磷元素对汽车内饰用模具硅橡胶硫化行为的影响

Effect of Phosphorus on Vulcanization Behavior of Silicone Rubber for Automobile Interior Decoration

针对汽车内饰用模具硅橡胶出现的硫化不充分问题,通过向双组分室温硫化(RTV-2)加成型液体硅橡胶中加入一定量的三(2,4-二叔丁基苯基)亚磷酸酯与磷酸三苯酯,研究了不同价态磷(P)元素对硅橡胶硫化行为的影响以及引起铂催化剂中毒的临界P元素含量.结果表明,聚氯乙烯(PVC)表皮中引起硅橡胶不完全硫化的主要因素为不饱和态的P元素.不饱和态P元素轨道上的共享电子对会与铂结合,发生不可逆反应,引起铂催化剂中毒,从而导致RTV-2硅橡胶无法完全硫化.在实际生产中,需保证PVC表皮中不饱和P元素含量小于导致铂催化剂中铂元素中毒的临界值,RTV-2硅橡胶方可完全硫化,复制出清晰的PVC表皮花纹.

In order to solve the problem of insufficient vulcanization of the molding silicone rubber used in automobile interior decoration,a certain amount of tri-( 2,4-bis-tert-butyl phenyl) phosphite( A) and triphenyl phosphate ester( B) were added into RTV-2( two-component room temperature vulcanized) liquid silicone rubber. The influence of different valence state phosphorus( P) on the vulcanization behavior of silicone rubber and the critical content of P for platinum catalyst poisoning were studied. The results show that the main reason which causing the non-vulcanization of silicone rubber in the polyvinyl chloride( PVC) skin is because of the unsaturated P element. The shared electron pairs on the orbit of the unsaturated phosphorus element will combine with platinum,causing an irreversible reaction,and lead to the poisoning of the platinum catalyst,resulting in the incomplete vulcanization of RTV-2 silicone rubber. In the practical production,it is necessary to ensure that the content of unsaturated P element in PVC skin is less than the critical value which causes platinum element poisoning in platinum catalyst,and the RTV-2 silicone rubber can be completely vulcanized to replicate clear PVC skin pattern.