Patent ID: 7173085

Claim:
An aqueous emulsion comprising a water-dispersible copolymer which is non-dispersible in aqueous solutions containing 0.5% or more of an inorganic salt, wherein the water-dispersible copolymer comprises in percentages by weight: (A) from about 10% to about 90% of an acidic ethylenically unsaturated monomer; and (B) from about 10% to about 90% of an ethylenically unsaturated monomer selected from the group of monomer formulas consisting of: (i) CH 2 â•C(R 1 )COR 2 ; (ii) R 3 OOCâ€”CHâ•CHâ€”COOR 4 ; (iii) CH 2 â•C(R 5 )OCOR 6 ; (iv) CH 2 â•C(COOR 7 )CH 2 COOR 8 ; (v) CH 3 CHâ•CHCOOR 9 ; (vi) R 10 C 6 H 4 CR 11 â•CHR 11 ; and (vii) R 12 CHâ•CHR 13 ; wherein R 1 is hydrogen or methyl and R 2 is â€”OZâ€² or â€”N(Zâ€³)(Zâ€³), wherein Zâ€² is an alkyl group having from 1 to 7 carbon atoms, and Zâ€³ is independently selected from the group consisting of hydrogen and alkyl groups having from 1 to 6 carbon atoms; R 3 and R 4 are independently hydrogen or an alkyl group having from 1 to 7 carbon atoms, with the proviso that R 3 and R 4 are not both hydrogen; R 5 is hydrogen or methyl and R 6 is an alkyl group having from 1 to 7 carbon atoms; R 7 and R 8 are independently hydrogen or an alkyl group having from 1 to 7 carbon atoms, with the proviso that R 7 and R 8 are not both hydrogen; R 9 is an alkyl group having from 1 to 7 carbon atoms; R 10 and R 11 are hydrogen; R 12 and R 13 are independently selected from the group consisting of hydrogen, â€”CN, â€”NHCHO, â€”NHCOCH 3 , and an alkyl group having from 1 to 7 carbon atoms; and the copolymer has a weight average molecular weight greater than about 25,000 and is present in an amount from about 20% to about 70%.