JPS61291669A - Heat-resistant adhesive - Google Patents

Abstract

PURPOSE:To titled novel adhesive, consisting of a polymer having specific repeating units and capable of exhibiting powerful adheasive 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 (Z is formula II or III). The polymer having the repeating units expressed by formula I can be proeuced by reacting 2, 2-bis [4-(3-aminophenoxy)] phenylpropane expressed by formula IV with pyromellitic acid dianhydride and, as necessary, cylizing the resultant reaction product 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 having strong adhesive strength and excellent heat resistance.

[Conventional technology]

Heat-resistant adhesives made of organic synthetic polymers have long 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 above-mentioned adhesives, adhesives such as fluororesin, polyamideimide, silicone, epoxy novolank, epoxy acrylic, nitrile rubber, phenol, and 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, so they are not completely satisfactory.

On the other hand, polyimide adhesives are used as adhesives with excellent heat resistance. 065.3
No. 45) is known, but when a normal polyimide resin is completely cyclized and becomes a polyimide, it has very poor melt fluidity, making it difficult to use.

[Problem that the invention seeks to solve]

The object of the present invention is to provide a novel heat-resistant adhesive that exhibits high melt flowability and strong adhesive properties when used as an adhesive, and that does not lose adhesive strength during or after use even when used at high temperatures. Our goal is to provide adhesives.

[Means for solving problems]

The inventors of the present invention conducted intensive studies to achieve the above object, and as a result, discovered a new heat-resistant adhesive.

That is, the present invention is a heat-resistant adhesive made of a regular polymer having a repeating unit represented by (wherein, Z represents OO).

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 polymer that is the heat-resistant adhesive of the present invention has the formula (
n) diamine represented by H3 (II), i.e. 2,2-bis(4-(3-
Polyamic acid and/or obtained by reacting aminophenoxy)phenyl)propane and pyromellitic dianhydride
Alternatively, it is a polyimide obtained by further cyclodehydration of this.

The polyimide resin comprising 2,2-bis(4-(3-aminophenoxy)phenyl)propane and bilometic acid dianhydride according to the present invention has recently been reported as a melt-fusible polyimide (especially Kaisho 59-170, 1
22), L.Although the same application describes the polymer structure, there is no specific description, especially no description of the physical properties of the polymer.

Moreover, 2,2-bis(4-(3-
For aminophenoxy)phenyl)propane, m
- It is only a simple statement that a dinitro compound can be obtained by the reaction of chloronitrobenzene and 2,2-bis(4-hydroxyphenyl)propane, and then it can be produced by reduction, and the physical properties that recognize the structure such as melting point are not explained. There is no description at all.

On the other hand, 2,2-bis(4-(3-aminophenoxy)
It has been reported that an organic solvent-soluble polyimide resin containing phenyl)propane and pyromellitic anhydride as one of the diamine and tetracarboxylic dianhydride components is useful as an adhesive for flexible printed circuit boards. (Japanese Unexamined Patent Publication No. 58-157.190). However, in this method, 2°2-bis(4-(3-aminophenoxy)phenyl)propane is only disclosed as one type of many diamine components. Although pyromellitic dianhydride is mentioned as the tetracarboxylic anhydride used in this method, the tetracarboxylic anhydride used is 3.3'.

4.4'-benzophenone tetracarboxylic dianhydride,
3.3', 4.4'-diphenyl ether tetracarboxylic dianhydride, 2.2-bis(3,4-dicarboxyphenyl)-1,1,I3.3.3-hexafluoropropane dianhydride Both have a structure in which two phthalic anhydrides are linked by an organic group or oxygen, and the polyimide resins obtained from these acid anhydrides include phenol, cresol, halophenols, nitrobenzene, sulfolane, It is characterized by being soluble in organic solvents such as N-methyl-2-pyrrolidone and N,N-dimethylacetamide.

