烷氧基镁制备的乙烯淤浆聚合用催化剂

Preparation of catalyst for ethylene slurry polymerization based on magnesium alkoxide

以烷氧基镁为原料,采用溶解析出法在甲苯中与环氧氯丙烷、硅酸乙酯反应制备了用于乙烯淤浆聚合用催化剂,利用SEM、粒径分布分析等方法研究了制备条件对催化剂性能的影响。实验结果表明,催化剂适宜的制备条件为n(烷氧基镁)∶n(硅酸乙酯)∶n(环氧氯丙烷)=1∶1.71∶4.87、熟化温度85℃、甲苯用量80 mL、TiCl_(4)用量25 mL。该条件下制备的催化剂用于乙烯淤浆聚合时,活性可达30.50 kg/g,所得聚乙烯堆密度为0.34 g/cm^(3),平均粒径为13.32μm,熔体流动指数(10min)为1.089 g。该催化剂适用于乙烯淤浆聚合工艺生产高性能聚乙烯产品。

Ethylene slurry polymerization catalyst was prepared by solution precipitation method with magnesium alkoxide as raw material reacting with epichlorohydrin and ethyl silicate using toluene as solvent.The catalysts were characterized by SEM and laser particle size analyzer.The effect of preparation condition on ethylene slurry polymerization was further investigated.The results show that the optimum conditions for preparing catalyst were n(magnesium alkoxide)∶n(tetraethoxysilane)∶n(epoxy chloropropane)1∶1.71∶4.87,85℃,toluene 80 mL,TiCl^(4) 25 mL.The catalyst prepared under the optimum conditions shows activity about 30.50 kg/g.The bulk density,average particle size and melt index(10 min)of polyethylene is 0.34 g/cm^(3),13.32μm,1.089 g,respectively.The catalytic performance indicates that the catalyst prepared hereby is quite capable for ethylene slurry polymerization process to develop high-quality polyethylene products.