Appeal No. 2001-0080
Application No. 08/577,217
in a range of about 150 to about 210, and "a medium particle
size of an average" of about 20 to about 50 nm. (Column 1,
lines 50-63.)
Bergh describes the use of silica having an ultimate
particle size of 50 to 10,000 angstroms and a BET surface area,
as measured using nitrogen gas, of about 100 to about 200 in
sulfur vulcanized tread compositions. (Column 2, line 49 to
column 3, line 4; column 4, lines 24-32.)
Aminabhavi teaches that the electrical resistivity of
rubbers is known to be largely influenced by the type and amount
of carbon black in addition to its degree of dispersion in the
rubber matrix. According to the examiner (examiner's answer,
page 6), this reference "clearly shows that the ordinary artisan
understands the impact of particle size and 'structure' on
resistivity/conductivity of rubber and particularly that high
conductivity is achieved by selecting small particle size and
'high structure' carbon blacks..." (Footnote omitted.)
In comparing the disclosure of Hanson, the principal prior
art reference (examiner's answer, page 6, statement of
rejection), to the subject matter of appealed claim 1, we find
that Hanson differs in many respects. For one, Hanson does not
teach any average particle size for the carbon black. Nor does
Hanson teach any particular DBP oil absorption value for the
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