JPH0681802B2 - Carbon fiber reinforced polyimide resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a carbon fiber reinforced polyimide resin composition having excellent mechanical strength.

[Conventional technology]

The thermoplastic polyimide resin represented by Ultem (registered trademark of GE) is superior to general-purpose engineering plastics in terms of heat resistance and mechanical strength, and is called super engineering plastic. Widely studied for applications such as automobiles.

Recently, along with technological advances, development of new thermoplastic polyimide resins having heat resistance and mechanical properties higher than Ultem is required.

For example, a method for producing a polyimide resin obtained by reacting ether diamine and tetracarboxylic dianhydride is disclosed in U.S. Pat.No. 4,847,349, and 3,3'-diaminobenzophenone and tetracarboxylic dianhydride are prepared. The method for producing the polyimide resin obtained by the reaction is also Japanese Patent Application 167392 (19
89) etc. All of them provide a novel polyimide resin having heat resistance and mechanical properties which are not available in the past.

In order to further enhance the properties of these polyimide resins, especially the mechanical strength, a fibrous reinforcing material, particularly carbon fiber, is generally added. However, since carbon fibers are often used in carbon fiber reinforced plastics having an epoxy resin as a matrix, an epoxy resin is usually used as a sizing agent for carbon fibers. Therefore, when the thermosetting resin such as the epoxy resin is the matrix, the epoxy resin sizing agent is effective, but the adhesiveness to the polyimide resin is poor, and a resin composition having good mechanical strength cannot be obtained. . Further, for example, as seen in JP-A-53-106752,
There is also a method of using a polyamide resin as a sizing agent for carbon fibers, but generally at least 300 ° C for molding a polyimide resin.
Since the above-mentioned high temperature is required, the sizing agent is thermally decomposed during the molding, which causes problems such as the formation of voids and the reduction of the weld strength.

Further, as seen in Japanese Unexamined Patent Publication (Kokai) No. 56-120730, there is a method of using carbon fibers bundled with an aromatic polysulfone resin, but the improvement in mechanical strength is small and the required characteristics have not been sufficiently satisfied. .

[Means for solving problems]

The present inventors have variously studied carbon fiber reinforced polyimide resin composition, after applying an aromatic polysulfone resin as a sizing agent on the surface, by blending the carbon fiber heated at 300 ~ 400 ° C. with the polyimide resin The inventors have found that the above objects can be achieved and completed the present invention.

That is, the present invention is used as a sizing agent in 0.1 to 100 parts by weight of carbon fiber.
Carbon fiber reinforced consisting of 5 to 50 parts by weight of carbon fiber obtained by applying 10 parts by weight of aromatic polysulfone resin on the surface of carbon fiber and then heating at 300 to 400 ° C. and 95 to 50 parts by weight of polyimide resin It is a polyimide resin composition.

The polyimide resin used in the present invention is selected from thermoplastic polyimide resins having repeating units of formulas (I) and (II).

(In the formula, X is a direct bond, a divalent hydrocarbon group having 1 to 10 carbon atoms,
Represents a group selected from the group consisting of a hexafluorinated isopropylpyridene group, a carbonyl group, a thio group, and a sulfonyl group, and R represents an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic group It represents a tetravalent group selected from the group consisting of an aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which the aromatic groups are connected to each other directly or by a bridging member. The logarithmic viscosity of the polyimide resin powder represented by the above formula (I) is usually 0.20 to 0.70 dl / g, preferably 0.30 to 0.60. If it is less than 0.20, it is difficult to obtain the desired mechanical properties, and if it is more than 0.70, the melt viscosity becomes high and the moldability becomes poor.

The logarithmic viscosity shown here is 0.5g / 100ml in a mixed solvent of parachlorophenol / phenol (weight ratio 90/10).
It is the value measured by dissolving in a solvent with heating and then cooling to 35 ° C.

The logarithmic viscosity of the polyimide resin powder represented by the above formula (II) is usually 0.25 to 0.75 dl / g, preferably 0.35 to 0.65. If it is less than 0.25, it is difficult to obtain the desired mechanical properties, and if it is more than 0.75, the melt viscosity becomes high and the moldability becomes poor.

