JPH09208823A - Powdery polyimide composite material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powdery polyimide composite material which contains a clay mineral homogeneously dispersed therein and gives a molding excellent in dimensional stability and to provide a process for producing the same.

SOLUTION: This powdery material comprises a polyimide and a minute org.-modified clay mineral dispersed therein and is prepd. by a process comprising a mixing step wherein a polyimide intermediate polymer and the clay mineral are dissolved and dispersed in an aprotic polar solvent to give a slurried mixture and a powdering step wherein the slurried mixture is spray dried to form a finely powdered polyimide-clay hybrid comprising a polyimide resin and the mineral dispersed therein. Since the mineral disperses homogeneously in the polyimide, a molding with a low coefficient of thermal expansion can be easily obtd. from the composite powder.

COPYRIGHT: (C)1997,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyimide composite material powder and a method for producing the same, more specifically, a powder obtained by dispersing organic clay mineral in a polyimide resin to obtain a polyimide composite material molded article excellent in dimensional stability. The present invention relates to a raw material powder and a manufacturing method thereof.

[0002]

2. Description of the Related Art Polyimide has excellent thermal properties, mechanical properties, electrical insulation properties, chemical resistance, etc.
It is suitable for applications such as flexible printed boards, electric motor insulators, and wire coatings, but in practical use, it has problems such as high gas permeability and high thermal expansion coefficient.

Regarding the polyimide molded article, JP-A-1-
292035 discloses that a polyamic acid, which is an intermediate polymer of polyimide, is synthesized in a basic solvent (pyridine or β-picoline), and then contacted and precipitated with a poor solvent for polyamic acid (acetone) to form fine and fine particles. There is a disclosure of a method of forming an amorphous polyamic acid powder, and then subjecting the obtained powder to a polyimide powder state by a thermal cyclization reaction, and compressing / sintering this to obtain a resin molded product. Further, there is a disclosure that when a carbonaceous material such as graphite is used as a filler in the polyimide powder, the abrasion resistance is improved, but there is no description to improve the resin characteristics by adding another inorganic filler.

On the other hand, as a polyimide composite material, polyamic acid, which is an intermediate polymer of polyimide, and clay organically modified with an organic onium ion are disclosed in JP-A-4-33955, and an aprotic polar solvent (for example, N, (N-dimethylacetamide, N-methylpyrrolidone) are uniformly mixed, the mixed solution is cast to obtain a polyamic acid film, and the polyamic acid film obtained is subjected to a thermal cyclization reaction to homogenize clay minerals that have been organized. There is a disclosure to obtain a dispersed polyimide film.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the method for producing a polyimide molded article of Japanese Patent No. 035, when the organized clay is mixed with a polyamic acid solution of a basic solvent, the organized clay aggregates and the organized clay is not uniformly dispersed in the polyimide matrix. It was not possible to obtain the desired highly stable polyimide composite material.
This is because the organized clay is uniformly dispersed in the aprotic polar solvent but not uniformly dispersed in the basic solvent.

Further, in the precipitation method in which a mixed solution of polyamic acid and organized clay is prepared in an aprotic polar solvent in which the organized clay is uniformly dispersed, and powder is deposited from this mixed solution, an aprotic polar solvent is used. Since the solvent had a higher solubility of polyamic acid than the basic solvent, it was not possible to obtain fine powder suitable for molding polyimide. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composite material powder in which an organically modified clay mineral is uniformly dispersed in a polyimide molded body and is excellent in dimensional stability, and a method for producing the same. .

[0007]

DISCLOSURE OF THE INVENTION The present inventors have noticed that the organized clay is uniformly dispersed and the polyamic acid is dissolved in the aprotic polar solvent. Then, by spraying and drying the slurry of the aprotic polar solvent in which the organized clay is dispersed and the polyamic acid is dissolved,
The inventors have found that a fine powder in which the organized clay and the polyamic acid are uniformly dispersed can be formed and completed the present invention.

The polyimide composite material powder of the present invention is characterized by being composed of an organized micro clay mineral obtained by organizing a micro clay mineral and a polyimide covering the organic micro clay mineral. Further, the method for producing a polyimide composite material powder of the present invention is a slurry-like liquid mixture obtained by dissolving and dispersing an intermediate polymer of polyimide and an organized micro clay mineral obtained by organizing a micro clay mineral in an aprotic polar solvent. And a powdering step of spray-drying the slurry-like mixed liquid to form a fine powdery polyimide-clay mineral composite material in which the organically modified fine clay mineral is dispersed in a polyimide resin. To do.

