# US 11,028,258 B2 · Metallocene catalyst system for producing LLDPE copolymers with tear resistance and low haze

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- Number: US 11,028,258 B2
- Document ID: US11028258B2
- Status: Granted
- Kind: B2
- Application number: 16/543,686
- Filed: 2019-08-19
- Published: 2021-02-25
- Granted: 2021-06-08
- Earliest claimed: 2019-08-19
- Assignees: Chevron Phillips Chemical Company LP
- Applicants: Chevron Phillips Chemical Company LP
- Inventors: Chung Ching Tso; Errun Ding; Randall S. Muninger; John T. Blagg; Yongwoo Inn; Max P. McDaniel; Ashish M. Sukhadia; Sarah Eppinger
- Web page: https://patentgrep.com/patent/US11028258B2

## CPC

- C08L 23/06: Polyethylene
- C08F 4/6592: containing at least one cyclopentadienyl ring, condensed or not, e.g. an indenyl or a fluorenyl ring
- C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
- C08L 23/16: Ethylene-propylene or ethylene-propylene-diene copolymers
- C08F 4/65912: {in combination with an organoaluminium compound}
- C08L 2201/10: Transparent films; Clear coatings; Transparent materials
- C08L 2203/16: used for films
- C08L 2207/066: LDPE (radical process)
- C08L 2314/02: Ziegler natta catalyst
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

Ethylene polymers having a density from 0.908 to 0.925 g/cm3, a melt index from 0.5 to 3 g/10 min, a ratio of Mw/Mn from 2 to 4, a ratio of Mz/Mw from 1.6 to 2.3, a CY-a parameter from 0.45 to 0.6, and an ATREF profile characterized by a single peak at a peak ATREF temperature from 76 to 88° C., and by less than 4.5 wt. % of the polymer eluting above a temperature of 91° C. These ethylene polymers can be used to produce various articles of manufacture, such as blown and cast films with a beneficial combination of high tear resistance and low haze.

## Claims

### Claim 1

A film comprising an ethylene polymer, wherein the film has:
a haze in a range from about 2 to about 10%; and
a MD Elmendorf tear strength in a range from about 200 to about 500 g/mil; and wherein the ethylene polymer has:
a density in a range from about 0.908 to about 0.925 g/cm3;
a melt index in a range from about 0.5 to about 3 g/10 min;
a ratio of Mw/Mn in a range from about 2 to about 4;
a ratio of Mz/Mw in a range from about 1.6 to about 2.3;
a CY-a parameter in a range from about 0.45 to about 0.6; and
an ATREF profile characterized by a single peak at a peak ATREF temperature in a range from about 76 to about 88° C., and by less than or equal to about 4.5 wt % of the polymer eluting above a temperature of 91° C.

### Claim 2 (depends on 1)

The film of claim 1, wherein:
the peak ATREF temperature is in a range from about 79 to about 86° C.; and
less than or equal to about 3.5 wt % of the polymer elutes above a temperature of 91° C.

### Claim 3 (depends on 1)

The film of claim 1, wherein:
the haze is in a range from about 2 to about 8%; and
the MD Elmendorf tear strength is in a range from about 250 to about 400 g/mil.

### Claim 4 (depends on 1)

The film of claim 1, wherein:
the ethylene polymer has a unimodal molecular weight distribution; and
the ethylene polymer comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, or a combination thereof.

### Claim 5 (depends on 4)

The film of claim 4, wherein the film is a blown film having an average thickness in a range from about 0.8 to about 5 mils.

### Claim 6 (depends on 4)

The film of claim 4, wherein:
the density is in a range from about 0.91 to about 0.922 g/cm3;
the melt index is in a range from about 1 to about 2.5 g/10 min;
the ratio of Mw/Mn is in a range from about 2.2 to about 3.8;
the ratio of Mz/Mw is in a range from about 1.7 to about 2.2; and
the CY-a parameter is in a range from about 0.5 to about 0.6.

### Claim 7 (depends on 6)

The film of claim 6, wherein the film is a cast film having an average thickness in a range from about 0.5 to about 8 mils.

### Claim 8 (depends on 4)

The film of claim 4, wherein the film has:
a ratio of MD Elmendorf tear strength to TD Elmendorf tear strength (MD:TD) in a range from about 0.5:1 to about 0.9:1; and
a dart impact strength of greater than or equal to about 500 g/mil.