The polyimide resin represented by the above formula (I) has the formula (II
An etherdiamine represented by I) is used, which is synthesized by dehydrating and cyclizing a polyamic acid obtained by reacting this with one or more tetracarboxylic dianhydrides represented by the formula (IV). It is polyimide. Specifically, it can be easily prepared by the method disclosed by US Pat. No. 4,847,349.

(In the formula, X is the same as before) (Wherein R is the same as before) The etherdiamine of the formula (III) used in this method includes 4,4′-bis [4- (3-aminophenoxy) phenyl] sulfide, 4,4′- Bis [4- (3-aminophenoxy) phenyl] sulfone, 4,4'-bis (3-aminophenoxy) benzophenone, 4,4'-bis (3-aminophenoxy) biphenyl, bis [4- (3-amino Phenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-Aminophenoxy) phenyl] butane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexyfluoropropane, bis [4- (3 -Aminophenoxy) phenyl] ketone, etc., which may be used alone or in combination with 2
Used as a mixture of two or more species.

Further, other diamines can be mixed and used within a range that does not impair the melt fluidity of the thermoplastic polyimide resin. As the diamine that can be mixed and used,
m-aminobenzylamine, p-aminobenzylamine, 3,
3'-diaminodiphenyl ether, 3,4'-diaminophenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone , 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,
4-bis (3-aminophenoxy) benzene, 1,4-bis (4-
Aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) phenyl ] Ketone, bis [4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfone, etc., and these diamines are usually mixed in an amount of 30 wt% or less, preferably 5 wt% or less. Used.

Examples of the tetracarboxylic acid dianhydride of the formula (IV) used in this method include ethylene tetracarboxylic acid dianhydride, butane tetracarboxylic acid dianhydride, cyclopentane tetracarboxylic acid dianhydride and pyromellitic acid dianhydride. Anhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride Substance, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4- Dicarboxyphenyl)-
1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride Anhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic acid dianhydride, 3,3 ', 4,4'-biphenyl Tetracarboxylic acid dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) Ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 4,4 '-(p-phenylenedioxy) diphthalic acid dianhydride, 4,4'-(m-phenylenedioxy) Diphthalic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic Acid dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracene tetracarboxylic acid dianhydride Examples thereof include anhydrides and 1,2,7,8-phenanthrenetetracarboxylic dianhydride. These tetracarboxylic dianhydrides may be used alone or in admixture of two or more.

The amount of the tetracarboxylic acid dianhydride is the diamine 1
It is in the range of 0.9 to 1.0 mole ratio with respect to moles.

The polyimide resin represented by the above formula (II) is obtained by reacting the 3,3′-diaminobenzophenone represented by the formula (V) with the tetracarboxylic dianhydride represented by the above formula (IV). The obtained polyamic acid is thermally or chemically imidized to be synthesized.

In the production of the polyimide resin represented by the above formula (II), it is preferable to carry out the reaction in the presence of a relatively small amount of the dicarboxylic acid anhydride represented by the formula (VI).

(In the formula, Z is selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which the aromatic groups are connected to each other directly or by a bridging member. Represents a divalent group.) The polyimide resin represented by the above formula (II) is represented by Japanese Patent Application No. 1673.
92 (1989) and the like. In the reaction, the amount of tetracarboxylic dianhydride is
It is in the range of 0.9 to 1.0 mol per mol of diamine, and the amount of dicarboxylic anhydride is 0.001 per mol of diamine.
The range is from 1.0 to 1.0 mol, preferably from 0.01 to 0.2 mol.

As the tetracarboxylic dianhydride represented by the formula (IV) used for producing the polyimide resin represented by the formula (II), the above-exemplified compounds are similarly used.

The dicarboxylic acid anhydride used in a relatively small amount, for example, phthalic anhydride, 2,3-benzophenone dicarboxylic acid anhydride, 3,4-benzophenone dicarboxylic acid anhydride, 2,3-
Dicarboxyphenyl phenyl ether anhydride, 3,4-dicarboxyphenyl phenyl ether anhydride, 2,3-biphenyl dicarboxylic acid anhydride, 3,4-biphenyl dicarboxylic acid anhydride, 2,3-dicarboxyphenyl phenyl sulfonic acid Anhydride, 3,4-dicarboxyphenyl phenyl sulfonic anhydride, 2,3-dicarboxyphenyl sulfide anhydride, 3,4-dicarboxyphenyl phenyl sulfide anhydride, 1,2-naphthalenedicarboxylic anhydride, 2 , 3-naphthalenedicarboxylic acid anhydride, 1,8-naphthalenedicarboxylic acid anhydride, 1,2-anthracene dicarboxylic acid anhydride, 2,3-anthracene dicarboxylic acid anhydride, 1,9-anthracene dicarboxylic acid anhydride, etc. Is mentioned. These may be used alone or in combination of two or more.

