.

The pressure-sensitive adhesive layer is formed by coating and drying the pressure-sensitive adhesive by a known method. Examples of the coating method include a Meyer bar, an applicator, 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. As for the drying method, hot-air drying, an infrared rays, or a reduced-pressure method is mentioned, for example. The drying temperature is usually about 60 to 160°C.

The thickness of the pressure-sensitive adhesive layer is preferably 0.1 to 300 μm, and more preferably 1 to 100 μm. Adequate adhesive force can be obtained by adjusting to 0.1-300 micrometers.

In a release sheet, a known release layer formed from a silicone-based compound or the like is usually formed on a film or paper substrate.

The thickness of the peelable sheet is usually about 10 to 200 μm.

As for the base material, plastic, paper, metal foil, etc. are mentioned, for example. As for the shape of the base material, a sheet, a film, a foam or the like may be used.

The thickness of the substrate is about 5 to 200 μm.

<Adhesive sheet for optics>

The optical adhesive sheet of the present invention includes an optical film and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive of the present invention.

As the substrate, an optical film is used. A laminated body obtained by laminating a plurality of optical films can also be used as the base material.

The optical film is, for example, a polyolefin resin such as polyvinyl alcohol, triacetyl cellulose, polypropylene, polyethylene, polycyclo olefin, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc. polyester resins, polyacrylic resins such as polymethyl methacrylate and polybutyl methacrylate, polycarbonate resins, polynorbornene resins, polyarylate resins, polyacrylic resins, polyphenylene sulfide resins, polystyrene resins, poly Amide type resin, polyimide type resin, epoxy type resin, etc. are mentioned.

It is more preferable to use a low-polarity optical film among the said optical films for a base material. Here, the low-polarity optical film is an optical film having a contact angle with water (water contact angle) of 70° or more. The low polarity optical film is, for example, polycycloolefin resin (water contact angle 90 °), polycarbonate resin (water contact angle 80 °), polynorbornene resin (water contact angle 89 °), polymethyl methacrylate resin (water contact angle 89 °) contact angle of 80°).

The method of measuring the water contact angle is to leave the various optical films at 23 ° C. and 50% RH for 24 hours, and then use an automatic contact angle meter (model CA-V type) manufactured by Kyowa Interface Science Co., Ltd. by the droplet method, 23 Under an atmosphere of °C and 50% RH, 2.0 µL of distilled water is dropped onto the film, and the angle formed by the tangent between the film and the end of the droplet 1 second after the droplet is dropped is measured.

The adhesive sheet for optics of this invention can be used suitably for bonding of an optical member. That is, it is preferable to use an optical member for the base material. Examples of the optical member include a polarizing plate, a retardation film, an elliptically polarizing film, an antireflection film, a brightness enhancing film, and glass.

<Adhesive sheet for polarizing plate>

The polarizing plate adhesive sheet of the present invention includes a polarizing plate and a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive.

The polarizing plate pressure-sensitive adhesive sheet is a pressure-sensitive adhesive sheet using a polarizing plate in place of the optical film included in the pressure-sensitive adhesive sheet for optics. Since the pressure-sensitive adhesive sheet for polarizing plate includes the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive of the present invention, when it is left in a high-temperature atmosphere and a high-temperature, high-humidity atmosphere after being applied to an adherend, the pressure-sensitive adhesive layer has good stress relaxation properties, resulting in warping of the polarizing plate. Light omission can be suppressed.

A polarizing plate is, for example, a known known structure formed by using a polyvinyl alcohol film as a polarizer and bonding a film selected from a polycycloolefin film, a polycarbonate film, a polynorbornene film, and a polymethyl methacrylate film using an adhesive on both sides of the polarizer. is the absence of

The thickness of the polarizing plate is about 50 to 300 μm.

<Liquid crystal cell member>

The liquid crystal cell member of the present invention includes a conductive member and an adhesive layer formed of an adhesive.

