JP3531719B2 - Manufacturing method of polyimide resin molding - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyimide resin molded article excellent in toughness, high heat resistance, low linear expansion coefficient and low water absorption while maintaining the properties of a known polyimide resin molded article. Regarding

[0002]

2. Description of the Related Art Conventionally, as a polyimide resin molding,
3,3 ′, 4,4′-biphenyltetracarboxylic acid-based polyimide powder molded body, pyromellitic acid-based polyimide powder molded body, or a molded body obtained by heating and pressing a laminate of these polyimide precursor sheets It has been known. In particular, a polyimide powder molded body composed of a 3,3 ′, 4,4′-biphenyltetracarboxylic acid component and a p-phenylenediamine component has high heat resistance, high rigidity, a low linear expansion coefficient, and a low water absorption rate. , Are used in areas where these properties are needed. Further, a polyimide powder molded body composed of a pyromellitic acid component and 4,4′-diaminodiphenyl ether has high toughness and good machinability and is widely used.

Regarding the above-mentioned 3,3 ', 4,4'-biphenyltetracarboxylic acid-based polyimide powder molded body, for example, Japanese Patent Application Laid-Open No. 57-200452 (Japanese Patent Publication No.
No. 48571), JP-A-57-200453, etc., 3,3 ′, in N-methyl-2-pyrrolidone.
An example of obtaining a heat-compression molded article of an aromatic polyimide powder having an imidization ratio of 95% or more obtained by polymerizing and imidizing a 4,4′-biphenyltetracarboxylic acid component and an aromatic diamine component is described. ing. Furthermore, a polyimide powder compact containing an inorganic powder such as fine particle graphite is described in JP-A-63-81160.
According to these documents, it is shown that the polyimide powder compact has excellent mechanical strength.

However, a polyimide resin molded body having high strength and high heat resistance has a small elongation, and it may be chipped during molding such as when the molded body is secondarily processed into various shapes by cutting or the like, resulting in a complicated shape. It has been pointed out that it is difficult to form into a compact, that is, its toughness and machinability are low. Further, it is known that a pyromellitic acid-based polyimide powder molded body has a large linear expansion coefficient and water absorption, and a low flexural modulus and plasma resistance. That is, as a conventionally known polyimide resin molded body, 3,3 ', 4,4'
-Pyromellitic acid-based polyimide powder molding while maintaining high rigidity, high heat resistance, low linear expansion coefficient, low water absorption coefficient, plasma resistance and high strength characteristics of the biphenyltetracarboxylic acid component-based polyimide resin molding Has heat resistance,
None of them had high toughness and good machinability.

For this reason, attempts have been made to improve the fusion property between powders during heat compression molding in order to increase the elongation and mechanical strength of the molded body. For example, 3,3 ',
A method of compression molding a polyimide powder obtained by mixing a polyimide obtained from a 4,4′-biphenyltetracarboxylic acid component and an aromatic diamine component with a thermoplastic polyimide has been tried, but both components having completely different properties have been tried. It has been pointed out that uniform mixing is difficult, the mechanical strength and elongation of the obtained molded product do not reach a satisfactory level, and the heat resistance is rather lowered. Further, attempts have been made to obtain a molded product by once taking out the polyamic acid powder (aggregate), heating, drying and pulverizing it to obtain a polyimide powder, and compressing and molding this. However, it has been pointed out that it is not practical because it is difficult to control the temperature of the polyamic acid powder agglomerate during heating, and metal impurities are easily mixed in the polyamic acid powder.

[0006]

The object of the present invention is to maintain the characteristics of a known polyimide resin molding,
It is an object of the present invention to provide a polyimide resin molded product excellent in toughness, high heat resistance, low linear expansion coefficient and low water absorption.

