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:
May. 03, 1994
Filed:
Nov. 26, 1991
Toshikazu Hamamoto, Osaka, JP;
Hiroshi Inoue, Osaka, JP;
Yoshiyuki Miwa, Osaka, JP;
Tetsuji Hirano, Osaka, JP;
Katsuo Imatani, Yamaguchi, JP;
Kenji Matsubara, Yamaguchi, JP;
Takashi Kohno, Yamaguchi, JP;
Ube Industries, Ltd., Yamaguchi, JP;
Abstract
A process for the preparation of an aromatic polyimide film includes the steps of casting a polyamide acid solution containing an imidization agent on a support in the form of a film, heating the filmy cast solution on the support at a temperature of 80.degree. to 200.degree. C. to obtain a self-supportable film; peeling the self-supportable film from the support; and further heating the film at a temperature of not lower than 300.degree. C. The polyamide acid solution includes a polyamide acid obtained by polymerization reaction of 3,4,3',4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine in a mixture of a polar organic solvent and a small amount of an imidization agent selected from imidazole, a substituted imidazole, benzimidazole, a substituted benzimidazole, isoquinoline, and a substituted pyridine.