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:
Feb. 06, 1990
Filed:
May. 26, 1988
Hiroshi Inoue, Hirakata, JP;
Tadao Muramatsu, Hirakata, JP;
Yasuji Narahara, Hirakata, JP;
Tetsuji Hirano, Hirakata, JP;
UBE Industries, Ltd., Ube, JP;
Abstract
A process for the preparation of an aromatic polyimide film having a surface provided with extremely small sized protrusions having an average diameter of 40 to 2,000 angstroms, the number of protrusions being in the range of 1.times.10.sup.4 to 1.times.10.sup.9 /mm.sup.2 is disclosed. The process comprises the steps of coating a coating composition (aromatic polyamic acid solution containing inorganic particles having an average diameter of not larger than 1,000 angstroms) on at least one surface of an aromatic polyimide gel film containing a volatile material in an amount of 10 to 90 wt. % (aromatic polyimide gel film has been obtained by ring closure and imidation of an aromatic polyamic acid in an organic polar oslvent containing a dehydrating agent and a catalyst at a temperature of not higher than 200.degree. C.); drying the obtained film composite at a temperature of 50.degree. to 200.degree. C.; and subjecting the film composite to a heat treatment including heating at a temperature of not lower than 300.degree. C.