Appeal No. 1997-3118
Application No. 08/372,083
NL ‘507 discloses use of cationic starch as a paper
strengthening agent and teaches that neutralizing anionic
materials with polyvalent cations from compounds which can be
alum prevents the anionic materials from complexing with the
cationic starch and thereby rendering it inactive.
The examiner argues that NL ‘507 “teaches that it is
advantageous to add alum to the pulp to neutralize the anionic
trash which is the source of of [sic] the claimed surface
active carboxyl impurities derived from pulping prior to the
addition of cationic polymer (cationic starch) and a retention
aid (anionic polyacrylamide) in order to improve the strength
of the paper product” (answer, page 4). The examiner,
however, does not explain how, if the anionic materials are
prevented from complexing with the cationic starch,
appellants’ recited polyelectrolyte complex is obtained.
Also, the examiner does not explain why NL ‘507 would have
indicated to one of ordinary skill in the art that the
disclosure therein would be applicable to Smith’s anionic and
cationic polymers, and why the amount of alum used to
neutralize Smith’s anionic polymer would be within the scope
of appellants’ claim 1. NL ‘507 does not teach that the alum
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