JP2003062892A - Extrusion-molding method for expansion-molding by double-screw extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foaming extrusion molding method using a completely meshing co-rotating twin-screw extruder capable of foaming molding with one extruder. SOLUTION: A resin material is supplied from a material supply port of a fully meshing co-rotating twin-screw extruder having a die attached to a tip, heated and melted, a foaming agent is injected, and a push is made from the die at the tip. In the extrusion molding method of foaming out, after filling and melting the inside of the screw groove with a resin material, a foaming agent for foaming in a region where the inside of the screw groove has a space further downstream is injected and mixed. An extrusion molding method of foam molding by the twin-screw extruder, in which the molten resin containing a foaming agent is cooled by means of a barrel or screw shaft while the molten resin containing a foaming agent is transferred in a die direction, and is extruded from the die. did.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion method using a completely meshing type co-rotating twin-screw extruder having a die attached to the tip, and in particular, a resin material is heated and melted, and then a foaming agent is injected to the die at the tip. TECHNICAL FIELD The present invention relates to an extrusion molding method for foam molding using a twin-screw extruder that extrudes from a sheet.

[0002]

2. Description of the Related Art Conventionally, an extrusion molding method of this type of foam molding will be described with reference to FIG.
After the resin material is supplied from the material supply port 2 and heated and melted, the liquid foaming agent is injected into the molten resin by the pump 3 and mixed with the molten resin material, and then the second extruder 4 of the single screw is used. Introduced into the material supply port 5, the molten resin containing the foaming agent is cooled in the second extruder 4, shaped by the die 6, foamed in the atmosphere from the die and extruded as a foamed product 7. Such a molding method.

[0003]

However, the above-mentioned conventional method requires a large equipment cost because it uses two single-screw extruders, and also requires a large installation area, resulting in energy saving,
Space saving could not be realized.

The object of the present invention is to eliminate the drawbacks that two extruders are used, the facility cost is large, and the installation area is large. One extruder can realize energy saving and space saving. An object of the present invention is to provide an extrusion molding method of foam molding by a mesh type co-rotating twin-screw extruder.

[0005]

In order to achieve the above-mentioned object, the present invention supplies a resin material through a material supply port of a completely meshing type co-rotating twin-screw extruder having a die attached to its tip, and heats it. In the extrusion molding method of foam molding in which a foaming agent is injected after being melted and extruded from the die at the tip, after the screw groove is filled and melted with a resin material, there is a void in the screw groove further downstream. Injecting and mixing the foaming agent for foaming in the area, the molten resin material containing the foaming agent is cooled by the cooling means of the barrel or screw shaft while transferring the molten resin material containing the foaming agent in the die direction. The extrusion molding method of foam molding using the twin-screw extruder is used.

Further, the injection area of the foaming agent is an area in which the screw groove is filled with the molten resin material after the resin material is melted, and the foam molding by the twin-screw extruder is performed. The extrusion molding method of Furthermore, in the injection region of the foaming agent, after the resin material is melted, the molten resin material has voids in the region where the screw groove is filled with the molten resin material and in the screw groove further downstream thereof. In the extrusion molding method of foam molding using the twin-screw extruder, The cooling means is provided with a barrel cooling hole for introducing a cooling medium into the barrel, which is an extrusion molding method for foam molding by the twin-screw extruder. The cooling means is provided with a screw cooling hole for introducing a cooling medium into the screw shaft, which is an extrusion molding method for foam molding by the twin-screw extruder.

As a result, foam molding can be performed with one completely meshing type co-rotating twin-screw extruder, and the equipment cost and the installation area can be reduced, thus saving energy and space.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to (a) and (b) of FIG. 1, and FIGS. A screw assembly 12 that completely meshes and rotates in the same direction is rotatably inserted into an inner diameter portion of a barrel assembly 11 of a completely meshing type co-rotating twin-screw extruder 10.
A material supply port 13 is provided at the base of No. 1 and a material supply device 14 for continuously supplying a constant amount of a resin material is installed. Supply to 12. Screw assembly 12
1 conveys the resin material 15 at the portion A in FIG. 1B and melts the resin material 15 at the portion B. This part B is composed of a kneading disc 16 and is used for kneading and mixing the resin material 15.
Responsible for the molten part. In the portion B, the screw groove inside the barrel 11 is completely filled with the resin material 15. The filled state is indicated by B in FIG. The portion B completely filled with the molten resin material 15a serves as a polymer seal (resin seal) with the material supply port 13 side, and the gas or the like generated in the portion C is of the polymer seal of the portion B described above. The blocking wall prevents you from going to the A side completely.

Next, the molten resin material 15a which has functioned as a polymer seal at the portion B is transferred to the portion C of FIG. In this case, the molten resin material 15a has voids in the groove of the screw 17 at the portion C. Next, it is transferred to the D portion of FIG. 1B, but in the region of the D portion, it is necessary to raise the pressure so as to overcome the flow resistance passing through the die at the tip, and the molten resin material 15a automatically moves to the screw 17 The inside of the groove will be completely filled. As a result, the C portion is in a tightly closed state in which the B portion and the D portion are completely blocked.
Then, the molten material resin 15 that has passed through the portion D is finally shaped by the die 18 and extruded, and immediately after being released into the air, foams to become a foamed product 19.

The filling state of the resin material of the screw assembly 12 is shown in the graph of FIG.

