Polyolefin Compositions and Articles Thereof

Patent metadata

Field	Value
Publication number	US-2023220136-A1
Application number	US-202118001439-A
Country	US
Kind code	A1
Filing date	Jun 10, 2021
Priority date	Jul 22, 2020
Publication date	Jul 13, 2023
Grant date	—

Abstract

In some embodiments, a polyethylene composition includes has 80 wt % to 99.9 wt % ethylene content and 20 wt % to 0.1 wt % a C3 to C40 α-olefin comonomer content, based on ethylene content plus comonomer content. The composition has a Mw/Mn of 15 to 45, a density of 0.93 g/cm3 to 0.97 g/cm3, a complex viscosity (at 628 rad/s, 190° C.) of 600 Pa*s or less, a zero shear viscosity by Cross model of 150,000 Pa*s to 350,000 Pa*s. It may also have a V index of less than 7. In some embodiments, an article includes the polyethylene composition. In some embodiments, the article is a pipe.

First claim

We claim:

1 . A polyethylene composition comprising:
80 wt % to 99.9 wt % ethylene content, and 20 wt % to 0.1 wt % a C 3 to C 12 α-olefin comonomer content, each based on ethylene content plus C 3 to C 12 α-olefin comonomer content; the polyethylene composition having:
an Mw/Mn of 20 to 45;
a density of 0.93 g/cm 3 to 0.97 g/cm 3 ;
a complex viscosity (at 628 rad/s, 190° C.) of 600 Pa*s or less;
a Cross model zero shear viscosity of 150,000 Pa*s to 350,000 Pa*s; and
a V index of less than 7.

2 . The polyethylene composition of claim 1 , wherein:
the ethylene content is 98.5 wt % to 99.5 wt %, and the comonomer content 1.5 wt % to 0.5 wt %.

3 . The polyethylene composition of claim 1 , wherein the C 3 to C 12 α-olefin comonomer is 1-butene.

4 . The polyethylene composition of claim 1 , wherein the polyethylene composition has one or more of the following properties:
(a) a weight average molecular weight (Mw) of 40,000 g/mol to 1,500,000 g/mol; (b) a number average molecular weight (Mn) of 3,000 g/mol to 100,000 g/mol; (c) Mw/Mn of 25 to 40; (d) a Z-average molecular weight (Mz) of 1,000,000 g/mol to 3,000,000 g/mol; (e) Mz/Mw of 5.5 to 8; (f) g′ of 0.6 to 0.8; (g) melt index (I 2 ) of 0.01 g/10 min to 0.50 g/10 min; (h) high load meld index (I 21 ) of 0.01 g/10 min to 100 g/10 min; and (i) melt index ratio (MIR, I 21 /I 2 ) of 100 to 2005.

5 . The polyethylene composition of claim 4 , having all of the properties (a)-(i).

6 . The polyethylene composition of claim 4 , wherein the polyethylene composition has one or more of the following properties:
(a1) Mw of 300,000 g/mol to 320,000 g/mol; (b1) Mn of 10,000 g/mol to 15,000 g/mol; (c1) Mw/Mn of 26 to 32; (d1) Mz of 1,800,000 g/mol to 1,960,000 g/mol; (e1) Mz/Mw of 6 to 6.5; (f1) g′ of 0.7 to 0.76 (g1) I 2 of 0.03 g/10 min to 0.12 g/10 min; (h1) I 21 of 5 g/10 min to 10 g/10 min; and (i1) MIR of 135 to 145.

7 . The polyethylene composition of claim 6 , having all of the properties (a1)-(i1).

8 . The polyethylene composition of claim 1 , wherein the polyethylene composition has a density of 0.945 g/cm 3 to 0.955 g/cm 3 .

9 . The polyethylene composition of claim 1 , wherein the polyethylene composition has one or more of the following properties:
(j) complex viscosity (at 628 rad/s, 190° C.) of 525 Pa*s to 575 Pa*s; (k) Cross model zero shear viscosity (at 1 rad/s, 190° C.) of 200,000 Pa*s to 400,000 Pa*s; (l) Notched Constant Ligament-Stress (NCLS) value of greater than 800 hours; (m) K factor of 0.2 to 0.5; and (n) V index of −30 to 0.

