Flame-retardant composition comprising a phosphonic acid derivative

A blend comprising a synergistic mixture of (A) and (B), wherein:

• (A) is a chemical compound or a mixture of two or more chemical compounds selected from the group consisting of
• a) one or more phosphonate compound(s) according to the following formula
• wherein A1 and A2 are each independently of the other a substituted or unsubstituted straight chain or branched chain alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted benzyl, a substituted or unsubstituted phenyl, or a substituted or unsubstituted naphthyl, and
• b) alkyl- or aryl-phosphonic acids, wherein alkyl- is a straight chain or branched chain alkyl group having 1 to 4 carbon atoms, and aryl is a substituted or non substituted benzyl, substituted or non substituted phenyl, substituted or non substituted naphthyl, or a salt respectively an ester of the aforesaid phosphonic acid, and
• (B) a 1,3,5-triazine compound being poly-[2,4-(piperazine-1,4-yl)-6-(morpholine-4-yl)-1,3,5-triazine].