JP2009279773A - Method of manufacturing synthetic resin pellet with little fine powder and device for removing fine powder from synthetic resin pellet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high-quality pellets with little fine powder by removing fine powder such as chips and crushed pieces attached to synthetic resin pellets, and to provide a device for removing the fine powder from the synthetic resin pellets. <P>SOLUTION: The method of removing fine powder on the synthetic resin pellets comprises steps of: moving the synthetic resin pellets stored in a tank so as to draw out the synthetic resin pellets from the neighborhood of a lower part of the tank by means of pneumatic conveyance through a pellet circulation piping and return the synthetic resin pellets from the neighborhood of an upper part of the tank; removing static electricity by causing ions from an ion generator to contact with the synthetic resin pellets during movement to release the fine powder statically attached to the synthetic pellets and turn the fine powder into a suspended state; and discharging the fine powder in the suspended state from the opening disposed on the neighborhood of the upper side of the tank to the outside of the tank while entraining the fine powder into air. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention removes adhering fine powders such as chips and crushed pieces from synthetic resin pellets, so that synthetic resin pellets with less fine powder (hereinafter, “synthetic resin pellets” may be simply referred to as “pellets”). It relates to a method of manufacturing. More specifically, the present invention relates to a method for removing fine particles that are electrostatically attached to the pellets by removing them from the pellets.

Generally, a thermoplastic resin is kneaded under heating together with various additives that are blended as desired, then extruded into strands, cooled, solidified and cut into pellets having a length of several millimeters. Commercialized and shipped. By the way, fine pellets are generated during pelletization, and fine particles are generated and adhered to the pellet surface when the pellets are crushed or the like during conveyance or other handling of the pellets.
These fine powders adhering to the pellets obstruct stable transportation and metering when the pellets are pneumatically transported to material supply tanks such as extruders and injection molding machines, and when metering during molding. May be adversely affected. Therefore, various methods and apparatuses for removing fine powder adhering to the pellet have been proposed.

  For example, a cone is placed in the center of a cylindrical casing, and while dropping the pellet along the conical surface of the cone, rising air is sent between the casing and the cone to separate fine powder from the pellet. , A method of removing (Patent Document 1), a method of removing fine foreign matter (differentiation) mixed between pellet surfaces or pellets by blowing high-speed high-pressure clean air while dropping the pellets continuously (Patent Document 1) Documents 2) and the like have proposed methods and apparatuses for physically separating and removing fine powder.

In addition, synthetic resin is inherently easily charged with static electricity, and fine powder adheres to the pellets due to static electricity and is difficult to remove by physical means alone. Various proposals have also been made.
For example, a static eliminator that neutralizes the static electricity charged in the pellets, and inclined separation plates and induction plates that are alternately arranged in multiple stages and with a drop interval at each stage, the pellets are zigzag An apparatus for removing fine particles of pellets using a separation tower that drops while being guided into a shape has been proposed (Patent Document 3). In this patent document, the air sucked into the tower from the inlet provided on one side of the separation tower is raised along the slope of each inclined separation plate, and the charge is neutralized (removed) by the static eliminator. It is described that the fine powder is separated and floated from the pellet, and the separated fine powder is sucked out of the tower through the vent opening opened to the other side of the separation tower, and the pellet from which the fine powder has been removed is obtained from the lower outlet of the separation tower. ing. Also, in the same apparatus as in Patent Document 3, take out the vessel composed of the inclined separation plate and the guide plate from the side opening and move it to another place convenient for work to clean the vessel. An apparatus capable of performing the above has also been proposed (Patent Document 4).

In addition, ionized air is blown onto the raw material pellets supplied to the molding machine, and the inside of the casing is lowered while swirling the raw material pellets, and fine powder separated from the raw material pellets is caged through a mesh filter provided in the casing. Fine powder remover that can be removed from the inside (Patent Document 5), static electricity remover that neutralizes (removes) the static electricity of the pellet, fine powder separator that separates the pellet and fine powder, and stores the separated fine powder Have a fine powder storage device and a pellet storage device for storing pellets from which fine powder has been removed, and the static electricity is removed by ionized air coming out of the static electricity removal device while dropping the pellets, and separated. A device for separating fine powder and pellets by blowing off fine powder (Patent Document 6) has also been proposed. .

