JPH0765027B2 - Heat resistant adhesive - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-resistant adhesive, and particularly to an adhesive excellent in strong adhesive force and heat resistance.

[Conventional technology]

Heretofore, adhesives made of various organic synthetic polymers have been known, and among these adhesives, those having excellent heat resistance have been developed, such as polybenzimidazole-based and polyimide-based adhesives. In addition to the above-mentioned adhesives, fluororesin, polyamideimide, silicone, epoxy novolac, epoxy acryl, nitrile rubber, phenolic or polyester adhesives have been developed as adhesives for polyimide film, which is a heat-resistant film. However, those which are satisfactory in terms of heat resistance also have poor adhesive strength, while those which are excellent in adhesive strength are inferior in heat resistance and are not sufficiently satisfactory. As a heat resistant adhesive,
DJProgar has excellent heat resistance and adhesive strength.
Polyimide adhesive (US Pat. No. 4,
(No. 065,345) Is only known. However, in order to apply this polyimide as an adhesive, it is necessary to apply it at a considerably high temperature and high pressure, the applicability is improved, and a polyimide having excellent heat resistance, mechanical strength and adhesiveness is required. It was

[Problems to be solved by the invention]

The object of the present invention is applicable to polyimide itself as an adhesive and its applicability is improved, and even when the adhesive force is used at high temperature, during use, it does not decrease after use, heat resistance, and stronger. It is to obtain a novel heat-resistant adhesive having adhesive strength.

[Means for solving problems]

The present inventors have conducted intensive studies to achieve the above-mentioned object, and completed the present invention.

That is, the heat-resistant adhesive of the present invention has the formula (I) (Where Y is And R is Represents a tetravalent group selected from the group consisting of ) Has a repeating unit represented by (In these formulas, R'is Represents a tetravalent group selected from the group consisting of: ) Group represented by or It is a heat resistant adhesive comprising a polymer film or powder which is a group represented by.

The heat-resistant adhesive of the present invention comprises a polymer having a repeating unit represented by the above formula (I), that is, a polyimide having a repeating unit represented by the above formula (I).

Such a polymer which is a heat-resistant adhesive of the present invention uses 1,3-bis (3-aminophenoxy) benzene (hereinafter abbreviated as APB) as a diamine component. A polyamic acid obtained by reacting one or more tetracarboxylic acid dianhydrides with a polyimide obtained by further dehydration cyclization.

As a polyimide using APB, APB, 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride and polyamic acid oligomer or polyimide oligomer of terminal acetylene produced from 3-aminophenylacetylene, these oligomers Is applied as a molding coating or adhesive, and is then heated to produce a high molecular weight addition reaction type polyimide (National Starch &
Chem., Trade name: Thermid-600) is known (US Pat. Nos. 3,845,018 and 3,879,349).

However, this high molecular weight addition-type polyimide lacks applicability as a molding coating or an adhesive.

The polycondensation type polyimide of the present invention comprising APB and tetracarboxylic dianhydride has never been known as an adhesive.

These polymers can usually be produced by reacting APB with tetracarboxylic dianhydride in an organic solvent.

The tetracarboxylic dianhydride used in this method has the formula (II) (In the formula, R is Represents a tetravalent group selected from the group consisting of: ) Is a tetracarboxylic dianhydride.

That is, as the tetracarboxylic dianhydride used,
For example, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3, 4-
Dicarboxyphenyl) ether dianhydride, bis (3,4
-Dicarboxyphenyl) sulfone dianhydride, 2,3,6,7
-Naphthalene tetracarboxylic dianhydride.

These tetracarboxylic dianhydrides may be used alone or
Used as a mixture of two or more species.

The polymer formation reaction is usually carried out in an organic solvent. Examples of the organic solvent used in this reaction include N-methyl-
2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethylsulfoxide, pyridine, Dimethyl sulfone, hexamethylphosphoramide,
Tetramethylurea, N-methylcaprolactam, butyrolactam, tetrahydrofuran, m-dioxane, p-
Examples thereof include dioxane, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl] ether and the like.

The reaction temperature is usually 60 ° C or lower, preferably 50 ° C or lower.

The reaction pressure is not particularly limited and can be carried out at normal pressure.

The reaction time varies depending on the tetracarboxylic dianhydride used, the type of solvent and the reaction temperature, and is usually the following formula (II
The reaction is carried out for a sufficient time to complete the formation of the polyamic acid represented by I). Usually 4 to 24 hours is sufficient.

By such a reaction, the following formula (III) (Where Y is Here, R is as described above. ) Has a repeating unit represented by (In the formula, R ′ is as described above),
Or A polyamic acid which is a group represented by is obtained.

Further, by dehydrating the obtained polyamic acid at 100 to 300 ° C, the following formula (IV) [Where Y is (Wherein R is as described above)] and the terminal is (Wherein R ′ is as described above) or A corresponding polymer, polyimide, which is a group represented by

When using the polymer thus obtained as an adhesive, a polyimide film, that is, before being applied to an object to be adhered, a polyimide film obtained by imidizing a poiamic acid, or a solution of a polyamic acid to the object to be adhered It is applied as a polyimide coating film obtained by coating and imidizing this, or as a manufactured polyimide powder.

