Appeal No. 95-4865
Application No. 08/240,505
membranes in the plural membrane filter element of Ashelin, as
modified by Kawai, would satisfy the claimed limitation of a
“continuous support web on both faces” of the membrane.
We cannot agree with the examiner that the combined
teachings of Ashelin and Kawai either teach or suggest the
subject matter defined by independent claim 1. Specifically,
there is absolutely nothing in Kawai which would teach or suggest
“a nonwoven paper of thermally bonded PTFE fibers” as the
examiner apparently believes. As the examiner recognizes, Kawai
teaches a method of making a porous PTFE membrane having either a
hollow fiber construction or a sheet-like construction made from
“a poly-resin dispersion and a fiber or film forming (referred to
[as] film forming hereunder) polymer” (see column 1, lines 54-2
58). Kawai thereafter states that the method includes the steps
of:
forming a film having a hollow construction or a sheet-
like construction from a mixture of a polytetrafluoro-
ethylene resin dispersion and a film-forming polymer;3
heat-treating the film at a temperature not lower than
2It thus appears that Kawai utilizes the terminology “fiber
forming” and “film forming” synonymously.
3This dispersion is subsequently stated to contain “PTFE
resin particles of a particular size . . .” (see column 3, lines
60-61; emphasis ours).
3
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