JP2006218832A - Granulation method for foamed material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a granulation method for a foamed material which can give a granulated product with uniform granules while ensuring excellent cushioning properties by performing the granulation in the condition that the foamed material is blended in a larger amount. <P>SOLUTION: The granulation method comprises blending foam chips consisting of a thermosetting resin such as a urethane resin and thermoplastic resin pellets consisting of a polyethylene and the like and granulating the blend while compressing. By this granulation method using the foamed material, even if the foamed material are formulated in a larger amount, it is possible to obtain the uniform granular product excellent in cushioning properties. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a foam granulation method.

Conventionally, foams having elasticity, such as urethane foams, have been widely used in various industrial fields. Such a foam is desired to be reused from the viewpoint of reducing the environmental load.
For example, with respect to 20 to 70% by weight of the pulverized resin to be processed having an increased bulk specific gravity obtained by pulverizing a thermosetting resin foam, 30 to 80% by weight of a thermoplastic resin is mixed, gelled and kneaded, and granulated. A method of obtaining a recycled resin by granulating to a diameter of 15 mm or less has been proposed (for example, see Patent Document 1).
JP-A-9-66527

However, in the method described in Patent Document 1, uniform granulation can be obtained by blending and granulating less thermosetting resin foam than thermoplastic resin. However, since the obtained granulated material has a low blending ratio of the thermosetting resin foam having elasticity, there is a problem that the cushion performance is low.
On the other hand, if the thermosetting resin foam is blended in a larger amount than the thermoplastic resin and granulated, the cushion performance is not lowered, but there is a problem that the granulated body becomes extremely uneven.

  An object of the present invention is to provide a foam granulation method that can obtain a uniform granular granule while ensuring excellent cushioning performance by blending and granulating more foam. It is to provide.

The foam granulation method of the present invention is characterized in that a foam and a thermoplastic resin are blended and granulated while being compressed.
In the foam granulation method of the present invention, it is preferable that the foam is a urethane foam.
In the foam granulation method of the present invention, it is preferable that the thermoplastic resin is a polyethylene resin.

  Moreover, in the granulation method of the foam of this invention, it is suitable to mix | blend 40 weight part or less of the said thermoplastic resin with respect to the total amount of the said foam and the said thermoplastic resin.

  According to the foam granulation method of the present invention, even if more foams are blended and granulated, a uniform granular granule can be obtained. Therefore, it can be reused in various applications as a uniform granular granule having excellent cushion performance.

The foam granulation method of the present invention blends a foam and a thermoplastic resin and granulates while compressing.
The foam is not particularly limited as long as it is a thermosetting foam. For example, foamed polyurethane foam, polyamide foam, polyphenol foam, polyxylene foam, unsaturated polyester foam, epoxy foam, etc. The body is used. Preferably, a polyurethane foam is used from the viewpoint of elastic properties.

Such a foam is a used one or an unnecessary part (chip or the like) generated during molding of the foam. If necessary, for example, the foam is pulverized to about 1 to 5 mm by a pulverizer. It is done.
These foams are appropriately used alone or in combination.
The thermoplastic resin is not particularly limited, and for example, crystalline or semi-crystalline such as polyethylene resin, polypropylene resin, ethylene-propylene copolymer resin, polyacrylonitrile resin, polyethylene terephthalate resin, polylactic acid resin, polycarbonate resin, etc. A thermoplastic resin such as an amorphous thermoplastic resin such as a polystyrene resin, a polyvinyl chloride resin, or a polymethyl methacrylate resin is used. Preferably, a polyethylene resin is used from the viewpoint of the glass transition temperature.

The thermoplastic resin is not particularly limited, and is used as, for example, a pellet.
These thermoplastic resins are used alone or in combination as appropriate.
Next, one embodiment of the foam granulation method of the present invention will be described with reference to FIG.
FIG. 1 is a side sectional view of an essential part showing an embodiment of a granulating apparatus used in the foam granulating method of the present invention, and FIG. 2 is a plan view thereof. 1 and 2, the granulating apparatus 1 includes a tank 2, a rotary blade 3, a motor 4, a pressing mechanism unit 5 and a CPU (not shown), and a support frame 14 thereof.

