# US 10,308,776 B2 · Polyethylene films and method of making same

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- Number: US 10,308,776 B2
- Document ID: US10308776B2
- Status: Granted
- Kind: B2
- Application number: 14/649,834
- Filed: 2013-12-04
- Published: 2015-12-24
- Granted: 2019-06-04
- Earliest claimed: 2012-12-18
- Assignees: ExxonMobil Chemical Patents Inc.
- Applicants: ExxonMobil Chemical Patents Inc.
- Inventors: David Michael Fiscus; Danny Van Hoyweghen
- Web page: https://patentgrep.com/patent/US10308776B2

## CPC

- C08J 5/18: Manufacture of films or sheets
- B29C 48/08: flexible, e.g. films
- B29C 48/21: the layers being joined at their surfaces
- B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)}
- B32B 27/327: {comprising polyolefins obtained by a metallocene or single-site catalyst}
- B29K 2023/06: {PE, i.e. polyethylene}
- B29K 2995/0064: Non-uniform density
- B29K 2995/0081: Tear strength
- B29L 2007/00: Flat articles, e.g. films or sheets (B29L2024/00 takes precedence)
- B29L 2009/00: Layered products
- B32B 2270/00: Resin or rubber layer containing a blend of at least two different polymers
- B32B 2307/558: Impact strength, toughness
- B32B 2307/5825: Tear resistant
- B32B 2307/72: Density
- C08J 2323/06: Polyethene
- C08J 2323/08: Copolymers of ethene (C08J2323/16 takes precedence)
- Y10T 428/269: including synthetic resin or polymer layer or component
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention is directed to polyethylene films having improved properties. Particularly, relatively thick films having improved tear properties and methods of improving tear, and multilayer films having improved dart impact strength and methods of improving the Dart impact strength.

## Claims

### Claim 1

A method of improving the MD Elmendorf Tear strength of a co-extruded, blown multilayer film, the method comprising:
a) providing a first layer comprising:
i) 5.0 wt % to 35.0 wt % of a first polyethylene having a g′vis of ≤0.97, 0.05 long-chain branches per 1,000 carbon atoms to 0.5 long-chain branches per 1,000 carbon atoms, a density of 0.920 to 0.935 g/cm3, and a melt index of 0.1 g/10 min to 0.5 g/10 min; and
ii) 95.0 wt % to 65.0 wt % of a second polyethylene having a hafnium : zirconium (ppm/ppm) ratio of ≥1.0, a CDBI of <50%, and a g′vis of ≥0.98, wherein the wt % values are based on the total weight of the first layer, wherein:
the density of the first polyethylene is greater than a density of the second polyethylene,
the melt index of the first polyethylene is less than a melt index of the second polyethylene, or
the density of the first polyethylene is greater than a density of the second polyethylene and the melt index of the first polyethylene is less than a melt index of the second polyethylene;
b) providing a second layer in surface contact with a first surface of the first layer, the second layer comprising:
i) 80.0 wt % to 100.0 wt % of a third polyethylene, wherein the third polyethylene has a hafnium:zirconium (ppm/ppm) ratio of greater than 1.0, a CDBI of <50%, and a g′vis of ≥0.98; and
ii) 0.0 wt % to 20.0 wt % of a fourth polyethylene, wherein the wt % values are based on the total weight of the second layer;
c) providing a third layer in surface contact with a second surface of the first layer, the third layer comprising:
i) 80.0 wt % to 100.0 wt % of a fifth polyethylene, wherein the fifth polyethylene has a hafnium : zirconium (ppm/ppm) ratio of greater than 1.0, a CDBI of <50%, and a g′vis of ≥0.98; and
ii) 0.0 wt % to 20.0 wt % of a sixth polyethylene, wherein the wt % values are based on the total weight of the third layer;
wherein each of the third polyethylene, the fourth polyethylene, the fifth polyethylene, and the sixth polyethylene may be the same or different.