JP 2007-30359 A JP-A-8-196997 JP-A-10-620 JP 2002-282791 A JP 2007-50354 A JP-A-8-39550

  As described above, the synthetic resin itself has a property of being easily charged. According to the study by the present inventors, the charge amount of the pellet varies depending on the kind of the synthetic resin and the additive added. If it is resin, it is usually 8 to 15 kv. Since the fine powder adheres to the pellets having such a high charge amount due to static electricity, the attached fine powder is difficult to remove easily, and even when separated by the above-described separation apparatus, It was found that a considerable amount of fine powder was still attached. Even in the pellet from which the fine powder has been removed, the fine powder may adhere again due to friction and impact during subsequent handling. When producing pellets, pellets with protrusions such as mustaches or burrs may be generated. These parts are crushed during handling to generate fine powder, or the surface peels off due to friction between the pellets. By generating fine powder.

  An object of this invention is to provide the high quality pellet with few fine powders in view of an above described situation.

  As a result of intensive studies in order to solve the above problems, the present inventors have moved the pellets stored in the tank by air flow through the pellet circulation pipe, and by removing the charge of the pellets in this process By removing fine particles that are attached to the pellets from the synthetic resin pellets, the fine particles floating in the tank are discharged from the tank through the exhaust port provided near the top of the tank and discharged from the tank. The inventors have found that high quality pellets can be obtained and completed the present invention.

  That is, the gist of the present invention is that the synthetic resin pellets accommodated in the tank are extracted from the vicinity of the lower part of the tank and returned to the tank in the vicinity of the upper part of the tank by the air flow through the pellet circulation pipe. Ions generated by the ion generator are brought into contact with the synthetic resin pellets, and the fine particles that are electrostatically attached to the synthetic resin pellets are separated from the synthetic resin pellets, and then separated from the synthetic resin pellets and suspended in the tank. In a synthetic resin pellet with a small amount of fine powder, characterized in that the air is discharged from an exhaust port provided near the upper portion of the tank.

  Another aspect of the present invention is a tank for storing synthetic resin pellets, a supply port for supplying the synthetic resin pellets to the tank, an exhaust pipe provided near the upper part of the tank, and a synthetic resin pellets provided near the lower part of the tank. A synthetic resin comprising: a pipe, a pellet circulation pipe connecting the vicinity of the tank lower part and the vicinity of the tank upper part, a pressurized air introduction pipe connected to the pellet circulation pipe, and an ion generator provided in the pellet circulation pipe It is in the device for removing fine particles of pellets.

  According to the present invention, it is possible to obtain high-quality pellets with a very small amount of fine powder attached. By using such pellets, it is possible to prevent various problems caused by fine powder in the pellets during the molding process, such as, for example, meterability at the time of product molding, molding cycle characteristics, deterioration of the molded product surface appearance, etc. In addition, according to the present invention, since the pellet is repeatedly conveyed in the air flow through the pellet circulation pipe, a portion (whisker-like or burr-like portion) that tends to become fine powder from the pellet is removed due to friction and impact during this period. Therefore, the pellet from which fine powder has been removed according to the present invention is less likely to generate fine powder during subsequent handling.

Hereinafter, the present invention will be described in detail.
In the present invention, the pellets contained in the tank are circulated and moved so that they are extracted from the vicinity of the lower part of the tank through the pellet circulation pipe and returned to the tank in the vicinity of the upper part of the tank by airflow conveyance, and ions are generated in the moving pellets. Neutralize and remove the static electricity from the pellets by contacting the ions from the vessel. Thereby, the fine powder charged and adhered to the pellet is detached from the pellet. Since the separated fine powder floats in the tank, the fine powder in the floating state is brought into the air from the exhaust port provided in the vicinity of the upper portion of the tank and guided outside the tank. Thereby, the fine powder adhering to the pellets in the tank is removed.

