Abstract: A sliding material and a heat resistant filament which primarily comprises a liquid crystal polyimide, a liquid crystal polyamide or a liquid crystal polyamide-imide copolymer having at least one recurring structural unit selected from the formula (1) and the formula (2) and is excellent in heat resistance, mechanical characteristics and other fundamental properties of polyimides, and relates to significant improvement of heat-resistance by heat-treating the sliding material, the filament and the molded items. The liquid crystal polyamide-imide copolymer which comprises in a polymer molecule 0.05.about.0.95 mole ratio of the recurring structural units of the formula (1) and 0.95.about.0.

Abstract: A is a polyimide based resin molding composition comprising 100 parts by weight of crystalline polyimide having recurring structural units of the formula (1): ##STR1## and 1.about.50 parts by weight of crystallization accelerators selected from bisimide compounds of specific structure, a mixture of bisimide compounds, and imide based oligomer. The composition remarkably accelerates the crystallization velocity of polyimide of the formula (1), crystallization can be completed within a greatly reduced cooling time after melt processing, and the crystallized polyimide resin has excellent properties.

Abstract: The invention provides a novel preparation process of a polycondensation type polymer, an excellent polymer which is represented by lactic acid and the preparation process of the polymer, a polycondensation agent used for the preparation process, and an intermediate. Specifically, the invention provides a preparation process of the polycondensation type polymer, for example, polyamide, polyimide, polythioester and polyester, comprising bonding a carboxyl group comprising compound with an active hydrogen group comprising compound in the presence of haloiminium salt. The invention provides excellent polylactic acid having a controlled D/L-isomer ratio in the repeating structural units and preparation process of polylactic acid, and further provides a haloiminium salt compound used for the preparation process and an intermediate compound of acid chloride.

Abstract: Novel thermoset polyimide and composite materials comprising the thermoset polyimides and a fibrous reinforcement are prepared according to this invention. The thermoset polyimides are obtained by heat-treating a linear polyamic acid or a linear polyimide prepared by using 4,4'-bis(3-aminophenoxy)biphenyl and pyromellitic dianhydride as essential monomers or by adding 4,4'-diaminodiphenyl ether or 3,3',4,4'-biphenyltetracarboxylic dianhydride to the essential monomers and by end-capping the molecular chain end with an aromatic dicarboxylic anhydride having a carbon-carbon triple bond. The thermoset polyimides have essential excellent properties of thermoplastic polyimide and additionally has enhanced heat resistance and improved mechanical properties. The thermoset polyimide can be used to provide various kinds of composite materials for aircraft matrices, electric and electronic appliances and others.

Abstract: Disclosed is an aromatic diamine compound represented by the formula (I) ##STR1## wherein R is H or CH.sub.3. Also disclosed is a bismaleimide compound represented by the formula (IV) ##STR2## wherein R is H or CH.sub.3, A resin forming composition comprising these compounds is also disclosed. The compounds are useful as raw materials for resins, and the resin forming composition and the resin can provide excellent heat resistance and impact resistance and low hygroscopicity.

Abstract: This invention relates to a novel polyimide or polyimide copolymer having excellent heat resistance and greatly improved processability, and has a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the polyimide or polyimide copolymer and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition.The polyimide comprise a requisite structural unit having one or more recurring structural units of the formula: ##STR1## wherein L is an oxygen atom, carbonyl, isopropylidene or hexafluoroisopropylidene, and X is ##STR2## and Ar is a tetravalent radical having 6 to 27 carbon atoms and being selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed polyaromatic radical having aromatic radicals connected to each other with a direct bond or a bridge member.

Abstract: In one aspect, the present invention relates to polyimides having excellent thermal resistance and process for preparing the same comprising carrying out condensation of 4,4'-bis(3-aminophenoxy)biphenyl with pyromellitic dianhydride in the presence of a different diamine compound and optionally with a different tetracarboxylic acid dianhydride.In a second aspect, the present invention relates to a heat resistant resin composition consisting essentially of an aromatic polyetherimide and a defined polyimide.In a third aspect, the present invention relates to a polyimide resin composition comprised on a defined polyimide and a separate high-temperature engineering polymer.In a fourth aspect, the present invention relates to a resin composition comprised of a defined polyimide and an aromatic polyamideimide.

Abstract: A fatigue-resistant polyimide resin composition comprising 100 parts by weight of polyimide having from 0.5 (exclusive) to 1.0 (inclusive) mole ratio of recurring structural units represented by the formula (1) and from 0 (inclusive) to 0.5 (exclusive) mole ratio of recurring structural units represented by the formula (2): ##STR1## wherein X is ##STR2## in the formulas (1) and (2), and having an inherent viscosity of 0.45 dl/g or more; and 5.about.65 parts by weight of a carbon fiber, glass fiber, aromatic polyamide fiber and/or potassium titanate fiber, and an injection molded article having a high fatigue resistance.

Abstract: A polyimide resin composition substantially comprising 1 99.9.about.50 parts by weight of polyimide having recurring structural units of the formula ##STR1## and 2 0.1.about.50 parts by weight of a polyimide which improved melt flowability and is prepared by using 1,3-bis(3-aminophenoxy)benzene or 6,6'-bis(3-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane as essential diamine component, or polyether pyridine having recurring structural units of the formula: ##STR2## is disclosed. Further, a polyimide based resin composition comprising the polyimide resin composition or a polyimide copolymer obtained by using the above diamines and a fibrous reinforcement is disclosed. These compositions have remarkably good processability, excellent heat stability and repeated fatigue characteristics.

