Appeal No. 1997-1991 Page 3
Application No. 08/376,270
8. A process for preparing an aqueous dispersion of a
polyurethane which comprises reacting, in an aqueous medium, a
reaction mixture comprising:
(a) a water-dispersible isocyanate-terminated
polyurethane prepolymer having an NCO content of between about
1.5 and 10% by weight, said prepolymer having incorporated
therein uretdione moieties and isocyanurate moieties, and
(b) an amine chain extender, in an amount sufficient to
provide an NCO/NH index for the composition of between 40 and
2
150.
15. A method for coating a substrate which comprises
contacting the substrate with a coating composition comprising
a dispersion in water of the reaction product of:
(a) a water-dispersible isocyanate-terminated
polyurethane prepolymer having an NCO content of between about
1.5 and 10% by weight, said prepolymer having incorporated
therein uretdione moieties and isocyanurate moieties, and
(b) an amine chain extender, in an amount sufficient to
provide an NCO/NH index of between 40 and 150.
2
The prior art references of record relied upon by the
examiner in rejecting the appealed claims are:
Mosbach et al. (Mosbach) 5,098,983 Mar.
24, 1992
Coogan et al. (Coogan) 5,169,895 Dec. 08,
1992
Claims 1-6 and 8-21 stand rejected under 35 U.S.C. § 103
as being unpatentable over Mosbach in view of Coogan.
OPINION
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