Gas phase polyethylene copolymers

Patent metadata

Field	Value
Publication number	US-11767384-B2
Application number	US-202017091217-A
Country	US
Kind code	B2
Filing date	Nov 6, 2020
Priority date	Nov 14, 2019
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

Polyethylene copolymers with a structure that provides improved film properties are provided. The copolymers can have a density of about 0.905 to about 0.911 g/cm 3 . The copolymers can also have a DRI/I2 ratio of about 0.0008 to about 0.060, an I2 value of about 0.6 to about 3.8 dg/min, and an I21 value of about 8 to about 57 dg/min. The copolymers having those properties can be produced by introducing ethylene and at least one other olefin comonomer to a single reactor at a comonomer/ethylene mole ratio of about 0.02 to about 0.03 and polymerizing at a temperature of about 76.7° C. to about 80.6° C. and a pressure of about 1,724 kPa to about 2,413 kPa. The copolymers can be used to make films having a 21 mol % O 2 transmission rate of about 150 to about 200 cc/100 in 2 /24 hr. and hot tack seal initiation temperatures of about 65° C. to 80° C.

First claim

What is claimed is:

1. An ethylene copolymer, comprising:
about 92.5 mol % to about 97.5 mol % ethylene derived units; and
about 2.5 mol % to about 7.5 mol % hexene-derived units,
wherein the copolymer has
a density of about 0.905 g/cm 3 to about 0.911 g/cm 3 ;
a first Melt Index (I2) of about 0.4 to about 3.4 dg/min, as measured according to ASTM D138(190° C./2.16 kg);
a second Melt Index (I21) of about 5 to about 60 dg/min, as measured according to ASTM D138 (190° C./21.6 kg);
a Melt flow ratio (I21/I2) of about 16 to about 17; and
a Dow Rheology Index (DRI)/Melt Index (I2) ratio (DRI/I2) of about 0.007 to about 0.060;

wherein the copolymer is produced by
introducing the ethylene and the 1-hexene to a single gas phase reactor at a 1-hexene/ethylene mole ratio of about 0.02 to about 0.03, as determined by measuring moles of the 1-hexene and the ethylene in a vapor overhead of the single reactor; and
polymerizing the ethylene and the 1-hexene at a temperature of about 75.56° C. to about 80° C. and a pressure of from 290.0 psig to 299.7 psig.

2. The copolymer of claim 1 , further having a density of about 0.907 g/cm 3 to about 0.911 g/cm 3 .

3. The copolymer of claim 2 , having one or both of the following properties:
(a-1) a density of about 0.908 g/cm 3 to about 0.910 g/cm 3 ; and
(b-1) a DRI/I2 ratio of about 0.007 to about 0.028.

4. A film made from the copolymer of claim 1 , the film having:
(a) a thickness of about 1 mil;
(b) a 21 mol % oxygen transmission rate of about 150 to about 200 cc/100 in 2 /24 hr; and
(c) a hot tack seal initiation temperature of about 65° C. to about 80° C.

5. The film of claim 4 , having one or both of the following properties:
(b-1) the 21 mol % oxygen transmission rate of 160 to 200 cc/100 in 2 2/24 hr; and
(c-1) the hot tack seal initiation temperature of 67° C. to 78° C.

6. The film of claim 5 , having one or both of the following properties:
(b-2) the 21 mol % oxygen transmission rate of 170 to 190 cc/100 in 2 /24 hr; and
(c-2) the hot tack seal initiation temperature of 70° C. to 75° C.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Shannon Porter C
• Bennett Handel D
• Guy Nathaniel B
• O'Neil Daniel G
• Schulze James L
• Tribo Michael G

Classifications

• C08F210/02 Primary

  Ethene · CPC title

• C08F210/14

  Monomers containing five or more carbon atoms · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C09K3/10

  {Materials in mouldable or extrudable form} for sealing or packing joints or covers (filling pastes C09D5/34) · CPC title

• C08F2800/10

  as molar percentages · CPC title