Polyimides and processes for preparing the same
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsIchiro Kaneko, Atushi Sugitani, Masahiro Yuyama, Kiyoshi Motomi
Life of this patent
Estimating the term…
Abstract
Polyimides comprising recurring units of the following general formula (1) ##STR1## wherein Ar.sub.1 represents a tetravalent aromatic group and each Ar.sub.2 represents a divalent aromatic group. Polyimide copolymers and preparations of the polyimides and the polyimide copolymers are also described.
Claims20
A process for preparing a polyimide having main recurring units of the following formula (1) ##STR11## wherein Ar.sub.1 represents a tetravalent aromatic group and each Ar.sub.2 represents a divalent aromatic group, which comprises polymerizing at least one aromatic tetracarboxylic acid dianhydride of the following formula (4) ##STR12## wherein Ar.sub.1 is defined above, and at least one aromatic diamine of the following formula (5) ##STR13## wherein Ar.sub.2 is defined above, to obtain a polyamido acid having recurring units of the following formula (6) ##STR14## wherein Ar.sub.1 and Ar.sub.2 have the same meanings as defined above, and condensing a --COHN-- group joined to a benzene ring and an OH group at the ortho position through dehydration to thereby form a benzoxazole ring, and forming an imido ring to obtain the polyimide having main recurring units of formula (1).
A process for preparing a polyimide copolymer, which comprises polymerizing an aromatic diamine mixture comprising 4,4'-bis(4-aminobenzamido)-3,3'-dihydroxybiphenyl and 4,4'-diamidodiphenyl ether, and a tetracarboxylic acid dianhydride to obtain a polyamido acid copolymer, and condensing a --COHN-- group joined to a benzene ring and an OH group at the ortho position through dehydration to thereby form a benzoxazole ring, and forming an imido ring to obtain the polyimide copolymer.
Dependencies are inferred from the claim text.