For the blends according to the invention suitable cycloolefin polymers (A) comprise structural units that are derived from at least one monomer of the formulae I to VII ##STR5## where R1, R2, R3, R4, R5, R6, R7 and R8 are the same or different and are a hydrogen atom or a C1 -C8 -alkyl radical, the same radicals in the various formulae being able to be different, and n is an integer from 2 to 10.