POLYAMIC ACID COPOLYMER, POLYIMIDE COPOLYMER, POLYIMIDE FILM, AND PREPARATION OF THE SAME

Japanese Patent JP3048702

B2

PURPOSE: To provide a polyimide copolymer improved in elasticity, low expansion and flexibility by adding a tetracarboxylic acid dianhydride to a linear diamine, followed by the addition thereto of a specific tetracarboxylic acid dianhydride and a flexible diamine.
CONSTITUTION: n equivalents of at least one tetracarboxylic acid dianhydride selected from among pyromellitic acid dianhydride and its derivs. is added to 2n equivalents of a linear diamine, followed by the addition thereof of (n+1) equivalents of at least one tetracarboxylic acid dianhydride selected from among those of formulae I to III and subsequent addition thereto of 1 equivalent of a flexible diamine to obtain a polyamic acid copolymer having structural units of formula IV [R2 and R4 are a linear diamine residue; R6 is a flexible diamine residue; R3 is a pyromellitic dianhydride (deriv.) residue; R1 and R5 are each an arbitrary residue selected from among those of formulae V to VII; and n is 3 or more]. This copolymer is dehydrated for ring closure to obtain a polyimide copolymer having an average mol.wt. of 10,000 to 100,000.

Suguru Ito
Yoshifumi Okada
Hitoshi Nojiri

JP26279291A

June 05, 2000

September 13, 1991

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Kanegafuchi Chemical Industry Co., Ltd.

C08G73/10; C08J5/18; C08L79/08; (IPC1-7): C08G73/10; C08J5/18

JP59108029A
JP60210894A
JP63166287A
JP63254131A
JP6416832A
JP1282218A
JP559173A
JP551453A
JP4335028A
JP4320422A
JP63314242A

Kenji Itami

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