Asymmetrical ultrafiltration membrane based on cellulose hydrate

US4234528A · kind A · utility

Assignee

• Sartorius AG · DE

Inventors

• Dietmar Nussbaumer · Göttingen, DE
• Horst Perl · Göttingen, DE

Key dates

• Filing date: Apr 10, 1979
• Grant date: Nov 18, 1980
• Expiry date: Apr 10, 1999

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D71/16
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

An asymmetrical ultrafiltration membrane based on cellulose hydrate which may be dried without destructive shrinkage and which has been saponified without reduction in flow-through or separation performance is prepared by adding hydrophobic synthetic silicic acid to a casting solution based on cellulose triacetate optionally partially substituted by cellulose diacetate, and then casting the cellulose acetate membrane and saponifying to the cellulose hydrate form.