JPH044231A - Heat-resistant film with low coefficient of linear expansion and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title film excellent in resistance to heat and combustion, useful as a protective film, etc., by stretching under a specified load a heated polyamic acid film and applying specified vibration on said film along with curing under heating. CONSTITUTION:In producing a film of a heat-resistant resin, a polyamic acid film heated at 60-150 deg.C is stretched under a load of 2-200g/mm<2> and cured under heating while applying a vibration of 5-500Hz on said film, thus obtaining the objective film with a coefficient of linear expansion of -5 to 5ppm. Said heat- resistant resin is pref. a polyimide, which can be prepared by mixing under agitation (A) a polyamic acid solution from 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine and (B) a second polyamic acid solution from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether followed by curing under heating.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to the production of heat-resistant resin films used for electrical insulating materials, protective films, heat insulating materials, etc. A heat-resistant film with a low linear expansion coefficient, which is obtained by pulling a polyamic acid film obtained by heating with a load of 2 to 200 g/mm2 and heat-curing it while applying vibrations of 5 to 500 Hz to the film. and its manufacturing method.

(Prior Art) Conventionally, in order to obtain a film of a heat-resistant resin with a low coefficient of linear expansion, a method of uniaxially or biaxially stretching has been used in the film manufacturing process.

However, the films obtained by this method have problems such as non-uniform thickness and distribution of molecular orientation in the width direction due to stretching, so it was necessary to highly control the manufacturing conditions. .

Furthermore, although the demand for films with a low coefficient of thermal expansion has been increasing in recent years, it has been difficult to obtain a sufficiently uniform film with a low coefficient of thermal expansion using the methods described above.

(Problems to be Solved by the Invention) The present invention has been made as a result of intensive studies aimed at overcoming the above-mentioned drawbacks. As a result, the heat-resistant resin film produced using the method specified in the present invention has a very high coefficient of linear expansion. Based on this finding, the present invention was completed.

(Means for Solving the Problems) The present invention provides the following features in producing a heat-resistant resin film:
A low wire film obtained by heating a polyamic acid film at a temperature of 60 to 150°C is stretched under a load of 2 to 200 g/mm2, and heat-cured while applying vibrations of 5 to 500 Hz to the film. A heat-resistant expansion film and a method for producing the same.

(Function) The heat-resistant resin used in the present invention only needs to have film-forming ability, and the following polyimides suit the purpose.

That is, the tetracarboxylic dianhydride component and the diamine component are mixed at an acid component/amine component (molar ratio) of 0.90 to 1.
．． When reacting as 00, 3.3°, 4,4°
- A polyamic acid solution (A) obtained by reacting biphenyltetracarboxylic dianhydride and paraphenylene diamine, and a polyamic acid solution (A) obtained by reacting pyromellitic dianhydride and 4.4°-diaminodiphenyl ether. acid solution (B), A/B=45155-1001
It is a polyimide obtained by heating and curing a polyamic acid mixed solution obtained by mixing and stirring at a ratio of 0.

The method for producing a low linear expansion coefficient film of the present invention is to first directly cast the above-mentioned polyamic acid solution onto a substrate such as a glass plate, and form a resin layer into a film but not completely cure. A polyimide film is obtained by heating and curing the polyamic acid film obtained by heating at a temperature of 100° C. continuously from 100° C. to 350° C. while applying low frequency vibration in the l-axis or biaxial direction at λ.

The tetracarboxylic dianhydride used in the present invention is 3.3
',4,4'-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, but other acids such as 2.3.3°4-biphenyltetracarboxylic dianhydride, 3, 3°, 4.4'-benzophenonetetracarboxylic dianhydride, 3.3°, 4.4°-P-terphenyltetracarboxylic dianhydride, 2.3.6.7-naphthalenetetracarboxylic dianhydride Anhydride, 3.3°, 4.4-benzophenonetetracarboxylic dianhydride, 3.3°, 4.
4°-P-terphenyltetracarboxylic dianhydride, 4
．． 4°-hexafluoroisopropylidene bis (phthalic anhydride) and the like can also be used in combination.

