Manufacturing method for recycled bead foam

Abstract

To provide a manufacturing method of a regenerated bead foam enabling reuse of a crushed, deformed, and recovered bead foam as a bead foam as it is other than making a material for a foamed polystyrene molding, and the regenerated bead foam.SOLUTION: A manufacturing apparatus of a bead foam in which raw material beads of a first weight is heated in a drum 2 and heating is stopped by detecting that an aggregate of expanding bead foam has reached a predetermined volume by using a photoelectric sensor 19 to obtain, e.g., a bead foam with a forming rate of 40% is used, and in the same manner, an aggregate of recovered bead foams including bead foams deformed by an external pressure which is a first weight is supplied to the drum 2, then re-expanded by heating, and heating is stopped by detecting that an aggregate of re-expanding bead foam has reached a predetermined volume by using a photoelectric sensor 19 to obtain a regenerated bead foam having a foaming rate of 40%.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a recycled bead foam and a recycled bead foam and the like.

Background Art

[0002] A bead foam is a spherical body made of a foamed plastic. As the foamed plastic, for example, styrene foam polymerized with a styrene monomer resin or a polystyrene resin as a main raw material is used. In some cases, a styrene foam molded body is manufactured using the bead foam as a further raw material. In recent years, it has been increasingly used as the content of a cushion body called a bead cushion, which is formed by filling bead foams into an outer skin that is three-dimensionally sewn in a bag shape. Patent Document 1 is shown as an example of the cushion body. For example, as shown in FIG. 3 of Patent Document 1, a large number of small beads 9 as bead foams made of foamed polystyrene are filled in an inner bag 4 inside an outer skin 2 of a cushion body 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a cushion body 1 filled with beads 9 (bead foams) as in Patent Document 1, when a person sits or leans on it and continues to use it over time, it is pushed or crushed, and gradually deformed as shown in FIG. 3, becoming smaller and shrinking, and the bead foam no longer remains in its original beautiful spherical shape. Although such a cushion body with deformed bead foams can continue to be used by replenishing the bead foams, if there are many crushed bead foams in the whole, it will eventually have to be discarded. Some foam bead suppliers offer a service to collect these crushed and deformed foam beads. These manufacturers use the collected foam beads as fuel or as material for recycled polystyrene foam molded products. However, in addition to using the recovered, crushed, and deformed foam beads as material for expanded polystyrene molded products, other methods of reusing the foam beads as they are are being explored. [Means for solving the problem]

[0005] As a first means to achieve the above objective, a bead foam manufacturing apparatus is used, which comprises a heating means for heating and foaming a predetermined first weight of raw beads, a container for containing the bead foam foamed by the heating means, and a detection means for detecting when the aggregate of the bead foam has reached a predetermined amount in the container, and which terminates the heating treatment of the bead foam based on a detection signal from the detection means to obtain bead foam with a predetermined foaming rate. The aggregate of bead foam, including the bead foam deformed by external pressure, is weighed out to a predetermined second weight and placed into the container, the detection means detects when the aggregate of bead foam has reached a predetermined amount, and the heating treatment of the bead foam is terminated based on a detection signal from the detection means to obtain recycled bead foam with a predetermined foaming rate based on the ratio of the predetermined first weight to the predetermined second weight. By this method, deformed bead foam can be re-expanded into a spherical shape, and recycled bead foam with a known expansion rate can be obtained. The inventors confirmed that even deformed bead foam can be recycled to produce bead foam equivalent to that of the original bead foam by following the procedure for heating the raw beads. However, it was unclear how to determine the foaming ratio of the recycled bead foam. By using this method, however, it is possible to obtain recycled bead foam with a clearly defined foaming ratio based on weight and the corresponding foaming ratio for that weight.

[0006] The bead foam in this invention is manufactured by the bead method. The "raw material beads" used in the bead method are preferably prepared by impregnating foamy particles polymerized from, for example, a styrene monomer-based resin or a polystyrene-based resin as the main raw material with at least a foaming agent. The raw material beads should ideally be around 0.05 to 2 mm in size. Unused foamed beads will vary in size after foaming, even if the foaming rate is the same, due to differences in the raw material bead size. On the other hand, foamed beads deformed by external pressure will have parts that do not reflect the original foaming rate because they have been crushed. The phrase "the assembly of bead foams, including the bead foams deformed by external pressure" means that it may include some bead foams that have not been deformed. Of course, it is also possible that all of them are deformed by external pressure. The predetermined first weight and the predetermined second weight may be the same or different. If they are different, for example, if the manufacturing apparatus for bead foam produces a foaming rate of 50 times per kg of raw beads, then using half the weight of A kg will yield recycled bead foam with a foaming rate of approximately 50 times × 2 = 100 times, although this will depend on other conditions as well. The "heating method" could be, for example, heating by steam, but other optimal heating methods can be selected depending on the material of the bead foam. Direct heat may be applied, or heating by electromagnetic waves such as microwaves may be used. The "detection means" only needs to be able to detect the overall volume of the bead foam, and suitable examples include photoelectric sensors, proximity switches, and limit switches. Photoelectric sensors are particularly good because they are less affected by heat. "A predetermined amount" refers to the amount by which the volume of the bead foam aggregate, that is, the entire collection of bead foam contained in a sealed space, expands due to heating, causing the whole to grow larger.

