Appeal No. 2006-0791 Ex parte Gore Enterp. Holdings, Inc.
Bamdad Bahar, A.R. Hobson & J.A. Kolde, "Ultra-thin integral composite
membrane", U.S. 6,254,978 B1 (granted 3 July 2001) [978 patent].
[2] The appellant [Gore] in part cites (App. Br. at 3-4) the following text from the
disclosure (4:10-34 & 47-611) to describe the invention:
An ultra-thin composite membrane is provided and includes a base mat-
erial of microporous membrane with a thickness less than 1 mil (0.025 mm)
having a microstructure of micropores and perfluoro ion exchange resin that
substantially impregnates the microporous membrane so as to occlude the micro-
pores. The ultra-thin composite membrane may be employed in many different
types of applications including for example, chemical separation, electrolysis in
fuel cells and batteries, pervaporation, gas separation, dialysis separation, indus-
trial electrochemistry such as chlor-alkali, and other electrochemical devices,
catalysis as a super acid catalyst and use as a medium of in enzyme immobiliza-
tion.
The ultra-thin composite membrane is mechanically strong and is substan-
tially and uniformly pore occlusive so that it is particularly useful as an ion ex-
change material. Ultra-thin is hereby defined as 1 mil (0.025 mm) or less. Uni-
form is hereby defined as continuous impregnation with the ion exchange material
so that no pin holes or other discontinuities exist within the composite structure.
In addition, pore occlusive is hereby defined as pores being substantially impreg-
nated (i.e., at least 90%) with the perfluoro ion exchange material rendering the
final material air impermeable with a Gurley number of infinity.
* * * * *
* * * A most preferred material is expanded porous polytetrafluoroethylene
(PTFE) made in accordance with the teachings of U.S. Pat. No. 3,593,566 herein
incorporated by reference. This material is commercially available in a variety of
forms from W. L. Gore & Associates, In., of Elkton, MD, under the trademark
GORE-TEX.RTM. The expanded PTFE membrane can be made in a number of
thicknesses ranging from 0.00025 inches to 0.125 inches (6µm to 3 mm) with the
preferred thickness for the present invention being at most 1 mil (0.025 mm) and
most preferably between 0.50 mils (0.013 mm) and 0.75 mils (0.019 mm). The
expanded PTFE membrane can be made with porosities ranging from 20% to
98%, with the preferred porosity for the present invention being 70-95%. * * *
1 References are to the disclosure as reproduced in the patent under consideration and are given in the
customary column:lines format.
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