JP2001287223A - Method for forming pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming pellets wherein an extruded continuous extrudate can be surely cut by means of a rotating blade and adhesion caused by static electricity, etc., can be prevented from being generated and in addition, it contributes to miniaturization of an installation. SOLUTION: In the method for forming the pellets which are formed by cutting the above described continuous extrudate S by means of the rotating blade 2a after the continuous extrudate S of a thermoplastic resin extruded from an extruder is cooled in advance by a cooling means, when the above described continuous extrudate S is cut by means of the rotating blade 2a, temperature of this rotating blade is lowered by blowing air flow on the rotating blade 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming pellets, and more particularly, to a method for forming pellets suitable for forming soft resin pellets.

[0002]

2. Description of the Related Art Soft resins obtained by mixing rubber, polybutene, tackifier and the like with a thermoplastic resin such as polyolefin are widely used for automobile parts, seal materials, industrial parts and the like. Such a resin is usually extruded by an extruder, cooled in a water tank, drained, and then cut into a number of pellets by a rotary blade of a pelletizer.

[0003]

However, when a continuous extruded body made of a soft resin is cut into pellets by a rotary blade in this way, if the soft resin is not sufficiently cooled, a part of the resin is removed by the rotary blade. And the cutting by the rotary blade becomes gradually dull. In addition, when the pelletizing operation is continuously performed, the rotary blade generates heat, and the heat causes the pellets to dance between the blades, so that the pellets are re-adhered to each other. In addition, when the continuous operation is performed, the pellets are charged by static electricity generated by the rotary blade, and as a result, there is a problem that the pellets are in close contact with each other and are not swept out to the discharge port. In addition, in such a method, it is necessary to prepare a water tank having a sufficient length to cool the extruded continuous extruded body by the cooling means. As a result, there is a problem that the equipment becomes large.

The present invention has been made in view of such circumstances, and it is possible to reliably cut an extruded continuous extruded body with a rotary blade, to prevent the extruded continuous extruded body from sticking due to static electricity or the like. It is an object of the present invention to provide a method for forming pellets that contributes to downsizing of equipment.

[0005]

According to the present invention, there is provided a method for forming a pellet, comprising: cooling a continuous extruded thermoplastic resin extruded from an extruder by a cooling means in advance; In a pellet forming method for cutting a continuous extruded body with a rotary blade to form a pellet, air is blown to the rotary blade when the continuous extruded body is cut by the rotary blade.

According to such a method, the rotary blade at the time of cutting is cooled, so that the cutting ability of the rotary blade can be maintained for a long period of time. Further, in the present invention, it is preferable that the air is directly blown to a rotary blade involved in cutting the continuous extruded body.

In this way, even if the pellets adhere to the rotary blade and are hard to separate, the pellets can be forcibly separated from the rotary blade. Here, it is preferable that the rotary blade is covered with a hood, and the hood prevents the air from being blown out.

[0008] With such a configuration, the energetic air does not blow out to the surroundings, and the air flow can be used efficiently without waste. Further, the cooling means is preferably a cooling tank in which cooling water is stored.

With such a cooling means, the length of the cooling tank can be shortened, which contributes to downsizing of the equipment. Here, it is preferable that the continuous extruded body is preliminarily cooled by the air cooling unit before the continuous extruded body is conveyed from the cooling unit to the rotary blade.

In this case, the cooling effect can be further improved, and the use of the dead space can contribute to downsizing of the apparatus.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming a pellet according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view of an entire apparatus in which a pellet forming method according to the present invention is performed, and FIG. 2 is a schematic top view thereof. On an upper surface of the pellet forming apparatus body 1, a roller 2 on which a number of rotary blades 2a are formed is provided. The roller 2 is usually provided with a hood 10 as shown in FIG.
Covered by The hood 10 is detachably attached to an apparatus frame or the like so as not to interfere with the maintenance and inspection of the roller 2 described above. In addition, food 10
Is formed with an opening 11 for introducing air, and one end of a hose 12 for supplying cooling air to the opening 11 is attached to the opening 11. The opening for introducing air into the hood 10 may be vertically, horizontally, or downwardly. Further, two or more openings may be provided at the same time. Here, it is preferable that the air sent into the hood 10 directly cools the rotating blade 2a at the cutting position among the plurality of rotating blades 2a,
In this case, a discharge port having a short pipe may be provided in the hood 10. In this way, the air introduced into the hood 10 from the hose 12 can cool the rotary blade 2a at a predetermined position via the discharge port.
Further, the blown air hits another member and rebounds, so that the other rotary blades 2a can be cooled.

On the other hand, in the vicinity of the roller 2 provided with the rotary blade 2a, a guide roller 3 which is partially exposed from the base 4 is accommodated. Guide rollers 5, 6, 7 are attached to the support bracket 8 on the sides of the base 4.