Generally, polyimide resins using pyromellitic dianhydride do not have adhesive strength, and therefore, it has not been known to use polyimide resins using pyromellitic dianhydride as an adhesive. For example, when 3.3'-diaminobenzophenone is used as a diamine component, 3.3',
Polyimide resins obtained from 4.4'-benzophenone tetracarboxylic dianhydride and 3.3', 4.4'-diphenyl ether tetracarboxylic dianhydride both have strong adhesive strength, but biromerino I- It is known that when acid dianhydrides are used, polyimide resins exhibit no adhesive properties [T, St, CIa
ir et al., Polymer Preprint, 16.
538-543 (I975)].

Based on these technical backgrounds, the present inventors conducted extensive studies on polyimide resins using pyromellitic dianhydride, which is industrially advantageously obtained as a raw material, as a tetracarboxylic dianhydride component, and developed 2,2-bis The present invention was achieved by discovering that a polyamic acid and polyimide in which (4-(3-aminophenoxy)phenyl)propane is combined as a diamine component has unexpected melt flowability and strong adhesive strength.

The polyimide obtained by heating or chemically dehydrating and cyclizing the polyamic acid of the present invention can be obtained from the above-mentioned invention (Japanese Unexamined Patent Publication No. 58-15
7.190), it does not dissolve in organic solvents such as phenols, nitrobenzene, and aprotic polar solvents.

That is, the polyimide resin of the present invention is completely insoluble in various organic solvents, and therefore has extremely excellent chemical resistance.

In addition, in the present invention, the diamine component is 2,2-bis(4-
(3-aminophenoxy)phenyl)propane is used, but by the way, 2,2- which is a substituted positional isomer of the amine group
The polymer obtained from bis(4-(4-aminophenoxy)phenyl)propane and pyromellitic dianhydride is
In contrast, the polymer of the present invention has excellent heat-resistant adhesive properties, whereas its adhesive strength is extremely low.

The reaction for producing polyamic acid described above is usually carried out in an organic solvent. Examples of the organic solvent used in this reaction include N,N-dimethylformamide and N.

N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, N
-Methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1.2
-dimethoxyethane, bis(2-methoxyethyl)ether, lI2-bis(2-methoxyethoxy)ethane,
Bis(2-(2-methoxyethoxy)ethyl)ether, tetrahydrofuran, 1.3-dioxane, 1.4
-Dioxane, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethylurea, hexamethylphosphoramide, etc. 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 and reaction temperature, but it is a sufficient time for polyamic acid to be produced, and is usually 4.
~24 hours.

A polyamic acid is obtained having a repeating unit of formula (I) in which Z is odor.

Furthermore, the obtained polyamic acid is dehydrated by heating at 100 to 300°C or by chemical treatment with a dehydrating agent such as acetic anhydride to form a polyamic acid having a repeating unit of formula (r), which is the following formula (I) % formula % Polyimide is obtained.

When the thus obtained polymer is used as an adhesive, there are two main categories: (I) when it is used as an adhesive solution mainly containing the polyamic acid, and (2) when the 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. ) Phenyl) propane and pyromellitic dianhydride may be reacted. 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 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 heat. The solvent is removed and the polyamic acid adhesive is converted to a more stable polyimide, which is overlaid with another adherend and then crimped at a pressure of 1 to 1,00 Q kg/am2 and a temperature of 50 to 400 °C. By curing at a temperature of 100 to 400° C., objects to be bonded 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/cm2 and 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.

[Examples] Hereinafter, the present invention will be explained in detail with reference to Examples, Comparative Examples, Synthesis Examples, and Reference Examples.

[Reference example]

An Ulmann reaction in which m-chloronyl-lobenzene and 2,2-bis(4-hydroxyphenyl)propane are condensed in an amine solvent under a copper catalyst, and a heating reaction in an aprotic polar solvent in the presence of a base. However, the reaction did not proceed at all with either method.
The desired 2,2-bis(4-(3-aminophenoxy)phenyl)propane was not obtained.

[Synthesis example]

2.2-Bis(4-(3-aminophenoxy)phenyl)propane was synthesized as follows.

