JP3014526B2 - Heat resistant adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant adhesive, and more particularly to a high heat-resistant adhesive having excellent peel strength.

[0002]

2. Description of the Related Art Conventionally, adhesives made of various organic polymers have been known. Among them, adhesives having excellent heat resistance, such as polybenzimidazole-based and polyimide-based adhesives, have been developed. I have. In particular, as an adhesive for a polyimide-based film that is a heat-resistant film, other than the above-mentioned adhesive, a fluorine-based resin, polyamideimide, silicone,
Adhesives such as epoxy novolak, epoxy acrylic, nitrile rubber, phenol, or polyester have been developed. However, those which are satisfactory in terms of heat resistance are inferior in adhesive strength, while those having excellent adhesive strength are inferior in heat resistance, and are not sufficiently satisfactory.

As heat-resistant adhesives having excellent heat resistance and adhesive strength, US Pat.
-143478 and several examples in Japanese Patent Application Laid-Open No. 61-291670, all of which have excellent tensile shear adhesive strength, and are heat-resistant adhesives having excellent peel strength (peeling strength). This is not an example.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-resistant and excellent peel strength (peeling strength) which does not decrease even when used at a high temperature or during use after bonding. To provide a novel heat-resistant adhesive having the same.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, using 4,4-bis (3-aminophenoxy) biphenyl as an aromatic diamine component, As the aromatic tetcarboxylic dianhydride component, 3,
Using a mixture of 3 ', 4,4'-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, the polyimide obtained by reacting them has high heat resistance and excellent peel strength. As a result, the present invention has been completed.

That is, the heat-resistant adhesive of the present invention has the formula (1)

Embedded image 20 to 80 mol% of a structural unit represented by the following formula:

Embedded image A heat-resistant adhesive comprising a polyimide having a structural unit represented by 20 to 80 mol% , and a varnish containing the polyimide;

Further, in a polymer molecule which is a precursor of the polyimide , a compound represented by the formula (3)

Embedded image 20 to 80 mol% of a structural unit represented by the following formula:

Embedded image Is a polyamic acid having a structural unit represented by 20 to 80 mol% , and the polyamic acid is dissolved in N, N-dimethylacetamide at a concentration of 0.5 g / 100 ml and measured at 35 ° C. A heat-resistant adhesive made of polyimide obtained by thermally and chemically imidizing polyamic acid having a logarithmic viscosity of 0.1 to 3.0 dl / g.

A varnish containing the above-mentioned polyamic acid.

As an aromatic diamine component, 4,4′-bis (3
-Aminophenoxy) Biphenyl-based polyimides are already USP4,8 as highly heat-resistant thermoplastic polymers.
47,349 and the like. However, this 4,4'-
Bis (3-aminophenoxy) biphenyl is converted to 3,3 ', 4,4'-
It is not known that a polyimide obtained by reacting with a mixture of biphenyltetracarboxylic dianhydride and pyromellitic dianhydride has particularly excellent heat-resistant adhesiveness in terms of peel strength. , For the first time by the present invention.

[0010] The polyimide or polyamic acid in the heat resistant adhesive of the present invention is produced as follows. The aromatic diamine component used for the production of this polyimide or polyamic acid has the formula (5)

Embedded image 4,4'-bis (3-aminophenoxy) biphenyl represented by

The aromatic tetracarboxylic dianhydride used is represented by the formula (6)

Embedded image 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride represented by the formula:

Embedded image And a mixture of these two kinds of aromatic tetracarboxylic dianhydrides.

The polyimide or polyamic acid as the adhesive of the present invention is mainly composed of the above-mentioned aromatic diamine component and aromatic tetracarboxylic dianhydride. Equation (8) as long as it is not damaged

Embedded image (Wherein, R represents an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group,
A tetravalent group selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which the aromatic groups are connected to each other directly or by a crosslinking member; There is no problem even if a part of the tetracarboxylic acids represented by the formula (1) is contained.

That is, examples of tetracarboxylic dianhydrides which can be partially substituted include, for example, ethylene tetracarboxylic dianhydride, cyclopentanecarboxylic dianhydride,
3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,
2 ', 3,3'-benzophenonetetracarboxylic dianhydride, 2,
2 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,
2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 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 dianhydride, 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-anthracenetetra Examples thereof include carboxylic dianhydride and 1,2,7,8-phenanthrenetetracarboxylic dianhydride.

