Polyolefin pipe

Patent metadata

Field	Value
Publication number	US-10519286-B2
Application number	US-201515304597-A
Country	US
Kind code	B2
Filing date	Apr 22, 2015
Priority date	Apr 23, 2014
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

This invention relates to a polymeric pipe, and more particularly a polymeric pipe where the pipe comprises a crosslinked polyolefin formed from extruded polyolefin comprising a photoinitiator. More particularly, this invention relates to the manufacturing of plastic pipes and tubing by utilizing co-rotating twin screw extrusion combined with photo-induced cross-linking, of thermoplastic polymers such as polyethylene, to produce PEX pipes and tubing.

First claim

The invention claimed is:

1. A polymeric pipe formed from:
a polyolefin structural polymer; and
a photoinitiator in an amount of 0.02 to 3% by weight,
wherein the photoinitiator is a compound of formula I:

wherein:
R 1 is selected from the group consisting of —C 4 -C 24 alkyl, —(CH 2 ) m (C 2 -C 24-m alkenyl), —(CH 2 ) m (C 2 -C 24-m alkynyl), —C 4 -C 24 haloalkyl, —(CH 2 ) m (C 2 -C 24-m haloalkenyl), —(CH 2 ) m (C 2 -C 24-m haloalkynyl), and —(CH 2 ) n [O(CH 2 ) p ] q (CH 2 ) r R 4 ;
R 2 is selected from the group consisting of —H and —O—R 3 ;
R 3 is selected from the group consisting of —C 4 -C 24 alkyl, —(CH 2 ) m (C 2 -C 24-m alkenyl), —(CH 2 ) m C 2 -C 24-m alkynyl), —C 4 -C 24 haloalkyl, —(CH 2 ) m (C 2 -C 24-m haloalkenyl), —(CH 2 ) m (C 2 -C 24-m haloalkynyl), and —(CH 2 ) n [O(CH 2 ) p ] q (CH 2 ) r R 5 ;
R 4 and R 5 are independently selected from the group consisting of —H and —O—R 6 ;
R 6 is selected from the group consisting of —H, —C 1 -C 18 alkyl, —(CH 2 ) s (C 2 -C 18-s alkenyl), and —(CH 2 ) s (C 2 -C 18-s alkynyl);
m is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 or 22;
n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;
p is 2, 3, 4, 5 or 6;
q is 2, 3, 4, 5, 6, 7, 8, 9, or 10;
r is 0, 1 or 2;
s is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16; and
wherein when R 2 is —H, R 1 comprises at least 7 carbon atoms.

2. The pipe of claim 1 , wherein the polyolefin structural polymer is selected from the group consisting of polyethylene, polypropylene, polybutylene, and any copolymers of two or more of polyethylene, polypropylene and polybutylene.

3. The pipe of claim 1 , wherein R 1 is —C 4 -C 24 alkyl or —C 4 -C 24 haloalkyl.

4. The pipe of claim 1 , wherein R 1 is —C 8 -C 20 alkyl.

5. The pipe of claim 1 , wherein R 1 is —(CH 2 ) m (C 2 -C 24-m alkenyl) or —(CH 2 ) m (C 2 -C 24-m alkynyl).

6. The pipe of claim 1 , wherein R 1 is C 8 , C 10 , C 12 , C 14 , C 16 or C 18 alkyl.

7. The pipe of claim 1 , wherein R 2 is —H.

8. The pipe of claim 1 , wherein R 2 is —O—R 3 .

9. The pipe of claim 8 , wherein R 1 and R 3 are the same.

10. The pipe of claim 8 , wherein R 1 and R 3 are both C 4 , C 5 , C 6 , C 7 or C 8 alkyl.

11. The pipe of claim 1 , wherein the photoinitiator comprises at least two compounds of formula I.

12. The pipe of claim 1 , wherein the photoinitiator is in an amount of 0.3 to 1.5% by weight.

13. The pipe of claim 1 , wherein the pipe further comprises a co-agent in an amount of 0.02-10% by weight, wherein the co-agent comprises at least one reactive carbon-carbon double bond.

14. The pipe of claim 13 , wherein the co-agent is selected from or comprises acrylates, methacrylates, polybutadienes, allyl ethers, vinyl ethers and mono or polyunsaturated oils.

15. The pipe of claim 13 , wherein the co-agent comprises at least one of triallylcyanurate, a polybutadiene or trimethylolpropane triacrylate (TMPTA).

