Combination of the Classical Flame Retardant Filler Alumina Trihydrate with Organoclays

6 Combination of the Classical Flame Retardant Filler Alumina Trihydrate with Organoclays 

Cable compounds must be flame retardant to achieve a low flame spread, defined by the widely used international cable fire test (lEC 60332-3-24). A combination 

The char of the EVA-ATH-organoclay compound generated by the cone calorimeter was very rigid und showed only very few small cracks but the char of the EVA-ATH compound was much less rigid (lower mechanical strength) and with many big cracks. This could be why for the nanocomposite the PHRR was reduced to 100 kW/m, compared to 200 kW/m for the EVA-ATH compound. To obtain the same decrease for the PHRR by the flame retardant filler ATH only, the content of ATH must be increased to 78 wt% within the EVA-ATH system. 

The great improvements in flame retardancy by the organoclays also opened the possibility of decreasing the level of ATH within the EVA-polymer matrix. To maintain 200 kW/m as a sufficient peak heat release level, the content of ATH could be decreased from 65 wt% to 45 wt% by the presence of only 5 wt% organoclay within the EVA-polymer matrix. The reduction in the total amount of these fillers resulted in improved mechanical and rheological properties of the EVA-based nanocomposite. 

FIGURE 7.4 TGA in air of a compound with 35 wt% EVA and 65 wt% ATH in relation to a nanocomposite compound with 35 wt% EVA, 60 wt% ATH, and 5 wt% of organoclays. EVA, Escorene UL-00328 with 28 wt% vinyl acetate content organoclay, Nanofil 15 ATH, Martinal OL 104 LE. (From Ref. 48, copyright 2001, John Wiley Sons, Ltd., with permission.) 

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