Appeal No. 94-4409
Application 07/958,526
drilling fluid composition containing, as a drilling fluid
additive, a water soluble copolymer containing, inter alia,
vinyl imidazole, as a required monomeric constituent.
According to Uhl, the polymers of his invention have excellent
calcium tolerance and excellent thermal stability compared
with commercial fluid additives. However, even if objective
evidence were of record demonstrating that the vinyl imidazole
component of the prior art polymer were the sole causative
agent for the enhanced properties reported by the Uhl patent,
this fact alone would not lead one to the conclusion that the
presence of a vinyl imidazole monomer in the claimed polymer
would materially affect the basic and novel characteristics of
the claimed composition. Accordingly, given the above claim
construction, that Uhl arguably fails to teach or make obvious
the use of a polymer
prepared from a monomeric mixture ?free of appreciable vinyl
imidazole monomer? is not basis for distinguishing the claimed
subject matter from the prior art.
Appellants’ second major argument on appeal concerns the
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