Polyphosphates and process of preparation

Claim 1

A process for the production of branched polyphosphates having relative viscosities of rel=1.010 to 1.200 (in CH 2 Cl 2 , c=5 g/l), characterised in that from 1 to 100 ml % of one or more aromatic diols corresponding to formula (1): ##STR9## wherein X represents a C 1 -C 5 alkylene or alkylidene radical, a C 5 -C 6 cycloalkylene or cycloalkylidene radical, a single bond, --S-- or a radical corresponding to formula (1a): ##STR10## wherein the two alkylene substituents may be in the o, m or p position relative to each other, and from 99 to 0 mol % of hydroquinone, resorcine or an aromatic diol corresponding to formula (2): ##STR11## wherein R represents hydrogen, halogen as chlorine and bromine and C 1 -C 3 alkyl with the provision that at most three alkyl groups are present, X has the meaning as given in formula (1) are reacted with at least one phosphoric acid ester corresponding to formula (3): ##STR12## wherein Y represents the same or different alkyl-, cyclo- alkyl-, aryl- and alkylaryl-radicals and wherein the ratio of aromatic diol to phosphonic acid ester is from about 0.66:1 to 2.3:1 in the presence of basic alkali metal or alkaline earth metal compounds with the release of alcohols and/or phenols at a temperature of from 80° to 350° C.