Appeal No. 95-0757
Application 07/795,307
polymer powder comprising:
(i) polymerizing water-soluble monomers in the
aqueous phase of a water-in-oil emulsion in the presence of
(a) a water-in-oil emulsifier;
(b) from 50 to 5,000 ppm of at least one crosslinking
agent;
(c) from 1 to 20% by weight, based on the monomers
employed in the polymerization of at least one oil-in-water
emulsifier; and
(d) free-radical polymerization initiators;
(ii) adding a protective colloid to the water-in-
oil emulsion in an amount of from 0.1 to 10% by weight, based on
the polymer, after the polymerization is complete;
(iii) removing water from the resultant water-in-oil
polymer suspension by azeotropic distillation; and
(iv) isolating the suspended finely divided polymer
powder;
wherein sorbitan esters are not employed as both said water-
in-oil emulsifier and said protective colloid and
wherein said finely divided polymer powder consists of an
agglomeration of primary particles having a mean particle size of
from 0.1 to 20 Fm.
9. A finely divided crosslinked polymer powder
comprising agglomerates of primary particles which have a mean
particle size of from 0.1 to 20 Fm, wherein the agglomerates,
when introduced into water, disintegrate into the primary
particles and wherein the polymer powder is obtained by the steps
comprising:
(i) polymerizing water-soluble monomers in the
aqueous phase of a water-in-oil emulsion in the presence of
2
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Last modified: November 3, 2007