Appeal No. 2007-0196 8
Reexamination Control No. 95/000,009
A rheological control agent comprising alumina particles having an
approximate size in the range from 27-56 nanometers
The heading comes from Congoleum's claim 1. This discussion also applies
to some of the other independent claims that are even less specific ("inorganic" for
"alumina" in claims 6 and 10; "nanometer-sized" in claim 7). Lord cites Chen
at 9:50-56:
Besides the above-described embodiments for incorporating wear-
resistant particles into a coating layer, another method of
incorporating wear-resistant particles into one or more coating layers
involves the use of fumed silica or alumina or other similar types of
materials as the suspension aid which have a submicron particle size
range. Preferably, the submicron particle size range is from 5 to about
25 nm.
Chen expressly teaches alumina, which is undisputedly inorganic. Chen
expressly prefers particles "about 25 nm". Two observations are apt. First, Chen's
"about 25 nm" is fuzzy not just in the abstract, but also in comparison with the
lower end of Chen's range (5 nm), which is not so qualified. Moreover, Chen's
entire range is simply preferred. A person having ordinary skill in the art would
not have read Chen as excluding 27 nm particles from the permissible range.
Congoleum expresses its lower bound as "an approximate size in the range
of 27…nanometers". The lower bound of this claimed range is fuzzy. The
imprecision in these proximate boundaries of Congoleum's claim and Chen's
merely preferred range, is sufficient to make out a prima facie case for obviousness
for this limitation.
Sixty micron-sized nylon 12 particles
Chen does not teach the use of 60 μm nylon 12. Chen does teach, at 4:9-24,
that suitable wear-resistant particles include aluminum oxide as well as:
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