In the production of the polyimide resin represented by the formula (I) and the formula (II) of the present invention, a range that does not impair the good properties of the polyimide resin of the present invention, for example, usually 30% by weight or less of the amount of the diamine, preferably Can be used by substituting with another diamine within the range of 5% by weight or less.

Examples of aromatic diamines that can be partially substituted include, for example, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine,
p-aminobenzylamine, bis (3-aminophenyl) ether, (3-aminophenyl) (4-aminophenyl) ether, bis (4-aminophenyl) ether, bis (3-
Aminophenyl) sulfide, (3-aminophenyl)
(4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 3,4'-diaminobenzophenone,
4,4'-diaminobenzophenone, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4 -Aminophenoxy) phenyl] ethane, 2,2-bis [4- (4-
Aminophenoxy) phenyl] propane, 2,2-bis [4-
(4-Aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-
Hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4 -Aminophenoxy) benzene, 4,4'-bis (4-
Aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4 -(4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-
Aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-
Bis [4- (3-aminophenoxy) phenyl] ethane, 2,
2-bis [4- (3-aminophenoxy) phenyl] propane, 2- [4- (3-aminophenoxy) phenyl] -2- [4-
(3-Aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (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 〔Four-
(3-Aminophenoxy) phenyl] butane, 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) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) -3-methoxyphenyl] sulfide , [4- (3-aminophenoxy) phenyl] [4- (3-aminophenoxy) -3,5-dimethoxyphenyl] sulfide, bis [4-
(3-Aminophenoxy) -3,5-dimethoxyphenyl] sulfide, bis [4- (3-aminophenoxy) phenyl]
Examples thereof include sulfone.

In the present invention, the aromatic polysulfone resin used for coating the surface of the carbon fiber as a sizing agent is a linear polymer having an arylene bond, an ether bond and a sulfone bond as a bonding unit, and is represented by, for example, the following formula: It is known to consist of various structural units.

These aromatic polysulfone resins are, for example, Japanese Patent Publication No. 40-1
It can be produced by the method described in JP-B No. 0067, JP-B-42-7799, and JP-B-47-617, and one or more of them can be used.

For example, in the polymer (1) above, dichlorodiphenyl sulfone, an aqueous sodium sulfide solution and dimethyl sulfoxide are stirred in N ₂ at 150 ° C. for 5 hours. Then, benzene is added to remove all water azeotropically, and benzene is further removed by distillation. Then, the remaining mixture is heated with stirring at 170 ° C. for 7 hours to obtain a polymer.

The polymer of (2) above neutralizes bisphenol A with KOH in N ₂ using benzene and DMSO as solvents, and removes the produced water by azeotroping with benzene. DMSO solution of
-Add dichlorodiphenyl sulfone and add 4-5 at 135 ℃.
Synthesized by polycondensation over time.

The polysulfone resin represented by the structural unit (1) is commercially available, for example, under the trade name of "Victorrex, polyethersulfone PES 5003" manufactured by Imperial Chemical Industries.

As a typical example represented by the structural unit of (2), there is "Udel Polysulfone (trademark)" of Amoco Chemical Co., USA.

Examples of the carbon fiber include acrylic type, rayon type, lignin type, pitch type and the like, and any of them can be used in the present invention. In the present invention, the acrylic resin having the highest fiber strength is most preferably used. The form of the carbon fiber may be any of chopped strand, roving, woven fabric, and the like. It is more preferable to oxidize the surface of these carbon fibers in advance by ozone or electrolytic oxidation.

