JPH05245909A - Control method of extruder for material difficult to be kneaded and its apparatus - Google Patents

Abstract

PURPOSE:To enable miniaturization of an apparatus, 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 as a melted material by a first extruder 5, the melted material is supplied to a pelletizer 7 to be finely cut. Thereafter, a pellet like material is immediately supplied to a second extruder 8, remelted, and the remelted material is discharged to a molding metal mold 10 via via a gear pump 9. In that case, when the first extruder 5, the pelletizer 7, and the second extruder 8 are controlled according to pressure of the material extruded from the second extruder 8, inlet pressure of the gear pump 9 can be constant. Therefore, since processes such as cooling, reservoir, etc., of the pellet material can be omitted, a contribution can be made to miniaturization of an apparatus, reduction of an apparatus space, etc., accordingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is useful, for example, for producing a sheet or tube made of a difficult-to-knead material by extrusion molding, and a hard-to-knead material (high hardness rubber material, inorganic material,
The present invention relates to a method and apparatus for controlling an extruder for kneading and melting a highly-filled synthetic resin material, etc. and discharging the mixture into a molding die for molding.

[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.

The present invention has been made to solve the above-mentioned problems of the prior art, and for a difficult-to-knead material which realizes simplification of the manufacturing process, downsizing of the apparatus, shortening of the manufacturing time and the like. An object of the present invention is to provide an extruder control method and apparatus.

[0006]

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 shredded into pellets, the shredded pellet-shaped material is extruded as a remelted material, and the remelted material is discharged into a molding die at a substantially constant pressure.

The invention according to claim 2 further comprises a kneader for kneading the hardly kneading material, a first extruder to which the block material obtained by the kneading is supplied, and a molten material extruded from the extruder. A pelletizer for chopping into pellets, a second extruder for feeding the chopped pelletized material, and a second
A molding die for discharging the material extruded from the extruder through a gear pump, a screw mechanism of the first extruder, a shredding mechanism of the pelletizer, and the second extruder based on the suction pressure of the gear pump. And a control means for controlling at least one of the screw mechanisms.

[0008]

When the raw materials are kneaded by the kneader and the kneaded lumps are extruded as the molten material by the first extruder, the molten material is supplied to the pelletizer and shredded. Then, the pelletized material is immediately supplied to the second extruder to be re-melted, and the re-melted material is discharged to the molding die via the gear pump. In this case, the suction pressure of the gear pump can be made constant by controlling the first extruder, the pelletizer, and the second extruder according to the pressure of the material extruded from the second extruder. As a whole, steps such as cooling of pellet material and storage can be omitted, so that it can contribute to downsizing of the apparatus and reduction of the apparatus space.

[0009]

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 duct 4 extending upward, and a first extruder 5 is provided on the terminal end side of the bucket transfer duct 4. The first extruder 5 includes twin taper screws 5A and 5A.
B and a uniaxial straight screw 5C. The dies 6 and the pelletizer 7 for forming a small-diameter rod by dividing the molten resin on the extrusion direction side of the uniaxial straight screw 5C. A rotary cutter 7A, which is a breaking mechanism, is provided.

Further, a second portion is provided below the pelletizer.
An extruder 8 is provided, and an inflow port 8 of the second extruder 8 is provided.
The a is communicated with the discharge port of the pelletizer 7.

A gear pump 9 and a molding die 10 are provided on the extrusion port side of the second extruder 8.
Between the extruder 8 and the gear pump 9, a molten material pressure detection unit 1 is provided.
1 is provided.

The output of the molten material pressure detection unit 11 is output to the screw drive unit 5m of the first extruder 5, the rotary drive unit 7m of the rotary cutter 7A of the pelletizer 7, and the second drive unit through the controller 12 as the control means. Extruder 8
It is designed to be supplied to the screw drive unit 8m.

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. Are conveyed and supplied to the first extruder 5.

In the first extruder 5, the agglomerate is supplied in a highly bitten state by the twin screw taper screws 5A, 5B, and is further melted by the single screw straight screw 5C.

After passing through the screen spray 6, the molten material is cut into pellets by a pelletizer 7. Next, the pelletized material is supplied to the second extruder 8 through the inflow port 8a in a high temperature state, and the second extruder 8
Then, it becomes a molding material in a molten state again.

The remelted material was extruded from the second extruder 8 at an extrusion rate of 200 Kg / h and a temperature of 125 ° C., and was extruded into the mold 10 via the gear pump 9. In this case, the suction pressure of the gear pump 9 is 75 kg / cm.
^{2. The} controller 12 was adjusted so that the back pressure of the die 10 was 300 Kg / cm ² . At that time, the back pressure of the mold 10 was 300 Kg / cm ² .

By adjusting the controller 12 and making the rotation speed of the gear pump 9 constant, the suction pressure of the gear pump 9 is 75 ± 15 Kg / cm ² , and the back pressure of the mold 10 is 30.
It can be maintained at 0 ± 3 Kg / cm ² and the thickness of the sheet body as the product from the mold 10 is 2 ± 0.03 mm.
It was possible to manufacture with the molding precision of.

[0021]

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 made into a pellet form. Since the shredded pellet-shaped material is extruded as a remelted material and the remelted material is discharged into a molding die at a substantially constant pressure, the molding material is the first Since the steps such as cooling, stocking and extraction after being extruded by the extruder are omitted, the overall size of the device can be reduced and the installation space of the device can be reduced, and the device construction cost and the device maintenance cost can be reduced. Possible, reducing power consumption, shortening the time required for the entire production line,
As a result, the cost of the product can be reduced.

Further, the invention of claim 2 is such that a kneader for kneading the hardly kneadable material, a first extruder to which the block material obtained by the kneading is supplied, and a melt extruded from the first extruder. A pelletizer that shreds the material into pellets, a second extruder that supplies the shredded pellet material, and a molding die that discharges the material extruded from the second extruder through a gear pump. A control means for selectively controlling at least the extrusion screw mechanism of the first extruder, the shredding mechanism of the pelletizer, and the extrusion screw mechanism of the second extruder based on the suction pressure of the gear pump. Therefore, 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 1st extruder, 7 pelletizer, 8 2nd extruder, 9 gear pump, 10 molding die, 12 controller (control means).

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Claims (2)

[Claims] 1. A kneading material which is difficult to knead into a lump material,
The massive material is extruded as a molten material, the extruded molten material is shredded into pellets, the shredded pelletized material is extruded as a remelted material, and the remelted material is molded at a substantially constant pressure. A method for controlling an extruder for difficultly kneading materials, characterized in that the extruder is used for discharging. 2. A kneader for kneading a hardly kneadable material, a first extruder to which a block material obtained by the kneading is supplied, and a molten material extruded from the first extruder, which is shredded into pellets. Pelletizer, a second extruder that supplies the shredded pellet-shaped material, a molding die that discharges the material extruded from the second extruder through a gear pump, and a suction pressure of the gear pump. Based on at least the extrusion screw mechanism of the first extruder, the shredding mechanism of the pelletizer, and the control means for selectively controlling the extrusion screw mechanism of the second extruder. Material extrusion equipment.