Appeal No. 95-1568
Application 08/124,747
known and each has been individually used in rubber making compositions (Page 1 of
specification). Appellants also indicate that when copolymer gums (A) and (B) are
used in combination a compatibility problem arises; namely that, phase separation
often occurs between the two resulting in a composition having substantially lower
mechanical strength. Appellants have solved this problem by adding to the
composition a certain block copolymer, (C). Appellants also add fumed silica (D) and a
curing agent (E) to the composition.
Evans’ 811 is directed to a heavy molecular weight (HMW) fluorosilicone
heat cured rubber composition produced by adding a silicone monomer, a chain
modifier mixture of siloxane polymers and a siloxane monomer and a catalyst to a
reactor, heating to initiate the reaction thus forming a base polymer (A), and mixing into
the base polymer, polydimethylsiloxane gum having vinyl groups (B), simultaneously
with fumed silica and other processing aids. The purpose of the gum is to aid in the
cross-linking through the vinyl groups. Evans’ 811 HMW polymer is said to have the
general formula (III), at column 4, lines 4-28.
It is the examiner’s position that appellants’ components (A), (B), and
(C) each read on Evans ‘811 formula (III). Component A is said to be found noting
repeating units a and b of formula III, component B is said to be found noting repeating
units b and c of formula III. The examiner provides no explanation as to how
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Last modified: November 3, 2007