Any ion generator can be used as long as it generates positive ions and / or negative ions to neutralize and remove static electricity from the pellets. Preferably, an electrode needle and a power source applied to the electrode needle are used. And a pulse-type ion generator that periodically generates positive ions and / or negative ions from one or a plurality of electrode needles. The amount of ions generated from this ion generator detects the surface potential of the object to be neutralized, thereby applying a voltage to automatically calculate the point at which the surface potential of the object becomes zero, and the amount of ions necessary for static elimination is appear. When this ion generator is used, neutralization and removal of charges can be performed in a very short time. Among them, the pulse AC type in which positive ions and negative ions are periodically and alternately generated from one electrode needle is preferable because of good ion balance. As the type of the ion generator, any of a blower type, a bar type, a spot type and the like can be used, but a spot type is preferable because it can be easily installed in a relatively narrow pellet circulation pipe. Examples of such ion generators include a bar AC type SJ-R series and a pulse AC type spot type SJ-M series commercially available from Keyence Corporation. In view of the large amount of generation, the spot AC type SJ-M series is preferable.

In the present invention, neutralization and removal of the static electricity of the pellet is performed by bringing the ions generated from the ion generator into contact with the pellet in the pellet circulation pipe.
The ion generator can be installed in any place as long as ions can be efficiently supplied to the pellets in the pellet circulation pipe. Usually, it is installed in a pellet circulation pipe having a diameter smaller than that of the tank because the processing efficiency is better than that in a tank having a large diameter.
Installation of the ion generator is not limited to one place, and it can be installed at two or more places, for example, near the lower part of the pellet circulation pipe and two places near the upper part as desired, and also provided in the middle of the pellet circulation pipe. You can also. Preferably, the ion generator is installed near the outlet of the pellet circulation pipe near the upper part of the tank. As a result, the neutralized and neutralized pellets are immediately discharged from the narrow pellet circulation pipe to the wide space of the tank, so that the pellets are again charged by friction and impact in the pellet circulation pipe to prevent the fine powder from being adsorbed. be able to. The ion generator is installed so that the pellets are released into the tank within 3 seconds, preferably within 1 second, more preferably within 0.5 seconds, especially within 0.1 seconds after contact between the ions and the pellets. It is preferable to do this. Although the position depends on the flow rate of the pellet, it is generally within 100 cm, further within 50 cm, particularly 20 to 50 cm from the outlet of the pellet circulation pipe near the top of the tank.

An example of the method for removing fine particles of pellets in the present invention will be described with reference to FIG.
FIG. 1 shows an example of a pellet fine powder removing apparatus used in the present invention. The fine powder removing device includes a tank 10 for storing pellets, an exhaust pipe 20 provided near the upper part of the tank 10, a pellet supply pipe 102 provided near the upper part of the tank 10, and a pellet provided near the lower part of the tank 10. An extraction pipe 30, a pellet circulation pipe 101 connecting the vicinity of the lower part of the tank 10 and the vicinity of the upper part of the tank 10, a pressurized air introduction pipe 103 provided in the pellet circulation pipe 101, and an ion generator 40 provided in the pellet circulation pipe 101. I have.

The pellets in the tank 10 are air-flowed through the pellet circulation pipe 101 by the pressurized air supplied upward from the pressurized air introduction pipe 103 to the pellet circulation pipe 101 and are released into the tank 10 in the vicinity of the upper part of the tank 10. . During this time, ions from the ion generator 40 come into contact with the pellets to neutralize and remove the charges, and the adhering fine powder loses its adhesive force and leaves the pellets. The neutralization of charges by the ion generator 40 is preferably performed so that the charge amount of the pellets in the tank 10 is 5 kv or less, particularly 3 kv or less. As shown in the figure, the pellet circulation pipe 101 is composed of a lower pipe extending obliquely downward from the tank 10 and an upper pipe extending upward from the lower end thereof, and a pressurized air introduction pipe 103 is connected to the lower end of the upper pipe. Is preferred. In this way, the pellets reach the pellet circulation pipe 101 so as to fall from the tank 10 to the lower pipe, and the dropped pellets are quickly conveyed upward by the pressure air flow. Supply is performed smoothly, which is preferable. The lower pipe extending obliquely downward from the tank 10 is attached so that the acute angle formed by the inclined part below the tank 10 and the lower pipe is preferably 60 degrees or less, more preferably 50 to 25 degrees.

