Liquid injection barrel element for barrel extruder

Patent metadata

Field	Value
Publication number	US-11090848-B2
Application number	US-201916370223-A
Country	US
Kind code	B2
Filing date	Mar 29, 2019
Priority date	Mar 29, 2019
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

Described herein is a liquid injector for a barrel extruder as well as methods and processes of manufacturing irradiation crosslinked polypropylene foam. In some embodiments, this includes a liquid injection barrel element that is incorporated in an extruder barrel that includes at least one injection port, a temperature sensor well, and cooling channels.

First claim

The invention claimed is:

1. A barrel element for a barrel extruder comprising:
a body having an interior opening extending through a width of the body in a direction of an axial length of the barrel extruder, wherein the width of the body is 20-60 mm and wherein the body comprises:
at least one injection port extending from a first external side of the body to the interior opening;
a temperature sensor well extending from the first external side of the body towards the interior opening;
a cooling inlet channel extending from a second external side of the body, opposite the first external side of the body, in a first direction;
a cooling outlet channel extending from the second external side of the body in the first direction; and
a plurality of connecting cooling channels extending in a second direction, wherein the cooling inlet channel and the cooling outlet channel are fluidly connected by the plurality of connecting cooling channels.

2. The barrel element of claim 1 , wherein the at least one injection port is fluidly connected between the first external side of the body and the interior opening.

3. The barrel element of claim 1 , wherein the at least one injection port extends from the first external side of the body in a direction that is perpendicular to a tangent of an outer perimeter of the interior opening.

4. The barrel element of claim 1 , wherein the body comprises a second injection port extending from the first external side of the body to the interior opening.

5. The barrel element of claim 4 , wherein the second injection port is fluidly connected between the first external side of the body and the interior opening.

6. The barrel element of claim 1 , wherein a distal end of the temperature sensor well is closed.

7. The barrel element of claim 6 , wherein the distal end of the temperature sensor well is adjacent to an outlet of the at least one injection port.

8. The barrel element of claim 1 , wherein the cooling inlet channel and the cooling outlet channel are parallel.

9. The barrel element of claim 1 , wherein the cooling inlet channel and the cooling outlet channel are on opposite sides of the interior opening.

10. The barrel element of claim 1 , wherein the plurality of connecting cooling channels are perpendicular to the cooling inlet channel and/or cooling outlet channel.

11. The barrel element of claim 1 , wherein the cooling inlet channel extends towards the first external side of the body.

12. The barrel element of claim 1 , wherein the cooling outlet channel extends towards the first external side of the body.

13. The barrel element of claim 1 , wherein the plurality of connecting cooling channels comprises a first group of connecting cooling channels and a second group of connecting cooling channels.

14. The barrel element of claim 13 , wherein the first group of connecting cooling channels and the second group of connecting cooling channels are on opposite sides of the interior opening.

15. A method of manufacturing an extruded structure, comprising:
introducing resin into a feeder of an extruder;
introducing a liquid crosslinking agent into the extruder through a barrel element at a location downstream of the feeder, wherein the barrel element comprises:
a body having an interior opening extending through a width of the body in a direction of an axial length of the barrel extruder, wherein the width of the body is 20-60 mm and wherein the body comprises:
at least one injection port extending from a first external side of the body to the interior opening;
a temperature sensor well extending from the first external side of the body towards the interior opening;
a cooling inlet channel extending from a second external side of the body, opposite the first external side of the body, in a first direction;
a cooling outlet channel extending from the second external side of the body in the first direction; and
a plurality of connecting cooling channels extending in a second direction, wherein the cooling inlet channel and the cooling outlet channel are fluidly connected by the plurality of connecting cooling channels;

introducing a chemical blowing agent into the extruder at a location downstream of the location where the liquid crosslinking agent is introduced into the extruder; and
extruding a structure from the extruder.

16. The method of claim 15 , further comprising irradiating the extruded structure to produce a crosslinked extruded structure.

17. The method of claim 16 , further comprising foaming the crosslinked extruded structure to produce a foam structure.

18. The method of claim 17 , wherein the foaming includes pre-heating the crosslinked extruded structure.

19. The method of claim 18 , wherein the foaming includes using a salt bath as a heat source to activate the chemical blowing agent in the crosslinked extruded structure.

20. The method of claim 17 , wherein the foaming includes using at least one of a radiant heater, a hot air oven, or microwave energy as a heat source to activate the chemical blowing agent in the crosslinked extruded structure.

21. The method of claim 15 , wherein the chemical blowing agent is introduced into the extruder through a side stuffer downstream of a location where the liquid crosslinking agent is introduced into the extruder.

22. The method of claim 15 , wherein the resin introduced into the feeder has a non-powder form.

23. The method of claim 22 , wherein the resin is formed as pellets, granules, chips, flakes, beads, cylinders, or tubes.

24. The method of claim 23 , wherein the resin comprises a polypropylene based polymer comprising homopolymer polypropylene, MAH-g-polypropylene, impact modified polypropylene, polypropylene-ethylene copolymer, MAH-g-polypropylene-ethylene copolymer, metallocene polypropylene, metallocene polypropylene-ethylene copolymer, metallocene polypropylene olefin block copolymer with a controlled block sequence, polypropylene based polyolefin plastomer, polypropylene based polyolefin elasto-plastomer, polypropylene based polyolefin elastomer, polypropylene based thermoplastic polyolefin blend and polypropylene based thermoplastic elastomeric blend.

25. The method of claim 15 , wherein the extruded structure has a sheet-like profile and is at least one of a film, a web or a sheet.

26. The method of claim 15 , wherein the extruding is performed with a co-rotating, twin screw extruder.

27. The method of claim 26 , wherein the extruder has a length to screw diameter ratio of 36:1 to 52:1.

28. The method of claim 26 , wherein the extruder has a length greater than 20 screw diameters.

29. The method of claim 28 , wherein the feeder is located within an initial 4 screw diameters, the liquid crosslinking agent is introduced into the barrel element within 4 to 8 screw diameters and the blowing agent is introduced into the extruder within 16 to 20 screw diameters.

30. The method of claim 27 , wherein each twin screw has a diameter of 27 to 135 mm.

31. The method of claim 15 , wherein a temperature within the extruder is maintained at least 10 degrees Celsius below a thermal decomposition initiation temperature of the chemical blowing agent.

32. The method of claim 15 , wherein the chemical blowing agent has domains each of a radius size less than 16 μm in the extruded struc

Assignees

• Toray Plastics America Inc

Inventors

• Ben-Daat Dan
• Baldwin Jesse Jude
• Bock Kaitlyn Michelle
• Sieradzki Pawel

Classifications

• B29L2007/002

  Panels; Plates; Sheets · CPC title

• B29K2105/04

  cellular or porous · CPC title

• B29K2023/12

  PP, i.e. polypropylene · CPC title

• B29C2948/92209

  Temperature · CPC title

• B29C48/872

  characterised by differential heating or cooling · CPC title