Multimodal polyethylene container

Patent metadata

Field	Value
Publication number	US-11312792-B2
Application number	US-201716332065-A
Country	US
Kind code	B2
Filing date	Sep 11, 2017
Priority date	Sep 12, 2016
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

The present invention relates to a reactor system for a multimodal polyethylene polymerization process, comprising; (a) a first reactor; (b) a hydrogen removal unit arranged between the first reactor and a second reactor comprising at least one vessel connected with a depressurization equipment, preferably selected from vacuum pump, compressor, blower, ejector or a combination thereof, the depressurization equipment allowing to adjust an operating pressure to a pressure in a range of 100-200 kPa (abs); (c) the second reactor; and (d) a third reactor and the use thereof as a container.

First claim

The invention claimed is:

1. A process for producing a multimodal polyethylene composition in a reactor system comprising:
(a1) a first reactor having a catalyst system selected from Ziegler-Natta catalyst or metallocene;
(b1) a hydrogen removal unit arranged between the first reactor and a second reactor, said hydrogen removal unit comprising at least one vessel connected with depressurization equipment selected from a vacuum pump, a compressor, a blower, an ejector or a combination thereof, the depressurization equipment configured to adjust an operating pressure to a pressure in a range of 103-145 kPa (abs);
(c1) the second reactor; and
(d1) a third reactor,
the process comprising:
(a2) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of the catalyst system and hydrogen in an amount of 0.1-95% by mole with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene having a weight average molecular weight (Mw) of 20,000 to 90,000 g/mol or medium molecular weight polyethylene having a weight average molecular weight (Mw) of more than 90,000 to 150,000 g/mol wherein the low molecular weight polyethylene, respectively the medium molecular weight polyethylene, has a density at least 0.965 g/cm3, and the low molecular weight polyethylene has MI2 in the range from 10 to 1,000 g/10 min and the medium molecular weight polyethylene has MI2 in the range from 0.1 to 10 g/10 min;
(b2) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen comprised in a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor;
(c2) polymerizing ethylene and optionally C 4-12 α-olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b2) to obtain a first high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol and transferring a resultant mixture to the third reactor; and
(d2) polymerizing ethylene, and optionally C 4-12 α-olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 0.1-70% by mol, with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or a second ultra high molecular weight polyethylene homopolymer or copolymer having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol.

2. The process according to claim 1 , wherein the pressure in the hydrogen removal unit is in the range of 105 to 115 kPa (abs).

3. The process according to claim 1 , wherein the hydrogen removal unit further comprises a stripping column for the separation of the hydrogen in the slurry mixture from a liquid diluent.

4. The process of claim 1 , wherein the amount of hydrogen in the third reactor is in a range of 0.1-60% by mol.

5. The process according to claim 1 , wherein the removing is removing of 98.0-99.5% by weight of the hydrogen.

6. The process according to claim 5 , wherein the pressure in the hydrogen removal unit is in the range of 105 to 115 kPa (abs).

7. A multimodal polyethylene composition comprising:
(A) 30 to 65 parts by weight of a low molecular weight polyethylene having a weight average molecular weight (Mw) of 20,000 to 90,000 g/mol;
(B) 10 to 40 parts by weight of a first high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or a first ultra high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol; and
(C) 10 to 50 parts by weight of a second high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or a second ultra high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol,
wherein the multimodal polyethylene composition has a FNCT at 80° C., 3.5 MPa with the environment of 2% solution of 4-nonylphenyl-polyethylene glycol from 10 to 270 hours, and
wherein (A), (B), and (C) each have a different weight average molecular weight.

8. The multimodal polyethylene composition according to claim 7 , wherein the multimodal polyethylene composition has a swelling ratio at shear rate 1400 1/sec determined at temperature of 190° C. in a circular length 0.25 mm orifice die 2 mm diameter and entrance angle by 45° of at least 170%.

9. The multimodal polyethylene composition according to claim 7 , wherein the FNCT at 80° C., 3.5 MPa with the environment of 2% solution of 4-nonylphenyl-polyethylene glycol is from 12 to 250 hours.

10. The multimodal polyethylene composition according to claim 7 , wherein the multimodal polyethylene composition has a weight average molecular weight from 150,000 to 500,000 g/mol, measured by Gel Permeation Chromatography.

11. The multimodal polyethylene composition according to claim 10 , wherein the weight average molecular weight is from 200,000 to 400,000 g/mol.

12. The multimodal polyethylene composition according to claim 7 , wherein the multimodal polyethylene composition has a number average molecular weight from 8,000 to 25,000 g/mol, measured by Gel Permeation Chromatography.

13. The multimodal polyethylene composition according to claim 7 , wherein the multimodal polyethylene composition has a Z average molecular weight from 1,000,000 to 5,000,000 g/mol, measured by Gel Permeation Chromatography.

14. The multimodal polyethylene composition according to claim 7 wherein the multimodal polyethylene composition has a density from 0.940 to 0.966 g/cm 3 , according to ASTM D 1505 and/or MI 5 from 0.01 to 7 g/10 min, and/or MI 21 from 0.2 to 130 g/10 min.

15. A container comprising the multimodal polyethylene composition according to claim 7 .

16. The container according to claim 15 , obtained by blow molding, sheet forming or thermoforming.

17. The container according to claim 15 , wherein the container has a volumetric capacity of 0.25 L to 40 L.

18. The container according to claim 15 , wherein the container has a volumetric capacity of 40 L to 500 L.

19. The container according to claim 15 , wherein the container has a volumetric capacity of 500 L to 2,000 L.

20. A multimodal polyethylene composition comprising:
(A) 40 to 65 parts by weight of a low molecular weight polyethylene having a weight average molecular weight (Mw) of 20,000 to 90,000 g/mol;
(B) 10 to 40 parts by weight of a first high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 150,000 to 1,000,000 g/mol or a first ultra high molecular weight polyethylene having a weight average molecular weight (Mw) of more than 1,000,000 to 5,000,000 g/mol; and
(C) 10 to 50 parts by weight of a second high molecular weight polyethylene having a weight average molecular weight (

Assignees

• Thai Polyethylene Co Ltd
• Scg Chemicals Co Ltd

Inventors

• Suk-Em Chatdao
• Suchao-In Natthaporn
• Cheevasrirungruang Watcharee
• Klomkamol Warachad
• Thitisak Boonyakeat

Classifications

• C08L2207/068

  Ultra high molecular weight polyethylene · CPC title

• B29D22/003

  Containers for packaging, storing or transporting, e.g. bottles, jars, cans, barrels, tanks · CPC title

• C08L23/0815

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

• C08L2203/10

  used for bottles · CPC title

• C08F2400/02

  Control or adjustment of polymerization parameters · CPC title