Further, for the purpose of sealing the terminal of the polymer of polyimide or polyamic acid and controlling the molecular weight, the following formula (9)

Embedded image Wherein Z is a monocyclic aromatic group, a condensed polycyclic aromatic group, or a non-condensed polycyclic aromatic group selected from the group consisting of a non-condensed polycyclic aromatic group in which the aromatic groups are connected to each other directly or by a bridge member. An aromatic dicarboxylic anhydride represented by the following formula:

Or equation (10)

Embedded image (Wherein, Z is selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which the aromatic groups are connected to each other directly or by a bridge member. A method of using an aromatic monoamine represented by the following formula (which represents a divalent group) is well known, but these methods can be applied to the present invention without any problem.

The dicarboxylic anhydrides used in these methods include phthalic anhydride, 2,3-benzophenone dicarboxylic anhydride, 3,4-benzophenone dicarboxylic anhydride, and 2,3-dicarboxyphenyl phenyl ether Anhydride, 3,4-dicarboxyphenylphenyl ether anhydride, 2,3-biphenyldicarboxylic anhydride, 3,4-biphenyldicarboxylic anhydride, 2,3-dicarboxyphenylphenylsulfone anhydride, 3,4 -Dicarboxyphenyl phenyl sulfone anhydride, 2,3-dicarboxyphenyl phenyl sulfide anhydride, 1,2-naphthalenedicarboxylic anhydride, 1,8-naphthalenedicarboxylic anhydride, 1,2-anthracene dicarboxylic anhydride , 2,3-anthracene dicarboxylic anhydride, 1,9-anthracene dicarboxylic anhydride and the like. These dicarboxylic anhydrides may be substituted with a group having no reactivity with amine or dicarboxylic anhydride.

When an aromatic monoamine is used,
As the aromatic monoamine, for example, aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-xylidine, 2,4-xylidine, 2,5-xylidine, 2,6-xylidine, 3,4- Xylidine, 3,5-xylidine, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-bromoaniline, m-bromoaniline, p-bromoaniline, o-nitroaniline, m-nitroaniline, p- Nitroaniline, o-
Aminophenol, m-aminophenol, p-aminophenol, o-anisidine, m-anisidine, p-anisidine,
o-phenetidine, m-phenetidine, p-phenetidine, o-
Aminobenzaldehyde, m-aminobenzaldehyde,
p-aminobenzaldehyde, o-aminobenzonitrile,
m-aminobenzonitrile, p-aminobenzonitrile, 2-
Aminobiphenyl, 3-aminobiphenyl, 4-aminobiphenyl, (2-aminophenyl) (phenyl) ether,
(3-aminophenyl) (phenyl) ether, (4-aminophenyl) (phenyl) ether, 2-aminobenzophenone, 3-aminobenzophenone, 4-aminobenzophenone, (2-aminophenyl) (phenyl) sulfide,
(3-aminophenyl) (phenyl) sulfide, (4-aminophenyl) (phenyl) sulfide, (2-aminophenyl) (phenyl) sulfone, (3-aminophenyl)
(Phenyl) sulfone, (4-aminophenyl) (phenyl) sulfone, α-naphthylamine, β-naphthylamine, 1-amino-2-naphthol, 2-amino-1-naphthol, 4-amino-1-naphthol, 5- Amino-1-naphthol, 5-amino-2-naphthol, 7-amino-2-naphthol, 8-amino-1-naphthol, 8-amino-2-naphthol, 1-aminoanthracene, 2-aminoanthracene, 9-
And aminoanthracene. These aromatic monoamines may be substituted with a group having no reactivity with amine or dicarboxylic anhydride.

The polyamic acid forming reaction is usually carried out in an organic solvent. As the organic solvent used in this reaction,
For example, 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, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2
-Methoxyethoxy) ethane, bis 2- (2-methoxyethoxy) ethyl ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, O-cresol,
m-cresol, p-cresol, cresylic acid, p-chlorophenol, anisole, phenol and the like.