2.2-bis(4-hydroxyphenyl)propane 85
．． 6 g (0.38 mol), m-dinitrobenzene 1
51.2 g (0.9 mol), potassium carbonate 124.
6 g and N,N-dimethylformamide 660 mk
was charged and reacted at 145 to 150°C for 10 hours. After the reaction was completed, the mixture was cooled and the solids were filtered, and the solvent was removed from the filtrate by distillation under reduced pressure. The mixture was cooled to 65° C., charged with 450 mA of methanol, and stirred for 1.0 hour. The crystals are filtered, washed with water, methanol, and dried to give 2,2-bis(
Yellowish brown crystals of 4-(3-nitrophenoxy)phenyl)propane were obtained. Yield 164.8 g (Yield 93゜5
%). The crude crystals were recrystallized using methyl cellosolve to obtain a pure product.

Pale yellow prismatic crystal mp 111-113℃CHN) Elemental analysis Calculated value (%) 68.93 4.71 5
．． 96 analysis value (%) 69.05 4.65 5.9
4*)C2? N22 N2 0g MS: 470 (M), 455 (M-CH3)”
I R (KB r, cm'): 1520 and 1
340 (No2 group) 1240 (ether bond) 1.000 ml In a sealed glass container, add 1 crude 2,2-bis(4-(3-nitrophenoxy)phenyl)propane.
00 g (0.21 mol) with 5% Pd/C5, Og, methyl cellosolve 300 mA. 60-6
Hydrogen is introduced at 5°C with vigorous stirring. Absorption stopped in 8 hours and the reaction was completed.

After cooling and filtering to remove the catalyst, methyl cellosolve 150
1 is distilled off. Add 270 g of 20% hydrochloric acid, and further add 30 g of common salt, and cool to 20 to 25°C while stirring to precipitate crystals. This is filtered and neutralized with aqueous ammonia in 30% isopropanol to precipitate crystals. This was filtered, washed with water, dried, and then recrystallized from a mixed solvent of benzene and n-hexane.
-aminophenoxy)phenyl)propane was obtained. Yield: 69.2 g (yield: 80%).

Colorless crystal m p , 106-108°C Purity 9
9.5% (by high performance liquid chromatography) CHN X) Elemental analysis, calculated value (%) 79.02 6.34
6.83 Analysis value (%) 79.21 6.40 6.
71*) c, 7H, LG N202 M5: 410 (M), 395 (M-CH
3) I R (KB r, cm-'): 346
0 and 3370 (NH2 group) 1220 (ether bond) Example-1 2.2-bis(4-(3-aminophenoxy)phenyl)propane 41 was placed in a container equipped with a stirrer, a reflux condenser, and a nitrogen introduction tube. .0g (0.1 mol), N, N
- 188.4 g of dimethylacetamide was charged, cooled to around 0°C, and 17.44 g (0.08 mol) of pyromellitic dianhydride was divided into 4 portions under a nitrogen atmosphere while being careful not to increase the solution temperature. and stirred at around 0°C for about 2 hours. Next, the above solution was returned to room temperature, and 4.36 g (0.02 mol) of pyromellitic dianhydride was added under a nitrogen atmosphere, followed by stirring for about 20 hours under a nitrogen atmosphere. The polyamic acid thus obtained was heated at 35°C, N,
The logarithmic viscosity at 0.5% concentration in N-dimethylacetamide solvent was 15 dl/g. After casting the above polyamic acid solution on a glass plate, it was heated at 100°C and 20”C.
and 300'C for 1 hour each to obtain a polyimide film. The glass transition temperature of this polyimide film is 228°C (TMA Needleman Corporation. The same shall apply hereinafter), 5
The % thermal decomposition temperature was 515°C (according to DTA-TO. The same applies hereinafter).