Abstract: Disclosed is an aromatic diamine compound represented by the formula (I) ##STR1## wherein R is H or CH.sub.3. Also disclosed is a bismaleimide compound represented by the formula (IV) ##STR2## wherein R is H or CH.sub.3, A resin forming composition comprising these compounds is also disclosed. The compounds are useful as raw materials for resins, and the resin forming composition and the resin can provide excellent heat resistance and impact resistance and low hygroscopicity.

Abstract: The present invention relates to an amorphous polyimide or a polyimide copolymer having a requisite structural unit consisting of one or more recurring structural units represented by the formula (1): ##STR1## wherein X is a direct bond, oxygen atom or sulfur atom, and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are individually a hydrogen atom or methyl, and Ar is a tetravalent radical having 6 to 27 carbon atoms and being selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed polyaromatic radical having aromatic radicals connected to each other with a direct bond or a bridge member.Polyimide and the polyimide copolymer of the invention has excellent heat resistance, is outstanding in melt-flow stability, has greatly improved processability, and can be applied to structural materials, and electric- electronic appliances.

Abstract: This invention relates to a novel thermoplastic and amorphous polyimide which is readily soluble in organic solvent, a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the thermoplastic polyimide and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition, a polyimide-based composite obtained by molding the above soluble and thermoplastic polyimide in combination with a fibrous reinforcement, and a fibrous reinforcement having a surface modified with the above polyimide.

Abstract: This invention relates to a novel fluorine-containing polyimide or polyimide copolymer being colorless and having transparency and very low dielectric characteristics, and has a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the polyimide or polyimide copolymer and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition.

Abstract: In one aspect, the present invention relates to polyimides having excellent thermal resistance and process for preparing the same comprising carrying out condensation of 4,4'-bis(3-aminophenoxy)biphenyl with pyromellitic dianhydride in the presence of a different diamine compound and optionally with a different tetracarboxylic acid dianhydride.In a second aspect, the present invention relates to a heat resistant resin composition consisting essentially of an aromatic polyetherimide and a defined polyimide.In a third aspect, the present invention relates to a polyimide resin composition comprised on a defined polyimide and a separate high-temperature engineering polymer.In a fourth aspect, the present invention relates to a resin composition comprised of a defined polyimide and an aromatic polyamideimide.

Abstract: In one aspect, the present invention relates to polyimides having excellent thermal resistance and process for preparing the same comprising carrying out condensation of 4,4'-bis(3-aminophenoxy)biphenyl with pyromellitic dianhydride in the presence of a different diamine compound and optionally with a different tetracarboxylic acid dianhydride.In a second aspect, the present invention relates to a heat resistant resin composition consisting essentially of an aromatic polyetherimide and a defined polyimide.In a third aspect, the present invention relates to a polyimide resin composition comprised on a defined polyimide and a separate high-temperature engineering polymer.In a fourth aspect, the present invention relates to a resin composition comprised of a defined polyimide and an aromatic polyamideimide.

Abstract: Polyimide filaments and polyimide films having great strength, high elastic modulus and high crystallinity and comprising a novel polyimide which can be melt-processed without impairing high crystallinity and which essentially consists of recurring structural units represented by the formula (I): ##STR1## more than 85 mol % the polyimide consists of recurring structural units of the formula (II): ##STR2## and from 0.5 to 15 mol % of the polyimide consists of recurring structural units represented by the formula (III), the formula (II) exclusive, the formula (IV) and/or the formula (V).

Abstract: Amorphous polyimide powder which has recurring structural units of the formula (I): ##STR1## as a fundamental skeleton, is blocked at the polymer chain end with dicarboxylic anhydride represented by the formula (II) ##STR2## wherein Z is a divalent radical having from 6 to 27 carbon atoms and selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed aromatic radical connected to each other with a direct bond or a bridge member, and essentially has no reactive radical at the polymer chain end, preparation process of the amorphous polyimide powder, heat-resistant adhesive comprising the polyimide, and bonding method using the adhesive.

Abstract: Disclosed is an aromatic diamine compound represented by the formula (I) ##STR1## wherein R is H or CH.sub.3. Also disclosed is a bismaleimide compound represented by the formula (IV) ##STR2## wherein R is H or CH.sub.3, A resin forming composition comprising these compounds is also disclosed. The compounds are useful as raw materials for resins, and the resin forming composition and the resin can provide excellent heat resistance and impact resistance and low hygroscopicity.

Abstract: A heat-resistant and thermoplastic polyimide which has low dielectric characteristics and recurring structural units of the following formula: ##STR1## wherein R is a tetravalent radical having from 2 to 27 carbon atoms and selected from the group consisting of an aliphatic radical, alicyclic radical, monoaromatic radical, condensed polyaromatic radical and noncondensed aromatic radical connected each other with a direct bond or a bridge member; aromatic diamines which are useful for the raw material monomers of the polyimide and have following formulas: ##STR2## and a process for preparing the polyimide of the above formula by reacting these aromatic diamines with a tetracarboxylic dianhydride in the presence of an aromatic dicarboxylic anhydride or aromatic monoamine, and successively thermally or chemically imidizing the resultant polyamic acid; are disclosed.

Abstract: A polyimide-based heat-resistant adhesive having excellent peel strength and heat resistance comprising polyimide composed of 10 to 99% by mole of structural units having the formula (1) and 1 to 90% by mole of structural units having the formula (2) or comprising polyamic acid precursor which corresponds to the polyimide.