JP2649473B2 - Epoxy resin adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin adhesive composition having improved epoxy resin adhesiveness.

[0002]

2. Description of the Related Art Epoxy resins have been particularly actively modified, and the range of application thereof has been expanded. Epoxy resin has excellent electrical properties, adhesive properties, thermal properties, etc., but is generally brittle, not only has the problem of easily generating cracks due to stress distortion during curing and use, heat and mechanical shock, Further improvement in adhesiveness is desired. To solve this problem, the use of hardeners with long chain aliphatic groups or rubbery properties,
The adhesiveness of the epoxy compound is improved by adding a compound having elastomeric properties, adding a plasticizer such as asphalt substance, glycols, etc., and introducing a molecular group exhibiting rubber elasticity into the epoxy compound itself. Have been done.

[0003]

However, these substances are not sufficiently compatible with the epoxy resin, so that sufficient compounding properties cannot be obtained, and the properties such as excellent heat resistance of the epoxy resin are impaired. Problems such as extremely high cost have occurred, and there are problems such as not being able to exhibit a sufficient effect and being unable to be used in terms of cost. The present invention has been made in view of these problems, and an object of the present invention is to provide an epoxy resin adhesive composition that provides improved adhesiveness without reducing characteristics such as heat resistance of the epoxy resin.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that an epoxy resin and an epoxy resin modified with a polybutadiene / acrylonitrile copolymer having carboxy groups at both ends are available. A phenolic hydroxyl group-containing aromatic polyamide oligomer having an aminoaryl group at each end and a polybutadiene / acrylonitrile copolymer having a carboxyl group at each end, The present inventors have found that by incorporating an epoxy resin modified with a block copolymer formed from the above, it is possible to significantly improve the adhesiveness of the epoxy resin without reducing the properties of the epoxy resin and its cured product, and completed the present invention. did. That is, by introducing the epoxy resin modified with the block copolymer into the epoxy resin adhesive composition, the polybutadiene / polybutadiene formed by curing the epoxy resin adhesive composition and then phase-separating it.
It is presumed that the acrylonitrile copolymer particles are more finely and uniformly dispersed, thereby improving the adhesiveness.

[0005] The epoxy resin used in the present invention is not particularly limited. Examples thereof include glycidyl ethers, glycidyl esters, glycidylamines, linear aliphatic epoxides, alicyclic epoxides, and hydantoin type epoxies. And the like. The glycidyl ethers include, for example, glycidyl ether of bisphenol, polyglycidyl ether of phenol novolak, glycidyl ether of alkylene glycol or polyalkylene glycol, and the like. Examples of the glycidyl ether of bisphenol include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrachlorobisphenol A, tetrabromobisphenol A, and the like. Examples of diglycidyl ethers of dihydric phenols are polyglycidyl ethers of phenol novolak, for example, polyglycidyl ethers of novolak resins such as phenol novolak, cresol novolak, and brominated phenol novolak are aralkylene glycol or polyalkylene glycol. Examples of the diglycidyl ether include polyethylene glycol and polypropylene glycol. Include diglycidyl ethers of glycols such as butanediol. The glycidyl esters include, for example, glycidyl esters of hexahydrophthalic acid and glycidyl esters of dimer acid, and the glycidylamines include, for example, triglycidylaminodiphenylmethane, triglycidylaminophenol, and triglycidyl. And isocyanurate. Furthermore, examples of the linear aliphatic epoxides include epoxidized polybutadiene and epoxidized soybean oil, and examples of the alicyclic epoxides include:
Examples include 3,4-epoxy-6-methylcyclohexylmethyl carboxylate, 3,4-epoxycyclohexylmethyl carboxylate, and hydrogenated bisphenol epoxy. Hydantoin type epoxies include diglycidyl hydantoin, glycidylglycidoxyalkylhydantoin, and the like. These epoxy resins may be used alone or in combination of two or more. Further, in the epoxy resin adhesive composition of the present invention, the above-mentioned glycidyl ether type epoxy resin of a dihydric phenol, which is easily modified, has low viscosity, and is excellent in handleability, is preferably used.

