JP2000190378A - Extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously extrude a mixed material of natural fibers and a thermoplastic fibers in a screw extruder. SOLUTION: An extrusion head 18 is provided to the leading end part of a first cylinder 11 and the leading end of a second cylinder 12 is integrally connected to the first cylinder 11 at a position separated from the leading end part thereof. Heaters 14a, 14b are provided to the first and second cylinders 11, 12 and a hopper is provided at a position separated from the leading end of the second cylinder 12. The extrusion screw 15 coaxially provided in the first cylinder 11 is rotationally driven by a screw driving device 16. The plunger 17 fitted in the second cylinder 12 in a freely slidable manner and reciprocally moved by a plunger driver 20 pushes the mixed material, which is supplied from the hopper and of which the thermoplastic fibers are melted in a push-in cylinder, into the first cylinder 11. The angle α formed by the center line 01 going toward the leading end part of the first cylinder 11 and the center line 02 of the second cylinder is pref. set to an obtuse angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruder for extruding a material obtained by mixing a natural fiber and a thermoplastic fiber and supplying the material to a mold.

[0002]

2. Description of the Related Art As a technique for molding a mixture of natural fibers and thermoplastic fibers (polyester fibers) as a material, there is a method shown in FIG. For this, first, a natural fiber and a thermoplastic fiber supplied from a hopper onto a conveyor at a predetermined ratio are sent to the cross layer 1 as a single-layer mat 8A in which a natural fiber and a thermoplastic fiber are uniformly mixed by a card machine. Cross layer 1
Moves the single-layer mat 8A onto the conveyor 3 which moves in the Z direction orthogonal to the Y direction while reciprocating the layer conveyor 2 at the tip end thereof as shown by the arrow Y, thereby causing the A strip-shaped multi-layered mat 8B which is slightly shifted and overlapped is formed. The multi-layered mat 8B conveyed by the conveyer 3 is cut and removed by a pair of side cutters 5 in which the unnecessary portions 8Ba on both sides are rotating, and is conveyed onto a take-out conveyer 34, where it is orthogonal to the Z direction. It is cut by the separation cutter 6 moving in the direction and is placed on the lower die 7a of the hot press device 7. Then, it is compressed by the descending upper die 7b as shown in the intermediate product 8C of FIG. 4, and unnecessary portions around it are cut off by fixed size cutting to obtain a finished product 8D of a predetermined size.

[0003]

As described above, in the method of cutting the strip-shaped multi-layered mat 8B and compressing it with the hot press device 7, it is not possible to produce a continuous long product or a complicated molded product. Can not. As a means to solve such a problem, it is conceivable to use a screw-type extruder.However, since a material obtained by mixing natural fibers and thermoplastic fibers is intertwined with each other, the vicinity of the feed port of the extruder At the same time, it is entangled with the blade of the extrusion screw and is not fed in the axial direction. For this reason, the mixed material of the natural fiber and the thermoplastic fiber cannot be formed by an extrusion molding method using a screw type extruder or an injection molding method.

[0004] The present invention solves such a problem and makes it possible to continuously extrude a mixed material of natural fibers and thermoplastic fibers by a screw type extruder, thereby enabling extrusion and injection molding. The purpose is to:

[0005]

According to the present invention, there is provided an extruding apparatus comprising: a first cylinder having a cylindrical extruding head provided at an extremity; and an extremity integrally connected to a position apart from the extremity of the first cylinder. A second cylinder, a hopper provided at a position distant from the tip of the second cylinder, a first heater and a second heater for heating the first cylinder and the second cylinder, and An extrusion screw provided coaxially and rotationally driven by a screw driving device; a natural fiber supplied from the hopper by being slidably fitted in the second cylinder and reciprocated by a plunger driving device; The mixed material of fibers is
A plunger that is pushed into the cylinder is provided. Since the mixed material of the natural fiber and the thermoplastic fiber supplied from the hopper is heated by the second heater in the second cylinder, the mixed material is made of the thermoplastic fiber.
After being melted in the cylinder, it is pushed into the first cylinder by the plunger.

