| 摘要 |
A process for the in situ blending of polymers comprising continuously contacting, under polymerization conditions, a mixture of ethylene and at least one alpha-olefin having at least 3 carbon atoms with a catalyst in at least two fluidized bed reactors connected in series, said catalyst comprising: (i) a complex consisting essentially of magnesium titanium, a halogen, and an electron donor; (ii) at least one activator compound for the complex having the formula AlR''eX'fHg wherein X' is Cl or OR'''; R'' and R''' are saturated aliphatic hydrocarbon radicals having 1 to 14 carbon atoms and are alike or different; f is 0 to 1.5; g is 0 or 1; and e+f+g=3; and (iii) a hydrocarbyl aluminum cocatalyst, the polmerization conditions being such that ethylene copolymer having a high melt index in the range of about 0.1 to about 1000 grams per 10 minutes is formed in at least one reactor and ethylene copolymer having a low melt index in the range of about 0.001 to about 1.0 gram per 10 minutes is formed in at least one other reactor, each copolymer having a density of about 0.860 to about 0.965 gram per cubic centimeter and a melt flow ratio in the range of about 22 to about 70, and being admixed with active catalyst.
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