As the epoxy resin curing agent used in the present invention, for example, bis (4-aminophenyl) sulfone, bis (4-aminophenyl) methane, 1,5-diaminonaphthalene, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 2,6-dichloro-
Aromatic amine curing agents such as 1,4-benzenediamine, 1,3-di (p-aminophenyl) propane, m-xylenediamine, ethylenediamine, diethylenetriamine, tetraethylenepentamine, diethylaminopropylamine, hexamethylenediamine, Aliphatic amine compounds such as mensendiamine, isophoronediamine, bis (4-amino-3-methyldicyclohexyl) methane, polymethylenediamine, and polyetherdiamine;
Polyaminoamide compounds, aliphatic acid anhydrides such as dodecyl succinic anhydride, polyadipic anhydride, polyazeleic anhydride, alicyclic acid anhydrides such as hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and phthalic anhydride Acid, trimellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis trimellitate,
Aromatic anhydrides such as glycerol tristrimellitate, phenolic compounds and phenolic resins, amino resins,
Urea resins, melamine resins, dihydrazines, imidazoles, Lewis acids, Bronsted acid salts, polymercaptons, isocyanates, blocked isocyanates, but include, but are not limited to, the present invention. Preferred curing agents for use as epoxy resin adhesive compositions include dicyandiamide and 1-
A guanidine derivative represented by (o-tolyl) biguanide can be preferably used.

Further, in the present invention, a reaction accelerator can be used for the reaction between the epoxy resin and the epoxy resin curing agent. Examples of such a reaction accelerator include phosphorus compounds such as triphenylphosphine and tertiary amine compounds such as triethylamine, tetraethanolamine, 1,8-diaza-bicyclo [5,4,0] -7-undecene ( DBU), boron compounds such as N, N-dimethylbenzylamine, 1,1,3,3-tetramethylguanidine, 2-ethyl-4-methylimidazole, N-methylpiperazine, and the like, for example, 1,8-diaza-bicyclo [5,4,0] -7-undecenium tetraphenyl borate and the like are used. The polybutadiene / acrylonitrile copolymer having a carboxyl group at both ends used in the present invention is commercially available as Hycar CTBN from BF Goodrich and can be used. The above-mentioned epoxy resin modified with a polybutadiene / acrylonitrile copolymer having a carboxyl group at both ends can be easily prepared by heating and mixing the two components in a solvent or without a solvent to react the carboxyl group and the epoxide group. Can be manufactured. In this reaction, a reaction accelerator represented by tetramethylammonium bromide may be used. This reaction is generally performed at a temperature of room temperature to 200 ° C. with stirring for several minutes to about 24 hours.

The phenolic hydroxyl group-containing aromatic polyamide oligomer having aminoaryl groups at both ends used in the present invention is synthesized by condensation polymerization of an aromatic diamine component and an aromatic dicarboxylic acid component. In the present invention, by mixing an aromatic diamine or aromatic dicarboxylic acid having a hydroxyl group into at least these aromatic diamine components or aromatic dicarboxylic acid components,
A phenolic hydroxyl group-containing aromatic polyamide oligomer can be produced. In addition, conversion of both ends of the oligomer to an aminoaryl group can be easily achieved by subjecting the aromatic diamine component to a polycondensation reaction in excess of the aromatic dicarboxylic acid component. The blocking of the phenolic hydroxyl group-containing aromatic polyamide having aminoaryl groups at both ends and the polybutadiene / acrylonitrile copolymer having carboxyl groups at both ends synthesized in the same manner as described above is carried out in the same manner as in the above-mentioned condensation polymerization. Can be synthesized by This polycondensation reaction can be performed by a conventionally known method. That is, the above-mentioned direct dehydration polycondensation polymerization method between a carboxyl group and an amino group, a polymerization method in which a carboxyl group is acid chlorided with thionyl chloride or the like, and then reacted with an amino group, condensation represented by phosphite and pyridine, etc. Polymerization in the presence of a polymerization catalyst is exemplified.In the present invention, these methods are not particularly limited, but a synthesis method using a polycondensation catalyst using a phosphite and pyridine that can be polymerized under relatively mild conditions. preferable.

