Appeal No. 94-0822
Application No. 07/801,992
1. A process for preparing an aqueous dispersion of
composite particles, the composite particles each comprising a
plurality of polymeric latex particles adsorbed onto a
titanium dioxide particle, the process comprising:
a) suspending polymeric latex particles in an aqueous
medium, the polymeric latex particles having been polymerized
in the absence of titanium dioxide particles;
b) suspending titanium dioxide particles in the aqueous
medium, the sign of the surface charge of the polymeric latex
particles being the same as the sign of the surface charge of
the titanium dioxide particles, the surface potential of one
of either of the polymeric latex particles or the titanium
dioxide particles in the aqueous medium being greater in
absolute value than the surface potential of the other of the
polymeric latex particles and the titanium dioxide particles;
and
c) mixing the aqueous medium containing the titanium
dioxide particles and the polymeric latex particles in the
absence of conditions providing gross heterocoagulation, the
polymeric latex particles adsorbing onto the titanium dioxide
particles in a controlled manner to provide the composite
particles.
In the rejection of the appealed claims, the examiner
relies upon the following references:
Pons et al. (Pons) 4,110,285 Aug. 29, 1978
Martin 4,771,086 Sep. 13, 1988
Visca et al. (Visca) 4,798,854 Jan. 17, 1989
Appellants' claimed invention is directed to a method for
preparing an aqueous dispersion of composite particles. The
composite particles comprise a plurality of polymeric latex
particles adsorbed on a single titanium dioxide particle. The
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