JPS58125730A - Production of prefoamed particles and system therefor - Google Patents

Abstract

PURPOSE:Control with a metering feed pump and valves permits the constant feed of a treating agent into the foaming tank, then resin particles are mixed with the treating agent by means of stirring blades, thus producing the titled particles uniformly coated with a treating agent without denaturation in the treating agent and blocking. CONSTITUTION:The stirring blades 17 are made to rotate, a certain amount of foaming thermoplastic resin such as polystyrene resin is fed into the hopper 21 by means of a metering device 22, then the magnet valve 23 is opened to feed the resin particles into the foaming tank 10. After completion of feed, the operation of the piston pump 31 and valves 33, 34 are controlled by means of the control panel 35 to feed a certain amount of a treating agent from the tank 30 into the foaming tank 10, then steam is supplied from the pipe 13 to effect prefoaming under agitation with blades 17. When the foaming particles reach the level detector 4 by their volume expansion, the cylinder 15 operates to open the cover for exclusion 14, thereby foamed particles coated with the treating agent are taken out to the silo 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing pre-expanded particles,
This provides a method and apparatus suitable for obtaining pre-expanded particles uniformly coated with a processing agent, and by using the pre-expanded particles, cycle time can be shortened, such as by shortening the cooling process of heat foam molding. It is designed to make it possible to contribute to

Conventionally, for example, in hot foam molding in which expandable polystyrene resin particles are filled into a mold and heated and cooled to obtain a foamed molded product, pre-expanded particles are coated with a processing agent such as paraffin oil. This is used to shorten the cycle time, such as shortening the cooling time after molding and removing the mold from the hot mold without deformation.

By the way, as a coating method with the above-mentioned processing agent, a method is generally performed in which the processing agent is mixed together with expandable thermoplastic resin particles in a ribbon blender before the pre-foaming step in a foaming tank.

However, according to the above coating method, in the current situation where it takes a long time for pre-foaming and molding after coating with a treatment agent, the coated treatment agent may change in quality and become foamed particles with a lot of water adhesion. , or it causes problems such as frequent blocking, and also has disadvantages such as requiring a large number of man-hours for coating.
Improvements were requested.

Therefore, the present invention provides a method for producing pre-expanded particles that can solve the above-mentioned conventional drawbacks and satisfy the needs, as well as achieve uniform coating of a processing agent. In a method for obtaining pre-expanded particles by heating and expanding expandable thermoplastic resin particles supplied in a fixed amount using a heating medium, a treatment agent for the resin particles is transferred from a treatment agent tank to a control action of a metered supply pump and a solenoid valve. The method is characterized in that pre-expanded particles whose surfaces are coated with the treatment agent are obtained by supplying a fixed amount of the resin particles and the treatment agent into a foaming tank, and stirring and mixing the resin particles and the treatment agent with a stirring blade in the expansion tank.

Next, embodiments of the present invention will be illustrated below with reference to the drawings together with an apparatus for use thereof.

ill indicates the main body of a batch type prefoaming device which is the device used in this invention. Of these, (lO) is the foaming tank, (11
) is the steam room, (12) is the foaming tank (10) and hot air chamber (11).
) is a hot plate that separates the The hot plate (12) has many small holes (
(not shown) so that steam supplied from a steam supply pipe (13) can be injected into the foaming tank (10). (14) is A for extracting foamed grains, and is opened and closed by a cylinder (16). (161 is a silo that receives foamed particles. (17) is a stirring blade for foaming thermoplastic particles (hereinafter referred to as resin particles); 1111
11 (centering on 18+), the drive unit 119 rotates.

(2) is the lij supply part of the resin particles, of which (2
I+ is a pop, prisoner is! A quantitative meter is used to measure and supply a fixed amount of resin particles to the hopper (21), and an electromagnetic on-off valve is used to supply the resin particles supplied to the hopper (21) to the foaming tank 1 []1.

