JPH01138266A - Polyimide composite material - Google Patents

Abstract

PURPOSE:To obtain a polyimide composite material freed of voids in the interface between a polyimide and a fibrous reinforcement, by mixing a specified polyimide with a fibrous reinforcement. CONSTITUTION:This polyimide composite material is formed of a fibrous reinforcement and a polyimide having a basic skeleton composed of repeating units of formula I (wherein X is a direct bond, a 1-10C bivalent hydrocarbon group, a carbonyl group or the like, Y1-Y4 are each a hydrogen atom, a lower alkyl group or a lower alkoxyl group, and R is a tetravalent group selected from among a 2C or higher aliphatic group, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, etc.) and formed by thermally or chemically imidating a polyamic acid obtained by reacting 1.0mol of a tetracarboxylic acid dianhydride of formula III (wherein X and Y1-Y4 are each as defined above) with 1.0-1.5mol of an ether diamine of formula III (wherein X and Y1-Y4 are as defined above) in the presence of 0.001-1.0mol of aliphatic and/or cycloaliphatic dicarboxylic acid dianhydride of formula IV (wherein Z is a 1-10C aliphatic and/or cycloaliphatic group).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyimide composite material that has excellent heat resistance, chemical resistance, mechanical strength, and moldability.

[Conventional technology]

Conventionally, molded products made from composite materials made of polyimide and fibrous reinforcing materials have excellent mechanical strength, especially strength retention at high temperatures, as well as excellent solvent resistance and dimensional stability, so they have been used in space. It is attracting attention as a structural material for aircraft, etc.

However, since polyimide generally has a high melt viscosity, composite materials using polyimide as a matrix require stricter molding conditions than composite materials using engineering plastics such as polycarbonate or polyethylene terephthalate as a matrix, which poses problems. was there.

Special polyimides with low melt viscosity and excellent processability are also known, but these resins have low heat distortion temperatures and are soluble in solvents such as halogenated hydrocarbons, so these resins can be used as a matrix. Composite materials have had problems with heat resistance and chemical resistance.

On the other hand, one of the inventors of the present invention first studied mechanical properties, thermal properties,
A polyimide having excellent electrical properties, solvent resistance, etc., and heat resistance is represented by the formula (I) (wherein, X is a direct bond, a divalent hydrocarbon group having 1 to 10 carbon atoms, hexafluorinated isopropylidene) Yl, Y2,
Y.

and Y4 each represent a group selected from the group consisting of hydrogen, a lower alkyl group, a lower alkoxy group, chlorine or bromine, and R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group. represents a tetravalent group selected from the group consisting of a group group, a fused polycyclic aromatic group, and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. ) We have discovered a polyimide having a repeating unit represented by
No. 62-86021, Japanese Patent Application No. 61-076475, No. 61-274206, etc.). The above-mentioned polyimide is a new heat-resistant resin having many good physical properties, and a composite material made of the polyimide and a fibrous reinforcing material has also been developed (Japanese Patent Application No. 61-901705).

However, since the above-mentioned polyimide has a high melt viscosity, when it is made into a composite material, voids are generated at the interface between the fibrous reinforcing material and the polyimide, and there is a problem that a material having sufficient mechanical strength cannot be obtained.

[Problem that the invention seeks to solve]

An object of the present invention is to obtain a polyimide composite material having excellent mechanical strength and having no voids at the interface between the polyimide and the fibrous reinforcing material without impairing the original properties of the polyimide.

