JPH0587106B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a heat-resistant adhesive composition comprising a heat-resistant soluble polymer and an epoxy compound. BACKGROUND ART Polyimide adhesives have been known as heat-resistant adhesives. Whether these polyimide adhesives are used for varnishes or films, water is generated during the imidization process, which tends to cause voids, which leads to a decrease in adhesive strength. Therefore, careful temperature control is required during the imidization process. In addition, in the bonding process, the adhesive flow is poor, so we use high temperatures of over 350℃ and 60Kgf/
It was believed that high pressure of cm ² or higher was required. Furthermore, polyimide resin has low compatibility with epoxy resin, so there are few examples of using both together.
The only adhesive that is a mixture of soluble polyimide and epoxy resin is adhesive for flexible printed wiring boards (Japanese Patent Application Laid-open No. 130666/1983). Problems to be Solved by the Invention The purpose of the present invention is to take advantage of the excellent heat resistance of polyimide and polyester, and use these together with an epoxy compound to bond various materials at a lower temperature and pressure than conventional adhesives. The aim is to develop an adhesive that can be bonded to the skin and exhibit sufficient adhesion ability even at high temperatures. Means for Solving the Problems As a result of intensive studies to achieve the above object, the present invention focuses on the solvent solubility of polyester and polyimide using specific compounds, and furthermore, by mixing an epoxy compound, adhesive strength is improved. We have developed a heat-resistant adhesive that has excellent properties and is liquid, making it easy to work with. . That is, the present invention provides 20 to 48 parts by weight of a soluble polyester resin obtained by reacting an aromatic diol represented by the formula with at least one of aromatic dicarboxylic acids and unsaturated dicarboxylic acids;

[Formula] (However, in the formula, R represents H, CH ₃ or C ₂ H _5. ) An aromatic diamine represented by the formula and H ₂ N-
Soluble polyimide resin obtained by reacting an aliphatic diamine represented by C _o H _2o -NH ₂ (n = an integer of 2 to 8) with an aromatic tetracarboxylic acid.
12-36 parts by weight, formula