(3) is a quantitative supply device that supplies a processing agent such as paraffin oil to the resin particles in the foaming tank (10).

Among them, (30) is a piston pump installed outside the foaming tank (10), and the processing agent tank (31) is a pump for quantitatively supplying the processing agent. The piston pump 1) has a piston (311) that reciprocates in a cylinder (9), and the suction port (31a) of the piston pump (31) is connected to the processing agent tank (30), and the discharge port (31b) is connected to the processing agent tank (30). Foaming tank (lO)
They are each piped to (33) is processing agent tank eo)
The foundation installed an electromagnetic valve in the suction line (X) from the metered supply pump (31) to the discharge line (Y) connecting the metered supply pump (31) to the foaming tank fio+. Each electromagnetic valve is shown. The above cylinder (
3 barrels and an electromagnetic valve (:+31 (341) are each controlled by a processing agent tank (111"control:4"!t 1331 so that the processing agent for paulownia can be supplied into the foaming tank 1101. In other words, the electromagnetic Valve (33+ +341 is
During the suction process of the piston pump el), the electromagnetic valve (331) on the suction line (X) side opens, and the discharge line (Y)
The side electromagnetic valve (34) is closed, and during the discharge process, its opening and closing are controlled to be reversed, and the other cylinder (321) is controlled to move forward or backward as appropriate in conjunction with the opening/closing control of the electromagnetic valves +331 +341. (+111 is added, so that the treatment agent can be sucked into the piston pump (31) and discharged to the foaming 1% (ltll side).The piston pump (31) accurately controls the discharge amount of the treatment agent. It is suitable as a fixed quantity supply pump that can inject the processing agent into
Place [14th move! It can be easily adjusted by adjusting the stroke of the hot water in the cylinder by adjusting l1ar, that is, by adjusting the stroke of the piston (31). (Jun is a nozzle for shower spray M''j installed at the supply port of the processing agent into the foaming W tlLlj.

In this nozzle, the above-mentioned supply of the processing agent to the foaming m tl (1 yen) is accomplished by shower jetting, and the processing agent can be uniformly supplied to the resin particles. The injection pressure is usually appropriately selected within the range of 0.5 to 6, taking into consideration the injection amount and injection durability.

(4) is a level detector installed at the top of the foaming tank (10), which detects the amount of foaming, that is, detects that the resin particles have reached the richness position of the level detector, and activates the cylinder 115 to discharge the foam. This is for opening the lid (14) and discharging the foam particles.

When carrying out the manufacturing method of the present invention using the apparatus of gd above, for example, Jugetsuma particles of polystyrene resin are used as the expandable thermoplastic resin particles, and stirring blades 11'7 are used.
! hopper 21 by the quantitative measuring device 122i.
After supplying a fixed amount of resin particles into 1, the electromagnetic closing valve 1
, 231 is opened to supply the resin particles into the foaming tank (10), and after the supply into the foaming Pmiol is completed, a fixed amount of the treatment agent is showered into the foaming tank (1o) using the piston pump (31). Then, steam is supplied from the steam supply pipe (13) into the foaming tank (10i), and preliminary foaming is performed while stirring and mixing the resin particles and the processing agent. When the container (4) has reached the stage, open the discharge lid (14) as described above and transfer the foamed grains to the silo (
16). Therefore, the resin particles can be coated with the treatment agent easily and uniformly using stirring in the foaming tank (IO).

As an example of the above manufacturing method, one
After supplying a fixed amount of 0KF resin particles and putting them into the foaming tank (10), 60 sprays of paraffin oil as a processing agent were injected to foam 50 times, resulting in an even and uniform coating of the processing agent. Pre-expanded particles were obtained.

