Pierre Gaudon

Fire resistance and mechanical properties of a huntite/hydromagnesite/antimony trioxide/decabromodiphenyl oxide filled PP-PE copolymer

A natural mineral filler containing mainly huntite and hydromagnesite together with a blend of antimony trioxide (Sb2O3) and decabromodiphenyl oxide (DBDPO) was used to reduce the flammability of an ethylene-propylene copolymer. At the same time it was desirable to improve the stiffness of the copolymer without damaging its impact resistance even at high filler content. All the components and the resulting composites were studied by differential thermal (DTA) and thermogravimetric analysis (TGA). Specific flammability tests and mechanical tests were also carried out on the composites. The influence of the mineral filler and/or the Sb2O3/DBDPO blend on copolymer properties was investigated. The best results were obtained by combining both of the main components to give 25% mineral filler and 20% Sb2O3/DBDPO blend.

Talcs and brominated trimethylphenyl indane/Sb2O3 blend in a PP-PE copolymer

Several fillers containing various percentages of talc were incorporated at 40% loading, and at 20% in combination with 20% of a brominated flame retardant system in a PP-PE copolymer. Fire resistance and mechanical properties were studied. Ignition time at dripping test, UL 94 behaviour, and tensile yield stress are improved by the use of fillers with high percentages in talc, low median diameter and high lamellarity index. These correlations are interpreted by the crystallisation ability of talc which creates a strong filler-polymer adhesion. The melting of this crystalline phase around the filler is expected to protect the filled material when a heat source is applied. Mixed compositions with micronic and quite pure talc exhibit V0 class at the UL 94 test and interesting tensile and flexural mechanical properties.