  The material of the tank 10, the pellet circulation pipe 101, the pressurized air introduction pipe 103 and the pellet extraction pipe 30 and the material of the pellet supply pipe 102 to the tank 10 are not particularly limited, but stainless steel is preferable. For example, SUS304, SUS316, SUS403, etc. in JIS standard are mentioned. The air flow rate in the pellet circulation pipe 101 may be a speed at which the pellets are conveyed by airflow, but is usually 10 to 30 m / s. In order to sufficiently remove fine powder, the pellets in the tank should be repeatedly passed through the pellet circulation pipe 101. Usually, sufficient fine powder can be removed by repeating 3 to 4 times. . In addition, by circulating the pellets in this way, there is an effect of mixing the pellets in the tank, and the variation with time can be made uniform. The inner diameter of the pellet circulation pipe 101 is appropriately selected in consideration of the amount of pellets to be circulated, the flow rate to be conveyed, the contact efficiency with ions from the ion generator 40, and the like. For example, when transported at the above speed, the inner diameter is preferably 50 to 110 mm, and more preferably 60 to 80 mm. The air introduction pipe usually has an inner diameter equivalent to that of the pellet circulation pipe 101, but is appropriately selected in consideration of the capacity of the compressor, the introduction air pressure, and the like.

In a preferred embodiment of the present invention, the fine powder according to the present invention is removed by incorporating into a pellet manufacturing process by a conventional method. That is, in the production of pellets by a conventional method, a synthetic resin blended with various additives as desired is melt-kneaded, extruded into a strand form from an extruder, and cut into pellets. The obtained pellets are dried as necessary, or after removing foreign substances and non-standard products, and then sent to the tank as a product. In a preferred embodiment of the present invention, pellets are continuously supplied from the pellet supply pipe 102 to the tank 10 and the pellets are continuously taken out from the pellet extraction pipe 30 and sent to the product tank using the fine powder removing apparatus of FIG. . In the tank 10, 1.5 to 3 times the amount of pellets supplied to the tank 10 per hour is retained, and the pellets are subjected to fine powder removal operation by the method of the present invention. In the case of this continuous operation, the pellet supply pipe 102 is joined to the pellet circulation pipe 101 before the ion generator 40 so that the ions supplied from the ion generator 40 also come into contact with the pellet supplied to the tank 10. It is also preferable to make it.

  In this invention, the fine powder adhering to the pellet which consists of arbitrary synthetic resins can be removed. For example, general-purpose thermoplastic resins such as polyethylene and polypropylene, polycarbonate resins, polyester resins, polyphenylene ether resins, polyamide resins, polyacetal resins and other so-called engineering plastics, and pellets made of these resins and the like can be targeted. In addition, these resins include inorganic fillers such as glass fibers, glass flakes, carbon fibers, metal fibers (for example, potassium titanate whiskers), mica and talc, titanium oxide, silica, alumina, carbon black, and calcium carbonate. Commonly used for thermoplastics such as fillers, and, if desired, colorants, antioxidants, UV absorbers, mold release agents, impact modifiers, lubricants, antiwear agents, antistatic agents, etc. The thing which mix | blended the additive used can also be made into object.