[Means for solving problems]

The present inventors conducted intensive research to solve the above problems, and found that in a polyimide-based composite material consisting of polyimide and a fibrous reinforcing material, the polyimide is represented by the formula (I) (wherein X,
A tetracarboxylic dianhydride whose basic skeleton is a repeating unit (Y, ~Y,, R are the same as above), and the polyimide is represented by the formula (n) ]111 (wherein R is the same as above) 1.0 molar ratio, and ether diamine represented by formula (III) 1.0 to 1
．． (wherein X, Y+, Yz, Ys and Y4 are the same as before) aliphatic and/or cycloaliphatic dicarboxylic acid anhydride of formula (IV) from 0.001 to 1 Represents a divalent group consisting of thermally or chemically imidized polyamic acid obtained in the presence of a .0 molar ratio (hereinafter abbreviated as dicarboxylic acid anhydride) and/or a cycloaliphatic group) This is a polyimide-based composite material characterized by being a polyimide that can be used as a polyimide.

Ni(I) as a raw material for producing the polyimide of the present invention
As the ether diamine having I), bis[4-
(3-aminophenoxy)phenylcomethane, 1,1-
Bis(4-(3-7minophenoxy)phenyl]ethane, 2,2-bis(4-(3-aminophenoxy)phenyl)propane, 2-[4-(3-aminophenoxy)phenyl]2-C4-C3 -aminophenoxy)-3-
methylphenyl]propane, 2,2-bisC4-<3-
aminophenoxy)-3-methylphenyl]propane,
2- (4-(3-aminophenoxy)phenyl)-2
-(4-(3-aminophenoxy) -3,5-dimethylphenyl]propane, 2,2-bis[4-(3-aminophenoxy) -3,5-dimethylphenyl]propane, 2,2-bis( 4-(3-aminophenoxy)phenylcobutane, 2,2-bis[4-(3-aminophenoxy)phenyl)-1,1,1,3,3,3-hexafluoropropane, 4.4”- Bis(3-aminophenoxy)biphenyl, 4,4゛-bis(3-aminophenoxy)-3-methylbiphenyl, 4,4°-bis(3
-aminophenoxy)-3゜3°-dimethylbiphenyl, 4,4°-bis(3-aminophenoxy) -3,5
-dimethylbiphenyl, 4°4°-bis(3-aminophenoxy) -3,3',5.5°-tetramethylbiphenyl, 4.4'-bis(3-aminophenoxy) -
3,3'-dichlorobiphenyl, 4.4''-bis(3-
aminophenoxy)-3,5-dichlorobiphenyl,
4,4°-bis(3-aminophenoxy) -3,3°
, 5.5"-tetrachlorobiphenyl, 4.4"-bis(3-aminophenoxy) -3,3°-dibromobiphenyl, 4,4"-bis(3-aminophenoxy) -
3,5-dibromobiphenyl, 4,4'-bis(3-aminophenoxy) -3,3'',5.5''-tetrabromobiphenyl, bis(4-(3-aminophenoxy)
Phenylkoketone, bis(4-(3-aminophenoxy)phenyl)sulfide, bisC4-(3-aminophenoxy)-3-methoxyphenyl]sulfide, (4-
(3-aminophenoxy)phenyl)[:4-(3-aminophenoxy)3.5-dimethoxyphenyl fusulfide, bis(4-(3-aminophenoxy)-3,
5-dimethoxyphenyl fusulfide, bis(4-(3
-aminophenoxy)phenyl]sulfone, etc., and these may be used alone or in combination of two or more.

Note that, as long as the good physical properties of the polyimide used in the method of the present invention are not impaired, there is no problem in substituting a part of the above-mentioned diamine with a diamine used in other known polyimides.

