consisting of amino acrylate of the formula: ##STR8## wherein R is hydrogen or methyl, R1 is hydrogen or alkyl of 1 to 4 carbon atoms, R2 is alkyl of 1 to 4 carbon atoms, and n is an integer of 1 to 4 inclusive, a homopolymer of said amino acrylate, and a random copolymer of ethylene and 20 to 40 percent by weight of said amino acrylate compound, each of compounds (b), (c) and (d) being compatible