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. 15, 1994
Filed:
Sep. 09, 1992
Yoshihiro Kusuki, Chiba, JP;
Toshimune Yoshinaga, Chiba, JP;
Harutoshi Hoshino, Chiba, JP;
Shinji Asanuma, Chiba, JP;
Ube Industries, Ltd., Yamaguchi, JP;
Abstract
A gas separating asymmetric membrane such as a gas separating asymmetric hollow fiber comprises an aromatic polyimide comprising recurring units of the formulae (I) and (II): ##STR1## wherein A.sup.1 is a tetravalent unit having a diphenylhexafluoropropane structure, A.sup.2 is a tetravalent unit having a benzene structure, and A.sup.3 is a divalent aromatic unit which is a unit derived from a sulfur atom-containing diamine such as diaminodibenzothiophene, diaminodiphenylenesulfone, diaminothioxanthene-5,5-dioxide or diaminothioxanthone-5,5-dioxide. The aromatic polyimide contains the recurring unit of the formula (I) in an amount of 40 to 90 molar % and the recurring unit of the formula (II) in an amount of 10 to 40 molar %. Further, a process for the preparation of the gas separating asymmetric hollow fiber membrane is also disclosed.