Polymer film
A film of a polyethylene produced by polymerization catalysed by a single site catalyst and comprising as comonomers to ethylene at least two C 4-12 alpha olefins, preferably but-1-ene and hex-1-ene.
1. A film of a bimodal polyethylene produced by polymerization catalysed by a single site catalyst having more than one η 5 -cyclic ligand said bimodal polyethylene comprising
ai) a lower molecular weight homopolymer of ethylene and
bi) a higher molecular weight terpolymer of ethylene, 1-butene and a C 6 to C 12 alpha-olefin,
or
aii) a lower molecular weight polymer which is a binary copolymer of ethylene and a comonomer selected from C 4 to C 12 alpha-olefins and
bii) a higher molecular weight polymer which is either a binary copolymer of ethylene and 1-butene, if the lower molecular weight polymer of aii) is a binary copolymer of ethylene and a C 6 to C 12 alpha-olefin, or a terpolymer of ethylene, 1-butene and a comonomer selected from C 6 to C 12 alpha-olefin;
wherein all components are made by the same catalyst.
2. A film as claimed in claim 1 wherein the C 6 to C 12 alpha-olefin of part bi) is selected from the group consisting of: hex-1-ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and dec-1-ene.
3. A film as claimed in claim 1 wherein the comonomer of part aii) is selected from the group consisting of: but-1-ene and hex-1-ene.
4. A film as claimed in claim 1 wherein the lower molecular weight component constitutes from 30 to 70% wt of the polyethylene.
5. A film as claimed in claim 1 wherein the comonomer content of said polyethylene is 0.1 to 10% mol.
6. A film as claimed in claim 1 wherein the density of said polyethylene is from 905 to 930 kg/m 3 .
7. A film as claimed in claim 1 wherein the weight average molecular weight of said polyethylene is 50000 to 250000 g/mol.
8. A film as claimed in claim 1 wherein the molecular weight distribution of said polyethylene is from 3 to 8.
9. A film as claimed in claim 1 wherein the MFR 2 of said polyethylene is 0.4 to 3 g/10 min.
10. A film as claimed in claim 1 wherein said polyethylene is blended with a further polymer.
11. A film as claimed in claim 10 wherein said further polymer is a low density polyethylene (LDPE).
12. A film as claimed in claim 1 comprising a plurality of layers.
13. A film as claimed in claim 1 produced by extrusion using a blow up ratio of from 2:1 to 4:1.
14. A film as claimed in claim 1 wherein said bimodal polyethylene comprises
aii) a lower molecular weight polymer which is a binary copolymer of ethylene and a comonomer selected from C 4 to C 12 alpha-olefin and
bii) a higher molecular weight polymer which is either a binary copolymer of ethylene and 1-butene, if the lower molecular weight polymer of aii) is a binary copolymer of ethylene and a C 6 to C 12 alpha-olefin, or a terpolymer of ethylene, 1-butene and a comonomer selected from C 6 to C 12 alpha-olefin.
15. A polyethylene composition for film production, said composition comprising a bimodal polyethylene produced by polymerization catalysed by a single site catalyst having more than one η 5 -cyclic ligand comprising
ai) a lower molecular weight homopolymer of ethylene and
bi) a higher molecular weight terpolymer of ethylene, 1-butene and a C 6 to C 12 alpha-olefin,
or
aii) a lower molecular weight polymer which is a binary copolymer of ethylene and a comonomer selected from C 4 to C 12 alpha-olefins and
bii) a higher molecular weight polymer which is either a binary copolymer of ethylene and 1-butene, if the lower molecular weight polymer of aii) is a binary copolymer of ethylene and a C 6 to C 12 alpha-olefin, or a terpolymer of ethylene, 1-butene and a comonomer selected from C 6 to C 12 alpha-olefin;
wherein all components are made by the same catalyst.
16. A composition as claimed in claim 15 wherein the C 6 to C 12 alpha-olefin of part bi) is selected from the group consisting of: hex-1-ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and dec-1-ene.
17. A composition as claimed in claim 16 comprising a blend of said polyethylene and a further polymer.
18. A composition as claimed in claim 17 wherein said further polymer is a low density polyethylene (LDPE).
19. A product packaged within a heat-sealed film of a bimodal polyethylene produced by polymerization catalysed by a single site catalyst having more than one eta 5 -cyclic ligand comprising
ai) a lower molecular weight homopolymer of ethylene and
bi) a higher molecular weight terpolymer of ethylene, 1-butene and a C 6 to C 12 alpha-olefin,
or
aii) a lower molecular weight polymer which is a binary copolymer of ethylene and a comonomer selected from C 4 to C 12 alpha-olefin and
bii) a higher molecular weight polymer which is either a binary copolymer of ethylene and 1-butene, if the lower molecular weight polymer of aii) is a binary copolymer of ethylene and a C 6 to C 12 alpha-olefin, or a terpolymer of ethylene, 1-butene and a comonomer selected from C 6 to C 12 alpha-olefin;
wherein all components are made by the same catalyst.
20. A product as claimed in claim 19 wherein the C 6 to C 12 alpha-olefin of part bi) is selected from the group consisting of: hex-1-ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and dec-1-ene.
21. A product as claimed in claim 19 being a packaged foodstuff or liquid.
22. A composition as claimed in claim 15 wherein the comonomer of part aii) is selected from but-1-ene and hex-1-ene.
23. A product as claimed in claim 19 wherein the comonomer of part aii) is selected from but-1-ene and hex-1-ene.