### Claim 2 (depends on 1)

The method of claim 1, wherein the second polyethylene has at least a first peak and a second peak in a comonomer distribution analysis, wherein the first peak has a maximum at a log(Mw) value of 4.0 to 5.4 and a TREF elution temperature of 70.0° C. to 100.0° C. and the second peak has a maximum at a log(Mw) value of 5.0 to 6.0 and a TREF elution temperature of 40.0° C. to 70.0° C.

### Claim 3 (depends on 1)

The method of claim 1, wherein the second polyethylene has at least one property selected from the group consisting of:
a melt index of 0.1 g/10 min to 5.0 g/10 min,
a melt index ratio of 20 to 40,
a Mw of 20,000 g/mol to 200,000 g/mol,
a Mw/Mn of 2.0 to 4.5, and
a density of 0.910 g/cm3 to 0.925 g/cm3.

### Claim 4 (depends on 1)

The method of claim 1, wherein the film has a MD Elmendorf Tear of about 500.0 g/mil to about 1,000.0 g/mil.

### Claim 5 (depends on 1)

The method of claim 1, wherein the density of the first polyethylene is greater than a density of the second polyethylene.

### Claim 6 (depends on 1)

The method of claim 1, wherein the second polyethylene has a melt index of 0.6 g/10 min to 5 g/10 min.

### Claim 7 (depends on 1)

The method of claim 1, wherein the density of the first polyethylene is greater than a density of the second polyethylene, and wherein the second polyethylene has a melt index of 0.6 g/10 min to 5 g/10 min.

### Claim 8 (depends on 1)

The method of claim 1, wherein the second polyethylene has:
a melt index of 0.6 g/10 min to 5.0 g/10 min,
a melt index ratio of 20 to 40,
a Mw of 20,000 g/mol to 200,000 g/mol,
a Mw/Mn of 2.0 to 4.5, and
a density of 0.910 g/cm3 to 0.925 g/cm3.

### Claim 9 (depends on 1)

The method of claim 1, wherein the density of the first polyethylene is greater than a density of the second polyethylene, and wherein the second polyethylene has:
a melt index of 0.6 g/10 min to 5.0 g/10min,
a melt index ratio of 20 to 40,
a Mw of 20,000 g/mol to 200,000 g/mol,
a Mw/Mn of 2.0 to 4.5, and
a density of 0.910 g/cm3 to 0.925 g/cm3.

### Claim 10 (depends on 1)

The method of claim 1, wherein the second polyethylene has at least a first peak and a second peak in a comonomer distribution analysis, wherein the first peak has a maximum at a log(Mw) value of 4.0 to 5.4 and a TREF elution temperature of 70.0° C. to 100.0° C. and the second peak has a maximum at a log(Mw) value of 5.0 to 6.0 and a TREF elution temperature of 40.0° C. to 60.0° C.

### Claim 11 (depends on 1)

The method of claim 1, wherein the second polyethylene has at least a first peak and a second peak in a comonomer distribution analysis, wherein the first peak has a maximum at a log(Mw) value of 4.3 to 5.0 and a TREF elution temperature of 80.0° C. to 95.0° C. and the second peak has a maximum at a log(Mw) value of 5.3 to 5.7 and a TREF elution temperature of 45.0° C. to 60.0° C.

### Claim 12 (depends on 1)

The method of claim 1, wherein the second polyethylene has at least a first peak and a second peak in a comonomer distribution analysis, wherein the first peak has a maximum at a log(Mw) value of 4.5 to 4.7 and a TREF elution temperature of 85.0° C. to 90.0° C. and the second peak has a maximum at a log(Mw) value of 5.4 to 5.6 and a TREF elution temperature of 48.0° C. to 54.0° C.