As a method for applying an aromatic polysulfone resin to these carbon fibers, an aromatic polysulfone resin is prepared by using dichloromethane,
Add carbon to a solution dissolved in a solvent such as chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dimethyl sulfoxide, N-methyl-pyrrolidone, methyl ethyl ketone, 1,1,2-trichloroethane. The fibers are dipped and then dried to remove the solvent to obtain carbon fibers coated with the aromatic polysulfone resin.

The amount of the aromatic polysulfone resin applied to the carbon fibers is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 9 parts by weight and further preferably 1 to 8 parts by weight, based on 100 parts by weight of the applied carbon fibers. 0.1
If it is less than 10 parts by weight, the effect of the present invention cannot be obtained, and if it exceeds 10 parts by weight, further improvement in mechanical strength cannot be expected, which is meaningless.

The heat treatment of the carbon fiber coated with the aromatic polysulfone resin as described above is 300 to 400 ° C. in air, and particularly preferably
It is carried out by exposing it to a temperature of 340 to 380 ° C. The heat treatment time is 3 to 20 hours, particularly preferably 5 to 15 hours. If the temperature is lower than 300 ° C, it takes a long time for the heat treatment effect to be exhibited. On the other hand, if the temperature is higher than 400 ° C, the impregnated carbon fiber is significantly deteriorated due to heat, and desired mechanical properties cannot be obtained.

Various methods can be adopted as a method for mixing the carbon fiber coated with the aromatic polysulfone resin thus obtained and the polyimide resin. For example, the coated and heat-treated carbon fibers may be cut into a length of 3 to 6 mm, and the polyimide resin and the polyimide resin may be separately fed to a melt extruder and mixed, or a Henschel mixer, a super mixer, a ribbon blender, etc. It is also possible to pre-blend with the above mixer and then feed to the melt extruder. Further, it is also possible to directly supply the carbon fiber roving coated and heat-treated to the melt extruder and mix it with the polyimide resin.

In the present invention, the blending ratio of the carbon fiber heat-treated by coating the aromatic polysulfone resin and the polyimide resin as the matrix resin is 5 to 50 parts by weight of carbon fiber, preferably
10 to 50 parts by weight, polyimide resin 95 to 50 parts by weight, preferably 90 to 50 parts by weight. When the compounding amount of carbon fiber is less than 5 parts by weight, the tensile strength of the obtained resin composition is low, which is not preferable. Further, when the carbon fiber is blended in an amount of more than 50 parts by weight, uniform melt mixing of the obtained resin composition becomes difficult, and the melt fluidity is remarkably reduced, resulting in impairing moldability such as injection molding. Become.

In the present invention, if necessary to the above polyimide resin composition, talc, calcium carbonate, mica, filler such as glass beads, glass fiber, potassium titanate fiber, aramid fiber, fibrous reinforcing material such as ceramic fiber, stabilizer The colorant may be mixed in a range that does not impair the quality and performance of the resin composition of the present invention.

The resin composition of the above-described improved carbon fiber and polyimide resin of the present invention can be molded into a predetermined molded article by a known molding method such as an injection molding method, an extrusion molding method, a transfer molding method, or a compression molding method. . The resin composition of the present invention molded in this manner has excellent mechanical strength, particularly mechanical strength at high temperatures, and therefore mechanical parts that require high mechanical strength at high temperatures, automobile parts such as gears and cams. , Bushings, pulleys, sleeves, etc., and as internal combustion engine parts, impellers for integrated centrifugal compressors, exhaust system parts for silencers such as manifolds, valve guides, valve stems, piston skirts, oil pans, front covers, It can be used for rocker covers.

The carbon fiber reinforced polyimide resin composition according to the present invention is a pellet-like molding material which is usually easy to handle, and a product is manufactured by injection molding. At this time, pelletization is achieved by kneading and extruding the polyimide resin and carbon fiber strands using a known uniaxial or biaxial extruder, and then cutting.

The injection molding of the obtained pellets can be carried out using an ordinary injection molding machine at a cylinder temperature of 360 to 420 ° C and a mold temperature of 160 to 210 ° C, preferably 180 to 200 ° C. Parts such as impellers for integrated centrifugal compressors can also be easily obtained.

The carbon fiber reinforced polyimide resin composition according to the present invention has excellent mechanical strength and is used as a material for parts in all industrial fields such as electric / electronic devices, machines, automobiles, aviation, space equipment, and general industrial equipment. Since it can be widely used, its industrial value is great.

