Appeal 2006-2400
Application 10/051,814
cationic (positively charged), they are deposited and retained
well when directly added to the aqueous pulp slurry. Such
“wet-end addition” is highly desirable in papermaking.
Subsequently in the papermaking process, these resins cross-
link and eventually become insoluble in water. When this
occurs, the wet-strength resin acts as a “glue” to hold the fibers
of the paper together. This results in the desired wet-strength
property. Pregozen at col. 1, ll. 51-57 and col. 2, ll. 14-25.
It can be inferred from the above teaching that the anionic surface
charge on a flexible absorbent nonwoven product containing a cellulosic
material is a result effective variable (affects the binding of a cationic
material) and is reduced upon reacting with a cationic polymer binder. In re
Boesch, 617 F.2d 272, 276, 205 USPQ 215, 219 (CCPA 1980)(“[D]iscovery
of an optimum value of a result effective variable in a known process is
ordinarily within the skill of the art.”). Moreover, the Appellants do not
dispute the Examiner’s finding that:
Noda et al teach that cationically modified styrene-butadiene
latexes[,] especially with nonionic or preferably cationic
surfactants added to the latex to have adequate colloidal
stability, can be used as a binder for treating cellulosic fibers to
provide the desired wet strength by binding to negatibvely [sic.
negatively] charged cellulosic fibers (See column 1, lines 13-
18, 51-57; column 2, lines 3-25, 54-69). In other words, Noda
et al teach that cationically modified styrene-butadiene latexes
especially with nonionic or preferably cationic surfactants are
suitable for treating cellulosic fibers to provide the desired wet
strength. [Emphasis original.] Answer at 4.
Given Pregozen’s and Noda’s interest in improving the wet strength
of a flexible absorbent nonwoven product and Noda’s teaching regarding the
loading and/or binding effect of the anionic surface charge of a nonwoven
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