新型氧化铬型聚乙烯催化剂的研究

Study on New Type of Chromium Oxide Catalyst for Polyethylene

研究了钛化合物改性的新型氧化铬型催化剂及其制备方法,以及铬的质量分数、钛的质量分数和煅烧活化温度对催化剂性能的影响。研究结果表明：采用铬、钛活性组分分别负载,以一定比例混合活化的新方法明显提高了钛化合物的改性效率,相对分子质量调节能力更好,聚合物的相对分子质量分布更宽。工业化应用试验表明：新型氧化铬型催化剂能够在气相冷凝态工艺上稳定运行,聚合效率达到6 000g PE/g cat,聚合物的相对分子质量分布达到17~18。通过工艺条件的调控,可以生产如薄膜和大型中空容器等相对分子质量分布很宽的聚乙烯专用料。

A new type of composite CrO_3 catalyst improved by titanium compound and its preparation,and the effects of mass fraction of chromium,titanium and activation temperature on the properties of the catalysts were studied.The results show that the catalysts prepared by the new method that the chromium and titanium component are impregnated on silica respectively and then they are mixed in a certain proportion to activate together have greater relative molecular mass regulation ability than normal method,and the PE also has wider relative molecular mass distribution than normal method.The industrial tests indicate that the new type of CrO_3 catalyst can be used in the gas phase condensation technology.The polymerization efficiency reaches 6 000 g PE/g cat and the relative molecular mass distribution of the polymer reaches 17-18.And by controlling the technological conditions,it can be used to produce varied special PE grades such as films and large hollow container.