JPH0768625A - Extrusion molding machine - Google Patents

Abstract

(57) [Summary] [Purpose] By canceling the thrust pressure applied to the screw, the production amount of molded products is increased with a small driving force. [Configuration] First and second material supply ports 11a at both ends,
A cylinder 10 provided with a discharge port 12 of the melted and mixed material in the vicinity of the central portion 11b, and a right-handed screw on one side centered on a portion positioned in the discharge port 12 and inserted in the cylinder 10. Shaped flight, a screw 30a, which forms a left-handed screw-shaped flight on the other side, and kneads and transfers the materials supplied from the first and second material supply ports 11a and 11b toward the discharge port 12, respectively. 30b is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion molding machine used for plastic processing, food processing, and the like, and particularly to increase the production amount of molded products with a small driving force by reducing the thrust pressure applied to the screw. The present invention relates to an extruder capable of molding.

[0002]

2. Description of the Related Art At present, in the field of chemical industry, a wide variety of plastic products (molded products) are actively manufactured by an extrusion molding machine in which a screw is inserted in a cylinder. As such conventional extrusion molding machines, there are a single-stage extrusion molding machine consisting of a single cylinder and a multi-stage extrusion molding machine in which two cylinders are connected to each other. There are also multi-screw type. On the other hand, as a material for the molded product, powdery or granular plastic is used, and recently, recycled materials made into a thread shape and a film shape by crushing are often used from the viewpoint of resource reuse. Of these, extrusion molding performed using a recycled material has been devised in various ways as shown in FIGS. 5 to 7 because a large thrust pressure is applied to the screw when the material is supplied to the screw in the cylinder. .

The single-stage extrusion molding machine shown in FIG. 5 has a cylinder 100 having a material supply port 101 formed at one end and a discharge port 102 for melted and mixed material provided at the other end, and this cylinder 1.
Material supplying means 103 including a hopper and a screw for supplying the material into the cylinder 00 and the discharge port 1 for discharging the material in the cylinder 100.
A screw 104 that is kneaded and transferred toward 02 and a heater 105 that heats the cylinder 100 to melt the material in the cylinder 100. According to the extruder having such a configuration, the material is forcibly supplied from the material supply port 102 into the cylinder 100 by the material supply means 103, is kneaded and transferred to the screw 104, is melted by the heat of the heater 105, and is discharged from the discharge port. It is molded and extruded from 102.

Further, Japanese Patent Publication No. 59-14051 shown in FIG.
The extruder proposed in the above publication has a structure in which a second hopper 201 is attached to the center of a cylinder 200 and the material can be supplied from this as well.

[0005] Further, as shown in FIG.
The extruder proposed in No. 1 is a first-stage extruder 300 including a first material supply unit 301 including a screw and a hopper, and a two-stage extruder including a second material supply unit 402 including a screw and a hopper. It is configured with the eye extrusion molding machine 400, and the material can be supplied from the first and second material supply means 301 and 401.

[0006]

However, in the above-described extruder shown in FIG. 5, the single material supply means 10 is used.
Since a large amount of recycled material is supplied from 3 to the cylinder 100, when the recycled material is fed into the cylinder around the material supply port 101, an excessive thrust pressure is applied to the root of the screw 104, which causes However, there is a problem that the molded product cannot be efficiently produced because the discharge capacity of the product decreases.

Further, in the extruder shown in FIG. 6, since the recycled material to be used as the material is separately supplied to the two hoppers 200 and 201, it seems that the thrust pressure is reduced. However, since the recycled material filled in these two hoppers 200 and 201 is simultaneously supplied into the cylinder by the single screw 203, the screw 203 is
As in the case of the extrusion molding machine shown in FIG. 5, an excessive thrust pressure is applied, which causes a problem that a molded product cannot be efficiently produced.

Further, in the extrusion molding machine of FIG. 7, the molten resin molded and extruded from the first-stage extrusion molding machine 300 and the recycled material supplied from the second material supply means 401 are combined in the second-stage extrusion molding machine 400. Since they are merged and extruded, an excessive thrust pressure is applied to the screw, which causes a problem that a molded product cannot be efficiently produced.

In order to solve such a problem, the inventors of the present invention have made earnest studies, and as a result, have a right-handed flight on one side and a left-handed flight on the other side with the center of the screw as a boundary. It has been found that, when the material is formed from both ends of the screw while forming the above, the thrust pressures applied to the screw cancel each other out.

As an extrusion molding machine in which the screw flight has a reverse screw shape, there is an extrusion molding machine described in Japanese Patent Publication No. 1-20975, but this extrusion molding machine is intended to cancel the thrust pressure. However, since the kneading mode of the material is special, the thrust pressure is biasedly applied to one screw shaft end, and there is a problem that the thrust pressure cannot be offset in a well-balanced manner.

The present invention has been made in view of the above problems, and provides an extrusion molding machine capable of increasing the production amount of a molded product with a small driving force by offsetting the thrust pressure applied to the screw. With the goal.

