JPS61291670A - Heat-resistant adhesive - Google Patents

Abstract

PURPOSE:To titled novel adhesive, consisting of a polymer having specific repeating units and capable of exhibiting powerful adhesive strength without deteriorating the heat resistance and keeping high adhesive strength particularly even at a high temperature. CONSTITUTION:An adhesive consisting of a polymer having repeating units expressed by formula I (Y is formula II or III). The polymer having the repeating units expressed by formula I can be obtained by polycondensing 1, 3-bis (3-aminophenoxy) bezene with 3, 3', 4' 4'-benzophenonetetracarboxylic acid dianhydride and,as necessary, cyclizing the resultant polycondensate through dehydration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-resistant adhesive, and particularly to an adhesive that has strong adhesive strength and excellent heat resistance.

[Conventional technology]

Many heat-resistant adhesives made of organic synthetic polymers have been known as adhesives for various high-performance materials used in fields such as electronics, aerospace equipment, and transportation equipment. As excellent adhesives, polybenzimidazole adhesives and polyimide adhesives have been developed.

In addition to the adhesives mentioned above, adhesives such as fluororesin, polyamideimide, silicone, epoxy novolac, epoxy acrylic, nitrile rubber, phenol, or polyester have been developed, but these are not satisfactory in terms of heat resistance. Some adhesives have poor adhesive strength, while others with excellent adhesive strength have poor heat resistance and are not fully satisfactory. As a heat-resistant adhesive, a polyimide adhesive developed by J. Progar et al. (U.S. Pat. No. 4,065,34
No. 5) is only known.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a new heat-resistant adhesive that does not lose adhesive strength during or after use, even when used at high temperatures.

[Means for solving problems]

The present inventors have made extensive studies to achieve the above object, and as a result, have completed the present invention.

That is, the present invention is a heat-resistant adhesive made of a polymer having a repeating unit represented by formula (I) (wherein Y represents or).

That is, the heat-resistant adhesive of the present invention has 1,3-bis(3-
aminophenoxy)benzene (hereinafter abbreviated as APB).

) and 3.3 (4,4'-benzophenonetetracarboxylic dianhydride (hereinafter abbreviated as BTDA)) and/or a polyamic acid obtained by further cyclodehydration of this. be.

The following examples are known as polyimides using APB. An example is an acetylene-terminated polyimide oligomer (N, Bilow et al.) prepared from APBSBTDA and 3-aminophenylacetylene.

U.S. Patent No. 3,845.018 and U.S. Pat. No. 3.879
．． No. 349; National 5tarch & Ch.
Thermid-600, manufactured by E.M., Inc.), and when this oligomer is thermally cured, addition polymerization occurs due to the terminal acetylene groups to yield polyimide.

Another example is a polycondensation polyimide consisting of APB and pyromellitic anhydride (T, P, Ganesoto et al., JP-A-59-1
70.122) Yes.

The polymer according to the present invention is a polycondensation polymer obtained by using APB as the diamine component and BTDA as the tetracarboxylic dianhydride component, and is a polymer that is completely unknown as a heat-resistant adhesive. .

The polymer comprising the combination of APB and BTDA of the present invention is a particularly excellent heat-resistant adhesive.

On the other hand, for example, by changing this combination, APB, that is, 1
, 3-bis(3-phenoxy)benzene, using 1,3-bis(4-phenoxy)benzene or 1,4-bis(4-aminophenoxy)benzene, which is an isomer of the substitution position, Polymers obtained from these and BTDA have extremely low adhesive strength and cannot be used as adhesives.

Examples of the organic solvent used in this reaction include N.

N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methyl caprolactam, 1,2-dimethoxyethane, bis(
2-methoxyethyl)ether, 1.2-bis(2-methoxyethoxy)ethane, bis(2-(2-methoxyethoxy)ethyl)ether, tetrahydrofuran, 1.
Examples include 3-dioxane, 1,4-dioxane, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethylurea, hexamethylphosphoramide, and the like. Further, these organic solvents may be used alone or in combination of two or more.

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

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

The reaction time varies depending on the type of solvent used and the reaction temperature, and is usually 4 to 24 hours, which is sufficient to complete the production of the polyamic acid represented by the following formula (If).

Through such a reaction, a polyamic acid having a repeating unit of the following formula (U) can be obtained.

(In the formula, Y represents.) Furthermore, this polyamic acid is dehydrated by heating at 100 to 300°C or chemically dehydrated with a hydrophilic agent such as acetic anhydride to obtain a corresponding polyamic acid having a repeating unit of the following formula (DI). Polyimide is obtained.

(II[) (In the formula, Y represents.) When the thus obtained polymer is used as an adhesive, (I) the case where it is used as an adhesive solution mainly containing the polyamic acid, and (2 ) The above-mentioned polyimide is used.

In the case of (I), the adhesive solution mainly containing polyamic acid is a solution in which polyamic acid is dissolved in an organic solvent. It may also be a reaction product liquid containing. It may also be one that has polyamic acid as its main component and contains polyimide, which is a cyclized product of polyamic acid.

Therefore, an adhesive solution containing polyamic acid is
It may also be a solution or suspension partially containing polyimide.

