Appeal No. 1997-1684
Application No. 08/223,916
catalyst system which includes a conventional Ziegler-Natta
catalyst, an organoaluminum co-catalyst and an organosilane
electron donor, much like the process claimed by appellants.
Additionally, each of the primary references disclose
specific organosilane electron donors in both of the
categories (ED1 and ED2) defined by appellants' claims. For
example, diisopropyl dimethoxysilane (DIDS), an ED1 compound,
is disclosed in Shamshoum (column 6, lines 20-22) and Hoppin
(column 1, lines 59-60). Likewise, cyclohexylmethyl
dimethoxysilane (CMDS), an ED 2 compound, is disclosed in
Shamshoum (column 4, line 14) and Hoppin (column 9, Table I,
example J).
The primary issue in contention is the obviousness of
using a mixture of an ED 1 compound and an ED 2 compound in a
propylene polymerization process. We agree with the examiner
that it would have been prima facie obvious, within the
context of 35 U.S.C.
§ 103, to combine two compounds, each of which having been
individually disclosed by the prior art as useful for the same
purpose, to form a composition to be used for the very same
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