The present invention relates to a
flame retardant preparation containing A) a cyclic
phosphazene according to formula (1), where R is identical or different and in each case represents - C1- to C8-
alkyl, preferably methyl, ethyl, propyl or butyl, - C1- to C8-alkoxy, preferably methoxy, ethoxy, propoxy or butoxy, - optionally C5- to C6-cycloalkyl substituted by
alkyl, preferably C1-C4-
alkyl, - optionally C6- to C20-aryloxy, preferably phenoxy, naphthyloxy, substituted by alkyl, preferably C1-C4-alkyl and / or hydroxy, - optionally C7- to C12-aralkyl, preferably phenyl-C1-C4-alkyl, substituted by alkyl, preferably C1-C4-alkyl, or - an OH group, and k represents 0 or an integer from 1 to 15, preferably a number from 1 to 10, B) a
polymer containing structural units containing Brønsted acid groups, wherein the content of structural units containing Brønsted acid groups in component B is at least 50 wt. % and wherein at least some of the Brønsted acidic groups are deprotonated. The invention also relates to a composition containing the
flame retardant mixture and a
polymer, to use of the
flame retardant mixture for reducing the burning drip of polymers in a flame retardant test, to a
thermoplastic molding compound produced from the composition, and to molded bodies containing the composition or obtained from the
thermoplastic molding compound.