16. The pipe of claim 1 , further comprising a hindered amine light stabiliser in an amount of 0.05 to 1% by weight.

17. The pipe of claim 16 , wherein the hindered amine light stabiliser comprises:

wherein R 5 is a C 2 -C 24 alkyl group.

18. The pipe of claim 1 , further comprising an antioxidant in an amount of 0.1 to 1% by weight.

19. The pipe of claim 18 , wherein the antioxidant comprises

or a combination thereof.

20. The pipe of claim 1 , wherein the pipe is a cross-linked polyolefin pipe with the characteristics of a pipe obtainable by:
extrusion of a mixture comprising the polyolefin structural polymer and photoinitiator from a co-rotating twin screw extruder to form an extruded pipe; and
cross-linking the structural polymer by irradiating the extruded pipe with UV radiation.

21. The pipe of claim 20 , wherein the degree of crosslinking is in the range of about 60% to about 90%.

22. The pipe of claim 1 , wherein, when tested in accordance with NSF 61, the level of residuals of the following compounds are at the specified level:
benzene is less than or equal to 5 ppb,
benzophenone is less than or equal to 30 ppb,
benzhydrol is less than or equal to 50 ppb,
p-hydroxybenzophenone is less than or equal to 10 ppb,
p-hydroxybenzhydrol is less than or equal to 10 ppb, and
p-formylbenzophenone is less than or equal to 10 ppb.

23. A method of producing a cross-linked polyolefin pipe comprising:
extrusion of a mixture from a co-rotating twin screw extruder to form an extruded pipe; and
cross-linking a polyolefin structural polymer by irradiating the extruded pipe with UV radiation,
wherein the extrusion mixture comprises the polyolefin structural polymer and a photoinitiator in an amount of 0.02 to 3% by weight;
wherein the photoinitiator is a compound of formula I:

wherein:

R 1 is selected from the group consisting of —C 4 -C 24 alkyl, —(CH 2 ) m (C 2 -C 24-m alkenyl), —(CH 2 ) m (C 2 -C 24-m alkynyl), —C 4 -C 24 haloalkyl, —(CH 2 ) m (C 2 -C 24-m haloalkenyl), —(CH 2 ) m (C 2 -C 24-m haloalkynyl), and —(CH 2 ) n [O(CH 2 ) p ] q (CH 2 ) r R 4 ;
R 2 is selected from the group consisting of —H and —O—R 3 ;
R 3 is selected from the group consisting of —C 4 -C 24 alkyl, —(CH 2 ) m (C 2 -C 24-m alkenyl), —(CH 2 ) m (C 2 -C 24-m alkynyl), —C 4 -C 24 haloalkyl, —(CH 2 ) m (C 2 -C 24-m haloalkenyl), —(CH 2 ) m (C 2 -C 24-m haloalkynyl), and —(CH 2 ) n [O(CH 2 ) p ] q (CH 2 ) r R 5 ;
R 4 and R 5 are independently selected from the group consisting of —H and —O—R 6 ;
R 6 is selected from the group consisting of —H, —C 1 -C 18 alkyl, —(CH 2 ) s (C 2 -C 18-s alkenyl), and —(CH 2 ) s (C 2 -C 18-s alkynyl);
m is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 or 22;
n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12;
p is 2, 3, 4, 5 or 6;
q is 2, 3, 4, 5, 6, 7, 8, 9 or 10;
r is 0, 1 or 2;
s is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16; and
wherein when R 2 is —H, R 1 comprises at least 7 carbon atoms.

24. The method of claim 23 , wherein the polyolefin structural polymer is selected from the group consisting of polyethylene, polypropylene, polybutylene, and any copolymers of two or more of polyethylene, polypropylene and polybutylene.

25. The method of claim 23 , wherein the mixture further comprises a co-agent in an amount of 0.02-10% by weight, wherein the co-agent comprises at least one reactive carbon-carbon double bond.

26. The method of claim 23 , wherein the mixture further comprises a hindered amine light stabiliser in an amount of 0.05 to 1% by weight.

27. The method of claim 23 , wherein the mixture further comprises an antioxidant in an amount of 0.1 to 1% by weight.

28. The method of claim 23 , wherein the cross-linked polyolefin pipe has a degree

Assignees

• Uponor Innovation Ab

Inventors

• Ericsson Jan
• Menssen Todd

Classifications

• C08K5/07

  Aldehydes; Ketones · CPC title

• C08K5/3435

  Piperidines · CPC title

• C08K5/105

  with phenols · CPC title

• C08J3/24 Primary

  Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K) · CPC title

• C08J3/28 Primary

  Treatment by wave energy or particle radiation · CPC title