. . . "R1???CO???N(H)m-1(R2OH)3-m wherein R1 is a saturated or unsaturated, hydroxy-free aliphatic hydrocarbon group having from 7 to 21, preferably from 11 to 17 carbon atoms; R2 represents a methylene or ethylene group; and m is 1, 2, or 3, preferably 1." .