### Claim 13 (depends on 1)

The method of claim 1, wherein:
the density of the first polyethylene is greater than a density of the second polyethylene, and wherein the second polyethylene has:
a melt index of 0.6 g/10 min to 5.0 g/10 min,
a melt index ratio of 20 to 40,
a Mw of 20,000 g/mol to 200,000 g/mol,
a Mw/Mn of 2.0 to 4.5,
at least a first peak and a second peak in a comonomer distribution analysis, wherein the first peak has a maximum at a log(Mw) value of 4.5 to 4.7 and a TREF elution temperature of 85.0° C. to 90.0° C. and the second peak has a maximum at a log(Mw) value of 5.4 to 5.6 and a TREF elution temperature of 48.0° C. to 54.0° C.

### Claim 14

A method for making a film having a thickness of about 20.0 μm to about 100.0 μm, the method comprising:
a) providing a Layer A comprising:
i) about 5.0 wt % to about 35.0 wt % of a first polyethylene having a g′vis of ≤0.97, 0.05 long-chain branches per 1,000 carbon atoms to 0.5 long-chain branches per 1,000 carbon atoms, a density of 0.920 g/cm3 to 0.935 g/cm3, and a melt index of 0.1 g/10 min to 0.5 g/10 min; and
ii) 95.0 wt % to 65.0 wt % of a second polyethylene comprising ≥50.0 wt % of polymer units derived from ethylene and ≤50.0 wt % of polymer units derived from a C3 to C20 comonomer, based on the weight of the second polyethylene, wherein the second polyethylene has a CDBI of ≥60%, and a g′vis of ≥0.98; wherein the wt % values are based on the total weight of Layer A, and wherein:
the density of the first polyethylene is greater than a density of the second polyethylene,
the melt index of the first polyethylene is less than a melt index of the second polyethylene, or
the density of the first polyethylene is greater than a density of the second polyethylene and the melt index of the first polyethylene is less than a melt index of the second polyethylene,
b) providing a Layer B in surface contact with a first surface of Layer A, the Layer B comprising:
i) 80.0 wt % to 100.0 wt % of a third polyethylene, wherein the third polyethylene comprises ≥50.0 wt % of polymer units derived from ethylene and ≤50.0 wt % of polymer units derived from a C3 to C20 comonomer, based on the weight of the third polyethylene, wherein the third polyethylene has a CDBI of ≥60%, a density of 0.910 g/cm3 to 0.950 g/cm3, and a g′vis of >0.98; and
ii) 0.0 wt % to 20.0 wt % of a fourth polyethylene, wherein the wt % values are based on the total weight of the Layer B; and
c) providing a Layer C in surface contact with a second surface of Layer A, the Layer C comprising:
i) 80.0 wt % to 100.0 wt % of a fifth polyethylene, wherein the fifth polyethylene comprises ≥50.0 wt % of polymer units derived from ethylene and ≤50.0 wt % polymer units derived from a C3 to C20 comonomer, based on the weight of the fifth polyethylene, and wherein the fifth polyethylene has a CDBI of ≥60%, a density of 0.910 g/cm3 to 0.950 g/cm3 and a g′vis of >0.98; and
0.0 wt % to 20.0 wt % of a sixth polyethylene, wherein the wt % values are based on the total weight of the Layer C;
wherein each of the third polyethylene, the fourth polyethylene, the fifth polyethylene, and the sixth polyethylene may be the same or different.

### Claim 15 (depends on 14)

The method of claim 14, wherein the second polyethylene has a melt index of 0.8 g/10 min to 1.5 g/10 min.

### Claim 16 (depends on 4)

The method of claim 4, wherein the second polyethylene has a density of 0.910 g/cm3 to 0.925 g/cm3.

### Claim 17 (depends on 14)

The method of claim 14, wherein the film has an MD Elmendorf Tear of about 500.0 g/mil to about 1,000.0 g/mil.

### Claim 18 (depends on 14)

The method of claim 14, wherein the density of the first polyethylene is greater than a density of the second polyethylene.

### Claim 19 (depends on 14)

The method of claim 14, wherein the melt index of the first polyethylene is less than a melt index of the second polyethylene.

### Claim 20 (depends on 14)

The method of claim 14, wherein the density of the first polyethylene is greater than a density of the second polyethylene and the melt index of the first polyethylene is less than a melt index of the second polyethylene.