The aromatic diamine used for producing the phenolic hydroxyl group-containing aromatic polyamide oligomer of the present invention includes m-phenylenediamine, p-phenylenediamine, metatolylenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4 '
-Diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylthioether,
3,3'-dimethyl-4,4'-diaminodiphenylthioether, 3,3'-diethoxy-4,4'-diaminodiphenylthioether, 3,3'-diaminodiphenylthioether, 4,4'-diaminobenzophenone, , 3'-dimethyl-4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,
4'-diaminodiphenylmethane, 3,3'-dimethoxy-4,4'-diaminodiphenylmethane, 2,2'-
Bis (3-aminophenyl) propane, 2,2'-bis (4-aminophenyl) propane, 4,4'-diaminodiphenylsulfoxide, 4,4'-diaminodiphenylsulfone, benzidine, 3,3'-dimethyl bench Gin, 3,3'-dimethoxybenzidine, 3,3'-diaminobiphenyl, p-xylylenediamine, m-xylylenediamine, m-xylylenediamine, etc., which may be used alone or in combination. Can be. Examples of the carboxylic acid used for producing the phenolic hydroxyl group-containing aromatic polyamide oligomer of the present invention include phthalic acid, isophthalic acid, terephthalic acid, 4,4'-biphenyldicarboxylic acid, and 3,3'-methylene dibenzoic acid. 4,
4'-methylene dibenzoic acid, 4,4'-oxydibenzoic acid, 4,4'-thiodibenzoic acid, 3,3'-carbonyldibenzoic acid, 4,4'-carbonyldibenzoic acid, 4,
4'-sulfonyl dibenzoic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-
Examples include, but are not limited to, naphthalenedicarboxylic acid.

Further, the hydroxyl-containing aromatic dicarboxylic acid or hydroxyl-containing aromatic diamine used for introducing a phenolic hydroxyl group into the aromatic polyamide oligomer of the present invention includes 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, and the like. 2-hydroxyphthalic acid, 3-hydroxyphthalic acid, 2-hydroxyterephthalic acid, 3,
3'-dihydroxy-4,4'-dianiline, 2,2-
Bis (3'-amino-4-hydroxyphenyl) propane, 2,4-dihydroxy-1,5-diaminobenzene, 5-hydroxy-1,3-diaminobenzene and the like can be used. However, the present invention is not limited to these. The phenolic hydroxyl group-containing aromatic polyamide-polybutadiene produced by the method described above /
It is necessary to modify the epoxy resin with an acrylonitrile block copolymer. It is preferable that this copolymer has high compatibility with an epoxy resin and solvent solubility. The method of modifying an epoxy resin with the phenolic hydroxyl group-containing aromatic polyamide-polybutadiene / acrylonitrile block copolymer is a method in which the epoxy resin and the copolymer are modified without solvent or in a solvent represented by tetrahydrofuran. It can be modified by reacting a hydroxyl group in the polymer with an epoxide group of the epoxy resin.
In this reaction, a reaction accelerator represented by triphenylphosphine can be used. This reaction can be easily carried out in a temperature range from room temperature to about 200 ° C. with stirring for about several minutes to about 24 hours.

