APPARATUS AND METHOD FOR PLASTIC EXTRUSION

• US 20120081989A1
• Filed: 09/14/2011
• Published: 04/05/2012
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: Japan Steel Works Limited
• Original Assignee: Japan Steel Works Limited
• Inventors: YATA, Kyohei, TAKAMOTO, Seiji, KOBAYASHI, Fumio, INOUE, Shigeki
• Granted Patent: US 8,870,441 B2
• Time in Patent Office: Days
• US Class Current: 366/75
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/395 using screws surrounded by a cooperating barrel, e.g. single screw extruders
• CPC Class Codes: B29C 48/404 the screws having non-intermeshing parts
• CPC Class Codes: B29C 48/41 Intermeshing counter-rotating screws
• CPC Class Codes: B29C 48/57 provided with kneading disc-like elements, e.g. with oval-shaped elements
• CPC Class Codes: B29C 48/6801 characterised by the material or their manufacturing process
• CPC Class Codes: B29C 48/682 for twin screws
• CPC Class Codes: B29C 48/686 having grooves or cavities
• CPC Class Codes: B29C 48/76 Venting , drying means; Degassing means

Abstract

An object of the invention is to improve capacity of process and not require a vent portion by an upper polygonal groove and a transition portion provided to a transport cylinder.

A plastic extrusion method and apparatus according to the invention is a method and a configuration, in which an upper polygonal groove and a transition portion are integrally or separately provided to a transport cylinder so as to increase a frictional coefficient of an inner wall of the cylinder, to increase transport efficiency of a plastic raw material by a screw, and to allow at least gas, etc., pass toward a hopper side without using a vent portion.

Claims

1. A plastic extrusion method comprising:

preparing a cylinder comprising a transport section cylinder, a kneading section cylinder and a releasing section cylinder, wherein a screw is installed in the cylinder and comprises a transport section screw, a kneading section screw and a releasing section screw;

supplying a plastic raw material into the cylinder from a hopper of a raw material supplying portion at an upstream side of a transport section cylinder;

plasticizing and kneading the plastic raw material; and

extruding the plasticized and kneaded material from the releasing section cylinder,

wherein the transport section cylinder comprises an upper polygonal groove and a transition portion, the transition portion being arranged at the downstream side of the upper polygonal groove and being configured as a shape in which the upper polygonal groove gradually disappears, and

wherein in the supplying the plastic raw material, the plastic extrusion method comprises releasing at least inert gas components and volatile components toward the hopper when the plastic raw material passes through the upper polygonal groove.

2. The plastic extrusion method according to claim 1,

wherein the cylinder comprises no vent portion for releasing the inert gas components and volatile components to an outside.

3. The plastic extrusion method according to claim 1,

wherein the upper polygonal groove comprises at least four grooves, and

wherein a depth H of the at least four grooves satisfies 0<

H≦

0.1 D, where D is the inner diameter of the cylinder.

4. The plastic extrusion method according to claim 1,

wherein the screw is configured as twin screws.

5. The plastic extrusion method according to claim 1,

wherein the screw is configured as twin screws turning inwards in different directions.

6. The plastic extrusion method according to claim 1,

wherein the upper polygonal groove is provided in a separate upper polygonal cylinder.

7. The plastic extrusion method according to claim 1,

wherein the upper polygonal groove and the transition portion are provided in a separate transition cylinder.

8. The plastic extrusion method according to claim 1,

wherein the upper polygonal groove and the transition portion are integrally incorporated in the cylinder.

9. A plastic extrusion apparatus for supplying a plastic raw material into a cylinder from a hopper of a raw material supplying portion at an upstream side of a transport section cylinder, for plasticizing and kneading the plastic raw material and for extruding the plasticized and kneaded material from a releasing section cylinder,

wherein the cylinder comprises the transport section cylinder, a kneading section cylinder and the releasing section cylinder,

wherein a screw is installed in the cylinder and comprises a transport section screw, a kneading section screw and a releasing section screw is installed in the cylinder,

wherein the transport section cylinder comprises an upper polygonal groove and a transition portion, the transition portion being arranged at a downstream side of the upper polygonal groove and being configured as a shape in which the upper polygonal groove gradually disappears, and

wherein the plastic extrusion apparatus is configured to release at least inert gas components and volatile components toward the hopper when the plastic raw material passes through the upper polygonal groove.

10. The plastic extrusion apparatus according to claim 9,

wherein the cylinder comprises no vent portion for releasing the inert gas components and volatile components to an outside.

11. The plastic extrusion apparatus according to claim 9,

wherein the upper polygonal groove comprises at least four grooves, and

wherein a depth H of the grooves satisfies 0<

H≦

0.1 D, where D is the inner diameter of the cylinder.

12. The plastic extrusion apparatus according to claim 9,

wherein the screw is configured as twin screws.

13. The plastic extrusion apparatus according to claim 9,

wherein the screw is configured as twin screws turning inwards in different directions.

14. The plastic extrusion apparatus according to claim 9,

wherein the upper polygonal groove is provided in a separate upper polygonal cylinder.

15. The plastic extrusion apparatus according to claim 9,

wherein the upper polygonal groove and the transition portion are provided in a separate transition cylinder.

16. The plastic extrusion apparatus according to claim 9,

wherein the upper polygonal groove and the transition portion are integrally incorporated in the cylinder.