This polyimide film was preheated to 130"C to form a cold rolled steel plate (JIS G3141.5PCC/S
D, 25X 100

The tensile shear adhesive strength of this product at room temperature is 300 kg/
When this was further measured at a high temperature of 240'C, it was found to be 180 kg/cI112. (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)Propane was used in the same manner as in Example 1 at 35°C, N
, a polyamic acid with a logarithmic viscosity of 1.70 dl/H at 0.5% concentration in N-dimethylacetamide solvent was obtained. After casting this polyamic acid solution on a glass plate, 10
Polyimide films were obtained by heating at 0°C, 200°C and 300°C for 1 hour each.

The glass transition temperature of this polyimide film is 330°C.
The 5% pyrolysis temperature was 502°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 is 8
It was 4 kg/■2. When this was further measured at a high temperature of 240° C., it was found to be 57 kg/cm 2 .

Example-2 The polyamic acid adhesive solution obtained in Example-1 was applied to a cold-rolled steel plate that had been washed with trichlorethylene (same as in Example-1. The same applies hereinafter), and heated at 100°C for 1 hour at 220°C.
After heating and drying at ``C'' for 1 hour, the cold rolled steel plate was placed and
Pressure was applied at 40° C. and 120 kg/cm” for 5 minutes. The thickness of the applied adhesive was 35 microns.

The tensile shear adhesive strength of this product is 305 kg/cf at room temperature.
It was lI2. When this was further measured at a high temperature of 240°C, it was found to be 180 kg/cm 2 .

Examples 3 to 5 The reaction was carried out in the same manner as in Example 1, except that the amount of pyromellitic anhydride was changed, and the results shown in Table 1 were obtained. In addition, Table=1 shows Examples-1 and 2.
The results of Comparative Example-1 are also described.

Comparative Example-2 The reaction was carried out in the same manner as Comparative Example-1 except that the amount of pyromellitic anhydride was changed.

The results are shown in Table-1.

In the solubility test at room temperature and 1% by weight, the polyimide films obtained in Examples 1 to 5 and Comparative Examples 1 to 2 showed phenol, cresol, xylenol, 0-chlorophenol, p-tetrachlorophenol, p- -bromophenol, 2
．． 4-dichlorophenol, 2,4.6-trichlorophenol, nitrobenzene, dimethyl sulfoxide,
trifluoroacetic acid, N,N-dimethylformamide,
N,N-dimethylacetamide, hexamethylphosphoramide, sulfolane, methylsulfolane, N-methyl-
It was insoluble in 2-pyrrolidone.

Example-6 75.36 g of the N,N-dimethylacetamide melt of polyamic acid obtained in Example-3 was charged into a container equipped with a stirrer, a reflux condenser, and a nitrogen introduction pipe, and N,N-
It was diluted by adding 50.24 g of dimethylacetamide.

Add 12.3 g (0.12 mol) of acetic anhydride to the above solution.
A mixed solution of 4.25 g (0.04 mol) of triethylamine and triethylamine was added dropwise over 30 minutes. The solution began to become cloudy after the completion of the dropwise addition, and a pale yellow polymer began to precipitate 15 minutes after the completion of the dropwise addition. After stirring for another 2 hours, filter and add water 2
00g, dried under reduced pressure at 150°C for 8 hours, 17.
2 g of pale yellow powder was obtained.

The glass transition temperature of this powder measured by DSC is 227°C.
, the 5% decomposition temperature was 512°C. FIG. 1 shows an infrared absorption spectrum diagram of the obtained powder.

In this spectrum diagram, the characteristic absorption band of imide is 178
Significant absorption was observed near 0 cm' and 1720 cm-'. Using this polyimide powder, a cold rolled steel plate was crimped under the same conditions as in Example-1. The tensile shear adhesive strength of this material at room temperature was 315 kg/.2, and when this was further measured at a high temperature of 240°C, it was 180 kg.
/an2.

The obtained polyimide powder was similarly insoluble in the solvents described after Comparative Example-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, especially at high temperatures.

[Brief explanation of drawings]

FIG. 1 is an example of an infrared absorption spectrum diagram of polyimide powder used in the heat-resistant adhesive of the present invention.

Claims (1)

[Claims] Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, Z 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