In the above invention, it is preferable that an angle formed by a center line extending from a connecting position of the first cylinder and the second cylinder toward a tip end of the first cylinder and a center line of the second cylinder is an obtuse angle. With this configuration, the direction in which the molten mixed material is pushed into the first cylinder from the second cylinder approaches the direction in which the molten screw is pushed out by the extrusion screw.

It is preferable that the plunger driving device according to the above-mentioned inventions is a hydraulic cylinder device.

[0008] It is preferable that the screw drive device according to the above-mentioned inventions is a motor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An extruder according to the present invention will be described below with reference to an embodiment shown in FIGS. FIG.
And the casing of the extruder 10 as shown in FIG.
The first cylinder 11 and the second cylinder 12 are integrally fixed to each other. An extrusion head 18 is coaxially mounted on the distal end of the cylindrical first cylinder 11, an extrusion die 19 is mounted on the distal end thereof, and the rear end of the first cylinder 11 is substantially closed. . The front end of the second cylinder 12 is integrally fixedly connected to the rear end of the first cylinder 11 near the rear end thereof. The interiors of the two cylinders 11 and 12 are communicated with each other, and a center line O1 extending from a position where the two are joined to a tip end of the first cylinder 11 and a center line O of the second cylinder 12 are connected.
2 is an obtuse angle. An opening 12a provided at a position distant from the tip of the second cylinder 12 has a hopper 1 for charging a mixed material 30 of natural fibers and thermoplastic fibers.
3 are provided. Around the first cylinder 11 and the second cylinder 12, first and second heaters 14a and 14b for heating them are provided.

The mixed material 30 supplied from the hopper 13
Is a fiber obtained by supplying a sufficiently defibrated natural fiber and a thermoplastic fiber at a predetermined ratio and uniformly mixing the resulting mixture with a card machine. The natural fiber is, for example, a fiber such as wood fiber, bamboo, palm, straw, or kenaf, and the thermoplastic fiber is, for example, a polyester fiber (thickness is 2 to 100 denier) such as polypropylene, polyethylene, or polyethylene terephthalate. And the mixing ratio of thermoplastic fiber is 30: 70-
70:30.

As shown in FIGS. 1 and 2, an extrusion screw 15 having a helical blade 15a formed on the outer periphery is coaxially rotatably supported in the first cylinder 11. The extrusion screw 15 is rotationally driven by a screw driving device 16 provided at a rear portion of the first cylinder 11 in a direction in which the mixed material with the first cylinder 11 is extruded toward an extrusion head 18 by a blade 15a. Screw drive 16 of this embodiment
Is a motor 16 provided coaxially with the extrusion screw 15.

A plunger 17 is slidably fitted in the second cylinder 12, and is moved by a plunger driving device 20 between a retracted position shown by a solid line in FIG. 1 and an advanced position shown by a solid line in FIG. Reciprocated. The plunger driving device 20 of this embodiment includes a cylinder 21, a piston 22 slidably fitted on the inner surface thereof, and a piston 22 at both ends.
And a rod 23 connected to the plunger 17.

Next, the operation of the above embodiment will be described.
Most of the extruder 10 excluding the fluid pressure cylinder device 20 is heated to, for example, 200 ° C. by the heaters 14 a and 14 b before the operation starts. While the extrusion screw 15 is rotationally driven by the motor 16, the pressurized working fluid is alternately supplied to the two ports 21 a and 21 b of the fluid pressure cylinder device 20 to reciprocate the plunger 17. As a result, the mixed material 30 of the natural fiber and the thermoplastic fiber supplied from the hopper 13 is pushed into the first cylinder 11 through the second cylinder 12.
Numeral 0 indicates that the thermoplastic fiber is melted when passing through the second cylinder 12, and when the thermoplastic fiber is pushed into the first cylinder 11, the molten fiber 31 is mixed with natural fibers.

Since the molten thermoplastic fiber performs a lubricating action on the molten mixed material 31, the natural fiber does not become entangled with the blade 15a of the extrusion screw 15, and is sent in the axial direction according to the rotation of the extrusion screw 15. After passing through the extrusion head 18 and as shown in FIGS.
9 are continuously extruded from the extrusion port 19a to form a continuous extruded product 32. The extruded product 32 is cut to a desired length and taken out.

