The invention relates to compositions that contain A) one or more copolymers, said copolymers containing one or more structural units obtained from a) 19.9 to 75.9 wt.% glycerin, b) 0.1 to 30 wt.% at least one dicarboxylic acid, and c) 24 to 80 wt.% at least one monocarboxylic acid according to formula (I) R