W. R. Grace Co.-conn.

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Lai-Duien Grace Fan

This invention relates to a method of inhibiting scale formation in aqueous systems wherein allylphosphonate copolymers are added to the system in an amount effective to inhibit scale formation. The allylphosphonate copolymers of this invention exhibit characteristic properties for the treatment of aqueous systems, namely strong calcium complexation, excellent iron dispersion, inhibition of calcium carbonate scale and inhibition of calcium phosphate deposition.

Method of inhibiting scale deposits

This invention relates to water-soluble allylphosphonate copolymers which are useful for treating aqueous systems. The allylphosphonate copolymers are characterized as having the formula: ##STR1## wherein the molar percentage of x in the copolymer is from 1 to 90 percent, the molar percentage of y in the copolymer is from 10 to 99 percent, and the total of x and y being 100 percent; and wherein each R.sup.1 is independently selected from the group consisting of hydrogen, lower alkyl groups having from 1 to about 4 carbon atoms and a salt forming cation, R.sup.2 and R.sup.3 are independently selected from the group consisting of hydrogen, halogen, COOH, CH.sub.2 COOH, lower alkyl groups having from 1 to about 4 carbon atoms, and phenyl, and A is selected from the group consisting of COOH, CH.sub.2 COOH, .phi.COOH, SO.sub.3 H, CH.sub.2 SO.sub.3 H, CH(CH.sub.3)SO.sub.3 H, CH.sub.2 OCH.sub.2 CH(OH)CH.sub.2 SO.sub.3 H, .phi.-SO.sub.3 H, ##STR2## wherein n=2 to 4, CONH.sub.2, CONHCHH.sub.3, CON(CH.sub.3).sub.2, CONHCH.sub.2 OH, CONHCH(OH)COOH, CONHC(CH.sub.3).sub.2 CH.sub.2 SO.sub.3 H, COO(CH.sub.2).sub.n SO.sub.3 H, wherein n=2 to 4, and CO(OCH.sub.2 CH.sub.2).sub.n OH wherein n=1 or more, water soluble salts of sulfonate and carboxylate groups.

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Columbia, MD, United States of America

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