JP2922283B2 - Acrylic copolymer for thermosetting pressure-sensitive adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermosetting pressure-sensitive adhesive for forming a pressure-sensitive adhesive layer having both tackiness before thermosetting and strong adhesive strength after thermosetting. More specifically, the present invention relates to an acrylic copolymer used for a thermosetting pressure-sensitive adhesive composition comprising an acrylic copolymer, an epoxy resin, and an epoxy resin curing agent. Acrylic copolymer having a specific molecular weight obtained by copolymerizing a specific amount of an epoxy group-containing monomer and a specific amount of a hydroxyl group-containing monomer, and according to the required physical properties as a thermosetting pressure-sensitive adhesive. Thermosetting pressure-sensitive adhesive composition that always shows excellent compatibility even when mixed with epoxy resin at various ratios, has excellent tackiness and initial adhesive strength, and can maintain stable high adhesive strength even after thermosetting. Acrylic copolymers for products That.

[Conventional technology]

Heretofore, some thermosetting pressure-sensitive adhesive compositions capable of forming a pressure-sensitive adhesive layer having tackiness at room temperature and being cured by heating are already known.

For example, JP-A-52-121644 describes a "pressure-sensitive adhesive composition mainly containing a mixture of a copolymer having a functional group capable of reacting with an epoxy resin and a polyhydric alcohol glycidyl ether". And, as a monomer having this "functional group capable of reacting with the epoxy resin",
"Β-hydroxyethyl acrylate or methacrylate, β-hydroxypropyl acrylate or methacrylate, allyl alcohol, glycidyl acrylate or methacrylate, glycidyl allyl ether" and the like are exemplified. And in the first embodiment,
A pressure-sensitive adhesive composition in which polyethylene glycol diglycidyl ether, which is a water-soluble epoxy resin, was added to an emulsion copolymer obtained by copolymerizing 2.5% by weight of glycidyl methacrylate, and in Example 3, 2% by weight of β-hydroxypropyl acrylate and There are disclosed pressure-sensitive adhesive compositions in which pentaerythritol diglycidyl ether is added to an ethyl acetate / acetone solution polymer obtained by copolymerizing 0.2% by weight of dimethylaminoethyl methacrylate.

However, in the above-mentioned proposal, what is characteristic of the acrylic copolymer of the present invention is that there is no specific description about a copolymer obtained by copolymerizing both an epoxy group-containing monomer and a hydroxyl-containing monomer in a specific amount. No description, and in the proposed pressure-sensitive adhesive composition, the amount of the epoxy resin is too small,
For example, the adhesive strength at a high temperature such as 100 ° C. or more is completely insufficient, and even if the amount of the epoxy resin is increased, the compatibility with the epoxy resin is reduced, the adhesiveness is almost lost, and thermosetting is performed. Thereafter, the room temperature adhesive strength was reduced, and the high temperature adhesive strength was slightly improved.

Further, for example, JP-A-63-312380 discloses that a monomer which forms a polymer having an adhesive Tg of -50 ° C. or less is mainly used for an epoxy resin, preferably a bisphenol type epoxy resin having an average molecular weight of about 1,000 or less. As a component, a component that forms a polymer having a Tg of 0 ° C. or higher for improving cohesion and a carboxyl group, a hydroxyl group, an epoxy group, a methylol group, an alkoxymethyl group, an amino group, an amide group,
A copolymer obtained by copolymerizing a reactive monomer containing a functional group such as an allyl group (particularly preferably a reactive monomer having a hydroxyl group) is used in an amount of 30 to 200 parts by weight based on 100 parts by weight of the epoxy resin. Partially formulated thermosetting pressure-sensitive adhesive compositions are described. Example 1 of this proposal includes 70 parts by weight of “Epicoat 828” and 30 parts by weight of “Epicoat 1001”.
A composition comprising 100 parts by weight of a commercially available acrylic pressure-sensitive adhesive, 5 parts by weight of dicyandiamide, and an amine-based curing accelerator is disclosed. In Example 1 (c), the commercially available acrylic pressure-sensitive adhesive contains a hydroxyl group. The use of a compound containing 3 mol% of hydroxyethyl acrylate and the use of a compound containing an epoxy group are disclosed in Example 1 (d).

However, similarly to the first proposal, the second proposal does not describe an acrylic copolymer obtained by copolymerizing both an epoxy group-containing reactive monomer and a hydroxyl group-containing reactive monomer. There is no description or suggestion as to the excellent effect of copolymerizing both the reactive monomer and the hydroxyl-containing reactive monomer. Also, when using the composition of the second proposal,
It is difficult to say that the compatibility between the epoxy resin and the acrylic copolymer and the room temperature adhesion after the thermosetting of the obtained adhesive layer is insufficient, and the high-temperature adhesion is insufficient. Even when the mixing ratio was increased, no remarkable improvement in high-temperature adhesive strength was observed.

[Problems to be solved by the invention]

The present inventors have solved the above-described problems of the conventional thermosetting pressure-sensitive adhesive composition, and can be blended with the epoxy resin in various ratios. Regardless of the compounding ratio, the obtained adhesive composition is excellent in various stability, has high tackiness before thermosetting, and always maintains high adhesive strength after thermosetting. In particular, in the case of a composition having a large proportion of an epoxy resin, an acrylic copolymer for an excellent thermosetting pressure-sensitive adhesive composition capable of exhibiting high adhesive strength even at a high temperature such as 100 ° C. or more. As a result of conducting research to obtain a copolymer, an acrylic copolymer having a number average molecular weight of about 90,000 consisting of 80% by weight of ethyl acrylate, 10% by weight of glycidyl methacrylate and 10% by weight of 2-hydroxyethyl methacrylate is an example. For example, it has good compatibility with epoxy resin curing agents such as bisphenol A type epoxy resin having an epoxy equivalent of about 185 (liquid at normal temperature) and dicyandiamide (hereinafter sometimes abbreviated as DICY). Thermosetting pressure-sensitive adhesive compositions containing various proportions of epoxy resin and DICY are excellent in compounding stability.For example, they are separated and settled even when left at room temperature for 1 week or more, and become thickened gel. These compositions are applied to an appropriate adherend such as an aluminum plate.
When dried, acrylic copolymer, epoxy resin and DI
A highly stable pressure-sensitive adhesive layer that has excellent tackiness regardless of the CY compounding ratio, and another suitable adherend is layered on this layer. In particular, in a pressure-sensitive adhesive layer from a composition having a large proportion of an epoxy resin, the pressure-sensitive adhesive layer has excellent high-temperature adhesive strength, and the adhesive composition is stored at room temperature for about one month, for example. In addition, the inventors have found that the adhesive properties are hardly impaired, and further studied to complete the present invention.

[Means for solving the problem]

The present invention relates to an acrylic copolymer used in a thermosetting pressure-sensitive adhesive composition comprising an acrylic copolymer (A), an epoxy resin (B) and an epoxy resin curing agent (C), wherein the copolymer is (A) the following monomers a to e, a. A monomer having an epoxy group 5 to 40% by weight, b. An acrylic acid or methacrylic acid ester monomer 5 having a hydroxyl group represented by the following general formula: ~ 20% by weight, c. 50 to 90% by weight of acrylic acid or methacrylic acid ester monomer represented by the following general formula, d. a monomer having at least one functional group in addition to the radically polymerizable unsaturated group, and 0 to 15% by weight of a monomer other than the monomers a and b, and e. 0 to 50% by weight of a comonomer other than the monomers a to d, which is copolymerizable with the monomers a to d (provided that the total of the monomers a to e is 100% by weight) It is an object of the present invention to provide an acrylic copolymer for a thermosetting pressure-sensitive adhesive composition, which is an acrylic copolymer obtained by copolymerization and having a number average molecular weight of 50,000 or more. Things.

