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:
Aug. 14, 1990
Filed:
Jun. 28, 1989
Yasuharu Yamada, Kitakyushu, JP;
Nobuyuki Furukawa, Kitakyushu, JP;
Masaya Furukawa, Kitakyushu, JP;
Nippon Steel Chemical Co., Ltd., Tokyo, JP;
Abstract
Polyimide-based separation membranes of this invention are made from polyimides having repeating units of the general formulas (A) and (B) ##STR1## wherein Ar.sub.1 and Ar.sub.3 are tetravalent aromatic radicals containing at least one aromatic ring, Ar.sub.2 is a divalent aromatic radical containing at least one aromatic ring, R.sub.1 and R.sub.2 are organic radicals, R.sub.3 to R.sub.6 are monovalent hydrocarbon radicals, and n is an integer from 1 to 50 at a mole ratio (A)/(B) of 5/95 to 95/5, have high gas permeation coefficients, high mechanical strength, and excellent heat resistance, and are useful for separation and concentration of mixed gases.