Conjugated diene polymerisation
First Claim
1. 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).
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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.
31 Citations
22 Claims
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1. 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:
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(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). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 22)
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- 13. 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.
Specification