 Hereinafter, the present invention will be described in detail.

The acrylic copolymer (A) for a thermosetting pressure-sensitive adhesive composition of the present invention is obtained by copolymerizing a monomer (a) having an epoxy group.

Examples of the monomer (a) include (meth) acrylates of epoxy group-containing alcohols such as glycidyl methacrylate and glycidyl acrylate; and epoxy group-containing alcohols such as glycidyl allyl ether, glycidyl methallyl ether, and glycidyl vinyl ether. (Meth) allyl alcohol or vinyl ethers; Of these, use of glycidyl methacrylate (hereinafter sometimes abbreviated as GMA) is preferred from the viewpoints of availability and good copolymerization reactivity.

As described above, the amount of the monomer (a) having an epoxy group is determined by the sum of the monomers constituting the acrylic copolymer (A) (hereinafter, may be abbreviated as the total amount of monomers). 5 to 40% by weight, preferably 5 to 30% by weight based on the weight%
It is. If the copolymerization amount of the monomer (a) exceeds the upper limit and is too large, problems such as lack of smooth copolymerization reaction, difficulty in obtaining a homogeneous copolymer, and, in some cases, gelation may occur. In addition to this, the resulting pressure-sensitive adhesive layer tends to have a reduced adhesive strength after curing, which is not preferable. on the other hand,
If the copolymerization amount is less than the lower limit, the compatibility with the epoxy resin (B) and the blending stability may decrease, and the adhesive strength after the curing may be insufficient.

The acrylic copolymer (A) of the present invention is an acrylic or methacrylic acid ester monomer (b) having a hydroxyl group represented by the following general formula together with the monomer (a).
Are copolymerized.

Examples of the monomer (b) include (meth) acrylic acid esters of hydroxyl group-containing alcohols such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. can do.

The amount of the acrylic acid or methacrylic acid ester monomer (b) having a hydroxyl group used is 10
It is 5 to 20% by weight, preferably 5 to 15% by weight, based on 0% by weight. If the copolymerization amount of the monomer (b) exceeds the above upper limit and is too large, the adhesiveness of the resulting thermosetting pressure-sensitive adhesive layer tends to decrease, and the adhesiveness after curing also decreases. May be undesirable. On the other hand, if the copolymerization amount is too small, less than the lower limit, the compatibility with the epoxy resin and the blending stability may be reduced, and the adhesive strength may be insufficient.

In the present invention, the total copolymerization amount of the monomers (a) and (b) is 10% with respect to 100% by weight of the total amount of the monomers.
It is preferably from 50 to 50% by weight, especially from 15 to 40% by weight. When the copolymerization amount of the monomers (a) and (b) is equal to or less than the upper limit, the copolymerization reaction proceeds smoothly, a homogeneous copolymer is obtained, and gelation hardly occurs. ,further,
The adhesive strength of the resulting adhesive composition or adhesive sheet is also preferably maintained at a high level. On the other hand, when the copolymerization amount is not less than the lower limit value, it is preferable because not only the compatibility with the epoxy resin and the blending stability, but also the adhesive strength is excellent.

The acrylic copolymer (A) of the present invention further contains, as a copolymerization component, a monomer (c) represented by the following general formula together with the monomers (a) and (b).

Examples of radicals R ⁴ in the monomer (c), a methyl group, an ethyl group, n- propyl group, n- butyl group, i- butyl, t- butyl group, n- hexyl, n- octyl Group, i-octyl group, 2-ethylhexyl group, i-nonyl group, n-dodecyl group, stearyl group and the like, and specific examples thereof include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, Acrylic ester monomers such as n-butyl acrylate, i-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, i-nonyl acrylate, stearyl acrylate;
Methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, n-
Methacrylic acid ester monomers such as hexyl methacrylate, n-octyl methacrylate, i-octyl methacrylate, 2-ethylhexyl methacrylate, i-nonyl methacrylate, n-dodecyl methacrylate, i-dodecyl methacrylate, and stearyl methacrylate; be able to.

The amount of the monomer (c) used is 100
It is 50 to 90% by weight, preferably 60 to 85% by weight in the weight%. If the amount of the monomer (c) is too large, exceeding the upper limit, the compatibility with the epoxy resin (B) and the blending stability may decrease, and the resulting pressure-sensitive adhesive may be used. Adhesion after heat curing of the layer is also unsatisfactory because it is insufficient.On the other hand, if it is less than the lower limit, the copolymerization reaction may lack smoothness, making it difficult to obtain a homogeneous copolymer, In some cases, there are problems such as gelation,
The adhesiveness of the adhesive layer and the adhesive strength after curing tend to decrease, which is not preferable.

Further, the acrylic copolymer (A) of the present invention is a monomer having at least one functional group in addition to the radically polymerizable unsaturated group, together with the monomers (a) to (c). And a monomer (d) other than the monomers (a) and (b)
Can be contained as a copolymerization component. Examples of such a monomer (d) include monomers having a functional group such as a carboxyl group, an amide group or a substituted amide group, an amino group or a substituted amino group, and a mercapto group. In the present invention, one or more of these monomers can be appropriately selected and used.

Specific examples of these monomers include, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, citraconic acid (preferably acrylic acid, methacrylic acid, itaconic acid) and the like. Carboxyl group-containing monomers; for example, acrylamide,
Methacrylamide, N, N-dimethylacrylamide, N
Amide group- or substituted amide group-containing monomers such as -methylacrylamide, N-methylolacrylamide, Nn-butoxymethylacrylamide (preferably acrylamide and methacrylamide); for example, aminoethyl acrylate, N, N-dimethylamino Ethyl acrylate, N, N-diethylaminoethyl acrylate, N, N
-Dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, (preferably N, N-
Amino- or substituted amino-group-containing monomers such as dimethylaminoethyl methacrylate and N, N-diethylaminoethyl methacrylate); and mercapto-group-containing monomers such as vinyl mercaptan and allyl mercaptan. These monomers (d)
Among them, a carboxy group-containing monomer, an amide group-containing monomer and a substituted amino group-containing monomer can be suitably used.

The amount of the monomer (d) used is 100% by weight of the total amount of the monomer.
In contrast, for example, an amount of about 0 to 15% by weight can be exemplified.

Further, the acrylic copolymer (A) of the present invention may contain the monomers (a) to (d) together with the monomers (a) to (d).
A comonomer (e) other than (a) to (d) copolymerizable with (d) can be contained as a copolymer component. Examples of such a comonomer (e) include saturated fatty acid vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, and vinyl versatate;
Dibutyl maleate, dibutyl fumarate, dibutyl itaconate, dioctyl malate, dioctyl fumarate, alpha such as dioctyl itaconate, beta-straight or branched alkyl diester of C ₁ -C ₁₈ unsaturated dicarboxylic acids; for example, Examples thereof include aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, and ethylvinylbenzene; and vinyl cyanide monomers such as acrylonitrile and methacrylonitrile.

The amount of the comonomer (e) to be used is generally 0 to 50% by weight, preferably about 0 to 30% by weight, based on 100% by weight of the total amount of the monomers. Since the use of the comonomer (e) can vary depending on the type of the comonomer, the amount of the comonomer cannot be uniquely determined, but the balance between the adhesive force and the tackiness and the phase with the epoxy resin are not determined. It can be appropriately selected within a range that does not impair the solubility and the blending stability.

The acrylic copolymer (A) for a thermosetting pressure-sensitive adhesive composition of the present invention has a number average molecular weight (hereinafter sometimes abbreviated as ▲) of 50,000 or more, preferably 80,000 to 200,000.
If the ▼ of the copolymer (B) is too small below the lower limit, the tackiness and the initial adhesive strength tend to be insufficient, which is not preferred. In addition, since it is not easy to produce a copolymer in which ▼ exceeds 200,000, it is preferable to adjust ▼ to fall within the above range. The weight average molecular weight of the copolymer (B) (hereinafter sometimes abbreviated as ▼) is generally 100,000 or more, preferably 200,000 or more, particularly preferably 300,000 to 1,000,000. good. If ▼ is not less than the lower limit, it is preferable because the adhesiveness and initial adhesive strength are excellent.On the other hand, if it is not more than the upper limit, the production can be relatively easily carried out. It is better to adjust it. These ▲ ▼ and ▲ ▼
Are determined based on values measured by gel permeation chromatography (hereinafter abbreviated as GPC).

The glass transition point (hereinafter sometimes abbreviated as Tg) of the acrylic copolymer (A) is generally 100 ° C. or lower, preferably 30 ° C. or lower, more preferably 0 ° C. or lower, further preferably −5 ° C. or lower. ° C or lower, particularly preferably -10 to -40
° C. When the Tg is equal to or lower than the upper limit temperature, the obtained thermosetting pressure-sensitive adhesive layer has excellent tackiness and initial adhesiveness, which is preferable. If Tg is -40 ° C or higher,
It is preferable because the adhesive strength of the adhesive layer after heat curing is particularly excellent.

The glass transition point (Tg) of the acrylic copolymer (A) of the present invention is a value measured and determined as follows.

Glass transition point: about 0.05mm thick aluminum foil,
In a cylindrical cell having an inner diameter of about 5 mm and a depth of about 5 mm, about 10 mg of a sample of an organic solvent solution of about 50% by weight of an acrylic copolymer is weighed,
A sample dried at 100 ° C. for 2 hours was used as a measurement sample, and a SSC-5000 type differential calorimeter (Dif.
(Ferential Scanning Calorimeter) at a measurement start temperature of -150 ° C and a heating rate of 10 ° C / min.

The method for polymerizing the acrylic copolymer (A) of the present invention is not particularly limited, and known methods such as solution polymerization and emulsion polymerization can be employed. In producing the thermosetting pressure-sensitive adhesive composition, it is preferable to employ solution polymerization in which a processing step is relatively simple and can be performed in a short time.

In the solution polymerization, generally, a predetermined organic solvent, a monomer, a polymerization initiator, and a chain transfer agent used as needed are charged in a polymerization tank, and the mixture is stirred in a nitrogen stream or at the reflux temperature of the organic solvent. The reaction is carried out by heating for several hours. In this case, at least a part of the organic solvent, the monomer, the polymerization initiator and / or the chain transfer agent may be sequentially added.

As the organic solvent for polymerization, for example, benzene,
Aromatic hydrocarbons such as toluene, xylene and aromatic naphtha; fats such as n-hexane, n-heptane, n-octane, i-octane, n-decane, cyclohexane, dipentene, petroleum spirit, petroleum naphtha and turpentine oil Aliphatic or alicyclic hydrocarbons; esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, 3-methoxybutyl acetate, methyl benzoate, cellosolve acetate, butyl cellosolve acetate; acetone, methyl ethyl ketone, methyl isobutyl Ketones such as ketone, isophorone, cyclohexanone and methylcyclohexanone; glycol ethers such as ethylene glycol methyl ether, ethylene glycol ethyl ether and ethylene glycol butyl ether;
Examples include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol, t-butyl alcohol, and the like. These organic solvents can be used alone or in combination of two or more.

In addition, the thermosetting pressure-sensitive adhesive composition manufactured using the acrylic copolymer (A) of the present invention may be, if necessary,
A solution of a solvent containing a polar organic solvent as a main component capable of dissolving the epoxy resin (B) and the epoxy resin curing agent (C) described below can be used. In that case, among the above-mentioned organic solvents for polymerization, It is preferable to use an organic solvent having a boiling point of 50 to 150 ° C, particularly 60 to 100 ° C, which can be easily replaced with a polar organic solvent by volatilizing the organic solvent for polymerization from the obtained copolymer solvent. It is particularly preferable to use an organic solvent such as toluene, n-hexane, ethyl acetate, acetone, methyl ethyl ketone, methyl alcohol and n-propyl alcohol.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, t-
Organic peroxides such as butyl peroxybivalate; for example, 2,2'-azobis-i-butyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-4-methoxy Azo compounds such as -2,4-dimethylvaleronitrile; and the like can be used alone or in combination. The amount of the polymerization initiator used was 10
Generally, about 0.01 to 1.0 part by weight, preferably about 0.02 to 0.5 part by weight, is used based on 0 part by weight.

Further, as the chain transfer agent, for example, cyanoacetic acid; alkyl cyanoacetate esters alkyl group C ₁ -C _8; bromoacetic acid esters alkyl group C ₁ -C _8;; bromoacetate anthracene, phenanthrene, fluorene, 9
Aromatic compounds such as -phenylfluorene; aromatic nitro compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, p-nitrotoluene; benzoquinone, 2,3,5,
Benzoquinone derivatives such as 6-tetramethyl-p-benzoquinone; borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloro Halogenated hydrocarbons such as methane, tribromomethane and 3-chloro-1-propene; aldehydes such as chloral and furaldehyde; alkyl mercaptans having ₁ to ₁₈ carbon atoms; aromatic mercaptoacetic acids such as thiophenol and toluene mercaptan Mercaptoacetic acid; C _{1 of} mercaptoacetic acid
-C ₁₀ alkyl esters; hydroxamate Le alkyl mercaptans of C ₁ -C _12; Binen, terpenes such Tapinoren; can be exemplified.

When the above-mentioned chain transfer agent is used, its amount is preferably about 0.005 to 3.0 parts by weight per 100 parts by weight of the total amount of the monomers.

The polymerization temperature is generally in the range of about 30 to 180 ° C, preferably about 60 to 150 ° C.

The acrylic copolymer solution of the present invention thus obtained usually contains the acrylic copolymer in an amount of 20 to 90% by weight.

The acrylic copolymer (A) of the present invention can be made into a thermosetting pressure-sensitive adhesive composition by blending it with an epoxy resin (B) and an epoxy resin curing agent (C).