The conductive member is one of the members constituting the liquid crystal cell, and is provided with a conductive layer such as a transparent conductive film such as ITO and a metal circuit formed on a substrate. Since the conductive layer is formed by sputtering, vapor deposition, etc., it has a thickness of about 100 to 5000 Å.

As for a base material, a glass plate is mentioned, for example. The thickness of the substrate is about 25 to 500 mm.

Since the liquid crystal cell member is provided with an adhesive layer formed from the adhesive of the present invention, the conductive layer is less likely to corrode.

The use of the pressure-sensitive adhesive sheet of the present invention described above can also be applied to various electronics-related members such as LCDs, organic EL displays, plasma displays, touch screen panels, electrode peripheral members, and protective films.

Example

Next, examples of the present invention will be shown and described in more detail, but the present invention is not limited thereto. In the examples, unless otherwise specified, "part" indicates "part by weight" and "%" indicates "% by weight", respectively.

<Synthesis Example 1: Acrylic Copolymer>

15 parts of methyl acrylate (MA), 84.7 parts of butyl acrylate (BA), and 2 parts of acrylic acid were placed in a reaction vessel (hereinafter simply referred to as "reaction vessel") equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube. - 0.3 part of hydroxyethyl (HEA), 100 parts of acetone, and 0.01 part of 2,2'-azobisisobutyronitrile (hereinafter referred to as AIBN) were introduced, and the air in the reaction vessel was substituted with nitrogen gas. Thereafter, the reaction was initiated by heating to 65°C while stirring in a nitrogen atmosphere. Then, the reaction solution was reacted at reflux temperature for 4 hours. After completion of the reaction, it was cooled and diluted with ethyl acetate to obtain a copolymer solution having a non-volatile content of 30% and a viscosity of 6000 mPa·s. In addition, when the weight average molecular weight (Mw) of the acrylic copolymer was measured using GPC, the weight average molecular weight was 1.5 million and the degree of dispersion (Mw/Mn) was 2. The obtained copolymer is used as an acrylic copolymer (A-1).

<Synthesis Examples 2 to 27>

An acrylic copolymer was synthesized in the same manner as in Synthesis Example 1, except that various raw materials were changed according to the weight ratios in Tables 1 and 2. Table 1 and Table 2 show the weight average molecular weight (Mw) and degree of dispersion (Mw/Mn) of the obtained acrylic copolymer. In addition, blanks in the tables indicate that they are not blended.

<Measurement of weight average molecular weight (Mw)>

The weight average molecular weight (Mw) was measured using GPC "LC-GPC system" manufactured by Shimadzu Corporation. The weight average molecular weight (Mw) was determined by conversion using polystyrene of known molecular weight as a standard material.

Device name: Shimadzu Manufacturing Co., Ltd., LC-GPC system "Prominence"

Column: 4 GMHXL made by the same company and 1 HXL-H made by the same company were connected in series.

Mobile phase solvent: tetrahydrofuran

Flow rate: 1.0ml/min

Column temperature: 40 ° C

(Example 1)

The combination of the copolymer solution obtained in Synthesis Example 1 as the acrylic copolymer (A) (an amount of 100 parts of the acrylic copolymer (A-1) in the solution) and trimethylolpropane of torylene diisocyanate as the crosslinking agent (B). 0.5 part of the organic silane compound, 0.1 part of 3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-Etsu Silicone Co., Ltd.) was blended, and ethyl acetate in an amount such that the non-volatile content was 20% was blended to obtain an adhesive. .

<Preparation of optical adhesive sheet and polarizer adhesive sheet>

The adhesive was coated on a polyethylene terephthalate peelable sheet having a thickness of 38 μm (Cerapeel MF: manufactured by Toray Film Processing Co., Ltd.) so that the thickness after drying was 25 μm, and dried at 100 ° C. for 2 minutes to form an adhesive layer. . Next, one side of a cycloolefin film (Zeonor: product of Zeon, Japan, thickness 100 μm) was bonded to this pressure-sensitive adhesive layer to obtain an optical pressure-sensitive adhesive sheet having a configuration of “release film / pressure-sensitive adhesive layer / cycloolefin film” . Next, the obtained optical adhesive sheet was aged for one week at a temperature of 25°C and a relative humidity of 55% to obtain a laminate (hereinafter referred to as laminate A).

