Abstract: Cycloolefin copolymer having a solution viscosity (eta)>=0.25 dl/g, A) comprising polymerized units of at least one polycyclic olefin, B) polymerized units of at least one olefin which comprise at least one double bond and, if desired, C) polymerized units of one or more acyclic monoolefins, wherein the equivalent weight with regard to olefinic double bonds is less than or equal to the number-average molecular weight, and which additionally contains at least one repeating unit which possesses at least two electron withdrawing groups. The cycloolefin copolymer is suitable as a coating composition and as an additive.