That is, according to the present invention, the ratio of the aromatic tetracarboxylic acid component constituting the polyimide resin is 3,3.
', 4,4'-biphenyltetracarboxylic acid component is 85-
97 mol%, 2,3,3,4′-biphenyltetracarboxylic acid component is 15-3 mol%, aromatic diamine component is p-phenylenediamine, and dried at 200 ° C. or lower after completion of imidization reaction. An aroma having a two-layer structure obtained by covering a solid content mainly composed of highly heat-resistant crystalline polyimide, which is not observed in the temperature range of room temperature to 400 ° C., obtained by the above, with a coating layer composed of amorphous polyimide. Fill the mold with Group I polyimide powder, and 1) 100-
Preheat at 150 ℃, 400 ℃ or more, 1000kg /
After heat compression molding at a pressure of cm ² or more, or 2)
After pressure-molding at a temperature of 200 ° C. or lower, the pressure-molded body is free-sintered for 1 hour or more in a heating oven at a temperature of 400 ° C. or higher to mold, and the flexural modulus (23 ° C.) is 5 GPa. As described above, the present invention relates to a method for producing a polyimide resin molded product having a heat distortion temperature of 400 ° C. or higher, a linear expansion coefficient (50-200 ° C.) of 20-50 ppm / ° C., and a water absorption rate of 0.001-0.1%.

[0008]

Preferred embodiments of the present invention will be listed below. 1) Oxygen plasma resistance measured by etching rate is 8μ
The above-mentioned polyimide resin molded product having a plasma resistance of g / cm 2 · h or less. 2) The polyimide resin contains 3,3 ′, 4,4′-biphenyltetracarboxylic acid as an aromatic tetracarboxylic acid component, its acid ester or its acid dianhydride, and 2,
The above polyimide resin molding obtained by polymerizing and imidizing a mixture of 3,3 ′, 4′-biphenyltetracarboxylic acid, its acid ester or its acid dianhydride, and p-phenylenediamine as an aromatic diamine component. body.

3) The proportion of the aromatic tetracarboxylic acid component constituting the polyimide resin is 85-97 mol% of the 3,3 ', 4,4'-biphenyltetracarboxylic acid component,
The polyimide resin molded body as described above, wherein the 2,3,3 ′, 4′-biphenyltetracarboxylic acid component is 15-3 mol%. 4) The above-mentioned polyimide resin molded body, which is formed by heating and compressing a polyimide resin in a mold at a temperature of 400 ° C. or higher and a pressure of 1000 kg / cm 2 or higher. 5) The above-mentioned polyimide resin molded body, which is molded by cooling at a cooling rate of 0.5-2 ° C / min. 6) The molded body is one in which a polyimide resin is pressure-molded in a mold at a temperature of 200 ° C. or lower, and the pressure-molded body is subjected to free sintering in a heating oven at a temperature of 400 ° C. or higher for 1 hour or more. The above polyimide resin molded body. 7) The above-mentioned polyimide resin molded body, which is molded by cooling at a cooling rate of 0.5-2 ° C / min. 8) The above-mentioned polyimide resin molding, wherein the molding is pressure-molded at room temperature in a polyimide resin mold and the pressure-molded body is subjected to free sintering in a heating oven. 9) The above-mentioned polyimide resin molded product, wherein the molded product contains an inorganic or organic powder for improving slidability, workability, heat resistance, and / or abrasion resistance.

10) The above-mentioned polyimide resin molded body, which is for a grindstone filled with diamond fine particles and optionally other inorganic powder. 11) The above-mentioned polyimide resin molded body for a collet chuck, which is required to have machinability, heat resistance, vacuum characteristics and toughness. 12) The above-mentioned polyimide resin molded body, which is a semiconductor clamp ring in which the molded body is required to have plasma resistance, vacuum characteristics, rigidity, machinability and heat resistance. 13) The above-mentioned polyimide resin molded product, which is for a bearing retainer that requires heat resistance, oil resistance, sliding properties, machinability and rigidity.