According to such an embodiment, extrusion molding or injection molding by a screw type extruder can be performed using a mixed material of natural fibers and thermoplastic fibers.

In the above embodiment, the first cylinder 1
From the position where the first and second cylinders 12 are joined, the first cylinder 11
Is formed at an obtuse angle between the center line O1 toward the front end of the first cylinder 11 and the center line O2 of the second cylinder 12, whereby the molten mixed material 3 from the second cylinder 12 with respect to the first cylinder 11
Since the pushing direction of 1 is closer to the direction of extrusion by the extrusion screw 15, the molten mixed material 31 can easily enter the first cylinder 11, and the extrusion of the extruded product 32 from the extrusion head 18 is stable and reliable. .

In the above embodiment, since the plunger driving device is the fluid pressure cylinder device 20 and the screw driving device is the motor 16, the structure of the pushing device is simplified.

In the above-described embodiment, an example in which the extrusion die 19 is provided at the tip of the extrusion head 18 to form the extruded product 32 has been described. And the molten mixed material extruded from the extrusion head 18 can be injected into an injection molded article to perform molding.

[0019]

According to the present invention, the mixed material of the natural fiber and the thermoplastic fiber is pushed into the first cylinder by the plunger after the thermoplastic fiber is melted in the second cylinder. In the mixed material of these two fibers, the melted thermoplastic fiber performs a lubricating action, so that the natural fiber does not become entangled with the blade of the extrusion screw, and is sent in the axial direction according to the rotation of the extrusion screw and continuously from the extrusion head. Pushed out. Therefore, according to the present invention, extrusion molding or injection molding can be performed using a mixed material of natural fibers and thermoplastic fibers.

According to the present invention, the angle between the center line from the connecting position of the first cylinder and the second cylinder toward the tip of the first cylinder and the center line of the second cylinder is made obtuse. Since the direction of pushing the molten mixed material from the second cylinder approaches the direction of extrusion by the extrusion screw, the molten mixed material can easily enter the first cylinder, and the extrusion of the molten mixed material from the extrusion head is stable and reliable. become.

According to the present invention, in which the plunger driving device is a hydraulic cylinder device, the structure of the plunger driving device is simplified. Further, according to the present invention in which the screw driving device is a motor, the structure of the screw driving device is simplified.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the overall structure of an embodiment of an extrusion device according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a perspective view showing a state in which the extruded product of the embodiment shown in FIG. 1 is being formed.

FIG. 4 is an overall perspective view of a main part showing an example of a conventional technique of molding a material obtained by mixing a natural fiber and a thermoplastic fiber as a material.

[Explanation of symbols]

11 ... first cylinder, 12 ... second cylinder, 13 ... hopper, 14a ... first heater, 14b ... second heater, 15 ...
Extrusion screw, 16: Screw drive (motor), 17: Plunger, 18: Extrusion head, 20:
Plunger drive (fluid pressure cylinder device), O1, O
2 ... Center line, α ... Angle.

Claims (4)

[Claims] 1. A first cylinder having a cylindrical shape provided with an extruding head at a distal end, a second cylinder having a distal end integrally connected to a position apart from the distal end of the first cylinder, and a second cylinder A hopper provided at a position distant from the tip of the first cylinder, and a first hopper for heating the first cylinder and the second cylinder.
A heater and a second heater, an extrusion screw provided coaxially in the first cylinder and rotationally driven by a screw driving device, and reciprocally moved by the plunger driving device slidably fitted in the second cylinder. An extruder comprising a plunger for pushing a mixed material of natural fibers and thermoplastic fibers supplied from the hopper into the first cylinder. 2. The extrusion according to claim 1, wherein the angle formed by the center line of the first cylinder and the center line of the second cylinder from the connecting position of the first cylinder and the second cylinder to the tip of the first cylinder is an obtuse angle. apparatus. 3. The extrusion device according to claim 1, wherein the plunger driving device is a hydraulic cylinder device. 4. The extrusion device according to claim 1, wherein the screw driving device is a motor.