| 摘要 |
<p>A supported catalyst for polymerizing 1-olefins, for example, ethylene, is prepared by depositing a chromium compound and a titanium compound on a refractory oxide support which is substantially non-spherical, and which has a relatively broad particle size distribution range. The catalyst is preferably combined, either outside of the polymerization vessel or in situ, with a sufficient amount of at least one magnesium composition of the formula RMgR min , where R and R min are the same or different and they are C1 to C12 hydrocarbyl groups, to provide a molar ratio of magnesium to chromium in the catalyst composition in excess of 1.25:1 to 25:1. The resulting catalyst composition has good feedability and fluidization characteristics, and it produces resins of relatively high HLMI at relatively low temperatures. There is also disclosed a process for polymerizing 1-olefins, at relatively lower temperatures than was heretofore possible, to obtain resins of relatively high HLMI, using the above-identified catalyst composition. The resulting polymers can be used for the fabrication of blow-molded products, e.g., household and industrial containers.</p> |