In addition, using a polarizing plate (layer composition: triacetyl cellulose film / polyvinyl alcohol film / polymethyl methacrylate film) instead of the cycloolefin film, the pressure-sensitive adhesive layer and the polymethyl methacrylate film surface of the polarizing plate are bonded so that they are in contact. A polarizing plate adhesive sheet having a configuration of "release film/adhesive layer/polarizing plate" was obtained. Next, the obtained polarizing plate adhesive sheet was aged for 1 week under conditions of a temperature of 25°C and a relative humidity of 55% to obtain a laminate (hereinafter, referred to as laminate B).

(Examples 2 to 35, Comparative Examples 1 to 12)

In the replacement of the materials used in Example 1, the adhesives were obtained in the same manner as in Example 1, except that the materials and compounding amounts shown in Table 3, Table 4, Table 5, Table 6 and Table 7 were respectively changed. Further, in the same manner as in Example 1, an optical adhesive sheet and a laminate were respectively obtained.

Table 3, Table 4, Table 5 and Table 6 show crosslinking agents (B) used in Examples and Comparative Examples. Table 7 also shows organosilane compounds (C) used in Examples and Comparative Examples.

(Comparative Examples 13 to 18)

As a comparative example, an optical adhesive sheet and a laminate were obtained in the same manner as in the method for preparing the optical adhesive sheet and polarizing plate adhesive sheet in Example 1 of the present specification, using the adhesive described in the examples of the following patent documents.

Comparative Example 13: Adhesive of Example 2 described in Japanese Unexamined Patent Publication No. 2005-053976

Comparative Example 14: Adhesive of Example 6 described in Japanese Unexamined Patent Publication No. 2005-053976

Comparative Example 15: Adhesive of Example 2 described in Japanese Unexamined Patent Publication No. 2012-201877

Comparative Example 16: Adhesive of Example 3 described in Japanese Unexamined Patent Publication No. 2012-201877

Comparative Example 17: Adhesive of Example 1 described in Japanese Unexamined Patent Publication No. 2013-10838

Comparative Example 18: Adhesive of Example 3 described in Japanese Unexamined Patent Publication No. 2013-10838

Comparative Example 19: Adhesive of Example 3 described in Japanese Unexamined Patent Publication No. 2015-205974

Comparative Example 20: Adhesive of Example 5 described in Japanese Unexamined Patent Publication No. 2015-205974

The obtained layered product A was evaluated according to the following method.

(1) Evaluation of heat resistance and moist heat resistance 1

The layered product A obtained above was cut into a size of 930 mm in width and 523 mm in length (corresponding to 42 inches). Next, the peelable sheet was peeled off from the cut layered product A and adhered to an ITO sputtered glass plate (type 80Ω: manufactured by Nippon Glass Co., Ltd.) using a laminator. Subsequently, a measurement sample was obtained by holding the glass plate with the layered product A attached thereto for 20 minutes in an autoclave under conditions of 50° C. and 5 atm to bring the members into close contact. This measurement sample was evaluated for heat resistance as resistance evaluation in a high-temperature atmosphere. That is, after the measurement sample was left at 105°C for 1000 hours, the presence or absence of foaming, floating, and peeling was visually observed.

Moreover, heat-and-moisture resistance was evaluated for the measurement sample as resistance evaluation in a high-temperature, high-humidity atmosphere. That is, after the measurement sample was left at 85°C and 85% relative humidity for 500 hours, the presence or absence of foaming, lifting, and peeling was visually observed. Heat resistance and heat-and-moisture resistance were all evaluated based on the following criteria.

◎: Foaming, floating, and peeling were not recognized at all, which was good.

○: One of 1 mm or less foaming, floating, and peeling is recognized, but there is no problem in practical use.

x: There is foaming, floating, and peeling all over, and it cannot be used.