The polyimide resin molded product of the present invention is preferably composed of a highly heat-resistant crystalline aromatic polyimide whose glass transition temperature (Tg) is not observed in the temperature range of room temperature to 400 ° C. Covered with a polyimide coating layer, logarithmic viscosity (30 ° C, 0.5 g / 1
(00 ml concentrated sulfuric acid) is about 0.5-2.0, and aromatic polyimide powder whose crystallinity is confirmed by a wide-angle X-ray diffraction method can be produced by heat compression molding in a mold.

As the above-mentioned aromatic polyimide powder, a solid content mainly composed of a highly heat-resistant crystalline aromatic polyimide, which has a glass transition temperature (Tg) not observed in the temperature range of room temperature to 400 ° C., preferably 3, A polyimide solid content (particles) derived from a 3 ′, 4,4′-biphenyltetracarboxylic acid component and paraphenylenediamine is covered with a coating layer made of an amorphous polyimide, and a logarithmic viscosity (30
(° C, 0.5 g / 100 ml concentrated sulfuric acid) within the above range, and having a crystallinity of about 20% or more by a wide-angle X-ray diffraction method. A polyimide powder having a two-layer structure covered with a coating layer made of a polymer, that is, the inner layer portion of the particle is an aromatic polyimide having crystallinity, while the outer layer thereof is a thin layer of amorphous polyimide. An example is a structured polyimide powder.

It is preferable that the above-mentioned non-crystalline polyimide coating covers almost the entire surface of the crystalline aromatic polyimide particles. According to the above polyimide powder, the polymer on the surface of the powder particles is sufficiently melted at the time of molding, and since they are fused and bonded to each other, a molded article having a highly balanced heat resistance, mechanical strength and elongation is obtained. It is thought to be obtained.

The above-mentioned aromatic polyimide powder is preferably prepared by the following method, that is, an aromatic tetracarboxylic acid component which gives a crystalline aromatic polyimide, for example, 3,3 ',
4,4'-biphenyltetracarboxylic acid or its acid dianhydride or its esterification product with an acid and lower alcohol, and a tetracarboxylic acid component giving an amorphous polyimide, for example, preferably 2,3,3 ' , 4'-Biphenyltetracarboxylic acid or tetracarboxylic acid containing an acid dianhydride or an ester of the acid and a lower alcohol (both are preferably acid dianhydrides) as a main component to give an amorphous polyimide Acid component (preferably 2, 3, 3 ',
4′-biphenyltetracarboxylic acids) and p-phenylenediamine may be adversely affected in some cases, with an aromatic tetracarboxylic acid component containing about 3 mol% or more and 15 mol% or less of all tetracarboxylic acid components. In another range, the other aromatic tetracarboxylic dianhydride and the other aromatic diamine are polymerized and imidized in an organic polar solvent by a known method in an approximately equimolar amount, and then powder is recovered from the reaction system. Manufactured. The aromatic polyimide powder preferably has a high molecular weight and an average particle size (primary particles) of about 1 to 20 μm.

According to the above-mentioned method, while the fine particles of the crystalline aromatic polyimide are produced, they are made to have a high molecular weight and imidized, and then the amorphous polyimide is made insoluble to precipitate the polyimide powder, and then the powder is recovered. A polyimide powder can be obtained. According to this method, it is a polyimide powder having a two-layer structure, the residual reaction solvent is small, and uniform particle formation can be easily performed. In this case, when the proportion of the non-crystalline polyimide increases, a large amount of aggregates of polyimide particles are aggregated, which causes deterioration of the physical properties of the obtained molded body.

The other aromatic tetracarboxylic acids mentioned above include pyromellitic acid or its acid dianhydride, 3,
3 ', 4,4'-benzophenone tetracarboxylic acid or its acid dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) propane or its acid dianhydride, bis (3,4-dicarboxy) Phenyl) methane or its acid dianhydride, bis (3,4-dicarboxyphenyl) ether
Examples thereof include tellurium and its acid dianhydride.