The type of the epoxy resin (B) is not particularly limited, and examples thereof include bisphenols such as bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, and hydrogenated bisphenol A epoxy resin. A type epoxy resin can be exemplified. Other than these, for example, novolak-type epoxy resins such as phenol novolak-type epoxy resin and cresol novolak-type epoxy resin; for example, glycidyl alkyl ether-based epoxy resins such as polyalkylene polyol (such as neopentyl glycol) polyglycidiether; For example, glycidylamine-based epoxy resins such as tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, and tetraglycidyl-m-xylenediamine; for example, diglycidyl phthalate, diglycidyl hexahydrophthalate, Glycidyl ester epoxy resins such as diglycidyl tetrahydrophthalate; for example, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl Cycloaliphatic epoxy resins such as 3,4-epoxycyclohexane) carboxylate and bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate; for example, resins such as triglycidyl isocyanurate and glycidylglycidoxyalkylhydantoin; Examples thereof include a cyclic epoxy resin, and further, a halide of the epoxy resin; an epoxy group-containing resin obtained by reacting a polybasic acid or a polyester polycarboxylic acid with the epoxy resin; a polyglycidyl ester of a polyester polycarboxylic acid And various epoxy resins such as polyglycidyl ether of polyester polyol.

These epoxy resins can be used alone or in combination of two or more of different types or two or more of the same types having different epoxy equivalents. Among these epoxy resins, bisphenol A type epoxy resins and novolak type epoxy resins are preferably used from the viewpoints of easy availability and good adhesive properties of the obtained pressure-sensitive adhesive layer.
It is particularly preferred to use a type epoxy resin.

Further, as such an epoxy resin (B), an epoxy resin (B ₁ ) having an epoxy equivalent of 150 to 300 from the viewpoint of compatibility with the acrylic copolymer (A) of the present invention and good blending stability. It is preferable to use an epoxy resin which is liquid at normal temperature (about 20 ° C.). The acrylic copolymer (A) of the present invention is mixed with the epoxy resin (B) at various ratios to form a heat-sensitive resin. It can be a curable pressure-sensitive adhesive composition.

The amount of the epoxy resin (B) used in such a thermosetting pressure-sensitive adhesive composition is the sum of the acrylic copolymer (A) and the epoxy resin (B) (hereinafter sometimes abbreviated as a resin component). It is preferably from 5 to 95% by weight, especially from 5 to 85% by weight, based on 100% by weight. If the amount of the epoxy resin (B) is at least the lower limit, the adhesive strength after heat curing will not be insufficient, and if it is at most the lower limit, the compatibility of the composition will be impaired. This is preferable because the adhesiveness of the resulting pressure-sensitive adhesive layer does not become too small, the initial adhesive strength is excellent, and the adhesive strength after thermosetting does not decrease.

In particular, in the field where high adhesive strength at high temperature is required, the amount of the epoxy resin (B) used is 45 to 95% by weight, particularly 45 to 85% by weight based on 100% by weight of the total of the resin components. %. In such a range where the amount of the epoxy resin (B) used is large, two or more epoxy resins having different epoxy equivalent values, that is, one or more epoxy resins (B ₁ ) having an epoxy equivalent of 150 to 300 and an epoxy resin By using one or more epoxy resins (B ₂ ) having an equivalent weight of more than 300, the adhesiveness of the obtained pressure-sensitive adhesive layer can be improved.

As such an epoxy resin (B ₂ ), it is preferable to use an epoxy resin having an epoxy equivalent of 400 to 1000 and being solid at ordinary temperature from the viewpoint of good tackiness of the obtained pressure-sensitive adhesive layer. The amount of the epoxy resin (B ₂₎ is from 5 to 40% by weight relative to the total 100 wt% of the resin component, especially 10
It can be in the range of ~ 30% by weight. When the amount of the epoxy resin (B ₂ ) is equal to or more than the lower limit, suitable tackiness is obtained and the initial adhesive strength is also excellent. Coalescing (A)
Is particularly excellent in compatibility with and blending stability.

The thermosetting pressure-sensitive adhesive composition according to the present invention comprises, together with the acrylic copolymer (A) and the epoxy resin (B),
Contains an epoxy resin curing agent (C).

The epoxy resin curing agent (C) has a reactive group that reacts with an epoxy group or a hydroxyl group in the resin component in the molecule of the curing agent, or generates such a reactive group by heating or the like. Compound (hereinafter sometimes referred to as a crosslinkable curing agent) and a catalyst for the ring-opening polymerization reaction of the epoxy group in the resin component in the curing agent molecule, or crosslinkable curing with the epoxy group or hydroxyl group in the resin component And a compound having a group that acts as a catalyst for the reaction with the agent (hereinafter, may be referred to as a catalytic curing agent).

Examples of the crosslinkable curing agent that causes an addition reaction with an epoxy group in the resin component include, for example, linear or aliphatic primary or secondary amines, alicyclic, aromatic or heterocyclic-containing aliphatics. Primary or secondary amines, aromatic primary or secondary amines, polyamidoamines obtained by reacting a polymer of unsaturated fatty acids such as linoleic acid or linolenic acid with polyamines, mercaptan-based compounds, Polybasic acids such as unsaturated fatty acid polymers and octadecanedicarboxylic acid, active hydrogen compound-based curing agents, and the like can be exemplified.
As a curing agent that causes an addition or condensation reaction with a hydroxyl group in a resin component, for example, a phenol resin (resole type),
Examples thereof include amino resins, polyisocyanates, and blocked products of polyisocyanates. Further, an acid anhydride which first undergoes an addition reaction with a hydroxyl group in a resin component and then undergoes an addition reaction with a carboxyl group and an epoxy group, such as an acid anhydride, can also be used.

Examples of the catalytic curing agent include aliphatic, alicyclic or aromatic tertiary amines or salts thereof, imidazoles or salts thereof, amine amide-based curing agents, lylic acid or Bronsted acid salt, urea derivatives and the like. In addition, a polymer of the above-mentioned unsaturated fatty acid, a polybasic acid such as octadecanedicarboxylic acid, and an acid anhydride also have an action as an epoxy group ring-opening polymerization catalyst.

It is preferable that these various curing agents are previously blended with the acrylic copolymer (A) and the epoxy resin (B) as described later. In this case, the viewpoint of the pot life of the blend and the like is considered. Therefore, it is preferable to use a high-temperature activation type curing agent. Among such high temperature activated curing agents, those which can be suitably used in the present invention include, as crosslinkable curing agents, primary or secondary of high temperature activated alicyclic, aromatic or heterocyclic-containing aliphatic. Amines, high temperature activated aromatic primary or secondary
Amines, high-melting active hydrogen compound-based curing agents, acid anhydrides, etc., as catalytic curing agents, amine imide-based curing agents,
High temperature activated tertiary amine or imidazole curing agent,
Examples thereof include a tertiary amine salt or imidazole salt-based curing agent, and a urea derivative-based curing agent.

Examples of the high temperature activated alicyclic, aromatic or heterocyclic-containing aliphatic primary or secondary amines include, for example, 4-amines.
Amino-2,2,6,6-tetramethylpiperidine, bis (4
-Amino-3-methyldiclohexyl) methane, 2,4-
Dihydrazino-6-methylamino-s-triazine and the like; and high-temperature activated aromatic primary or secondary amines such as diaminodiphenyl sulfone and diaminodiphenylmethane; and a high melting point active hydrogen compound-based curing agent. As, for example, dicyandiamide; for example,
Adipic hydrazide, 5-t-butylhydantorene-
1,3-di (carboxyethyl) dihydrazide [Amicure VDH (trade name), Ajinomoto Co., Ltd.], octadecane-1,1
8-dicarboxylic dihydrazide [Amicure LDH (trade name), Ajinomoto Co., Ltd.], octadeca-7,11-diene-1,
Examples thereof include organic acid dihydrazides such as 18-dicarboxylic acid dihydrazide [Amicure UDH (trade name), Ajinomoto Co., Ltd.].

