The invention relates to a copolymer obtainable by copolymerizing (A) at least one unsaturated dicarboxylic acid or the derivatives thereof, (B) at least one a-olefin comprising 6 to 20 carbon atoms, (C) at least one C3- to C20-alkyl ester of acrylic acid or methacrylic acid or a mixture of such alkyl esters, and (D), optionally, one or more additional copolymerizable monomers different from monomers (A), (B) and (C), whereupon at least one dialkylamine (E) is converted, the two alkyl groups of the at least one dialkylamine (E) independently being alkyl groups having 17 to 30 carbon atoms. The invention further relates to a method for synthesizing a copolymer and to the use thereof, inter alia, for reducing crystallization of paraffin crystals in fuels.