Hereinafter, the present invention will be further described with reference to Synthesis Examples, Examples and Comparative Examples.

(Synthesis example) 21.8 kg (100 mol) of pyromellitic dianhydride and 38.3 kg of N, N'-dimethylacetamide were inserted into a reaction vessel equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, and 4 , 4'-Bis (3-aminophenoxy) biphenyl 3.5
7 kg (9.7 mol) was added in portions while paying attention to the rise in solution temperature, and the mixture was stirred at room temperature for about 20 hours.

Then 2.0 kg (20 mol) of triethylamine and 25.5 kg (250 mol) of acetic anhydride were added dropwise to this solution. About 1 hour after the completion of dropping, yellow polyimide powder began to precipitate.
After further stirring at room temperature for 10 hours, the slurry was filtered off, washed with methanol, and dried at 180 ° C. for 2 hours to obtain 51.1 kg of polyimide powder. The logarithmic viscosity of this polyimide powder is 0.42
It was dl / g. Logarithmic viscosity is 0.5g / 100ml in a mixed solvent of parachlorophenol / phenol (weight ratio 90/10)
It is the value measured by dissolving in a solvent with heating and then cooling to 35 ° C.

Examples 1 to 20 "Victrex Polyethersulfone PES 5003P (trademark)" from Imperial Chemical Industries, Inc., 20% by weight, dichloromethane 40% by weight, 11,1,2-
A polyethersulfone solution consisting of 40% by weight of trichloroethane was prepared. Roving of this acrylic sulfone solution surface-oxidized acrylic carbon fibers (manufactured by Toho Rayon Co., Ltd., trade name HTA, in the following examples and comparative examples, carbon fibers were used except for special mention) After continuous immersion at a speed of 60 m / Hr, drying and solvent removal, the product was cut into a length of 3 mm to obtain chopped strands.

At this time, the amount of the aromatic polyether sulfone resin attached to the carbon fibers was 5% by weight.

This carbon fiber chopped strand was placed in a stainless steel vat, placed in an electric furnace heated to 350 ° C., and heat-treated in an air atmosphere for 10 hours.

The carbon fiber chopped strands thus obtained and the polyimide resin obtained in the synthesis example were dry blended in the proportions shown in Table 1 and then extruded at an extrusion temperature of 40 mm with an extruder of 40 mm diameter.
An extrusion operation was performed while melt-kneading at 0 ° C. to obtain uniformly mixed pellets.

Next, using the usual injection molding machine to make a dumbbell test piece from the above uniform pellets under the temperature conditions of a cylinder temperature of 410 ° C and a mold temperature of 200 ° C, the tensile strength at a temperature of 23 ° C and a pulling speed of 5 mm / min. The measurement was performed and the results are shown in Table 1.

Example 4 In Example 2, the carbon fiber chopped strands coated with the aromatic polyether sulfone resin were placed in a stainless steel vat, placed in an electric furnace heated to 370 ° C., and heat-treated in an air atmosphere for 8 hours. A dumbbell test piece of a carbon fiber-blended polyimide resin was prepared in the same manner as in Example 2 except that the test was carried out, and the tensile strength was measured in the same manner.
Shown in the table.

Example 5 4,4′-Bis [4- (3-aminophenoxy) phenyl) sulfide as Component (III) 3,3 ′ as Component (IV),
Using 4,4'-biphenyltetracarboxylic dianhydride as a raw material, polyimide powder with an inherent viscosity of 0.40 dl / g was obtained.

Next, the heat-treated carbon fiber chopped strands obtained in Example 1 and this polyimide resin were dry-blended in a ratio shown in Table 1, and then melt-kneaded in a 40 mm diameter extruder at an extrusion temperature of 400 ° C. While carrying out extrusion operation, uniform blended pellets were obtained.

Next, using the usual injection molding machine, a dumbbell test piece is prepared from the above-mentioned uniformly compounded pellets under the temperature conditions of a cylinder temperature of 410 ° C. and a mold temperature of 200 ° C., a temperature of 23 ° C., a pulling speed of 5 mm /
The tensile strength was measured in minutes, and the results are shown in Table 1.

