JP5678531B2 - Adhesive and adhesive film using the same - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive suitably used for adhesion of members constituting a color display device such as a liquid crystal display device, particularly a polarizing plate. More specifically, the present invention relates to a pressure-sensitive adhesive that exhibits excellent adhesive properties after crosslinking treatment, in particular, has excellent removability, and can form an adhesive layer that does not float or peel off by heat treatment and high-humidity treatment.

  Conventionally, when an adhesive film or the like is bonded to an inorganic surface such as glass, ceramics, or metal, phenomena such as peeling off at the edge of the film or floating at the bonding portion due to changes over time are often observed. It is done.

  In order to solve such a phenomenon, in general, an adhesive film with improved adhesive properties is used by increasing the molecular weight of the polymer used in the adhesive film or increasing the crosslinking density of the adhesive layer. I came. However, when such an adhesive film is used, the adhesive force and cohesive force are improved, but under high temperature and high humidity, the adhesive layer cannot follow the shape change caused by the shrinkage and swelling of the base film, and the Problems such as peeling could not be solved.

  Incidentally, some optical members used in liquid crystal display devices are used with a polarizing plate attached to the surface thereof, and a typical example is a liquid crystal cell. With respect to the adhesive used for bonding the polarizing plate and the liquid crystal cell, which are members of the liquid crystal display device, durability that prevents the polarizing plate from peeling or floating even under various environments, and the liquid crystal cell The performance which can prevent the light leak in is required. This light leakage occurs as a result of non-uniform residual stress in the polarizing plate, particularly in a high-temperature and high-humidity environment, when the stress accompanying the dimensional change such as contraction / expansion of the polarizing plate cannot be absorbed by the adhesive layer.

  In order to solve such a problem of light leakage, for example, a technique for imparting stress relaxation properties by appropriately softening the adhesive layer by adding a plasticizer or the like to the adhesive is disclosed (Patent Document 1). reference). However, the addition of a plasticizer causes blisters that contaminate the adherend when the polarizing plate is peeled off, and lowers the cohesive force, so that floating and peeling with time are likely to occur.

  On the other hand, an adhesive formed by blending an acrylic copolymer and an active energy ray-curable compound having an isocyanurate skeleton is disclosed (see Patent Document 2). In this publication, examples are described for polarizing plates, but none of the examples describes the appearance of the coating film. When this inventor evaluated the coating-film external appearance using the adhesive described in the Example of this gazette, the coating-film was whitened and the favorable result was not obtained.

  Moreover, the adhesive which mix | blends an acrylic polymer and an isocyanate compound 5-30 weight part is disclosed (refer patent document 3). However, in this publication, examples are described for polarizing plates, but no description about the appearance of the coating film is made in any of the examples. When this inventor evaluated the coating-film external appearance using the adhesive described in the Example of this gazette, the coating-film was whitened and the favorable result was not obtained.

  Thus, it is thought that various performances that are insufficient with an acrylic polymer alone can be improved by adding various compounds to the acrylic polymer to prepare an adhesive. However, these compounds often have poor compatibility with acrylic polymers, and the addition of a small amount does not significantly impair the transparency of the adhesive layer, but at the addition amount necessary to express the performance improvement effect. The transparency of the adhesive layer is impaired or separated. An adhesive for attaching a polarizing film or the like to glass for a liquid crystal cell is required to have extremely high transparency. And even if it tries to stick a polarizing film etc. to the glass for liquid crystal cells using the adhesive which mixed the compound as mentioned above incompatible, whitening, phase separation, and fluctuation will occur in the adhesion layer. There was a problem.

  In addition, when a polarizing plate is bonded to an optical component such as a liquid crystal cell in a manufacturing process of a liquid crystal display or the like, the polarizing plate is peeled off after a certain period of time has elapsed since the bonding position has shifted. It may be necessary to reuse expensive liquid crystal cells. Therefore, there is a need for a pressure-sensitive adhesive having re-peeling performance that can be peeled relatively easily from a liquid crystal cell even after a certain period of time after being bonded via a pressure-sensitive adhesive applied to a polarizing plate. It was done. This is a property that is contrary to the strong adhesion for imparting durability, and it has been a problem to achieve both. Furthermore, there is a need for a pressure-sensitive adhesive that can be peeled off from an adherend relatively easily even after a certain period of time has elapsed from pasting, and that provides strong adhesion under harsh conditions such as high temperature and high humidity. It was done.

Japanese Patent Laid-Open No. 9-87593 JP 2008-31214 A JP 2010-90354 A

  The present invention expresses excellent adhesive properties when used in an adhesive film, in particular, has excellent removability, can form an adhesive layer that does not float or peel off by heat treatment and high-humidity treatment, such as a liquid crystal display device An object of the present invention is to provide a pressure-sensitive adhesive suitably used for the color display device.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems. That is, 1st invention is an adhesive containing 5-40 weight part of isocyanate compounds (B) with respect to 100 weight part of acrylic polymers (A),
The acrylic polymer (A) is a copolymer having a weight average molecular weight of 500,000 to 2,000,000 obtained by copolymerizing a monomer containing 0.2 to 10% by weight of an amide bond-containing ethylenically unsaturated monomer (a1). Yes,
The isocyanate compound (B) is one or more monofunctional aliphatic alcohols (b2) having an alkyl group having 4 to 25 carbon atoms and one or more in the molecule with respect to 100 moles of isocyanate groups in the trifunctional isocyanate compound (b1). The present invention relates to a pressure-sensitive adhesive characterized by being a compound obtained by reacting 3 to 40 mol of at least one of aliphatic secondary amines (b3) having an alkyl group having 4 to 25 carbon atoms.

  Moreover, 2nd invention is related with the adhesive film characterized by having a base material (C) and the adhesion layer formed from the adhesive of Claim 1.

  The third invention relates to the pressure-sensitive adhesive film according to claim 3, wherein the substrate (C) is an optical member.

  Moreover, 4th invention is related with the adhesive film of Claim 3 whose optical member is a polarizing plate.

  According to the present invention, it exhibits excellent adhesive properties, in particular, excellent removability, can form an adhesive layer that does not float or peel off by heat treatment and high humidity treatment, and is suitable for color display devices such as liquid crystal display devices. It has become possible to provide a pressure-sensitive adhesive to be used.

It is the schematic which looked at the constant load peeling test from the side.

