JPS61143478A - Heat-resistant adhesive - Google Patents

Abstract

PURPOSE:To provide a heat-resistant adhesive consisting of polyamic acid and polyimic acid having specific recurring units, and capable of keeping the heat- resistance and adhesivity even at a high temperature. CONSTITUTION:The objective adhesive is composed of a polymer having the recurring unit of formula I [Y is 1-20C hydrocarbon group, hexafluoroisopropylidene, CO, S, SO or SO2 (oxide); Z is group of formula II or III; R is >=2C (cyclo)aliphatic group, (condensed polycyclic) aromatic group, or mutually connected non-condensed polycyclic aromatic groups]. The polymer wherein Z is group of formula II can be prepared by reacting (A) the compound of formula IV {e.g. 2,2-bis[4-(3-aminophenoxy)phenyl]propane} with (B) the compound of formula V (e.g. pyromellitic dianhydride) in a polar organic solvent (e.g. N,N-dimethylacetamide) preferably at <=50 deg.C e.g. for 4-24hr, and the product can be converted to another polymer wherein Y is group of formula III by thermally dehydrating e.g. at 100-300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial 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]

BACKGROUND ART Adhesives made of various organic synthetic polymers are conventionally known, and among these adhesives, polybenzimidazole adhesives, polyimide adhesives, and the like have been developed as adhesives with excellent heat resistance. In addition to the above-mentioned adhesives, adhesives for polyimide films, which are particularly heat-resistant films, include fluororesin, polyamideimide, silicone, epoxy novolasoc, epoxy acrylic, nitrile rubber, phenol, or polyester adhesives. have been developed, but these are not fully satisfactory, with some products having excellent adhesive strength but inferior adhesive strength, and others having excellent adhesive strength but inferior heat resistance. none).

A heat-resistant adhesive that is excellent in both heat resistance and adhesive strength is the polyimide adhesive developed by D. J. Progar et al. (U.S. Pat. No. 4,065,345).
No.) is only known.

[Problem that the invention seeks to solve]

An object of the present invention is to obtain a new heat-resistant adhesive that has heat resistance that does not reduce adhesive strength during and after use, even when used at high temperatures, and has stronger adhesive strength.

[Means for solving problems]

The present inventors have conducted extensive research to achieve the above object and have completed the present invention.

That is, the heat-resistant adhesive of the present invention has the following properties: represents a group selected from the group consisting of a group, a sulfonyl group or an oxide,

R represents an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a fused polycyclic aromatic group, or a non-containing group in which aromatic groups are interconnected directly or through a bridge member. Represents a tetravalent group selected from the group consisting of fused polycyclic aromatic groups. ) It is a heat-resistant adhesive made of a polymer having a repeating unit represented by:

The heat-resistant adhesive of the present invention is a polymer having a repeating unit represented by the formula (I), that is, a polyamic acid and/or polyimide having a repeating unit represented by the formula (I).

The heat-resistant adhesive of the present invention is a polymer having the formula (II) (II) (where Y is a direct bond, a divalent hydrocarbon group having 1 to 10 carbon atoms, a hexafluorinated isopropylidene group, carbonyl group, thio group, sulfinyl group, sulfonyl group, or oxide. Polyamic acid obtained by reacting with dianhydride and/or polyimide obtained by further cyclodehydration of this acid].

Diamines used in this method include bis(4-(
3-aminophenoxy)phenylcomethane, 1.1-bis(4-(3-aminophenoxy)phenyl]ethane,
1.2-bis(4-(3-aminophenoxy)phenyl)ethane, 2,2-bisC4-(3-aminophenoxy)phenyl]propane, 2,2-bisC4-(3-aminophenoxy)phenylcobutane , 2.2-bis[4-
(3-aminophenoxy)phenyl) -1,1,1,
3,3゜3-hexafluoropropane, 4,4'-bis(3-aminophenoxy)biphenyl, bis(4-(3
-aminophenoxy)phenylkoketone, bis(4-(
3-Aminophenoxy)phenyl] sulfide, bis[
Examples include 4-(3-aminophenoxy)phenyl]sulfoxide, bis(4-(3-aminophenoxy)phenyl)sulfone, bisC4-(3-aminophenoxy)phenyl ether, etc., which may be used alone or in combination of two or more. Used in combination.

