Prepn. of free-flowing and sub-divisible ethylene!-propylene! copolymers and EPDM elastomers - comprises adding solid material insol. in reaction environment to reaction mixt. and maintaining contact of polymer suspension with solid material and recovering polymeric particles

摘要

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 sa 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.