Processes to improve reactor stability for the preparation of ethylene-based polymers using asymmetrical polyenes

Patent metadata

Field	Value
Publication number	US-9751964-B2
Application number	US-201415101347-A
Country	US
Kind code	B2
Filing date	Dec 23, 2014
Priority date	Dec 26, 2013
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

The invention provides a process to form an ethylene-based polymer, said process comprising polymerizing ethylene and at least one asymmetrical polyene, comprising an “alpha, beta unsaturated—carbonyl end” and a “C—C double bond end,” and wherein the polymerization takes place in the presence of at least one free-radical initiator, and wherein the polymerization takes place in a reactor configuration comprising at least two reaction zones, reaction zone I and reaction zone i (i>2), wherein reaction zone I is downstream from reaction zone I; and wherein at least one chain transfer agent (CTA) is added to the polymerization, and wherein the CTA is a saturated hydrocarbon or an unsaturated hydrocarbon.

First claim

The invention claimed is:

1. A process to form an ethylene-based polymer, said process comprising polymerizing ethylene and at least one asymmetrical polyene, comprising an “alpha, beta unsaturated—carbonyl end” and a “C—C double bond end,” and
wherein the polymerization takes place in the presence of at least one free-radical initiator, and wherein the polymerization takes place in a reactor configuration comprising at least two reaction zones, reaction zone 1 and reaction zone i (i≧2), wherein reaction zone i is downstream from reaction zone 1; and
wherein at least one chain transfer agent (CTA) is added to the polymerization, and wherein the CTA is a saturated hydrocarbon or an unsaturated hydrocarbon.

2. The process of claim 1 , wherein the CTA is selected from an alkane, an alkene, or a combination thereof.

3. The process of claim 1 , wherein the polyene is subject to an “oxygen removal step” prior to being fed to a reaction zone.

4. The process of claim 1 , wherein the polyene is stored in a feed vessel, and wherein the feed vessel has a “head-space gas” comprising less than 5.0 volume percent oxygen.

5. The process of claim 1 , wherein the polyene is fed through a compression stage directly into the reaction zone or directly into the feed to the reaction zone.

6. The process of claim 1 , wherein the polyene is fed directly into the reaction zone or directly into the feed to the reaction zone.

7. The process of claim 1 , wherein the maximum temperature of the first reaction zone is greater than the maximum temperature of each consecutive reaction zone, downstream from the first reaction zone.

8. The process of claim 1 , wherein the maximum temperature of the last reaction zone is less than the maximum temperature of each prior reaction zone.

9. The process of claim 1 , wherein no polyene is fed to reaction zone 1.

10. The process of claim 1 , wherein more polyene is added to reaction zone i, as compared to the amount of polyene added to reaction zone 1.

11. The process of claim 1 , wherein the ethylene fed to the first reaction zone is from 10 to 100 percent of the total ethylene fed to the polymerization.

12. The process of claim 1 , wherein the process takes place in a reactor configuration that comprises at least one tubular reactor.

13. The process of claim 1 , wherein the asymmetrical polyene is selected from the group consisting of the following i) through x):

wherein n is from 1 to 50; Ra is selected from H or alkyl; Rb is selected from H or alkyl;

where m=1 to 20.

Assignees

• Dow Global Technologies Llc

Inventors

• Eddy Christopher R
• Osby John O
• Ewart Sean W
• Munjal Sarat
• Hinrichs Stefan
• Berbee Otto J

Classifications

• C08F210/02 Primary

  Ethene · CPC title

• C08L23/08

  Copolymers of ethene (C08L23/16 takes precedence) · CPC title

• C08F2/38

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

• C08F2220/282

  Chemistry & Metallurgy · mapped topic

• C08F2220/281

  Chemistry & Metallurgy · mapped topic