Patent ID: 7416831

Claim:
A co-polymer comprising K units and L units: the K units are selected from —[CH 2 C(R 1 )C(O)(OCH 2 CH(R 5 )) m OR 2 ]—, —[CH 2 C(R 3 )CO 2 H]—, and mixtures thereof; the L units are selected from —[CH 2 C(R 4 C(O)(OCH 2 CH(R 6 )) n OP(O)(OH) 2 ]—, —[CH 2 CH 2 PO(OH) 2 ]—, and mixtures thereof; R 1 is hydrogen or methyl; R 2 is hydrogen or an alkyl group of one to four carbon atoms; R 3 is hydrogen or methyl; R 4 is hydrogen or methyl; and R 5 and R 6 are each independently hydrogen, methyl, or chloromethyl; m is 1 to about 30; and n is 1 to about 15; and the co-polymer comprises about 50 wt % to 90 wt % of the K units and about 10 wt % to about 50 wt % of the L units.