. . "Most preferably, R1 is a linear or branched alkyl group having from about 8 to about 22 carbon atoms and R4 is a linear or branched alkyl group having from 1 to about 6 carbon atoms, R2 in each of the x (R2O) and y (R2O) groups is independently ethylene or propylene, R3 is hydrogen or methyl, and x is an average number from about 2 to about 15, or R1 and R4 are independently a linear or branched a" . .