Patent ID: 8895478

Claim:
A polymer derived at least from: (A) from about 1% to about 99% of at least one N-vinyl amide-based unit and/or at least one acrylamide-based unit, and (B) from about 11.6% to about 99% of at least one unit comprising: (i) at least one hydroxyl group, and/or (ii) at least one functional group convertible to a hydroxyl group wherein at least one group is converted to hydroxyl functionality in the final polymer product; wherein said polymer comprises from about 1% to about 99% of at least one ester group, and wherein said polymer is not poly(N-vinyl-2-pyrrolidone)-block-polyester copolymers or other diblock and triblock copolymer consisting of poly(N-vinyl-2-pyrrolidone) as one block.