Appeal No. 1998-2300
Application No. 08/366,762
Menashi discloses a process for producing non-porous, dense, silica particles
wherein a dried cake is formed during an intermediate step. (Column 5, line 54 to column
6 line 5).
Gonzalez-Oliver discloses providing an oxidizing atmosphere with air, oxygen,
chlorine, or a mixture of these gases with helium or argon and with other halogen
compounds that contribute to dehydroxylation of silica glass. (Column 12, lines 16-29).
The Examiner cited the Garcia reference for the proposition that fumed silica is
hydrophilic in nature due to the large number of hydroxyl groups present on the surface
when produced by hydrolysis of silicon tetrachloride in a flame process. (Examiner’s
Answer, page 9, second paragraph).
The Examiner asserts the claimed invention is unpatentable over the combination of
Mehrotra, Menashi, Gonzalez-Oliver and Garcia. According to the Examiner, Mehrotra
discloses a process for producing pure and dense amorphous synthetic silica by calcination
of agglomerated particles of amorphous silica in two steps. (Examiner’s Answer, pages 4
and 5). The Examiner asserts the process of Mehrotra differs from the claimed invention
in (1) the formation of porous caked mass as in steps (a)-(c) and (2) the use of chlorine or
thionyl chloride atmosphere for the first sintering step. (Examiner’s Answer, page 7 first
paragraph). To remedy the deficiencies of Mehrotra, the Examiner relies on Menashi to
provide motivation for the intermediate use of a dried silica cake; and the combination of
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