Vented twin-screw kneading extrusion apparatus and extrusion method

Patent metadata

Field	Value
Publication number	US-11007700-B2
Application number	US-202016809933-A
Country	US
Kind code	B2
Filing date	Mar 5, 2020
Priority date	Aug 27, 2013
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

According to the present invention, devolatilization of a synthetic resin formed from a polymer or synthetic rubber can be improved and the synthetic resin can be foamed at a low temperature by injecting a devolatilization agent through a devolatilization agent injection nozzle provided in a downstream end segment cylinder of a cylinder assembly. In a vented twin-screw kneading extrusion apparatus and extrusion method according to the present invention, a devolatilization agent, which is injected through a downstream end devolatilization agent injection nozzle provided on a downstream end segment cylinder constituted by a segment cylinder positioned on a downstream end of a cylinder assembly, is dispersed in molten resin in the downstream end segment cylinder and kneaded by a downstream end kneading portion such that the molten resin is foamed by the devolatilization agent and then extruded.

First claim

The invention claimed is:

1. A vented twin-screw kneading extrusion apparatus that discharges organic volatile matter contained in molten resin, the molten resin being obtained by melting and kneading a synthetic resin raw material that is supplied through a raw material supply port on an upstream side of a cylinder constituted by a multiple segment cylinders and is formed from synthetic rubber or from two or more types of polymer including synthetic rubber, to the outside through a vent port in the cylinder, and that extrudes the molten resin from a die provided on a downstream end of the cylinder assembly,
wherein a devolatilization agent, which is injected through a downstream end devolatilization agent injection nozzle provided on a downstream end segment cylinder constituted by a segment cylinder positioned on a downstream end of the cylinder, is dispersed in the molten resin in the downstream end segment cylinder and kneaded by a downstream end kneading portion such that the molten resin is foamed by the devolatilization agent and then extruded.

2. The vented twin-screw kneading extrusion apparatus according to claim 1 , wherein a multiple devolatilization agent injection nozzles, a multiple vent ports, and a multiple kneading portions are provided between the raw material supply port and the downstream end segment cylinder of the cylinder assembly.

3. The vented twin-screw kneading extrusion apparatus according to claim 2 , wherein a cylinder temperature of the downstream end segment cylinder is set to be equal to or higher than a boiling point of the devolatilization agent and lower than a limit heat resistance temperature of the synthetic rubber.

4. The vented twin-screw kneading extrusion apparatus according to claim 2 , wherein the devolatilization agent is injected at a ratio of 1.0% to 15% relative to the molten resin, and
a back pressure on an upstream side of the die equals or exceeds a vapor pressure of the devolatilization agent at the limit heat resistance temperature of the synthetic rubber.

5. The vented twin-screw kneading extrusion apparatus according to claim 2 , wherein the synthetic resin raw material is formed from a mixture of synthetic rubber and an organic solvent, and
the devolatilization agent is formed from water.

6. The vented twin-screw kneading extrusion apparatus according to claim 2 , wherein the die is constituted by a die having a pressure adjustment mechanism.

7. The vented twin-screw kneading extrusion apparatus according to claim 1 , wherein one of water, nitrogen, and carbon dioxide is used as the devolatilization agent.

8. The vented twin-screw kneading extrusion apparatus according to claim 7 , wherein a cylinder temperature of the downstream end segment cylinder is set to be equal to or higher than a boiling point of the devolatilization agent and lower than a limit heat resistance temperature of the synthetic rubber.

9. The vented twin-screw kneading extrusion apparatus according to claim 7 , wherein the devolatilization agent is injected at a ratio of 1.0% to 15% relative to the molten resin, and
a back pressure on an upstream side of the die equals or exceeds a vapor pressure of the devolatilization agent at the limit heat resistance temperature of the synthetic rubber.

10. The vented twin-screw kneading extrusion apparatus according to claim 7 , wherein the die is constituted by a die having a pressure adjustment mechanism.

11. The vented twin-screw kneading extrusion apparatus according to claim 1 , wherein a cylinder temperature of the downstream end segment cylinder is set to be equal to or higher than a boiling point of the devolatilization agent and lower than a limit heat resistance temperature of the synthetic rubber.

12. The vented twin-screw kneading extrusion apparatus according to claim 11 , wherein the devolatilization agent is injected at a ratio of 1.0% to 15% relative to the molten resin, and
a back pressure on an upstream side of the die equals or exceeds a vapor pressure of the devolatilization agent at the limit heat resistance temperature of the synthetic rubber.

13. The vented twin-screw kneading extrusion apparatus according to claim 11 , wherein the synthetic resin raw material is formed from a mixture of synthetic rubber and an organic solvent, and
the devolatilization agent is formed from water.

14. The vented twin-screw kneading extrusion apparatus according to claim 11 , wherein the die is constituted by a die having a pressure adjustment mechanism.

15. The vented twin-screw kneading extrusion apparatus according to claim 1 , wherein the devolatilization agent is injected at a ratio of 1.0% to 15% relative to the molten resin, and
a back pressure on an upstream side of the die equals or exceeds a vapor pressure of the devolatilization agent at the limit heat resistance temperature of the synthetic rubber.

16. The vented twin-screw kneading extrusion apparatus according to claim 15 , wherein the synthetic resin raw material is formed from a mixture of synthetic rubber and an organic solvent, and
the devolatilization agent is formed from water.

17. The vented twin-screw kneading extrusion apparatus according to claim 15 , wherein the die is constituted by a die having a pressure adjustment mechanism.

18. The vented twin-screw kneading extrusion apparatus according to claim 1 , wherein the synthetic resin raw material is formed from a mixture of synthetic rubber and an organic solvent, and
the devolatilization agent is formed from water.

19. The vented twin-screw kneading extrusion apparatus according to claim 1 , wherein one of water, nitrogen, and carbon dioxide is used as the devolatilization agent.

20. The vented twin-screw kneading extrusion apparatus according to claim 18 , wherein the die is constituted by a die having a pressure adjustment mechanism.

21. The vented twin-screw kneading extrusion apparatus according to claim 1 , wherein the die is constituted by a die having a pressure adjustment mechanism.

Assignees

• Japan Steel Works Ltd

Inventors

• Shimizu Yohei
• Kakizaki Jun
• Handa Kiyoshi

Classifications

• B29C48/767 Primary

  through a degassing opening of a barrel · CPC title

• B29B7/483

  the other mixing parts being discs perpendicular to the screw axis · CPC title

• B29B7/482 Primary

  provided with screw parts in addition to other mixing parts, e.g. paddles, gears, discs · CPC title

• B29C48/022

  characterised by the choice of material · CPC title

• B29C44/3449

  through the screw · CPC title