Examples of the acid anhydride include maleic anhydride, dodecyl succinic anhydride, polyadipic anhydride, polyazeleic anhydride, polysebacic anhydride, poly (ethylene octadecanic acid) anhydride, and poly (phenylhexadecanein) Acid) aliphatic acid anhydrides such as anhydrides; for example, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride,
Alicyclic acid anhydrides such as trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride and methylhymic anhydride; for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride,
Examples thereof include aromatic acid anhydrides such as benzophenone tetracarboxylic anhydride, ethylene glycol bis trimellitate, and glycerol tris anhydride trimellitate.

Further, as amine imide-based curing agents, trialkyl hydrazinium fatty acid amides [YPH103, YPH201, YPH208]
(Trade name), Yuka Shell Epoxy Co., Ltd.], as a high temperature activated tertiary amine or imidazole-based curing agent,
2,4,6-tris (dimethylaminomethyl) phenol,
2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-methylimidazole, and the like, as a tertiary amine salt or imidazole salt-based curing agent, Amicure PN-23, MY-24 (trade name) [Ajinomoto Co., Ltd.] uses Lewis acid or Bronsted acid salt-based curing agent as a Lewis acid salt such as boron trifluoride monoethylamine salt; for example, Bronsted acid aliphatic sulfonium salt [Opton CP-66] , CP-77 (trade name), Asahi Denka Co., Ltd.], and examples of urea derivative-based curing agents include N, N-dimethylurea, N, N'-dimethylurea, N, N'- Diethyl urea, N-phenyl urea,
N, N-diphenylurea, N, N, N'-triphenylurea, N,
N, N ', N'tetraphenylurea, N-acetylurea, N,
N'-diacetyl urea, N-acetyl-N'-methyl urea, N-benzyl urea, N, N-dibenzoyl urea, N-
Benzenesulfonylurea, Np-toluenesulfonylurea, Np-toluenesulfonyl-N'-n-butylurea, Np-toluenesulfonyl-N'-i-butylurea, N, N-dimethyl-N ' -(3 ', 4'-dichlorophenyl) urea, parabanic acid, N, N'-dimethylparabanic acid, N, N'-dimethylbarbituric acid, 5,5-dimethylhydantoin, 1,3-dimethyluracil, 1 , 5-dimethyluracil and the like.

Among these curing agents, from the viewpoints of the pot life of the obtained thermosetting pressure-sensitive adhesive composition and the bonding performance of the composition and the thermosetting pressure-sensitive adhesive sheet, a high-temperature activation type crosslinkable curing is preferred. It is particularly preferable to use dicyandiamide (DICY), diaminodiphenylsulfone, diaminodiphenylmethane or the like as an agent. Further, for example, when using a high-temperature active type crosslinkable curing agent such as DICY, the above tertiary amine salt-based curing agent as a high-temperature active type catalytic curing agent,
The thermosetting temperature can be lowered by using a urea derivative-based curing agent in combination.

Among these epoxy resin curing agents (C), the crosslinkable curing agent is used in the case of the active hydrogen compound-based curing agent and the aromatic amine with respect to one epoxy group in the resin component. The number of active hydrogen is usually 0.2 to 2.0, preferably 0.1.
In the case of an acid anhydride, the number is preferably from 0.2 to 2.0, and more preferably from 0.5 to 1.0. Further, a catalytic curing agent such as an amineimide-based curing agent, a tertiary amine or imidazole salt-based curing agent, a Lewis acid or Bronsted acid salt-based curing agent is preferably used in combination with a crosslinkable curing agent. In general, the amount can be about 40 parts by weight or less based on 100 parts by weight of the crosslinking hardener.

These epoxy resin curing agents (C) may be previously blended with a resin component composed of the acrylic copolymer (A) and the epoxy resin (B). May be blended. However, in order to avoid complication of the operation at the time of use, it is preferable that the curing agent is previously blended with the components (A) and (B). The method of compounding the curing agent is not particularly limited, but it is preferable to dissolve the curing agent in a soluble organic solvent before compounding, from the viewpoint of ease of compounding and the like.

The organic solvent is preferably one that dissolves both the resin component and the epoxy resin curing agent.As such an organic solvent, a polar organic solvent is generally used, for example, methyl ethyl ketone, methyl cyclohexanone, diacetone. Ketones such as alcohols; for example, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-i-propyl ether,
Ethylene glycol butyl ether, diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol dimethyl ether (tetraglyme)
Glycol ethers such as ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol-i-propyl ether acetate; glycol esters such as dimethyl sulfoxide, dimethyl sulfone, tetramethyl sulfone, dimethyl formamide; Other aprotic polar organic solvents such as dimethylacetamide, hexamethylphosphoric triamide, N-methylpyrrolidone, and acetonitrile;

The thermosetting pressure-sensitive adhesive composition according to the present invention may further include, if necessary, for example, coumarone-indene resin, terpene-phenol resin, pt-butylphenol-acetylene resin, phenol-formaldehyde resin, terpene resin, xylene A tackifying resin such as formaldehyde resin, petroleum hydrocarbon resin, hydrogenated hydrocarbon resin, rosin derivative, turpentine resin;
Other modifying resins such as a vinyl acetate copolymer resin, an ethylene-acrylic copolymer resin, and an ethylene-vinyl acetate-acrylic copolymer resin can be added. The added amount of these resins is a total of 100
With respect to parts by weight, tackifying resin, for example, 0 to 60 parts by weight, particularly 0 to 40 parts by weight; other modifying resin, for example, 0 to 50 parts by weight, particularly 0 to 20 parts by weight; Is good.

In addition to these, the pressure-sensitive adhesive composition according to the present invention may be, if necessary, for example, a phthalic acid ester such as dioctyl phthalate, a phosphate ester such as tricresyl phosphate, polybutene, a process oil, or the like. Plasticizers; for example, organic or inorganic coloring agents such as titanium oxide, carbon black, and phthalocyanine blue; inorganic fillers such as clay, talc, calcium carbonate, silica, aluminum hydroxide, and glass powder; Thickeners such as anhydrous silica [Aerosil 300 (trade name), manufactured by Nippon Aerosil Co., Ltd.] and activated ultrafine calcium carbonate [white luster CCR (trade name), Shiraishi Industry Co., Ltd.]; UV absorber; Known additives such as preservatives may be added.

As a method for producing the thermosetting pressure-sensitive adhesive composition according to the present invention, for example, the epoxy resin (A) may be added to the organic solvent solution of the acrylic copolymer (A) of the present invention obtained as described above. B) and various additives that can be added as required are blended in predetermined amounts, respectively, and then an epoxy resin curing agent (C) and a polar organic solvent capable of dissolving and dispersing the epoxy curing agent (C) are added, Further, a method in which an appropriate organic solvent is added as necessary and uniformly mixed can be suitably employed. If necessary, before adding the epoxy resin curing agent (C) and the polar organic solvent for dissolving and dispersing the curing agent, the acrylic copolymer (A) solution, the epoxy resin (B), and the The resulting mixture of various additives is stirred and mixed while heating, and the organic solvent for polymerization is removed by a known method such as distillation, and the acrylic copolymer (A), the epoxy resin (B), and, if necessary, It can also be a molten mixture consisting of various additives added.

