Dual Component LLDPE Copolymers with Improved Impact and Tear Resistance, and Methods of Their Preparation

Patent metadata

Field	Value
Publication number	US-2022315744-A1
Application number	US-202217841803-A
Country	US
Kind code	A1
Filing date	Jun 16, 2022
Priority date	Mar 25, 2019
Publication date	Oct 6, 2022
Grant date	—

Abstract

Disclosed are ethylene polymer compositions containing a homogeneously-branched first ethylene polymer component and 15-35 wt. % of 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 ratio of Mw/Mn from 2 to 5, a melt index less than 2 g/10 min, and a CY-a parameter at 190° C. from 0.35 to 0.7. 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. Further, methods for improving film Elmendorf tear strength also are described.

First claim

1 - 20 . (canceled)

21 . An ethylene polymer composition comprising:
(i) a homogeneously-branched first ethylene polymer component; and (ii) a homogeneously-branched second ethylene polymer component having a second component density in a range from about 0.935 to about 0.972 g/cm 3 and a second component melt index in a range from about 0.5 to about 40 g/10 min; wherein the amount of the second ethylene polymer component is in a range from about 15 to about 35 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 2 to about 5;
a melt index in a range from about 0.3 to about 2 g/10 min;
a CY-a parameter in a range from about 0.35 to about 0.7; and
an ATREF curve containing at least two peaks, with a first peak at a temperature in a range from about 60 to about 72° C., and a second peak at a temperature in a range from about 92 to about 104° C.

22 . The composition of claim 21 , wherein:
the second component density is from about 0.94 to about 0.96 g/cm 3 ; and the second component melt index is from about 0.5 to about 8 g/10 min.

23 . The composition of claim 22 , wherein the composition comprises an ethylene homopolymer, an ethylene/α-olefin copolymer, or a combination thereof.

24 . The composition of claim 23 , wherein the amount of the second ethylene polymer component is from about 15 to about 30 wt. %, based on the total weight of the first ethylene polymer component and the second ethylene polymer component.

25 . The composition of claim 23 , wherein the composition is a single reactor product.

26 . The composition of claim 23 , wherein the composition is a post-reactor blend.

27 . The composition of claim 23 , wherein the composition contains no measurable amount of hafnium or titanium.

28 . The composition of claim 23 , wherein the composition is further characterized by:
a Mw in a range from about 100 to about 200 kg/mol; and a ratio of Mz/Mw in a range from about 1.7 to about 2.2.

29 . An article of manufacture comprising the composition of claim 28 .

30 . A film comprising the composition of claim 28 , wherein the film has:
a MD Elmendorf tear strength in a range from about 100 to about 500 g/mil; a haze of less than or equal to about 10%; and a dart impact strength of greater than or equal to about 250 g/mil.

31 . The film of claim 30 , wherein the dart impact strength is greater than or equal to about 500 g/mil.

32 . The composition of claim 21 , 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;

33 . The composition of claim 32 , wherein:
the CY-a parameter is from about 0.4 to about 0.6; and the amount of the second ethylene polymer component is from about 15 to about 28 wt. %, based on the total weight of the first ethylene polymer component and the second ethylene polymer component.

34 . The composition of claim 32 , wherein the composition is further characterized by:
a ratio of HLMI/MI in a range from about 12 to about 25; and a ratio of Mz/Mw in a range from about 1.7 to about 2.5.

35 . The composition of claim 32 , wherein:
the second peak is at a temperature from about 94 to about 102° C.; and a difference between the temperatures (ΔT) of the first peak and the second peak is in a range from about 26 to about 39° C.

36 . The composition of claim 32 , wherein the composition, the first ethylene polymer component, and the second ethylene polymer component, independently, contain less than 10 long chain branches (LCB) per million total carbon atoms.

37 . A film comprising the composition of claim 32 , wherein the film has:
a MD Elmendorf tear strength in a range from about 100 to about 500 g/mil; a haze of less than or equal to about 10%; and a dart impact strength of greater than or equal to about 250 g/mil.

38 . An ethylene polymer composition comprising:
(i) a homogeneously-branched first ethylene polymer component having a first component density in a range from about 0.905 to about 0.918 g/cm 3 ; and (ii) a homogeneously-branched second ethylene polymer component having a second component density in a range from about 0.935 to about 0.972 g/cm 3 and a second component melt index in a range from about 0.5 to about 40 g/10 min; wherein the amount of the second ethylene polymer component is in a range from about 15 to about 35 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 2 to about 5;
a melt index in a range from about 0.3 to about 2 g/10 min;
a CY-a parameter in a range from about 0.35 to about 0.7; and
an ATREF curve containing at least two peaks, with a first peak at a temperature in a range from about 60 to about 72° C., and a second peak at a temperature in a range from about 92 to about 104° C.

39 . The composition of claim 38 , wherein first component density is from about 0.91 to about 0.918 g/cm 3 .

40 . The composition of claim 38 , wherein the composition contain less than 5 long chain branches (LCB) per million total carbon atoms.

41 . The composition of claim 38 , wherein first component is further characterized by a first component melt index in a range from about 0.5 to about 1.8 g/10 min.

42 . A film comprising the composition of claim 38 , wherein the film has:
a MD Elmendorf tear strength in a range from about 100 to about 500 g/mil; a haze of less than or equal to about 10%; and a dart impact strength of greater than or equal to about 250 g/mil.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

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

Classifications

• B29C48/08

  flexible, e.g. films · CPC title

• C08L23/06 Primary

  Polyethylene · CPC title

• C08L2314/06

  Metallocene or single site catalysts · CPC title

• C08J2423/08

  Copolymers of ethene (C08J2423/16 takes precedence) · CPC title

• C08L2203/16

  used for films · CPC title