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. 10, 2007
Filed:
May. 23, 2001
Friedbert Wechs, Wörth, DE;
Friedbert Wechs, Wörth, DE;
Membrana GmbH, Wuppertal, DE;
Abstract
The invention relates to a method for producing a hydrolytically stable polyamide membrane having an open-pored, microporous and sponge-like support-layer structure, using a process involving thermally induced liquid-liquid phase separation. A solution of an aliphatic polyamide in a solvent system, comprising preferably a solvent and a non-solvent for the polyamide, is extruded to form a shaped object. After leaving the die, the shaped object is cooled by means of a cooling medium until phase separation occurs and the polymer-rich phase solidifies to form the membrane structure. The solution of the polyamide in the solvent system contains an antioxidant agent as a stabiliser for the polyamide which, together with the solvent system, is selected in a way that the antioxidant agent is essentially insoluble in the solvent system at the phase separation temperature. The invention also relates to a polyamide membrane with improved hydrolytic stability, characterised in that it contains an antioxidant agent as a stabiliser for improving hydrolytic stability.