| 摘要 |
Methods of making polymers from polymerizable 1-olefins which comprise polymerizing at least one 1-olefin with a catalyst system consisting essentially of a mixture of (1) a support which is a finely divided insoluble inorganic support material such as silica, alumina, zirconia or thoria or mixtures thereof containing titanium, zirconium or nickel prepared by fluidizing the finely divided support in the form of a bed with a substantially dry gas while adding to the bed at an elevated temperature, while fluidizing, a compound of the class consisting of titanium or zirconium or nickel esters, or halides or mixtures thereof which were further calcined at a higher temperature and (2) an organotin chromate containing the group essentially of the formula O PARALLEL R3Sn-O-Cr-O-SnR3 PARALLEL O and (3) cocatalytic amounts of an alkyl aluminum compound of the formula RaAlXb in each of which formula R is a hydrocarbon radical containing from 1 to about 14 carbon atoms, X is hydrogen, halogen or alkoxy, a is an integer of 1 to 3, b is an integer of 0 to 2 and the sum of a and b is 3, the system having an aluminum-chromium ratio of at least 2 to 1.
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