Oriented polyethylene films and a method for making the same
A first oriented film comprising a first polyethylene composition which comprises: from 20 to 50 wt % of a first linear low density polyethylene polymer having a density greater than 0.925 g/cc and an I 2 lower than 2 g/10 min; and from 80 to 50 wt % of a second linear low density polyethylene polymer having a density lower than or equal to 0.925 g/cc and an I 2 greater than or equal to 2 g/10 min; wherein the first polyethylene composition has an I 2 from 0.5 to 10 g/10 min and a density from 0.910 to 0.940 g/cc is provided.
1. A oriented film comprising a polyethylene composition which comprises:
from 20 to 50 wt % of a first linear low density polyethylene polymer having a density greater than 0.925 g/cc and melt index (I 2 ) lower than 2 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg; and
from 80 to 50 wt % of a second linear low density polyethylene polymer having a density lower than 0.925 g/cc and an I 2 greater than 2 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg;
wherein the polyethylene composition has an I 2 from 0.5 to 10 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg, and a density from 0.910 to 0.940 g/cc.
2. The oriented film according to claim 1 , wherein the first and/or second linear low density polyethylene polymer is produced using a Ziegler-Natta catalyst.
3. The oriented film according to claim 1 , wherein the first linear low density polyethylene polymer has a density greater than 0.930 g/cc and an I 2 lower than 1 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg.
4. The oriented film according to claim 1 , wherein the second linear low density polyethylene polymer has a density lower than 0.920 g/cc and an I 2 greater than 4 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg.
5. The oriented film according to claim 1 , wherein the polyethylene composition has a Molecular Weight of High Density Fraction (MW HDF>95 ) greater than 135 kg/mol and a High Density Fraction Index (I HDF>95 ) greater than 42 kg/mol.
6. The oriented film according to claim 1 , wherein the oriented film is oriented below the melting point of the polyethylene composition.
7. The oriented film according to claim 1 , wherein the oriented film is a biaxially oriented film.
8. The oriented film according to claim 1 , wherein the oriented film is a biaxially oriented film which has been oriented via a sequential orientation process with an MID draw ratio greater than 3 and a TD draw ratio greater than 5.
9. The oriented film according to claim 1 , wherein the oriented film is a biaxially oriented film which has been oriented via a simultaneous orientation process with an MD draw ratio greater than 4 and a TD draw ratio greater than 4.
10. A co-extruded film comprising at least one film layer comprising the oriented film according to claim 1 .
11. A laminated film comprising at least one film layer comprising the oriented film according to claim 1 .
12. The oriented film according to claim 1 , wherein the oriented film exhibits one or more of the following properties:
ultimate tensile strength averaged in MD and TD, measured according to ASTM D882, greater than or equal to 40 MPa; and
2% secant modulus averaged in MD and TD, measured according to ASTM D882, greater than or equal to 350 MPa.
13. A biaxially oriented film comprising a polyethylene composition which comprises:
from 20 to 50 wt % of a first linear low density polyethylene polymer having a density greater than 0.925 g/cc and melt index (I 2 ) lower than 2g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg; and
from 80 to 50 wt % of a second linear low density polyethylene polymer having a density lower than 0.925 g/cc and an I 2 greater than 2 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg;
wherein the polyethylene composition has an I 2 from 0.5 to 10 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg, and a density from 0.910 to 0.940 g/cc;
wherein the biaxially oriented film has been oriented via a sequential orientation process with an MD draw ratio greater than 3 and a TD draw ratio greater than 5.
14. A biaxially oriented film comprising a polyethylene composition which comprises:
from 20 to 50 wt % of a first linear low density polyethylene polymer having a density greater than 0.925 g/cc and melt index (I 2 ) lower than 2 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg; and
from 80 to 50 wt % of a second linear low density polyethylene polymer having a density lower than 0.925 g/cc and an I 2 greater than 2 g/10 min, measured according to ASTM D1238, condition 190° C./2.16 kg;
wherein the polyethylene composition has an I 2 from 0.5 to 10 g/10min, measured according to ASTM D1238, condition 190° C./2.16 kg, and a density from 0.910 to 0.940 g/cc;
wherein the biaxially oriented film has been oriented via a simultaneous orientation process with an MD draw ratio greater than 4and a TD draw ratio greater than 4.