Polyethylene composition and articles made therefrom

Patent metadata

Field	Value
Publication number	US-9988473-B2
Application number	US-201414785727-A
Country	US
Kind code	B2
Filing date	Apr 22, 2014
Priority date	May 2, 2013
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A polyethylene composition comprising at least 95 percent by weight of the units derived from ethylene; less than 5 percent by weight of units derived from one or more α-olefin comonomers; wherein said polyethylene composition has a density in the range of 0.930 to 0.945 g/cm 3 , a molecular weight distribution characterized by the ratio of the z-average molecular weight to the weight average molecular weight (Mz/Mw) less than 5, a melt index, I 2 (measured at 190° C., 2.16 kg), in the range of 0.08 to 0.5 g/10 minutes, and a high flow melt index, I 21 (measured at 190° C., 21.6 kg), in the range from 10 to 20 g/10 minutes; and wherein the polyethylene composition is produced utilizing a chromium oxide catalyst is provided.

First claim

We claim:

1. A polyethylene composition comprising:
at least 95 percent by weight of the units derived from ethylene;
less than 5 percent by weight of units derived from one or more α-olefin comonomers;
wherein said polyethylene composition has a density in the range of 0.930 to 0.945 g/cm 3 , a molecular weight distribution characterized by the ratio of the z-average molecular weight to the weight average molecular weight (Mz/Mw) less than 5, a melt index, I 2 (measured at 190° C., 2.16 kg), in the range of 0.08 to 0.5 g/10 minutes, and a high flow melt index, 1 21 (measured at 190° C., 21.6 kg), in the range from 10 to 20 g/10 minutes; and wherein the polyethylene composition has a vinyl unsaturation of less than 1 vinyls per one thousand carbon atoms present in the backbone of said composition, and wherein the polyethylene composition has a complex viscosity ratio, η* at 0.02 s −1 and 190° C. to η* at 200 s −1 and 190° C., greater than 90.

2. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a density from 0.934 to 0.942 g/cm 3 .

3. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a complex viscosity (η*), determined at 0.02 s −1 and 190° C., of at least 100,000 Pa·s.

4. An article comprising the polyethylene composition according to claim 1 , wherein the article exhibits one or more of the following properties: a 45 degree gloss of at least 10%, a total haze of less than 60%.

5. The article according to claim 4 , wherein the article is an extrusion blow molded article.

6. The article according to claim 4 , wherein the article is a film comprising at least one layer which comprises the polyethylene composition.

7. The film according to claim 6 , wherein the film is a shrink film.

8. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a melt strength of 10 cN or greater, measured at 190° C.

9. The polyethylene composition according to claim 1 , wherein the polyethylene composition is produced utilizing a chromium oxide catalyst.

10. The polyethylene composition according to claim 1 , wherein the polyethylene composition has a ratio of the z-average molecular weight to the weight average molecular weight (Mz/Mw) of from 4.0 to less than 5.

Assignees

• Dow Global Technologies Llc

Inventors

• Kapur Mridula
• Davis Mark B

Classifications

• C08F210/02 Primary

  Ethene · CPC title

• C08F2500/04

  Broad molecular weight distribution, i.e. Mw/Mn > 6 · CPC title

• C08F210/16 Primary

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• C08F2500/26

  Use as polymer for film forming · CPC title

• C08F2500/12

  Melt flow index or melt flow ratio · CPC title