The tank 2 is installed on the support frame 14 and has a bottomed cylindrical shape that is open at the top to receive the material. The upper opening has an upper lid 7 that covers the opening, and a lower side. Is provided with a discharge part 8 for discharging the granulated body.
The upper lid 7 is provided with a pressing mechanism portion 5. Further, the discharge portion 8 is provided with a discharge port 9 that is formed in communication with the tank 2 and is opened downward, and an open / close gate 10 for opening and closing between the discharge port 9 and the tank 2. Yes. A pressure cylinder 11 is connected to the open / close gate 10, and the open / close gate 10 is opened / closed by driving the pressure cylinder 11 back and forth.

The rotary blade 3 is provided at the bottom of the tank 2, and includes a rotary shaft 12 that penetrates the central portion of the bottom wall of the tank 2 in the vertical direction and a blade member 13 that is supported on the top of the rotary shaft 12. ing.
The lower part of the rotary shaft 12 is supported below the bottom wall of the tank 2 by a support frame 14 via a bearing 15 so as to be rotatable, and the upper part thereof protrudes into the tank 2. Further, in the support frame 14, a passive pulley 16 to which power from a motor 4 to be described later is transmitted is provided below the rotary shaft 12 so as not to be relatively rotatable.

Further, the blade member 13 is integrally provided with a base portion 17 fitted to the upper portion of the rotating shaft 12 and a plurality of blade portions 18 extending in the radial direction from the base portion 17. The blades 18 are arranged so as to extend radially from the bottom center in the tank 2.
The motor 4 is installed on the side of the tank 2 on the support frame 14, and its pinion shaft 19 is inserted into the support frame 14. Further, a transmission pulley 20 is provided on the pinion shaft 19 so as not to be relatively rotatable.

  An endless belt (not shown) is wound around the transmission pulley 20 provided on the pinion shaft 19 and the passive pulley 16 provided on the rotary shaft 12. Therefore, when the pinion shaft 19 is rotated by driving the motor 4, the power is transmitted to the rotating shaft 12 through the transmission pulley 20, an endless belt (not shown) and the passive pulley 16, thereby causing the blade member 13 to move. It is rotated in the tank 2.

As shown in FIG. 2, a plurality of (four) pressing mechanism portions 5 are provided along the circumferential direction from the center of the upper lid 7 in the state facing the rotary blade 3 in the upper lid 7 (hereinafter, each pressing In order to distinguish the mechanism parts 5 from each other, the first pressing mechanism part 5a, the second pressing mechanism part 5b, the third pressing mechanism part 5c, and the fourth pressing mechanism part 5d are set along the circumferential clockwise direction).
As shown in FIG. 1, each pressing mechanism 5 includes a casing 21, a cylinder 22, and a piston 23. The casing 21 has a substantially rectangular tube shape and is supported so as to stand upward from the upper lid 7. The lower end portion of the casing 21 is communicated with the inside of the tank 2 by opening the upper lid 7. ing.

The cylinder 22 is provided in the upper part of the casing 21, and supports the advance / retreat shaft 24 of the piston 23 described below so as to be able to advance and retreat.
The piston 23 is always housed in the casing 21, and an upper and lower shaft 24 whose upper end is connected to the cylinder 22, and a pressing portion that is provided at the lower end of the forward and backward shaft 24 and expands downward in a conical shape. 25.

  A compressor (not shown) is connected to the cylinder 22 of each pressing mechanism 5 via each pressure regulator (not shown) and each on / off switch (not shown), and the compressed air sent from the compressor. By turning on / off each on / off switch using (pressure air), when the on / off switch is on, the piston 23 supported by the cylinder 22 is maintained at a predetermined pressure set by the pressure regulator. The advance / retreat shaft 24 is advanced from the casing 21 into the tank 2 and advanced to an advance position (indicated by a dotted line in FIG. 1) where the pressing portion 25 presses and compresses the material, and the on / off switch is turned off. Sometimes, the advance / retreat shaft 24 of the piston 23 is retracted from the advance position in the tank 2 and is accommodated in the casing 21. Retracted position and so as to advance and retreat in (as. For indicated by the solid line in FIG. 1).

A control program is stored in the CPU (not shown), and the advance / retreat operation of the piston 23 of each pressing mechanism unit 5 is performed along the circumferential direction of the tank 2 by the control program. Control is performed so that the basic operation in which the pistons 23 of the pressing mechanism 5b, the third pressing mechanism 5c, and the fourth pressing mechanism 5d are selectively advanced and retracted one by one is repeated.
Thus, if the piston 23 of each press mechanism part 5 is advanced and retracted, the press part 25 will press and compress the material thrown into the tank 2 so that it may push into the rotary blade 3 from above. Therefore, the material can be efficiently compressed during the stirring of the material.

Next, a foam granulating method using the granulating apparatus 1 will be described with reference to FIG.
At the start of the granulation process, the motor 4 is first turned on by turning on the power and operating a switch on an operation panel (not shown). If it does so, the motor 4 will be driven by fixed rotation speed, and, thereby, the rotary blade 3 will be rotated by the corresponding circumferential speed.

The rotation speed of the motor 4 is, for example, 500 to 1800 min ⁻¹ , and the peripheral speed of the rotary blade 3 is set within a range of 20 to 50 m / sec, for example.
Next, the material is put into the tank 2. The materials are the above-mentioned foam and thermoplastic resin, and these are blended in the tank 2. Note that the order in which the tanks 2 are charged is not particularly limited.

The blending ratio of the foam and the thermoplastic resin is, for example, 40 parts by weight or less, preferably 30 parts by weight or less, with respect to the total amount of the foam and the thermoplastic resin. . If the amount of the thermoplastic resin is more than 40 parts by weight with respect to the total amount of the foam and the thermoplastic resin, the cushion characteristics of the resulting granulated body may be deteriorated.
Next, the control program stored in the CPU is executed by operating a switch on an operation panel (not shown). If it does so, each press mechanism part 5 will advance / retreat, and the advance / retreat operation | movement will be controlled.

  The input materials (foam and thermoplastic resin) are sheared and pulverized by the rotation of the rotary blades 3 while being pressed and compressed by the respective pressing mechanisms 5. Further, since the temperature in the tank 2 rises due to the shear heat of the rotary blade 3, the thermoplastic resin is softened and melted. On the other hand, since the foam is thermosetting, it is not softened and melted by the shear heat of the rotary blade 3, but the softened and melted thermoplastic resin adheres and aggregates. That is, in such a method, since the foam and the thermoplastic resin are blended and granulated while being compressed, the molten thermoplastic resin is deformed into a flat shape, and the adhesion area to the foam is increased. Therefore, even when the foam is blended more with respect to the thermoplastic resin, the foam with the thermoplastic resin adhering to the surface in this way is similar to the other foam with the thermoplastic resin adhered, Due to the adhesion between the plastic resins, they are efficiently aggregated together. Then, the thermoplastic resin can be granulated while being surely wound into the thermoplastic resin and kneaded. As a result, the thermoplastic resin can sufficiently exhibit the above-described binder function even when more foam is added. Therefore, a foam can be granulated reliably and a uniform granulated body can be obtained.

  In addition, when granulating without compression, the thermoplastic resin simply melts and adheres to the surface of the foam, and when the foam is blended more with the thermoplastic resin. The thermoplastic resin does not perform the binder function, and the foam to which the thermoplastic resin adheres does not agglomerate with each other, and is not granulated simply by rotating in the tank 2. Can't get.

Thereafter, when the temperature in the tank 2 is detected by the temperature sensor as a predetermined temperature, the granulation is completed, and the motor 4 is turned off by the switch on the operation panel, and the advancing / retreating operation of each pressing mechanism unit 5 is finished. . Note that the granulation completion time point may be a time point when it is visually confirmed that the granulation is completed.
And after granulation, if the granulated body is discharged from the discharge port 9 by operating the pressure cylinder 11 to open the open / close gate 10, the uniform granular granulated body having a uniform particle diameter. Can be obtained.

The granule obtained in this way is superior in cushioning performance because the foam is more blended with the thermoplastic resin. Therefore, it can be suitably reused as a cushion filling or cushion material that requires cushion performance.
In addition to the foam and thermoplastic resin described above, metal powder may be added as a material. Examples of the metal include ferromagnetic metals such as iron, iron oxide, cobalt, and nickel, for example, paramagnetic metals such as manganese, chromium, platinum, titanium, and palladium, such as ferromagnetic metals and paramagnetic metals. An alloy of a magnetic material with a metal is used. The particle size of these metal powders is 0.01-3000 micrometers, for example.