Organized clay mineral refers to, for example, one obtained by treating an organic onium ion with a compound treated with a compound having an organic onium ion. The organic onium ion refers to an organic compound having an onium ion at one end of the main chain. Examples of the onium ion include ammonium ion, pyridinium ion, sulfonium ion and phosphonium ion. The main chain is composed of a linear or branched carbon chain, and a part of the main chain may include a cyclic structure. The other end of the main chain does not necessarily have to be hydrogen, and may be a hydroxyl group, amino group, carboxyl group, nitro group, sulfone group, or derivative thereof. In order to extend the layer spacing of the clay mineral and ensure its dispersion effect sufficiently, it is desirable that the main chain has 6 or more carbon atoms, and in order to maintain the affinity with the aprotic polar solvent, It is desirable that the main chain has 20 or less carbon atoms. Taking the above points together, the most preferable organic onium ions include alkylammonium ions such as laurylamine ion, myristylamine ion, palmitylamine ion, and stearylamine ion.

Organization of clay minerals with organic onium ions, that is, formation of organized clay, is carried out by replacing exchangeable inorganic ions of clay minerals with organic onium ions. The weight ratio of the organic onium ion to the clay mineral is not particularly limited, but it is desirable that at least the exchangeable inorganic ion is sufficiently replaced by the organic onium ion.

There is no particular limitation on the synthesis of the clay mineral containing an organic onium ion, and it can be synthesized by various methods. For example, it can be synthesized by mixing a clay mineral and an organic onium ion in a solvent of one or more of water, methanol, ethanol, propanol, ethylene glycol, 1,4-butanediol, glycerin and the like. it can. For example, when the clay mineral is montmorillonite, it is desirable to use one or more of water, methanol and ethanol.

The clay mineral used in the present invention is preferably a layered clay mineral. Examples of the layered clay mineral include smectite clay minerals such as montmorillonite, saponite, beidellite, and stevensite, vermiculite, halosite, swelling mica, and the like. The cation exchange capacity of the layered clay mineral is 50
Approximately 300 meq / 100 g, which has a large contact area with the polyimide to be reacted or the raw material monomer thereof is desirable. Cation exchange capacity is 300 meq / 1
If the amount is more than 00 g, the interlayer bond strength of the layered clay mineral is too strong and the interlayer positive expansion is difficult, so the dispersibility in the polyimide is poor, and if less than 50 meq / 100 g, the organic onium ion Since the amount of adsorption is insufficient, the affinity with polyimide is insufficient.

The particle size of the clay mineral is 0.1 to 100 μm,
It is preferably 1 to 20 μm. The clay mineral preferably has the above-mentioned particle size and is flaky. A powder with a particle size of more than 100 μm has a small surface area and is compressed /
A good compact cannot be obtained during sintering. On the other hand, a powder having a particle size of less than 0.1 μm is too fine and the operability during molding is deteriorated. Specifically, the fine clay mineral is preferably a layered clay mineral having 5 or less layers, and ideally, a single layer clay mineral in which the layered clay mineral is exfoliated into a single layer. Also, when the whole clay mineral is 100%,
Layered clay minerals having 5 or less layers account for 50% or more, more preferably 70% or more.

The polyimide intermediate polymer used in the present invention is obtained by the polycondensation reaction of a dianhydride with a diamine and an acid, such as polyamic acid. Polyimide is formed by subjecting this intermediate polymer to a ring-closing reaction. As the raw material monomer of this intermediate polymer, all acid anhydrides and diamines that are known polyimide raw materials can be used. For example, as the acid anhydride, pyromellitic dianhydride and biphenyltetracarboxylic dianhydride can be used. Benzophenone tetracarboxylic acid dianhydride and the like, and diamines include 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, P-phenylenediamine, m-phenylenediamine and the like.

The intermediate polyimide polymer may be homopolymerized to synthesize a homopolymer. Alternatively, a copolymer composed of several kinds of monomers may be synthesized. It is also possible to copolymerize a dicarboxylic acid, a diol, or a derivative thereof, and use it as an intermediate polymer of polyamideimide, polyesteramideimide, or polyesterimide.