Examples of the tetracarboxylic dianhydride represented by formula (ff) include ethylenetetracarboxylic dianhydride,
Butane tetracarboxylic dianhydride, cyclopenkune tetracarboxylic dianhydride, pyromellitic dianhydride, 1.
1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis( 3,4-dicarboxyphenyl)propanihydride, 2,2-bis(2,3-dicarboxyphenyl)propanihydride, 2,2-bis(3
,4-dicarboxyphenyl) -1,1,L3.3.
3-hexafluoropropanihydride, 2,2-bis(
2,3-dicarboxyphenyl) -1,1,1,3,
3,3-hexafluoropropanihydride, 3.3',
4.4'-Benzyphenonetetracarboxylic dianhydride, 2.2',3゜3゛-benzophenonetetracarboxylic dianhydride, 3,3°,4.4'-biphenyltetracarboxylic dianhydride Anhydride, 2,2°, 3.3'-biphenyltetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, bis (3,4-dicarboxyphenyl)sulfone dianhydride, 4.4"-(
p-phenylenedioxy) cyphthalic dianhydride, 4゜4
'-(m-phenylenedioxy)cyphthalic dianhydride,
2,3,6.7-naphthalenetetracarboxylic dianhydride, 1,4,5.8-naphthalenetetracarboxylic dianhydride, 1,2,5.6-naphthalenetetracarboxylic dianhydride, 1. 2,3.4-benzenetetracarboxylic dianhydride, 3,4,9.10-perylenetetracarboxylic dianhydride, 2.3,6.7-anthracenetetracarboxylic dianhydride, 1,2, 7,8-phenanthrenetetracarboxylic dianhydride, etc., and these tetracarboxylic dianhydrides may be used alone or in a mixture of two or more.

Examples of the dicarboxylic anhydride represented by formula (rV) include malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, pimelic anhydride, speric anhydride, azelaic anhydride, sebacic anhydride, Methylmalonic anhydride, ethylmalonic anhydride, dimethylmalonic anhydride, methylsuccinic anhydride, 2,2-dimethylsuccinic anhydride, 2,3-dimethylsuccinic anhydride, tetramethylsuccinic anhydride, maleic anhydride, citraconic anhydride , glutaconic anhydride, methylenesuccinic anhydride, allylmalonic anhydride, terraconic anhydride, muconic anhydride, cyclobutanedicarboxylic anhydride, cyclohexanedicarboxylic anhydride, cyclohexenedicarboxylic anhydride, silaunoic anhydride, etc., and these fatty acids The group and/or alicyclic dicarboxylic acid anhydrides may be used alone or in combination of two or more.

In the present invention, 1.0 to 1.5 molar ratio of ether diamine having formula (III) is used to 1.0 molar ratio of tetracarboxylic dianhydride having formula (I[), and 0 to 1.5 molar ratio of ether diamine having formula (III) is used. .001-1.0 molar ratio, preferably 0.01
It is obtained by thermally or chemically imidizing a polyamic acid obtained in the presence of a molar ratio of ~0.5, but the dicarboxylic anhydride used here is a feature of the present invention, and the dicarboxylic anhydride is a polyimide. A substance that directly or indirectly contributes to the reaction during the production of polyimide, serves as a part of the constituent components of polyimide, or acts as a catalyst for the polyimide production reaction, and plays a major role in obtaining polyimide with good processability. It is. That is, if the dicarboxylic acid anhydride is used in a molar ratio of less than 0.001, a polyimide with good processability cannot be obtained, and conversely, if it is used in a molar ratio of more than 1.0, a polyimide with good mechanical properties cannot be obtained.

Polyimide having good processability can be produced in the presence of dicarboxylic acid anhydride at a molar ratio of 0.001 to 1.0;
In this case, the ratio of tetracarboxylic dianhydride and ether diamine used as raw materials for polyimide is 1.0 molar ratio of tetracarboxylic dianhydride to 1.0 molar ratio of ether diamine.
It is effective when using a ratio of 0 to 1.5; outside this range, the polyimide of the present invention having good thermal stability at high temperatures cannot be obtained. Polyimides are produced using anhydrides, and in this case all known methods for producing polyimides can be used. That is, (I) tetracarboxylic dianhydride, ether diamine, and dicarboxylic anhydride are dissolved in an organic solvent (e.g., N,N-dimethylacetamide, N,
N-dimethylformamide (such as those commonly used for polyimides) to form an amic acid, which is then treated in the presence or absence of a chemical imidizing agent (e.g. triethylamine, acetic anhydride, etc.) to form a polyimide. Method,(
2) After dissolving the tetracarboxylic dianhydride and ether diamine in an organic solvent, adding the dicarboxylic anhydride,
After forming an amic acid, it is treated to form a polyimide in the presence or absence of a chemical imidizing agent; (3) an ether diamine and a dicarboxylic acid anhydride are dissolved in an organic solvent, and then a tetracarboxylic dianhydride is formed; (4) A method of adding a compound to form an amic acid and then processing it in the presence or absence of a chemical imidizing agent to form a polyimide.
This method involves mixing dicarboxylic acid anhydride and king powder in powder form, and then treating the mixture in the presence or absence of a chemical imidizing agent to form a polyimide. The temperature at which amic acid is usually made is 0°C.
~250°C is preferred, and the temperature at which the amic acid is thermally imidized is preferably 100'C ~ 400°C.