  The pressure-sensitive adhesive of the present invention will be described in detail. The pressure-sensitive adhesive of the present invention is a pressure-sensitive adhesive containing 5 to 40 parts by weight of an isocyanate compound (B) with respect to 100 parts by weight of an acrylic polymer (A), and contains an amide bond-containing ethylenically unsaturated monomer (a1). ) A copolymer having a weight average molecular weight of 500,000 to 2,000,000 obtained by copolymerizing a monomer containing 0.2 to 10% by weight, and the isocyanate compound (B) is an isocyanate group in the trifunctional isocyanate compound (b1). Monofunctional aliphatic alcohol (b2) having an alkyl group having 4 to 25 carbon atoms and an aliphatic secondary amine (b3) having one or more alkyl groups having 4 to 25 carbon atoms in the molecule with respect to 100 moles It is a compound formed by reacting 3 to 40 mol of at least one of them.

In this invention, when manufacturing an adhesive film, an isocyanate compound (B) produces | generates a polymer by the isocyanate groups of an isocyanate compound (B) reacting with the water | moisture content in an adhesion layer as a medium. And it is preferable that the polymer produced | generated from the acrylic polymer (A) and the isocyanate compound (B) does not take a crosslinked structure like a covalent bond. Since the polymer produced from the isocyanate compound (B) exists separately from the acrylic polymer (A), the excellent adhesion of the acrylic polymer (A) and the polymer produced from the isocyanate compound (B) Both characteristics of cohesive strength can be exhibited effectively. On the other hand, weak bonds such as hydrogen bonds and intermolecular forces are preferable because there is room for interaction between polymers without impairing the characteristics of both polymers. And since compatibility of both polymers becomes favorable, adhesiveness with a to-be-adhered body and cohesion force of an adhesion layer can be achieved at a high level.
Here, when the trifunctional isocyanate compound (b1) is used for the isocyanate compound (B), the polymer has a very high cohesive force because (b1) forms a highly three-dimensional structure using moisture as a medium. become. Therefore, the entanglement of the polymer produced from the acrylic polymer (A) and the trifunctional isocyanate compound (b1) is reduced, and both polymers are likely to be incompatible with each other in the adhesive layer. And when both polymers exist incompatible, there exists a possibility that an adhesion layer may become white and transparency may fall. In addition, since the urea bond that tends to impair the flexibility of the adhesive layer is excessively present in the polymer formed from the trifunctional isocyanate compound (b1) having a highly three-dimensional structure, the adhesion between the adhesive layer and the adherend There is a risk of damage. Moreover, the polymer formed from the incompatible trifunctional isocyanate compound (b1) is likely to migrate to the surface of the adhesive layer because of incompatibility. Therefore, the pressure-sensitive adhesive film may float or peel off from the adherend in a high temperature and high humidity environment.
Therefore, in the present invention, a part of the isocyanate group in the trifunctional isocyanate compound (b1) is sealed with a monofunctional aliphatic alcohol (b2) or an aliphatic secondary amine (b3), whereby the isocyanate compound is sealed. By appropriately controlling the three-dimensional structure of the polymer produced from (B), the cohesive force does not become excessive, and appropriate compatibility with the acrylic polymer (A) can be realized. And the adhesiveness of an adhesive film etc. and a to-be-adhered body, and the cohesion force of an adhesion layer are realizable at high level. Examples of the adherend include glass, an acrylic plate, a stainless plate, and a polycarbonate plate.

  In the present invention, the acrylic polymer (A) is a polymer of an ethylenically unsaturated monomer containing a (meth) acrylic acid ester monomer. In the present invention, the (meth) acrylic acid ester monomer means both an acrylic acid ester monomer and a methacrylic acid ester monomer.

  As a monomer used for the polymerization of the acrylic polymer (A), it is important to use 0.2 to 10% by weight of the amide bond-containing ethylenically unsaturated monomer (a1) in the total monomers. The amide bond-containing ethylenically unsaturated monomer (a1) acts as a catalyst in the reaction between isocyanate groups of the isocyanate compound (B) using moisture as a medium, but if the amount used is less than 0.2% by weight, the catalytic effect Is too small, the reaction between the isocyanate compound (B) and moisture hardly occurs, and there is a problem that a large amount of isocyanate groups remain. Furthermore, if the amount used is less than 0.2% by weight, there is a problem that sufficient compatibility with the polymer produced from the isocyanate compound (B) cannot be obtained. If it exceeds 10% by weight, the cohesive force of the acrylic polymer (A) itself is too strong, and there is a problem that sufficient adhesion cannot be obtained.

  In the present invention, the amide bond in the amide bond-containing ethylenically unsaturated monomer may be any one of 0 to 2 hydrogen atoms bonded to the nitrogen atom in the amide bond. Specifically, for example, (meth) acrylamide, N-methylacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-dimethylaminopropyl (meth) acrylamide, diacetone acrylamide (Meth) acrylamide compounds such as N- (hydroxymethyl) acrylamide and N- (butoxymethyl) acrylamide, compounds containing a heterocyclic ring such as N-vinylpyrrolidone, N-vinylcaprolactam and acryloylmorpholine, N -Vinylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide and the like can be mentioned, but are not particularly limited thereto. These may be used alone or in combination of two or more. Among these, (meth) acrylamide is particularly preferable from the viewpoint that an acrylic copolymer having a weight average molecular weight of 500,000 to 2,000,000 can be easily produced.

  In addition to the amide bond-containing ethylenically unsaturated monomer (a1), as long as the compatibility and adhesion between the acrylic polymer (A) and the polymer produced from the isocyanate compound (B) are not impaired, other An ethylenically unsaturated monomer having the following functional group can be used. For example, a carboxyl group-containing ethylenically unsaturated monomer, a hydroxyl group-containing ethylenically unsaturated monomer, an epoxy group-containing ethylenically unsaturated monomer, or an amino group-containing ethylenically unsaturated monomer can be used.

  Examples of carboxyl group-containing ethylenically unsaturated monomers include (meth) acrylic acid, monohydroxyethyl acrylate phthalate, p-carboxybenzyl acrylate, ethylene oxide modified (added moles: 2 to 18) phthalic acid acrylate, phthalic acid mono Hydroxypropyl acrylate, succinic acid monohydroxyethyl acrylate, β-carboxyethyl acrylate, 2- (4-benzoyl-3-hydroxyphenoxy) ethyl acrylate, maleic acid, monoethylmaleic acid, itaconic acid, citraconic acid, fumaric acid, etc. Is mentioned. These may be used alone or in combination of two or more. Among these, (meth) acrylic acid is particularly preferable, and the amount used is preferably 5% by weight or less.