When using such an adhesive containing polyamic acid, apply a thin layer of polyamic acid solution to the objects to be bonded, and then preheat in air to about 220°C for the required time to remove excess The solvent is removed and the polyamic acid adhesive is converted to a more stable polyimide, which is then overlaid with another adherend, followed by a pressure of 1-1,000 kg/cs2,
By press-bonding at a temperature of 50 to 400°C and curing at a temperature of 100 to 400°C, objects to be adhered can be firmly bonded.

In the case of (2), the polyimide is substantially the polyimide itself, which is made into a film form by heating or chemically dehydrating the polyamic acid, or into a powder form. In this case, there is no problem even if the polyamic acid is partially contained.

When using such polyimide, a film or powder is inserted between the objects to be adhered, and the
By pressing at a pressure of 0 kg/c112 at a temperature of 50 to 400°C and curing at a temperature of 100 to 400°C, the adhesive substance can be firmly bonded.

〔Example〕

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

Example-1 Volume W equipped with a stirrer, reflux condenser, and nitrogen introduction pipe
, A P B 14.6 g (0.05%) and
Charge 92.1 g of N, N-dimethylacetamide,
16.1 g of 3.3', 4.4'-benzophenone tetracarboxylic dianhydride (0,0
5 mol) was added in four portions while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours. Logarithmic viscosity of the polyamic acid thus obtained (N,N-dimethylacetamide solvent.

Concentration 0-5g/100ml solvent, measured at 35°C, and so on.

) is 1.23d! /g. After casting the above polyamic acid solution on a glass plate, 100℃, 200℃
and 300° C. for 1 hour each to obtain a pale yellow transparent polyimide film. The glass transition temperature of this polyimide film was 197° C. (according to TMA Needleman Corporation, hereinafter the same), and the 5% thermal decomposition temperature was 539'C (according to DTA-TG, hereinafter the same).

A cold rolled steel plate (JIS G3141.5PCC/SD, 2
5X 100X1.6mm) and heated at 340℃ for 2
Pressure was applied to 0 kg/cI112 for 5 minutes to bond.

The tensile shear adhesive strength of this product at room temperature is 310 kg/
cI112, which was further measured at a high temperature of 180°C and found to be 205 kg/cm2. (The measurement method is based on JIS-6848 and 6850. The same applies hereinafter.) Example-2 14.6 g (0.05 mol) of APB in a nitrogen atmosphere
was added to 92.1 g of bis(2-methoxyethyl) ether and while stirring 3.3) 4.4'-benzophenonetetracarboxylic dianhydride 15.8 g (0
,049 mol) of dry solid was added in small portions. During this time, the reactor was cooled to maintain a temperature of 25 to 30°C, and after adding 3.3-4.4'-benzophenonetetracarboxylic dianhydride, it was stirred at room temperature under a nitrogen atmosphere for about 20 hours. . The logarithmic viscosity of the polyamic acid thus obtained was 0.73 d!/g.

The above polyamic acid adhesive solution was applied to a cold rolled steel plate (same as above) that had been cleaned with trichlorethylene, and heated to 100°C.
After heating and drying at 220° C. for 1 hour and 1 hour at 220° C., cold rolled steel plates were stacked and crimped at 300° C. and 20 kg/cIII2 for 5 minutes.

The thickness of the applied adhesive was 30 microns.

The tensile shear adhesive strength of this product is 277k at room temperature.
g/cff12. When this was further measured at a high temperature of 200°C, it was found to be 155 kr/2.

Comparative Example-1 APB in Example-1, that is, 1.3-bis(3-
Example 1 except that 1,4-bis(4-aminophenoxy)benzene was used instead of aminophenoxy)benzene.
By the same operation as above, the logarithmic viscosity was 1.23d! /g of polyamic acid was obtained. After casting this polyamic acid solution on a glass plate, it was heated at 100°C, 200°C and 300°C.
Each was heated at ℃ for 1 hour to obtain a polyimide film. The glass transition temperature of this polyimide film is 446°C1
The 5% pyrolysis temperature was 500°C. Using this polyimide film, a cold rolled steel plate was crimped under the same conditions as in Example-1. The tensile shear adhesive strength of this product at room temperature was Qky/cm2.

Comparative Example-2 A logarithmic viscosity of 1.0 was obtained by performing the same operations as in Example-1 except that APB in Example-1 was replaced with 1,3-bis(4-aminophenoxy)benzene. OfJ/g of polyamic acid was obtained. This polyamic acid solution was cast onto a glass plate, and then heated at 100°C, 200°C and 300°C for 1 hour each to obtain a polyimide film. The glass transition temperature of this polyimide film was 320°C, and the 5% thermal decomposition temperature was 514°C.

Using this polyimide film, a cold rolled steel plate was crimped under the same conditions as in Example-1. The tensile shear adhesive strength of this product at room temperature was 110kr/2.

〔Effect of the invention〕

The present invention provides a novel heat-resistant adhesive that exhibits strong adhesive strength without reducing heat resistance and can maintain high adhesive strength even at high temperatures.

Claims (1)

[Claims] Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, Y is ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ A heat-resistant adhesive made of a polymer having a repeating unit represented by