[0012]

In order to achieve the above object, the extruder of the present invention has a cylinder provided with material supply ports at both ends and a melt-kneaded material discharge port near the center. And a right-handed screw-shaped flight is formed on at least a part of one side and a left-handed screw-shaped flight is formed on at least a part of the other side centered on the portion located at the discharge port. A screw for kneading and transferring the material supplied from the material supply port toward the discharge port, preferably, the screw is a biaxial screw, and the biaxial screw is a single screw. And a single hopper having two material discharge ports. Each material discharge port of this hopper is connected to the material supply ports at both ends of the cylinder. , It is constituted to supply the same material in the cylinder.

[0013]

According to the extrusion molding machine of the present invention having the above-described structure, the materials supplied from the material supply ports at both ends of the cylinder are kneaded and transferred toward the center of the screw, so that both ends of the screw are screwed. A thrust pressure in the opposite direction is applied to each of them. That is, the thrust pressures acting on the shafts in opposite directions cancel each other out.

[0014]

Embodiments of the extruder of the present invention will be described below with reference to the drawings. First, an extruder according to the first embodiment of the present invention will be described. FIG. 1 is a side sectional view showing an extruder according to this embodiment. The extrusion molding machine of this embodiment has a structure in which separate hoppers are attached to both ends of the cylinder.

In the figure, 10 is a cylinder, and the first and second material supply ports 11 are provided at both ends thereof, respectively.
a and 11b are formed. The first and second material supply ports 11a and 11b are located at the same distance from the center of the cylinder 10 and have the same diameter.
Further, below the center of the cylinder 10, there is provided a discharge port 12 for the molten resin melted and mixed in the hollow portion of the cylinder 10. Reference numerals 21 and 22 denote first and second hoppers, which are attached to the first and second material supply ports 11a and 11b, respectively. The same first and second hoppers 21 and 22 are used, and the inside of the hoppers 21 and 22 is filled with a recycled material which is a material of the molded product.

Reference numerals 30a and 30b are biaxial screws,
It is inserted in the hollow portion of the cylinder 10. Each of the flights of these screws 30a and 30b has a right-handed screw-shaped flight on one side and a left-handed screw-shaped flight on the other side centered on the part located at the discharge port 12, and the first and second flights are formed. The materials supplied into the cylinder 10 from the material supply ports 11a and 11b are kneaded and transferred toward the discharge port 12, respectively. At this time, the screws 30a, 30
In order to apply the thrust pressure evenly to both shaft ends of b, the depths of the screw grooves on one side and the other side and the pitch of the flight are made the same. The screws 30a, 30b
The thrust pressure applied to the first and second material supply ports 11 is
Since the maximum amount is reached when the recycled material is fed into the cylinder 10 from a and 11b, it is only for the screw near the material supply port that the depth of the screw groove on one side and the other side and the pitch of the flight are the same. But it is enough.

Further, these screws 30a, 30b
Is a gear 31, 32 or a gear 3 as shown in FIG.
1, 32 and the idle gear 33 are connected so as to rotate in the same direction or different directions, and are rotated by a single drive motor 40 that transmits a driving force to the screw 30a or the screw 30b. In addition, the gears 31, 32
(And 33) may be provided on the same side as the motor 40,
In this way, the structure of the screw drive system can be simplified. The rotation direction of these screws 30a, 30b is selected from the same direction rotation (FIG. (A)) or different direction rotation (FIG. (B)) depending on the degree of biting of the material to be used. A heater 50 is attached to the peripheral surface of the cylinder 10. The heater 50 is a cylinder 1
0 is heated to melt the material in the cylinder 10.

Next, an extruder according to the second embodiment of the present invention will be described. FIG. 3 is a side sectional view showing the extruder according to this embodiment. The extrusion molding machine of the present embodiment has a configuration in which a delivery section for the molten resin is connected to the discharge port of the extrusion molding machine according to the first embodiment described above, and is particularly used when molding a resin of a material that is difficult to mix. And is effective.

In FIG. 3, reference numeral 60 denotes a carrying section for carrying the molten resin while kneading and mixing the molten resin. The carrying section 60 comprises a cylinder 61 and screws 63a and 63b inserted in the hollow part thereof. An inlet 62 for the molten resin connected to the discharge port 12 of the extruder is formed at one end of the cylinder 61, and another end of the molten resin introduced into the cylinder 61 is formed at the other end. An extrusion port is provided. A die or the like (not shown) is attached to the molten resin extrusion port.
With such a configuration, even a resin that cannot be sufficiently mixed in the apparatus of the embodiment shown in FIG. 1 can be sufficiently mixed and can be efficiently molded simply by attaching a small-sized conveying section.

