Conjugated diene polymerisation
AssigneeEnichem Elastomers Limited
InventorsPeter John Ansell, Hugh David Williams
Life of this patent
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Abstract
A process for the polymerization of one or more conjugated dienes by means of a rare earth based catalyst in which the catalyst is formed by bringing together in liquid hydrocarbon medium in the presence of a small portion of conjugated diene: a) a rare earth salt, b) an organo aluminum and c) a silicon halide or organosilicon halide and aging the catalyst before contact with the conjugated diene(s) to be polymerized. This catalyst formation procedure offers the possibility of producing a diene polymer of high cis content with a narrower molecular weight distribution and/or smaller high molecular weight fraction which is reflected in improved processing characteristics and reduced viscosity in styrene.
Claims22
A process for the catalytic polymerization of at least one conjugated diene by a catalyst comprising a rare earth salt, an organo aluminium cocatalyst and a source of halogen, said process comprising the steps of:
- (a) preparing said catalyst by bringing together, in a liquid hydrocarbon medium and in the presence of a portion of at least one conjugated diene (i) a rare earth salt, (ii) an organo aluminium compound and (iii) as the source of halogen, a silicon halide or organosilicon halide:
- (b) aging said catalyst;
- and
- (c) polymerizing at least one conjugated diene in the presence of the catalyst of step (b).
A catalyst useful in the catalytic polymerization of at least one conjugated diene comprising a rare earth salt, an organo aluminium cocatalyst and a source of halogen, said catalyst being prepared by bringing together, in a liquid hydrocarbon medium and in the presence of a portion of at least one conjugated diene, (i) a rare earth salt, (ii) an organo aluminium compound and (iii) as the source of halogen, a silicon halide or organosilicon halide, and aging said catalyst.
Dependencies are inferred from the claim text.