The aprotic polar solvent serves as a dispersion medium for dispersing the layered clay mineral containing an organic onium ion and a solvent for dissolving the polyamic acid of the intermediate polymer. As this aprotic polar solvent, N, N
-Dimethylacetamide, N-methylpyrrolidone, N,
N-dimethylformamide, 1,3-dimethylimidazolinone, etc. can be used. The aprotic polar solvent dissolves the polyimide raw material monomer and the intermediate polymer and has an affinity with the organized clay mineral. For this reason, the intermediate polymer of polyimide and the organized clay mineral can be well dispersed and mixed with each other at the molecular level in the aprotic polar solvent.

The production method of the present invention comprises a mixing step of dissolving and dispersing an intermediate polymer of polyimide and an organized fine clay mineral in an aprotic polar solvent to form a slurry-like mixed solution, and spray-drying the mixed solution. And a powdering step of forming a fine powdery polyimide-clay mineral composite material. In this mixing step, the organically modified fine clay mineral is directly added to the polyamic acid solution of the intermediate polymer and dispersed by stirring, or the polyamic acid solution and the slurry liquid in which the organized fine clay mineral is previously dispersed are mixed. Is obtained by When using the layered clay mineral, it is desirable to previously grind it into a desired state by using a mixer, a mill, a disintegrator, etc. as an auxiliary means for sufficiently performing the dispersion.

The polyamic acid solution can be obtained by dissolving a diamine, which is a raw material monomer for polyamic acid, and an acid dianhydride in an aprotic polar solvent, and polycondensating in this solution. The powdering step adopts a spray dry method, sprays the mixed liquid into fine droplets, and evaporates the liquid in this state. Thereby, the polyimide composite material powder of the present invention is obtained. Organized clay minerals are stably dispersed uniformly in the mixed solution at the minimum unit (molecular level), so spray drying this mixed solution removes only the solvent, and the clay mineral is a polyamide that maintains the molecular level dispersed state. It can be isolated as a fine powder of acid.

The powder may be pulverized and then heated to proceed the ring-closing polymerization of the polyamic acid of the intermediate polymer. The ring-closing polymerization is carried out in a non-oxidizing atmosphere at 150 ° C to 400 ° C, 0.1 to 20 ° C.
It is made by heating for a time. The dispersion state of the clay mineral does not change due to the ring closure reaction of the polyamic acid.
Moreover, the low crystallinity can be maintained without crystallization of the polyimide.

The polyimide composite material powder of the present invention is composed of an organized micro clay mineral and a polyimide covering the organized micro clay mineral. One powder of this polyimide composite material powder may contain a plurality of particle fine clay mineral particles. In such a case, it is preferable that the clay mineral particles are separately dispersed in the polyimide. Dispersion of the organized clay mineral in the polyimide means that the individual clay mineral particles are individually dispersed without coagulating with each other. If the clay mineral is a layered clay mineral, one by one,
Alternatively, it means a state in which multi-layered products having an average overlap of 5 layers or less are randomly mixed. Practically, it is preferable that 50% or more, preferably 70% or more of the individual particles are dispersed without being aggregated to form a lump.

The polyimide composite material powder is a fine powder suitable for compression / sinter molding and has a powder particle size of 0.1 to 100 μm.
It is preferably 1 to 20 μm. Powder particle size is 100μm
If it exceeds, the surface area becomes small and a good molded product cannot be obtained in compression / sinter molding. On the other hand, 0.1 μm
A powder having a particle size of less than is not preferable because handling at the time of molding is reduced because the powder is too fine.

In the polyimide composite material powder, the weight ratio of the organized clay mineral is 50 to 99.99 parts by weight of polyimide and 0.01 to 50 parts by weight of the organized clay mineral, based on 100% by weight as a whole. is there. 50 polyimide
When the amount is less than 50 parts by weight and the amount of the organized clay mineral is 50 parts by weight or more, the amount of the layered clay mineral in the obtained composite material is large, and the excellent mechanical properties and surface smoothness of the polyimide are impaired, which is preferable. Absent. When the amount of the organized clay mineral is less than 0.01 part by weight, the amount of the clay mineral containing the organic onium ion is too small, so that the effect on the polyimide matrix is small and the modification cannot be achieved.