Other aromatic diamines mentioned above include metaphenylenediamine, 4,4'-diaminodiphenylether, 4,4'-diaminodiphenylmethane, 4,
4'-diaminodiphenylpropane, bis (4-aminophenyl) dimethylsilane, 1,4-bis (4-amino-phenoxy) benzene, 1,3-bis (4-amino-)
Examples thereof include phenoxy) benzene.

The above-mentioned aromatic polyimide powder is, for example,
In the presence of an inert gas, 15-100% by weight consists of an amide-based solvent and 85-0% by weight of a non-amide-based solvent having a boiling point of 180 ° C. or higher in a reaction solvent containing 0.5-5% by weight of water. Preferably, the proportion of all monomers in the solution is 2-25
The above-mentioned aromatic tetracarboxylic acid component and aromatic diamine component are added in approximately equimolar amounts so as to reach a weight percentage of 3 to 20% by weight, and the temperature is raised while distilling the produced water.
The fine particles are precipitated at a temperature in the range of 1800C to less than 180C, and the reaction is conducted at a temperature in the range of 160-250C for 0.5-
Continuously for 20 hours, logarithmic viscosity (30 ° C., 0.5 g / 10
0 ml concentrated sulfuric acid) is 0.2-1.5, and the imidation ratio is 95% or more. The above non-amide solvent and water may be used as a mixed solvent prior to the polyamic acid synthesis, or may be added to the reaction solution after the polyamic acid synthesis.

Prior to the step of depositing the fine particles, 1
After adjusting the temperature of the reaction solution to at least 00 ° C and less than 180 ° C, an imidization catalyst, preferably an imidazole-based imidization catalyst, is added to the reaction system and imidization is performed under the heating conditions described above to control the imidization rate. By doing so, the particle size and particle size distribution of the produced polyimide powder can be adjusted.

As the amide-based solvent, N-methyl-2-pyrrolidone, N, N-dimethylacetamide,
Examples thereof include N, N-dimethylformamide and N-methylcaprolactam, and N-methyl-2-pyrrolidone is particularly preferably used.

There is no particular limitation on the method for obtaining the polyimide powder after the completion of the above-mentioned imidization reaction. For example, the reaction mixture is cooled as it is or after being cooled to room temperature, the aromatic polyimide powder is filtered off, and the powder is used as a solvent. Wash with
A method of drying can be adopted. As the solvent for washing, any solvent having a low boiling point that can replace the reaction solvent may be used, and water or alcohols such as methanol and ethanol is preferable. Further, the drying is carried out under normal pressure or reduced pressure of 250 ° C. or lower, preferably 200 ° C. or lower, preferably 350 ° C. for 1 hour, and the weight loss rate is 1%.
Hereinafter, it is particularly preferable that the dried state is 0.5% or less. The aromatic polyimide powder does not have to be pulverized, but may be pulverized with a Henschel mixer, a wheel mill or the like. Further, for the purpose of separating and removing a very small amount of agglomerates generated during polymerization, it is preferable to separate the agglomerates by a vibrating screen in order to improve the physical properties of the molded product.

The polyimide resin molded product of the present invention can be preferably manufactured by filling the above-mentioned aromatic polyimide powder in a mold and applying heat and pressure simultaneously or separately to heat compression molding. The aromatic polyimide powder is filled in a mold and preheated at 100 to 150 ° C. for about 5 to 60 minutes to remove water adhering to the polyimide resin, and then at a molding temperature of 430 to 470 ° C. and a molding pressure of 100.
It can be suitably manufactured by compression molding at 0 to 10000 Kg / cm 2 for about 5 to 30 minutes. These temperatures and pressures may be arbitrarily selected within the above range. 0.5-2 in the mold of the heat-compression molded product
Cooling at a cooling rate of ° C / min is preferable for improving the physical properties of the molded product. Furthermore, the compression molded molded body is
You may post-sinter at 400-460 degreeC. It is preferable to cool the sintered compact at a cooling rate of 0.5-2 ° C./minute in order to improve the physical properties of the compact and prevent cracking of the compact.

