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.
Claims25
A process for producing a blend of two or more polyethylenes, comprising the step of contacting:
- (1) ethylene;
- (2) an active ethylene oligomerization catalyst under conditions to oligomerize at least a portion of the ethylene to one or more α-olefins of the general formula R18CH═CH2, wherein R18 is alkyl containing an even number of carbon atoms;
- (3) a first active polymerization catalyst under conditions to copolymerize ethylene and the α-olefins generated from the active ethylene oligomerization catalyst;
- and
- (4) a second active polymerization catalyst under conditions to polymerize ethylene, but not readily copolymerize ethylene and α-olefins.
A polymerization catalyst component, comprising:
- (a) an oligomerization catalyst that oligomerizes ethylene to one or more α-olefins of the formula H2C═CHR18, wherein R18 is an alkyl containing an even number of carbon atoms;
- (b) a first polymerization catalyst that is capable of copolymerizing ethylene and one or more α-olefins of the formula H2C═CHR18;
- and
- (c) a second polymerization catalyst chemically distinct from the first polymerization catalyst, that is capable of polymerizing ethylene but does not readily copolymerize ethylene and α-olefins.
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
- (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, 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.