Polyethylene composition for a film layer

Patent metadata

Field	Value
Publication number	US-10385194-B2
Application number	US-201515527993-A
Country	US
Kind code	B2
Filing date	Nov 18, 2015
Priority date	Nov 26, 2014
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

The present invention relates to a polymer composition, to the use of the polymer composition in film applications and to a film comprising the polymer composition of the invention.

First claim

The invention claimed is:

1. A polymer composition comprising:
(a) a multimodal polymer of ethylene with at least two different comonomers selected from alpha-olefins having from 4 to 10 carbon atoms,
which has
a) a melt flow rate MFR 2 of 0.5 to 10 g/10 min (according to ISO 1133 at 190° C. under 2.16 kg load),
b) a melt flow ratio MFR 21 /MFR 2 of 13 to 30 (MFR 21 at 190° C. under 21.6 kg load), and
c) a molecular weight distribution MWD defined by the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), determined by Gel Permeation Chromatography (GPC), of 5 or less;
wherein:
the multimodal polymer of ethylene (a) comprises at least
an ethylene polymer component (A) and
an ethylene polymer component (B),
the MFR 2 of the ethylene polymer component (A) is different from the MFR 2 of the ethylene polymer component (B); and
the alpha-olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer component (A) is different from the alpha-olefin comonomer having from 4 to 10 carbon atoms of ethylene polymer component (B).

2. The polymer composition according to claim 1 , wherein the ethylene polymer component (A) has a MFR 2 of 1 to 50 g/10 min.

3. The polymer composition according to claim 1 , wherein the MFR 2 of ethylene polymer component (A) is higher than the MFR 2 of ethylene polymer component (B).

4. The polymer composition according to claim 1 , wherein the alpha-olefin comonomer of the ethylene polymer component (A) is 1-butene and the alpha-olefin comonomer of the ethylene polymer component (B) is 1-hexene.

5. The polymer composition according to claim 1 , wherein the multimodal polymer of ethylene (a) is further multimodal with respect to the comonomer content.

6. The polymer composition according to claim 1 , wherein the ratio of [the amount (mol %) of alpha-olefin comonomer having from 4 to 10 carbon atoms comonomer present in ethylene polymer component (A)] to [the amount (mol %) of at least two alpha-olefin comonomers having from 4 to 10 carbon atoms of the final multimodal polymer of ethylene (a)] is of 0.2 to 0.6.

7. The polymer composition according to claim 1 , wherein the amount (mol %) of alpha-olefin comonomer having from 4 to 10 carbon atoms present in the ethylene polymer component (A) is of 0.03 to 5.0 mol %.

8. The polymer composition according to claim 1 , wherein the multimodal polymer of ethylene (a) is further multimodal with respect to density.

9. The polymer composition according to claim 1 , wherein the density of the ethylene polymer component (A) is of 925 to 950 kg/m 3 .

10. The polymer composition according to claim 1 , wherein the density of the multimodal polymer of ethylene (a) is of 910 to 935 kg/m 3 .

11. The polymer composition according to claim 1 , wherein the multimodal polymer of ethylene (a) has MFR 21 /MFR 2 of 15 to 30.

12. The polymer composition according to claim 1 , wherein the multimodal polymer of ethylene (a) is multimodal with respect to MFR, type of the comonomer, comonomer content and density.

13. The polymer composition according to claim 1 , wherein polymer composition has a the tensile modulus in machine direction (MD) of 200 to 350 MPa when determined according to ISO 527-1 and ISO 527-3 and measured from a film sample (40 μm thickness) consisting of the polymer composition.

14. The polymer composition according to claim 1 , wherein the polymer composition, has a shear thinning index SHI 2.7/210 of 1.5 to 7 when determined according to ISO 6721-1 and ISO 6721-10.

15. The polymer composition according to claim 1 , wherein the multimodal polymer of ethylene (a) is produced using a single site catalyst.

16. An article comprising the polymer composition according to claim 1 .

17. A film comprising at least one layer which comprises the polymer composition according to claim 1 .

Assignees

• Borealis Ag

Inventors

• Kela Jarmo
• Niedersuss Peter
• Aarila Jari
• Vahteri Markku
• Prades Floran
• Jamieson John
• De Wever Willem

Classifications

• C08L2308/00

  Chemical blending or stepwise polymerisation process with the same catalyst · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L2314/06

  Metallocene or single site catalysts · CPC title

• C08F2500/18

  Bulk density · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title