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. 14, 1978
Filed:
Apr. 22, 1976
Kazuhisa Yamauchi, Kurashiki, JA;
Koichi Takakura, Okayama, JA;
Syuji Kawai, Kurashiki, JA;
Akio Ohmori, Kurashiki, JA;
Kuraray Co., Ltd., Kurashiki, JA;
Abstract
A polyvinyl alcohol semi-permeable membrane is prepared which has micropores with an average diameter of 0.02 to 2 microns as defined by the interpore partition walls having thicknesses in the range of 50 to 5000 A and which is characterized by substantial cross-sectional uniformity. The membrane is prepared by extruding a PVA composition containing PAG with a molecular weight of 400 to 4,000 and a carbon-to-oxygen ratio of not more than 3 in a proportion of 2 to 200 parts by weight per 100 parts of PVA into a coagulation bath. In another embodiment of the invention, the membrane is formed from a PVA composition wherein the PAG has a molecular weight of 600 to 3,000 and a C/O ratio of not more than 3, the proportion of the PAG being 15 to 150 parts by weight per 100 parts of PVA and wherein the composition satisfies the relation: 0.65 .ltoreq. CBR (critical blending ratio) .ltoreq. 1.0. The membrane is useful in ultrafiltration, dialytic and osmotic separation applications.