In addition, regarding heat foam molding using pre-expanded particles coated with the above-mentioned treatment agent, the pre-expanded particles were aged for 24 hours and molded into 60u x 400 WM x 4.
As a result of molding a plate material of 00 fi, the cooling time required by the method of this invention was 18 seconds, compared to 25 seconds when using general pre-expanded particles without coating.
It only took a few seconds, significantly reducing the cooling time. Furthermore, the molded product was in good condition with no shape deformation despite being released at a total mold temperature of approximately 70°C, making it clearer that the treatment agent coating was more uniform than ever before. The timing of supplying the treatment agent and steam in the above-mentioned manufacturing method is to supply the treatment agent after the supply of resin particles into the foaming tank (10) is completed, and to supply the steam after the completion of quantitative supply of the treatment agent. In addition to the above-mentioned embodiment of supply, there is a method in which the processing agent is simultaneously supplied before the supply of the resin particles is completed, and steam is supplied after the supply is completed, or the processing agent is supplied after the supply of the resin particles is completed. Various methods can be selected and implemented, such as a method of simultaneously supplying steam while the treatment agent is being supplied, and a method of simultaneously supplying the resin particles, the treatment agent, and the steam with respective time lags set. However, in either method, it is desirable to rotate the stirring blade θ force before supplying the resin particles. Furthermore, the treatment agent may be sprayed continuously or intermittently. As for the spraying method, in addition to the shower spraying method mentioned above, a mist spraying method is sometimes used by installing a nozzle for mist spraying at the supply port. It is also possible to carry out the injection by gravity-dropping without the use of water.

In addition, as the resin particles used in this invention, in addition to the polystyrene resin mentioned above, other resins such as polyethylene resin can be used to achieve the same effect as described above, and batch-type preliminary preparation is possible. Various types of foaming devices can also be used.

This invention is constructed as described above, and a treatment agent is supplied in a fixed amount to the resin particles in the supplied foaming tank (10), and the two are stirred and mixed to pre-foam, and the resin particles coated with the treatment agent are pre-foamed. Because of the method of obtaining foamed particles, there is no need for the conventional coating process using a ribbon blender, and there are also problems such as deterioration of the processing agent, resulting in foamed particles with a lot of water adhesion, or frequent blocking. This can be resolved. In addition, mixing the processing agent and resin particles,
This method utilizes the conventional stirring using a stirring blade (1'7), and does not require any special equipment.
The mixing can be carried out extremely easily, and since the above-mentioned stirring sufficiently mixes the treatment agent and the resin particles with the side walls, the treatment agent can be evenly and uniformly coated on the legs. This will further contribute to shortening the cycle time, such as shortening the cooling time in hot foam molding and removing the mold from the mold at high temperatures.

In addition, as a device for quantitatively supplying the processing agent, a piston pump (311 is used as a quantitative supply pump, and a solenoid valve is installed in the inflow system (X) and the discharge system (Y) of the processing agent to the piston pump ml), respectively. (33) and (34) are installed to operate the electromagnetic valve (331 (341 and quantitative supply pump 01), which has a very simple structure and can supply an accurate amount of processing agent, and its manufacturing cost is low. It is also inexpensive and suitable for further increasing the cost reduction effect of implementing the method for producing pre-expanded particles according to the present invention.

[Brief explanation of the drawing]

