IP Library Granted Patent US 8,835,569
Granted Patent B2
US 8,835,569 · App. 13/808,724 · Granted Sep 16, 2014

Fractional melt index polyethylene composition and films made therefrom

Inventors: Lawrence J. Effler (Rosharon, TX); Cornelis F. J. den Doelder (Terneuzen, NL); Mehmet Demirors (Pearland, TX); Jian Wang (Rosharon, TX)
Assignee: Dow Global Technologies LLC
C08L23/06
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Quick Facts
Patent No.
US 8,835,569
App. No.
13/808,724
Granted
Sep 16, 2014
Kind
B2
Abstract

A reactor blend polyethylene composition comprising: from 35 to 70 percent by weight of a first polyethylene component; and a second polyethylene component; wherein the polyethylene resin has a melt index I 2 of less than 1 dg/min and greater than or equal to 0.25 dg/min and exhibits a V0.1/V100 of greater than or equal to 9; and wherein the first and second polyethylene components are produced in continuous dual solution polymerization reactors, wherein the second polyethylene component is produced in the presence of the first polyethylene component and wherein a Ziegler-Natta catalyst is present in each of the first and second polymerization reactors is provided. Also provided are methods for producing the polyethylene resin and films made therefrom.

Claims (22)

1. A reactor blend polyethylene composition comprising:

from 35 to 70 percent by weight of a first polyethylene component; and

a second polyethylene component;

wherein the polyethylene composition has a melt index I 2 of less than 1 dg/min and greater than or equal to 0.25 dg/min and exhibits a V0.1/V100 of greater than or equal to 9;and

wherein the first and second polyethylene components are produced in continuous dual solution polymerization reactors, wherein the second polyethylene component is produced in the presence of the first polyethylene component and wherein a Ziegler-Natta catalyst is present in each of the first and second polymerization reactors.

2. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a density from 0.90 to 0.94 g/cc.

3. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a density from 0.915 to 0.930 g/cc.

4. The polyethylene composition according claim 1 , wherein the polyethylene composition has a melt strength of at least 4.5 cN.

5. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a melt strength of at least 6.0 cN.

6. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a Mw/Mn of equal to or greater than 5.

7. The polyethylene composition according to claim 1 , wherein the Ziegler-Natta catalyst in the first polymerization reactor is the same or different as the Ziegler-Natta catalyst in the second polymerization reactor.

8. The polyethylene composition according claim 1 , wherein the polyethylene composition has a melt index (I 2 ) from 0.3 to 0.75 dg/min.

9. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a melt index (I 2 ) from 0.4 to 0.6 dg/min.

10. The polyethylene composition according to claim 1 , wherein the polyethylene composition may be used in a blown film process at motor load, screen pressures and melt temperatures within 10% of those of a polyethylene resin having a melt index (I 2 ) of equal to or greater than 1 and achieving at least a 10% increase in output rate in comparison to the polyethylene resin having a melt index (I 2 ) of equal to or greater than 1.

11. A process for producing a reactor blend polyethylene composition comprising:

polymerizing from 35 to 70 percent by weight of a first polyethylene component in the presence of a first Ziegler-Natta catalyst in a first polymerization reactor to make a first reactor product having a melt index (I 2 ) of less than 0.1;

continuously passing the first reactor product to a second polymerization reactor, wherein the second polymerization reactor contains a second Ziegler-Natta catalyst to make the reactor blend polyethylene composition;

wherein the polyethylene composition has a melt index (I 2 ) less than 1 dg/min and greater than or equal to 0.25 dg/min.

12. A film comprising the polyethylene composition of claim 1 .

13. The film according to claim 12 , wherein the film has a dart value within 10% of that of a polyethylene composition having a melt index (I 2 ) of equal to or greater than 1.

14. The film according to claim 13 , wherein the film has a tensile strength within 10% of that of a polyethylene composition having a melt index (I 2 ) of equal to or greater than 1.

15. The film according to claim 14 , wherein the film has a puncture resistance within 10% of that of a polyethylene composition having a melt index (I 2 ) of equal to or greater than 1.

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 5, 2014
From: DEN DOELDER, CORNELIS F.J.
To: DOW BENELUX B.V.
Reel/Frame 033034/0713 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 5, 2014
From: DOW BENELUX B.V.
To: THE DOW CHEMICAL COMPANY
Reel/Frame 033034/0731 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 5, 2014
From: THE DOW CHEMICAL COMPANY
To: DOW GLOBAL TECHNOLOGIES LLC
Reel/Frame 033035/0194 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 5, 2014
From: EFFLER, LAWRENCE J.; DEMIRORS, MEHMET; WANG, JIAN
To: DOW GLOBAL TECHNOLOGIES LLC
Reel/Frame 033035/0251 →
Continuity (2)
Provisional Application 61503051 · Jun 30, 2011
Related Publication 20140100336A1 · Apr 10, 2014