In the epoxy resin adhesive composition of the present invention, a polybutadiene / acrylonitrile copolymer-modified epoxy resin having carboxy groups at both ends is added in an amount of 1 to 80% by weight based on all epoxy resins in the epoxy resin adhesive composition of the present invention. %, A more appropriate adhesive property can be obtained. Further, the epoxy resin modified with the phenolic hydroxyl group-containing aromatic polyamide-polybutadiene / acrylonitrile block copolymer has a content of 0.1 to 20% by weight based on the total epoxy resin in the epoxy resin adhesive composition of the present invention. Shows significantly improved adhesive properties. Addition of the modified epoxy resin more than this is not preferable because it significantly increases the viscosity of the epoxy resin adhesive composition and causes processing problems.

The epoxy resin adhesive composition of the present invention can be prepared by the above-mentioned method, and other additives can be further added to the adhesive composition as required. For example, natural waxes, synthetic waxes and metal salts of long-chain aliphatic acids, acid amides, esters, release agents such as paraffins, silicone rubber, nitrile rubber, butadiene rubber, stress relievers such as polysiloxane, Chlorinated paraffin, bromotoluene, hexabromobenzene,
Flame retardants such as antimony trioxide, silane coupling agents, titanate coupling agents, coupling agents such as aluminum coupling agents, fused silica, crystalline silica, glass flakes, glass beads, glass balloons, talc, alumina , Calcium silicate, calcium carbonate, barium sulfate, magnesia, silicon nitride, boron nitride, ferrite, rare earth cobalt, gold, silver, nickel,
Metal powders such as copper, lead, iron powder, iron oxide, iron sand, inorganic fillers such as graphite and carbon or conductive particles, coloring agents such as dyes and pigments, oxidation stabilizers, light stabilizers, moisture resistance improvers, A thixotropy-imparting agent, a diluent, an antifoaming agent, other resins and the like can also be blended.

The epoxy resin adhesive composition of the present invention includes the epoxy resin adhesive composition before and after heat curing. This heat curing is generally performed by heating at 250 ° C. or lower for several hours, but there is no limitation in the present invention. Further, the epoxy resin adhesive composition of the present invention also includes a formed body obtained by curing by heating.

[0014]

EXAMPLES Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited to these examples. Synthesis Example 1 Phenolic hydroxyl group-containing aromatic polyamide-polybutadiene / acrylonitrile block copolymer (14 mol% of phenolic hydroxyl groups contained in aromatic polyamide portion) 19.93 g (120 mmol) of isophthalic acid, 3,
30.63 g (153 mmol) of 4'-oxydianiline, 3.64 g (20 mmol) of 5-hydroxyisophthalic acid, 3.9 g of lithium chloride, calcium chloride 1
2.1 g, 240 ml of N-methyl-2-pyrrolidone and 54 ml of pyridine were placed in a 1-liter four-necked round-bottomed flask and dissolved by stirring.
g was added and reacted at 90 ° C. for 4 hours to produce a phenolic hydroxyl group-containing aromatic polyamide oligomer. Polybutadiene / acrylonitrile copolymers with carboxyl groups at both ends (Hycar CTBN, BF Goodr
Made by ich. The acrylonitrile component contained in the polybutadiene acrylonitrile part is 17 mol% and the molecular weight is about 36.
00) A solution obtained by dissolving 48 g in 240 ml of pyridine was added, and the reaction was further carried out for 4 hours. After cooling to room temperature, the reaction solution was poured into 20 liters of methanol, and the polybutadiene / acrylonitrile copolymer part used in the present invention was used. Of an aromatic polyamide-polybutadiene / acrylonitrile block copolymer containing about 14 mol% of a phenolic hydroxyl group having a content of 50 wt%. The precipitated polymer was further purified by washing with methanol and refluxing methanol. The intrinsic viscosity of this polymer is 0.85 dl / g
(Dimethylacetamide, 30 ° C.). Was measured infrared spectrum by diffusion reflection method polymer powder, an amide carbonyl group to 1674cm ^-1, 2856
The absorption based on C-H bonds of the butadiene part in -2975cm ^-1, revealed absorption based on nitrile group in 2245 cm ^-1.

