. . . "U.S. Pat. No. 5,326,397 of Abdelrazig et al. disclosed at least one compound of the formula R(???O???CO???NH2)n where R=C3-C8 alkyl or C5-C8 cycloalkyl hydrocarbon when n=1 or a C2-C10 alkylene group or a group having the formula A(OA)xOA wherein each A is a C2-C3 alkylene and x is an integer of from 0 to 10 when n=2." .