Patent ID: 7847044

Claim:
A method of producing copolymers, the method comprising: (a) providing at least one water-soluble N-vinyllactam and at least one hydrophobic comonomer; and (b) free-radical polymerizing the at least one water-soluble N-vinyllactam and the at least one hydrophobic comonomer in an organic solvent in the presence of an initiator, wherein the polymerization is carried out at a gauge pressure such that evaporation of the organic solvent and the at least one hydrophobic comonomer is avoided, and wherein the polymerization is carried out using the feed-method with metered addition of the at least one water-soluble N-vinyllactam and the at least one hydrophobic comonomer into the polymerization, to form the copolymers having a FNU value of less than 20.