Oriented films comprising ethlyene-based polymers and methods of making same
AssigneeExxonMobil Chemical Patents Inc.
InventorsEtienne R. H. Lernoux, Giriprasath Gururajan, Donald A. Winesett, Stefan B. Ohlsson
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Abstract
Provided are oriented films comprising linear low density polyethylene polymer and having improved balance of properties including improved machine direction tear strength. The oriented polymer film has at least one layer comprising 50 to 100 wt. % of an ethylene-based polymer. The MDO polymer film has a normalized MD Elmendorf Tear (ASTM D-1922) of at least 40 g/μm. In certain embodiments, the MDO polymer film surprisingly does not tear when MD Elmendorf Tear is measured according to ASTM D-1922.
Claims24
A machine direction oriented (MDO) polymer film obtained by:
- stretching a polymer film having a gauge of from 11 to 120 μm and comprising at least one layer comprising 50 to 100 wt. % of an ethylene-based polymer having:
- i. a melt index (I2.16) of from about 0.1 g/10 min to about 10.0 g/10 min;
- ii. a melt index ratio (I21.6/I2.16) of from about 15 to about 45;
- iii. a weight average molecular weight (Mw) of from about 20,000 to about 200,000;
- iv. a molecular weight distribution (Mw/Mn) of from about 2.0 to about 5.0;
- v. a Mz/Mw ratio of from 1.7 to about 3.5;
- and
- vi. a density of from 0.900 to 0.925 g/cm3,
- wherein:
- stretching is performed at a temperature less than the melting point of the polymer to a MDO draw ratio of from 11 to 6.0 sufficient to produce the MDO polymer film;
- and
- the MDO polymer film has a gauge from 10 to 20 μm and a normalized MD Elmendorf Tear of at least 40 g/μm.
A method to produce a machine direction oriented (MDO) polymer film comprising:
- stretching a polymer film having a gauge of from 11 to 120 μm at a temperature less than the melting point of the polymer to a MDO draw ratio of from 1.1 to 6.0 sufficient to produce the MDO polymer film, wherein:
- the polymer film comprises at least one layer comprising 50 to 100 wt. % of an ethylene-based polymer having:
- i. a melt index (I2.16) of from about 0.1 g/10 min to about 10.0 g/10 min;
- ii. a melt index ratio (I21.6/I2.16) of from about 15 to about 45;
- iii. a weight average molecular weight (Mw) of from about 20,000 to about 200,000;
- iv. a molecular weight distribution (Mw/Mn) of from about 2.0 to about 5.0;
- v. a Mz/Mw ratio of from 1.7 to about 3.5;
- and
- vi. a density of from 0.900 to 0.925 g/cm3;
- the MDO polymer film has a gauge of from 10 to 20 μm and a normalized MD Elmendorf Tear of at least 40 g/μm.
Dependencies are inferred from the claim text.