The diamines used in the present invention include phenylenediamine and 4,4°-diaminodiphenyl ether, but other amines such as 4.4°-diaminodiphenylmethane, 3.3°-dimethylbenzidine, 4,4°-diamino- P-terphenyl, 4,4°-diamino-P-quarterphenyl, 2,8-diaminodiphenylene oxide, etc. can also be used in combination.

The reaction between the tetracarboxylic dianhydride component and the diamine component is preferably carried out at an acid component/amine component (molar ratio) of 0.90 to 1.00. If it is lower than 0.90, the degree of polymerization will not increase and the reaction after curing will be Poor film properties.

If it is larger than 1.00, gas will be generated during curing, making it impossible to obtain a smooth film.

The reaction is usually carried out in an organic polar solvent that does not react with the tetracarboxylic dianhydride and diamines.In addition to being inert to the reaction system and being a solvent for the product, this organic polar solvent The solvent must be a good solvent for at least one, preferably both, of the reaction components;
Typical solvents of this type include N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfone, dimethylsulfoxide, and N-methyl-2-
There are pyrrolidone and the like, and these solvents are used alone or in combination. In addition, non-polar solvents such as benzene, dioxane, xylene, toluene, and cyclohexane are also used in combination as solvents, as dispersion media for raw materials, reaction regulators, volatilization regulators from products, film smoothing agents, etc. used.

It is generally preferable to carry out the reaction under anhydrous conditions, since the tetracarboxylic dianhydride may be ring-opened by water, becoming inactivated, and terminating the reaction. Therefore, it is necessary to remove both the moisture in the raw materials and the moisture in the solvent. However, on the other hand, water is intentionally added in order to adjust the progress of the reaction and control the degree of resin polymerization.

Further, the reaction is preferably carried out in an inert gas atmosphere in order to prevent oxidation of the diamines. Dry nitrogen gas is generally used as the inert gas.

The synthesis reaction of the polyimide resin used in the present invention is carried out in the following manner. That is, a polyamic acid (referred to as A) obtained by reacting 3,3°, 4.4°-biphenyltetracarboxylic dianhydride and paraphenylenediamine, pyromellitic dianhydride, and 4.4° This is a method of obtaining a polyamic acid (referred to as C) by mixing and stirring a polyamic acid obtained by reacting with diaminodiphenyl ether (referred to as B) at a ratio of A/B = 45155 to 10010.

When the ratio of A is less than the above-mentioned ratio, the coefficient of linear expansion will not become sufficiently small.

The reaction temperature for synthesizing A and B and mixing them to obtain C is preferably 0 to 100°C.

This is because if the temperature is below 0°C, the reaction rate will be slow, and if it is above 100°C, the ring-closing reaction and depolymerization reaction of the produced polyamic acid will start. Usually, the reaction is carried out at around 20°C.

When using the polyamic acid product produced according to the present invention, various silane coupling agents, borane coupling agents, titanate coupling agents 1, aluminum coupling agents and other chelate-based adhesion/adhesion improvers can be used. Various solvents, flow agents, etc. may be added, and ductility agents and viscosity modifiers such as rubber and low-molecular epoxy, polyamideimide, polyetherimide, polyesterimide, and other polyamic acids may also be added. A small amount of fillers such as talc, mica, quartz powder, colorants such as phthalocyanine blue, flame retardants such as tetrabromophenylmethane, and flame retardant aids such as antimony trioxide may be added. .

The polyamic acid film used in the present invention is produced by directly casting the above-mentioned polyamic acid solution onto a base material such as a glass plate, so that the resin layer forms a film but does not completely cure.
The material heated to 0-150''C is used.

At temperatures below 60°C, the solvent does not evaporate sufficiently and it is difficult to obtain a film. At concentrations above 150"C, curing progresses more than necessary, and the coefficient of linear expansion is insufficient even when heated with vibration. does not become smaller.

The base material used in the production of polyamic acid film in the present invention is a glass plate, but aluminum plates, nickel plates, stainless steel plates, etc. can also be used, and in the case of continuous production, stainless steel plates can also be used. Use a drum.

Next, the obtained polyamic acid film is fixed in uniaxial or biaxial directions with a low frequency vibrator, and 2 to 200 g/
It is pulled under a load of mm2 and heated and cured while being excited at a vibration frequency of 5 to 5ooH2.