  Examples of the hydroxyl group-containing ethylenically unsaturated monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxy (meth) acrylate. And (meth) acrylic acid hydroxyalkyl esters such as butyl, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. These may be used alone or in combination of two or more. Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable from the viewpoint that an acrylic copolymer having a weight average molecular weight of 500,000 to 2,000,000 can be easily produced. Further, the amount used needs to be an extent that does not impair the flexibility of the acrylic polymer (A) when reacted with the isocyanate compound (B), and is preferably 0.3% by weight or less.

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

  There is no restriction | limiting in particular as an ethylenically unsaturated monomer which does not have a functional group, For example, the C1-C20 (meth) acrylic-acid alkylester monomer whose carbon number of the ester part can be mentioned. Here, as an example of the (meth) acrylic acid alkyl ester monomer having 1 to 20 carbon atoms of the alkyl group in the ester portion, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate , Dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more. Among these compounds, among these compounds, butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are easy to obtain good adhesive performance, and an acrylic copolymer having a weight average molecular weight of 500,000 to 1,500,000. Is preferable because it can be easily manufactured.

  Examples of other ethylenically unsaturated monomers include vinyl acetate, vinyl crotonate, styrene, acrylonitrile and the like.

  The acrylic polymer (A) can be obtained by radical polymerization of an ethylenically unsaturated monomer using a radical polymerization initiator. The radical polymerization can be performed by a known polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization or the like, but solution polymerization is preferable from the viewpoint of molecular weight control. The solution polymerization is preferably performed in the presence of a solvent such as acetone, methyl acetate, ethyl acetate, toluene, xylene, anisole, methyl ethyl ketone, cyclohexanone, and the like. The radical polymerization temperature is preferably in the range of 60 to 120 ° C., and the polymerization time is preferably 5 to 12 hours.

  The acrylic polymer (A) in the present invention preferably has a weight average molecular weight of 500,000 to 2,000,000, more preferably 500,000 to 1,500,000. When the weight average molecular weight is less than 500,000, adhesion to the adherend and durability under a high temperature and high humidity environment are insufficient, and there is a risk that the adherend is lifted off or peeled off. On the other hand, when the weight average molecular weight exceeds 2 million, the fluidity of the pressure-sensitive adhesive containing the acrylic copolymer (A) is lowered, and it may be difficult to produce a pressure-sensitive adhesive film. In addition, the said weight average molecular weight is the value of polystyrene conversion measured by the gel permeation chromatography (GPC) method. In the pressure-sensitive adhesive of the present invention, one type of acrylic copolymer (A) may be used, or two or more types may be used in combination.

  Next, the isocyanate compound (B) will be described. By reacting the monofunctional alcohol (b2) and / or the secondary amine (b3) with 3 to 40 mol of the isocyanate compound (B) with respect to 100 mol of the isocyanate group in the trifunctional isocyanate compound (b1), It is characterized by being a compound in which a urethane bond and / or a urea bond is introduced. A urethane bond is introduced by the monofunctional alcohol (b2), and a urea bond is introduced by the secondary amine (b3). Moreover, a polymer is produced | generated when the isocyanate groups of an isocyanate compound (B) react using the water | moisture content in an adhesion layer as a medium.

  In the present invention, the trifunctional isocyanate compound (b1) is a burette of various isocyanate monomers having two isocyanate groups, such as aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, and alicyclic polyisocyanate, Examples include nurate bodies and adduct bodies.

  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-condensation product having a burette bond formed by self-condensation of the isocyanate monomer. For example, a buret body of hexamethylene diisocyanate (Sumijour N-75, manufactured by Sumika Bayer Urethane Co., Ltd .; Duranate 24A-90CX, manufactured by Asahi Kasei).

  The nurate refers to a trimer of the above-mentioned isocyanate monomer. For example, hexamethylene diisocyanate trimer (Sumijour N-3300, manufactured by Sumika Bayer Urethane Co., Ltd .; Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd .; Aquanate 100, manufactured by Nippon Polyurethane Co., Ltd .; Aquanate 110, manufactured by Nippon Polyurethane Industry Co., Ltd .; Duranate TPA100, manufactured by Asahi Kasei Co., Ltd. Sumika Bayer Urethane Co., Ltd.), tolylene diisocyanate trimer (Coronate 2030, manufactured by Nippon Polyurethane Co., Ltd.), and the like.

  An adduct is a bifunctional or higher functional isocyanate compound obtained by reacting the above isocyanate monomer with a bifunctional or higher functional low-molecular hydrogen-containing compound. For example, a compound obtained by reacting trimethylolpropane and hexamethylene diisocyanate. (Coronate HL, manufactured by Nippon Polyurethane Co., Ltd .; Sumidur HT, manufactured by Sumika Bayer Urethane Co., Ltd .; Takenate D-160N, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), a compound obtained by reacting trimethylolpropane and tolylene diisocyanate (Coronate L, Nippon Polyurethane Co., Ltd .; Sumidur L-75, Sumika Bayer Urethane Co., Ltd .; Takenate D-102, Mitsui Chemicals Polyurethane Co., Ltd., a compound obtained by reacting trimethylolpropane and xylylene diisocyanate (Takenate D-110) , Manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), a compound obtained by reacting trimethylolpropane and isophorone diisocyanate (Takenate D-140N, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd .; Maitec NY215A, manufactured by Mitsubishi Chemical Corporation), 1,6-hexanediol and Examples thereof include a compound obtained by reacting with hexamethylene diisocyanate (Duranate D-201, manufactured by Asahi Kasei).

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′-di- Methylol heptane, 2-methyl-1,8-octanediol, 3,3′-dimethylol heptane, 2-butyl-2-ethyl-1,3-propanediol, polyoxyethylene glycol (added mole number of 10 or less), Polyoxypropylene glycol (added mole number 10 or less), 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol , Butylethylpentanediol, 2-ethyl-1,3-hexane Ol, 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 bifunctional or more low molecular active hydrogen-containing compounds may be used alone or in combination of two or more.