[0007] As a second measure, the predetermined first weight and the predetermined second weight were made to be the same weight. This makes it possible to obtain recycled bead foam with the same foaming rate as unused bead foam produced by the manufacturing equipment. Furthermore, as a third measure, the heat treatment of the predetermined weight of raw material beads by the heating means is carried out inside the container. This is because performing the heat treatment of the raw beads in the same container allows for rapid foaming and the acquisition of raw beads with a precise foaming rate. Furthermore, as a fourth measure, the detection means is configured to detect the ends of the aggregate of foamed beads that foams and expands within the container. By detecting in this way, the detection means can reliably detect aggregates of foamed beads with the same foaming rate. Furthermore, as a fifth measure, the intended foaming rate of the deformed bead foam was made to be the same as the foaming rate of the bead foam before deformation. This makes it possible to obtain recycled bead foam with an expansion rate equivalent to that of unused bead foam produced by the manufacturing apparatus. To achieve an equivalent expansion rate, it is preferable to make the predetermined first weight and the predetermined second weight the same, as described above. The same weight is the weight that targets an equivalent expansion rate. An equivalent expansion rate means an expansion rate that is the same or can be considered the same. As a sixth measure, the end of the heat treatment of the bead foam is determined by discharging the bead foam with a predetermined foaming ratio from the container. This allows the foamed beads to be discharged from the container after heating is complete, quickly lowering the temperature and enabling the production of foamed beads with the precisely planned expansion rate. [Effects of the Invention]

[0008] According to the present invention, by this method, deformed bead foam can be re-expanded into a spherical shape and recycled bead foam with a known expansion rate can be obtained. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram illustrating the manufacturing apparatus for the bead foam used in an embodiment of the present invention. [Figure 2]An illustrative diagram explaining the internal configuration of the weighing device in a manufacturing apparatus for the same bead foam. [Figure 3] An illustrative diagram showing the bead foam material before and after deformation. [Modes for carrying out the invention]

[0010] The method for producing recycled bead foam and the recycled bead foam according to embodiments of the present invention will be described below with reference to the drawings. First, an overview of the bead foam manufacturing apparatus 1 (hereinafter referred to as "manufacturing apparatus 1") of this embodiment will be described based on Figure 1. Components not directly related to the present invention will be omitted. As shown in Figure 1, the manufacturing apparatus 1 is equipped with a drum 2 as a container. A weighing device 3 is installed at the upper side of the drum 2 to introduce a fixed amount of foaming material supplied from upstream into the drum 2. The weighing device 3 is equipped with a plurality of hoppers and sensors etc. placed between the hoppers, and is configured to supply a predetermined weight of foaming material into the drum 2 at a predetermined timing. Specifically, the weighing device 3 is configured as shown in Figure 2, for example. The weighing device 3 is equipped with first hoppers 4A to fourth hoppers 4D in order from top to bottom. A limit switch 5 is installed between the first hopper 4A and the second hopper 4B. A load cell 6 is installed between the second hopper 4B and the third hopper 4C. A rotary actuator 7 is installed at the lower end of the third hopper 4C. A cylinder device 8 for releasing the foaming material downwards is installed inside the fourth hopper 4D. The second hopper 4B has multiple nozzles 9 that allow foaming material to flow down into the third hopper 4C, and each nozzle 9 is equipped with a shutter device 10 whose passage is opened and closed based on the value detected by the load cell 6. The behavior of the foaming material introduced into the weighing device 3 until it reaches the drum 2 will be explained. The foaming material introduced from the first hopper 4A is supplied into the second hopper 4B. When the foaming material is detected by the limit switch 5, the supply stops, and when the detection stops, the supply resumes based on the detection signal. In other words, it is controlled so that a constant amount of foaming material is always accumulated in the second hopper 4B. When the foaming material is supplied from the second hopper 4B to the third hopper 4C, a predetermined weight is weighed by the load cell 6, and the predetermined weight of foaming material is stored in the third hopper 4C. In this embodiment, the predetermined weight is set to the weight Pkg that targets a foaming rate of 40% in this manufacturing apparatus 1. When the previously predetermined weight of foaming material is supplied from the fourth hopper 4D into the drum 2, the rotary actuator 7 is activated, and the predetermined weight in the third hopper 4C is supplied to the fourth hopper 4D, which has become empty of foaming material, and enters a standby state. A predetermined weight is again weighed into the third hopper 4C, and the predetermined weight of foaming material is stored there. Furthermore, the predetermined weight Pkg described above can be changed to any weight by the operator adjusting a control panel (not shown) that controls the driving timing of the shutter device 10 in relation to the detected value of the load cell 6.

[0011] A switching valve 11 is located at the top of the weighing device 3 to switch the foaming material into the weighing device 3. The switching valve 11 is connected to a pipeline 12 for supplying raw material beads as foaming material and a pipeline 13 for supplying used recovered bead foam as foaming material. A supply blower 14 for dispensing the foaming material is connected to pipelines 12 and 13, respectively. A propeller 15 for stirring is installed inside the drum 2. The pivot shaft 16 of the propeller 15 is connected to a motor 17 for stirring the foaming material at the upper center of the drum 2. A steam duct 18 is connected to the upper side of the drum 2. The steam duct 18 serves as a supply port for steam supplied from a steam device (not shown) and as an exhaust port for steam supplied into the drum 2. A reflective photoelectric sensor 19 is installed on the wall of the drum 2 below the steam duct 18 as a detection means. The photoelectric sensor 19 detects the upper end position of the bead foam inside the drum 2. On the lower side near the side of the drum 2, a discharge duct 20 for discharging the bead foam with the foaming completed is formed. At the position of the opening 20a near the drum 2 of the discharge duct 20, a door 22 formed at the tip of the piston 21a of the cylinder device 21 is arranged, and the opening 20a is opened and closed by the forward and backward movement of the piston 21a. A bead storage case 23 for receiving the bead foam is arranged at a position below the discharge duct 20. A pipeline 24 is connected near the bottom of the bead storage case 23, and the bead foam is stored in a downstream silo not shown by a discharge blower 25 arranged adjacent to the pipeline 24. A drain 26 is formed at the bottom of the drum 2. A discharge pipe not shown is connected to the drain 26.

[0012] Such a manufacturing apparatus 1 is operated by sequence control by, for example, a controller not shown. An example of specific control will be described. (1) When the previous bead foam is discharged from the discharge duct 20 with the door 22 opened, the air in the drum 2 is exhausted from the steam duct 18 with the door 22 opened, and the temperature in the drum 2 once drops to a temperature below the reference. Then, the door 22 is closed again, and a foaming raw material of a predetermined weight Pkg is put into the drum 2 from the metering device 3. (2) Heating steam is introduced into the airtight drum 2 from the steam duct 18, and the motor 17 is driven to stir the inside by the propeller 15. That is, the foaming raw material is heated while being stirred. (3) As the foaming raw material foams according to the heating, the overall volume gradually increases, and the photoelectric sensor 19 detects the upper end of the bead foam derived from the foaming raw material. This stage is the planned foaming rate (here 40%). Simultaneously with the detection, the bead foam is discharged from the discharge duct 20 with the door 22 opened, and (1) to (3) are repeated. The bead foam discharged into the bead storage case 23 is stored in a silo not shown via the pipeline 24.

[0013] Next, the correspondence when using raw material beads as the foaming raw material and when using the used recovered bead foam will be described. When using raw material beads and when using recycled used beads foam, the one with a larger throughput is used as the main foaming raw material, and the one with a smaller throughput is used as the sub-foaming raw material. Here, as an example, when using raw material beads, it is used as the main foaming raw material. The recycled used beads foam was originally set to a foaming ratio of 40% in an unused state. For example, the bead foam produced under the same conditions in the same manufacturing apparatus 1 has been used over time, and part or almost all of it has deformed as shown in FIG. 3. The operator mainly manufactures recycled bead foam from the sub-foaming raw material according to the above control process with the main foaming raw material. When switching to the sub-foaming raw material, an operation panel (not shown) is operated to temporarily stop the above process of the manufacturing apparatus 1, and then an operation is performed to switch the port of the switching valve 11 from the pipeline 12 to the pipeline 13 so that the sub-foaming raw material is introduced into the metering device 3. At this time, since the predetermined weight of the sub-foaming raw material measured by the metering device 3 is the same as that of the main foaming raw material at the weight Pkg, the re-foamed sub-foaming raw material (recycled bead foam) will be controlled to the same 40% foaming ratio as the main foaming raw material even if it is re-foamed and detected by the photoelectric sensor 19.

