Transparent polyimide copolymer, polyimide resin composition and molded article, and production method of said copolymer
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; R 1 to R 8 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 R 1 to R 8 is not a hydrogen atom).
1. A transparent polyimide copolymer obtained by copolymerizing:
(A) 4,4′-oxydiphthalic dianhydride; and
(B) at least one diamine and/or diisocyanate represented by the following Formulae (1) or (2):
(wherein, X represents an amino group or an isocyanate group; R 1 to R 4 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 said R 1 to R 4 is not a hydrogen atom).
2. The transparent polyimide copolymer according to claim 1 , having no amino group terminal.
3. The transparent polyimide copolymer according to claim 1 , wherein two of said R 1 to R 4 in said Formula (1) or (2) of said (B) are ethyl groups and the other two are a methyl group and a hydrogen atom.
4. The transparent polyimide copolymer according to claim 1 , wherein (C) second acid dianhydride and/or (D) second diamine and/or diisocyanate is/are further copolymerized.
5. A polyimide resin composition comprising the transparent polyimide copolymer according to claim 1 .
6. A molded article obtained by molding the polyimide resin composition according to claim 5 .
7. A method of producing a transparent polyimide copolymer, said method comprising:
the oligomer production step of producing an oligomer of transparent polyimide copolymer by copolymerizing (A) 4,4′-oxydiphthalic dianhydride with (B) at least one diamine and/or diisocyanate represented by the following Formulae (1) to (2):
(wherein, X represents an amino group or an isocyanate group; R 1 to R 4 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 said R 1 to R 4 is not a hydrogen atom); and
the polyimide copolymer production step of producing a transparent polyimide copolymer by copolymerizing said oligomer of transparent polyimide copolymer produced in said oligomer production step with (C) second acid dianhydride and (D) second diamine and/or diisocyanate.
8. The method of producing an oligomer of transparent polyimide copolymer according to claim 7 , wherein said transparent polyimide copolymer oligomer produced in said oligomer production step has an acid terminal.
9. The method of producing a transparent polyimide copolymer according to claim 7 , wherein two of said R 1 to R 4 in said Formula (1) or (2) of said (B) are ethyl groups and the other two are a methyl group and a hydrogen atom.