  Among the trifunctional isocyanate compounds (b1), in consideration of adhesion and adhesion durability, a trimethylolpropane adduct body of tolylene diisocyanate, a trimethylolpropane adduct body of hexamethylene diisocyanate, a trimethylolpropane adduct body of isophorone diisocyanate, A trimethylolpropane adduct of xylylene diisocyanate, an isocyanurate of tolylene diisocyanate, an isocyanurate of hexamethylene diisocyanate, and an isocyanurate of isophorone diisocyanate are preferred. These trifunctional isocyanate compounds may be used alone or in combination of two or more.

  The isocyanate compound (B) is obtained by reacting 3 to 40 mol of the monofunctional alcohol (b2) and / or the secondary amine (b3) with respect to 100 mol of the isocyanate group in the trifunctional isocyanate compound (b1). And a compound having a urethane bond or a urea bond. If the monofunctional alcohol (b2) and / or the secondary amine (b3) is less than 3 mol, the compatibility with the acrylic polymer (A) may be poor and whitening may occur, and the monofunctional alcohol (b2) and If the secondary amine (b3) exceeds 40 moles, the adhesion durability decreases. In particular, considering the adhesion durability and the compatibility with the acrylic polymer (A), the monofunctional alcohol (b2) and / or the secondary amine (b3) is more preferably 5 to 35 mol.

  In consideration of compatibility with the acrylic polymer (A) in particular, monofunctional aliphatic alcohols having an alkyl group having 4 to 25 carbon atoms are preferred, and the molecular structure of the alcohol is either a linear structure or a branched structure. But it ’s okay. If the number of carbon atoms is in the range of 4 to 25, the resistance to floating and peeling at high temperature and high humidity can be further improved.

  Examples of the monofunctional alcohol (b2) used in the present invention include butyl alcohol (carbon number 4), pentyl alcohol (carbon number 5), hexyl alcohol (carbon number 6), heptyl alcohol (carbon number 7), and octyl. Alcohol (carbon number 8), 2-ethylhexyl alcohol (carbon number 8), nonyl alcohol (carbon number 9), decyl alcohol (carbon number 10), undecyl alcohol (carbon number 11), dodecyl alcohol (carbon number 12), Tridecyl alcohol (carbon number 13), tetradecyl alcohol (carbon number 14), pentadecyl alcohol (carbon number 15), hexadecyl alcohol (carbon number 16), heptadecyl alcohol (carbon number 17), octadecyl alcohol (carbon number) 18), eicosane alcohol (carbon number 20), pentacosa Like alcohol (25 carbon atoms). Among these, 2-ethylhexyl alcohol, dodecyl alcohol, and hexadecyl alcohol are particularly preferable. These monofunctional alcohols (b2) may be used alone or in combination of two or more.

  Considering the compatibility with the acrylic polymer (A), the secondary amine (b3) is preferably an aliphatic secondary amine having 4 to 25 alkyl groups. The structures of the two alkyl groups of the amine may be the same or different. If the number of carbon atoms is in the range of 4 to 25, the resistance to floating and peeling at high temperature and high humidity can be further improved.

  Examples of the secondary amine (b3) used in the present invention include dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, di (2-ethylhexyl) amine, dinonylamine, didecylamine, diundecylamine, Didodecylamine, ditridecylamine, ditetradecylamine, dipentadecylamine, dihexadecylamine, diheptadecylamine, dioctadecylamine, dinonadecylamine, dieicosylamine, dipentacosylamine, N-methylbutylamine N-methylhexylamine, N-methylhexadecylamine, N-butylhexadecylamine and the like.

  In the present invention, when the isocyanate compound (B) is obtained, the monofunctional alcohol (b2) and the secondary amine (b3) can be used in combination. When synthesizing the isocyanate compound (B), both the urethane bond and the urea bond are introduced into the skeleton of the isocyanate compound (B) by using the monofunctional alcohol (b2) and the secondary amine (b3) in combination. be able to.

  As a manufacturing method of an isocyanate compound (B), it can obtain by heating a trifunctional isocyanate compound (b1), a monofunctional alcohol (b2), and / or a secondary amine (b3) under nitrogen sealing. The reaction temperature is preferably in the range of 60 to 100 ° C., and the reaction time is preferably 2 to 5 hours. When the reaction temperature is lower than 60 ° C. or the reaction time is shorter than 2 hours, the reaction between the trifunctional isocyanate compound (b1) and the monofunctional alcohol (b2) or the secondary amine (b3) is not completed. There is a case. On the other hand, if the reaction temperature is higher than 100 ° C. or the reaction time is longer than 5 hours, side reactions such as allophanate reaction and burette reaction may occur, and the target isocyanate compound (B) may not be obtained.

  It is important that the pressure-sensitive adhesive of the present invention contains 5 to 40 parts by weight of the isocyanate compound (B) with respect to 100 parts by weight of the acrylic polymer (A), and more preferably 7 to 35 parts by weight. preferable. When the amount of the isocyanate compound (B) used exceeds 40 parts by weight, the flexibility of the pressure-sensitive adhesive is impaired, and the adhesion of the resulting pressure-sensitive adhesive layer to the adherend tends to decrease, which may cause a problem in durability. is there. Further, the compatibility with the acrylic polymer (A) is deteriorated, and the adhesive layer may be whitened. If the amount is less than 5 parts by weight, sufficient cohesive force cannot be obtained, which may cause problems in heat resistance and moist heat resistance.

  If the adhesive of this invention is a grade which does not impair the characteristic of this invention, a crosslinking agent can be used. An epoxy compound, an amine compound, an aziridine compound, a carbodiimide compound, an oxazoline compound, a melamine compound, a metal chelate compound and the like having two or more functional groups in the molecule are preferable, and an aziridine compound or a metal chelate compound is particularly preferable.

  Among the crosslinking agents, as the epoxy compound, 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, diglycidylaniline, N, N, N ', N'-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N'-diglycidyl Aminomethyl) cyclohexane and the like.

