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US 4,786,688 AGranted
Polyethylene composition for extrusion, particularly for blow moulding
AssigneeBP Chimie
InventorsJean P. Thiersault, Daniel Durand, Alain Senez
Life of this patent
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Abstract
The invention concerns polyethylene compositions particularly adapted for the manufacture of film and hollow bodies by blow-moulding, characterized in that they contain (a) from 50 to 98% by weight of polyethylene of high density, of at least 0.940 (b) from 2 to 50% by weight of a linear, low density polyethylene, with a density below 0.930.
Claims6
Polyethylene compositions, characterised in that they contain:
- (a) from 80 to 98% by weight of high density polyethylene having a density of at least 0.940, a melt index measured at 190.degree. C. under a load of 5 kg (MI.sub.5) of 1.2 g/10 minutes or less, and a melt flow ratio defined by the ratio of MI.sub.5 to a melt index measured at 190.degree. C. under a load of 2.16 kg, of 6 or higher,
- (b) from 2 to 20% by weight of linear low density polyethylene, of a density below 0.930 and a melt index of at least one-fourth the melt index of the high density polyethylene which is formed by copolymerizing 85 to 95% by weight ethylene with 15 to 5% by weight of one or more C.sub.3 -C.sub.8 alpha-olefins, in the gaseous phase at a pressure below 4.times.10.sup.6 Pa in the presence of a catalyst containing compound of a transition metal selected from the sub-groups IVa, Va and VIa of the Periodic Table,
- wherein the compositions have a melt index measured at 190.degree. under a load of 2.16 kg of 0.12 g/10 min or higher.
A polyethylene composition comprising:
- (a) from 80 to 98% by weight of high density polyethylene having a density of at least 0.940, a melt index measured at 190.degree. C. under load of 5 kg (MI.sub.5) of 1.2 g/10 minutes or less, and a melt flow ratio defined by the ratio of MI.sub.5 to a melt index measured at 190.degree. C. under a load of 2.16 kg, of 6 or higher,
- (b) from 2 to 20% by weight of linear low density polyethylene, of a density below 0.930 and a melt index of at least one-fourth the melt index of the high density polyethylene and which is formed by copolymerizing 85 to 95% by weight ethylene with 15 to 5% by weight of an alpha-olefin selected from the group consisting of propylene and 1-n-butene in the gaseous phase in a fluidized bed at a pressure below 4.times.10.sup.6 Pa in the presence of a catalyst containing compound of a transition metal selected from the subgroups IVa, Va and VIa of the Periodic Table,
- wherein the compositions have a melt index measured at 190.degree. C. under a load of 2.16 kg of 0.12 g/10 min or higher.
Polyethylene compositions consisting essentially of:
- (a) from 80 to 98% by weight of high density polyethylene having a density of at least 0.940, a melt index measured at 190.degree. C. under a load of 5 kg (MI.sub.5) of 1.2 g/10 minutes or less, and a melt flow ratio defined by the ratio of MI.sub.5 to a melt index measured at 190.degree. C. under a load of 2.16 kg, of 6 or higher,
- (b) from 2 to 20% by weight of linear low density polyethylene, of a density below 0.930 and a melt index of at least one-fourth the melt index of the high density polyethylene and which is formed by copolymerizing 85 to 95% by weight ethylene with 15 to 5% by weight of one or more C.sub.3 -C.sub.8 alpha-olefins in the gaseous phase in a fluidized bed at a pressure below 4.times.10.sup.6 Pa in the presence of a catalyst containing compound of a transition metal selected from the subgroups IVa, Va, and VIa of the Periodic Table,
- wherein the compositions have a melt index measured at 190.degree. C. under a load of 2.16 kg of 0.12 g/10 minutes or higher.
Dependencies are inferred from the claim text.