Next, an extruder according to the third embodiment of the present invention will be described. FIG. 4 is a side sectional view showing the extrusion molding machine of this embodiment. The extrusion molding machine of the present embodiment is connected to a single hopper having two material discharge ports in the extrusion molding machine according to the first or second embodiment, and further, on one side and the other side of the cylinder, Each has a structure in which deaeration holes are formed.

In FIG. 4, reference numeral 70 is a hopper, and a material storage portion 71 has a first and second material discharge ports 72.
a and 72b are formed. These first and second material discharge ports 72a and 72b are connected to the first and second material supply ports 11a and 11b of the extruder, respectively. In addition, a rotatable stirring blade 80 is attached inside the material storage unit 71, and the material stored inside the material storage unit 71 is evenly distributed to the first and second material discharge ports 72a and 72b. , First and second material supply ports 11a, 11
It is supplied into the cylinder 10 via b. Furthermore, 9
Depression holes 1 and 92 are formed on one side and the other side of the cylinder 10, respectively.

In the extruder of the present embodiment having such a structure, the material is uniformly supplied into the cylinder 10 by supplying the material with the single hopper 70 having the two material discharge ports 72a and 72b. In addition, it is difficult to evenly distribute by the stirring blade 80,
For example, recycled materials having coarse particles can be easily distributed. Furthermore, by providing the deaeration holes 91 and 92,
Air, gas, moisture, etc. in the cylinder 10 are smoothly discharged to the outside. The degassing holes 91 and 92 are not limited to the present embodiment, and may be provided in the extruders of the first and second embodiments.

According to the extruders of the first to third embodiments, the recycled materials supplied from the first and second material supply ports 11a and 11b are screw 30a and screw 30a, respectively.
Since they are kneaded and transferred toward the center of b (the direction of the discharge port 12), thrust pressures in opposite directions are applied to both shaft ends of the screws 30a and 30b. That is, the thrust pressures acting on the shafts in opposite directions cancel each other out. Therefore, even if a large amount of recycled material is supplied into the cylinder 10, a large thrust pressure is not applied to the screws 30a and 30b, and the discharge capacity of the device is improved. As a result, it is possible to efficiently melt and mix the recycled material, which has been difficult to process a large amount due to the excessive thrust pressure, by the twin screw 30a, 30b driven by the single drive motor 40. .

The extruder of the present invention is not limited to the above-mentioned embodiment. For example, the present invention is preferably carried out in a twin-screw type or multi-screw type extruder having a high discharge capacity as in the above embodiment, but the present invention is applied to a single-screw type extruder. Even so, the discharge capacity can be enhanced. In addition, screw 3
The right-handed and left-handed flights formed on 0a (30b) do not necessarily have to be formed on the entire screw, but may be formed on a part of the screw depending on the usage of the extruder, the properties of the resin, etc. May be Further, in the above embodiment, the case where the regenerated material to which an excessively large thrust pressure is applied is used as the material has been described, but the molded product can be efficiently produced even when the material other than the regenerated material is used.

[0025]

As described above, according to the extruder of the present invention, it is possible to cancel the thrust pressure applied to the screw and increase the production amount of the molded product with a small driving force. .

[Brief description of drawings]

FIG. 1 is a side sectional view showing an extruder according to a first embodiment of the present invention.

[Fig. 2] Fig. 2 shows a screw of the present extruder, in which Fig. 2 (a) is a plan view when the screw is rotated in the same direction, and Fig. 2 (b) is when the screw is rotated in different directions. FIG.

FIG. 3 is a side sectional view showing an extruder according to a second embodiment of the present invention.

FIG. 4 is a side sectional view showing an extruder according to a third embodiment of the present invention.

[Figure 5],

FIG. 6,

FIG. 7 is a side sectional view showing an extrusion molding machine according to a conventional example.

[Explanation of symbols]

 10 Cylinder 11a First Material Supply Port 11b Second Material Supply Port 12 Discharge Port 21 First Hopper 22 Second Hopper 30a, 30b Screw 40 Drive Motor 50 Heater 60 Molten Resin Conveying Section 61 Cylinder 62 Molten Resin Inlet Port 63a, 63b Screw 70 Hopper 71 Material storage part 72a First material discharge port 72b Second material discharge port 80 Stirring blade 91, 92 Degassing hole

Claims (3)

[Claims] 1. A material supply port is provided at both ends,
A cylinder having a discharge port for melt-kneaded material formed in the vicinity of the center, and a right-handed screw-shaped flight, which is inserted into this cylinder and is located at one side of at least a part of the region located at the discharge port. An extruder comprising: a left-handed screw-shaped flight formed on at least a part of the side, and a screw for kneading and transferring the material supplied from the material supply port toward the discharge port. 2. The extruder according to claim 1, wherein the screw is a twin-screw screw, and the twin-screw screw is driven by a single drive motor. 3. A single hopper having two material discharge ports is provided, and each material discharge port of this hopper is connected to the material supply ports at both ends of the cylinder to supply the same material into the cylinder. The extruder according to claim 1 or 2.