10 . The polyethylene composition of claim 9 , having all of the properties (j)-(n).

11 . The polyethylene composition of claim 9 , having NCLS value of greater than 1500 hours.

12 . The polyethylene composition of claim 9 , having Cross model zero shear viscosty (at 1 rad/s, 190° C.) of 200,000 Pa*s to 275,000 Pa*s.

13 . The polyethylene composition of claim 9 , having Cross model zero shear viscosity (at 1 rad/s, 190° C.) of 300,000 Pa*s to 350,000 Pa*s.

14 . The polyethylene composition of claim 1 , wherein the polyethylene composition has a multimodal molecular weight distribution.

15 . The polyethylene composition of claim 14 , wherein the polyethylene composition comprises:
a low molecular weight fraction (LMWF) having a GPC average molecular weight distribution with an Mw value of 10,000 g/mol to about 100,000 g/mol, a Mn value of 3,000 g/mol to about 10,000 g/mol, a Mz value of about 200,000 g/mol to about 800,000, Mw/Mn of 4.0 to 12.0, and a density of about 0.930 g/cm 3 to about 0.980 g/cm 3 ; and a high molecular weight fraction (HMWF).

16 . The polyethylene composition of claim 14 , wherein the LMWF has Mw/Mn of 5 to 10, an Mn value of 3,000 to 10,000, and an Mz value greater than 300,000.

17 . The polyethylene composition of claim 14 , wherein the LMWF comprises 49 wt % to 51 wt % of the polyethylene composition and the HMWF comprises 51 wt % to 49 wt % of the polyethylene composition, based on the total of HMWF+LMWF where the total of HMWF+LMWF does not exceed 100%.

18 . The polyethylene composition of claim 14 , wherein the HMWF has a lower density than the LMWF.

19 . A polyethylene composition comprising:
80 wt % to 99.9 wt % ethylene content and 20 wt % to 0.1 wt % a C 3 to C 40 α-olefin comonomer content, each based on ethylene content plus comonomer content, the polyethylene composition having:
an Mw/Mn of 15 to 45;
a density of 0.93 g/cm 3 to 0.97 g/cm 3 ;
an HLMI of 5 to 9 g/10 mins; and
a complex viscosity (at 628 rad/s, 190° C.) of 600 Pa*s or less.

20 . The polyethylene composition of claim 19 , wherein the polyethylene composition has one or more of the following properties:
(a) a weight average molecular weight (Mw) of 40,000 g/mol to 1,500,000 g/mol; (b) a number average molecular weight (Mn) of 3,000 g/mol to 100,000 g/mol; (c) Mw/Mn of 25 to 40; (d) a Z-average molecular weight (Mz) of 1,000,000 g/mol to 3,000,000 g/mol; (e) Mz/Mw of 5.5 to 8; (f) g′ of 0.6 to 0.8; (g) melt index (I 2 ) of 0.01 g/10 min to 0.50 g/10 min; (h) high load meld index (I 21 ) of 0.01 g/10 min to 100 g/10 min; and (i) melt index ratio (MIR, I 21 /I 2 ) of 100 to 2005.

21 . An article comprising the polyethylene composition of any one of the foregoing claims.

22 . The article of claim 21 , wherein the article is a pipe.

23 . The article of claim 22 , wherein the pipe has one or both of the following properties: (i) a slow crack growth of 3,000 hours or greater; and (ii) a long term hydrostatic strength (LTHS) (100,000 hours, 20° C.) of 10 MPa to 12 MPa.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Peng Haiqing
• Guerra Jorge A
• Nguyen Danica L
• Kang Shuhui
• Mouton Trent J
• Pham Truyen T

Classifications

• C08L23/0815 Primary

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• C08F210/16 Primary

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

• C08L2203/18

  used for pipes · 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

• F16L9/12

  of plastics with or without reinforcement (F16L9/16 - F16L9/22 take precedence) · CPC title