Among the cross-linking agents, the amine compound is preferably a polyamine having two or more primary amino groups, and a polyamine having two or more primary amino groups not directly bonded to the aromatic ring from the viewpoint of excellent curing speed. An aliphatic polyamine (which may contain an aromatic ring in its skeleton) is preferable. Examples of the aliphatic polyamine include 2,5-dimethyl-2,5-hexamethylenediamine, mensendiamine, Bis (2-amino-2-methylpropyl) piperazine, polypropylene glycol (propylene skeleton diamine, propylene skeleton triamine), ethylene diamine, propylene diamine, butylenediamine, diethylenetriamine Triethylenetetramine, tetraethylenepentami , Pentaethylenehexamine, hexamethylenediamine, trimethylhexamethylenediamine, N-aminoethylpiperazine, 1,2-diaminopropane, iminobispropylamine, methyliminobispropylamine, H ₂ N (CH ₂ CH ₂ O) ₂ Polyether skeleton diamine, 1,5-diamino-2-methylpentane, metaxylylenediamine (MXDA), polyamide, in which a methylene group is bonded to amine nitrogen such as (CH ₂ ) ₂ NH ₂ (ethylene glycol skeleton diamine) Examples include amines, isophorone diamine, 1,3-bisaminomethylcyclohexane, 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3,3,5-trimethyl-cyclohexylamine, dimethyleneamine having a norbornane skeleton. Can do. Among these, since the curing rate is particularly high, 1,3-bisaminomethylcyclohexane, dimethyleneamine having a norbornane skeleton, metaxylylenediamine, H ₂ N (CH ₂ CH ₂ O)) ₂ (CH ₂ ) ₂ NH ₂ (ethylene glycol skeleton diamine), propylene skeleton diamine, propylene skeleton triamine, and polyamidoamine are usefully used.

  In addition, ketimine, which is a reaction product of these polyamines and ketones, is also included in the amino compound, and acetophenone or propiophenone and 1,3-bisaminomethyl are used from the viewpoints of stability, reactivity adjustment and overcoatability. Obtained from cyclohexane; obtained from acetophenone or propiophenone and dimethyleneamine (NBDA) of norbornane skeleton; obtained from acetophenone or propiophenone and metaxylylenediamine; and acetophenone or propiophenone , Jeffamine EDR148 which is a diamine having an ethylene glycol skeleton or propylene skeleton, Jeffamine D230, Jeffamine D400 or the like, or Jeffamine T403 which is a propylene skeleton triamine or the like. Things like can also be used.

  Among the crosslinking agents, examples of the aziridine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxite), N, N′-toluene-2,4-bis (1-aziridinecarboxyl). Site), bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxite), trimethylol Propane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, Trimethylolpropane tris [3- (1-aziridinyl) propionate], trimethylolpropane tris [3- (1-aziridinini L) butyrate], trimethylolpropane tris [3- (1- (2-methyl) aziridinyl) propionate], trimethylolpropane tris [3- (1-aziridinyl) -2-methylpropionate], 2,2 ′ -Bishydroxymethylbutanol tris [3- (1-aziridinyl) propionate], pentaerythritol tetra [3- (1-aziridinyl) propionate], diphenylmethane-4,4-bis-N, N′-ethyleneurea, 1,6 -Hexamethylenebis-N, N'-ethyleneurea, 2,4,6- (triethyleneimino) -Syn-triazine, bis [1- (2-ethyl) aziridinyl] benzene-1,3-carboxylic acid amide, etc. Is mentioned.

  Among the crosslinking agents, as the carbodiimide compound, a compound having two or more carbodiimide groups in the molecule is preferably used, and a known polycarbodiimide can be used. Moreover, the high molecular weight polycarbodiimide produced | generated by carrying out the decarboxylation condensation reaction of diisocyanate in presence of a carbodiimidization catalyst can also be used.

Examples of the high molecular weight polycarbodiimide include those obtained by subjecting the following diisocyanates to a decarboxylation condensation reaction.
Examples of the diisocyanate include 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, and 4,4′-diphenyl ether. Diisocyanate, 3,3′-dimethyl-4,4′-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4 One of '-dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, or a mixture thereof can be used.

  Examples of the carbodiimidization catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, 1- Phosphorene oxides such as ethyl-2-phospholene-1-oxide or their 3-phospholene isomers can be utilized.

  Among the crosslinking agents, as the oxazoline compound, a compound having two or more oxazoline groups in the molecule is preferably used. For example, 2′-methylenebis (2-oxazoline), 2,2′-ethylenebis (2-oxazoline) 2,2′-ethylenebis (4-methyl-2-oxazoline), 2,2′-propylenebis (2-oxazoline), 2,2′-tetramethylenebis (2-oxazoline), 2,2′- Hexamethylene bis (2-oxazoline), 2,2′-octamethylene bis (2-oxazoline), 2,2′-p-phenylene bis (2-oxazoline), 2,2′-p-phenylene bis (4 4'-dimethyl-2-oxazoline), 2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2'-p-phenylenebis (4- Phenyl-2-oxazoline), 2,2′-m-phenylenebis (2-oxazoline), 2,2′-m-phenylenebis (4-methyl-2-oxazoline), 2,2′-m-phenylenebis (4,4′-dimethyl-2-oxazoline), 2,2′-m-phenylenebis (4-phenylenebis-2-oxazoline), 2,2′-o-phenylenebis (2-oxazoline), 2, 2'-o-phenylenebis (4-methyl-2-oxazoline), 2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'- Bis (4-ethyl-2-oxazoline), 2,2′-bis (4-phenyl-2-oxazoline) and the like can be mentioned. Alternatively, ethenyl monomers such as 2-isopropenyl-2-oxazoline and 2-isopropenyl-4,4-dimethyl-2-oxazoline, and other monomers that can be copolymerized with these ethenyl monomers. It may be a copolymer with a monomer.

  Among the crosslinking agents, the melamine compound is a compound having a triazine ring in the molecule, and examples thereof include melamine, benzoguanamine, cyclohexanecarboguanamine, methylguanamine, vinylguanamine, hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine and the like. . These low-condensates, alkyl etherified formaldehyde resins and aminoplast resins may also be used.

  Among the cross-linking agents, examples of metal chelate compounds include, for example, polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium in acetylacetone and ethyl acetoacetate. Examples include a coordinated compound.

  These crosslinking agents may be used alone or in combination.

  The pressure-sensitive adhesive of the present invention preferably contains a silane coupling agent. By using a silane coupling agent, the adhesiveness between the adhesive layer and the adherend is improved, and the heat resistance and heat-and-moisture resistance can be further improved. Moreover, the side reaction with water and an isocyanate compound (B) can be inhibited, and the deactivation of the isocyanate compound (B) by water can be prevented. The amount of the silane coupling agent used is preferably in the range of 0.01 to 1 part by weight, particularly preferably in the range of 0.05 to 0.5 part by weight, with respect to 100 parts by weight of the acrylic polymer (A).