The use of polyimides using ether diamines having such ether bonds and aromatic amino groups in the same molecule as adhesives is completely unknown.

These polymers can usually be produced by reacting an ether diamine with a tetracarboxylic dianhydride in an organic polar solvent.

The tetracarboxylic dianhydride used in this method has the formula (III) (wherein R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group,
Represents a tetravalent group selected from the group consisting of a monocyclic aromatic group, a fused polycyclic aromatic group, and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. . ) is a tetracarboxylic dianhydride represented by

That is, the tetracarboxylic dianhydride used is:
For example, ethylenetetracarboxylic dianhydride, cyclopencune carboxylic dianhydride, pyromellitic dianhydride,
3.3',4.4'-benzophenonetetracarboxylic dianhydride, 2,2:3,3'-hensiphenonetetracarboxylic dianhydride, 3.3-4. , r-biphenyltetracarboxylic dianhydride, 2.2: 3.3'-biphenyltetracarboxylic dianhydride, 2.2-bis(3,4
-dicarboxyphenyl)propanihydride, 2,2-
Bis(2,3-dicarboxyphenyl)propanihydride, bis(3,4-dicarboxyphenyl)ether diamine, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1.1-bis(2,3 -dicarboxyphenyl)ethane dianhydride, bis(2゜3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2.3,6.7-naphthalenetetracarboxylic acid dianhydride Anhydride, 1.4.5.8-naphthalenetetracarboxylic dianhydride, 1.2,5.6-naphthalenetetracarboxylic dianhydride, 1.2,3.4-
Benzenetetracarboxylic dianhydride, 3°4.9.10
-perylenetetracarboxylic dianhydride, 2°3.6.7
-Anthracentetracarboxylic dianhydride, L2,7.
Examples include 8-phenanthrenetetracarboxylic dianhydride.

These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

The polymer production reaction is usually carried out in an organic polar solvent.

Examples of organic polar solvents used in this reaction include N-
Methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, ■,3-dimethyl-2-imidazolidinone, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, dimethylsulfoxide, pyridine , dimethylsulfone, hexamethylphosphoramide, tetramethylurea, N-methylcaprolactam, butyrolactam, tetrahydrofuran,
m-dioxane, p-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 less, preferably 50°C or less.

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 tetracarboxylic dianhydride, ether diamine, solvent, and reaction temperature used, and the reaction is usually carried out for a time sufficient to complete the production of the polyamic acid represented by formula (I). Usually 4 to 24 hours is sufficient.

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

(IV) (wherein Y is a direct bond, selected from the group consisting of a divalent hydrocarbon group having 1 to 1 o carbon atoms, a hexafluorinated isopropylidene group, a carbonyl group, a thio group, a sulfinyl group, a sulfonyl group, or an oxide Z represents 00, R represents an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a fused polycyclic aromatic group, an aromatic group directly or (Represents a tetravalent group selected from the group consisting of non-fused polycyclic aromatic groups interconnected by crosslinking members.) Furthermore, by heating and dehydrating the obtained polyamic acid at 100 to 300 ° C. A corresponding polyimide having a repeating unit of the following formula (V) is obtained.

(V) (In the formula, Y is the same as above, and R is the same as above.) When using the thus obtained polymer as an adhesive, (I) Mainly the above formula (IV) When used as an adhesive solution containing polyamic acid represented by (2)
It is mainly divided into cases where polyimide represented by the above formula (V) is used.

In the case of fil, the adhesive solution mainly containing polyamic acid represented by the above formula (IV) is a solution in which polyamic acid is dissolved in an organic polar solvent, and ether diamine and tetracarboxylic dianhydride are dissolved in the organic polar solvent. It may also be a reaction product liquid containing a polyamide (acid) obtained by reacting with a polyamide. 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, the adhesive solution containing polyamic acid may be a solution or suspension partially containing polyimide.

