Polymerization Process to Make Low Density Polyethylene

Patent metadata

Field	Value
Publication number	US-2016115256-A1
Application number	US-201514980701-A
Country	US
Kind code	A1
Filing date	Dec 28, 2015
Priority date	Sep 30, 2010
Publication date	Apr 28, 2016
Grant date	—

Abstract

A high pressure polymerization process to form an ethylene-based polymer comprises the steps of:
A. Injecting a first feed comprising a chain transfer agent system (CTA system) and ethylene into a first autoclave reactor zone operating at polymerization conditions to produce a first zone reaction product, the CTA system of the first reactor zone having a transfer activity Z1; and B. (1) Transferring at least part of the first zone reaction product to a second reactor zone selected from a second autoclave reactor zone or a tubular reactor zone and operating at polymerization conditions, and, optionally, (2) freshly injecting, a second feed into the second reactor zone to produce a second zone reaction product, with the proviso that at least one of the first reactor zone product and the freshly injected feed comprises a CTA system with a transfer activity of Z2; and

with the proviso that the ratio of Z1:Z2 is greater than 1.

First claim

1 . A high pressure polymerization process to form an ethylene-based polymer, the process comprising the steps of:
A. Injecting a first feed comprising a chain transfer agent system (CTA system) and ethylene into a first autoclave reactor zone operating at polymerization conditions to produce a first zone reaction product, the CTA system of the first reactor zone having a transfer activity Z1; and B. (1) Transferring at least part of the first zone reaction product to a second reactor zone selected from a second autoclave reactor zone or a tubular reactor zone and operating at polymerization conditions, and, (2) freshly injecting, a second feed comprising fresh ethylene without a CTA into the second reactor zone to produce a second zone reaction product comprises a CTA system with a transfer activity of Z2; and
with the proviso that the ratio of Z1:Z2 is greater than 1.

2 . The process of claim 1 , further comprising one or more steps of transferring a zone reaction product produced in an (ith−1) reaction zone to an (ith) reaction zone, where 3≦i≦n, and n≧3, each zone operating at polymerization conditions, and optionally adding an (ith) feed comprising a CTA system into the (ith) reaction zone, the CTA system of the (ith) reaction zone having a transfer activity of Zi with the proviso that the ratio of Z1/Zi is greater than 1.

3 . (canceled)

4 . The process of claim 1 , in which at least part of the first zone reaction product is transferred to a second autoclave reactor zone.

5 . The process of claim 1 , in which at least part of the first zone reaction product is transferred to a tubular reactor zone.

6 . (canceled)

7 . The process of claim 1 , in which at least one CTA has a chain transfer constant Cs greater than 0.003.

8 . The process of claim 1 in which each of the polymerization conditions in the reactor zones, independently, comprises a temperature greater than, or equal to, 100° C., and a pressure greater than, or equal to, 100 MPa.

9 . The process of claim 2 in which the ratio Z1/Z2 and each ratio Z1/Zi are greater than 1.03.

10 . The process of claim 2 in which the ratio Z1/Z2 and each ratio Z1/Zi are less than 10.

11 . An ethylene-based polymer made by a process of claim 1 .

12 . The ethylene-based polymer of claim 11 further comprising a density from 0.926 to 0.94 g/cm 3 , and a melt index of 0.2 to 5 g/10 min.

13 . The ethylene-based polymer of claim 12 in which the polymer is a polyethylene homopolymer.

14 . The ethylene-based polymer of claim 12 in which the polymer is an ethylene-based interpolymer.

15 . A composition comprising the ethylene-based polymer of claim 11 .

16 . An article comprising at least one component comprising the ethylene-based polymer of claim 11 .

17 . (canceled)

18 . (canceled)

19 . (canceled)

Assignees

• Dow Global Technologies Llc

Inventors

• Berbee Otto J
• De Doelder Cornelis F J
• Hosman Cornelis J

Classifications

• C08F10/02 Primary

  Ethene · CPC title

• C08F210/02

  Ethene · CPC title

• C08F110/02

  Ethene · CPC title

• C08F2/01

  characterised by special features of the polymerisation apparatus used · CPC title

• C08F2/38

  Polymerisation using regulators, e.g. chain terminating agents {, e.g. telomerisation} · CPC title