Appeal No. 95-0757
Application 07/795,307
formation of agglomerates of primary particles which then can
easily be filtered. The preparation of fine polymer particles in
prior art processes is one of the known disadvantages of emulsion
polymerization because of the difficulty in coagulating and
separating the polymer from the latex. Thus prior art workers
have turned to the suspension polymerization technique to
overcome some of the difficulties present in the emulsion
polymerization and to produce a granular product directly. With 3
the above technical background in mind, we turn to the stated
rejections of the appealed claims.
It is well settled that the examiner has the initial burden
to establish a prima facie case of unpatentability over prior
art. In the present case, the examiner relies on the combined
teachings of a number of prior art references but principally on
the disclosures in Flesher. According to the examiner (Answer,
page 3), Flesher teaches emulsion polymerization of small
diameter water soluble polymers using a combination of
emulsifiers, crosslinking agents and free radical initiators. As
accurately argued by appellants, however, Flesher’s disclosed
process involves the reverse-phase suspension polymerization of
3 See Polymers and Resins by Brage Golding, Ph.D., D. Van Nostrand
Company, Inc., Princeton, New Jersey, pages 134 and 142, copyright 1959, copy
attached.
5
Page: Previous 1 2 3 4 5 6 7 8 Next
Last modified: November 3, 2007