The resulting organic solvent solution of the thermosetting pressure-sensitive adhesive composition usually has a solid content of about 30 to 70% by weight and a viscosity (B-type rotational viscometer, 25 ° C., 10 RPM; hereinafter, measurement conditions are the same). ~ 20,
000 cps, preferably about 300 to 5,000 cps.

The thermosetting pressure-sensitive adhesive composition according to the present invention is directly applied to one or both of the adherends by a generally known coating means such as a knife coater, a roll coater, an air coater, a spray coater, and the like, and then dried. By joining them together and pressurizing and heat-curing them as necessary, they can be firmly bonded. The drying temperature is preferably a temperature at which curing of the pressure-sensitive adhesive layer does not occur, for example, about 50 to 120 ° C. The curing temperature varies depending on the type of the epoxy resin curing agent (C), but is generally about 100 to 250 ° C.

Examples of the adherend to which the thermosetting pressure-sensitive adhesive composition according to the present invention can be suitably used include metal, glass, plastic, wood, paper, slate, rubber, decorative board and the like.

In addition, the thermosetting pressure-sensitive adhesive composition according to the present invention may be, for example, a non-woven fabric, a woven fabric, a knitted fabric, paper, or a single-sided surface of various substrates such as a plastic film, by the same generally known coating means as described above. Applied on both sides at an appropriate thickness, or, for example, a suitable amount of a nonwoven fabric, a woven fabric, a knitted fabric, a base material such as paper is impregnated and dried, and a release material is formed on the obtained pressure-sensitive adhesive layer. Can be obtained as a thermosetting pressure-sensitive adhesive sheet. Furthermore, a "coreless" double-sided pressure-sensitive adhesive sheet can also be obtained by directly applying the pressure-sensitive adhesive composition on a release material, drying the composition, and then placing the release material on the surface. The thickness of the pressure-sensitive adhesive layer is generally about 10 to
It is good to be about 300μ, preferably about 20 to 300μ. Drying is preferably performed at the same temperature as above, that is, about 50 to 120 ° C.

The obtained thermosetting pressure-sensitive adhesive sheet can be firmly bonded by pressure-bonding to a desired portion of the adherend as described above and then heating and curing while applying pressure as necessary. In the case of a thermosetting double-sided pressure-sensitive adhesive sheet, adherends of the same type or different types can be firmly bonded to each other via the double-sided pressure-sensitive adhesive sheet.

The thermosetting pressure-sensitive adhesive composition according to the present invention, for example,
It is good to store at a low temperature of 10 ° C. or less, preferably 0 ° C. or less.
It is preferable to select the type and amount of the epoxy resin curing agent (C) so that the pot life is at least one week, the adhesive properties are not changed, and the adhesive properties of the adhesive sheet are not changed for one month or more.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples and Comparative Examples.

In addition, the compatibility and pot life test method of the thermosetting pressure-sensitive adhesive composition according to the present invention, and the initial adhesive force and the adhesive force measuring method of the adhesive layer are as follows.

(1) Compatibility test The composition solution is left in a closed state at 25 ° C. for 24 hours, and the uniformity, transparency and presence or absence of sediment of the solution are visually observed and evaluated according to the following criteria.

 ○ ‥‥‥ The composition solution is uniform and transparent, with no sediment.

Δ ‥‥‥ The composition solution is uniform, but slightly cloudy or sedimented.

× ‥‥‥ Composition solution separated or opaque, or sedimented.

(2) Pot life test (2-1) Appearance The state after leaving the composition solution in a closed state at 25 ° C. for 7 days is evaluated according to the following criteria.

 ◎ ‥‥‥ Almost no change in appearance and viscosity.

 ○ ‥‥‥ No change in appearance, but slightly increased viscosity.

Δ ‥‥‥ No change in appearance, but large increase in viscosity (fluidity).

× ‥‥‥ Extremely high viscosity increase (no fluidity), or
Gelation.

(2-2) Adhesive property The adhesive property was measured according to the following items (3) to (5) using the composition solution left in a closed state at 25 ° C for 7 days,
The evaluation is made according to the following criteria as compared with the case where the composition solution before standing is used.

◎ ‥‥‥ Almost no change in initial adhesive strength and adhesive strength (decrease rate less than 10%).

○ ‥‥‥ Initial adhesive strength, decrease rate of adhesive strength, one is less than 10% and the other is 10 to 30%.

△ ‥‥‥ Initial adhesive strength, rate of decrease in adhesive strength, one is less than 10% and the other 30-50%, or both 10-30%.

× ‥‥‥ Initial adhesive strength, rate of decrease in adhesive strength, 50% or more for one or 30% or more for both.

(3) Measurement of initial adhesive strength 0.2m thickness specified in JIS H-4000 alloy number A-1050P
The surface of the aluminum plate of m is washed with methanol impregnated gauze, and a pressure-sensitive adhesive composition solution (solid content: 50 to 60% by weight, adjusted to a viscosity of about 500 cps) so as to cover about half of the surface,
Apply with a doctor blade so that the thickness after drying is about 100μ, dry in a hot air circulating dryer at 100 ° C for 5 minutes, and then place another sheet on the pressure-sensitive adhesive layer formed Place an aluminum plate treated in the same manner as in
Into a test piece by crimping according to the method described above. Twenty minutes later, the test piece was cut to a width of 25 mm, and one of the aluminum plates (the part without the pressure-sensitive adhesive layer) was bent to about 90 mm.
20 ° C, 65% RH,
Peel strength (Kg / 25mm) under the condition of peel speed 300mm / min
Is measured.

The value of the initial adhesive force of the pressure-sensitive adhesive composition is 0.5 K
g / 25 mm or more, and particularly preferably 1.0 kg / 25 mm or more.

(4) Measurement of Adhesive Strength (4-1) Measurement of Adhesive Strength at Room Temperature After heat-curing the test piece prepared in the section (3) under predetermined conditions, the test piece was allowed to stand at 25 ° C. for 24 hours. )
The peeling height (Kg / 25mm) is measured in the same manner as in the test method described in the section. The adhesive strength is preferably 4 kg / 25 mm or more, more preferably 5 kg / 25 mm or more, and 6 kg / 25 mm.
The above is particularly preferred.

(4-2) Measurement of high-temperature adhesive force After the test specimen prepared in the preceding paragraph (3) was cured by heating under predetermined conditions, it was allowed to stand at 25 ° C. for 24 hours, and then in a thermostatic chamber adjusted to a predetermined temperature. For about 10 minutes or more,
Except for the measurement in the constant temperature bath, the peel strength (Kg / 25 mm) is measured in the same manner as in the test method in the section (3).

Example 1 In a separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a sequential dropping device, 50 parts by weight of an organic solvent for initial addition and ethyl acetate (EAc) as a polymerization initiator and azobisisobutyronitrile were used. (AIBN) 0.025 parts by weight, and then 25 parts by weight of a monomer mixture consisting of 80 parts by weight of ethyl acrylate (EA), 10 parts by weight of glycidyl methacrylate (GMA) and 10 parts by weight of 2-hydroxyethyl acrylate (2HEA) To the reflux temperature (about 80
C) for about 20 minutes. Then, at reflux temperature conditions, 75% by weight of the remaining monomer mixture, 25 parts by weight of EAc and AIBN
0.125 parts by weight of a polymerization initiator solution was sequentially dropped over about 90 minutes, and further about 60 minutes EAC 12.5 parts by weight and AIBN
After adding a polymerization initiator solution consisting of 0.25 parts by weight, 75 parts by weight of toluene was added to dilute the mixture, and the solid content was about 40% by weight.
A solution of an acrylic copolymer of 2550 cps was obtained. ▲ ▼ of this copolymer is about 110,000, ▲ ▼ is about 450,000, and Tg is -20.
° C.