The polyimide or polyamic acid relating to the heat-resistant adhesive of the present invention is produced as follows using the above-mentioned main raw materials, sub-raw materials or reactants. 4,4′-bis (3-aminophenoxy) biphenyl of the formula (5),
The amounts of the 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride of the formula (6) and the pyromellitic dianhydride of the formula (7) used are 4,4′-bis (3-aminophenoxy) ) relative to biphenyl, 3,3 ', 20 to 80 mole% 4,4'-biphenyltetracarboxylic acid dianhydride 20 to 80 mol% and pyromellitic dianhydride. The aromatic diamine component and the aromatic tetracarboxylic dianhydride, the aromatic dicarboxylic anhydride and the aromatic monoamine as a polymer terminal sealing agent and a molecular weight controlling agent are reacted in the organic solvent, polyimide, To obtain a polyamic acid which is a precursor of

The reaction temperature at this time is usually 60 ° C. or lower, preferably 50 ° C. or lower. The reaction pressure is not particularly limited, and the reaction can be sufficiently performed at normal pressure. The reaction time varies depending on the ratio of the tetracarboxylic dianhydride used, that is, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and the use ratio of pyromellitic, the type of the solvent and the reaction temperature, Usually, the reaction is carried out for a time sufficient to complete the formation of the polyamic acid.
Usually 4 to 24 hours is sufficient.

By this reaction, in a polymer molecule which is a precursor of polyimide, a compound represented by the formula (3)

Embedded image 20 to 80 mol% of a structural unit represented by the following formula:

Embedded image A polyamic acid having a structural unit represented by 20 to 80 mol% is obtained.

The resulting polyamic acid is 3, 3 ', 4,
If the amount of 4'-biphenyltetracarboxylic dianhydride is less than 20 mol% of the tetracarboxylic dianhydride used, the peel strength of the obtained heat-resistant adhesive will be low. Therefore, when 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride are used as a mixture, 20 to 80 mol of the tetracarboxylic dianhydride component is used. % Is 3,3 ', 4,4'-biffe
Nyltetracarboxylic dianhydride, preferably 20
~ 70 mol%.

The adhesive of the present invention has, in addition to the above-mentioned structural characteristics of polyimide or polyamic acid, the molecular weight of polyamic acid, ie, logarithmic viscosity (N, N-dimethylacetamide solvent: concentration 0.5 g / 100 ml solvent, 35 g 0.1-3.0dl)
/ g is particularly preferable in the range of 0.5 to 1.5 dl / g from the viewpoint of heat resistance, adhesiveness and workability. This molecular weight can be adjusted by the molar ratio of 4,4′-bis (3-aminophenoxy) biphenyl to the tetracarboxylic dianhydride component.

The adhesive of the present invention can be prepared as a product using the above polyamic acid as described below and put to practical use, and a polyimide obtained by further imidating this polyamic acid is put to practical use as an adhesive. Is done. That is, the above-mentioned polyamic acid, that is, the formula (3) and the formula (4)
Having a structural and compositional feature represented by, and the polyamic acid in N, N-dimethylacetamide at a concentration of 0.5 g / 100
Dissolved in 0.1 ml and the logarithmic viscosity measured at 35 ° C was 0.1-3.0 dl / g
Is thermally and chemically imidized to obtain a polyimide. Imidation is carried out in a conventional manner, i.e., about 100
It may be carried out by heating to 300 ° C. for dehydration and ring closure, or by chemically dehydration and ring closure using an imidizing agent such as acetic anhydride.

The adhesive of the present invention containing the polyamic acid or polyimide thus obtained can be put to practical use in the following general mode.

(1) The present invention is applied as a heat-resistant adhesive consisting essentially of a varnish containing the above-mentioned polyamic acid according to the present invention and a solvent that dissolves this polyamic acid well. The adhesive of this embodiment converts polyamic acid to polyimide by a method such as heating after being applied to an object to be bonded, and exhibits an excellent adhesive effect.

(2) A polyimide processed into a film or powder, for example, is applied as a heat-resistant adhesive substantially made of polyimide. This adhesive is used in such a manner that it is adhered to an object to be adhered, heated, melted and pressed.

(3) The present invention is applied as an adhesive consisting essentially of a varnish containing the polyimide according to the present invention and a solvent that dissolves the polyimide well. The adhesive of this embodiment is used in such a method that, after being applied to an object to be bonded, the solvent is removed by a method such as heating, followed by heat melting and pressure bonding.

In each of the above embodiments, in the case of (1), the varnish containing mainly the polyamic acid and the good solvent for the polyamic acid includes a solution in which the polyamic acid is dissolved in an organic solvent. Usually, as a solvent for dissolving the polyamic acid, a polyamic acid generation reaction solvent is used as it is, and therefore, as a varnish, 4,4′-bis
A reaction product solution containing a polyamic acid obtained by reacting (3-aminophenoxy) biphenyl with 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride. You may. Further, a material containing polyamic acid as a main component and polyimide which is a cyclized product of polyamic acid may be contained therein. Therefore, the solution containing the polyamic acid may be a solution or suspension containing a part of the polyimide.

