COMPOSITIONS BASED ON SELF-EXTINGUISHING EXPANDABLE VINYL AROMATIC POLYMERS

摘要

The present invention relates to a composition based on self-extinguishing expandable vinyl aromatic polymers, which comprises: a) a polymer obtained by the polymerization of one or more vinyl aromatic monomers present in an amount ranging from 50% to 100% by weight, and a monomer copolymerizable with the vinyl aromatic monomers, homogeneously englobed in the polymer in an amount ranging from 0% to 50% by weight; b) at least one expandable system in an amount ranging from 3% to 10% by weight, calculated with respect to the polymer (a); c) at least one flame-retardant additive in an amount ranging from 0.005% to 5% by weight, calculated with respect to the polymer (a), and containing at least 30% by weight of bromine, said amount being calculated with respect to the flame-retardant additive; d) at least one synergetic additive containing a C-C or C-O-O-C thermolabile bond in an amount ranging from 0.001% to 2% by weight, calculated with respect to the polymer (a); and e) at least one athermanous additive selected from carbon-black, a graphite, a carbon coke in particle form and mixtures thereof; said composition is characterized in that it contains a stabilizing additive including at least one tin alkyl mercapto-ester having a purity higher than or equal to 95%.