Examples 2 and 3 and Comparative Examples 1 and 2 A solution of an acrylic copolymer was obtained in the same manner as in Example 1 except that the use ratio of GMA and 2HEA was changed. The copolymer composition and viscosity of these acrylic copolymer solutions,
And ▲, ▲ ▼ and Tg of the copolymer
It is shown in the table.

Example 4 An acrylic copolymer solution was obtained in the same manner as in Example 1 except that the ratio of EA to GMA was changed. Table 1 shows the monomer composition and viscosity of this acrylic copolymer solution, and ▲, ▼, and Tg of the copolymer.

Comparative Example 3 In the same apparatus as in Example 1, toluene 50 was used as an organic solvent.
Parts by weight, 10% by weight of the same monomer mixture as in Example 1
And 0.025 parts by weight of a polymerization initiator (AIBN), and polymerization was carried out for about 20 minutes under reflux temperature conditions. Then, the remaining amount of the monomer mixture was 90% by weight under reflux temperature conditions, 8.3 parts by weight of toluene and A
The polymerization initiator solution consisting of 0.125 parts by weight of IBN and the polymerization initiator solution consisting of 8.3 parts by weight of toluene and 0.25 parts by weight of AIBN were added successively dropwise over about 90 minutes, and the acrylic copolymer was further added for about 60 minutes. Was obtained. Table 1 shows the viscosity and solid content of the acrylic copolymer solution, and ▲, ▼, and Tg of the acrylic copolymer and the lyl copolymer.

Example 5 An acrylic copolymer was prepared in the same manner as in Example 1 except that 80 parts by weight of EA was used instead of 80 parts by weight of EA, and the ratio of the initial addition and the sequential addition of the organic solvent was changed. Was obtained. Table 1 shows initial polymerization conditions and viscosities of the acrylic copolymer solution, and ▲, ▼ and Tg of these copolymers.

Example 10 75 parts by weight of the acrylic copolymer solution obtained in Example 1 and Epicoat 815 as the epoxy resin (B)
[(Trade name), bisphenol A type epoxy resin (epoxy equivalent: about 185), manufactured by Yuka Shell Epoxy Co.] 70 parts by weight are added and mixed, and then 4.5 parts by weight of dicyandiamide (DICY) is used as an epoxy resin curing agent. A solution prepared by dissolving 20 parts by weight of dimethylformamide (where the number of active hydrogens per molecule of DICY is 4 and the number of active hydrogens per epoxy group is about 0.54) and an organic solvent for adjusting viscosity (dimethylformamide / ethylene glycol) Monomethyl ether = 1:
1) 10 parts by weight were added, stirred and uniformly mixed to produce a thermosetting pressure-sensitive adhesive composition. The obtained thermosetting pressure-sensitive adhesive composition had a solid content of about 55% by weight and a viscosity of about 600 cps. Table 2 shows the basic properties such as the compatibility and pot life of the composition and the adhesive properties of the composition.

Example 11 In Example 10, instead of using 75 parts by weight of the acrylic copolymer solution and 70 parts by weight of Epicoat 815 obtained in Example 1, using 200 parts by weight of the acrylic copolymer and 20 parts by weight of Epicoat 815, A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used and the amount of the organic solvent for adjusting the viscosity were adjusted according to the change in the number of epoxy groups. Table 2 shows the composition, basic physical properties, and measurement results of the adhesive properties of the obtained thermosetting pressure-sensitive adhesive composition. FIG. 1 shows the change in the room temperature adhesive force with respect to the mixing ratio of the acrylic copolymer and the epoxy resin (B) in Example 1.

Examples 12 to 14 In Example 10, the use ratio of the acrylic copolymer (A) solution of Example 1 and the epoxy resin (B) was changed.
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used and the amount of the organic solvent for adjusting the viscosity were adjusted according to the change in the number of epoxy groups. Table 2 shows the composition of the resulting thermosetting pressure-sensitive adhesive composition, basic physical properties, and measurement results of the adhesive properties of the composition. FIG. 1 shows the change in the room temperature adhesive force with respect to the mixing ratio of the acrylic copolymer (A) and the epoxy resin (B).

Example 15 In Example 10, instead of using 70 parts by weight of Epicoat 815 as the epoxy resin (B), Epicoat 828 was used.
[(Trade name), bisphenol A type epoxy resin (epoxy equivalent: about 190), manufactured by Yuka Shell Epoxy Co.] 50 parts by weight and Epicoat 1001 [(trade name), bisphenol A type epoxy resin (epoxy equivalent: about 480) In the same manner as in Example 10 except that 20 parts by weight of Yuka Shell Epoxy Co., Ltd. was used, and the amount of DICY used and the amount of the organic solvent for adjusting viscosity were adjusted according to the change in the number of epoxy groups. To produce a thermosetting pressure-sensitive adhesive composition. The composition, basic physical properties, and measurement results of the adhesive properties of the obtained thermosetting pressure-sensitive adhesive composition are shown in Table 2 and FIG.

Example 16 In Example 10, instead of using 75 parts by weight of the acrylic copolymer (A) solution of Example 1 and 70 parts by weight of Epicoat 815 as the epoxy resin (B), the acrylic copolymer of Example 1 was used. (A) 50 parts by weight of a solution, 55 parts by weight of Epicoat 828 as an epoxy resin (B) and Epicoat 10
01 Using 25 parts by weight, a thermosetting pressure-sensitive adhesive composition was prepared in the same manner as in Example 10 except that the amount of DICY used and the amount of the organic solvent for adjusting the viscosity were adjusted according to the change in the number of epoxy groups. Was manufactured. The composition, basic physical properties, and measurement results of the adhesive properties of the obtained thermosetting pressure-sensitive adhesive composition are shown in Table 2 and FIG.

Examples 20, 30, 40, 50 and Comparative Examples 10, 20, 30 In Example 10, instead of using the acrylic copolymer of Example 1, the acrylic copolymers of Examples 2 to 5 and Comparative Examples 1 to 3 were used. A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the copolymer was used and the amount of DICY used was adjusted according to the change in the number of epoxy groups accompanying the copolymer. The composition, basic physical properties, and measurement results of the adhesive properties of the obtained thermosetting pressure-sensitive adhesive composition are shown in Table 2 and FIG.

Examples 21, 31, 41, 51 and Comparative Examples 11, 21, 31 In Example 11, instead of using the acrylic copolymer of Example 1, the acrylic copolymers of Examples 2 to 5 and Comparative Examples 1 to 3 were used. A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the copolymer was used and the amount of DICY used was adjusted according to the change in the number of epoxy groups accompanying the copolymer. The composition, basic physical properties, and measurement results of the adhesive properties of the obtained thermosetting pressure-sensitive adhesive composition are shown in Table 2 and FIG.