If the tensile load is less than 2g, the film will sag and vibrations cannot be transmitted sufficiently, and if it is more than 200g, the film will stretch during heating and its dimensions will change before and after curing.

The vibration frequency may be from 5 to 500 Hz, but if the frequency is less than 5H2 or more than 500 Hz, the coefficient of linear expansion will not become sufficiently small.

It is preferable to gradually increase the heating from a low temperature.

For example, from 100℃ to 350℃. Heat continuously for 5 hours or more. 0. If the time is less than 5 hours, depending on the film thickness, solvent removal may be insufficient or imide ring closure may be insufficient, resulting in insufficient properties. For example, at 100℃ for 30 minutes, then at 150℃ for 30 minutes.
minutes, 30 minutes at 200℃, 30 minutes at 250℃ 300℃
The temperature may be raised stepwise, such as 30 minutes at 350°C and 20 minutes at 350°C.

The low frequency vibration device used in the present invention is generally of a hydraulically driven type, but other types can also be used as long as they satisfy the above vibration frequency.

(Example 1) 108 g of purified anhydrous para-phenylenediamine was placed in a four-separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a dry nitrogen gas inlet, and anhydrous N-methyl-2- A mixed solvent of 90% by weight of pyrrolidone and 10% by weight of toluene was added and dissolved in an amount sufficient to make the solid content ratio in the total raw materials 20% by weight. Dry nitrogen gas was allowed to flow throughout the reaction from the preparatory stage to the product removal. Then purified anhydrous 3
294 g of ゜3°, 4.4°-biphenyltetracarboxylic dianhydride was added little by little while stirring, but since it was an exothermic reaction, cold water of about 15°C was circulated in an external water tank to cool it. . After addition, set the internal temperature to 20 °C,
After stirring for 5 hours to complete the reaction, the polyamic acid solution (A
) was obtained. Next, 200 g of anhydrous 4.4°-diaminodiphenyl ether and 218 g of purified anhydrous pyromellitic dianhydride were reacted using the same apparatus and method as above to obtain a polyamic acid (referred to as B). Next, A and B were mixed and stirred so that the molar ratio was A/B=60/40. The product obtained is a clear yellow, extremely viscous polyamic acid solution with a 0.0% concentration in N-methyl-2-pyrrolidone. The intrinsic viscosity of a 5% by weight solution is 0.81 (30°C)
This polyamic acid solution was cast onto a glass plate and then placed in a dryer at 80°C for 2 hours to produce a polyamic acid film.

A low-frequency vibrator was fixed to the polyamic acid film produced in this way, and the film was pulled under a load of 20 g/mm2 and heated from 150°C to 350°C while applying 30Hz vibration.
The temperature was raised over 2 hours to obtain a polyimide film.

The polyimide film produced in this manner had a coefficient of linear expansion of 12 ppm, and was also excellent in heat resistance and flame resistance.

(Example 2) Using the same apparatus and method as in Example 1, a polyamic acid solution (referred to as A) consisting of paraphenylene diamine and 3.3°, 4,4-biphenyltetracarboxylic dianhydride,
A polyamic acid solution (referred to as B) consisting of 4,4'-diaminodiphenyl ether and pyromellitic dianhydride was synthesized. Next, A and B were mixed and stirred so that the molar ratio was 70/30.

The product had an intrinsic viscosity of 0.90. This polyamic acid solution was cast onto a glass plate and placed in a dryer at 100°C for 1 hour to obtain a polyamic acid film.

The polyamic acid film produced in this way was fixed with a low-frequency vibrator, pulled under a load of 100 g/mm2, and heated from 150°C to 350°C while applying 400Hz vibration.
The temperature was continuously raised to ℃ over 1 hour and 30 minutes to obtain a polyimide film.

The polyimide film produced in this manner had a coefficient of linear expansion of 3 ppm and was excellent in heat resistance and flame resistance.

(Comparative Example 1) A polyamic acid solution prepared using the same apparatus and method as in Example 1 was directly cast onto a glass plate, and heated at 170° C. for 1 hour to obtain a film. The film thus obtained was fixed with a low-frequency vibrator, pulled under a load of 30 g/mm2, and subjected to vibrations of 30 Hz.
The temperature was raised from 50°C to 350°C over 2 hours to obtain a polyimide film.