Synthesis Example 2 Epoxy resin (Epicoat 828, average molecular weight: 38)
0, epoxy equivalent: 190 ± 5, manufactured by Yuka Shell Co., Ltd.)
A polybutadiene / acrylonitrile copolymer having carboxyl groups at both ends in 100 g (Hycar CTBN, BF G
Made by oodrich. The acrylonitrile component contained in the polybutadiene / acrylonitrile copolymer is 27 mol%, the molecular weight is about 3400), 120 g, and 1 g of a reaction accelerator, tetramethylammonum bromide, are added, and mixed and reacted at 130 ° C. for about 70 minutes. An epoxy resin composition containing 54.5% by weight of this polybutadiene / acrylonitrile copolymer-modified epoxy resin was prepared.

Synthesis Example 3 The phenolic hydroxyl group obtained in Synthesis Example 1 contains about 14 mol%
6 g of aromatic polyamide / polybutadiene / acrylonitrile block copolymer contained, epoxy resin 100
g, 0.6 g of triphenylphosphine as a reaction accelerator
Was dissolved in 120 g of tetrahydrofuran and reacted under reflux for 24 hours. This was vacuum-dried to obtain an epoxy resin composition containing 5.7% by weight of an epoxy resin modified with an aromatic polyamide / polybutadiene / acrylonitrile block copolymer. 1 mg of this product is
To a solution dissolved in 0 ml of pyridine, a color indicator for phenolic hydroxyl group [1 g of anhydrous iron (III) chloride was dissolved in 100 ml of chloroform, and 8 ml of pyridine was added.
The precipitate was filtered and a red solution was prepared), and several drops were added thereto and stirred, but no discoloration was observed.In this resin, all phenolic hydroxyl groups reacted with glycidyl groups, and unreacted phenol was reacted. It was confirmed that no residue was contained.

Comparative Example 1 2.75 g of the modified epoxy resin composition obtained in Synthesis Example 2, an epoxy resin (Epicoat 828, average molecular weight: 380,
Epoxy equivalent: 190 ± 5, manufactured by Yuka Shell Co.) 7.25
g and further the curing agent 1- (o-tolyl) biguanide 5.87
g, and 0.7 g of 3- (3,4-dichlorophenyl) -1,1-dimethylurea, which is a reaction accelerator, was mixed and stirred, and a polybutadiene / acrylonitrile copolymer-modified epoxy resin containing 15% by weight was used for comparison. A sample of the epoxy resin adhesive composition was obtained.

Example 1 Contains 2.75 g of the modified epoxy resin composition obtained in Synthesis Example 2, 4.60 g of the epoxy resin, and the modified epoxy resin of the aromatic polyamide / polybutadiene / acrylonitrile block copolymer obtained in Synthesis Example 3. 2.65 g of the obtained epoxy resin composition, 5.87 g of a curing agent 1- (o-tolyl) biguanide, and 0.7 g of 3- (3,4-dichlorophenyl) -1,1-dimethylurea as a reaction accelerator. Evenly mixed, the polybutadiene / acrylonitrile copolymer-modified epoxy resin was 15% by weight, and the aromatic polyamide /
A sample of the epoxy resin adhesive composition of the present invention containing 1.5% by weight of a polybutadiene / acrylonitrile block copolymer-modified epoxy resin was obtained.

Example 2 An epoxy resin composition according to Example 1 containing the epoxy resin from 4.60 to 1.95 g and the aromatic polyamide / polybutadiene / acrylonitrile block copolymer-modified epoxy resin obtained in Synthesis Example 3. 2.65 g of thing
In the same manner except that the weight of the polybutadiene / acrylonitrile copolymer-modified epoxy resin was changed to 15% by weight, and that of the aromatic polyamide / polybutadiene / acrylonitrile block copolymer-modified epoxy resin was changed to 3.30 g.
A sample of the epoxy resin adhesive composition of the present invention, which contained the same by weight, was obtained.