### Claim 9 (depends on 1)

The film of claim 1, wherein the ethylene polymer has:
a Mn in a range from about 25,000 to about 55,000 g/mol; and
a high load melt index (HLMI) in a range from about 18 to about 45 g/10 min.

### Claim 10 (depends on 1)

The film of claim 1, wherein the ethylene polymer has:
a Mz in a range from about 175,000 to about 275,000 g/mol; and
an IB parameter in a range from about 0.9 to about 1.05.

### Claim 11 (depends on 1)

The film of claim 1, wherein:
the haze is in a range from about 2 to about 7%; and
the MD Elmendorf tear strength is in a range from about 300 to about 400 g/mil.

### Claim 12

An ethylene polymer having:
a density in a range from about 0.908 to about 0.925 g/cm3;
a melt index in a range from about 0.5 to about 3 g/10 min;
a ratio of Mw/Mn in a range from about 2 to about 4;
a ratio of Mz/Mw in a range from about 1.6 to about 2.3;
a CY-a parameter in a range from about 0.45 to about 0.6; and
an ATREF profile characterized by a single peak at a peak ATREF temperature in a range from about 76 to about 88° C., and by less than or equal to about 4.5 wt % of the polymer eluting above a temperature of 91° C.

### Claim 13 (depends on 12)

The polymer of claim 12, wherein the ethylene polymer has:
a Mw in a range from about 80,000 to about 180,000 g/mol; and
a relaxation time (τη) in a range from about 4×10−3 sec to about 2×10−2 sec.

### Claim 14 (depends on 13)

An article of manufacture comprising the ethylene polymer of claim 13.

### Claim 15 (depends on 12)

The polymer of claim 12, wherein:
the density is in a range from about 0.91 to about 0.922 g/cm3;
the melt index is in a range from about 1 to about 2.5 g/10 min;
the ratio of Mw/Mn is in a range from about 2.2 to about 3.8;
the ratio of Mz/Mw is in a range from about 1.7 to about 2.2;
the CY-a parameter is in a range from about 0.52 to about 0.59;
the peak ATREF temperature is in a range from about 79 to about 86° C.; and
less than or equal to about 3.5 wt % of the polymer elutes above a temperature of 91° C.

### Claim 16 (depends on 12)

The polymer of claim 12, wherein the ATREF profile is further characterized by from about 0.05 to about 5 wt % of the polymer eluting below a temperature of 40° C., from about 14 to about 45 wt % of the polymer eluting between 40 and 76° C., from about 35 to about 53 wt % of the polymer eluting between 76 and 86° C., and the remainder of the polymer eluting above a temperature of 86° C.

### Claim 17

An ethylene polymer having:
a density in a range from about 0.908 to about 0.925 g/cm3;
a melt index in a range from about 0.5 to about 3 g/10 min;
a ratio of Mw/Mn in a range from about 2 to about 4;
a ratio of Mz/Mw in a range from about 1.6 to about 2.3;
a CY-a parameter in a range from about 0.45 to about 0.6; and
an ATREF profile characterized by a single peak at a peak ATREF temperature in a range from about 76 to about 90° C., by less than or equal to about 12 wt % of the polymer eluting above a temperature of 91° C., and by less than or equal to about 0.1 wt % of the polymer eluting above a temperature of 100° C.

### Claim 18 (depends on 17)

An article of manufacture comprising the ethylene polymer of claim 17.

### Claim 19 (depends on 17)

The polymer of claim 17, wherein:
the peak ATREF temperature is in a range from about 77 to about 89° C.;
less than or equal to about 11 wt % of the polymer elutes above a temperature of 91° C.; and
less than or equal to about 0.07 wt % of the polymer elutes above a temperature of 100° C.

### Claim 20 (depends on 17)

The polymer of claim 17, wherein the ethylene polymer:
has a unimodal molecular weight distribution; and
contains less than 0.1 ppm, independently, of hafnium and titanium.

### Claim 21 (depends on 17)

The polymer of claim 17, wherein:
the ethylene polymer further comprises an additive selected from an antioxidant, an acid scavenger, an antiblock additive, a slip additive, a colorant, a filler, a polymer processing aid, a UV additive, or a combination thereof; and
the ethylene polymer comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, or a combination thereof.