[Formula] (In the formula, R' represents H, CH ₃ or C ₂ H _5. ) 35 to 50 parts by weight, preferably 40 to 50 parts by weight of an epoxy compound having two or more epoxy groups in one molecule A heat-resistant adhesive composition comprising: and a curing agent thereof. In the present invention, polyester resin and polyimide resin are used to impart heat resistance. Polyester resin has excellent adhesive strength especially at around 200℃,
Polyimide resin has excellent adhesive strength at around 100℃. The epoxy compound serves as a binder for the polyester resin and polyimide resin, and supplements the flowability and adhesive strength that the polyimide resin and polyester resin lack. The soluble polyester resin (component A) used in the present invention contains 9,9-bis(4-hydroxyphenyl) as a diol represented by the above formula.
Fluorene, 9,9-bis(3-methyl-4-hydroxyphenyl)fluorene, 9,9-bis(3-ethyl-4-hydroxyphenyl)fluorene, etc. are used. As the aromatic dicarboxylic acids to be reacted with the diol component, any general aromatic acid dichloride can be used, but it is preferable to use terephthalic acid dichloride, isophthalic acid dichloride, etc. In addition, aromatic dicarboxylic acids are 1
There is no problem even if it is a species or two species. Unsaturated dicarboxylic acids mean dicarboxylic acids having a carbon-carbon double bond or a carbon-carbon triple bond in the molecule, such as fumaric acid chloride, preferably with the formula ClOC6-CnH
One expressed as n-COCl (n=an integer of 2 to 8) is used. The number of unsaturated dicarboxylic acids may be one or two. The purpose of using unsaturated carboxylic acids is to improve the flow of the adhesive during bonding. Either aromatic dicarboxylic acids or unsaturated carboxylic acids may be used, but
When used in combination, it exhibits high heat resistance while maintaining solvent solubility and good flowability. Specifically, for example, the molar ratio of terephthalic acid chloride and isophthalic acid or fumaric acid chloride is 1:9 to 10:0, preferably 1:9 to 10:0, for good flow and high heat resistance required as a heat-resistant adhesive. 5:
A ratio of 5 to 10:0 is desirable. Polyimide resin used in the present invention (component B)
9,9-bis(4-aminophenyl)fluorene, 9,9-bis(3-methyl-4-aminophenyl)fluorene, 9,9-bis(3-ethyl-
4-aminophenyl) fluorene etc. are used as raw materials. Furthermore, the aliphatic diamine used to obtain the polyimide resin has the formula H ₂ N−C _o H _2o −
It is an aliphatic diamine represented by NH ₂ (n=an integer of 2 to 8). When n=2 to 8, good solvent solubility and sufficient strength when formed into a film can be obtained. Preferred are ethylene diamine, propylene diamine, butylene diamine, pentamethylene diamine, hexamethylene diamine, octamethylene diamine, and the like. Furthermore, the number of aliphatic diamines may be one or two or more. The molar ratio of the aliphatic diamine to the aromatic diamine represented by the formula is 1:9 to 9:1, preferably 5:5 to 9:1, for good flow and high heat resistance necessary for a heat-resistant adhesive. It is desirable to set it to 1. The aromatic tetracarboxylic acids to be reacted with the diamine component mentioned above mean aromatic tetracarboxylic acids in which two sets of mutually adjacent carboxyl groups are directly bonded to an aromatic ring, and specifically, pyromellitic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',
4,4'-biphenyltetracarboxylic dianhydride,
Bis(2,3-dicarboxyphenyl)sulfone dianhydride, 2,2-bis(3,4-biscarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride Examples include. Moreover, these aromatic tetracarboxylic acids may be used alone or in combination of two or more. The epoxy compounds used in the present invention include:
2,2-bis(p-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 1,1,2,2-tetrakis(p-hydroxyphenyl) ethane,
4,4-dihydroxydiphenyl, resorcinol,
Glycidyl ethers of aromatic diphenols such as catechol and hydroquinone, glycidyl ethers such as phenol novolak, cresol linovolak, and vinylcyclohexene diepoxide,
(3,4'-epoxycyclohexylmethyl)-3,
4-Epoxychlorohexanecarboxylate, (3,
4'-epoxy-6'-methyl-cyclohexylmethyl)-3,4-epoxy-6-methylcyclohexanecarboxylate, 3-(3',4'-epoxycyclohexyl)-2,4-dioxaspiro(5,
5) Alicyclic epoxy resins such as -8,9-epoxyundecane, 3-(glycidyloxyethoxyethyl)-2,4-dioxaspiro(5,5)-8,9-epoxyundecane, and triglycidyl isocyanurate, 5 , N,N-diglycidylic acid derivatives of 5-dimethylhydantoin, and heterocyclic epoxy resins, which can be used alone or as a mixture of two or more thereof. Furthermore, known curing agents for these epoxy compounds can be used. Specifically, it is as follows. Dicyandiamide, organic acid anhydrides, aliphatic polyamines, aromatic polyamines, amines, imidazole, etc. can be used alone or in a mixed system of two or more. Further, the amount of the curing agent is preferably 0.5 parts by weight or less per 100 parts by weight of the soluble polyester resin, soluble polyimide resin, and epoxy compound. If the amount is more than 0.5 part by weight, the adhesive strength in high temperature areas will decrease. Although sufficient adhesion can be obtained without a curing agent, it takes a long time for adhesion. The blending ratio of the adhesive of the present invention is 48 to 20 parts by weight of the soluble polyester resin, 36 to 12 parts by weight of the soluble polyimide resin, and 35 to 50 parts by weight, preferably 40 to 50 parts by weight of the epoxy compound. The amount of the agent is preferably 0.5 parts by weight or less. In addition, if either soluble polyester resin or soluble polyimide resin is not used, the
It is difficult to obtain sufficient adhesive strength over a wide range of temperatures up to 200°C. Note that this mixture can be stored in a solution state for two months or more. Solvents that can be used to mix the resins constituting the adhesive of the present invention include N-methylpyrrolidone, N,N-dimethylacetamide,
N,N-dimethylformamide, dimethyl sulfoxide, tetrachloroethane, chloroform, dichloromethane, etc., all of which can be used as one or two types.
Can be used in a mixed system of more than one species. In the bonding process, the coating is applied to both sides of the material to be bonded, such as metal foil or ceramics, to a dry film thickness of approximately 10 to 50 μm (the same applies hereinafter) using a coating device, and at a temperature of 150 to 230℃. After drying for 1 to 20 minutes, the two sides are stacked together and heated and pressed at a temperature of 150 to 230° C. and a pressure of 1 to 20 Kgf/cm ² for 1 to 30 minutes. Furthermore, if more sufficient curing is desired, it is desirable to perform post-curing at about 200°C for about 2 hours. Examples Example 1 36 parts by weight of a soluble polyester synthesized using 9,9-bis(4-hydroxyphenyl)fluorene and terephthalic acid chloride and isophthalic acid chloride as aromatic acid chlorides in a ratio of 8:2,
Soluble polyimide synthesized using 9,9-bis(4-aminophenyl)fluorene and hexamethylene diamine in a ratio of 5:5 and 3,3',4,4'-benzophenonetetracarboxylic dianhydride. 24 parts by weight, 36 parts by weight of triazine type epoxy resin, 4 parts by weight of novolak type epoxy, and 0.3 parts by weight of dicyandiamide as a curing agent are dissolved in 233 parts by weight of N-methylpyrrolidone and mixed to make an adhesive with a concentration of 30% by weight. A composition was obtained. This adhesive composition was applied to a thickness of 20 μm on both sides of an iron plate and a degreased ceramic plate to be adhered, and after drying at 230°C for 10 minutes, the iron plate and ceramic plate were bonded at 210°C, 10 kgf/ Compression bonding was performed at cm ² for 10 minutes. Thereafter, post-curing was performed at 200°C for 2 hours. Table 1 shows the tensile shear strength results at 200°C after adhesion. Further, the tensile shear strength at each temperature of 25°C, 100°C, 150°C, 200°C, and 250°C was measured and shown in Table 2. Example 2 36 parts by weight of the solvent-soluble polyester used in Example 1, 24 parts by weight of the same solvent-soluble polyimide used in Example 1, 36 parts by weight of triazine-type epoxy resin, 4 parts by weight of novolak-type epoxy, and 0.3 parts by weight of dicyandiamide as a curing agent. Part by weight was dissolved in 233 parts by weight of N-methylpyrrolidone and mixed to obtain an adhesive composition having a concentration of 30% by weight. This adhesive composition was applied to both sides of two iron plates to be adhered to a thickness of 20 μm, and heated to 180°C.
After drying for 13 minutes at 210℃ and 10Kgf/ ^cm2 ,
Pressure bonding was performed for 10 minutes. Thereafter, post-curing was performed at 200°C for 2 hours. The tensile shear strength at 200°C is shown in Table 1. Example 3 36 parts by weight of the solvent-soluble polyester used in Example 1, 24 parts by weight of the solvent-soluble polyimide also used in Example 1, 40 parts by weight of triazine type epoxy resin, and 0.3 parts by weight of dicyandiamide as a curing agent were mixed with N.
- An adhesive composition having a concentration of 30% by weight was obtained by dissolving and mixing in 233 parts by weight of methylpyrrolidone. This adhesive composition was applied to both sides of two iron plates to be adhered to a thickness of 20 μm and heated at 180°C.
After drying for 13 minutes, heat the two iron plates at 210℃ and 10Kgf/ ^cm2 .
It was crimped for 1 minute. Thereafter, post-curing was performed at 200°C for 2 hours. The tensile shear strength at 200°C is shown in Table 1. Example 4 36 parts by weight of a soluble polyester synthesized using 9,9-bis(4-hydroxyphenyl)fluorene, terephthalic acid chloride and fumaric acid chloride in a ratio of 8:2, and the solvent used in Example 1 N-
It was dissolved in 233 parts by weight of methylpyrrolidone and mixed to obtain an adhesive composition having a concentration of 30% by weight. This adhesive composition was applied to both sides of an iron plate and a degreased ceramic plate to a thickness of 20 μm, and after drying at 230°C for 10 minutes, the iron plate and ceramic plate were bonded together at 210°C with 10kgf. / ^cm2 for 10 minutes. Thereafter, post-curing was performed at 200°C for 2 hours. The tensile shear strength results at 200°C are shown in Table 1. Comparative Example 1 Two iron plates were bonded together using 100 parts by weight of triazine-type epoxy and 8 parts by weight of dicyandiamide as a hardening agent. The adhesion process is the same as in Example 1.
The tensile shear strength at 200°C was 90Kgf/cm ² . In this case, since polyester resin and polyimide resin are not used, the adhesive strength at 200°C is poor. Comparative Example 2 Two iron plates were bonded together using 100 parts by weight of novolac type epoxy and 8 parts by weight of dicyandiamide as a hardening agent. The adhesion process is the same as in Example 1.
The tensile shear strength at 200°C was 65Kgf/cm ² .

