Appeal No. 1997-1997
Application No. 08/263,496
1. A liquid polyisocyanate prepolymer comprising the
reaction product of an organic polyisocyanate blend and a
polyoxypropylene polyether polyol, said polyisocyanate
blend comprising
A) a diphenylmethane diisocyanate component comprising
from 50 weight percent to 98 weight percent
4,4N-diphenyl-methane diisocyanate, from 2 weight
percent to 50 weight percent 2,4N-diphenylmethane
diisocyanate, and less than 10 weight percent
2,2N-diphenylmethane diisocyanate, said weight
percentages based on the total weight of the
ingredients in A);
B) a polymethylene polyphenyl polyisocyanate component
comprising from 30 weight percent to 70 weight percent
diphenylmethane diisocyanate, the remainder comprising
polymethylene polyphenyl polyisocyanates having
functionalities greater than two, said weight
percentages based on the total weight of the
ingredients in B);
C) and optionally a uretonimine-carbodiimide modified
diisocyanate component comprising from 10 weight
percent to 35 weight percent uretonimine-carbodiimide
species, the remainder comprising essentially pure
4,4,N- diphenylmethane diisocyanate, said weight
percentages based on the weight of the ingredients in
C);
said polyoxypropylene polyether polyol having a number average
molecular weight ranging from greater than 1500 to 10,000 and
an average functionality from 1.6 to about 3, wherein the
polyol is reacted with the polyisocyanate blend at
temperatures less than 80EC, the liquid polyisocyanate
prepolymer having an overall NCO content of from 22 weight
percent to 31 weight percent.
In the rejection of the appealed claims, the examiner
relies upon the following references:
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