Further, during the production of the above powder compact, artificial diamond, silica, mica, kaolin, boron nitride, aluminum oxide, iron oxide, graphite,
Inorganic filler such as molybdenum sulfide or iron sulfide, or
Various fillers such as organic fillers such as fluororesin may be mixed with the above-mentioned polyimide powder (which may be compounded by any method of internal addition and external addition) and used.

In the above heat compression molding, as an apparatus for producing a polyimide powder compact, for example, a four-column type hydraulic press, a high pressure hot press, a WIP apparatus and the like can be mentioned. Further, the preformed body, for example,
It is preferably formed by a method using Wet-CIP, Dry-CIP, a high pressure press, a hydraulic press, a rotary press, or a tablet machine. Further, the polyimide resin molded product of the present invention can be manufactured by applying the above-mentioned heat compression molding method to a sheet-shaped laminate.

The polyimide resin molding obtained by the above heat compression molding is a conventionally known 3,3 ', 4,4'-
High elongation, low water absorption, and low linear expansion can be realized without lowering the excellent heat resistance, dimensional stability, etc. of the polyimide powder molded body obtained from biphenyltetracarboxylic acids and paraphenylenediamine.

The polyimide resin molding of the present invention contains an inorganic or organic powder, and has slidability, workability,
The molded product can be used for applications requiring heat resistance and / or abrasion resistance. Further, the polyimide resin molded body of the present invention can be used as a molded body for a grindstone filled with diamond fine particles and optionally other inorganic powder. Further, the polyimide resin molded body of the present invention can be used as a molded body for a collet chuck which requires cutting workability, heat resistance, vacuum characteristics and toughness.
Furthermore, the polyimide resin molded body of the present invention can be used as a molded body for a semiconductor clamp ring which is required to have plasma resistance, vacuum characteristics, rigidity, machinability and heat resistance. Further, the polyimide resin molded body of the present invention can be used as a bearing retainer molded body which is required to have heat resistance, oil resistance, sliding characteristics, machinability and rigidity.

[0027]

EXAMPLES Examples of the present invention will be shown below. In each of the following examples, various physical properties of polyimide powder compacts were measured by the following test methods. Tensile properties: Measured according to ASTM D-638. Bending property: Measured according to ASTM D-790. Linear expansion coefficient: Measured according to ASTM D-696. Heat distortion temperature: Measured in accordance with ASTM D-648. Water absorption rate: Based on ASTM D-570, the water absorption rate was measured by allowing the molded body to stand in water at 23 ° C for 24 hours. Plasma resistance characteristics: Using a plasma generator manufactured by Mori Engineering Co., Ltd., in a RIE mode, the molded body is irradiated with plasma under the conditions of an output of 700 W, a pressure of 65 Pa, and a temperature of 145 ° C., and the etching rate of the molded body is changed. It was measured over time. Vacuum characteristics: The ultimate vacuum degree at 100 ° C. was measured using a high precision temperature programmed desorption gas analyzer EMD-WA1000 manufactured by Electronic Science Co., Ltd.

Example 1 Drying 3,3 ', 4,4'-biphenyltetracarboxylic acid diacid while passing nitrogen gas through a four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube and a moisture meter. Charge 408.03 g of anhydride, 30.71 g of 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride and 2930 g of N-methyl-2-pyrrolidone, raise the temperature to 50 ° C. with stirring, and completely. Dissolved into a uniform solution. To this was added p-phenylenediamine (161.26 g),
Hold for 0.5 hour. Then, the temperature was raised to 190 ° C. in 1.5 hours, and the reaction was carried out at this temperature for 3 hours. Precipitation of polyimide resin particles was observed at 161 ° C on the way. Further, water distilled during the reaction was promptly removed from the system. N-methyl-2
-The yellow polyimide resin particles dispersed in the pyrrolidone solution were collected by filtration, and further washed with boiling water three times (98 N-methyl-2-pyrrolidone, 1 hour),
After drying with hot air at 130 ° C under normal pressure, the pressure is reduced to 200
N-methyl-which is present in a small amount in the polyimide resin particles at ℃
2-Pyrrolidone was dried and removed to obtain polyimide resin particles.