The compounding ratio of the metal powder is, for example, 10 to 500 parts by weight with respect to 100 parts by weight of the total amount of the foam and the thermoplastic resin.
The charging of the metal powder may be performed at an appropriate timing during the granulation at the same time as or after the charging of the foam and the thermoplastic resin, and is appropriately determined.
By introducing the metal powder in this way, the granulated foam can be made to contain the metal powder uniformly. For example, after granulation, the metal powder is magnetized, etc. It can be reused as a filling or cushioning material.

Further, in the above method, the timing for operating the pressing mechanism unit 5 is determined when the temperature in the tank 2 rises due to the crushing shear of the rotary blade 3 and is detected by the temperature sensor in the tank 2. You can also
In the above description, the advance / retreat operation of the piston 23 of each pressing mechanism 5 is performed along the circumferential direction of the tank 2 by the control program stored in the CPU. Control is performed so that the basic operation in which the pistons 23 of the mechanism portion 5b, the third pressing mechanism portion 5c, and the fourth pressing mechanism portion 5d are selectively advanced and retracted one by one is repeated. The advancing / retreating operation of the piston 23 is not particularly limited. For example, the operations of advancing and retracting the first pressing mechanism unit 5a and the third pressing mechanism unit 5c simultaneously and the second pressing mechanism unit 5b and the fourth pressing mechanism unit 5d are alternately performed. You may make it repeat. Further, the piston 23 of each pressing mechanism 5 may be selectively advanced and retracted so that at least one of the pistons 23 is always retracted.

In the granulation apparatus 1 described above, four pressing mechanisms 5 are provided in the circumferential direction, but the number and arrangement thereof are not particularly limited, and may be appropriately determined depending on the size of the apparatus.
In the above description, each pressing mechanism 5 is configured to move the piston 23 forward and backward by compressed air from the compressor 29. However, the piston 23 is not limited to this, and may be, for example, a hydraulic mechanism or a jack. You may make it move forward / backward by a mechanism or the like.

Example 1
Using the granulator shown in FIGS. 1 and 2, the polyurethane foam, polyethylene resin and iron powder were blended and granulated.
First, the power of the granulator was turned on and the motor was turned on to rotate the rotating blades (circumferential speed, 20 m / sec).

Next, 1.5 kg of polyurethane foam chips (bulk density, 0.2 g / cm ³ ) and 1.0 kg of polyethylene resin pellets (bulk density, 0.42 g / cm ³ ) were used as materials. It was put into the tank.
Thereafter, each pressing mechanism was advanced and retracted by the CPU, the material was compressed, and the polyurethane foam and the polyethylene resin were stirred and granulated while being compressed. Four minutes after the start of granulation, when the temperature in the tank reached 110 ° C., 1.0 kg of iron powder (bulk density, 3.66 g / cm ³ ) was added to the tank, and granulation was continued. Twelve minutes after the start of granulation, the temperature in the tank reached 170 ° C, so the motor was turned off, the control of the CPU's pressing mechanism was turned off, and the stirring of the rotating blades and the compression of each pressing mechanism were terminated. The granulation was completed. After cooling, the open / close gate was opened, and the granulated material was discharged from the discharge port to obtain a granulated material.

  The obtained granulated body was uniform particles containing iron powder uniformly and had good cushioning properties.

It is a whole lineblock diagram showing one embodiment of a granulation device of the present invention. It is a top view of the granulation apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Granulator 2 Tank 3 Rotary blade 5 Pressing mechanism part

Claims (4)

A foam granulating method comprising blending a foam and a thermoplastic resin and granulating the mixture while compressing. The method for granulating a foam according to claim 1, wherein the foam is a urethane foam. The method for granulating a foam according to claim 1 or 2, wherein the thermoplastic resin is a polyethylene resin. The granulation method for a foam according to any one of claims 1 to 3, wherein 40 parts by weight or less of the thermoplastic resin is blended with respect to a total amount of the foam and the thermoplastic resin.

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