Appeal No. 94-4409
Application 07/958,526
points out that copolymers according to his invention are
excellent when used as a drilling fluid additive during
drilling operations, and that the products covered by the Uhl
invention have a favorable impact especially ?in applications
for critical drilling operations under difficult conditions at
great depths and in the presence of formation water with a
very high content of electrolytes? (column 7, lines 16 through
20). Thus Uhl, in our view, fairly suggests the use of his
materials in drilling operations encountering ?hostile
conditions? as defined by certain of the appealed claims.
Appellants’ third major argument on appeal is that Uhl
fails to teach or make obvious what is alleged to be
unexpected stabilizing properties imparted to a polymer
prepared from an unsaturated amide monomer of designated
formula (e.g., an acrylamide) by the addition of an N-vinyl
lactam to the monomeric mixture when the polymer is
subsequently exposed to conditions conducive to hydrolysis.
As evidence of this unexpected result, appellants refer to the
specification at page 31, lines 5 through 14 and three papers
attached to their Brief as Exhibit B which indicate, inter
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