The obtained polyimide resin particles have a two-layer structure in which the entire surface of the crystalline polyimide particles is covered with a coating layer made of amorphous polyimide, as observed by a transmission electron microscope (showing a cross-sectional view). The polymer has an inherent viscosity (30 ° C., 0.5 g / 100 ml concentrated sulfuric acid)
Was about 0.6, the average particle size (primary particle) was 6 μm, and the crystallinity was 38% by analysis by the wide-angle X-ray diffraction method (Louland method). The glass transition temperature is 400 ℃
Was not observed, the loss on heating from room temperature to 350 ° C. was 0.7%, and the average particle size was 7.5 μm.

The obtained polyimide resin particles are filled in a mold and pre-heated at 130 ° C. for about 5 hours to pre-form, then molding temperature 450 ° C., molding pressure about 3000 Kg / cm.
It was compression-molded at 2 for about 5 minutes, heated and compression-molded, and program-cooled in a heating oven at a cooling rate of 1 ° C./minute to obtain a molded body. The obtained molded body was cut into a predetermined shape and the physical properties were evaluated. During the cutting process, the molded product was not chipped.

Tensile strength: 110 Mpa Tensile elongation: 4.0% Bending elastic modulus: 7.5 Gpa Linear expansion coefficient: 35 ppm / ° C Heat distortion temperature: 470 ° C Water absorption rate: 0.03% Oxygen-resistant plasma characteristics: 6.6 μm / cm2 · hr Vacuum characteristics: 1.5 × 10 −7 Torr · L / sec · cm
2 The above results show that the polyimide resin molded body obtained in Example 1 has high toughness and goodness while maintaining good high heat resistance, low linear expansion coefficient, low water absorption rate, plasma resistance and high vacuum characteristics. It shows that it has excellent machinability.

Comparative Example 1 As polyimide resin powder, commercially available 3,3 ', 4,4'
-Biphenyltetracarboxylic dianhydride-4,4'-diaminodiphenyl ether type polyimide resin powder (commercial item 1) was used to obtain a molded body. The evaluation results are shown below. Tensile strength: 116 Mpa Tensile elongation: 5.0% Bending elastic modulus: 4.2 Gpa Linear expansion coefficient: 55 ppm / ° C Thermal deformation temperature: 336 ° C Water absorption rate: 0.40% Oxygen-resistant plasma characteristics: 14.6 μm / cm 2 · hr Vacuum characteristics: 4.6 × 10 -5 Torr · L / sec · cm
2

Comparative Example 2 A molded product was obtained by using a commercially available pyromellitic dianhydride-4,4'-diaminodiphenyl ether type polyimide resin powder (commercially available product 2) as the polyimide resin powder. . The evaluation results are shown below. Tensile strength: 72 Mpa Tensile elongation: 7.5% Bending elastic modulus: 2.5 Gpa Linear expansion coefficient: 54 ppm / ° C Heat deformation temperature: 360 ° C Water absorption rate: 0.24% Oxygen-resistant plasma characteristics: 9.2 μm / cm ² · hr Vacuum characteristics: 1.8 × 10 ^-4 Torr · L / sec · cm
²

Example 2 Diamond fine particles at the time of polymerization in Example 1: No. 800
A polyimide resin powder containing diamond fine particles was obtained in the same manner except that 25% by volume of (20-30 μm) was added to the polyimide for polymerization. A molded body was obtained using this diamond-containing polyimide resin powder. The evaluation results are shown below. Tensile strength: 152 Mpa Tensile elongation: 2.5% Flexural modulus: 8.5 Gpa Linear expansion coefficient: 22 ppm / ° C Heat deformation temperature: 472 ° C Water absorption: 0.02%

