Ethylene copolymer for biaxial orientation
AssigneeNOVA Chemicals (International) S.A.
InventorsMaryam Fereydoon, Shivendra Goyal, Stephen Brown, Owen Lightbody, Norman Aubee, Bronwyn Gillon, Thomas Green, Lison Mark, Christian Carello
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Abstract
An ethylene copolymer comprising ethylene and at least one alpha olefin having from 4 to 8 carbon atoms has a density f from 0.940 to 0.960 g/cm3, a molecular weight distribution, Mw/Mn of from 9 to 12, and a Z-average molecular weight, Mz of greater than 500,000. The ethylene copolymer is made in a multi-zone reactor system under solution phase polymerization conditions and is useful in the preparation of biaxially oriented polyethylene (BOPE) films.
Claims23
An ethylene copolymer comprising ethylene and at least one alpha olefin having from 4 to 8 carbon atoms;
- wherein the ethylene copolymer has a density of 0.940 to 0.960 grams per cubic centimeter (g/cm3);
- a melt index, I2 as measured by ASTM D1238 at 190° C. using a 2.16 kilogram load, of from 0.5 to 2.5 grams per 10 minutes (g/10 min);
- a stress exponent of from 1.75 to 1.95;
- a number average molecular weight, Mn, of from 11,000 to 15,000;
- a polydispersity index, (Mw/Mn), of from 9 to 12;
- and a Z-average molecular weight, Mz, of from 500,000 to 800,000.
A solution phase polymerization process to make an ethylene copolymer in a multi-zone reactor system,
- the multi-zone-reactor system comprising a first, second and third polymerization zone, wherein the first polymerization zone is defined by a first tubular reactor having an inlet and an outlet,
- the polymerization process comprising:
- feeding solvent, hydrogen, a Ziegler-Natta polymerization catalyst, ethylene, and at least one alpha olefin having 4 to 8 carbon atoms, to the inlet of the first tubular reactor to initiate a polymerization reaction;
- feeding hydrogen to at least one location in the first tubular reactor which is downstream from the inlet of the first tubular reactor;
- wherein at least 80 weight percent of a total amount of hydrogen added to the multi-zone reactor system, is added to the at least one location in the first tubular reactor which is downstream from the inlet of the first tubular reactor;
- and
- wherein from 20 to 50 weight percent of a total amount of ethylene copolymer made in the multi-zone reactor system is made in the first tubular reactor.
A solution phase polymerization process to make an ethylene copolymer in a multi-zone reactor system,
- the multi-zone reactor system comprising a first, second and third polymerization zone, wherein the first polymerization zone is defined by a first tubular reactor having an inlet and an outlet,
- the polymerization process comprising:
- feeding solvent, hydrogen, a Ziegler-Natta polymerization catalyst, ethylene, and at least one alpha olefin having 4 to 8 carbon atoms, to an inlet of the first tubular reactor to initiate a polymerization reaction;
- feeding hydrogen to at least one location in the first tubular reactor which is downstream from the inlet of the first tubular reactor;
- wherein at least 80 weight percent of a total amount of hydrogen added to the multi-zone reactor system, is added to at least one location in the first tubular reactor which is downstream from the inlet of the first tubular reactor;
- and wherein
- the ethylene copolymer has a density of 0.940 to 0.960 grams per cubic centimeter (g/cm3);
- a melt index, I2as measured by ASTM D1238 at 190° C. using a 2.16 kilogram load, of from 0.5 to 2.5 grams per 10 minutes (g/10 min);
- a stress exponent of from 1.75 to 1.95;
- a number average molecular weight, Mn, of from 11,000 to 15,000;
- a polydispersity index, (Mw/Mn), of from 9 to 12;
- and a Z-average molecular weight, Mz, of from 500,000 to 800,000.
A biaxially oriented polyethylene film comprising an ethylene copolymer, the ethylene copolymer comprising ethylene and at least one alpha olefin having from 4 to 8 carbon atoms;
- wherein the ethylene copolymer has a density of 0.940 to 0.960 grams per cubic centimeter (g/cm3);
- a melt index, I2 as measured by ASTM D1238 at 190° C. using a 2.16 kilogram load, of from 0.5 to 2.5 grams per 10 minutes (g/10 min);
- a stress exponent of from 1.75 to 1.95;
- a number average molecular weight, Mn, of from 11,000 to 15,000;
- a polydispersity index, (Mw/Mn), of from 9 to 12;
- and a Z-average molecular weight, Mz, of from 500,000 to 800,000.
Dependencies are inferred from the claim text.