Dual component LLDPE copolymers with improved impact and tear resistance

1. A film comprising an ethylene polymer composition, the composition comprising:

(i) a homogeneously-branched first ethylene polymer component; and

(ii) a homogeneously-branched second ethylene polymer component of higher density than the first ethylene polymer component;

wherein the amount of the second ethylene polymer component is in a range from about 4 to about 50 wt. %, based on the total weight of the first ethylene polymer component and the second ethylene polymer component; and

wherein the composition is characterized by:

a density in a range from about 0.912 to about 0.925 g/cm 3 ;

a ratio of Mw/Mn in a range from about 1.8 to about 4.5;

a melt index less than or equal to about 3.5 g/10 min;

a CY-a parameter in a range from about 0.25 to about 0.65; and

an ATREF curve containing at least two peaks, with a first peak at a temperature in a range from about 67 to about 82° C., and a second peak at a temperature in a range from about 92 to about 105° C.

2. The film of claim 1 , wherein the film has a MD Elmendorf tear strength in a range from about 100 to about 450 g/mil.

3. The film of claim 1 , wherein the film has a ratio of MD Elmendorf tear strength to TD Elmendorf tear strength (MD:TD) in a range from about 0.3:1 to about 0.8:1.

4. The film of claim 1 , wherein the film is a blown film having an average thickness in a range from about 0.5 to about 8 mils.

5. The film of claim 1 , wherein the film is a cast film having an average thickness in a range from about 0.7 to about 2 mils.

6. The film of claim 1 , wherein the film has:

a haze of less than or equal to about 10%; and

a dart impact strength of greater than or equal to about 500 g/mil.

7. The film of claim 1 , wherein the film has:

a MD Elmendorf tear strength in a range from about 125 to about 425 g/mil; and

a TD Elmendorf tear strength in a range from about 200 to about 800 g/mil.

8. The film of claim 1 , wherein:

the composition has a Mw in a range from about 100 to about 200 kg/mol; and

the composition comprises an ethylene homopolymer, an ethylene/α-olefin copolymer, or a combination thereof.

9. The film of claim 1 , wherein the composition contains no measurable amount of hafnium or titanium.

10. The film of claim 1 , wherein:

the density is in a range from about 0.912 to about 0.922 g/cm 3 ;

the ratio of Mw/Mn is in a range from about 2.2 to about 3.8;

the melt index is in a range from about 0.5 to about 1.8 g/10 min; and

the CY-a parameter is in a range from about 0.35 to about 0.65.

11. The film of claim 1 , wherein the amount of the second ethylene polymer component is in a range from about 4 to about 25 wt. %, based on the total weight of the first ethylene polymer component and the second ethylene polymer component.

12. The film of claim 1 , wherein a ratio of the Mw of the first ethylene polymer component to the Mw of the second ethylene polymer component is in a range from about 1.1:1 to about 2.5:1.

13. The film of claim 1 , wherein a ratio of the Mw of the first ethylene polymer component to the Mw of the second ethylene polymer component is in a range from about 0.5:1 to about 0.9:1.

14. The film of claim 1 , wherein the difference between the temperatures (ΔT) of the first peak and the second peak is in a range from about 17 to about 32° C.

15. The film of claim 1 , wherein the first peak is at a temperature in a range from about 68 to about 80° C., and the second peak is at a temperature in a range from about 94 to about 105° C.

16. An ethylene polymer composition comprising:

(i) a homogeneously-branched first ethylene polymer component; and

(ii) a homogeneously-branched second ethylene polymer component of higher density than the first ethylene polymer component;

wherein the amount of the second ethylene polymer component is in a range from about 4 to about 50 wt. %, based on the total weight of the first ethylene polymer component and the second ethylene polymer component; and

wherein the composition is characterized by:

a density in a range from about 0.912 to about 0.925 g/cm 3 ;

a ratio of Mw/Mn in a range from about 1.8 to about 4.5;

a melt index less than or equal to about 3.5 g/10 min;

a CY-a parameter in a range from about 0.25 to about 0.65; and

an ATREF curve containing at least two peaks, with a first peak at a temperature in a range from about 67 to about 82° C., and a second peak at a temperature in a range from about 92 to about 105° C.

17. The composition of claim 16 , wherein the composition:

has a Mw in a range from about 100 to about 200 kg/mol;

has a unimodal molecular weight distribution;

contains no measurable amount of hafnium or titanium; and

contains less than 10 long chain branches (LCB) per million total carbon atoms.

18. The composition of claim 16 , wherein:

the composition comprises an ethylene homopolymer, an ethylene/α-olefin copolymer, or a combination thereof;

the composition is a single reactor product; and

the difference between the temperatures (ΔT) of the first peak and the second peak is in a range from about 17 to about 32° C.

19. The composition of claim 16 , wherein:

the composition comprises an ethylene homopolymer, an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, or any combination thereof;

the composition is a post-reactor blend; and

the first peak is at a temperature in a range from about 68 to about 80° C., and the second peak is at a temperature in a range from about 94 to about 105° C.

20. An article of manufacture comprising the composition of claim 16 .