When a varnish containing such a polyamic acid is used as an adhesive, the varnish is adhered in a thin layer to an adherend to be bonded, and then the adhered adherent is exposed to air. In the required time, heating to about 100 to 300 ° C to remove excess solvent, convert the polyamic acid to a more stable polyimide, and then apply a pressure of 1 to 1000 kg / cm ²
When pressure bonding is performed at a temperature of 400 to 400 ° C. and curing is performed at a temperature of 100 to 400 ° C., the adherend can be firmly bonded.

The adhesive as a polyimide is, for example, substantially a polyimide itself obtained by thermally or chemically dehydrating and cyclizing a polyamic acid to form a film or a powder. The adhesive may contain a part of polyamic acid. When such a substantially polyimide is used, a film or a powder is inserted and adhered between the adherends, and a pressure of 1 to 1000 kg / mm ^{2 and} a pressure of 100 to 4 kg / mm ² are applied.
Pressing at a temperature of 00 ° C. and curing at a temperature of 100 to 400 ° C. can firmly bond the adherend.

Further, in the case of (3), the polyimide and the varnish containing a good solvent for the polyimide mainly include a solution in which the polyimide is dissolved in an organic solvent. As the solvent for dissolving the polyimide, the reaction solvent for the production of polyimide is applied as it is, so in an organic solvent, 4,4'-
A reaction solution containing a polyimide obtained by reacting bis (3-aminophenoxy) biphenyl with 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride. You may. Further, polyimide obtained once may be dissolved again with an organic solvent. Further, the suspension may further contain a polyimide.

When the varnish containing such a polyimide is used as an adhesive, the same operation as in the case where the varnish containing a polyamic acid is used as an adhesive can be performed.

In using the heat-resistant adhesive of the present invention, the adhesive is impregnated into a glass fiber cloth or a carbon fiber cloth by a known method, and the heat-resistant adhesive of the present invention is attached to an adherend. It is also possible to adopt a method in which a glass fiber cloth or a carbon fiber cloth is inserted between the adhesives and then adhered after the application of the conductive adhesive.

It is also possible to use a method in which the surface of the adherend is subjected to chemical and physical treatments and then bonded. Examples of surface treatment methods include chemical etching with an acid or alkali, corona treatment, ultraviolet irradiation, radiation irradiation, dry sand blasting, heat treatment, plasma treatment, polishing treatment, wet sand blast treatment, plating treatment, oxide film treatment, degreasing treatment, and the like. . These methods may be a single method or a combined method.

In using the heat-resistant adhesive of the present invention, the properties of the heat-resistant adhesive of the present invention are not impaired.
It is also possible to add and bond other resins. Other resins to be added include nylons, polyacetal, polycarbonate, polyphenylene oxide, polyethylene terephthalate, polysulfone, polyethersulfone, polyarylate, polyamideimide, polyetherimide, polyetheretherketone, polyimides other than the present invention, Fluororesin, polybismaleimide, epoxy resin and the like.

It is to be noted that one or more solid lubricants, for example, molybdenum disulfide, graphite, boron nitride, lead monoxide, lead powder, and the like can be added to the heat-resistant adhesive of the present invention.

Also, reinforcing materials such as glass fiber, carbon fiber, aromatic polyamide fiber, potassium titanate fiber,
One or more kinds of glass beads or the like can be added.

The heat-resistant adhesive of the present invention has an antioxidant, a heat stabilizer and a heat stabilizer within a range not to impair the object of the present invention.
One or more ordinary additives such as an ultraviolet absorber, a flame retardant, a flame retardant auxiliary, an antistatic agent, and a coloring agent can be added.