By any of the above methods, a polyimide having good fluidity at high temperatures, which is a feature of the present invention, can be obtained.

When the polyimide of the present invention is subjected to melt molding, other thermoplastic resins such as polyethylene, polypropylene, polycarbonate, polyarylate, polyamide, polysulfone, polyether sulfone, polyether ketone, and It is also possible to blend ether ether ketone, polyphenylene sulfide, polyamideimide, polyetherimide, modified polyphenylene oxide, etc. in appropriate amounts depending on the purpose. Furthermore, the following fillers used in ordinary resin compositions may be used to the extent that the purpose of the invention is not impaired. In other words, wear-resistance improving materials such as graphite, carbon random, silica powder, molybdenum disulfide, and fluorine resin, reinforcing materials such as glass fiber, carbon fiber, boron fiber, silicon carbide fiber, carbon whisker, asbestos, metal fiber, and ceramic fiber. , antimony dioxide, magnesium carbonate, calcium carbonate and other flame retardant improvers,
Electrical property improving materials such as clay and mica, asbestos,
Tracking resistance improvers such as silica and graphite, acid resistance improvers such as barium sulfate, silica, and calcium mekusilicate, thermal conductivity improvers such as iron powder, zinc powder, aluminum powder, and copper powder, and other glass beads and glass balls. , talc, diatomaceous earth, alumina, shirasu balloon, hydrated alumina, metal oxides, colorants, etc.

The fibrous reinforcing material used in the present invention means, for example, unidirectional long fibers such as glass fiber yarns, rovings, and carbon fiber tows, and multidirectional continuous fibers thereof such as woven fabrics, mats, and felts.

These fibrous reinforcing materials include E-glass, S-glass,
Glass fibers such as T-glass, C-glass, and AR-glass; carbon fibers such as polyacrylonitrile, pitch, and rayon; aromatic polyamide fibers such as DuPont's Kevlar; Nippon Carbon's Nicalon, etc. Examples include silicon carbide fibers, metal fibers such as stainless steel fibers, alumina fibers, boron fibers, etc.

These fibrous reinforcing materials may be used alone or in combination.

When selecting a fibrous reinforcing material, it should be selected in accordance with the required properties of the composite material, based on the mechanical properties of the fibers such as strength, modulus of elasticity, and elongation at break, electrical properties, and specific gravity. For example, when specific strength and specific modulus are required to be high, carbon fibers, glass fibers, etc. should be selected, and when electromagnetic shielding properties are required, carbon fibers, metal fibers, etc. are preferable. Furthermore, when electrical insulation properties are required, glass fiber or the like is suitable.

The fiber diameter and number of converging fibers of the male reinforcing material vary depending on the type of fibrous reinforcing material, but for example, in the case of carbon fiber, the fiber diameter is 4 to 8μ and the number of convergence is 1,000 to 1.
2,000 pieces is common. The smaller the fiber diameter, the better from the viewpoint of the mechanical properties of the resulting composite material.

