Appeal No. 1996-2115
Application 08/809,933
B
Claims 23, 26-27, and 29 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Candau and Zweigle. We affirm this rejection.
Candau teaches nonionic polymeric microparticles, useful in enhanced oil recovery,
made by polymerizing acrylamide and MBA to form a microlatex, having a diameter radius
less than 50 nm (particle diameter of .025 microns) ( column 1, lines
19-20 and column 2, lines 18-61). Candau discloses that the polymeric microparticles
have a high molecular weight generally above 1,000,000 (column 2, lines 49-50). Candau
further teaches the viscosity of the system is low (column 2, lines 33-36 and column 4, lines
35-40).
Candau fails to expressly describe the amount of MBA to be added to the polymeric
microparticles. In addition, Candau fails to directly teach that the solution viscosity of the
microparticles is at least about 2.0 mPa.s. Finally, Candau is silent as to whether the
polymeric microparticles are water-soluble.
Zweigle, like Candau, is directed to polymeric microparticles useful in enhanced oil
recovery operations (column 2, lines 25-28 and 45-50). Zweigle adds MBA ( a
cross-linking agent) during the formation of polymeric microparticles from monomers such
as acrylamide in an amount that is sufficient to cross-link the polymer to form a discrete,
spheroidal, water-swellable microgel (column 4, lines 1-20), i.e., the amount
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