Of course, it is preferable that the amount of the fine powder adhered to the pellet is small, but if the fine powder removing apparatus of the present invention is used, in the case of the reinforcing fiber-containing pellet containing glass fiber or carbon fiber, 0.1% of the pellet. It can be made into weight% or less. Depending on the composition, it may be 0.05% by weight or less. In the case of non-reinforced pellets, the amount of fine powder attached is usually smaller than that of reinforcing fiber-containing pellets, so the amount attached can be 0.03% by weight or less, although depending on the composition, it is 0. It can also be less than 01% by weight. By setting it as such fine powder amount, the deterioration of the measurement property at the time of shaping | molding and a shaping | molding cycle can be suppressed, and the external appearance of the molded article obtained tends to be excellent.

  Pellet made of reinforced thermoplastic resin composition containing reinforcing filler such as glass fiber, carbon fiber and glass flake, and inorganic filler such as titanium oxide and silica, especially pellets with high content of these fillers are pellets Due to the cutting of strands during production, contact between pellets being transported to the tank or between pellets and piping, etc., fine filler particles on the cut surface of the pellets are peeled off, and fine powder is easily generated. Since the amount of fine powder generated is larger than that of the non-reinforced thermoplastic resin composition not included, the effect of the present invention is particularly exerted.

The present invention will be described more specifically with reference to the following examples. In addition, this invention is not limited to a following example, unless the meaning is exceeded.
The fine powder charge-removing device used in the examples and comparative examples was the following (1), and the charge removal of the pellets was performed using the ion generator (2) below. Moreover, the measurement of the amount of electrification of the pellet and the amount of fine powder in the pellet was based on the following (3) and (4), respectively.

(1) Fine powder removing device:
The same fine powder removing device as in FIG. 1 was used. That is, the tank 10 for containing the pellets, the exhaust pipe 20 provided in the upper part of the tank 10, the pellet take-out pipe 30 provided in the vicinity of the lower part of the tank 10, and the inner diameter of 65 mm connecting the vicinity of the lower part of the tank 10 and the upper part of the tank 10 The pellet circulation pipe 101, the pressurized air introduction pipe 103 provided in the circulation pipe 101 near the lower part of the tank 10, the ion generator 40 provided 20 cm before the opening of the upper part of the tank 10 of the pellet circulation pipe 101, and the tank 10 It consists of a pellet supply pipe 102 opened at the top.

(2) Pellet static elimination method:
As an ion generator, SJ-M020 (manufactured by Keyence Co., Ltd.) (pulse AC spot type with one electrode needle) is used, and positive ions and negative ions are periodically generated at an output voltage of 5.5 kv and a pulse period of 33 Hz. The ions were alternately generated, and the ions were supplied to and contacted with the pellets moving in the pellet circulation pipe 101 to remove electricity.

(3) Method for measuring pellet charge amount:
A high-precision electrostatic sensor SK-030 manufactured by Keyence Corporation was used. Apply a voltage to the surface potential sensor while changing it stepwise, and calculate the point at which the potential difference from the object becomes zero. S. S. It is measured by the method, and it is not affected by the measurement distance and has high accuracy.

(4) Method for measuring the amount of fine powder in the pellet:
200 g of pellets after static elimination extracted from the pellet take-out tube 30 were applied to a screen-type automatic vibration sieving machine, the pellets and fine powder were separated, and the weight of the pellets from which fine powder was removed and the separated fine powder were measured. From the weight of both obtained, the fine powder adhesion amount of the pellet after static elimination was calculated | required. In addition, regarding the pellet before static elimination, the value obtained by subtracting the weight of the pellet to which fine powder has adhered before static elimination and the weight of the pellet from which fine powder has been removed after the static elimination calculated by the above method is defined as the fine powder weight, Asked.

