Ethylene-propylene elastomeric copolymers with a low content of residual chlorine
AssigneeEnichem Elastomeri S.r.l.
InventorsTiziano Tanaglia, Viviano Banzi, Elisa Zecchi
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Abstract
In an improved process for producing elastomeric ethylene-propylene copolymers with a propylene content comprised within the range of from 22 to 38% by weight and a content of residual chlorine, coming from the co-catalyst, lower than 300 parts per million parts, the polymerization is carried out in suspension in the monomers in the liquid state, with vanadium triacetylacetonate and alkyl-Al compounds, and the obtained polymer is recovered without any washing steps.
Claims6
A process for preparing ethylene copolymers with alpha-C.sub.3 -C.sub.10 -olefins, operating with the copolymer in suspension in the mixture of monomers in the liquid state, wherein
- (a) the molar ratio of alpha-C.sub.3 -C.sub.10 -olefin(s) to ethylene in liquid phase is comprised within the range of from 7 to 15,
- (b) the polymerization is carried out in the presence of a catalytic system comprising:
- (i) an organic compound of vanadium, which does not contain chlorine,
- (ii) a mixture of at least one alkyl-Al compound with at least one chloro alkyl-Al, such that the atomic ratio of Cl/Al is lower than, or equal to, 0.5,
- (iii) a chlorinated ester,
- with the molar ratio of (iii)/(i) being comprised within the range of from 1 to 10;
- wherein said polymerization affords a copolymer with a content of chloride from metal-organic catalytic residues lower than 300 ppm.
Dependencies are inferred from the claim text.