When using an adhesive containing such a polyamic acid, a thin layer of the polyamic acid adhesive is applied to the objects to be bonded, and the adhered objects are then heated in air for the required time of 220 minutes. Preheat to about ℃ to remove excess solvent and convert the polyamic acid adhesive to a more stable polyimide.
then pressure of 1-1000 kg/cta, 50-4
By press-bonding at a temperature of 00°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 represented by the above formula (V) is the polyamic acid of the above formula (IV) heated and dehydrated to form, for example, a film, or is substantially the polyimide itself, which is made into a powder form. Further, it may contain a portion of the polyamic acid of formula (IV) above.

When using substantially polyimide, a film or powder is inserted between the objects to be adhered, and a
When crimped at a pressure of kg/ant and a temperature of 50-400°C and cured at a temperature of 100-400°C,
Adhesive substances can be firmly bonded.

〔Example〕

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

Example-1 In a container equipped with a stirrer, a reflux condenser, and a nitrogen introduction tube,
2. 41.0 g (0.1 mol) of 2-bis(4-(3-aminophenoxy)phenyl)propane and 188.4 g of N,N-dimethylacetamide were charged, cooled to around 0°C, and placed in a nitrogen atmosphere. Below, 17.44 g (0.08 mol) of pyromellitic dianhydride was added in 4 portions, taking care not to increase the solution temperature, and stirred at around 0°C for about 2 hours.Then, the above solution was warmed to room temperature. Reconstitute 4.36 g of pyromellitic dianhydride (0.02
mol) was added thereto, followed by stirring under a nitrogen atmosphere for about 20 hours. The polyamic acid thus obtained at 35°C
, N,N-dimethylacetamide at a concentration of 0.5% in the solvent was 1.5 dl/g. After casting the above polyamic acid solution on a glass plate,
A polyimide film was obtained by heating at 0°C and 300°C for 1 hour each. This polyimide film was heated to 130°C.
Cold rolled steel plate preheated to (JIS G3141.5
PCG/SD, 25 x 100 x 1.6 mm) and pressurized to 20 kg/od for 5 minutes at 340°C to bond.

The tensile shear adhesive strength of this product at room temperature is 300 kg.
/ cnl, and when this was further measured at a high temperature of 240°C, it was 180 kg/cjA. (The measurement method is based on JIS-6848 and 6850. The same applies hereinafter.) Comparative Example-1 2,2-bis(4-(3-aminophenoxy)phenyl)propane in Example-1 was [4-
(4-Aminophenoxy)phenyl] The same procedure as in Example 1 was carried out except that propane was used, at 35°C, N,
A polyamic acid with an intrinsic viscosity of 1.70 dl/g at 0.5% concentration in N-dimethylacetamide solvent was obtained.

After casting this polyamic acid solution on a glass plate,
Polyimide films were obtained by heating at 100°C, 200°C and 300°C for 1 hour each. 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 is 84 kg.
/ It was cra. When this was further measured at a high temperature of 240°C, it was found to be 67 kg/cra.

Example-2 In a container equipped with a stirrer, a reflux condenser, and a nitrogen introduction tube,
39.6 g (0.1 mol) of bis(4-(3-aminophenoxy)phenyl coketone) and 215.4 g of N,N-dimethylacetamide were charged, and 3.3-4. .Add 32.2 g (0.1 mol) of 4'-hensiphenotetracarboxylic dianhydride as a dry solid little by little while being careful not to increase the solution temperature.
Stirred at room temperature for about 23 hours. The polyamic acid obtained in this way was heated to 0.0% in N,N-dimethylacetamide solvent at 35°C.
．． The intrinsic viscosity at 5% concentration was 0.87 dl/g. Cold rolled steel plate washed with the above polyamic acid adhesive solution using trichlorethylene (same as Example 1. The same applies hereinafter)
After applying the coating to
It was crimped by applying pressure at kg/ctA for 5 minutes. The thickness of the applied adhesive was 35 microns.

The tensile shear adhesive strength of this product is 270 kg/at room temperature.
It was cni. When this was further measured at a high temperature of 240''C, it was 167 kg/c+ (.

Example-3 In a container equipped with a stirrer, a reflux condenser, and a nitrogen introduction tube,
39.6 g (0.1 mol) of bis(4-(3-aminophenoxy)phenylkoketone) were dissolved in 182.9 g of N,N-dimethylacetamide under a nitrogen atmosphere.

