Preparation of flame-retardant PVC foam modified by nitrile rubber

Using chemical crosslinking technology and one-step compression molding process, the foaming technique of flame-retardant polyvinyl chloride (PVC) foamed plastics modified by nitrile rubber (NBR) was studied. The effects of chlorinated paraffin (CP), dioctyl phthalate (DOP), Sb₂O₃, modified rubber types, blowing agents, fillers and crosslinking agent on modified flame-retardant PVC foam were discussed. The optimum recipe (phr) was as follow: PVC 100, NBR 60, DOP 30, CP 30, Sb₂O₃ 8, blowing agent AC 4.0, blowing agent H 4.0, dicamyl peroxide 1.0. The oxygen index of flame-retardant PVC foam was 27.0% and the mechanical properties were good. The experiment of electron microscope showed that the cellular structure of flame-retardant PVC foamed plastics was not so good as that of flammable PVC foamed plastics.