Abstract: A process for preparing a molded article of fiber-reinforced plastic having an optional configuration and no tendency to deformation and cracks by using a plate material consisting essentially of a fibrous reinforcement and a thermoplastic resin, comprising the steps of previously setting-up, on the plate material and/or a mold, a sheet prepreg obtained by impregnating a unidirectionally arranged fiber or woven cloth with a thermoplastic resin in areas where the fibrous reinforcement does not follow the flow of the resin well or in areas where special reinforcement is required and successively carrying out integral molding to obtain said article; and a molded article obtained by said process.

Abstract: A polyimide resin composition is disclosed herein which comprises 5 to 60% by weight of a polyimide [polyimide (1)] having a repeating unit represented by the chemical formula 1 and 40 to 95% by weight of a polyimide [polyimide (2)] having a repeating unit represented by the chemical formula 2.

Abstract: A polyimide resin composition comprising 50-95 parts by weight of a polyimide resin represented by the following formula (1): ##STR1## wherein X represents a direct bond, a hydrocarbon group, a carbonyl group, a thio group or so, Y.sub.1 -Y.sub.4 individually represent a hydrogen atom, a lower alkyl group or so and R.sub.1 represents an aliphatic group, an aromatic group or so; and 50-5 parts by weight of a polyetheretherketone, said composition having been subjected to heat treatment at 250.degree.-330.degree. C. and, after the heat-treatment, having crystallization enthalpy of 0-6 cal/g.The heat treatment of the polyimide resin composition can be effected at a low temperature in a short time. The polyimide resin composition has excellent dimensional stability and high-temperature physical properties. Moreover, it has excellent moldability and peeling resistance.

Abstract: The present invention relates to a polyimide based resin composition comprises 1 to 50 parts by weight of polyetherimide for 100 parts by weight a resin composition comprising 50 to 99 parts by weight of polyarylether ketone and 50 to 1 parts by weight of polyimide having specific structural units.The polyimide based resin compositions have excellent fatigue characteristics and creep resistance and are expected widely to apply in field of machine and automobile parts which is required permanence for mechanical strength.

Abstract: Method and apparatus for manufacturing a sheet-prepreg reinforced with fibers wherein a sheet of fibers such as warp or woven fibers such as fabrics is conveyed between a pair of band belts one of which is coated with a film of thermoplastic resin which has been heated higher than its softening point to enhance resin-impregnating efficiency and prevent the impregnated resin from contacting air. Further, when the sheet of fibers or woven fibers is conveyed in this manner, the molten resin is not maintained on the manufacturing line, thereby preventing it from being deteriorated by heat. The apparatus can be thus kept under operation for a long time and the sheet-prepreg reinforced with the fibers can be made much higher in quality and the deterioration of the impregnated resin can be further delayed.

Abstract: Method and apparatus for manufacturing a sheet-prepreg reinforced with fibers wherein a sheet of fibers such as warp or woven fibers such as fabrics is conveyed between a pair of band belts one of which is coated with a film of thermoplastic resin which has been heated higher than its softening point to enhance resin-impregnating efficiency and prevent the impregnated resin from contacting air. Further, when the sheet of fibers or woven fibers is conveyed in this manner, the molten resin is not maintained on the manufacturing line, thereby preventing it from being deteriorated by heat. The apparatus can be thus kept under operation for a long time and the sheet-prepreg reinforced with the fibers can be made much higher in quality and the deterioration of the impregnated resin can be further delayed.

Abstract: This invention relates to a method for preparing a polyimide having good heat-stability and excellent flowability in a molten state.The polymide is prepared by reacting aromatic diamines such as 4,4'-bis(3-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl] ketone and bis [4-(3-aminophenoxy)phenyl] sulfone; tetracarboxylic dianhydrides such as pyromellitic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride and bis(3,4-dicarboxyphenyl) ether dianhydride; and dicarboxylic anhydrides such as glutaric anhydride, 1,2-hexanedicarboxylic anhydride, phthalic anhydride and 3,4-benzophenonedicarboxylic anhydride. The molar ratio of aromatic diamine: tetracarboxylic dianhydride: dicarboxylic anhydride is 1:(0.9 to 1.0):(0.001 to 1.0).The invention also relates to polyimide composite materials which are excellent in mechanical strengths and processability.

Abstract: The invention relates to processes for preparing a polyimide, a polyimide composition prepared by the processes and polyimide composite materials containing the same.