. . "H2 --CH2 --NH--), iminopropylene ##STR4## and the like, desirably 2 or 3, and particularly desirably 2, carbon atoms, B is oxyalkylene having 2 to 4, such as oxyethylene (--CH2 CH2 --O--), oxypropylene (--CH2 CH2 CH2 --O-- or ##STR5## and the like, desirably 2 or 3, and particularly desirably 2, carbon atoms, m is an average number in the range of 0.1 to 10, preferably 0.4 to 8, n is 0 or an avera" . . .