The silane coupling agent used in the present invention is not particularly limited. For example, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyl Alkoxy having (meth) acryloxy groups such as tripropoxysilane, 3- (meth) acryloxypropyltributoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane Silane compounds;
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 include triethoxysilane, hexamethyldisilazane, and a silicone resin having an alkoxysilyl group in the molecule (X-41-1056, manufactured by Shin-Etsu Chemical Co., Ltd., X-41-1810, manufactured by Shin-Etsu Chemical Co., Ltd.).

  The pressure-sensitive adhesive of the present invention includes various resins, coupling agents, oils, softeners, dyes, pigments, antioxidants, ultraviolet absorbers, weather stabilizers, tackifiers and the like as long as the effects of the present invention are not impaired. Plasticizers, fillers, anti-aging agents, etc. may be blended.

In the present invention, the pressure-sensitive adhesive film has a pressure-sensitive adhesive layer formed on the base material from the pressure-sensitive adhesive of the present invention.
The pressure-sensitive adhesive film can be produced, for example, by applying a pressure-sensitive adhesive on a substrate and drying it. The adhesive layer should just be provided in the at least one surface of the base material.

  When applying the adhesive, an appropriate 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; dichloromethane , Halogenated hydrocarbon solvents such as chloroform; ether solvents such as diethyl ether, methoxytoluene, dioxane, and other organic solvents such as hydrocarbon solvents can be added to adjust the viscosity and pressure-sensitive adhesive The viscosity can also be reduced by heating. However, since water, alcohol, etc. may cause reaction inhibition with an acrylic polymer (A) and an isocyanate compound (B), attention is required.

  Examples of the substrate include cellophane, plastic sheet, rubber, foam, cloth, rubber cloth, resin-impregnated cloth, glass plate, wood and the like, and may be plate-like or film-like. Among these, when using for a liquid crystal display device, a base material (C) has a preferable film. Furthermore, the base material can be used alone, or a base material in a multilayer state formed by laminating a plurality of base materials can be used. Furthermore, what carried out the peeling process of the surface of a base material (henceforth a peeling sheet) can also be used.

  The plastic sheet is also called a plastic film. Polyvinyl alcohol film, triacetyl cellulose film, polypropylene, polyethylene, polycycloolefin, polyolefin resin film such as ethylene-vinyl acetate copolymer, polyethylene terephthalate, polybutylene terephthalate, polyethylene Polyester resin film such as naphthalate, polycarbonate resin film, polynorbornene resin film, polyarylate resin film, acrylic resin film, polyphenylene sulfide resin film, polystyrene resin film, vinyl resin Film, polyamide resin film, polyimide resin film, epoxy resin film, etc. It is.

  In the present invention, the method of applying the adhesive is not particularly limited, and may be a Mayer bar, applicator, brush, spray, roller, gravure coater, die coater, lip coater, comma coater, knife coater, reverse coater, spin coater, etc. 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. As drying conditions, although depending on the cured form of the pressure-sensitive adhesive, the film thickness, and the selected solvent, heating with hot air at about 60 to 180 ° C. is usually sufficient.

  The pressure-sensitive adhesive film of the present invention can be obtained by: (a) applying a pressure-sensitive adhesive to the release-treated surface of the release-treated sheet, drying it, and laminating a sheet-like optical member on the surface of the adhesive layer; It can be obtained by applying a pressure-sensitive adhesive to the optical member, drying it, and laminating the release-treated surface of the release-treated sheet on the surface of the adhesive layer.

  The thickness of the adhesive layer is preferably 0.1 to 200 μm, and more preferably 1 to 100 μm. If it is less than 0.1 μm, sufficient adhesive strength may not be obtained, and if it exceeds 200 μm, characteristics such as adhesive strength are often not improved further.

  Furthermore, the adhesive film of the present invention preferably has an adhesive strength of 2 to 15 N / 25 mm after 1 day at 23 ° C. after being bonded to alkali-free glass. When the adhesive strength is less than 2 N / 25 mm, the adhesive strength is insufficient as an adhesive, and there is a risk of floating or peeling. When the adhesive strength is 2 N / 25 mm or more, the adhesive strength is sufficient as an adhesive, and it can be sufficiently fixed to an adherend. Moreover, when this adhesive force is larger than 15 N / 25 mm, there exists a possibility of destroying a to-be-adhered body when it peels again after bonding an adhesive film to an to-be-adhered body.

In the present invention, the gel fraction of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film is preferably 50 to 100% by weight, and particularly preferably 70 to 100% by weight. If the gel fraction is less than 50% by weight, sufficient cohesive force may not be obtained. In addition, the gel fraction as used in the field of this invention is represented by following formula (2).
Formula (2) Gel fraction (% by weight) = (M2 / M1) × 100
M1: Weight of adhesive layer before extraction with ethyl acetate solvent
M2: Weight of adhesive layer after extraction and drying with ethyl acetate solvent

  The pressure-sensitive adhesive of the present invention can be suitably used for laminating optical members. That is, in the pressure-sensitive adhesive film of the present invention, an optical member can be preferably used as a substrate. Specific examples of the optical member include a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, and a brightness enhancement film. A release sheet can be laminated on the other surface of the adhesive layer.

  By peeling off the release sheet covering the surface of the pressure-sensitive adhesive layer from the pressure-sensitive adhesive film thus obtained, for example, by sticking the pressure-sensitive adhesive layer to a glass member for a liquid crystal cell, “sheet-like optical member / pressure-sensitive adhesive layer / liquid crystal A liquid crystal cell member having a configuration of “cell glass member” can be obtained. In the present invention, when the optical member is a polarizing plate, it is particularly useful, and an adhesive film that does not float or peel off can be obtained by heat treatment and high-humidity treatment.

  As described above, the polarizing plate may be composed of a polarizing film alone, but a polarizing film and a viewing angle widening film are preferably integrated. In this case, the thickness of the adhesive layer is usually about 5 to 100 μm, preferably 10 to 50 μm.

  The pressure-sensitive adhesive of the present invention is suitable as a pressure-sensitive adhesive for optical members, as well as general labels and seals, paints, elastic wall materials, waterproof coating materials, flooring materials, tackifiers, pressure-sensitive adhesives, and pressure-sensitive adhesives for laminated structures. Agent, sealing agent, molding material, coating agent for surface modification, binder (magnetic recording medium, ink binder, casting binder, fired brick binder, graft material, microcapsule, glass fiber sizing, etc.), urethane foam (rigid, 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 resistance agent for artificial marble, resin for ink, film (laminate adhesive, protective film, etc.), for laminated glass Fat, 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.