Example 3 75% by volume of the polyimide resin powder obtained in Example 1 and 25% by volume of the diamond fine particles used in Example 2 were blended with a Henschel mixer, and this mixture was filled in a mold and 5000 kg at room temperature. Pressure molding at a pressure of / cm2,
Remove the molded polyimide molding from the mold and
Baking for 5 hours in a heating oven at 0 ° C. This fired body was evaluated in the same manner as in Example 1. The evaluation results are shown below. Tensile strength: 143Mpa Tensile elongation: 3.0% Flexural modulus: 5.2Gpa Linear expansion coefficient: 36ppm / ° C Heat distortion temperature: 471 ° C Water absorption: 0.02%

[0036]

Since the present invention has the structure described in detail above, it has the following effects. It is shown that the polyimide resin molded product of the present invention has both high toughness and good machinability while maintaining good high heat resistance, low linear expansion coefficient, and low water absorption.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI B29L 31:04 B29L 31:04 31:34 31:34 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 5 / 00-5/24 B29C 43/00-43/58 C08G 73/00-73/26

Claims (9)

(57) [Claims] 1. The ratio of the aromatic tetracarboxylic acid component constituting the polyimide resin is 85-97 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic acid component, and 2,3,3.
3,4'-biphenyltetracarboxylic acid component is 15-3
Mol%, the aromatic diamine component is p-phenylenediamine, and the glass transition temperature obtained by drying at 200 ° C. or lower after completion of the imidization reaction is high heat resistance which is not observed in the temperature range of room temperature to 400 ° C. Aromatic polyimide powder having a two-layer structure obtained by covering a solid content mainly composed of crystalline polyimide with a coating layer composed of amorphous polyimide is filled in a mold, and 1) preheated at 100 to 150 ° C.,
After heat compression molding at a pressure of 400 ° C or higher and 1000 kg / cm ² or higher, or 2) pressure molding at a temperature of 200 ° C or lower, the pressure molded body is placed in a heating oven at a temperature of 400 ° C or higher. Bending elastic modulus (23 ° C) of 5 GPa or more, thermal deformation temperature of 400 ° C or more, and linear expansion coefficient (50-200 ° C) of 2 for free sintering for 1 hour or more.
A method for producing a polyimide resin molded product, which has a water absorption of 0-50 ppm / ° C and a water absorption of 0.001-0.1%. 2. The method for producing a polyimide resin molded body according to claim 1, wherein the molded body has a plasma resistance of not more than 8 μg / cm ² · h as measured by etching rate. 3. A polyimide resin comprising 3,3 ′, 4,4′-biphenyltetracarboxylic acid as an aromatic tetracarboxylic acid component, its acid ester or its acid dianhydride and 2,3,3 ′, 4 ′. -Production of a polyimide resin molded article according to claim 1, wherein a mixture of biphenyltetracarboxylic acid, its acid ester or its acid dianhydride and p-phenylenediamine as an aromatic diamine component are polymerized and imidized. Law. 4. The method for producing a polyimide resin molded article according to claim 1, wherein the molded article is formed by cooling at a cooling rate of 0.5-2 ° C. 5. The polyimide resin molded article according to claim 1, wherein the molded article contains an inorganic or organic fine powder for improving slidability, workability, heat resistance, and / or abrasion resistance. Manufacturing method. 6. The method for producing a polyimide resin molded body according to claim 1, wherein the molded body is for a grindstone filled with diamond fine particles and optionally other inorganic powder. 7. The method for producing a polyimide resin molded article according to claim 1, wherein the molded article is for a collet chuck which is required to have machinability, heat resistance, vacuum characteristics and toughness. 8. The method for producing a polyimide resin molded body according to claim 1, wherein the molded body is a semiconductor clamp ring which is required to have plasma resistance, vacuum characteristics, rigidity, machinability and heat resistance. 9. The method for producing a polyimide resin molded article according to claim 1, wherein the molded article is for a bearing retainer which is required to have heat resistance, oil resistance, sliding characteristics, machinability and rigidity. .