Process for making a cross-linked polyethylene article

Patent metadata

Field	Value
Publication number	US-10173358-B2
Application number	US-201314649939-A
Country	US
Kind code	B2
Filing date	Dec 17, 2013
Priority date	Dec 21, 2012
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A process for for making a cross-linked polyethylene article includes: (A) feeding a blend comprising a cross-linkable silane-group containing polyethylene copolymer and at least one additive to an extruder, (B) feeding a liquid comprising a silanol condensation catalyst to said extruder to form a mixture with said blend, (C) extruding said mixture to form an article and (D) cross-linking said article. The article may be a pipe or cable.

First claim

The invention claimed is:

1. A process for making a cross-linked polyethylene article comprising:
(A) feeding a blend comprising a cross-linkable silane-group containing polyethylene copolymer and at least one additive to an extruder,
(B) feeding a liquid comprising a silanol condensation catalyst to said extruder to form a mixture with said blend,
(C) extruding said mixture to form the article and
(D) cross-linking said article.

2. The process according to claim 1 wherein the blend and the liquid are separately fed to the extruder.

3. The process according to claim 1 wherein the blend and the liquid are premixed before entering the extruder.

4. The process according to claim 1 wherein the at least one additive is an antioxidant.

5. The process according to claim 1 wherein the at least one additive is a scorch retarder.

6. The process according to claim 5 wherein the scorch retarder is a silane-containing compound.

7. The process according to claim 6 wherein the cross-linkable silane-group containing polyethylene copolymer is a copolymer of ethylene and a tri-alkoxy vinyl silane or vinyl tri-methoxy silane.

8. The process according to claim 1 wherein the cross-linkable silane-group containing polyethylene copolymer is formed in a reactor under a pressure of 500 to 4,000 kg/cm 2 .

9. The process according to claim 1 wherein the silanol condensation catalyst comprises a metal and a Lewis acid.

10. The process according to claim 1 wherein the silanol condensation catalyst is dioctyl tin laureate (DOTL) or zirconium acetylacetonate.

11. The process according to claim 1 which is peroxide free.

12. The process according to claim 1 wherein the article is a cable and the extruder is a cable extruder.

13. The process according to claim 1 wherein the blend comprises all the additives of the composition to be formed, except for the silanol condensation catalyst and optionally a drying agent.

14. The process according to claim 1 wherein the liquid consist of the silanol condensation catalyst or the silanol condensation catalyst and a drying agent.

15. The process according to claim 1 further comprising:
forming the blend prior to the feeding.

16. The process according to claim 1 , wherein the blend is in the form of pellets.

17. The process according to claim 1 , wherein the blend is in the form of a powder.

18. The process according to claim 1 , wherein the blend is in the form of a second liquid.

19. The process according to claim 1 , wherein the liquid consists of dioctyl tin laurate.

20. A process for making a cross-linked polyethylene article comprising:
(A) feeding a blend comprising a cross-linkable silane-group containing polyethylene copolymer and at least one additive to an extruder,
(B) feeding a liquid comprising a silanol condensation catalyst to said extruder to form a mixture with said blend,
(C) extruding said mixture to form the article and
(D) cross-linking said article;
wherein the blend is in the form of pellets comprising an ethylene vinyl silane copolymer and vinyl trimethoxy silane.

Assignees

• Borealis Ag

Inventors

• Toullec Thierry
• Laurenson Paul
• Verheule Bart
• Fagrell Ola
• Karlsson Linus

Classifications

• C08F8/42

  Introducing metal atoms or metal-containing groups · CPC title

• B29C47/8895

  Operations & Transport · mapped topic

• B29C47/0014

  Operations & Transport · mapped topic

• B29C47/0009

  Operations & Transport · mapped topic

• C08K5/57

  Organo-tin compounds · CPC title