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US 6,921,795 B2Granted
Manufacture of polyethylenes
AssigneeE.I. du Pont de Nemours and Company
InventorsLin Wang, Maria Spinu, Joel David Citron
Life of this patent
Estimating the term…
Abstract
Blends of two or more polyethylenes are made by reacting ethylene with an oligomerization catalyst that forms α-olefins, and two polymerization catalysts, one of which under the process conditions copolymerizes ethylene and α-olefins, and the other of which under process conditions does not readily copolymerize ethylene and α-olefins. The blends may have improved physical properties and/or processing characteristics.
Claims7
A polymer blend comprising:
- (a) a first polyethylene that contains at least three different branches of the formula —(CH2CH2)nH, wherein n is an integer of 1 or more, and which has less than 2 methyl branches per 1000 methylene groups, and
- (b) a second polyethylene that is different from the first polyethylene, in a weight ratio of about 1:4 to about 4:1 based on the total weight of the first and second polyethylenes, and provided that said second polyethylene has a melting point at least 20° C. higher than said first polyethylene, or said second polyethylene has a heat of fusion at least 50 J/g greater than said first polyethylene, or both.
A polymer blend comprising:
- (a) a third polyethylene having a density of less than 0.93 g/mL, containing at least 2 ethyl branches, at least 2 hexyl or longer branches and at least one butyl branch per 1000 methylene groups, and provided that said third polyethylene has fewer than 5 methyl branches per 1000 methylene groups;
- and
- (b) a fourth polyethylene having a density of 0.93 g/mL or more.
A polymer blend comprising:
- (a) a fifth polyethylene containing about 20 to about 150 branches of the formula —(CH2CH2)nH per 1000 methylene groups, wherein n is an integer of 1 to 100, and at least 2 of said branches per 1000 methylene groups each are ethyl and n-hexyl or longer and at least one of said branches per 1000 methylene groups is n-butyl, provided that said fifth polyethylene has less than about 20 methyl branches per 1000 methylene groups;
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- (b) a sixth polyethylene that is different from the fifth polyethylene and has a density of about 0.93 g/mL or more.
A polymer blend comprising:
- (a) a fifth polyethylene, which is a homopolyethylene, containing about 20 to about 150 branches of the formula (CH2CH2)nH per 1000 methylene groups, wherein n is an integer of 1 to 100, provided that said fifth polyethylene has less than about 20 methyl branches per 1000 methylene groups;
- and
- (b) a sixth polyethylene that is different from the fifth polyethylene and has a density of about 0.93 g/mL or more.
Dependencies are inferred from the claim text.