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. 06, 1997
Filed:
Jun. 07, 1995
Kazuhiro Meguro, Ryugasaki, JP;
Toshiya Mizuno, Tsuchiura, JP;
Yoshikiti Teramoto, Ami-machi, JP;
Hiroshi Sato, Tamari-mura, JP;
Kureha Chemical Industry Co., Ltd., Tokyo, JP;
Abstract
A method of making a polyvinylidene fluoride porous membrane having an asymmetric structure, excellent mechanical strength and a narrow range of pore diameter distribution comprises: blending (i) 100 parts by weight of a vinylidene fluoride resin having an inherent viscosity, measured in dimethylformamide at a concentration of 0.4 g/dl and a temperature of 30.degree. C., of 1.4 to 15.0, (ii) 30 to 250 parts by weight of an aliphatic polyester plasticizer and, optionally and preferably, (iii) 1 to 50 parts by weight of a good solvent for vinylidene fluoride resin, to form a composition; extruding the so-formed composition to form a molten film; cooling one surface of the molten film by contact with a chill roll having a temperature of not more than 150.degree. C. and air-cooling the other surface to make a solid film; and extracting the plasticizer from the solid film.