Appeal No. 2005-1245
Application No. 09/839,762
silica in view of the small particle sizes of 3 to 10 nm (id.).1
In the statement of the rejection, the examiner does not
explain why the disclosure of a “number average particle size” of
3 to 10 nm by GB ‘527 would anticipate or render obvious the
claimed limitation of “a mean agglomerate particle size of less
than about 25 microns.” However, in response to appellants’
arguments (Answer, pages 4-5), the examiner finds that it was
“known that particles adhere to one another to form aggregates,
which combine to form agglomerates.” From this finding, the
examiner assumes “for the sake of argument” that 2500 particles
of GB ‘527 adhere to one another to form an agglomerate, with all
particles of the maximum 10 nm size, thus forming an agglomerate
particle size of 25000 nm (i.e., 25 microns). The examiner
further reasons that lesser size primary particles (e.g., 3 nm)
will produce still smaller agglomerates (Answer, page 4). The
examiner finally concludes that it is “reasonable to assume” that
there cannot be more than 2500 particles adhering together to
form an agglomerate and thus the silica powder of a number
1The examiner recognizes that GB ‘527 fails to disclose
hexamethyldisilazane as the “hydrophobing agent” for treatment of the
metal oxide, with regard to claim 12 on appeal (Answer, page 4).
Therefore the examiner applies GB ‘915 for its teaching of surface-
modified pyrogenically produced mixed oxides comprising silica
modified with a class of silazanes (id.). Accordingly, GB ‘915 does
not remedy the deficiencies noted infra in the examiner’s rejection.
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