Further, it is preferable to surface-treat the fibrous reinforcing material from the viewpoint of improving the adhesion with polyimide. For example, in the case of glass fiber, it is particularly preferable to treat it with a silane-based or titanate-based coupling agent.

The amount of these fibrous reinforcing materials used is 5 to 85%, preferably 30 to 70%, as a volumetric content in the composite material.

If the volume content of the fibrous reinforcing material is low, the effect of the reinforcing material cannot be expected, and on the other hand, if the volume content is high, the glabellar strength of the resulting composite material will be markedly reduced, which is undesirable.

All known methods can be used to produce a polyimide composite material from polyimide and a fibrous reinforcing material.

Examples include a melt impregnation method in which a fibrous reinforcing material is impregnated with polyimide in a molten state, and a fluidized bed method in which powdered polyimide is impregnated while suspended in air or suspended in a liquid such as water. In the case of the fluidized bed method, heating and melting the polyimide in the fibrous reinforcing material after impregnation and optionally drying is particularly effective for obtaining an integrated polyimide composite material. Further, the particle size at the time of impregnation is preferably smaller than the diameter of the fiber filament used.

Furthermore, a method is also used in which polyimide powder or a film of the polyimide is placed on one or both sides of the fibrous reinforcing material and hot-pressed. At this time, if the fibrous reinforcing material is a woven fabric, the number of woven fabrics and polyimide powder or polyimide film required for the desired thickness of the molded product are alternately laminated and hot-pressed, and impregnation and molding are performed simultaneously. A molded product with uniform resin distribution can be obtained.

Also, as a melt impregnation method, JP-A-61-229534.2
29535.229536 and patent application No. 62-21625
As typically shown in No. 3, there is also a method in which a heating roll or heating belt having a molten resin on its surface is brought into contact with the fibrous reinforcing material to impregnate it.

That is, in this method, unidirectional long fibers pulled out from a plurality of bobbins, such as a fiber sheet with aligned tows or multidirectional continuous fibers, are subjected to a constant tension in the drawing direction using a tension adjustment roll. On the other hand, polyimide is heated and melted in an extruder, and applied from a goo to the lower belt on the surface of a heated roll heated to a predetermined temperature.

Next, the above-described fiber sheet or multidirectional continuous fiber is passed between one or more groups of heated rolls while being sandwiched between a pair of upper and lower belts to be impregnated.

This continuous melt impregnation method is a particularly preferred method.

The composite material obtained as described above can be laminated and heated and compressed to produce a molded product in a desired shape.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 In a reaction vessel equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube, 379 g (1,03 mol) of 4,4'-bis(3-aminophenoxy)diphenyl and N as a solvent were added.
5371 g of N-dimethylacetamide was charged and 217 g of pyromellitic dianhydride was added at room temperature under a nitrogen atmosphere.
8 g (I, 00 mol) was added in portions while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours.・
17.6 g (0,155 mol) of glutaric anhydride was added to this polyamic acid solution at room temperature under a nitrogen atmosphere, and
After stirring for an hour, add 202 g (2 moles) to this solution.
Triethylamine and 306 g (3 mol) of acetic anhydride were added dropwise. Approximately 1 hour after the completion of the dropwise addition, yellow polyimide powder began to precipitate.

After further stirring at room temperature for 10 hours, the slurry was filtered, washed with methanol, and dried at 180°C for 2 hours.
7 g of polyimide powder was obtained. This polyimide powder had a glass transition temperature of 253°C, a melting point of 378°C (based on DSC measurement; the same applies hereinafter), and a logarithmic viscosity of 0.62 dl/g. Here, the logarithmic viscosity is a concentration of 0.5 in a mixed solvent of parachlorophenol/phenol (weight ratio 90/10).
g / 100ml = 35°C after heating and dissolving with solvent
This is the value measured after cooling to .

A composite material was produced from this polyimide and carbon fiber in the following manner. Figure 1 shows an outline of the equipment used for production.

