Patent · US Expired

Method for producing an integrally asymmetrical polyolefin membrane

US6375876B1 · kind B1 · utility

17Cited by

7References

23Claims

0Family size

Assignee

Membrana GmbH · DE

Inventors

Erich Kessler · Kelsterbach, DE
Thomas Batzilla · Miltenberg, DE
Friedbert Wechs · Bad Mergentheim, DE
Frank Wiese · Huntsville, US

Key dates

Filing date	Sep 4, 2001
Grant date	Apr 23, 2002
Priority date	—
Expiry date	Sep 4, 2021

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB01D2325/026
WIPO fieldChemical engineering
WIPO sectorChemistry

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.