Patent ID: 7745546

Claim:
A copolymer of the formula: wherein, independently, R 1 is C 1-8 a hydrocarbon radical; R 2 is a C 2 -C 4 hydrocarbon diradical; R 3 is a C 2 -C 52 hydrocarbon diradical, wherein at least 50% of the diradicals are derived from dimer acid; R 4 is selected from C 2 -C 8 hydrocarbon diradicals and polyether diradicals of the formula: —(R 11 —O) g —R 11 —, wherein R 11 is a C 2 -C 4 hydrocarbon diradical independently selected at each occurrence and g is an integer ranging from 2 to 50; Z is selected from O and NH; x and z are integers from 2 to 100; and y is an integer equal to 1 or more that provides a copolymer molecular weight of from 2,000 to 50,000.