Example 1
A resin composition comprising 69 parts by weight of polycarbonate resin, 30 parts by weight of glass fiber, and 1 part by weight of additives (stabilizer, mold release agent and colorant) was kneaded in an extruder at a temperature of 260 to 320 ° C. They were combined, extruded from a die at the tip of the extruder into a strand shape, cut and pelletized. The glass fiber was side fed from the middle of the extruder. The obtained pellets were removed from the non-standard shape and size of pellets and fine powders such as chips and crushed pieces by a pellet sorter equipped with 3 mm and 1.5 mm punching metal, and the pellet length was 3.0. The pellets were ± 0.4 mm and pellet diameter 2.9 ± 0.4 mm. Next, the fine powder was further removed from the pellets by a vibrating screen equipped with a punching metal of 2 to 3 mm, and then metal components were removed through a metal remover, and the pellets were conveyed from the pellet supply pipe 102 to the tank 10 by pneumatic feeding. The pellet supply amount was 330 kg / hour, and the pellet amount in the tank 10 was adjusted to always be 550 kg.

Using the fine powder removing apparatus shown in the above (1), air was introduced into the circulation pipe 101 from the pressure air introduction pipe 103 at a speed of 5.5 m ³ / min, and the pellets were circulated at 16.7 kg / min. Ions generated from the ion generator 40 were brought into contact with the circulating pellets under the conditions shown in (2) above, and neutralized and neutralized. When measuring the charge amount of the pellet before neutralization transported from the pellet supply pipe 102 into the tank 10 and the pellet after neutralization taken out from the pellet extraction pipe 30, the pellet before neutralization was 11 kv, The charge amount of the pellet after static elimination was 3 kv. Further, the amount of fine powder adhered to the pellet before static elimination at the inlet of the tank 10 supplied from the pellet supply pipe 102 was 0.0875 wt%. The amount of fine powder adhering to the pellets after charge removal taken out from the pellet take-out tube 30 was 0.0202% by weight, and it was found that 77% by weight of the fine powder was removed.

Comparative Example 1
In Example 1, it carried out like Example 1 except not having installed ion generator 40. The charge amount of the pellets supplied from the pellet supply pipe 102 into the tank 10 was 11 kv, and the charge amount of the pellets taken out from the pellet take-out pipe 30 was 11 kv. Further, the amount of fine powder adhering to the supplied pellet is 0.0875 wt%, the amount of fine powder adhering to the pellet taken out from the pellet take-out pipe 30 is 0.0692 wt%, and the amount of pellet adhering fine powder is 21 by air circulation alone. It was found that only weight percent was removed.

Example 2
A resin composition comprising 99 parts by weight of a polycarbonate resin and 1 part by weight of additives (stabilizer, mold release agent and colorant) was prepared in the same manner as in Example 1 with a pellet length of 3.0 ± 0.4 mm and a pellet diameter. A 2.9 ± 0.4 mm pellet was produced, and fine powder was removed from this pellet in the same manner as in Example 1. The charge amount of the pellet before neutralization supplied from the pellet supply pipe 102 into the tank 10 was 9 kv, and the charge amount of the pellet taken out from the pellet extraction pipe 30 after the neutralization was 3 kv. Moreover, the fine powder adhesion amount of the pellets supplied to the tank 10 from the pellet supply pipe 102 is 0.0176 wt%, the fine powder adhesion amount of the pellets taken out from the pellet extraction pipe 30 is 0.0033 wt%, and the fine powder It was found that 81% by weight of was removed.

Comparative Example 2
In Example 2, it carried out like Example 2 except not having installed ion generator 40. The charge amount of the pellets supplied from the pellet supply pipe 102 into the tank 10 was 9 kv, and the charge amount of the pellets taken out from the pellet take-out pipe 30 was 9 kv. Further, the amount of fine powder attached to the supplied pellet is 0.022 wt%, the amount of fine powder attached to the pellet taken out from the pellet take-out pipe 30 is 0.019 wt%, and the amount of pellet attached fine powder is 14 by air circulation alone. It was found that only weight percent was removed.

Example 3
In Example 1, it carried out similarly to Example 1 except having provided the ion supply place from the ion generator 40 in front of the opening part of the tank 10 upper part of the pellet circulation piping 101 for 230 cm. The charge amount of the pellets supplied from the pellet supply pipe 102 into the tank 10 was 10.5 kv, and the charge amount of the pellets removed from the pellet extraction pipe 30 after the charge removal was 5 kv. Further, the amount of fine powder attached to the supplied pellet is 0.0809% by weight, the amount of fine powder attached to the pellet taken out from the pellet take-out tube 30 is 0.0376% by weight, and 54% by weight of the fine powder is It was found that it was removed.