Below such a support bracket 8,
An air nozzle 9 is provided as air cooling means, and cooling air from a compressor (not shown) is jetted upward from below through the air nozzle 9. In addition, as shown in FIG.
The outlets 9a are provided over substantially the entire width of the nozzles 6 and 7.

In the present invention, as the resin forming the pellet, a thermoplastic resin, for example, a soft resin obtained by mixing rubber, polybutene, a tackifier and the like with a polyolefin resin is used.

[0016] Such a soft resin is first melt-kneaded by an extruder (not shown), and is extruded from its outlet. Since the extruded continuous extruded body S cannot be cut as it is at a high temperature, for example, the extruded continuous extruded body S is once housed in a water tank filled with cooling water, and is conveyed in the water tank to some extent. Is cooled to the temperature of The cooled continuous extruded body S is taken out of the water tank, drained, and then delivered to the pellet forming apparatus 1 shown in FIG. Usually, as shown in FIG.
Since the continuous extruded body S is extruded simultaneously in a plurality of rows,
It is delivered to the pellet forming device 1 side by side in the width direction.

The plurality of continuous extruded bodies S sent to the pellet forming apparatus 1 are sent to the downstream roller 3 via the rollers 5, 6, and 7, and then reach the rotation area of the rotary blade 2a. To small pieces sequentially.

Here, even if the continuous extruded body S has not yet been sufficiently cooled, in this embodiment, an air nozzle 9 for jetting air is provided below the bracket 8 as another cooling means. Therefore, the continuous extruded body S can be further cooled by the air from the air nozzle 9. Therefore, the continuous extruded body S taken out of the water tank
Can be cooled thereafter.

On the other hand, air is taken into the hood 10 and the air blows vigorously directly at the cut portion between the rotary blade 2a and the continuous extruded body S, so that the pellets P cut from the continuous extruded body S rotate. It does not adhere to the blade 2a or the like. Further, the cut pellets P can be quickly dropped downward. Moreover, in the present invention, even when the rotary blade 2a is continuously operated, it is possible to prevent the heat generation of the rotary blade 2a by the air flow. Thereby, generation of static electricity can be prevented.

As described above, the pellets sequentially cut by the rotary blade 2a are transferred from the hood 10 to the passage 2 in the apparatus 1.
3 through the outlet 24. Therefore, if a bag 25 or the like is set below the outlet 24,
Cut pellets P into bags 25 without being affected by static electricity.
Can be loaded quickly.

The embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example,
In the above embodiment, a cooling bath using cooling water is exemplified as a cooling unit for the continuous extruded body S extruded by the extruder, but this cooling unit may be another unit.

The air nozzle 9 disposed below the rollers 5, 6, 7 and the like is not essential. When the continuous extruded body cooled in the cooling tank is sufficiently cooled, the air nozzle 9 may be omitted. Further, in the above embodiment, only air is blown from the air nozzle 9 or 11, but the air may contain a powder of a lubricant. In this way, the surface of the pellet P can be substantially uniformly covered with the lubricant powder.

[0023]

As described above, according to the present invention,
When cutting a continuous extruded body made of a thermoplastic resin or the like, it is possible to prevent these resins from being caught on the rotary blade or generating heat from the rotary blade. Further, the adhered resin does not adhere again due to heat. Also,
Adhesion due to static electricity can also be prevented. In addition, the length of the cooling tank before cutting can be shortened. Therefore,
This can contribute to downsizing of the device.

[Brief description of the drawings]

FIG. 1 is a plan view of an apparatus in which the present invention is implemented.

FIG. 2 is a schematic top view of FIG. 1;

FIG. 3 is a perspective view of a hood provided in the apparatus of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Device 2 ... Roll 2a ... Rotary blade 11 ... Opening 12 ... Hose P ... Pellets S ... Continuous extruded body

Claims (5)

[Claims] 1. A method for forming pellets, comprising cooling a continuous extruded body of a thermoplastic resin extruded from an extruder by a cooling means in advance, and cutting the continuous extruded body with a rotary blade to form pellets. A method for forming pellets, wherein air is blown onto the rotary blade when the continuous extruded body is cut by the rotary blade. 2. The method according to claim 1, wherein the air is directly blown to a rotary blade involved in cutting the continuous extruded body.
The method for forming a pellet according to the above. 3. The pellet forming method according to claim 1, wherein the rotary blade is covered with a hood, and the hood prevents diffusion of the air. 4. The pellet forming method according to claim 1, wherein said cooling means is a cooling tank in which cooling water is stored. 5. The continuous extruded body is preliminarily cooled by air cooling means before the continuous extruded body is conveyed from the cooling means to the rotary blade. Pellet forming method.