Appeal No. 2005-1693
Application No. 10/192,333
produced by this process are said to show chemical instability as well as potentially reactive
surface sites due to residual unpaired electrons from the polymerization process. Specification at
5, lines 1-9.
According to the appellant (Specification at 5, lines 23-27):
[A] fluorocarbon (CF2)n-type (i.e. PTFE-type) polymer thin film having enhanced
chemical and mechanical stability can be realized by forming the fluorocarbon
polymer film through a thermal CVD method in which a monomer gas is
pyrolyzed to generate a source of polymerizable CF2 species.
The steps of the appellant’s thermal CVD process are:
a) exposing a monomer gas to a source of heat having a temperature sufficient to
pyrolyze the monomer gas, the monomer gas selected to produce upon pyrolysis a source of
reactive species that includes polymerizable CF2 species and that selectively promotes CF2
polymerization, the reactive species source being in the vicinity of the surface on which the
fluorocarbon polymer film is to be formed; and
b) maintaining the surface substantially at a temperature lower than that of the heat
source to induce deposition and polymerization of the CF2 species on the surface. See claim 2.
Preferably, the monomer gas includes hexafluoropropylene oxide. Specification at 7, lines 1-2.
The fluorocarbon (CF2)n-type polymer thin films produced by this process are said to
have a high compositional CF2 fraction and a low degree of cross-linking density. Specification
at 7, lines 23-27. Thus, the films are flexible, i.e., non-brittle, and exhibit superior mechanical
stability. According to the appellant, “This is especially desirable for the operation of movable
or flexible components or assemblies, in particular valves and their individual components.” See
3
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