Appeal No. 95-4970
Application No. 08/012,,872
1. A process for preparing a microporous membrane from a
poly(phenylene sulfide) polymer comprising the steps of:
A. forming a mixture comprising:
(i) at least one poly(phenylene sulfide) polymer,
(ii) at least one amorphous polymer which is substantially
stable at elevated temperatures, which possesses a glass
transition temperature of at least about -100EC, and wherein said
amorphous polymer is at least partially immiscible in said
poly(phenylene sulfide) polymer at ambient conditions; and
(iii) optionally a plasticizer comprising at least one
organic compound capable of dissolving at least about 10 weight
percent of said poly(phenylene sulfide) polymer at the extrusion
or casting temperature;
B. heating the mixture to a temperature at which said mixture
becomes a fluid;
C. extruding or casting said fluid under conditions such that a
membrane is formed;
D. subjecting said membrane to controlled cooling or
coagulation by passing said membrane through at least one
zone under conditions such that said membrane solidifies;
E. leaching said membrane by passing said membrane through at
least one zone under conditions such that at least a portion
of said optional plasticizer for said poly(phenylene sulfide)
polymer, at least a portion of said amorphous polymer, or a
combination thereof, is removed from said membrane; and
F. producing a final microporous membrane.
The examiner relies upon the following references as
evidence of obviousness:
Beck 5,043,112 Aug. 27, 1991
Damrow et al. (Damrow) 5,205,968 Apr. 27, 1993
-2-
Page: Previous 1 2 3 4 5 Next
Last modified: November 3, 2007