Since this polyimide composite material powder is formed by spray drying, the resin retains a low crystallinity even when heated in the ring-closing reaction, and is excellent in moldability. This is X
This can be confirmed by the fact that no remarkable peaks of the polyimide crystal are observed in the range of 2θ = 10-35 ° in the line diffraction. The polyimide composite material powder of the present invention, polyimide, polyetherketone if necessary, in addition to clay minerals,
Further desired physical properties and characteristics can be adjusted by appropriately mixing a resin other than polyimide in addition to polysulfone, polyamide-imide and the like. Also, depending on the purpose, pigments and dyes, glass fibers, metal fibers, metal flakes,
Reinforcing materials and fillers such as carbon fibers, heat stabilizers, antioxidants, UV inhibitors, light stabilizers, lubricants, plasticizers, antistatic agents, flame retardants and the like can be added.

[0024]

In the polyimide composite material powder of the present invention, the organized clay mineral is dispersed in the polyimide matrix while maintaining the dispersed state at the molecular level. Therefore, in this polyimide composite material powder, a clay mineral is uniformly dispersed by compression / sintering molding or the like, and a polyimide resin molded product having good dimensional stability can be obtained. For example,
When compression / sinter molding is performed, the linear expansion coefficient in the direction perpendicular to the compression molding direction can be reduced by 70% or more at the maximum, and dimensional stability can be improved.

As the clay mineral, a layered clay mineral can be used, and since the number of layers can be made as small as 5 layers or less, it is possible to obtain a composite material powder which can be more uniformly dispersed and the clay mineral addition effect is further enhanced. The method for producing the polyimide composite material powder of the present invention is spray-drying a mixed solution of an aprotic polar solvent in the form of a slurry in which an intermediate polymer of polyimide is dissolved and an organized clay mineral is uniformly dispersed. While maintaining the dispersed state of the organized clay mineral formed in step 2, the solvent is rapidly removed from the fine droplets to form a fine powder. Therefore, the powder of the generated polyimide composite material becomes a polyimide-clay mineral composite material in which clay minerals are uniformly dispersed and can be used for the above molding.

This polyimide-clay mineral composite material can be molded alone or as a mixture with other compositions. Other compositions include polyimide resins, synthetic resins such as polyamide resins, inorganic fillers such as clay mineral powder, glass fibers,
Reinforcing materials such as whiskers can be mentioned.

[0027]

The present invention will be specifically described below with reference to examples. (Example 1) Diaminodiphenyl ether 120.14
g (0.6 mol) of N, N-dimethylacetamide (D
MAc) dissolved in 1153 g. Next, 130.22 g (0.597 mol) of pyromellitic anhydride was added, and the mixture was stirred at room temperature for about 1 hour. The polymerization reaction proceeds while generating heat,
A 12 wt% DMAc solution of polyamic acid, which is an intermediate polymer of polyimide, was obtained.

100 g of Na-montmorillonite (Kunipia F manufactured by Kunimine Industries Co., Ltd.) was dispersed in 3 liters of water, to which 44.1 g of laurylamine and 24.1 g of concentrated hydrochloric acid were added, and the mixture was stirred at room temperature for 60 minutes. did. After washing with water
Suction filtration was performed using a Buchner funnel to obtain a water-containing composite. This hydrous composite was freeze-dried to synthesize an organic clay mineral of montmorillonite containing lauryl ammonium ion.

30.03 g of Na-montmorillonite organically prepared with lauryl ammonium ion prepared above
(The amount of montmorillonite excluding the organic component was 21.77 g) was added to 683 g of DMAc, and the mixture was vigorously stirred for 1 hour with a homogenizer (finally, the clay content in the resin powder was 8% by weight).
The montmorillonite dispersion was prepared by adjusting the dispersion so that

The organically modified montmorillonite dispersion was added to the DMAc solution of the polyamic acid obtained above and vigorously stirred at a rotation speed of 800 rpm for 2 hours to prepare a uniform mixed slurry. 1.5 against 1 of this mixed slurry stock solution
DMAc was added at a ratio of 2 to dilute, and the viscosity of the mixed slurry solution was adjusted to 100 c. It was adjusted to about p (centipoise).

