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US 4,357,245 AGranted
Water-soluble copolymer and its preparation
AssigneeCassella Aktiengesellschaft
InventorsFriedrich Engelhardt, Ulrich Riegel, Martin Hille, Heinz Wittkus
Life of this patent
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Abstract
Outstandingly suitable drilling mud additives are water soluble copolymers consisting essentially of a random distribution of (a) 5 to 95% by weight of units of the formula ##STR1## (b) 5 to 95% by weight of units of the formula ##STR2## and (c) 0 to 80% by weight of units of the formula ##STR3## wherein R.sup.1 and R.sup.2 are the same or different and each is hydrogen methyl or ethyl; and X.sup..sym. is a cation.
Claims2
An aqueous drilling mud containing 0.5 to 40 kg/m.sup.3 of a water-soluble copolymer consisting essentially of a random distribution of
- (a) 5 to 95% by weight of units of the formula ##STR10## (b) 5 to 95% by weight of units of the formula ##STR11## and (c) 0 to 80% by weight of units of the formula ##STR12## wherein R.sup.1 and R.sup.2 are the same or different and each is hydrogen, methyl or ethyl;
- and
- X.sup..sym. is a cation.
Dependencies are inferred from the claim text.