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US 6,555,631 B1Granted
Manufacture of polyethylenes
AssigneeE. I. Du Pont de Nemours and Company
InventorsLin Wang, Maria Spinu, Joel David Citron
Life of this patent
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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.
Claims20
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;
- wherein each of the oligomerization catalyst, the first polymerization catalyst and the second polymerization catalyst is chemically distinct from the other two.
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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, and wherein said alpha-olefins have an average degree of polymerization of 30 or less;
- (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;
- wherein the oligomerization catalyst is chemically distinct from each of the first and second polymerization catalysts.
2 more elements
Dependencies are inferred from the claim text.