Appeal No. 1995-4997
Application No. 08/089,436
5. In a water-carrying system subject to the formation
of scale, the improvement comprising the water in said water-
carrying system comprises from 0.1-100 ppm of a phosphono-
methylated polyvinylamine which contains as characteristic
structural elements, units of the formula
wherein R is1 hydrogen, C -C -alkyl or1 6
and X is hydrogen an alkali metal, ammonium or one equivalent
of an alkaline earth metal;
wherein said polymer has a K value of from 10 to 100.
The examiner relies upon the following references as
evidence of obviousness:
Hwa 856,193 Nov. 17, 1970
(Canadian patent)
Justice et al. (Justice) 4,830,837 May 16, 1989
Appellants' claimed invention is directed to a method of
inhibiting scale deposition in a water-carrying system by
-2-
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