The diluted slurry was pulverized by a spray drying method. The spraying conditions at this time are as follows. Spraying device: Spray drying device for organic solvent (DA2SW-16N manufactured by Sakamoto Giken), Spraying system: Two-fluid nozzle system,
Hot air temperature: 170 ° C, air and nozzle pressure: 4 kg /
cm ² , atmosphere: under dry nitrogen (oxygen concentration 0.8%) The particle size of the organic clay mineral-containing polyamic acid powder obtained under the above conditions was 1 to 20 μm as a result of optical microscope observation. Moreover, when the content of the clay mineral (montmorillonite) in the powder was quantified by the cauterization method, it was found that the clay mineral was contained according to the charged amount.

Cauterization method: 0.1 g of clay-containing polyimide acid powder was put into a crucible, and all organic substances were incinerated by a method of heating with a gas burner for 3 hours, leaving only the clay minerals to reduce the amount of inorganic substances in the polyimide acid powder. It was quantified. 160 of this powder
The polyamic acid powder was converted to a polyimide powder by a ring-closing reaction by drying in a vacuum at 15 ° C. for 15 hours.

When the X-ray diffraction measurement of the produced clay-containing polyimide powder was carried out, no remarkable diffraction peak was observed in the angle region of 2θ = 10-35 °, and a polyimide powder of low crystallinity was obtained. I understood. Next, 10 g of this powder was compression / sinter-molded using a resistance heating type vacuum pressure hot press (FVPHP-R-10 manufactured by Fuji Denpa Kogyo KK).

10 g of the powder sample was placed in a cylindrical mold having a diameter of 40 mm, and vacuum was applied at room temperature for 5 minutes. Gradually pressurize to 200 atm and then 400 at 10 ° C / min
The temperature was raised to ° C. After maintaining in this state for 2 hours, the pressure was removed and the mixture was naturally cooled. The molded piece was taken out after the mold temperature reached 100 ° C or lower. Observation of this molded piece with a transmission electron microscope (TEM) revealed that 1
~ It was confirmed that they were uniformly dispersed in units of several layers.

In order to measure the linear expansion coefficient of the molded body, a test piece measuring 5 mm in length × 5 mm in width × 15 mm in thickness was cut out from the above-mentioned molded piece. The thickness direction of the test piece was made to coincide with the direction perpendicular to the compression molding direction. The measurement conditions of the linear expansion coefficient are as follows. Measuring device: Thermal stress strain measuring device (DT-3 manufactured by Shimadzu Corporation
0) Temperature range: room temperature to 300 ° C, heating rate: 2 ° C / mi
n, load: 500 mg The measured value of the linear expansion coefficient is 100 ° C .: 41 μm / m / ° C.
(1.0), 150 ° C .: 42 μm / m / ° C. (0.9
5), 200 ° C .: 44 μm / m / ° C. (0.92), 2
The temperature was 50 ° C .: 50 μm / m / ° C. (0.98). The values in parentheses are relative values based on the measured linear expansion coefficient of the clay-free polyimide shown in Comparative Examples.
That is, 0.92 indicates that the linear expansion coefficient is reduced by 8%.

Example 2 A procedure for preparing a hybrid (preparation of slurry) except that the addition amount of the organized clay mineral in Example 1 was 47.54 g (the amount of montmorillonite excluding the organic component was 34.14 g). , Spray dry,
All the compression / sintering moldings were carried out by the same method (at this time, the clay content was 12% by weight). The obtained organically modified clay mineral-containing polyimide powder was a fine and low-crystallinity powder having a particle size of 1 to 20 μm and contained the clay mineral in an amount as charged. Further, from the TEM observation of the molded piece, it was confirmed that the clay mineral was uniformly dispersed in the polyimide at the molecular level. The linear expansion coefficient was measured in the same manner as in Example 1, and as a result, 100 ° C .: 37 μm / m / ° C. (0.90), 15
0 ° C: 41 μm / m / ° C (0.92), 200 ° C: 4
6 μm / m / ° C. (0.96), 250 ° C .: 47 μm /
It was m / ° C (0.92), indicating that the linear expansion coefficient was reduced.