The figures illustrate embodiments of the invention and show cross-sectional views of equipment used in the practice of the invention. itl... Main body of pre-foaming device, (101... Foaming tank, (14)... Discharge lid, 07)... Stirring blade,
(2)... Bead supply section, 1)... Hopper,
(22...Quantitative measuring device, (3)...Processing agent quantitative supply device, ta++...Piston pump, (34...Cylinder, (4)...Level detector. Procedural amendment document stamped) Showa June 23, 1957 Mr. Haruki Shimada, Commissioner of the Japan Patent Office", :, -";+'1, °゛υ 1 Display of case Relationship to Patent Application No. 9088 of 1988 Patent applicant 4, agent 5 Date of amendment order (voluntary) 6. Number of inventions increased by amendment 7. Subject of amendment (1) Specification disciple pages 1 to 2 negative claims are corrected as shown in the attached sheet. (2) Same as before The description of "metered supply pump and electromagnetic pulp" in line 10 of the 4th edition is corrected to "metered supply pump and pulp". (3) Add the following sentence between lines 13 and 14 of page 10 of the 4th edition. [Furthermore, in the quantitative supply device (3), even if a check valve is used in place of the electromagnetic valve, the discharge of the processing agent similar to that described above can be reduced by four times; in this case, This eliminates the need for electrical pulp control, making it possible to further simplify the structure.'' (4) Same as before, page 11, lines 15 to 17, ``Each electromagnetic valve C33 (b) is provided, and the electromagnetic valve (To) The description in ``This is a system that operates the metered supply pump 6υ along with the control of (■),'' has been changed to ``The processing agent is supplied by controlling the nozzle and operating the metered supply pump 6υ.'' 2.Claim 1: A method for obtaining pre-expanded particles by heating and expanding expandable thermoplastic resin particles fed in a constant quantity into a foaming tank with a heating medium, in which a treatment agent for the resin particles is applied. The treatment agent is supplied in a fixed amount from the treatment agent tank into the foaming tank by the control action of the metered supply pump 4 loops, and the resin particles and treatment agent are stirred and mixed with a stirring blade in the foaming tank, so that the treatment agent is applied to the surface. 2. A method for producing pre-expanded particles according to claim 1, wherein the pre-expanded particles are coated with pre-expanded particles. 3. The method for producing pre-expanded particles according to claim 1, wherein the treatment agent is supplied in a fixed quantity by injection. 4. The expandable thermoplastic resin particles supplied in a fixed quantity in a foaming tank are heated with a heating medium. In a batch-type pre-foaming device that expands and obtains pre-expanded particles, a piston/pump is piped as a metered supply pump to a treatment agent tank provided outside the foaming tank, and a metered supply suction system is connected from the treatment agent tank. , the discharge line ρ connecting the metering pump to the foaming tank
1. An apparatus for producing pre-expanded particles, characterized in that a pre-expanded particle manufacturing apparatus is provided with respective valves, and a fixed amount of processing agent can be supplied into a foaming tank by controlling these pulps and operating a fixed-rate supply pump 19. 5. The apparatus for producing pre-expanded particles according to claim 4, wherein a nozzle for shower spraying or mist spraying is provided at the supply port of the treatment agent into the foaming tank.

Claims (1)

[Claims] 1. In a method for obtaining pre-expanded particles by heating and expanding expandable thermoplastic resin particles supplied in a fixed amount into a foaming tank with a heating medium, a treatment agent for the resin particles is removed from a treatment agent tank. The resin particles and the treatment agent are agitated and mixed in the foaming tank using a stirring blade, with a constant amount supplied into the foaming tank by the control action of a metering pump and an electromagnetic valve. A method for producing pre-expanded particles, characterized by obtaining expanded particles. 2. The method for producing pre-expanded particles according to claim 1, wherein the treatment agent is supplied in a fixed quantity by injection. 6. The method for producing pre-expanded particles according to claim 1, wherein the treatment agent is supplied in a fixed quantity by injection. 4 In a batch-type pre-foaming device that obtains pre-expanded particles by heating and expanding expandable thermoplastic resin particles supplied in a fixed amount into a foaming tank using a heating medium, a piston pump is used to supply a fixed amount of foamable thermoplastic resin particles to a processing agent tank provided outside the foaming tank. Piping is installed as a supply pump, and a solenoid valve is installed in the suction line from the processing agent tank to the metered supply pump, and a solenoid valve is installed in the discharge line connecting the metered supply pump to the foaming tank. 1. An apparatus for producing pre-expanded particles, characterized in that a pump is operated to supply a fixed amount of processing agent into a foaming tank. 5. The apparatus for producing pre-Mi+ foamed particles according to claim 4, wherein a nozzle for shower spraying or mist spraying is provided at the supply port of the treatment agent into the foaming tank.