After aligning 2,100 tows of carbon fiber (Besphite HTA-7-3; trademark of Toho Rayon Co., Ltd.) drawn from 100 bobbins 1 in one direction with an aligner 3, tension adjustment rolls 4.5. 6 to obtain a fiber sheet 7 having a width of 150 mm.

On the other hand, polyimide heated and melted in an extruder (not shown) is passed through a die 8 and applied to the surface of the lower belt 10 heated to 420'C by lower belt rolls 9 (three rolls in this case).
It was applied to a thickness of II11. Then, the sheet is rolled 420 times with the lower belt and upper belt rolls 11 (here, 3 rolls).
35 °C while being sandwiched between the upper belt 12 heated to 35 °C.
2 impregnating rolls 13 (here, 3 rolls) with a diameter of 240 mm heated to 0°C while applying a tension of 150 kg.
It was passed at a rate of 0 ports/min. The polyimide/carbon fiber composite material 14 impregnated with polyimide in this manner was cooled and then wound up on a winding shaft via take-up rolls 15, 16, and 17 on one day.

The resulting composite material has a width of 150++ua and a thickness of 0.13m.
It was from m.

Next, 20 sheets of the above polyimide composite material were laminated in one direction and hot pressed at 400'C and 30 kg/d for 20 minutes to obtain a flat plate measuring 200 x 200 mm and 2.5 mm thick.

When the fibrous reinforcement volume percentage (hereinafter referred to as Vt), void ratio, bending strength, and bending elastic modulus of the obtained flat plate were measured,
Vt 60%, void rate 1% or less, bending strength 191Kg/
Good results were obtained with a bending elastic modulus of 12.300 Kg/n+m. Note that Vt and void ratio are values determined from the specific gravity of the flat plate and the weight percentage of the fibrous reinforcing material, and the bending strength and bending elastic modulus are values based on JIS K 7230.

Comparative Example 1 545 g of polyimide powder was obtained in the same manner as in Example 1 except that glutaric anhydride was not used. The logarithmic viscosity of the obtained polyimide powder was 0.52 dl/g.

Using the thus obtained polyimide, a polyimide composite material was obtained in the same manner as in Example 1. Composite material Example 1
It was molded in the same manner as above, and its physical properties were evaluated: Vt 60%, void ratio 7.3%, bending strength 91 Kg/am", bending modulus 5,
The fluidity of the polyimide was extremely low at 500 Kg/mm'', and the defoaming was insufficient, resulting in low strength and elastic modulus at the 8i end.

Reference Example 1゜Using the polyimide powder obtained in Example 1 and Comparative Example 1, a Koka type flow tester (Shimadzu Corporation, CFT-500) was used.
, orifice diameter 0.1 cm, length 1 cI11), and the relationship between melt viscosity and shear rate was measured.

FIG. 2 shows the relationship between melt viscosity and shear rate measured at various shear rates after being maintained at a temperature of 420'C for 5 minutes.

Examples 2 to 5 Polyimide composite materials were obtained in the same manner as in Example 1, except that the type of fibrous reinforcing material and the thickness of polyimide applied to the belt were changed as shown in the table.

Next, the obtained composite material was laminated in one direction in the number shown in the table, and then operated in the same manner as in Example 1 to obtain a flat plate.

The physical properties of the obtained flat plate are shown in the table.

Examples 6-7 Example 1 except that the type of fibrous reinforcing material and the thickness of polyimide coating on the belt were changed as shown in the table, and the tension was changed to 30 kg.
A polyimide composite material was obtained in exactly the same manner as above. Then, after laminating the obtained composite material in the number of sheets shown in the table, Example 2
A flat plate was obtained in the same manner as above. The physical properties of the obtained flat plate are shown in the table.

