Abstract: Provided is a solvent-soluble polyimide copolymer which satisfies storage stability and heat resistance at high levels and has excellent utility. The polyimide copolymer is obtained by copolymerizing (A) 3,3?,4,4?-biphenyltetracarboxylic dianhydride with (B) diamine(s) and/or diisocyanate(s) and has no glass transition temperature observed at lower than 500° C. The component (B) is preferably at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): (wherein, X represents an amino group or an isocyanate group; R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R8 is not a hydrogen atom).

Abstract: Provided are: an oligomer of polyimide copolymer which is an intermediate of a polyimide copolymer having excellent utility and satisfying solvent solubility, storage stability and heat resistance at high levels; a polyimide copolymer obtained therefrom; and their production methods. The oligomer of polyimide copolymer and the polyimide copolymer are obtained by copolymerizing (A) 3,3?,4,4?-biphenyltetracarboxylic dianhydride and/or 3,3?,4,4?-diphenylsulfonetetracarboxylic dianhydride with (B) at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): (wherein, X represents an amino group or an isocyanate group; R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R8 is not a hydrogen atom).

Abstract: Provided are: a transparent polyimide copolymer which satisfies solvent solubility, storage stability, heat resistance, mechanical strength and thermal yellowing resistance at high levels and has excellent utility; a polyimide resin composition; a molded article; and a production method of the copolymer. The transparent polyimide copolymer is obtained by copolymerizing: (A) 4,4?-oxydiphthalic dianhydride and/or 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; and (B) at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): (wherein, X represents an amino group or an isocyanate group; R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R8 is not a hydrogen atom).

Abstract: Provided are: a transparent polyimide copolymer which satisfies solvent solubility, storage stability, heat resistance, mechanical strength and thermal yellowing resistance at high levels and has excellent utility; a polyimide resin composition; a molded article; and a production method of the copolymer. The transparent polyimide copolymer is obtained by copolymerizing: (A) 4,4?-oxydiphthalic dianhydride and/or 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; and (B) at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): (wherein, X represents an amino group or an isocyanate group; R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R8 is not a hydrogen atom).

Abstract: The present invention provides: a polyimide copolymer which satisfies solvent solubility, storage stability and heat resistance at high levels and has excellent utility; and a method of producing the same. The polyimide copolymer is obtained by copolymerizing an oligomer of polyimide copolymer, which is obtained by copolymerizing (A) a pyromellitic dianhydride and (B) at least one diamine and/or diisocyanate represented by the following Formula (1) or (2): (wherein, X represents an amino group or an isocyanate group; R1 to R4 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R4 is not a hydrogen atom), with (C) second acid dianhydride different from the (A).

Abstract: Provided are: a transparent polyimide copolymer which satisfies solvent solubility, storage stability, heat resistance, mechanical strength and thermal yellowing resistance at high levels and has excellent utility; a polyimide resin composition; a molded article; and a production method of the copolymer. The transparent polyimide copolymer is obtained by copolymerizing: (A) 4,4?-oxydiphthalic dianhydride and/or 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; and (B) at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): (wherein, X represents an amino group or an isocyanate group; R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R8 is not a hydrogen atom).

Abstract: Provided is a solvent-soluble polyimide copolymer which satisfies storage stability and heat resistance at high levels and has excellent utility. The polyimide copolymer is obtained by copolymerizing (A) 3,3?,4,4?-biphenyltetracarboxylic dianhydride with (B) diamine(s) and/or diisocyanate(s) and has no glass transition temperature observed at lower than 500° C. The component (B) is preferably at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): (wherein, X represents an amino group or an isocyanate group; R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R8 is not a hydrogen atom).

Abstract: Provided are: an oligomer of polyimide copolymer which is an intermediate of a polyimide copolymer having excellent utility and satisfying solvent solubility, storage stability and heat resistance at high levels; a polyimide copolymer obtained therefrom; and their production methods. The oligomer of polyimide copolymer and the polyimide copolymer are obtained by copolymerizing (A) 3,3?,4,4?-biphenyltetracarboxylic dianhydride and/or 3,3?,4,4?-diphenylsulfonetetracarboxylic dianhydride with (B) at least one diamine and/or diisocyanate represented by the following Formulae (1) to (3): (wherein, X represents an amino group or an isocyanate group; R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R8 is not a hydrogen atom).

Abstract: The present invention provides: a polyimide copolymer which satisfies solvent solubility, storage stability and heat resistance at high levels and has excellent utility; and a method of producing the same. The polyimide copolymer is obtained by copolymerizing an oligomer of polyimide copolymer, which is obtained by copolymerizing (A) a pyromellitic dianhydride and (B) at least one diamine and/or diisocyanate represented by the following Formula (1) or (2): (wherein, X represents an amino group or an isocyanate group; R1 to R4 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms; and at least one of the R1 to R4 is not a hydrogen atom), with (C) second acid dianhydride different from the (A).