Study On Preparing High Fire-retardant PVC Cable Materials And Application

The symmetrical category cables have the fastest growth among all the cables. Whilethe cables provide convenience to society, they also bring the fire risk. The cables may belighted by internal and external causes, and then they flame along the direction of thecablse to all over the building. If they ignite other things, they can may cause dangerousfire. When the cables are ignited, they will release large amount of toxic gases and heavysmoke, which can harm people, even make people dead. Because people’s safetyconsciousness raises more and more highly, they also need more fire retardant cable. Theflame retardant property of the cables depends on its cover materials. So the high flameretardant cable materials are the key to the flame retardant cables. PVC、polyolfiin、rubberare commonly used as cable’s cover materials. In order to achieve high flame retardancy,lots of fire retardants must be added into polyolfin、rubber. which cause the mechanicalproperties and electrical properties reduce greatly. Because of the PVC’s good flameresistance and low price, PVC is the good materials to produce the high flame retardantcables.In this paper, we firstly use PVC system filled with hydroxide to study how differentcontents of antimony trioxide、zinc borate、zinc stannate、ammoinum octamolybdate、nanoclay and bis(2-ethylhexyl) tetrabromophthalate effect materails’ flame resistant and otherproperties respectively. Antimony trioxide、zinc borate、Zinc stannate、ammoinumoctamolybdate and nano clay have few influence on the tensile strength, elongation,hardness and other mechanical properties. Effect on the oxygen index is antimonytrioxide、Zinc stannate＞ammoinum octamolybdate＞zinc borate、nano clay. The smokesuppression of ammoinum octamolybdate is best. The smoke suppression of zinc borateand zinc stannate is second. The addition of nanoclay has little effect on the amount ofsmoke. The addition of antimony trioxide makes large amount of smoke.Then this paperstudies synergistic effects of several fire retardant（antimony trioxide、zinc borate、Zinc stannate、ammoinum octamolybdate、nano clay） in the orthogonal design method.Antimony trioxide has the most significant effect to limit oxygen index. The degree ofinfluence on the oxygen index is antimony trioxide＞zinc borate＞zinc stannate＞nanoclay.＞ammoinum octamolybdate. The order is different from the order when the aboveflame retardant is used alone. Two kind of flame retardants(zinc borate、nano clay) are usedmainly as the synergistic flame retardant. According to the results of orthogonal design, wedefine the two formulas of CMR and CMP flame retardant PVC cable materials, and thentest the performances. The performances are better than or same as the performances in thereferences.Using twin-screw double order extrusion unit, we verify the two formulas of CMRand CMP flame retardant PVC cable materiasl, and find the processing performance isgood. The performances are better than or same as the expectation. The two flame retardantPVC cable materials are used as the jecket of UTP5category cables. Two kinds of cablescan pass CMR or CMP burning test.