  Specific examples of the present invention will be described below together with comparative examples, but the present invention is not limited to the following examples. In the following examples and comparative examples, “part” and “%” represent “part by weight” and “% by weight”, respectively.

[Synthesis of acrylic polymer]
(Synthesis Example 1-1)
91.5 parts of butyl acrylate, 8 parts of acrylamide, 0.5 part of acrylic acid, 90 parts of ethyl acetate are added to the polymerization tank of the polymerization reactor equipped with a polymerization tank, a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube. Prepared. This polymerization tank was heated to 80 ° C., 0.02 part of 2,2′-azobisisobutyronitrile was added and reacted for 2 hours. Further, 0.02 part of 2,2′-azobisisobutyronitrile was added and reacted for 5 hours. After completion of the reaction, the polymerization tank was cooled and 110 parts of ethyl acetate was added to obtain an acrylic copolymer solution.

(Synthesis Example 1-2)
In a polymerization tank of a polymerization reactor equipped with a polymerization tank, a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, 94.5 parts of butyl acrylate, 5 parts of acrylamide, 0.5 part of acrylic acid, 40 parts of ethyl acetate, 60 parts of methyl acetate was charged. This polymerization tank was heated to 70 ° C., 0.02 part of 2,2′-azobisisobutyronitrile was added and reacted for 2 hours. Further, 0.02 part of 2,2′-azobisisobutyronitrile was added and reacted for 5 hours. After completion of the reaction, the polymerization tank was cooled and 100 parts of ethyl acetate was added to obtain an acrylic copolymer solution.

(Synthesis Examples 1-3 to 1-10)
Various raw materials were charged according to the weight ratios in Table 1, and an acrylic copolymer was synthesized in the same manner as in Synthesis Example 1.

  About the acrylic polymer solution obtained by the synthesis examples 1-1 to 1-10, the appearance of the solution and the weight average molecular weight (Mw) were determined according to the following method. The results are shown in Table 1.

<Appearance of solution>
The appearance of each resin solution was visually evaluated.

<Measurement of weight average molecular weight (Mw)>
For measurement of Mw and Mn, GPC (gel permeation chromatography) “HPC-8020” manufactured by Tosoh Corporation was used. 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.

[Synthesis of Isocyanate Compound (B)]
(Synthesis Example 2-1)
In a polymerization tank of a polymerization reactor equipped with a polymerization tank, a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, coronate L (TMI (tolylene diisocyanate) TMP (trimethylolpropane) adduct, NCO value = 13. 4, nonvolatile content = 75%, manufactured by Nippon Polyurethane Industry Co., Ltd.), 50 parts, 5 parts of 2-ethylhexylamine, and 50 parts of toluene were charged. The polymerization tank was heated to 80 ° C. and further reacted for 3 hours. The NCO value of the reaction solution was measured, and the reaction was completed after confirming the NCO value. This isocyanate compound solution was a pale yellow transparent viscous liquid. The results are shown in Table 2.

(Synthesis Examples 2-2 to 2-17)
Various raw materials were charged according to the weight ratios in Table 2, and an isocyanate compound (B) was synthesized in the same manner as in Synthesis Example 2-1. The results are shown in Table 2.

  In addition, the NCO value of the isocyanate compound (B) obtained in Synthesis Examples 2-1 to 2-17 was determined by the method shown below.

[NCO value of isocyanate compound (B) and modification rate]
Precisely weigh the sample in a stoppered Erlenmeyer flask and add 25 ml of chlorobenzene and 10 ml of a mixture of di-n-butylamine / orthodichlorobenzene (weight ratio: di-n-butylamine / orthodichlorobenzene = 1 / 24.8). Dissolve. To this, 80 g of methanol and bromophenol blue reagent were added as indicators and titrated with a 0.1N alcoholic hydrochloric acid solution. Titration was continued until the solution was yellowish green and held for 30 seconds. The NCO value was determined by the following formula.

NCO value (%) = [0.42 × (BC) × F] / W
However, W: Sample collection amount (g)
B: Consumption of 0.1N alcoholic hydrochloric acid solution required for sample titration (ml)
C: Consumption of 0.1N alcoholic hydrochloric acid solution required for titration of blank test (ml)
F: Potency of 0.1N alcoholic hydrochloric acid solution

Example 1
15 parts of the isocyanate compound of Synthesis Example 2-1 (in terms of solid content) is blended with 100 parts of the acrylic polymer of Synthesis Example 1-1 (in terms of solid content), and ethyl acetate is added as a solvent to reduce the nonvolatile content to 25%. To obtain an adhesive.

  The pressure-sensitive adhesive was applied on a release layer of a release sheet made of polyethylene terephthalate having a thickness of 38 μm and dried to a thickness of 25 μm, and then dried at 100 ° C. for 2 minutes for adhesion. A layer was formed. Next, one surface of a polarizing film having a multilayer structure in which both surfaces of a polyvinyl alcohol (PVA) polarizer are sandwiched between triacetyl cellulose-based protective films (hereinafter referred to as “TAC film”) is bonded to this adhesive layer. An adhesive film having a configuration of “/ adhesive layer / TAC film / PVA / TAC film” was obtained. Subsequently, the obtained adhesive film was aged for one week under the conditions of a temperature of 35 ° C. and a relative humidity of 55%, to obtain an adhesive film in which the adhesive layer was covered with a release film.

(Examples 2 to 21, Comparative Examples 1 to 8)
According to the weight ratios in Table 3 and Table 4, pressure-sensitive adhesives were obtained in the same manner as in Example 1. Further, an adhesive film in which the adhesive layer was coated with a release film was obtained in the same manner as in Example 1.

  The adhesive films obtained in Examples 1 to 21 and Comparative Examples 1 to 8 were evaluated by the following methods. The results are shown in Table 5.

(1) Adhesive strength The adhesive film is cut to a size of 25 mm wide and 100 mm long, the release sheet is peeled off (thickness of adhesive layer is 25 μm), and a laminator is used for alkali-free glass [Corning “1737”]. Stuck. Subsequently, it was kept in an autoclave at 50 ° C. and 5 atm for 20 minutes and adhered to a glass plate. After that, it was allowed to stand for 1 day in an environment of 23 ° C. and a relative humidity of 50%. Using a tensile tester, the adhesive strength was measured under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 °.

