Dual component LLDPE copolymers with improved impact and tear resistance

Patent metadata

Field	Value
Publication number	US-10544273-B2
Application number	US-201916459656-A
Country	US
Kind code	B2
Filing date	Jul 2, 2019
Priority date	Sep 26, 2017
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

Disclosed are ethylene polymer compositions containing a homogeneously-branched first ethylene polymer component and a homogeneously-branched second ethylene polymer component of higher density than the first ethylene polymer component. The ethylene polymer composition can be characterized by a density from 0.912 to 0.925 g/cm 3 , a melt index less than 3.5 g/10 min, and a CY-a parameter at 190° C. from 0.25 to 0.65. These polymer compositions have the excellent dart impact strength and optical properties of a metallocene-catalyzed LLDPE, but with improved machine direction tear resistance, and can be used in blown film and other end-use applications.

First claim

We claim:

1. 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 40 wt. %, based on the total weight of the first ethylene polymer component and the second ethylene polymer component;
wherein the composition contains less than 0.05 ppm, independently, of hafnium and titanium; and
wherein the composition is characterized by:
a density in a range from about 0.912 to about 0.925 g/cm 3 ;
a Mw in a range from about 100 to about 200 kg/mol;
a ratio of Mw/Mn in a range from about 1.8 to about 4.5;
a unimodal molecular weight distribution;
a melt index less than or equal to about 3.5 g/10 min;
less than 10 long chain branches (LCB) per million total carbon atoms;
a CY-a parameter in a range from about 0.35 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 70 to about 82° C., and a second peak at a temperature in a range from about 95 to about 105° C.

2. The composition of claim 1 , wherein the composition:
has a Mw in a range from about 100 to about 180 kg/mol;
and
contains less than 5 long chain branches (LCB) per million total carbon atoms.

3. The composition of claim 1 , 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.

4. The composition of claim 1 , 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 difference between the temperatures (ΔT) of the first peak and the second peak is in a range from about 18 to about 30° C.

5. An article of manufacture comprising the composition of claim 1 .

6. A film comprising the composition of claim 1 , wherein the film has:
a MD Elmendorf tear strength in a range from about 100 to about 450 g/mil;
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; and
an average thickness in a range from about 0.5 to about 8 mils.

7. The film of claim 6 , wherein:
the film contains less than 0.05 ppm, independently, of hafnium and titanium;
the film has a haze of less than or equal to about 10%;
the film has a dart impact strength of greater than or equal to about 500 g/mil;
the MD Elmendorf tear strength is in a range from about 125 to about 425 g/mil; and
the film has a TD Elmendorf tear strength in a range from about 200 to about 800 g/mil.

8. An article of manufacture comprising the composition of claim 2 .

9. 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 10 to about 25 wt. %, based on the total weight of the first ethylene polymer component and the second ethylene polymer component;
wherein the composition contains less than 0.1 ppm, independently, of hafnium and titanium; and
wherein the composition is characterized by:
a density in a range from about 0.912 to about 0.922 g/cm 3 ;
a ratio of Mw/Mn in a range from about 2.2 to about 3.8;
a melt index in a range from about 0.5 to about 1.8 g/10 min;
a CY-a parameter in a range from about 0.45 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 95 to about 105° C.

10. The composition of claim 9 , wherein:
the composition comprises an ethylene homopolymer, an ethylene/α-olefin copolymer, or a combination thereof;
the composition has a Mw in a range from about 100 to about 200 kg/mol; and
the difference between the temperatures (ΔT) of the first peak and the second peak is in a range from about 18 to about 32° C.

11. The composition of claim 10 , wherein the composition contains less than 10 long chain branches (LCB) per million total carbon atoms.

12. An article of manufacture comprising the composition of claim 11 .

13. A film comprising the composition of claim 11 , wherein the film has:
a haze in a range from about 2 to about 9%;
a MD Elmendorf tear strength in a range from about 125 to about 425 g/mil; and
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.

14. The composition of claim 9 , wherein:
the first peak is at a temperature in a range from about 70 to about 82° C.;
the second peak is at a temperature in a range from about 96 to about 105° C.; and
the difference between the temperatures (ΔT) of the first peak and the second peak is in a range from about 18 to about 32° C.

15. An article of manufacture comprising the composition of claim 14 .

16. The composition of claim 14 , wherein:
the composition comprises an ethylene homopolymer, an ethylene/α-olefin copolymer, or a combination thereof;
the composition has a Mw in a range from about 100 to about 200 kg/mol; and
the composition contains less than 10 long chain branches (LCB) per million total carbon atoms.

17. The composition of claim 16 , wherein:
the composition has a Mw in a range from about 100 to about 180 kg/mol; and
the composition contains less than 5 long chain branches (LCB) per million total carbon atoms.

18. A film comprising the composition of claim 16 , wherein the film has:
a MD Elmendorf tear strength in a range from about 125 to about 425 g/mil; and
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.

19. The film of claim 18 , wherein:
the film is a blown film with a haze in a range from about 3 to about 8%; or
the film is a cast film with a haze in a range from about 2 to about 9%.

20. An article of manufacture comprising the composition of claim 9 .

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Praetorius Jeremy M
• Tso Chung C
• Yang Qing
• Inn Yongwoo
• Blagg John T
• Sukhadia Ashish M

Classifications

• C08L2207/066

  LDPE (radical process) · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• C08L2203/16

  used for films · CPC title

• C08J2323/06

  Polyethene · CPC title