The schematic of the fine powder removal apparatus in this invention.

Explanation of symbols

10: Tank 20: Exhaust pipe 30: Pellet extraction pipe 40: Ion generator 101: Pellet circulation pipe 102: Pellet supply pipe 103: Pressure air introduction pipe

Claims (9)

  The synthetic resin pellets contained in the tank are extracted from the vicinity of the lower part of the tank and returned to the tank in the vicinity of the upper part of the tank by the air flow through the pellet circulation pipe, and generated by the ion generator in the moving synthetic resin pellets. The fine powder that is charged and adhering to the synthetic resin pellet is detached from the synthetic resin pellet, and the fine powder that is separated from the synthetic resin pellet and floats in the tank is provided near the upper part of the tank. A method for producing synthetic resin pellets with less fine powder, characterized in that the air is entrained with air and guided outside the tank.   The synthetic resin extruded in the molten state from the extruder is cooled and solidified to obtain synthetic resin pellets, which are supplied to a tank, and a series of operations for taking out the synthetic resin pellets from which fine powder has been removed are continuously performed. A method of producing synthetic resin pellets with less fine powder, wherein the synthetic resin pellets contained in the tank are extracted from the vicinity of the lower part of the tank and returned to the tank in the vicinity of the upper part of the tank by the air flow through the pellet circulation pipe. The ion generated by the ion generator is brought into contact with the moving synthetic resin pellets, and the fine powder that is charged and adhered to the synthetic resin pellets is separated from the synthetic resin pellets. The small amount of fine powder is characterized in that the fine powder floating in Method for producing a synthetic resin pellets.   In the pellet circulation pipe, a pressure air introduction pipe is attached near the connection with the vicinity of the lower part of the tank, and the synthetic resin pellets are supplied from the pressure air introduction pipe and flow upward in the pellet circulation pipe. The manufacturing method of the synthetic resin pellet with few fine powders of Claim 1 or 2 characterized by moving the inside of pellet circulation piping. The pellet circulation pipe consists of a lower pipe that extends diagonally downward from the connection with the vicinity of the lower part of the tank, and an upper pipe that extends upward from the lower end of the lower pipe and connects to the vicinity of the upper part of the tank. The method for producing a synthetic resin pellet with less fine powder according to claim 3, wherein the synthetic resin pellet is attached to a lower end of a pipe. The ion generator is installed in the pellet circulation pipe so that the pellets are released to the tank within 0.5 seconds after the ions generated by the ion generator contact the moving synthetic resin pellets. The method for producing a synthetic resin pellet with less fine powder according to any one of claims 1 to 4, wherein: The ion generator has an electrode needle and a power source applied to the electrode needle, and is a pulsed AC spot type in which positive ions and negative ions are periodically and alternately generated from the electrode needle. A method for producing a synthetic resin pellet with less fine powder according to any one of claims 1 to 5. The method for producing a synthetic resin pellet with less fine powder according to any one of claims 1 to 6, wherein the synthetic resin pellet contains glass fiber or carbon fiber.   A tank containing synthetic resin pellets, a supply port for supplying synthetic resin pellets to the tank, an exhaust pipe provided near the tank upper part, a synthetic resin pellet extraction pipe provided near the tank lower part, a tank lower part vicinity and a tank upper part vicinity A fine powder removing device for synthetic resin pellets, comprising: a pellet circulation pipe connecting the two, a pressure air introduction pipe connected to the pellet circulation pipe, and an ion generator provided in the pellet circulation pipe.   The apparatus for removing fine particles of synthetic resin pellets according to claim 8, wherein the ion generator is provided at a position 20 to 50 cm from the outlet of the pellet circulation pipe near the upper portion of the tank.

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