Example 3 Na-tetrasilicic mica (swelling mica ME10 manufactured by Cope Chemical Co., Ltd.) organized by octyl ammonium ion in the same manner as in Example 1 was used.
0T2) (hereinafter 8CH3-Mic) with an addition amount of 26.6.
The procedure of hybrid preparation (slurry adjustment, spray drying, compression / sinter molding) was all performed in the same manner except that the amount was 5 g (21.77 g of mica excluding organic matter). The content is 8% by weight). The obtained clay-containing polyimide powder is 1 to 20 μm.
It was a fine, low-crystallinity powder of m and contained as much clay as it was charged. In addition, TEM observation of the molded piece confirmed that clay was uniformly dispersed in the polyimide at the molecular level. The linear expansion coefficient was measured in the same manner as in Example 1, and as a result, 100 ° C .: 35 μm / m / ° C. (0.85),
150 ° C .: 39 μm / m / ° C. (0.89), 200
℃: 39μm / m / ℃ (0.81), 250 ℃: 44
μm / m / ° C. (0.86), indicating that the linear expansion coefficient was reduced.

(Comparative Example) Diaminodiphenyl ether 1
Dissolving 20.14 g in DMAc 1836 g,
And the procedure for preparing the hybrid of Example 1 was carried out in the same manner except that the step of mixing the organic clay and the step of mixing the organic clay were not included to obtain a polyimide powder. This powder was a fine and low crystallinity powder having a size of 1 to 20 μm. As a result of measuring the coefficient of linear expansion, 1
00 ° C: 41 μm / m / ° C, 150 ° C: 44 μm / m /
℃, 200 ℃: 48μm / m / ℃, 250 ℃: 51μm
/ M / ° C.

Therefore, the examples show that the linear expansion coefficient is lower than that of the comparative examples, and the molded products are excellent in dimensional stability.

 ─────────────────────────────────────────────────── ─── Continued Front Page (71) Applicant 390023674 Ei DuPont Do Nemours & Company E. I. DU PONT DE NEMO URS AND COMPANY 1007 Market Street, Wilmington, Delaware, USA 1007 (71) Applicant 393025921 DuPont Co., Ltd. 1-8-1, Shimo-Meguro, Meguro-ku, Tokyo Mitsuru Nakano Aichi, Aichi Prefecture 1 of 41 Yokomichi, Nagakute-cho, Nagakute-cho, Gunma Toyota Central Research Institute Co., Ltd.

Claims (9)

[Claims] 1. A polyimide composite material powder comprising an organized microclay mineral obtained by organizing a microclay mineral and a polyimide covering the organized microclay mineral. 2. The organically modified fine clay mineral is composed of an organically modified layered clay mineral, and the total amount of the layered clay mineral is 100%.
At least 50% is 5 layers or less.
The polyimide composite material powder according to item 1. 3. The polyimide composite material powder according to claim 1, wherein at least 50% of the layered clay mineral is a single layer based on 100% of the entire layered clay mineral. 4. A polyimide intermediate polymer composite comprising an organized micro clay mineral obtained by organizing a micro clay mineral and a polyimide intermediate polymer before the ring closure reaction covering the organic micro clay mineral. Material powder. 5. A mixing step of dissolving and dispersing an intermediate polymer of polyimide and an organized fine clay mineral obtained by organizing a fine clay mineral in an aprotic polar solvent to obtain a slurry mixture, and the slurry mixture. A method for producing a polyimide composite material powder, which comprises a step of spray-drying a liquid to form a fine powdery polyimide-clay mineral composite material in which the organically converted fine clay mineral is dispersed in a polyimide resin. 6. The method for producing a polyimide composite material powder according to claim 5, further comprising a ring-closing polymerization step of heating at least a part of the intermediate polymer of the polyimide by ring-closing polymerization after the powderizing step. 7. The polyimide composite according to claim 5, wherein the aprotic polar solvent comprises at least one of N, N-dimethylacetamide, N-methylpyrrolidone, N, N-dimethylformamide and 1,3-dimethylimidazolinone. Method of manufacturing material powder. 8. A molded body of a polyimide composite material, which is formed by molding the polyimide composite material powder according to any one of claims 1 to 3 or a mixture thereof with another composition. 9. A method for producing a polyimide composite material molded body, comprising compressing / sintering the polyimide composite material powder according to claim 5 or 6.