Vented twin-screw kneading extrusion apparatus and extrusion method

Patent metadata

Field	Value
Publication number	US-10625459-B2
Application number	US-201414902942-A
Country	US
Kind code	B2
Filing date	Aug 18, 2014
Priority date	Aug 27, 2013
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

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 (7c) provided on a downstream end segment cylinder constituted by a segment cylinder (1g) positioned on a downstream end of a cylinder assembly (1), is dispersed in molten resin in the downstream end segment cylinder (1g) and kneaded by a downstream end kneading portion (6c) 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 method for discharging organic volatile matter contained in molten resin, the molten resin being obtained by melting and kneading a synthetic resin raw material ( 11 ) that is supplied through a raw material supply port ( 3 ) on an upstream side of a cylinder ( 1 ) constituted by a multiple segment cylinders ( 1 a to 1 g ) and is formed from synthetic rubber or from two or more types of polymer including synthetic rubber, to the outside through a vent port ( 4 a , 4 b ) in the cylinder ( 1 ), and extruding the molten resin from a die ( 8 ) provided on a downstream end of the cylinder ( 1 ),
characterized in that a devolatilization agent, which is injected through a downstream end devolatilization agent injection nozzle ( 7 c ) provided on a downstream end segment cylinder constituted by a segment cylinder ( 1 g ) positioned on a downstream end of the cylinder assembly ( 1 ), is dispersed in the molten resin in the downstream end segment cylinder ( 1 g ) and kneaded by a downstream end kneading portion ( 6 c ) such that the molten resin is foamed by the devolatilization agent and then extruded.

2. The vented twin-screw kneading extrusion method according to claim 1 , characterized in that a multiple devolatilization agent injection nozzles ( 7 a , 7 b ), a multiple vent ports ( 4 a , 4 b ), and a multiple kneading portions ( 6 a , 6 b ) are provided between the raw material supply port ( 3 ) and the downstream end segment cylinder ( 1 g ) of the cylinder assembly ( 1 ).

3. The vented twin-screw kneading extrusion method according to claim 2 , characterized in that one of water, nitrogen, and carbon dioxide is used as the devolatilization agent.

4. The vented twin-screw kneading extrusion method according to claim 2 , characterized in that a cylinder temperature of the downstream end segment cylinder ( 1 g ) 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.

5. The vented twin-screw kneading extrusion method according to claim 2 , characterized in that 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 ( 8 ) equals or exceeds a vapor pressure of the devolatilization agent at the limit heat resistance temperature of the synthetic rubber.

6. The vented twin-screw kneading extrusion method according to claim 2 , characterized in that 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.

7. The vented twin-screw kneading extrusion method according to claim 2 , characterized in that the die ( 8 ) is constituted by a die having a pressure adjustment mechanism.

8. The vented twin-screw kneading extrusion method according to claim 1 , characterized in that one of water, nitrogen, and carbon dioxide is used as the devolatilization agent.

9. The vented twin-screw kneading extrusion method according to claim 8 , characterized in that a cylinder temperature of the downstream end segment cylinder ( 1 g ) 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.

10. The vented twin-screw kneading extrusion method according to claim 8 , characterized in that 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 ( 8 ) equals or exceeds a vapor pressure of the devolatilization agent at the limit heat resistance temperature of the synthetic rubber.

11. The vented twin-screw kneading extrusion method according to claim 8 , characterized in that the die ( 8 ) is constituted by a die having a pressure adjustment mechanism.

12. The vented twin-screw kneading extrusion method according to claim 1 , characterized in that a cylinder temperature of the downstream end segment cylinder ( 1 g ) 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.

13. The vented twin-screw kneading extrusion method according to claim 12 , characterized in that 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 method according to claim 12 , characterized in that the die ( 8 ) is constituted by a die having a pressure adjustment mechanism.

15. The vented twin-screw kneading extrusion method according to claim 1 , characterized in that 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 ( 8 ) 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 method according to claim 15 , characterized in that 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 method according to claim 15 , characterized in that the die ( 8 ) is constituted by a die having a pressure adjustment mechanism.

18. The vented twin-screw kneading extrusion method according to claim 1 , characterized in that 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 method according to claim 18 , characterized in that the die ( 8 ) is constituted by a die having a pressure adjustment mechanism.

20. The vented twin-screw kneading extrusion method according to claim 1 , characterized in that the die ( 8 ) is constituted by a die having a pressure adjustment mechanism.

Assignees

• Japan Steel Works Ltd

Inventors

• Shimizu Yohei
• Kakizaki Jun
• Handa Kiyoshi

Classifications

• B29K2021/00

  Use of unspecified rubbers as moulding material · CPC title

• B29B7/845 Primary

  Venting, degassing or removing evaporated components in devices with rotary stirrers · CPC title

• B29K2105/04

  cellular or porous · CPC title

• B29C48/297

  at several locations, e.g. using several hoppers or using a separate additive feeding · CPC title

• B29B7/482 Primary

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