JPH05245910A - Control method of extruder for material difficult to be kneaded and its extruding device - Google Patents

Abstract

PURPOSE:To enable miniaturization of a device, shortening of manufacturing time, etc., to be carried out by realizing simplification of a manufacturing process. CONSTITUTION:When a raw material is kneaded by a kneader 2 and a kneaded block like substance is extruded by an extruder 5, an extruded melted material has been of a sufficiently kneaded melted state. Therefore, if it is immediately discharged to a molding metal mold 7 via a gear pump 6, a high quality uniform product can be manufactured. Since double-tapered screws 5A, 5B and a single straight screw 5C of the extruder 5 are controlled according to pressure of a material extruded from the extruder 5 in that case, an inlet pressure of the gear pump 6 comes capable of being made constant. Since processes such as cooling, reservoir, etc., of the material can be omitted as a whole, a contribution can be made to miniaturization of a device, reduction of a device space, etc., accordingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is useful, for example, for producing a sheet or tube made of a difficultly kneading material by extrusion molding, and for example, a hardly kneading material (for example, a high hardness rubber material, an inorganic material). Material, highly filled synthetic resin material, ceramic material)
The present invention relates to a method for controlling an extruder for kneading and melting, and discharging the resulting mixture into a molding die for molding, and an extruder for the same.

[0002]

2. Description of the Related Art Conventionally, as an extruder for this type of material,
A kneader for kneading the difficult-to-mix material, a first extruder having an extrusion screw mechanism in which the kneaded molten material is supplied by, for example, a twin screw, and a pellet of the molten material extruded from the extruder. A pelletizer for shredding into a device, a device for cooling the shredded pellet-shaped material, a tank device for temporarily storing the cooled pellet-shaped material, and appropriately extracting the material stored in the tank device, A technique having a configuration including a second extruder that remelts this and extrudes it into a molding die is known.

Alternatively, when obtaining the pelletized material, the molten material extruded from the first extruder is supplied to a roll forming machine to form a rough sheet-like body, and the crude sheet-like body is pelletized. Techniques for doing so are also known.

[0004]

However, with any of the configurations of the above-mentioned conventional techniques, the molding material has a series of materials supply, kneading, melting, extrusion, cooling, stocking, extraction, remelting, extrusion, molding and the like. Since it requires a long process, the entire device becomes large and the installation space for the device becomes vast, and the device construction cost and device maintenance cost increase, the power consumption rises, and the time required for the entire manufacturing line becomes long. is there.

In order to simplify the manufacturing process, it is conceivable that the massive material from the kneader is simply discharged directly to the molding die by the screw of the first extruder, but with such a construction. The raw material to be fed to the first extruder is in a lump form, and the fluctuation of the supply is large. Therefore, the fluctuation of the discharge amount of the molding die is also large, and it is impossible to manufacture a uniform product.

The present invention has been made to solve the above-mentioned problems of the prior art, realizes simplification of the manufacturing process, enables downsizing of the apparatus, shortening of the manufacturing time, and the like, and a uniform product. An object of the present invention is to provide a control method and an apparatus for an extruder for a difficult-to-mix material that can be constantly molded.

[0007]

In order to achieve the above object, the invention of claim 1 is to knead a hardly kneading material into a lump material, extruding the lump material as a molten material, and the extruded molten material. Is discharged to the molding die with a substantially constant pressure.

Further, the invention of claim 2 is an extruder comprising a kneader for kneading a hardly kneading material, a lump material obtained by the kneading, and a kneading mechanism and a melt kneading mechanism, and the extruder. A gear pump for sucking the molten material extruded from the gear pump, and a molding die for molding the material discharged from the gear pump, and based on the suction pressure of the gear pump, at least the biting mechanism of the extruder and the melting And a control means for selectively controlling the extrusion mechanism.

[0009]

When the raw materials are kneaded by a kneader and the kneaded mass is extruded by an extruder, the extruded molten material is in a sufficiently kneaded and melted state, so that it is immediately molded through a gear pump. If it is discharged into a mold, a high quality uniform product can be manufactured. in this case,
Since the biting mechanism and the melt extrusion mechanism of the extruder are controlled according to the pressure of the material extruded from the extruder,
The suction pressure of the gear pump can be made constant. As a whole, steps such as cooling and storage of intermediate step materials can be omitted, which contributes to downsizing of the apparatus and reduction of the apparatus space.