[0040]

The present invention will be described in more detail with reference to the following examples. Example 1 In a container equipped with a stirrer reflux condenser and a nitrogen inlet tube, 4,4 ′
-Bis (3-aminophenoxy) biphenyl 36.8 g
(0.1 mol) and 137.6 g of N, N-dimethylacetamide
And at room temperature under a nitrogen atmosphere, 16.57 g (0.076 mol) of pyromellitic dianhydride and 3,3 ′,
5.59 g of 4,4'-biphenyltetracarboxylic dianhydride
(0.019 mol) was added in portions, paying attention to the rise in solution temperature, and the mixture was stirred at room temperature for about 20 hours. The logarithmic viscosity of the polyamic acid thus obtained at 35 ° C. and a 0.5% concentration in N, N-dimethylacetamide solvent is 0.54 d.
1 / g. Kapton 200H (Dupont's company) washed the above polyamic acid adhesive solution with ethanol.
1 ) at 150 ° C for 1 hour in air
After heating and drying at 50 ° C. for 5 hours, a 20 μm thick Inconel foil is overlaid, and at 350 ° C., 100 kg / cm ² , 1
Pressure was applied for 0 minutes to perform pressure bonding. The thickness of the applied adhesive is 25
μm. The 180 ° peel strength of this product is
It was 2.4 kg / cm at room temperature (measurement method conformed to JPCA-BM01). Further, when this was left at room temperature, the daily change of the 180 ° peel adhesive strength was measured. 100 immediately after 180 ° peel adhesion
FIG. 1 shows the relationship between the retention rate and time when the percentage is set to%. Furthermore, when this was measured at a high temperature of 220 ° C., 1.9 kg
/ Cm. Further, after the above polyamic acid solution was cast on a glass plate, it was heated at 150 ° C.
Each was heated at 50 ° C. for 2 hours to obtain a pale yellow transparent polyimide film. The thickness of this polyimide film is about 30
μm. This polyimide film has a tensile strength of 1
It was 5.6 kg / mm ² and the elongation was 90%. (The measurement method is based on ASTH D-882). Its glass transition temperature was as high as 266 ° C. (Based on the TMA penetration method.) A steel plate (cold rolled steel plate, JIS G3141, s) obtained by preheating this polyimide film to 130 ° C
pcc / SP, 25x100x1.6mm)
350 ° C., pressurized between 5 ^{50kg / cm 2, 290kg / cm} 2 and was the (measuring method where the tensile shear adhesive strength using a test piece which was pressed were measured at room temperature, J
According to IS-K6848 and 6850. ). When this was further measured at a high temperature of 220 ° C., it was 220 kg / cm
It was ² .

COMPARATIVE EXAMPLE 1 16.57 g of pyromellitic dianhydride in Example 1
(0.076 mol) and 5.59 g (0.019 mol) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride
To 19.76 g of pyromellitic dianhydride (0.090
Mol) and 1.40 g (4.75 × 10 ⁻³ mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride in the same manner as in Example 1 except that the logarithmic viscosity was 0.56 dl.
/ G of polyamic acid solution was obtained. Using this polyamic acid solution, Kapton2 was prepared in the same manner as in Example 1.
00H was bonded to the Inconel foil, and the 180 ° peel adhesion was measured at room temperature and found to be as low as 0.15 kg / cm ² . In the same manner as in Example 1, the change over time in the retention of the 180 ° peel adhesive strength when left at room temperature was measured. The results are shown in FIG. After the upper polyamic acid solution was cast on a glass plate, a polyimide film having a thickness of 30 μm was obtained in the same manner as in Example 1. The glass transition temperature of this polyimide was 269 ° C.

Comparative Examples 2 to 4 The pyromellitic dianhydride and biphenyltetracarboxylic dianhydride in Example 1 were used in predetermined amounts shown in Table 1, and the diamines shown in Table 1 in Comparative Example 4 were used. Then, adhesion was performed in the same manner as in Example 1 and the evaluation was performed. These results are shown in FIG.

Examples 2 to 4 The polyamic acid solution was prepared in the same manner as in Example 1 except that the amount and composition of the tetracarboxylic anhydride component used were adjusted as shown in Table 1. A test piece was prepared in the same manner as in Example 1 and 180 ° at room temperature and 220 ° C.
The peel adhesion strength and the glass transition temperature of the polyimide film were measured. The results are shown in Example 1 and Comparative Examples 1 to 3.
The results are shown together with the results. It turns out that it has excellent peeling adhesive strength and heat resistance as compared with Comparative Example 1.

