Appeal No. 2006-3224 Page 6
Application No. 10/063,656
1 to about 15 microns,” the Examiner cites Callegaro and Grinstaff for teaching particles
of the claimed size which are utilized in a biomedical environment. Id.
Appellants argue that “Rembaum is directed to a conventional emulsion
polymerization process for forming the polymer microsphere, not an emulsion/
aggregation process as required in the claimed invention.” Brief, page 9.
The claimed emulsion/aggregation process, on the other hand, is a
materially different process that takes polymer particles prepared by
standard emulsion polymerization techniques (such as disclosed in
Rembaum), in the general 50-500 nm size range, and aggregates them
under controlled particle growth conditions to make larger particles that
are in the size range of 1 to 15 microns (1,000-15,000 nm) with a narrow
particle geometric size distribution. The result of the claimed
emulsion/aggregation process is thus relatively larger sized particles, but
which have a narrow particle geometric size distribution, such as less than
about 1.25. Nowhere does Rembaum teach or suggest that an
emulsion/aggregation process could or should be used in place of the
disclosed conventional emulsion polymerization process.
Brief, page 12.
Rembaum describes a method of making uniformly-sized polymeric
microspheres having a selected uniform diameter below 3500 Å. Rembaum, column 1,
lines 14-16; column 2, lines 13-16. The microspheres are produced by “emulsion
polymerization.” Id., column 2, line 41. This process is described to include a step of
forming a polymerization mixture comprising monomers, catalyst, and a surface active
agent. Id., column 4, lines 10-60. The mixture is “tumbled,” and then polymerization is
initiated by applying heat to the mixture, which results in the formation of the
microspheres. Id., column 4, lines 53-65; column 10, claims 9-11. We agree with
Appellants that Rembaum’s process does not carry out “aggregating and coalescing
said polymeric resin into polymeric microspheres” as required by claim 1. Polymeric
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