The polyimide film produced in this way had a high coefficient of linear expansion of 21 ppm.

(Comparative Example 2) Using the same apparatus and method as in Example 1, a polyamic acid solution (referred to as A) consisting of paraphenylene diamine and 3.3°, 4,4-biphenyltetracarboxylic dianhydride,
4. A polyamic acid solution (referred to as B) consisting of 4°-diaminodiphenyl ether and pyromellitic dianhydride was synthesized. Next, A and B were mixed and stirred so that the molar ratio was 35/65.

This polyamic acid solution was cast onto a glass plate and then placed in a dryer and heated at 100°C for 1 hour to obtain a polyamic acid film.

The polyamic acid film obtained in this way was fixed with a low frequency vibrator, pulled under a load of 100 g/mm2, and heated from 150'C to 350°C over 2 hours without adding vibration, to form a polyimide film. I got it.

The polyimide film produced in this manner had a linear expansion coefficient as high as 17 ppm.

(Comparative Example 3) Using the same apparatus and method as in Example 1, a polyamic acid solution (referred to as A) consisting of paraphenylene diamine and 3,3°, 4,4-biphenyltetracarboxylic dianhydride,
4. A polyamic acid solution (referred to as B) consisting of 4°-diaminodiphenyl ether and pyromellitic dianhydride was synthesized. Next, A and B were mixed and stirred so that the molar ratio was 60/40.

This polyamic acid solution was cast onto a glass plate and placed in a dryer at 100°C for 1 hour to obtain a polyamic acid film.

The polyamic acid film produced in this way was fixed with a low frequency vibrator and pulled under a load of 50 g/mm2.
150℃ to 350℃ while applying 700Hz vibration
The temperature was raised continuously over 1 hour and 30 minutes to obtain a polyimide film.

The polyimide film produced in this manner had a linear expansion coefficient as high as 20 ppm.

(Comparative Example 4) Using the same apparatus and method as in Example 1, a polyamic acid solution (referred to as A) consisting of paraphenylene diamine and 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 4 .4°-Diamino diphenyl ether and pyromellitic dianhydride polyamic acid solution (referred to as B)
was synthesized. Next, A and B were mixed and stirred so that the molar ratio was 60/40.

This polyamic acid solution was cast onto a glass plate and placed in a dryer at 100°C for 1 hour to obtain a polyamic acid film.

The polyamic acid film produced in this way was fixed with a low-frequency vibrator, pulled under a load of Ig/mrn', and heated from 150°C to 350°C while applying 120Hz vibration.
The temperature was continuously raised to ℃ over 1 hour and 30 minutes to obtain a polyimide film.

The polyimide film produced in this manner had a linear expansion coefficient as high as 18 ppm.

(Effects of the Invention) The polyimide film produced by the method of the present invention had a low coefficient of linear expansion, excellent heat resistance and flame resistance, and excellent electrical and mechanical properties.

The heat-resistant film with a low coefficient of linear expansion obtained by the present invention can also be used as insulation for flexible printed circuit boards and motors, various protective films, base films for magnetic tapes and floppy discs, adhesive tapes, and heat insulating materials.

Claims (2)

[Claims] (1) When producing a film of heat-resistant resin, 60
The polyamic acid film obtained by heating at a temperature of ~150°C was pulled under a load of 2 to 200 g/mm^2,
A linear expansion coefficient of -5 to 5 ppm obtained by heating and curing the film while applying vibrations of 5 to 500 Hz.
heat-resistant film and its manufacturing method. (2) The heat-resistant resin contains a tetracarboxylic dianhydride component and a diamine component, and the acid component/amine component (molar ratio) is 0.
．． 90 to 1.00 when reacting, 3,3'
, 4,4'-biphenyltetracarboxylic dianhydride and paraphenylenediamine, and a polyamic acid solution (A) obtained by reacting pyromellitic dianhydride and 4,4'-biphenyltetracarboxylic dianhydride.
'-diaminodiphenyl ether and the polyamic acid solution (B) obtained by reacting with A/B=45/55~
The heat-resistant film according to claim 1, which is a polyimide obtained by heating and curing a polyamic acid mixed solution obtained by mixing and stirring at a ratio of 100/0.