This was cooled near O''CC, and while stirring, 17.44 g of pyromellitic dianhydride (0.08
mol) was added as a dry solid in five portions while paying attention to the solution temperature, and the mixture was stirred for 1 hour. Next, the above solution was returned to room temperature, and under a nitrogen atmosphere, 3.92% of pyromellitic dianhydride was added.
g (0,018 mol) was added and the mixture was subsequently stirred for about 20 hours under a nitrogen atmosphere. 0.5 of the polyamic acid thus obtained in N,N-dimethylacetamide solvent at 35°C.
The intrinsic viscosity in % concentration was 0.85 aJ/g. After casting the above polyamic acid solution on a glass plate, 10
Polyimide films were obtained by heating at 0°C, 1200°C, and 300°C for 1 hour each. This polyimide film was inserted between two cold-rolled steel plates preheated to 130°C, and pressed to 20 kg/cnt at 340°C for 5 minutes to bond them.

The tensile shear adhesive strength of this product at room temperature is 240 kg.
/ cnl. When this was further measured at a high temperature of 240℃, it was 163kg/c++? Met.

Example-4 In a container equipped with a stirrer, a reflux condenser, and a nitrogen introduction tube,
39.6 g (0.1 mol) of bis(4-(3-aminophenoxy)phenyl coketone) and 184.2 g of N,N-dimethylacetamide were charged under a nitrogen atmosphere, cooled to around 0°C, and stirred. Meanwhile, under a nitrogen atmosphere, 17.44 g (0.08 mol) of pyromellitic dianhydride was added as a dry solid in five portions, paying attention to the solution temperature, and stirred for 1 hour.Then, the above solution was brought to room temperature. Reconstitute 4.36 g of pyromellitic dianhydride (0,
02 mol) was added thereto, followed by stirring under a nitrogen atmosphere for about 20 hours. 3 of the polyamic acid thus obtained
The intrinsic viscosity at 5° C. and 0.5% concentration in N,N-dimethylacetamide solvent was 2.8 dl/g. After casting the above polyamic acid solution on a glass plate,
Polyimide films were obtained by heating at 200°C and 300°C for 1 hour each.

This polyimide film was inserted between cold-rolled steel plates preheated to 130°C, and the film was heated to 20 kg/c at 340°C.
nl was pressurized for 5 minutes to bond.

The tensile shear adhesive strength of this product is 280 kg/- at room temperature.
Met. When this was further measured at a high temperature of 240°C, it was found to be 192 kg/cnT.

Comparative Example-2 All operations were the same as in Example-4 except that bis(4-(3-aminophenoxy)phenylkoketone in Example-4 was replaced with bis[4-(4-aminophenoxy)phenylkoketone) A polyamic acid having an intrinsic viscosity of 2.8 di/g at 0.5% concentration in N,N-dimethylacetamide solvent at 35°C was obtained.

A polyimide film was obtained from this polyamic acid by the same operation as in Example 4.

When this film was used to pressure-bond a cold rolled steel plate under the same conditions as in Example 4, the tensile shear adhesive strength was 60 kg/- at room temperature. When this was further measured at a high temperature of 240°C, it was 48 kg/cnl.

Examples 5 and 6, Comparative Examples 3 and 4 Various diamines were used in place of 2,2-bis(4-(3-aminophenoxy)phenyl)propane in Example 1, and diamine, N,N-dimethyl The reaction was carried out in the same manner as in Example 1, except that the amounts of acetamide and pyromellitic dianhydride were changed, and the results shown in Table 1 were obtained.

〔Effect of the invention〕

The present invention provides an 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) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, Y is a direct bond, a divalent hydrocarbon group having 1 to 10 carbon atoms, hexafluorinated isopropylidene represents a group selected from the group consisting of a group consisting of a carbonyl group, a thio group, a sulfinyl group, a sulfonyl group, or an oxide, and Z is ▲ has a mathematical formula, chemical formula, table, etc. ▼ or ▲ has a mathematical formula, chemical formula, table, etc. ▼ R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a fused polycyclic aromatic group, or a non-fused aromatic group in which aromatic groups are interconnected directly or through a bridge member. (Represents a tetravalent group selected from the group consisting of polycyclic aromatic groups.) A heat-resistant adhesive comprising a polymer having a repeating unit represented by: