JPH0524319U - Thermoplastic resin foam volume reduction device - Google Patents

Abstract

(57) [Abstract] [Purpose] The structure is simple and the device itself can be downsized, and the volume reduction processing speed of the foam is fast. A suitable thermoplastic resin foam volume reducing device is provided. A device for compressing a thermoplastic resin foam 4 placed between two pressure plates 2 and 3 facing each other to reduce the volume of the thermoplastic resin foam 4, the pressure plate 2,
A heating plate 10 for heating 3 is provided, and at least one pressure plate is provided with a pressing device 5 for pressing and compressing the thermoplastic resin foam 4 while heating.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a volume reducing device for reducing the volume of a thermoplastic resin foam.

[0002]

[Prior Art]

 Recently, thermoplastic resin foams are widely used in trays used for food packaging, cushioning materials, etc., but these foams are recovered and melted and reused from the viewpoint of effective use of resources. Is required to do so. As a system for reusing thermoplastic resin foams, for example, a collection station is a place that sells products that use trays such as supermarkets, and used trays are collected from consumers. However, the used trays, etc., collected at each collection station as described above when the consumer is actively in the collection station, are large-scale equipment equipped with various plastic sorting, crushing, washing, and drying facilities. A method of carrying out intensive melt regeneration treatment by being transported to a reprocessing center equipped with a plastic melting regenerator, etc. has been proposed as a means for further increasing recovery efficiency. By the way, when the foam collected at the collection station is transported to the processing center, there is a problem in that the foam has a low density and is very bulky, which causes a high transportation cost. Therefore, it is important to reduce the volume of the foam (reduce volume) in advance at the collection station etc. to reduce the transportation cost, and it is necessary to install a foam volume reduction device for that at the collection station. As a conventional volume reducing device used for reducing the volume of this foam, a general plastic reprocessing device is known. For example, a plastic is placed in a container in which heated air or the like is circulated and heated and melted. There is known a device for reducing the volume, a device for heating the wall of the container like an extruder and extruding it by melting it by conduction heat.

[0003]

[Problems to be solved by the device]

 However, when attempting to reduce the volume of thermoplastic resin foam using conventional equipment, when the equipment of is used, the heat conduction between the foam and the heating body is poor and the heat capacity of the heated gas is small, so especially for food trays. In the case of a foam having a relatively low expansion ratio and being easily overlapped with each other as described above, there is a drawback in that the efficiency itself is lowered and a large heat capacity is required, and the apparatus itself becomes large. Further, in the case of the above-mentioned extrusion type apparatus, it is necessary to make a large contact area with the heating body in order to melt the foam, and the foam to be treated in order to send the foam to the inside of the extruder. However, there is a problem in that it requires a crushing device, which complicates the device and requires a long processing time. As described above, the conventional general volume-reducing device for plastics is insufficient as a volume-reducing device for thermoplastic resin foam, and there is room for improvement. The device of the present invention is to solve the above problems, and has a simple structure, allows the device itself to be miniaturized, and has a high volume reduction processing speed of the foam, especially for food trays and the like. An object of the present invention is to provide a volume reducing device suitable for treating foams having a low expansion ratio (expansion ratio of 20 times or less).

[0004]

[Means for Solving the Problems]

 The thermoplastic resin foam volume-reducing device of the present invention is a device for compressing a thermoplastic resin foam placed between two opposing pressure plates to reduce the volume of the thermoplastic resin foam. A heating device for heating the pressure plate, wherein at least one of the pressure plates is provided with a pressurizing device for pressurizing and compressing the thermoplastic resin foam while heating. is there. Further, in the above apparatus, a groove or a recess for discharging the melted thermoplastic resin foam to the outside may be formed on the surface of at least one of the pressure plates.

[0005]

[Action]

 The operation of the device of the present invention will be described below. The moving pressure plate 2 and the fixed pressure plate 3 are heated by the heating plate 10, and when the moving pressure plate 2 is moved by the pressurizing device 5, the thermoplastic resin foam 4 placed between the pressure plates 2 and 3 is pressed. Since the resin is melted at the same time as it is contacted because it is strongly pressed against the plates 2 and 3 and is heated closely, the surfaces of the pressure plates 2 and 3 come into contact with the surfaces of the unmelted foam 4 one after another due to the pressure. The foam melts in a short time and the volume is reduced. Bubbles contained in the foam and air in the gaps between the foams escape to the outside from the side surfaces. Further, when a groove or a recess is provided on the surface of the pressure plate, the molten foam resin is discharged from the groove or the recess to the outside.

[0006]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention, and FIG. 1 is a sectional view showing an example of a volume reducing device for thermoplastic resin foam of the present invention. As shown in FIG. 1, the device 1 for reducing the volume of a thermoplastic resin foam according to the present invention includes a thermoplastic resin foam 4 mounted between two pressure plates, a moving pressure plate 2 and a fixed pressure plate 3, which face each other. A device for compressing to reduce the volume of the foam body 4, which comprises pressure plates 2, 3 on the back side of the moving pressure plate 2 and the fixed pressure plate 3 (the surface not in contact with the thermoplastic resin foam body 4). A hydraulic drive pressurizing device 5 for heating the thermoplastic resin foam 4 while heating it with the moving pressure plate 2 is connected to the moving pressure plate 2. In the present invention, the pressurizing device for pressurizing the pressure plates may be provided so that at least one of the pressure plates moves, but the two pressure plates move to press the thermoplastic resin foam. As described above, the pressure device may be provided on the two pressure plates. Although the pressurizing device 5 is shown as a device driven by hydraulic pressure, the drive of the pressurizing device 5 is not limited to hydraulic pressure, and any method such as pneumatic pressure or a pressurizing device by mechanical drive may be used. Further, although a heating heater is embedded in the hot plate 10, it is preferable that a pipe in which cooling water is circulated is alternately arranged with the heating heater to be embedded so as to be cooled. ..

In the apparatus shown in FIG. 1, a portion where two pressure plates 2 and 3 facing each other are further formed as a compression chamber 6 so as to cover the surroundings, and the lower end side of the compression chamber 6 is formed. An extruding rod 7 for taking out the reduced volume foam 4 is provided, and a butt 8 for receiving the reduced volume foam is provided at the other end of the extruding rod 7 at the lower end of the compression chamber 6 A hopper 9 for supplying the thermoplastic resin foam 4 to be treated can be connected to the side surface. The compression chamber 6 may be open to the outside, but when the circumference of the compression chamber 6 is covered, a heating device for supplying heating gas such as heating air should be provided to keep the inside of the compression chamber in a heated atmosphere. It is possible to heat the foam inside the compression chamber 6 to further improve the processing speed for volume reduction. Further, a heat insulating material 15 is provided on the back surface side (opposite surface of the pressure plate) of the heat plate 10, and a partition 12 is provided on the hopper 9 side of the moving pressure plate 2, and the partition 12 of the moving pressure plate 2 is provided. The hopper 9 and the compression chamber 6 are opened and closed by moving along with the movement.

What is important in the thermoplastic resin foam volume reducing device 1 of the present invention is that the pressure plates 2 and 3 are provided with a heating device, and the thermoplastic resin foam 4 is pressurized by the heated pressure plate. It is formed so as to compress. The moving pressure plate 2 and the fixed pressure plate 3 may be of any material shape as long as they are capable of heating and compressing a thermoplastic resin, but usually a metal plate such as aluminum, iron or stainless steel is used. A plate having a circular shape or a square shape is used.

FIG. 2 is a cross-sectional view showing another example of the pressure plate used in the volume reducing device of the present invention. For example, as shown in FIG. 2, the moving pressure plate may be provided with a groove 11 on the surface of the fixed pressure plate 3 near the center of the pressure plate for discharging the molten thermoplastic resin foam to the outside. Further, as shown in FIG. 2, the pressure plate may be formed of the mold 31 (or 21) and the support plate 32 (or 22), and the groove 31 may be provided in the mold 31. Further, the surface of the fixed pressure plate 3 is formed so as to be inclined toward the groove 11, and the shape of the mold 21 of the moving pressure plate 2 is formed so as to correspond to the shape of the mold 31 of the fixed pressure plate 3. It is also possible to form the volume-reduced thermoplastic resin foam in a molten resin state so as to be discharged to the outside through the groove 11.

The surfaces of the moving pressure plate 2 and the fixed pressure plate 3 (the side in contact with the foam 4) are covered with a material having a high releasability with respect to the foam 4 such as fluorine resin. It is preferable to leave it. By coating the surface of the pressure plate in this manner, the resin can be easily peeled from the pressure plate. Further, a cooling device may be provided on the pressure plate, which facilitates cooling of the pressure plate and allows the volume-reduced resin to be immediately separated from the pressure plate and discharged to the outside. It is possible to shorten the processing time and improve the processing speed.

In the device of the present invention, the heating device is preferably provided with a temperature adjusting device so that the temperature of the pressure plate can be appropriately selected according to the type of resin of the thermoplastic resin foam to be treated. The temperature of the compression platen is preferably in the range above the melting temperature of the thermoplastic resin and below the decomposition temperature. For example, 100-300 ° C, preferably 130-250 ° C for styrene resin, and polyethylene resin for polyethylene resin. It is suitable to carry out the treatment at 100 to 300 ° C., preferably 130 to 250 ° C., and for polypropylene resin, 150 to 350 ° C., preferably 170 to 300 ° C. Further, the thermoplastic resin foam 4 to be treated by the device of the present invention is not particularly limited and may be of any type and shape, but especially foam such as a tray for food of polystyrene, polyethylene or polypropylene resin foam. With a relatively low foaming ratio of 20 times or less, it is possible to perform particularly good treatment on foams having a shape that easily overlaps.

FIG. 3 is a cross-sectional view showing another example of the volume reducing device for thermoplastic resin foam of the present invention. The device of the present invention may be a device (horizontal device) configured to horizontally move the moving pressure plate 2 as shown in FIG. 3 to horizontally pressurize and compress the foam. In the horizontal type volume reduction device shown in FIG. 3, two pressure plates, a moving pressure plate 2 and a fixed pressure plate 3, are provided in the compression chamber 6, and a heating plate 10 is provided on the pressure plate. Is provided with a pressurizing device 5, and a hopper 9 is provided above the compression chamber 6, and a partition 12 is formed so as to move along with the movement of the moving pressure plate 2 to partition the hopper 9 and the compression chamber 6.

The volume reducing device 1 shown in FIG. 3 is a device (vertical device) in which the pressure plate is vertically slid vertically to compress the foam by vertically pressing it. On the other hand, the sliding direction of the moving pressure plate 3 changes from the vertical direction to the horizontal direction. The effect of compression by heating and pressurization of the pressure plate of the horizontal type device has the same function as that of the device shown in Fig. 1, but the supply of the thermoplastic resin foam and the removal (discharge) of the volume-reduced foam That is different. In the case of the horizontal type device, as shown in FIG. 3, the thermoplastic resin foam 3 is directly supplied from the hopper 9 provided on the upper part of the compression chamber 6, and the extrusion rod 7 on the upper part of the compression chamber 6 is used. The discharge port 14 provided on the lower side of the compression chamber 6 discharges it to the butt 8.

An example of actually reducing the volume of a thermoplastic resin foam using the volume reducing device of the present invention shown in FIG. 1 will be described with a food tray made of expanded polystyrene having an expansion ratio of 13 times as an example. explain. First, the foamed body 4 collected from the top of the hopper 9 is put in, and the pressure plates are heated to about 170 to 180 ° C. with the upper and lower pressure plates 2 and 3 in contact with each other (to increase heating efficiency). After that, the moving pressure plate 2 is raised to a predetermined position, the hopper 9 and the partition 12 of the compression chamber 6 are opened, the foam 4 is introduced into the compression chamber 6, and the pressure plate 2 is placed between the two pressure plates 2, 3. Place it. Next, the moving pressure plate 2 is moved at a predetermined speed to pressurize and compress the foam 4 while heating (when the pressure is low, air bubbles inside the foam escape and the foam completely melts). The hydraulic pressure rises), and the moving pressure plate 2 is stopped at a predetermined position. Finally, the extruded rod 7 is used to extrude the molten resin adhering to the fixed pressure plate 3 to the external vat 8 to obtain a volume-reduced thermoplastic resin foam, and the processing is completed.

When the foam is put into the device 1 of the present invention, as shown in FIG. 3, the foam 4 is preliminarily filled in a polyethylene bag 13 of a size to be put in the compression chamber, and the bag is packed together with the bag. The foam may be charged from the hopper 9 and placed inside the compression chamber 6 and pressurized by a pressure plate to reduce the volume.

The volume-reducing device of the present invention is not particularly limited in size, but if it is configured as a small-sized and low-priced product that can handle food packaging trays, it can be made of recovered thermoplastic resin foam. It is optimally used as a device for volume reduction by installing it in a supermarket etc. in order to reduce the transportation cost of trays.

[0017]

[Effect of the device]

 As described above, the volume reduction device for thermoplastic resin foams of the present invention adopts the structure of pressurizing while heating by the two pressure plates facing each other equipped with the heating device. In comparison with a device that melts using an extruder or extruder, the foam is pressed against the heated pressure plate and comes into contact with it, so that the foam melts efficiently and the unmelted foam is pressed by the pressure plate. Since it comes into contact with and melts, it has the effect of reducing the volume of the thermoplastic resin foam in a short time. In particular, the device of the present invention does not require a pretreatment device such as crushing even for foams having low foaming efficiency such as trays and having a shape that easily overlaps each other and has poor thermal efficiency during heating, and Processing can be performed quickly. In addition, since the device of the present invention mounts the foam between the two pressure plates facing each other, the distance between the pressure plates can be arbitrarily adjusted, so that it can be widely applied to the size and shape of the foam. Yes, there is no need to pre-cut the foam to size. In addition, the compression of the foam is low because the heated pressure plate reduces mutual voids between the foams and the successive foams come into contact with each other. Since it does not need to be used, a small-scale pressurizing device can be used to obtain a lightweight and inexpensive device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a volume reducing device for a thermoplastic resin foam according to the present invention.

FIG. 2 is a sectional view showing another example of a pressure plate.

FIG. 3 is a cross-sectional view showing another example of the device for reducing the volume of a thermoplastic resin foam according to the present invention.

[Explanation of symbols]

 1 Volume Reduction Device for Thermoplastic Resin Foam 2 Moving Pressure Plate 3 Fixed Pressure Plate 4 Thermoplastic Resin Foam 5 Pressurizing Device 10 Hot Plate 11 Groove

Claims (2)

[Scope of utility model registration request] 1. A device for compressing a thermoplastic resin foam placed between two pressure plates facing each other to reduce the volume of the thermoplastic resin foam, which is for heating the pressure plate. A volume reducing apparatus for a thermoplastic resin foam, comprising a heating device, and at least one of the pressure plates comprises a pressure device for pressurizing and compressing the thermoplastic resin foam while heating. 2. The volume reduction of the thermoplastic resin foam according to claim 1, wherein a groove or a recess for discharging the melted thermoplastic resin foam to the outside is formed on the surface of at least one of the pressure plates. apparatus.