Specifically, (1) a method of forming a polyimide coating film on an object to be adhered and adhering a further object to be adhered on the film, that is, mainly using a polyamic acid represented by the above formula (III) as an organic solvent. Solution containing the polyamic acid obtained by reacting APB with tetracarboxylic acid dianhydride in an organic solvent, and a polyamic acid as a main component, which also contains a polyamic acid ring. A solution or suspension containing a part of polyimide containing a polyimide as a compound, is applied to a thin layer on an adherend to be bonded,
Then, the adherend is adhered in air for a required time, preheated to about 220 ° C. to remove excess solvent, and the polyamic acid is converted into a more stable polyimide as a polyimide coating film. The object to be adhered can be firmly adhered by pressure-bonding the object to be adhered at a pressure of 1 to 1000 kg / cm ² at a temperature of 50 to 400 ° C. and curing at a temperature of 100 to 400 ° C. Further, (2) a method of inserting a polyimide film or powder between the adherends and adhering it, that is, heating and dehydrating the polyamic acid of the above formula (III) to obtain the above formula (IV)
The polyimide represented by is inserted into a material to be adhered, for example, by inserting a substantial polyimide film such as a film-shaped polyimide film or a powdered polyimide powder.
Pressure of ~1000kg / cm ^2, and pressed at a temperature of 50 to 400 ° C., 100 to
Curing at a temperature of 400 ° C can firmly bond the adherend.

The polyimide may contain a part of the poiamic acid represented by the above formula (III).

〔Example〕

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

Example-1 In a container equipped with a stirrer, a reflux condenser and a nitrogen introduction tube,
In a nitrogen atmosphere, 16.5 g (0.05 mol) of APB is added to 76.5
In addition to g of N, N-dimethylacetamide, 10.9 g (0.05 mol) of pyromellitic dianhydride was added little by little to the dry solid while stirring. During this period, the temperature in the reactor was cooled so as to keep it at 25 to 30 ° C., and after adding pyromellitic dianhydride, stirring was continued at room temperature under a nitrogen atmosphere for about 20 hours. The polyamic acid thus obtained at 35 ° C., N, N
-Intrinsic viscosity at 0.5% concentration in dimethylacetamide solvent was 1.10 dl / g. After casting the above polyamic acid solution on a glass plate, 1 at 100 ℃, 200 ℃ and 300 ℃
After heating for a period of time, a pale yellow transparent polyimide film was obtained. Cold-rolled steel sheet (JIS G3141, SPCC / SD, 25 × 100 × 1.6 m
m), and pressed at 20 ° C./cm ² for 5 minutes at 340 ° C. for pressure bonding. The tensile shear bond strength of this product at room temperature is
It was 300 kg / cm ² , and when it was further measured at a high temperature of 200 ° C., it was 180 kg / cm ² .

Comparative Example 1 In Example 1, the amount of pyromellitic dianhydride used was 1
A polyamic acid was produced in the same manner as in Example 1 except that the amount was 0.5 g (0.048 mol). In addition to this polyamic acid,
0.5 g (0.004 mol) of 5-aminophenylacetylene was added, and the mixture was stirred for 3 hours to react with the terminal. The polyamic acid solution thus obtained was used to evaluate the adhesiveness in the same manner as in Example 1. The tensile shear strength at room temperature was 160 kg / cm.
² and 140 kg / cm ² at 200 ° C., showing a small decrease in adhesive strength at high temperatures, but poor adhesive strength at room temperature.

Examples 2-6 As tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride (Example 2) Bis (3,4-dicarboxyphenyl) ether dianhydride (Example 3), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (Example 4), bis (3,4-dicarboxyphenyl) sulfone dianhydride (Example 5), 2 , 3,6,7−
A polyimide was obtained in the same manner as in Example 1 except that naphthalenetetracarboxylic dianhydride (Example 6) was used.

The adhesive strength of these polyimides in a greenhouse is 310, respectively.
340,300,320,320kg / cm ² , and at 200 ℃ each 18
It was 0,160,190,180,180 kg / cm ² .

〔The invention's effect〕

The present invention provides an adhesive that exhibits a strong adhesive force without lowering heat resistance and can maintain a high adhesive force even at high temperatures.

 ─────────────────────────────────────────────────── --Continued front page (56) References JP-A-55-156917 (JP, A) JP-A-50-5348 (JP, A) Polymer Science U.S. S. R Vol. 21 (9) PP. 2196-PP / 2206

Claims (1)

[Claims] 1. A formula (I) (Where Y is And R is Represents a tetravalent group selected from the group consisting of: ) Has a repeating unit represented by (In these formulas, R'is Represents a tetravalent group selected from the group consisting of: ) Group or A heat-resistant adhesive composed of a polymer film or powder which is a group represented by.