Oriented polyethylene films and a method for making the same

Patent metadata

Field	Value
Publication number	US-12110371-B2
Application number	US-202117206918-A
Country	US
Kind code	B2
Filing date	Mar 19, 2021
Priority date	Apr 9, 2014
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

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 I2 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 I2 greater than or equal to 2 g/10 min; wherein the first polyethylene composition has an I2 from 0.5 to 10 g/10 min and a density from 0.910 to 0.940 g/cc is provided.

First claim

We claim:

1. An oriented film comprising a polyethylene composition comprising:
75 to less than 100 wt % of a first polyethylene composition; and
greater than 0 to 25 wt % of at least one resin selected from the group consisting of linear low density polyethylene, low density polyethylene, ethylene copolymers, propylene copolymers and high density polyethylene;
wherein the first polyethylene composition 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 0.925 g/cc and an I 2 greater than 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.

2. The oriented film according to claim 1 , wherein the first polyethylene composition has an MWHDF>95 greater than 135 kg/mol and IHDF>95 greater than 42 kg/mol.

3. The oriented film according to claim 1 , wherein the oriented film is oriented below the melting point of the first polyethylene composition.

4. The oriented film according to claim 1 , wherein the first polyethylene composition comprises from 20 to 45 wt. % of the first linear low density polyethylene polymer.

5. The oriented film according to claim 1 , wherein the at least one resin is selected from the group consisting of low density polyethylene, ethylene copolymers, propylene copolymers and high density polyethylene.

6. The oriented film according to claim 1 , wherein the at least one resin is a propylene copolymer.

7. The oriented film according to claim 1 , wherein the polyethylene composition further comprises a second polyethylene composition, wherein the second polyethylene composition comprises from 50 to 80 wt % of a third linear low density polyethylene polymer having a density greater than 0.925 g/cc and an I 2 less than 2 g/10 min; and
from 50 to 20 wt % of a fourth linear low density polyethylene polymer having a density lower than 0.920 g/cc and an I 2 greater than 2 g/10 min;
wherein the second 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.

8. The oriented film according to claim 1 , wherein the oriented film is a biaxially oriented film.

9. The biaxially oriented film according to claim 8 which has been oriented via a sequential orientation process with an MD draw ratio greater than 3 and a TD draw ratio greater than 5.

10. The biaxially oriented film according to claim 8 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.

11. A co-extruded 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.

Assignees

• Dow Global Technologies Llc

Inventors

• Lin Yijian
• Demirors Mehmet
• Pan Jianping
• Yun Xiao B

Classifications

• C08L2314/02

  Ziegler natta catalyst · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L2203/16

  used for films · CPC title

• C08L23/06

  Polyethylene · CPC title

• C08J2423/06

  Polyethene · CPC title