TITLE: HYDROPHILIC POLYMERIC MEMBRANES, PROCESS FOR THEIR PREPARATION, THEIR
USE AS ULTRAFILTRATION MEMBRANES, AND PRECURSOR MEMBRANES ADAPTED TO BE
CONVERTED THERETO
European Patent EP0012557
 B1

ABSTRACT:
Abstract of EP0012557
The invention provides a hydrophilic microporous polymeric membrane
comprising an intimate blend of a vinylidene fluoride polymer and from
20 to 75% by weight, based on total polymer, of a vinyl alcohol
polymer. This membrane may be prepared by casting a thin film of a
casting solution comprising a solution of a vinylidene fluoride polymer
and from 35 to 85 weight percent, based on total polymer, of a vinyl
acetate polymer in a solvent on a support base, partially evaporating
the solvent from the cast film, contacting the partially evaporated
cast film with a leaching liquid to render the film microporous, and
hydrolyzing the vinyl acetate polymer in the leached membrane to
convert the acetate groups to hydroxyl groups and provide a membrane
having good mechanical strength and hydrophilic properties. The
membrane is useful as an ultrafiitration membrane, particularly in the
treatment of oil-in-water emulsions or whey. By first forming a film of
the vinylidene fluoride polymer and the vinyl acetate polymer, the
difficulty previously associated with incorporating a hydrophilic
polymer, such as a vinyl alcohol polymer, in a hydrophobic polymer,
such as a vinylidene fluoride polymer is obviated.

INVENTORS:
Jakabhazy, Stephen Z.
Zeman, Leos J.

APPLICATION NUMBER: EP19790302787
PUBLICATION DATE: 02/16/1983
FILING DATE: 12/04/1979

ASSIGNEE: ABCOR, INC.
INTERNATIONAL CLASSES: B01D67/00; B01D71/34; B01D71/38; B01D67/00; B01D71/00; (IPC1-7):
B01D13/04; C08J5/22; C08L27/16; C08L29/04
EUROPEAN CLASSES: B01D67/00R18; B01D71/34; B01D71/38