R3 in the above formula is a group represented by the alkylenoxy radical Z, wherein A and x are as defined with respect to R1; and Y is the anion, R???SO3, wherein R??? is a C1-C18alkyl, preferably a C1-C2alkyl, e.g. methyl and ethyl or a C8-C18 alkylphenyl, preferably a C10C13 alkylphenyl.