Comparative Examples 1 to 3 In addition to the carbon fiber chopped strands coated with the aromatic polyether sulfone resin and heat-treated in Examples 1 to 3, the acrylic carbon fibers bundled with the epoxy resin were used without being heat-treated. A dumbbell test piece of a carbon fiber-blended polyimide resin was prepared in the same manner as in 1, and the tensile strength was measured in the same manner, and the results are shown in Table 1.

Comparative Examples 4 to 6 The carbon fiber chopped strands coated with the aromatic polyether sulfone resin and heat-treated in Examples 1 to 3 were used in place of the heat-treated acrylic carbon-maintained carbonaceous sulphate resin. Other than that, a dumbbell test piece of a carbon fiber-blended polyimide resin was prepared in the same manner as in Examples 1 to 3, and the tensile strength was measured. The results are shown in Table 1.

Comparative Example 7 Carbon fiber chopped strands coated with an aromatic polyether sulfone resin and heat-treated in Example 1 were dry-blended at a ratio shown in Table 1 and then extruded with a 40 mm diameter extruder. The same procedure as in Example 1 was performed except that the operation of extruding while melting and kneading at a temperature of 410 ° C. was performed. The feedability to the extruder feed section was poor, and the surging phenomenon was remarkable.

The obtained pellets had poor melt flowability, and dumbbell test pieces could not be prepared by injection molding.

Comparative Example 8 In Example 1, carbon fiber chopped strands coated with an aromatic polyether sulfone resin and heat-treated were dry blended at a ratio shown in Table 1 and then extruded with a 40 mm diameter extruder. An operation of extruding while melting and kneading at a temperature of 410 ° C. was performed to obtain pellets having a uniform composition.

Next, using a normal injection molding machine, a dumbbell test piece is prepared from the above-mentioned homogeneously blended pellets under the conditions of a cylinder temperature of 410 ° C and a mold temperature of 200 ° C, and the tensile strength at a temperature of 23 ° C and a pulling speed of 5 mm / min. The measurement was performed and the results are shown in Table 1.

Examples 6-8 3,3'-diaminobenzophenone 10 as component (V)
Moles and 9.7 moles of 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride as component (IV) and component (VI)
As a raw material, 1.5 log of phthalic anhydride
0.46 dl / g of polyimide powder was obtained.

Next, a polyethersulfone solution consisting of 20% by weight of Victorex polyethersulfone PES5003P (trademark) of Imperial Chemical Industries, 40% by weight of dichloromethane, and 40% by weight of 1,1,2-trichloroethane is prepared. Prepared. A roving of acrylic carbon fiber (trade name: HTA, manufactured by Toho Rayon Co., Ltd.) whose surface is oxidized in this polyethersulfone solution is continuously immersed at a speed of 60 m / Hr, dried and desolvated, and then 3 mm long Cut into
It was chopped strand.

At this time, the amount of the aromatic polyether sulfone resin attached to the carbon fibers was 5% by weight.

This carbon fiber chopped strand was placed in a stainless steel vat, placed in an electric furnace heated to 350 ° C., and heat-treated in an air atmosphere for 10 hours.

The carbon fiber chopped strands thus obtained and the polyimide resin were dry blended in the proportions shown in Table 2 and then extruded with a 40 mm diameter extruder at an extrusion temperature of 360 ° C. while melt-kneading. A uniform blended pellet was obtained.

Next, using the usual injection molding machine, a dumbbell test piece is prepared from the above homogeneously mixed pellets under the conditions of a cylinder temperature of 380 ° C and a mold temperature of 180 ° C, and the tensile strength at a temperature of 23 ° C and a pulling speed of 5 mm / min. The measurement was performed and the results are shown in Table 2.

Example 9 In Example 7, the carbon fiber chopped strands coated with the aromatic polyether sulfone resin were placed in a stainless steel vat and then placed in an electric furnace heated to 370 ° C.
A dumbbell test piece of a carbon fiber-blended polyimide resin was prepared in the same manner as in Example 7 except that the heat treatment was performed in an air atmosphere, and the tensile strength was measured in the same manner, and the results are shown in Table 2. It was

Example 10 3,3'-diaminobenzophenone as component (V) 3,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride as component (IV) and 3,4 as component (VI) -Using benzophenone tetracarboxylic dianhydride as a raw material,
A polyimide powder having a logarithmic viscosity of 0.50 dl / g was obtained.

