alkenyl group having 2 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, and R2 is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms; and (b) a vinyl resin having at least one silyl group substituted with a hydrolyzable group or hydroxyl in an amount of 2 to 300 weight parts.