| 摘要 |
<p>ADDITIVE-CONTAINING POLYOLEFIN BEADS AND PROCESS FOR THEIR PREPARATION The invention provides an additive-containing polyolefin having an inner bead of a first polyolefin and an outer adherant coating of a second polyolefin encapsulating the additive. BACKGROUND OF THE INVENTION Recently new catalysts have been developed which are far more active than conventional catalysts in the polymerization of alpha-olefins. Briefly described, these catalysts are comprised of a titanium halide catalyst component supported on magnesium dihalide and an alkylaluminum compound, which can be present as a complex with an electron donor compound. These catalyst components have been described in the patent literature, e.g., in U.S. Pat. Nos. 3,830,787, 3,953,414, 4,051,313, 4,115,319, 4,149,990, 4,218,339, 4,220,554, 4,226,741 and 4,263,169 Catalysts of these types function well in the homo and copolymerization of alpha-olefins having from 2 to 18 carbon atoms particularly when the process is carried out under slurry conditions using a liquid hydrocarbon diluent, which can be liquid monomer, inert hydrocarbon or a mixture of such compounds. The productivities obtained with these new catalysts are extremely high resulting in polymers containing such small quantities of residual catalyst that the conventional deashing step can be dispensed with. Further improvements in overall process economics have been achieved by the use of spherical or spheroidal-shaped supported titanium halide catalyst compounds in slurry polymerizations of</p> |