The resin material 15 supplied from the material supply port 13 into the barrel assembly 11 generates heat in the portion B as described above.
It is melted, but at that time, the foaming agent 20 may be injected into the molten resin material 15a on the surface of the kneading disk 16 in the B portion by the pump 21, and C immediately after the B portion may be injected.
It may be injected in parts. In addition, the foaming agent 20 may be injected from two locations, the B portion and the C portion. In this case, the foaming agent 20 is injected in a liquid state at the portion B, and is efficiently stirred and mixed with the molten resin material 15a on the kneading disk 16. Further, when the foaming agent 20 is injected into the C portion, since there is a void in the screw groove, even if it is in a liquid state until just before the injection of the barrel inner diameter surface, it is injected into the space after injection, and the atmosphere Because of the high temperature, the liquid of the foaming agent 20 changes into a gas body, the diffusion speed of the gaseous foaming agent 20 also increases, and the screw of the complete meshing co-rotating twin-screw extruder has one side. Screw rotates while self-wiping the surface of the other screw, and the surface of the molten resin material 15a is renewed at the meshing portions of the screws, so that the surface of the new molten resin material 15a always becomes the foaming agent 20 in the gas state. As it is exposed, the gaseous foaming agent 20 is actively impregnated into the molten resin material 15a.

On the other hand, the barrel assembly 11 is constructed by combining a plurality of barrel blocks 26, etc. of FIG. 2 according to the purpose. Further, in the portion C of FIG. 1B, it is necessary to cool the molten resin material 15a having a high temperature to the optimum temperature and adjust the viscosity of the molten resin material 15a at the outlet of the die 18 to the optimum viscosity required for foam formation. To this end, the barrel cooling holes 22 are provided in the barrel block 26, and the entire barrel block 26 is cooled by passing a cooling medium such as cooling water or cooling oil therethrough to deprive the excessive heat generation amount of the molten resin material 15a from the inner diameter surface of the barrel to melt the molten resin material. Lower the temperature of 15a and adjust to the optimum viscosity. In the screw assembly 12, as shown in FIG. 3, a cooling pipe 24 is installed in a screw cooling hole 23 of a screw shaft 25 in a cantilever state with a base of the screw shaft 25 as a fulcrum, and a cooling medium such as cooling water or cooling oil is provided. Is guided from the inner diameter portion of the pipe 24 to the screw hole diameter portion 23 as indicated by the arrow a, and the screw assembly 12 is cooled from the inside, thereby removing the excessive heat generation amount of the molten resin material 15a passing through the screw outer surface of the screw assembly 12. Then, the temperature of the molten resin material 15a is cooled and adjusted to the optimum temperature for foam molding. The barrel assembly 11 and the screw assembly 12 against the excessive heating value of the molten resin material 15a.
The above cooling devices may be used simultaneously, or one of them may be used separately.

[0013]

As described above, the extrusion method of the present invention eliminates the drawbacks of using two extruders, which requires a large equipment cost and requires a large installation area. Thus, we have been able to provide an extrusion molding method for foam molding using a complete mesh type co-rotating twin-screw extruder that can save space.

[Brief description of drawings]

FIG. 1A is an explanatory view of an extrusion molding method of foam molding by a twin-screw extruder showing one embodiment of the present invention, and FIG. 1B is a view explaining a filled state of a resin material for screw assembly. .

FIG. 2 is an explanatory diagram of an extrusion molding method of foam molding by a twin-screw extruder showing an embodiment of the present invention, and is an explanatory diagram of barrel cooling provided in a barrel block.

FIG. 3 is an explanatory diagram of an extrusion molding method of foam molding by a twin-screw extruder showing one embodiment of the present invention, and is an explanatory diagram of screw cooling provided on a screw shaft.

FIG. 4 is an explanatory diagram of one example of an extrusion molding method among conventional foam molding.

[Explanation of symbols]

10 Perfect mesh type co-rotating twin screw extruder 11 barrel assembly 12 screw assembly 13 Material supply port 14 Material supply device 15 Resin material 15a Molten resin material 16 kneading disc 17 screws 18 dies 19 Foam products 20 Foaming agent 21 pumps 22 barrel cooling holes 23 Screw cooling hole 24 Cooling pipe 25 screw shaft 26 barrel block

Claims (5)

[Claims] 1. A resin material is supplied from a material supply port of a completely meshing type co-rotating twin-screw extruder having a die attached to its tip,
In the extrusion molding method of foam molding in which a foaming agent is injected after heating and melting and extruded from the die at the tip, after the screw groove is filled and melted with a resin material, there is a void in the screw groove further downstream. Injecting and mixing the foaming agent for foaming in the existing state, and cooling the foaming agent-containing molten resin material by the cooling means of the barrel and screw shaft while transferring the foaming agent-containing molten resin material in the die direction. Extrusion molding method of foam molding by the twin-screw extruder. 2. The twin-screw extruder according to claim 1, wherein the injection area of the foaming agent is an area in which the screw groove is filled with the molten resin after the resin material is melted. Extrusion molding method for foam molding. 3. The molten resin material is melted in the injection region of the foaming agent, and then a region in which the screw groove is filled with the molten resin material and a screw groove located further downstream of the region are filled with the molten resin material. The extrusion molding method for foam molding by a twin-screw extruder according to claim 1, wherein the region is an existing region. 4. The foam molding by a twin-screw extruder according to claim 1, wherein the cooling means is provided with a barrel cooling hole for introducing a cooling medium into the barrel. Extrusion method. 5. The foaming by the twin-screw extruder according to claim 1, wherein the cooling means is provided with a screw cooling hole for introducing a cooling medium into the screw shaft. Extrusion molding method.