Example 3 The same procedure as in Example 1 except that the amount of the epoxy resin was changed from 4.60 g to 0 g and the modified epoxy resin composition obtained in Synthesis Example 3 was changed from 2.65 g to 7.95 g. In the method, a sample of the epoxy resin adhesive composition of the present invention containing 15% by weight of a polybutadiene / acrylonitrile copolymer-modified epoxy resin and 4.5% by weight of an aromatic polyamide / polybutadiene / acrylonitrile block copolymer-modified epoxy resin was prepared. Obtained.

The epoxy resin adhesive compositions of Comparative Example 1 and Examples 1 to 3 were applied to a mild steel plate (SS-4, manufactured by Nippon Steel Corporation).
Is polished with a # 240 sand parper, applied to a surface washed with acetone, and then heated and cured at 220 ° C. for 1 hour, and the cured product is measured for bond energy and tensile shear strength as described below. Was evaluated. Table 1 summarizes the obtained results. Measurement of Fracture Energy: According to ASTM D3433, a 0.4 mm-wide cantilevered specimen of the mild steel sheet was used.
A 2 mm adhesive layer is formed by the above-described method, and
It was determined from the splitting test of the adhesive layer. The measurement was performed at a crosshead speed of 0.5 mm / min using an Instron type tensile tester (AGS-100A, manufactured by Shimadzu Corporation). Measurement of tensile shear strength: ASTM D1002-61
The tensile shear strength was determined for a test piece having an adhesive layer formed on the 1.6 mm-thick mild steel sheet by the method described above. The measurement was performed using an Instron tensile tester (AGS-
100A (manufactured by Shimadzu Corporation) at a crosshead speed of 50 mm / min.

[0022]

[Table 1] Example: Block copolymer of copolymer ^a) polymer ^b) the content of the fracture energy tensile strength content ^{(J / m 2) (MN} / m 2) (wt%) (wt%) ─────────────────比較 Comparative Example 1 15-230 28 Example 1 15 1.5 990 36 Example 2 15 3.0 1040 37 Example 3 15 4. A) polybutadiene having carboxyl groups at both ends /
Acrylonitrile copolymer modified epoxy resin b) Aromatic polyamide / polybutadiene / acrylonitrile block copolymer modified epoxy resin shown in Synthesis Example 3

The epoxy resin adhesive composition of the present invention provides an epoxy resin composition having improved adhesion.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-21450 (JP, A) JP-A-60-141873 (JP, A) JP-A-4-31716 (JP, A) JP-A-4- 328116 (JP, A) JP-A-58-147416 (JP, A) JP-A-61-283627 (JP, A)

Claims (4)

(57) [Claims] 1. An epoxy resin adhesive composition mainly comprising an epoxy resin, an epoxy resin curing agent, and an epoxy resin modified with a polybutadiene / acrylonitrile copolymer having carboxyl groups at both ends, wherein the epoxy resin adhesive composition is A modified epoxy resin modified with a block copolymer formed from a phenolic hydroxyl group-containing aromatic polyamide oligomer having an aminoaryl group at both terminal groups and a polybutadiene / acrylonitrile copolymer having a carboxyl group at both terminals. An epoxy resin adhesive composition characterized by being contained. 2. The epoxy resin adhesive composition according to claim 1, wherein the epoxy resin is a glycidyl ether type epoxy resin of a dihydric phenol. 3. The epoxy resin adhesive composition according to claim 1, wherein the curing agent is a guanidine derivative. 4. An epoxy resin modified with a polybutadiene / acrylonitrile copolymer having carboxyl groups at both ends in an amount of 1 to 80% by weight and an aminoaryl group in all epoxy resins in the epoxy resin adhesive composition. A modified epoxy resin modified with a block copolymer formed from a phenolic hydroxyl group-containing aromatic polyamide oligomer having a terminal group and a polybutadiene / acrylonitrile copolymer having a carboxyl group at both ends is 0.1%.
The epoxy resin adhesive composition according to claim 1, wherein the composition comprises from 20 to 20% by weight.