(2) Coating film appearance The appearance of the adhesive layer was visually evaluated. The appearance of the adhesive layer was evaluated based on the following three-stage evaluation criteria.
○: “The coating is transparent and has no practical problems”
Δ: “The coating film is slightly whitened and has practical problems”
×: “The entire surface of the coating is whitened and cannot be used practically”

(3) Heat resistance and heat-and-moisture resistance The adhesive film was cut into 160 mm width and 120 mm length, the release sheet was peeled off, and it was attached to non-alkali glass using a laminator. Subsequently, the glass plate to which the adhesive film was attached was held in an autoclave at 50 ° C. and 5 atm for 20 minutes to adhere to the glass plate to obtain a laminate of the adhesive film and the glass plate.

As evaluation of heat resistance, foaming and floating peeling after the laminate was left at 85 ° C. for 500 hours were visually observed. Further, as an evaluation of the heat and moisture resistance, the laminate was left to stand for 500 hours at 60 ° C. and a relative humidity of 95%, and the foaming and floating peeling were visually observed. About heat resistance and wet heat resistance, it evaluated based on the following four-step evaluation criteria.
A: “No foaming or floating peeling is observed, and there is no problem in practical use”
○: “Slight foaming and floating peeling are observed, but there is no practical problem”
Δ: “Severe foaming and floating peeling are observed in several places, and there are practical problems”
×: “There is foaming and floating peeling on the entire surface, impractical”

(4) Light leakage (white spots)
The adhesive film was cut into 160 mm width and 120 mm length, and the release sheet was peeled off, and pasted using a laminator so that the absorption axes of the polarizing plates of the two adhesive films were orthogonal to both surfaces of the alkali-free glass. Subsequently, the glass plate to which the adhesive film was attached was held in an autoclave at 50 ° C. and 5 atm for 20 minutes to adhere to the glass plate to obtain a laminate of the adhesive film and the glass plate.
After this laminate was left at 85 ° C. for 500 hours, light leakage (white spots) when light was transmitted through the polarizing plate was visually observed. The light leakage was evaluated based on the following four evaluation criteria.
A: “No whitening is observed and there is no practical problem”
○: “Slight whitening is recognized, but there is no practical problem”
Δ: “Severe white spots are observed in several places, and there are practical problems”
×: “There is whitening on the entire surface and is not practical”

(5) Removability (reworkability)
The pressure-sensitive adhesive film was cut to a size of 25 mm wide and 100 mm long, the release sheet was peeled off, and it was attached to non-alkali glass using a laminator. Subsequently, it was held in an autoclave at 50 ° C. and 5 atm for 20 minutes to be in close contact with the glass plate. After leaving this test piece at 85 ° C. for 3 hours, a 180 ° peel test is performed in a 23 ° C. and 50% relative humidity environment using a tensile tester to peel it off at a rate of 300 mm / min in the direction of 180 °. Then, the fogging of the glass surface after peeling was visually observed and evaluated based on the following three-stage evaluation criteria.
○: “No glue residue or cloudiness is observed and there is no practical problem”
Δ: “Slight adhesive residue, cloudiness is observed, and there are practical problems”
X: “Transfer of the adhesive was recognized over the entire surface and was not practical”

(6) Constant load peelability The pressure-sensitive adhesive film was cut to a size of 25 mm width and 100 mm length, the release sheet was peeled off, and only a size of 25 mm width and 80 mm length was attached to non-alkali glass using a laminator. Subsequently, the film was kept in an autoclave at 50 ° C. and 5 atm for 20 minutes to be in close contact with the glass plate, and then left for 24 hours in an environment of 23 ° C. and 50% relative humidity. After leaving this test piece for 30 minutes in an environment of 80 ° C., as shown in FIG. 1, a load of 100 g was applied in the direction of 90 ° with respect to the glass surface, and the test piece was further left for 24 hours. The magnitude | size of the peeling location of a test piece was measured after the test, and it evaluated based on the following three-stage evaluation criteria. In addition, the adhesiveness of the adhesive film under conditions severer than a heat resistance test can be evaluated by a constant load peelability test.
○: “The peeled portion is 25 mm ² or less, and there is no practical problem”
Δ: “Peeling location is 25 mm ² to 125 mm ^2, which is a practical problem”
×: “Peeled part is 125 mm ² or more, impractical”

  As shown in Examples 1 to 21 from the results in Table 5, the pressure-sensitive adhesive of the present invention is excellent in coating film appearance, heat resistance, moist heat resistance, re-peelability, light leakage, and constant load peelability. I understand. On the other hand, in Comparative Examples 1-8, since any item is defective, it turns out that there is a problem in practical use or it is impractical.

  The pressure-sensitive adhesive of the present invention has excellent properties such as heat resistance, moist heat resistance, optical properties, and removability required for optical films. In particular, in the use of optical films, light leakage, which is an optical property, is regarded as important, and the required performance has become increasingly severe with the recent increase in size of displays. Therefore, the pressure-sensitive adhesive of the present invention is considered to be more useful because it can exhibit the pressure-sensitive adhesive properties that have been difficult so far as described above.

A: Alkali-free glass B: Adhesive layer C: “TAC / PVA / TAC” laminated film

Claims (4)

An adhesive containing 5 to 40 parts by weight of the isocyanate compound (B) with respect to 100 parts by weight of the acrylic polymer (A),
The acrylic polymer (A) is a copolymer having a weight average molecular weight of 500,000 to 2,000,000 obtained by copolymerizing a monomer containing 0.2 to 10% by weight of an amide bond-containing ethylenically unsaturated monomer (a1). Yes,
The isocyanate compound (B) is one or more monofunctional aliphatic alcohols (b2) having an alkyl group having 4 to 25 carbon atoms and one or more in the molecule with respect to 100 moles of isocyanate groups in the trifunctional isocyanate compound (b1). A pressure-sensitive adhesive comprising a compound obtained by reacting 3 to 40 mol of at least one of aliphatic secondary amines (b3) having an alkyl group having 4 to 25 carbon atoms.   A pressure-sensitive adhesive film comprising a substrate (C) and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive according to claim 1. The pressure-sensitive adhesive film according to claim 2 , wherein the substrate (C) is an optical member. The pressure-sensitive adhesive film according to claim 3, wherein the optical member is a polarizing plate.

Images