Use of a ziegler-natta catalyst to make a polypropylene hompolymer or random copolymer having a high melt flow rate
AssigneeTotal Petrochemicals Research Feluy
InventorsValerie Terreur, Jerome Gromada
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Abstract
The present invention relates to a process for the production of a high melt flow propylene homopolymer or random copolymer with low odor and low volatiles content, which is suitable for thin-walled injection molding applications, said process comprising the step of polymerizing propylene and one or more optional comonomers in presence of a Ziegler-Natta catalyst comprising a titanium compound having at least one titanium-halogen bond, and a diether compound as internal electron donor, both supported on a magnesium halide in active form, an organoaluminium compound and an optional external donor.
Claims20
A process for the production of propylene polymers having a melt flow index ranging from 45 to 150 dg/min (ASTM D 1238 condition L) directly in a polymerization reactor without the subsequent use of melt flow increasing agents, said process comprising the step of polymerizing propylene and one or more comonomers in presence of
- a Ziegler-Natta catalyst comprising a titanium compound having at least one titanium-halogen bond, and a diether compound as internal electron donor, both supported on a magnesium halide in active form,
- an organoaluminium compound in such an amount that the aluminium concentration, by weight relative to the added monomer, in the polymerization medium ranges from 1 to 75 ppm,
- an external electron donor, and
- hydrogen,
- wherein the molar ratio of organoaluminium compound to external electron donor ranges from 1 to 20.
A process for producing an article comprising the steps of
- (a) producing a propylene polymer having a melt flow index ranging from 45 to 150 dg/min (ASTM D 1238 condition L) directly in a polymerization reactor without the subsequent use of melt flow increasing agents, said process comprising the step of polymerizing propylene and one or more comonomers in presence of a
- a Ziegler-Natta catalyst comprising a titanium compound having at least one titanium-halogen bond, and a diether compound as internal electron donor, both supported on a magnesium halide in active form,
- an organoaluminium compound in such an amount that the aluminium concentration, by weight relative to the added monomer(s), in the polymerization medium ranges from 1 to 75 ppm,
- an external electron donor, and
- hydrogen,
- wherein the molar ratio of organoaluminium compound to external electron donor ranges from 1 to 20,
- (b) recovering a propylene polymer having a melt flow index ranging from 45 to 150 dg/min (ASTM D 1238 condition L) directly from the polymerization reactor without the subsequent use of melt flow increasing agents, and
- (c) transforming the polymer to make an article.
Dependencies are inferred from the claim text.