| 摘要 |
<p>The prepn. of copolymers of ethylene with propylene and opt. another diene in a suspension of liq. monomer in the presence of a catalyst comprising: (a) Ti salt supported on Mg salt; and (b) cpd. of V soluble in hydrocarbon solvents either supported on an inert material or prepolymerised and a co-catalyst consisting of an organic cpd. of Al and a possible chlorinated activator. When polymerisation is almost complete, a solid material insol. in the reaction environment and having an average dia. of 0.001-200 mu m is added to the reaction mixt. The suspension of polymer and solid material are kept in contact for sufficient time to obtain perfectly free-flowing polymeric particles. The perfectly free-flowing polymeric particles are recovered. Pref. the solid material has an average dia. of 0.005-5 mu m and has a surface area of over (more than 40) 10 m2/g and a porosity of more than 20 (more than 80) ml/100 g. The solid material is silica having average dimensions of 0.01-0.025 mu m, a surface area of 130-200 m2/g and a porosity of 200-300 ml/100 g; or C black having average dimensions of 0.015-0.004 mu m, a surface area of 50-100 m2/g and a porosity of 80-120 ml/100 g. The amt. of solid material added to the reaction mixt. is at least 0.05 (0.5-8)%wt. w.r.t. the polymer formed.</p> |