Examples 22 to 24 and 26 In Examples 11 to 14 and 16, instead of using the acryl-based copolymer of Example 1, the acrylic copolymer of Example 2 was used, and the number of epoxy groups accompanying the acryl-based copolymer of Example 2 was used. DI according to the change of
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of CY used was adjusted. FIG. 1 shows the change in the room temperature adhesive force with respect to the blending ratio of the acrylic copolymer of Example 2 and the epoxy resin (B) in the obtained thermosetting pressure-sensitive adhesive composition.

Examples 32 to 34 and 36 In Examples 11 to 14 and 16, instead of using the acrylic copolymer of Example 1, the acrylic copolymer of Example 3 was used, and the number of epoxy groups accompanying the acrylic copolymer of Example 3 was used. According to the change of
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used was adjusted. FIG. 1 shows the change in the room temperature adhesive force with respect to the blending ratio of the acrylic copolymer of Example 3 and the epoxy resin (B) in the obtained thermosetting pressure-sensitive adhesive composition.

Examples 42 to 44 and 46 In Examples 11 to 14 and 16, instead of using the acrylic copolymer of Example 1, the acrylic copolymer of Example 4 was used, and the number of epoxy groups accompanying the same was used. According to the change of
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used was adjusted. FIG. 1 shows the change in the room temperature adhesive force with respect to the mixing ratio of the acrylic copolymer of Example 4 and the epoxy resin (B) in the obtained thermosetting pressure-sensitive adhesive composition.

Examples 52 to 54 and 56 In Examples 11 to 14, and 16, instead of using the acrylic copolymer of Example 1, the acrylic copolymer of Example 5 was used, and the number of epoxy groups accompanying the acrylic copolymer of Example 5 was used. According to the change of
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used was adjusted. FIG. 1 shows the change in the room temperature adhesive force with respect to the blending ratio of the acrylic copolymer of Example 5 and the epoxy resin (B) in the obtained thermosetting pressure-sensitive adhesive composition.

Comparative Examples 12 to 14, 16 In Examples 11 to 14, 16, instead of using the acrylic copolymer of Example 1, the acrylic copolymer of Comparative Example 1 was used, and the number of epoxy groups accompanying the acrylic copolymer was used. According to the change of
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used was adjusted. FIG. 1 shows the change in the room temperature adhesive force with respect to the mixing ratio of the acrylic copolymer of Comparative Example 1 and the epoxy resin (B) in the obtained thermosetting pressure-sensitive adhesive composition.

Comparative Examples 22 to 24 and 26 In Examples 11 to 14 and 16, instead of using the acrylic copolymer of Example 1, the acrylic copolymer of Comparative Example 2 was used, and the number of epoxy groups accompanying the acrylic copolymer was used. According to the change of
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used was adjusted. FIG. 1 shows the change in the room-temperature adhesive force with respect to the blending ratio of the acrylic copolymer of Comparative Example 2 and the epoxy resin (B) in the obtained thermosetting pressure-sensitive adhesive composition.

Comparative Examples 32-34 and 36 In Examples 11-14 and 16, instead of using the acrylic copolymer of Example 1, the acrylic copolymer of Comparative Example 3 was used, and the number of epoxy groups accompanying the acrylic copolymer was used. According to the change of
A thermosetting pressure-sensitive adhesive composition was produced in the same manner except that the amount of DICY used was adjusted. FIG. 1 shows the change in the room temperature adhesive force with respect to the blending ratio of the acrylic copolymer of Comparative Example 3 and the epoxy resin (B) in the obtained thermosetting pressure-sensitive adhesive composition.

[Effects of the Invention] As is clear from FIGS. 1 (1) and 1 (2),
Examples 1 to 5 of the acrylic copolymer (A) of the present invention
The thermosetting pressure-sensitive adhesive composition using the acrylic copolymer of (1) has an extremely excellent room-temperature adhesive force such as 5 kg / cm ² or more in a wide range of mixing ratio with the epoxy resin (B). An agent layer can be formed.

On the other hand, the thermosetting pressure-sensitive adhesive composition using the acrylic copolymer of Comparative Example 1 in which the acrylic acid or methacrylic acid ester monomer having a hydroxyl group is not copolymerized has a mixing ratio of the epoxy resin (B). In the range where the amount of the epoxy resin (B) is small, the sufficient room temperature adhesive force cannot always be exerted, and the epoxy resin (B) has an epoxy group. In the thermosetting pressure-sensitive adhesive composition using the acrylic copolymer of Comparative Example 2 in which no monomer was copolymerized, the mixing ratio of the epoxy resin (B) was 20 to 100% by weight of the resin component. 6
In a medium range such as 0% by weight, excellent room-temperature adhesive strength can be exhibited, but sufficient room-temperature adhesive strength cannot be exhibited in a range where the blending ratio is larger or smaller.

Furthermore, the thermosetting pressure-sensitive adhesive composition using the acrylic copolymer of Comparative Example 3 having a low molecular weight that deviates from the molecular weight requirement of the present invention is the same as the acrylic copolymer of Comparative Example 1, In the range where the mixing ratio of the epoxy resin (B) is large, relatively good room-temperature adhesive strength is exhibited. However, in the range where the mixing ratio of the epoxy resin (B) is small, sufficient room-temperature adhesion cannot be exhibited. is there.

[Brief description of the drawings]

FIGS. 1 (1) and 1 (2) show a thermosetting pressure-sensitive adhesive composition comprising various acrylic copolymers (A), epoxy resins (B) and epoxy resin curing agents (C). 3 is a graph showing a relationship between a composition ratio of an acrylic copolymer (A) / epoxy resin (B) and an adhesive force at room temperature in a used pressure-sensitive adhesive layer. 1 ... Use of acrylic copolymer of Example 1 2 ... Use of acrylic copolymer of Example 2 3 ... Use of acrylic copolymer of Example 3 4 ... Acrylic copolymer of Example 4 Incorporation 5: Use of acrylic copolymer of Example 5 1 ': Use of acrylic copolymer of Comparative Example 1 2': Use of acrylic copolymer of Comparative Example 3 3 ': Comparative Example 3 Use of acrylic copolymer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ identification code FI C08F 220: 28) (58) Investigated field (Int.Cl. ⁶ , DB name) C09J 163/00-163/10 C09J 133 / 04-133/12 C08F 220/10-220/18 C08F 224/00 C08F 220/28

Claims (1)

(57) [Claims] An acrylic copolymer (A) used in a thermosetting pressure-sensitive adhesive composition comprising an acrylic copolymer (A), an epoxy resin (B) and an epoxy resin curing agent (C). The copolymer (A) is composed of the following monomers a to
e, a. 5 to 40% by weight of a monomer having an epoxy group, b. 5 to 20% by weight of an acrylic acid or methacrylic acid ester monomer having a hydroxyl group represented by the following general formula: c. 50 to 90% by weight of acrylic acid or methacrylic acid ester monomer represented by the following general formula, d. a monomer having at least one functional group in addition to the radically polymerizable unsaturated group, wherein 0 to 15% by weight of a monomer other than the monomers a and b, and e. 0 to 50% by weight of a comonomer other than the monomers a to d, which is copolymerizable with the monomers a to d (provided that the total of the monomers a to e is 100% by weight) An acrylic copolymer for a thermosetting pressure-sensitive adhesive composition, which is an acrylic copolymer obtained by copolymerization and having a number average molecular weight of 50,000 or more.