Study On Flame Retardancy Of NBR/PVC Foaming Elastomer

NBR/PVC foaming material has been widely used because of its low density, small thermal conductivity, softness and good buffer, compression performance, oil resistance, chemical resistance, plasticity, weather resistance, thermal insulation, etc. But its bad flame retardancy restricted its application in some occasions. This paper studied the effects of curing system, ratio of rubber and plastics, content of foaming agent AC on the NBR/PVC foaming properties, and the optimum formula was obtained. The effects of DBDPE and its flame retardant synergistic agent, Mg(OH)2, ZB, IFR(APP/PER) flame retardant agent and their complex flame retardant system on NBR/PVC foaming and flame retardant properties by the scanning electron microscope (SEM), the limiting oxygen index instrument (LOI), vertical burning tester (UL-94), smoke density instrument and thermal weight analysis instrument (TG). The results showed that:1. The effect of formula on NBR/PVC foaming material were studied. In the low sulfur and high promotion system, when NBR/PVC rubber plastic ratio was50/50, foaming agent AC amount was12phr, the bubble of NBR/PVC foaming material were closed and distributed uniformly, and the comprehensive mechanical properties of NBR/PVC foaming material were best.2. The effect of halogen flame retardant system on NBR/PVC foaming material were studied. Synergistic effect of DBDPE and Sb2O3was the best. When the amout of DBDPE/Sb2O3was27/9, the oxygen index could reach32%, but Sb2O3could significantly increase the smoke density of NBR/PVC foaming material. APP and ZB also had synergistic effect with DBDPE, so they could replace part of Sb2O3. ZRQW2did not have synergistic effect with DBDPE. APP, ZB and ZRQW2could reduce the smoke density of NBR/PVC foam, and the smoke suppression ability was ZRQW2>ZB>APP. 3. The effect of low smoke and low halogen flame retardant system on NBR/PVC foaming material were studied. With the increasing of Mg(OH)2, the oxygen index,density, and the bubble size of NBR/PVC foaming material increased,but the mechanical properties increased firstly and then decreased.The increase of APP:PER ratio could reduce the density, mechanical strength and LOI of the NBR/PVC foaming material, but it could increase the bubble size. With the increasing of ZB, the density and mechanical properties of NBR/PVC foaming material decreased, and the bubble size increased, but the LOI increased firstly and then decreased. The smoke suppression ability of DBDPE/Sb2O3, Mg(OH)2,ZB,and APP/PER complex flame retardant system was Mg(OH)2/IFR> DBDPE/Sb2O3/Mg(OH)2/ZB/IFR>DBDPE/Sb2O3/Mg(OH)2/IFR> DBDPE/Sb2O3/Mg(OH)2. DBDPE/Sb2O3, Mg(OH)2, ZB and APP/PER complex flame retardant could promote each other into carbon, which increased the carbon content, and improved the stability and flame retardant properties of NBR/PVC foam.