Abstract: A carbon fiber covered on the surface with an aromatic polysulfone resin and then heated at 300-400.degree. C., a heat-resistant resin composition with excellent mechanical strength comprising 5-50% by weight of the carbon fiber and 95-50% by weight of a heat-resistant resin, and an internal combustion engine part, particularly an impeller of centrifugal compressor produced in one step, using the resin composition.

Abstract: A carbon fiber covered on the surface with an aromatic polysulfone resin and then heated at 300.degree.-400.degree. C., a heat-resistant resin composition with excellent mechanical strength comprising 5-50% by weight of the carbon fiber and 95-50% by weight of a heat-resistant resin, and an internal combustion engine part, particularly an impeller of centrifugal compressor produced in one step, using the resin composition.

Abstract: A molding resin composition comprising 99.9 to 50% by weight of polyimide represented by the formula: ##STR1## and 0.1 to 50% by weight of polyether ketone resin and/or polyester resin, and more particularly comprising the polyester resin capable of forming an anisotropical molten phase at a temperature of 420.degree. C. or less, and a polyimide-based molding resin composition which comprises the said resins and other additives such as phenolic resin, fluororesin, graphite, carbon fibers, aromatic polyamide fibers, potassium titanate fibers and a crystallization accelerator, and is excellent in thermal resistance, chemical resistance, mechanical strength and processability.

Abstract: A carbon fiber covered on the surface with an aromatic polysulfone resin and then heated at 300.degree.-400.degree. C., a heat-resistant resin composition with excellent mechanical strength comprising 5-50% by weight of the carbon fiber and 95-50% by weight of a heat-resistant resin, and an internal combustion engine part, particularly an impeller of centrifugal compressor produced in one step, using the resin composition.

Abstract: A molding resin composition comprising 99.9 to 50% by weight of polyimide represented by the formula: ##STR1## and 0.1 to 50% by weight of polyether ketone resin and/or polyester resin, and more particularly comprising the polyester resin capable of forming an anisotropical molten phase at a temperature of 420.degree. C. or less, and a polyimide-based molding resin composition which comprises the said resins and other additives such as phenolic resin, fluororesin, graphite, carbon fibers, aromatic polyamide fibers, potassium titanate fibers and a crystallization accelerator, and is excellent in thermal resistance, chemical resistance, mechanical strength and processability.

Abstract: A molding resin composition comprising 99.9 to 50% by weight of polyimide represented by the formula: ##STR1## and 0.1 to 50% by weight of polyether ketone resin and/or polyester resin, and more particularly comprising the polyester resin capable of forming an anisotropical molten phase at a temperature of 420.degree. C. or less, and a polyimide-based molding resin composition which comprises the said resins and other additives such as phenolic resin, fluororesin, graphite, carbon fibers, aromatic polyamide fibers, potassium titanate fibers and a crystallization accelerator, and is excellent in thermal resistance, chemical resistance, mechanical strength and processability.

Abstract: Resin compositions having excellent mechanical strength, especially at high temperatures are disclosed. The resin compositions comprise 95-60 wt. % of an aromatic polyetherketone having recurring units represented by the following formula: ##STR1## 5-40 wt. % of a polyetherimide having recurring units represented by the following formula: ##STR2## Also disclosed are fiber-reinforced resins, which comprise 75-55 wt. % of one of the above compositions and 25-45 wt. % of carbon fibers obtained by coating starting carbon fibers with an aromatic polysulfone resin and then heating the thus-coated carbon fibers at 300.degree.-400.degree. C., and mechanical components made of desired one of the fiber-reinforced resins which are suitable for use in internal combustion engines or auxiliary equipment.

Abstract: Integrated circuit sockets for use in a burn-in test are disclosed. The IC sockets are produced by injection molding of a specific polyimide having an inherent viscosity of 0.35 to 0.65 dl/g and essentially consisting of recurring units represented by the formula (I): ##STR1## wherein X is a radical selected from the group consisting of a bond, divalent hydrocarbon having from 1 to 10 carbon atoms, etc. and R is a tetravalent radical selected from the group consisting of an aliphatic radical having two or more carbon atoms, cycloaliphatic radical, monoaromatic radical etc.

Abstract: Provided are carbon-fiber-reinforced polyimide resin compositions having excellent mechanical strength. The compositions are formed of (a) 5-50 parts by weight of carbon fibers, which have been obtained by coating starting carbon fibers at surfaces thereof with an aromatic polysulfone resin and then heating the thus-coated carbon fibers at 300.degree.-400.degree. C., and (b) 95-50 parts by weight of a polyimide resin which perferably have recurring units of following formula: ##STR1## wherein X represents a specific divalent radical and R represents a particular tetra-valent radical.