Example day: 1.0 m thick on top of a 50 μm thick heat-resistant release film.
m, place an aluminum picture frame with inner dimensions of 30cm x 30Ω,
5 g of the polyimide powder obtained in Example 1 was uniformly dispersed within the frame on the film. Then, after removing the frame, 30c
m+X30cn+ carbon fiber woven fabric (Besphite w −
3101; manufactured by Toho Rayon Co., Ltd.) was placed on the polyimide cloth, and further, 5 g of polyimide powder was uniformly dispersed on the woven cloth. Next, after placing a commercially available heat-resistant mold release film on it, it was transferred to the lower mold at 400°C, the mold was closed, and the temperature was heated at 400°C.
It was heated and compressed for 10 minutes at 170 kg/c. The mold was then cooled under pressure to 250''C, the mold was opened, the contents were taken out and the heat-resistant film was peeled off to obtain a composite material.The composite material thus obtained was then divided into six parts and laminated. Thereafter, a flat plate was obtained by molding under the same conditions as in Example 1. The Vt, bending strength, and bending modulus of the obtained flat plate were each 60%.
, 82Kg/ll5”, 6.300Kg/m*”T
! On the day of the example, 412 g (I, 03 mol) of bis(4-(3-aminophenoxy)phenyl) sulfide was added to the same apparatus as in Example 1.
and 5747 g of N,N-dimethylacetamide were charged, and 217 g of pyromellitic dianhydride was added at room temperature under a nitrogen atmosphere.
g (I, 0 mol) and 9.53 g (0,062 mol) of 1,2-cyclohexanedicarboxylic anhydride were added while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours.

Next, 202 g (2 moles) of triethylamine and 306 g (3.0 moles) of acetic anhydride were added dropwise to this solution, and the mixture was stirred at room temperature for 20 hours to obtain a pale yellow slurry. This slurry was filtered, washed with methanol, and heated to 180°C.
The mixture was dried under reduced pressure for 8 hours to obtain 597 g of pale yellow polyimide powder. The glass transition temperature of this polyimide powder is 232°C
The 5-log viscosity was 0.49 dl/g. The resulting polyimide had a melt viscosity of 5,600 poise, as measured using a Koka type flow tester in the same manner as in Example 1, at a cylinder temperature of 320°C, residence time of 5 minutes, and pressure of 100/cffl.

Using the polyimide obtained in this way, the impregnation temperature was set to 3.
A composite material was obtained by processing in the same manner as in Example 1 except that the temperature was changed to 40°C. Then, a flat plate was obtained by hot pressing in the same manner as in Example 1 except that the molding temperature was changed to 320°C. The bending strength and bending elastic modulus of the obtained flat plate were each 180 kg/m.
m", 11,100 Kg/mm".

Comparative Example 2 A pale yellow polyimide powder was obtained in the same manner as in Example 9, except that 1.2-cyclohexanedicarboxylic anhydride was not used. The glass transition temperature of polyimide powder is 235°C
The logarithmic viscosity was 0.49 dl/g.

Flow tester cylinder temperature 42 as in Example 9
The melt viscosity measured at 0°C1 residence time of 5 minutes and a pressure of 100/cJ was 8000 poise. - Using the thus obtained polyimide, a polyimide composite material was obtained in the same manner as in Example 9. The composite material was molded in the same manner as in Example 9, and its physical properties were evaluated: Vt: 60%, void ratio: 5.8%, bending strength: 90 K g/m Im'', bending modulus: 5
, 800Kg/'lll11'', the fluidity of the polyimide was extremely low and defoaming was insufficient, resulting in extremely low strength and elastic modulus.

Reference Example 2 Using the polyimide powder obtained in Example 9 and Comparative Example 2, the thermal stability was tested using the same flow tester as in Reference Example 1 at a temperature of 320° C. and a pressure of 100 kg/cm. The relationship between residence time in the cylinder and melt viscosity was measured.The results are shown in FIG.

