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:
Sep. 30, 2008
Filed:
Jan. 08, 2003
Erich Kessler, Höchst i. Odw., DE;
Thomas Batzilla, Miltenberg, DE;
Friedbert Wechs, Wörth, DE;
Frank Wiese, Wuppertal, DE;
Erich Kessler, Höchst i. Odw., DE;
Thomas Batzilla, Miltenberg, 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, using a thermally induced liquid-liquid phase separation process. A solution of at least one polyolefin is extruded to form a shaped object. The solvent used is one for which the demixing temperature of a solution of 25% by weight of the polyolefin in this solvent is 10 to 70° C. above the solidification temperature. After leaving the die, the shaped object is cooled using a liquid cooling medium that does not dissolve the polymer up to the die temperature, until the phase separation and solidification of the high-polymer-content phase take place. The integrally asymmetrical membrane producible in this manner has a porosity of greater than 30% to 75% by volume, a sponge-like, open-pored, microporous support layer without macrovoids and with on average isotropic pores, and on at least one of its surfaces a separation layer with pores <100 nm, if any. The membrane is preferably used for gas separation or gas transfer processes, in particular for oxygenation of blood.