[0010]

1 shows an example of an apparatus for carrying out the method according to the invention. A kneader 2 for kneading the raw material is provided on the downstream end side of the raw material charging hopper 1, and a stage 3A of a transport bucket 3 is provided below the discharge port 2a of the kneader 2.

The transfer bucket 3 is connected to a bucket transfer guide 4 extending upward, and an extruder 5 is provided at the terminal end side of the bucket transfer guide 4.
The first extruder 5 is roughly composed of twin-shaft taper screws 5A and 5B forming a biting mechanism and a single-shaft straight screw 5C forming a melt-extruding mechanism.

A gear pump 6 is provided on the extrusion port side of the extruder 5.
Further, a molding die 7 is provided, and a molten material pressure detection unit 8 is provided between the extruder 5 and the gear pump 6.

The output of the molten material pressure detection unit 8 is supplied to the taper screw drive unit 5m1 and the straight screw drive unit 5m2 of the extruder 5 via a controller 12 as a control means.

Next, the operation of the present embodiment configured as described above will be described with reference to an experimental example using a flame-retardant sheet body (for example, one having a thickness of 2 mm and a width of 500 mm) as a molding example. ..

In the hopper 1, as a raw material, for example, 100 parts by weight of a low-density polyethylene resin having a density of 0.925 and a melt index of 4, 200 parts by weight of an inorganic filler, and a compatibilizer and the like are used. 25 parts by weight of the additive was added.

When the raw materials having the above composition are supplied to the kneader 2 and sufficiently kneaded, a lump is formed, and the lump is discharged from the discharge port 2a to the bucket 3, and the bucket 3 passes through the bucket transport guide 4. Is conveyed and supplied to the extruder 5.

In the extruder 5, the agglomerate is supplied in a high biting state by the twin taper screws 5A and 5B, and is further melted by the uniaxial straight screw 5C.

The molten material has an extrusion rate of 200K.
It was extruded at a setting of g / h and a temperature of 125 ° C., and this was discharged to the mold 7 via the gear pump 6. In this case, the controller 9 was adjusted so that the suction pressure of the gear pump 6 was 75 kg / cm ² . At that time, the back pressure of the mold 10 was about 300 Kg / cm ² .

By adjusting the controller 9 and making the rotation speed of the gear pump 6 constant, the suction pressure of the gear pump 6 is 75 ± 25 Kg / cm ² , and the back pressure of the die 7 is 300 ±.
It could be maintained at 5 Kg / cm ^2, and a sheet body as a product from the mold 7 could be manufactured with a molding accuracy of 2 ± 0.05 mm in thickness.

[0020]

As described above, according to the invention of claim 1, the hardly kneading material is kneaded into a lump material, the lump material is extruded as a molten material, and the extruded molten material is pressed at a substantially constant pressure. Since it is characterized in that it is discharged to the molding die by the above, steps such as cooling, stocking, and extraction are omitted, so the overall size of the device can be reduced and the installation space for the device can be reduced. In addition, the device maintenance cost can be reduced, the power consumption can be reduced, the time required for the entire manufacturing line can be shortened, and the product cost can be reduced.

Further, the invention of claim 2 is a kneader for kneading a hardly kneadable material, an extruder having a block material obtained by the kneading and having a biting mechanism and a melt extrusion mechanism, and the extruder. A gear pump for sucking the molten material extruded from the gear pump, and a molding die for molding the material discharged from the gear pump, and based on the suction pressure of the gear pump, at least the biting mechanism of the extruder and the melting Since it comprises a control means for selectively controlling the extrusion mechanism, the invention of claim 1 can be implemented easily and concretely.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

[Explanation of symbols]

 2 kneader, 5 extruder, 5A, 5B 2 axis taper screw (biting mechanism), 5C 1 axis straight screw mechanism, 6 gear pump, 7 molding die, 9 controller (control means).

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Claims (2)

[Claims] 1. A kneading material which is difficult to knead into a lump material,
A method for controlling an extruder for a difficult-to-knead material, characterized in that the block material is extruded as a molten material and the extruded molten material is discharged into a molding die at a substantially constant pressure. 2. A kneader for kneading a hardly kneadable material, an lump material obtained by the kneading, an extruder comprising a biting mechanism and a melt extrusion mechanism, and a molten material extruded from the extruder. A gear pump for drawing in and a molding die for molding the material discharged from the gear pump are provided, and at least the biting mechanism and the melt extruding mechanism of the extruder are selectively controlled based on the suction pressure of the gear pump. An extrusion device for hardly kneading materials, which comprises: