Patent ID: 6881780

Claim:
An additive concentrate comprising a nitrogen-containing copolymer units derived from (A) from about 30% to about 60% by weight of alkyl acrylate ester monomers containing from 1 to 11 carbon atoms in the alkyl group; (B) from about 40% to about 70% by weight of alkylacrylate ester monomers containing from 12 to about 24 carbon atoms in the alkyl group; and (C) from about 0.5% to about 5% by weight of at least one nitrogen containing monomer selected from the group consisting of vinyl substituted nitrogen heterocyclic monomers, N,N-dialkylaminoalkyl acrylate monomers, N,N-dialkylaminoalkyl acrylamide monomers and tertiary-alkyl acrylamides, provided that the total equals 100%.