Appeal No. 95-4939
Application No. 08/096,345
comprises the reaction product of appellants' component (I) in
combination with the presently claimed nonaqueous liquid,
component (II). However, the examiner readily acknowledges
that Hill "does not teach of the use of a stabilizing aid
which is within the range of instantly claimed component
(III)" (page 3 of Answer). To remedy this deficiency in the
Hill disclosure, the examiner relies upon McGee for teaching a
similar antifoam composition and hydrophobic silica as a
stabilizing aid. According to the examiner, "[i]t would have
been prima facie obvious to one of ordinary skill in the art
to substitute the hydrophobic precipitated silica of McGee et
al. into the composition of Hill et al. in order to increase
the stability between components I and II of the Hill et al.
reference" (page 5 of Answer).
In our view, there are two reasons which undermine the
examiner's prima facie case of obviousness. First, Hill
expressly discloses that:
Unlike many of the silicone antifoam compositions of
the prior art, the compositions of the present
invention do not have to contain silica in order to
exhibit excellent defoaming character. This allows
for the formulation of antifoams having low
viscosities relative to systems based on mixtures of
viscous fluids and silica, thus minimizing the
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