US 4,536,550 AGranted

Polyethylene composition

AssigneeAsahi Kasei Kogyo Kabushiki Kaisha

InventorsKisoo Moriguchi, Tadashi Ikegami

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Abstract

A polyethylene composition comprising three specific types of polyethylenes; polyethylene (A), polyethylene (B) and polyethylene (C) respectively. The polyethylene composition has a melt index not less than 0.001 g/10 min. and not more than 10 g/cm and exhibits excellent processability under variant molding techniques. Molded objects exhibit excellent physical properties such as impact strength environmental stress cracking resistance and uniform thickness distribution. Polyethylene (A) has a molecular weight of from 5,000 to 90,000 and polyethylene (C) has a molecular weight of from 100,000 to 1,500,000 and the ratio of the molecular weight of polyethylene (C)/the molecular weight of polyethylene (A) is from 4 to 200. Polyethylene (B) has a molecular weight of from 50,000 to 500,000, being prepared by a polymerization with use of a chromium compound-supported type catalyst capable of producing a specifically conditioned homopolyethylene with respect to the properties of the polymers in terms of flow ratio and die swell.

Claims8

Dependent claims

A polyethylene composition comprising three types of polyethylene (A), (B) and (C) selected from the group consisting of homopolymers of ehtylene and copolymers of ethylene and an .alpha.-olefin, wherein

(i) the polyethylene (A) has a molecular weight of from 5,000 to 90,000, the polyethylene (C) having a molecular weight of from 100,000 to 1,500,000 and the ratio of the molecular weight of the polyethylene (C)/ the molecular weight of polyethylene (A) being between 4 and 200, and the polyethylene (A) and the polyethylene (C) are produced by a polymerization using a magnesium-containing Ziegler type catalyst,
(ii) the polyethylene (B) has a molecular weight of from 50,000 to 500,000 produced by a polymerization using a chromium compound supported type catalyst capable of producing a homopolymer of ethylene in a single stage polymerization having a flow ratio of from 40 to 150 and a die swell of from 40 to 100 g/20 cm measured at the condition in which the said homopolymer exhibits a melt index of 1 g/10 min.,
(iii) the ratio of the polyethylene (A) and the polyethylene (C) by weight is from 70 to 30 to 30 to 70, and the amount of the polyethylene (B) in the composition ranges from 10% by weight to 75% by weight, and
(iv) the melt index of the composition is not less than 0.001 g/10 min., and not more than 10 g/100 min.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 06/599,401Filed 12 Apr 1984
Priority: JP 58-6919521 Apr 1983
Granted: 20 Aug 1985
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

C08L 23/06
Homopolymers or copolymers of ethene: polyethylene
C08L 23/0815
With unsaturated hydrocarbons only containing four or more carbon atoms: with aliphatic 1-olefins containing one carbon-to-carbon double bond
C08L 2205/02
Polymer mixtures characterised by other features: containing two or more polymers of the same C08L -group
C08L 2205/025
Containing two or more polymers of the same C08L -group: containing two or more polymers of the same hierarchy C08L, and differing only in…