Solutions of new antimony complexes

Claim 1

A process for the production of a solution of a substantially water-insoluble complex antimony compound in a polar organic solvent which comprises esterifying an α-hydroxy polycarboxylic acid with a polyol in a molar ratio of the carboxyl groups to the hydroxyl groups in the polyol of at least 2 : 1 and in the presence of an acid transesterification catalyst; reacting an excess of the esterification product with an antimony oxide in a polar organic solvent at a temperature in the range of from 100° to 200° C to form a clear solution still containing free carboxyl groups; and adding a monoisocyanate to the solution at a temperature below 100° C in such a quantity that the free carboxyl groups are converted into the corresponding amide groups the monoisocyanate corresponding to the general formula R.sub.1 -N=C=O in which R 1 is a straight-chain or branched alkyl group having from 1 to 20 carbon atoms, or ##STR3## in which R 2 , R 3 , R 4 , R 5 and R 6 may be the same as or different from one another and may represent a member selected from the group consisting of hydrogen, an alkyl having from 1 to 5 carbon atoms, fluorine, chlorine or bromine.