Appeal No. 1997-0227
Application No. 08/113,147
Fryd '192 discloses two classes of grafting agents (col.
6, lines 1-26):
One class of grafting agents which can be used
to practice the invention includes compounds having
at least one acrylate or methacrylate group and at
least one additional moiety which is capable of
undergoing free radical polymerization at a rate
substantially slower than the polymerization of the
acrylate or methacrylate group.
The term "substantially slower" means that the
polymerization rate of the additional moiety is so
slow that it remains substantially unreacted after
polymerization of the microgel core has been
completed. Thus, the additional moiety provides
pendant sites for free radical attack during
polymerization of the shell. . . .
A second class of grafting agents which can be
used to practice the invention includes compounds
which contain residual unsaturation after
polymerization. Examples of such compounds include
conjugated dienes, such as butadiene.
At best, the grafting agents of Fryd '192 are viewed as a
bridge, chemically bonding the core and the shell through
unreacted moieties. In contrast, the core and shell in the
claimed microgel are not chemically linked but rather are
substantially distinct from one another.
Nevertheless, the examiner argues that (Answer, p. 12):
It is reasonable to presume that there . . . is at
least one unreacted butadiene monomer remaining in
the core, since polymerizations rarely go to
completion. The instant claims are not limited by
the amount of unreacted elastomeric monomer that
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