In the case of the polyimide powder obtained in Example 9, the melt viscosity hardly changes even if the residence time in the cylinder becomes long and the thermal stability is excellent, whereas in the case of the polyimide powder obtained in Comparative Example 2 It can be seen that as the residence time becomes longer, the melt viscosity increases and the thermal stability deteriorates.

Example 10 In the same apparatus as in Example 1, 400 g (I, 01 mol) of bis(4-(3-aminophenoxy)phenyl fuketone) and 310 g (I, 4000 g of m-
It was charged together with cresol, and the temperature was gradually increased while stirring under a nitrogen atmosphere. It became a brown transparent homogeneous solution at around 120"C. When the temperature was raised to 150°C and stirred at this temperature for about 20 minutes, yellow polyimide powder began to precipitate. Stirred for further 2 hours at this temperature. This polyimide powder was washed with methanol and acetone, and then dried under reduced pressure at 180°C for 8 hours to obtain 676 g of polyimide powder.The logarithmic viscosity of this polyimide powder was 0. 85 dl/g, glass transition temperature is 2
It was 00°C.

Using the polyimide obtained in this way, the impregnation temperature was set to 320°C.
A composite material was obtained in the same manner as in Example 1 except that the temperature was changed to °C. Example 1 except that the molding temperature was then changed to 300°C.
The bending strength and bending elastic modulus of the obtained flat plate obtained by hot pressing in the same manner as 173 Kg/as",
10,300 g/am”.

〔Effect of the invention〕

According to the method of the present invention, a novel polyimide-based composite material which not only has the excellent properties originally possessed by polyimide but also has extremely good moldability is provided.

[Brief explanation of the drawing]

FIG. 1 shows an example of an apparatus for manufacturing a polyimide composite material. Figure 2 shows the relationship between the melt viscosity (voids) and shear rate of the polyimide used in the present invention, and Figure 3 shows the relationship between the residence time in the flow tester cylinder and the melt viscosity of the polyimide used in the present invention. , are separate diagrams showing each. Patent applicant: Mitsui Toatsu Kagaku Co., Ltd. Procedural amendment (method) March 18, 1988 Director General of the Patent Office Kunio Ogawa 1, Indication of the case 1988 Patent Application No. 295316 2, Name of the invention Polyimide system Composite Materials 3, Relationship with the Amendment Person Case Patent Applicant Address 3-2-5 Kasumigaseki, Chiyoda-ku, Tokyo Name (31
2) Mitsui Toatsu Kagaku Co., Ltd. 4. Date of amendment order: February 23, 1988 (Shipping mortar) 6. Subject of amendment

Claims (1)

[Claims] In a polyimide-based composite material consisting of polyimide and a fibrous reinforcing material, the polyimide is represented by the formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (wherein, X is a direct link, Represents a group selected from the group consisting of a divalent hydrocarbon group having 1 to 10 carbon atoms, a hexafluorinated isopropylidene group, a carbonyl group, a thio group, or a sulfonyl group, and Y_1, Y_2, Y_3 and Y_4 are Each represents a group selected from the group consisting of hydrogen, a lower alkyl group, a lower alkoxy group, chlorine or bromine, and R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group,
It represents a tetravalent group selected from the group consisting of a fused polycyclic aromatic group and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. ) The repeating unit is the basic skeleton, and the polyimide has the formula (
II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R is the same as before) 1.0 molar ratio of tetracarboxylic dianhydride ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) (wherein X, Y_1, Y_2, Y_3 and Y_4 are the same as before) and ether diamine 1.0 to 1 represented by formula (III)
．． 5 molar ratio, and in the presence of an aliphatic and/or alicyclic dicarboxylic acid anhydride represented by formula (IV) in a 0.001 to 1.0 molar ratio, thermally or chemically A polyimide composite material characterized by being a polyimide obtained by imidization ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (IV) (In the formula, Z is an aliphatic group having 1 to 10 carbon atoms and /
Or it represents a divalent group consisting of a cycloaliphatic group. )