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:
Dec. 27, 1994
Filed:
May. 17, 1993
Seitz-Filter-Werke GmbH & Co., Bad Kreuznach, DE;
Abstract
A permanently hydrophilic membrane on an aromatic polysulphone basis and a method for its production. Due to their chemical and thermal resistivity and also because they are unobjectionable with respect to their contacting foodstuffs, membranes on an aromatic polysulphone basis represent a preferred filtration material. But since they are hydrophobic, they would have to be hydrophilated before they are used. Known hydrophilation methods were insufficient to maintain the hydrophilic properties of the membranes, especially after repeated sterilization. The new method aims at making the membranes permanently hydrophilic under sterilization conditions. In an aftertreatment step, the membranes on an aromatic polysulphone basis are conducted, before or after drying, through an impregnating bath of polyvinylpyrrolidone, a copolymer of vinylpyrrolidone and one or more hydrophobic monomers and peroxodisulphate, then heated to 70 to 150.degree. C. and cooled down again. The membranes thusly treated remain spontaneously water wettable even after the sterilization.