The invention relates to a polymer or oligomer comprising a) An oligomeric or polymeric core comprising carbon atoms and at least one of oxygen atoms and nitrogen atoms, and b) at least three hydrocarbyl terminal and/or pending groups having 12 to 100 carbon atoms, wherein the hydrocarbyl groups are linked to the core via c) a linking moiety comprising i) a urethane group and ii) a group selected from urethane group, urea group, and biuret group.