rylate or methacrylate, and a perfluoroalkyl group-containing urethane compound represented by the formulas (3) to (6): ##STR25## wherein Rf is perfluoroalkyl group having 4 to 20 carbon atoms, X is --CH2 CH(A)Cj H2j --, Ck H2k - or --SO2 N(R7)Ct H2t -- wherein A is hydrogen, lower alkyl, hydroxyl or lower alkylcarbonyloxy, j is an integer to 0 to 4, k and t are an integer of 1 to 4 and R7 is hydr