Process for making alpha-olefin polymers or copolymers with high isotacticity index
AssigneeAto Chimie
InventorGilbert Marie
Life of this patent
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Abstract
A process for making crystalline polymers or copolymers of alpha-olefins containing 3 to 8 carbon atoms, such as polypropylene, by polymerization with a catalyst consisting of a combination of titanium chloride and an organic aluminum compound, in the presence of a stereospecificity additive. This stereospecificity additive has the formula: R.sub.1 --O--(C.sub.p H.sub.2p)--S--R.sub.2, where: R.sub.1 and R.sub.2 are alkyl radicals containing 1 to 4 carbon atoms or are linked together to form a divalent --(C.sub.m H.sub.2m)--radical, and p and m are integers each with a value of 1 to 6; this additive may be used in the presence of an activator.
Claims29
In a process for producing polymers or copolymers of alpha-olefins containing from 3 to 8 carbon atoms with a high isotacticity index, by homopolymerization of an alpha-olefin containing 3 to 8 carbon atoms, sequence copolymerization of such alpha-olefins with one another and/or with ethylene, or copolymerization of mixtures of such alpha-olefins with one another and/or with ethylene, such mixtures containing at least 85 moles percent of one such alpha-olefin, using a catalyst containing a titanium chloride and an organic aluminum compound, in the presence of a stereospecificity additive, the improvement which comprises using as the stereospecificity additive a compound of the formula:
- R.sub.1 --O--(C.sub.p H.sub.2p)--S--R.sub.2,
- where:
- p is an integer from 1 to 6,
- R.sub.1 and R.sub.2 are identical or different alkyl radicals containing 1 to 4 carbon atoms, or are linked together to form a divalent--(C.sub.m H.sub.2m)--radical,
- where:
- m is an integer from 1 to 6.
Dependencies are inferred from the claim text.