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. 23, 1989
Filed:
Apr. 27, 1987
Katsuya Yamada, Osaka, JP;
Koichi Okita, Osaka, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
A gas-selectively permeable membrane and a method of forming said membrane are described. This membrane is an asymmetrical pore diameter structure film made of a polyetherimide having the recurring unit represented by formula (A) or a mixture of said polyetherimide and at least one polymer having the recurring unit represented by formula (B), wherein the means pore diameter of a dense layer of the asymmetrical pore diameter structure film is 0.5 micron or less and the means thickness of the dense layer is 10 microns or less: ##STR1## wherein all the symbols are defined in the specification. This membrane is superior in heat resistance and is suitable for use in the isolation of argon from air, for the concentration of oxygen, for the concentration of hydrogen in twon gas, and so forth.