[0014] In the manufacturing method of the recycled bead foam configured as described above, the following effects are achieved. (1) The raw material beads and the recycled used beads foam are completely different in size, and the recycled used beads foam has a shape in which many of the spheres are deformed. However, since the recycled bead foam is obtained by detecting an aggregate of bead foams that have expanded to a certain position by the photoelectric sensor 19 on the basis of weight as described above, the same foaming ratio as that of the unused bead foam using the raw material beads can be achieved. (2) Since the same manufacturing apparatus 1 as the manufacturing apparatus 1 for manufacturing the unused bead foam can be used, there is no need to prepare another apparatus for recycling the recycled used beads foam. (3) By simply switching the port of the switching valve 11 from pipeline 12 to pipeline 13, the main foaming material can be changed to a sub-foaming material (and vice versa), making it easy to obtain bead foams with the same foaming rate but different materials. (4) By changing the weight of the sub-foaming material relative to the main foaming material, any two types of bead foams with different foaming rates can be easily obtained.

[0015] The above embodiments are merely described as specific examples illustrating the principles and concepts of the present invention. In other words, the present invention is not limited to the above embodiments. The present invention can also be embodied in modified forms, for example, as follows. The configuration of the manufacturing apparatus 1 in the above embodiment is just one example. Therefore, other shapes of manufacturing apparatus may be used. For example, the heating means is not limited to steam. The detection means is not limited to the photoelectric sensor 19. In the above embodiment, the switching between the main foaming raw material and the sub-foaming raw material was performed by switching the port of the switching valve 11. However, even without providing such a switching valve 11, the raw material pipeline to the weighing device 3 may be switched by an operator each time. Alternatively, even when switching is required, the switching of the raw material pipeline leading to the weighing device 3 may be performed manually without providing a switching valve 11. In the above embodiment, the weights of the main foaming material and the sub-foaming material were kept the same to achieve the same foaming rate. However, by changing the weights, different foaming rates may be actively achieved. The present invention is not limited to the configuration described in the embodiments above. The components of each embodiment and modification described above may be arbitrarily selected and combined. Furthermore, any component of each embodiment and modification may be arbitrarily combined with any component described in the means for solving the invention or any component that embodies any component described in the means for solving the invention. We intend to obtain rights for these as well by amending this application or changing it to a patent application. [Explanation of Symbols]

[0016] 1...A manufacturing apparatus for bead foam, 2...A drum as a container, 19...A photoelectric sensor as a detection means.

Claims

1. A bead foam manufacturing apparatus is used, comprising: a heating means for heating and foaming a predetermined weight of raw beads; a container for containing the bead foam foamed by the heating means; and a detection means for detecting when the aggregate of bead foam has reached a predetermined volume due to foaming within the container, wherein the heating process of the bead foam is terminated based on a detection signal from the detection means to obtain bead foam with a predetermined foaming rate. A method for producing recycled bead foam, comprising: placing a predetermined weight of an aggregate of bead foam (hereinafter referred to as "recovered foaming raw material") including the bead foam deformed by external pressure into the container; detecting when the re-foamed recycled bead foam, which has been re-foamed by heating with the heating means, has reached a predetermined volume using the detection means; and terminating the heating treatment of the recycled bead foam based on the detection signal from the detection means to obtain recycled bead foam with a predetermined foaming ratio corresponding to its weight.

2. The method for producing recycled bead foam according to Claim 1, characterized in that the raw material beads and the recovered foaming material are of the same weight when foaming.

3. The method for producing recycled bead foam according to Claim 1, characterized in that the raw material beads and the recovered foaming material used for foaming are of different weights.

4. The method for producing recycled bead foam according to any one of 1 to 3, characterized in that the heat treatment of the predetermined weight of the raw beads by the heating means is performed inside the container.

5. The method for producing recycled bead foam according to claim 4, characterized in that the detection means detects the end of the aggregate of the bead foam or recycled bead foam that foams and expands in the container.

6. The method for producing recycled bead foam according to any one of claims 1 to 3, characterized in that the foaming rate of the recycled bead foam intended for the recovered foaming raw material when using the bead foam production apparatus is equivalent to the foaming rate of the bead foam of the raw beads.

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