(2) Corrosion resistance evaluation method

As an evaluation of corrosion resistance, a PET film (IPF-05H125: manufactured by Gunze Co., Ltd.) having an ITO transparent conductive film with a film thickness of 5 μm was cut into a 40 mm wide and 100 mm long ITO transparent conductive film having a width of 40 mm and a length of 160 mm. , The layered product A was adhered by peeling off the release film. Subsequently, this laminate was held in an autoclave at 50°C and 5 atm for 20 minutes to adhere each member to obtain a measurement sample having a total structure of cycloolefin film/pressure-sensitive adhesive layer/ITO film.

An electrode was connected to both ends of this measurement sample, and the initial electrical resistance value was measured. In addition, after leaving the measurement sample at 85°C and 85% relative humidity for 1000 hours, the electrical resistance value after the passage of time in the same manner as described above was measured. Corrosion resistance evaluation was all evaluated based on the following criteria. In addition, for the measurement of the electrical resistance value, Laresta-GP = MCP-T600 (manufactured by Mitsubishi Chemical Corporation) was used.

Electrical resistance change rate = (electrical resistance value after time lapse/initial electrical resistance value)

4: No change in electrical resistance was observed, which was particularly good.

3: The electrical resistance change rate is less than 2.0 and is good.

2: The electrical resistance change rate is 2.0 or more and less than 3.0, but there is no problem in practical use.

1: The electrical resistance change rate is 3.0 or more and cannot be used.

(3) Evaluation of heat resistance and moist heat resistance 2

The laminate B obtained above was cut into a size of 930 mm in width and 523 mm in length (corresponding to 42 inches). Next, the peelable sheet was peeled off from the cut laminate B and adhered to an ITO sputtered glass plate (type 80Ω: manufactured by Japan Glass Co., Ltd.) using a laminator. Subsequently, a measurement sample was obtained by holding the glass plate with the layered product B attached thereto for 20 minutes in an autoclave under conditions of 50° C. and 5 atm, and bringing the respective members into close contact. This measurement sample was evaluated for heat resistance as resistance evaluation in a high-temperature atmosphere. That is, after the measurement sample was left at 105°C for 1000 hours, the presence or absence of foaming, floating, and peeling was visually observed.

Moreover, heat-and-moisture resistance was evaluated for the measurement sample as resistance evaluation in a high-temperature, high-humidity atmosphere. That is, after leaving the measurement sample at 85°C and 95% relative humidity for 1000 hours, the presence or absence of foaming, floating, and peeling was visually observed. Heat resistance and heat-and-moisture resistance were all evaluated based on the following criteria.

◎: Foaming, floating, and peeling were not recognized at all, which was good.

○: One of 0.5 mm or less foaming, floating, and peeling is recognized, but there is no problem in practical use.

x: There is foaming, floating, and peeling all over, and it cannot be used.

(4) Light Missing Evaluation

The laminate B obtained above was cut into a size of 930 mm in width and 523 mm in length (corresponding to 42 inches). Next, the peelable sheet is peeled off from the cut laminate B, and two layers of laminate B are adhered to both sides of an ITO sputtered glass plate (type 80Ω: manufactured by Nippon Glass) using a laminator so that the absorption axes of the polarizing plates are orthogonal to each other. obtained a compress. Subsequently, measurement samples were obtained by holding the compressed product in an autoclave at 50° C. and 5 atm for 20 minutes to adhere each member. After this measurement sample was allowed to stand at 105°C for 1000 hours, light loss when light was transmitted through the polarizing plate was visually observed. The light omission property was evaluated based on the following criteria.

◎: No discoloration, good.

○: Although discoloration is recognized in only a part, total discoloration is not recognized, and there is no problem in practical use.

×: There is discoloration all over and cannot be used.

