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:
Apr. 23, 2002
Filed:
Sep. 04, 2001
Erich Kessler, Höchst i. Odw., DE;
Thomas Batzilla, Bürgstadt, DE;
Friedbert Wechs, Wörth, DE;
Frank Wiese, Wuppertal, DE;
Membrana GmbH, Wuppertal, DE;
Abstract
Process for producing an integrally asymmetrical hydrophobic polyolefinic membrane with a sponge-like, open-pored, microporous support structure and a separation layer with a denser structure compared to the support structure, via a thermally induced liquid-liquid phase separation process. A solution of at least one polyolefin in a solvent system consisting of a compound A and a compound B is extruded to form a shaped object. Compound A is a weak solvent and compound B a non-solvent for the polymer. After leaving the die, the shaped object is cooled using a solid or liquid cooling medium that does not dissolve or react chemically with the polymer at temperatures up to the die temperature, until the phase separation and solidification of the high-polymer-content phase take place.