Example 5 Logarithmic viscosity 0.54 dl /
Thus, a polyamic acid N, N-dimethylacetamide varnish having a weight of g was obtained. To this, 30.6 g (0.3 mol) of acetic anhydride and 20.2 g (0.2 mol) of triethylamine were added, and the mixture was stirred at 80 ° C. for 4 hours. This reaction solution was discharged into 1000 g of methyl ethyl ketone. After the obtained yellow polyimide powder was further washed with 1000 g of methyl ethyl ketone, it was dried under reduced pressure at 200 ° C. for 8 hours. The 35 ° C. logarithmic viscosity of the obtained polyimide powder was 0.53 dl / g at a concentration of 0.5% in a mixed solvent of p-chlorophenol and phenol (weight ratio 9: 1). The glass transition temperature by DSC was 267 ° C. Using this Horiimido powder, just as carrying this polyimide powder Kapton200H Example 1, further superimposed Inconel foil 20μm thickness, 100 kg ^/ cm 2 at 350 ° C., 10
Bonded by pressing for a minute. The thickness of the applied adhesive is 25μ
m. Its 180 ° peel adhesive strength is 2.3 kg / cm ² at room temperature and 1.8 kg at high temperature of 220 ° C.
/ Cm ² .

Example 6 Polyimide powder 1 obtained in exactly the same manner as in Example 5
0 g was charged to 90 g of m-cresol with stirring. This was heated to 160 ° C. and stirred for 1 hour to completely dissolve,
A polyimide varnish was obtained. This polyimide varnish was applied to Kapton 200H washed with ethanol and dried in air at 200 ° C. for 2 hours, and then a 20 μm thick Inconel foil was overlaid at 350 ° C. and 100 kg / cm ² , 1
Pressure was applied for 0 minutes to perform pressure bonding. The thickness of the applied adhesive is 25
μm. Its 180 ° peel adhesion was 2.5 kg / cm ² at room temperature and 2.0 kg / cm ² at a high temperature of 220 ° C.

[0046]

[Table 1]

[0047]

The heat-resistant adhesive of the present invention comprises 4,4'-bis (3-aminophenoxy) biphenyl as an aromatic diamine component, and pyromellitic dianhydride and 3,3'-tetracarboxylic dianhydride. It is characterized by using 3 ', 4,4'-biphenyltetracarboxylic dianhydride and having particularly excellent peel adhesion strength and heat resistance.

[Brief description of the drawings]

FIG. 1 shows the performance of the polyamic acid obtained in Examples and Comparative Examples as an adhesive by measuring the change over time of the 180-degree peel adhesive strength.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-68817 (JP, A) JP-A-62-48782 (JP, A) JP-A-61-143478 (JP, A) JP-A-62-1988 104840 (JP, A) JP-A-62-143435 (JP, A) JP-A-3-192177 (JP, A) JP-A-4-233944 (JP, A) JP-A-2-234911 (JP, A) JP-A-2-210713 (JP, A) JP-A-2-209924 (JP, A) JP-A-2-151629 (JP, A) JP-A-62-208690 (JP, A) International publication 91/9900 (JP / A) WO, A1) (58) Fields surveyed (Int. Cl. ⁷ , DB name) C09J 1/00-201/10 C09D 1/00-201/10 C08G 73/10 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] In a polymer molecule , a compound represented by the formula (1): 20 to 80 mol% of the structural unit represented by the formula : and the formula (2) A heat-resistant adhesive comprising a polyimide having a structural unit represented by the formula: 20 to 80 mol% . 2. In a polymer molecule , a compound represented by the formula (3): 20 to 80 mol% of a structural unit represented by the formula: and the formula (4): A polyimide-based heat-resistant adhesive comprising a polyamic acid having a structural unit represented by the formula: 20 to 80 mol% . 3. A polyamic acid, wherein the polyamic acid is N,
0.5g / 100ml in N-dimethylacetamide
The heat-resistant adhesive according to claim 2, wherein the adhesive has a logarithmic viscosity of 0.1 to 3.0 dl / g when measured at 35 ° C. 4. In a polymer molecule , a compound represented by the formula (3): 20 to 80 mol% of the structural unit represented by the formula: and the formula (4): Is a polyamic acid having a structural unit represented by 20 to 80 mol% , and the polyamic acid is dissolved in N, N-dimethylacetamide at a concentration of 0.5 g / 100 ml and measured at 35 ° C. A heat-resistant adhesive comprising a polyimide obtained by thermally and chemically imidizing a polyamic acid having a logarithmic viscosity of 0.1 to 3.0 dl / g. 5. A varnish containing the heat-resistant adhesive according to claim 1. 6. A varnish containing the heat-resistant adhesive according to claim 2.