The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 22, 1981
Filed:
Nov. 08, 1979
Yoshikazu Sasaki, Takatsuki, JP;
Hiroshi Inoue, Hirakata, JP;
Ichiro Sasaki, Chiba, JP;
Hiroshi Itatani, Chiba, JP;
Mikito Kashima, Chiba, JP;
UBE Industries, Ltd., Ube, JP;
Abstract
A polyimide solution is prepared by a process wherein a tetracarboxylic acid ingredient containing at least about 80% by mole of 3,3',4,4'-biphenyltetracarboxylic acid or its functional derivative and an aromatic diamine ingredient containing at least about 50% by mole of 4,4'-diaminodiphenyl ether are polymerized at from about 100.degree. to 300.degree. C. in phenol or a halogenated phenolic compound; the amount of the acid and diamine ingredients being approximately equimolar to each other; whereby polymerization of the tetracarboxylic acid ingredient and the aromatic diamine ingredient is effected while being accompanied by imidation. Preferably, the polymerization accompanied by imidation is effected in a manner such that at least a second half of the polymerization is carried out in a closed reaction system. The resulting polyimide solution is suitable for making therefrom shaped articles, such as films, possessing excellent mechanical properties.