【table】

[Table] Effects of the Invention The adhesive composition of the present invention takes advantage of the excellent heat resistance inherent in polyester resin and polyimide resin, and is effective in adhering materials such as iron and ceramics.
Excellent adhesive strength at high temperatures of 150℃ or higher. In addition, in the bonding process, we paid attention to the compatibility between the soluble polyester resin and the epoxy compound of the soluble polyimide resin, and by mixing the epoxy compounds, the bonding process was performed under conditions of 210℃, 10Kgf/cm ² for about 10 minutes. As a heat-resistant adhesive, it enables good adhesion through a low-temperature, low-pressure process. Since the adhesive composition of the present invention is liquid, it also has excellent workability.

Claims (1)

[Scope of Claims] 1 20 to 48 parts by weight of a soluble polyester resin obtained by reacting an aromatic diol represented by the formula with at least one of aromatic dicarboxylic acids and unsaturated dicarboxylic acids; [Formula] (However, in the formula, R represents H, CH ₃ or C ₂ H _5. ) An aromatic diamine represented by the formula and H ₂ N-
Soluble polyimide resin obtained by reacting an aliphatic diamine represented by C _o H _2o -NH ₂ (n = an integer of 2 to 8) with an aromatic tetracarboxylic acid.
12 to 36 parts by weight, _and 35 to ₅₀ parts by weight of an epoxy compound having two _or more epoxy groups in one molecule. A heat-resistant adhesive composition comprising: and a curing agent thereof.