(5) Evaluation of re-peelability

The layered product B obtained above was cut into a size of 100 mm in width and 100 mm in length. Next, the peelable sheet was peeled off from the cut laminate B and attached to an ITO sputtered glass plate (variety 80Ω: manufactured by Japan Glass Plate) using a laminator. Subsequently, a measurement sample was obtained by holding the sample in an autoclave at 50° C. and 5 atmospheric pressure for 20 minutes to adhere each member. After leaving this measurement sample at 105°C for 7 days, using a tensile tester ("Tensilon" manufactured by Orientec Co., Ltd.) in an environment of 23°C and 50% relative humidity, at a speed of 300 mm/min in the 180° direction. A peel test was conducted by pulling with . Next, the opacity of the glass surface after peeling was visually observed and evaluated based on the following criteria.

○: Paste remains, and opacity is not observed, which is good.

x: Glue remains, opacity is recognized, and it is not practical.

(6) Storage modulus (G') and elastic retention

An adhesive layer was formed by applying the obtained adhesive to a peelable sheet so that the thickness after drying was 30 μm, and drying. 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 in an autoclave, and then a hole having a diameter of 8 mm was pierced to obtain a cylindrical test piece. The storage elastic modulus (G') of the test piece was measured under the following conditions.

Measuring device: "DYNAMIC, ANALYZER, RDA III", a dynamic viscoelasticity measuring device manufactured by T.A. Instrument Japan Co., Ltd.

Frequency: 1Hz

Temperature: 25, 80℃

Moreover, the elastic retention was calculated based on the following formula (1) from the storage elastic modulus obtained by the measurement.

Elastic retention rate (%) = G'(80 ℃) / G' (25 ℃) × 100　　　... Equation (1)

(However, in Formula (1), G' (80 ° C.) represents the storage modulus at 80 ° C., and G' (25 ° C.) represents the storage elastic modulus at 25 ° C., respectively.)

As shown in Examples 1 to 35 from the results of Tables 8 and 9, the pressure-sensitive adhesive of the present invention is excellent in durability, light omission property, and re-peelability in a high-temperature atmosphere and a high-temperature, high-humidity atmosphere. On the other hand, Comparative Examples 1 to 20 could not satisfy all of the above characteristics.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

Claims (7)

An adhesive containing an acrylic copolymer (A) and a crosslinking agent (B) for adhesively fixing an optical film on a conductive member,
As the monomer unit constituting the acrylic copolymer (A), 15 to 45% by weight of (meth)acrylic acid alkyl ester (a-1) unit having an alkyl group having 1 to 3 carbon atoms and acrylic acid having an alkyl group having 4 to 8 carbon atoms A monomer containing 54.4 to 84.8% by weight of an alkyl ester (a-2) unit and 0.2 to 0.6% by weight of a (meth)acrylic acid hydroxyester (a-3) unit having an alkyl group having 2 to 4 carbon atoms, and containing an acidic group unit and amide group-containing monomer units,
The acrylic copolymer (A) has a weight average molecular weight (Mw) of 1,200,000 to 1,600,000, and a dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is 1.5 to 2.5. . According to claim 1,
The pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive has a storage elastic modulus at 25 ° C. of 0.5 to 1 MPa, and an elastic retention rate represented by the following formula (1) of 60 to 100%.
Elastic retention (%) = G' (80 ° C) / G' (25 ° C) × 100 ... Equation (1)
(However, in Formula (1), G' (80 ° C.) represents the storage modulus at 80 ° C., and G' (25 ° C.) represents the storage elastic modulus at 25 ° C., respectively.)
According to claim 1,
The pressure-sensitive adhesive characterized in that the crosslinking agent (B) is an isocyanate compound.
According to claim 1,
An adhesive characterized by further containing an organic silane compound (C) having an epoxy group or an epoxy cyclohexyl group.
The adhesive sheet for optics provided with the optical film and the adhesive layer formed from the adhesive of any one of Claims 1-4.
A polarizing plate adhesive sheet comprising a polarizing plate and a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive according to any one of claims 1 to 4.
A liquid crystal cell member comprising a conductive member and a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive according to any one of claims 1 to 4.