Next, the heat-treated carbon fiber chopped strands obtained in Example 6 and this polyimide resin were dry-blended at the ratio shown in Table 2, and then melt-kneaded at an extrusion temperature of 370 ° C. in a 40 mm diameter extruder. While carrying out extrusion operation, uniform blended pellets were obtained.

Next, using a normal injection molding machine, a dumbbell test piece is prepared from the above homogeneously blended pellets under the conditions of a cylinder temperature of 390 ° C. and a mold temperature of 180 ° C., and a tensile strength at a temperature of 23 ° C. and a pulling speed of 5 mm / min. The measurement was performed and the results are shown in Table 2.

Comparative Examples 9 to 11 Examples except that the carbon fiber chopped strands coated with the aromatic polyether sulfone resin and heat-treated in Examples 6 to 8 were replaced with acrylic carbon fibers bundled with an epoxy resin without heat treatment A dumbbell test piece of carbon fiber-blended polyimide resin is prepared in the same manner as in 6,
Similarly, the tensile strength was measured and the results are shown in Table 2.

Comparative Examples 12 to 14 In place of the carbon fiber chopped strands coated with the aromatic polyether sulfone resin and heat-treated in Examples 6 to 8, the acrylic carbon fibers bundled with the aromatic polyether sulfone resin were used without heat treatment. Other than that, a dumbbell test piece of a carbon fiber-blended polyimide resin was prepared in the same manner as in Examples 6 to 8, and the tensile strength was measured in the same manner, and the results are shown in Table 2.

Comparative Example 15 The carbon fiber chopped strands which were coated with the aromatic polyether sulfone resin and heat-treated in Example 6 were dry-blended at the ratio shown in Table 2 and then extruded at a 40 mm diameter extruder. The same procedure as in Example 6 was performed except that the extrusion was performed at 390 ° C. while melt-kneading. The feedability to the extruder feed section was poor, and the surging phenomenon was remarkable.

The obtained pellets had poor melt flowability, and dumbbell test pieces could not be prepared by injection molding.

Comparative Example 16 The carbon fiber chopped strands obtained by coating and heat-treating the aromatic polyether sulfone resin in Example 6 were dry-blended in the proportions shown in Table 2 and then extruded at a 40 mm diameter extruder. An extrusion operation was carried out while melt-kneading at 350 ° C. to obtain a uniformly mixed pellet.

Next, using the usual injection molding machine, a dumbbell test piece is prepared from the above-mentioned homogeneously blended pellets under the conditions of a cylinder temperature of 370 ° C and a mold temperature of 170 ° C, and the tensile strength at a temperature of 23 ° C and a pulling speed of 5 mm / min. The measurement was performed and the results are shown in Table 2.

Comparative Examples 17-18 The heat treatment conditions of 350 degreeC and 10 hours in Example 2 are 280 degreeC,
10 hours and 250 ° C., where except for changing the 10 hour tests were conducted in the same manner, each tensile strength of the dumbbell specimens by both conditions 2220Kg / cm ² and 2160Kg / cm ²
And 2640 Kg / cm ^{2 of} Example 2 at 350 ° C. for 10 hours
It was significantly inferior.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-253655 (JP, A) JP-A-61-95067 (JP, A) JP-A-62-220530 (JP, A) JP-A-2- 175972 (JP, A)

Claims (1)

[Claims] 1. A carbon fiber of 5 to 50 parts by weight obtained by applying an aromatic polysulfone resin in an amount of 0.1 to 10 parts by weight to 100 parts by weight of carbon fiber and then heating at 300 to 400 ° C. A carbon fiber reinforced polyimide resin composition comprising 95 to 50 parts by weight of a polyimide resin having a repeating unit of the following formula (I) or formula (II). Formula (I) Or formula (II) (In the formula, X is a direct bond, a divalent hydrocarbon group having 1 to 10 carbon atoms,
Hexafluorinated isopropylidene group, carbonyl group,
Represents a group selected from the group consisting of a thio group and a sulfonyl group, R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group,
A tetravalent group selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which aromatic groups are directly or linked to each other by a bridging member. Represent. )