Resin processing apparatus, method for manufacturing resin pellets, and method for processing resin materials

Abstract

To efficiently process a resin material such as waste plastic.SOLUTION: A resin processing apparatus 1 includes: an extruder 11 to which a resin material 51 is supplied; and an extruder 21 to which the extruder 11 is connected, and a residual resin discharged from the extruder 11 is supplied. Regarding a temperature of a cylinder 12 of the extruder 1, a downstream side of a kneading part 61 is set higher than a thermal decomposition temperature of the resin material 51. Regarding a temperature of the cylinder 22 of the extruder 21, a downstream side of a position at which the residual resin is supplied is set lower than the thermal decomposition temperature of the residual resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resin treatment apparatus, a method for manufacturing resin pellets, and a method for treating resin materials.

Background Art

[0002] Japanese Patent Application Laid-Open No. 11-106758 (Patent Document 1) and Japanese Patent Application Laid-Open No. 11-50072 (Patent Document 2) describe technologies related to the treatment of waste plastics.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, recycling by treating resin materials such as waste plastics has been promoted, and it is desired to efficiently treat resin materials.

[0005] As a method for treating resin materials such as waste plastics, it is conceivable to thermally decompose the resin material to generate monomers and recover the generated monomers. An extruder can be used for the thermal decomposition of the resin material. For example, the resin material to be treated is supplied into the cylinder of the extruder, and while melting the resin material by conveying it forward by the screw in the cylinder, the molten resin is thermally decomposed in the cylinder of the extruder to generate monomer gas. The monomer gas generated in the cylinder of the extruder is sent from the gas discharge part of the cylinder to a heat exchanger and liquefied, and the liquefied monomer can be recovered.

[0006] In this case, the residue left after processing the resin material is pushed out from the tip of the extruder cylinder. If the resin material being processed contains fillers, those fillers are also contained in the residue pushed out from the tip of the extruder cylinder. To deal with the residue pushed out from the tip of the cylinder, it is conceivable to connect a storage container to the tip of the extruder cylinder and store the residue pushed out from the tip of the extruder cylinder in this storage container. However, once the storage container is full, it becomes impossible to process the resin material using the extruder any further. Therefore, it is necessary to remove the residue stored in the storage container connected to the tip of the cylinder before it becomes full and empty the storage container. During this operation, the extruder must be stopped, which reduces the operating efficiency of the extruder and the processing efficiency of resin materials such as waste plastics. In addition, this operation may increase the processing cost of resin materials such as waste plastics. Furthermore, when removing residue from storage containers, it is desirable to prevent the monogas inside the containers from diffusing into the surroundings. Therefore, the process of removing residue from storage containers is difficult and burdensome.

[0007] Other challenges and novel features will become apparent from the description and accompanying drawings in this specification. [Means for solving the problem]

[0008] According to one embodiment, the resin processing apparatus includes a first extruder to which a first resin material is supplied, and a second extruder to which the first extruder is connected and to which the residual resin discharged from the first extruder is supplied. The temperature of the cylinder of the first extruder is set to be higher than the thermal decomposition temperature of the first resin material downstream of the first kneading section. The temperature of the cylinder of the second extruder is set to be lower than the thermal decomposition temperature of the residual resin downstream of the position to which the residual resin is supplied. [Effects of the Invention]

[0009] According to one embodiment, resin materials such as waste plastics can be processed efficiently. [Brief explanation of the drawing]

[0010] [Figure 1] This is an explanatory diagram showing a schematic configuration of a resin processing apparatus in one embodiment. [Figure 2] This is an explanatory diagram showing an example configuration of a pellet manufacturing system using a resin processing apparatus according to one embodiment. [Figure 3] This is an explanatory diagram showing the configuration of the waste plastic processing system considered by the inventor. [Figure 4] This is an explanatory diagram showing a resin processing apparatus of the first modified example. [Figure 5] This is an explanatory diagram showing a resin processing apparatus of the second modified example. [Figure 6] This is an explanatory diagram showing a resin processing apparatus of the third modified example. [Figure 7] This is an explanatory diagram showing a resin processing apparatus of the third modified example. [Figure 8] This is an explanatory diagram showing a resin processing apparatus of the fourth modified example. [Figure 9] This is an explanatory diagram showing a resin processing apparatus of the fifth modified example. [Figure 10] This is an explanatory diagram showing a resin processing apparatus of the sixth modified example. [Modes for carrying out the invention]

[0011] The embodiments will be described in detail below with reference to the drawings. In all the drawings used to describe the embodiments, the same reference numerals are used for members having the same function, and repeated descriptions of them will be omitted. In addition, in the following embodiments, descriptions of the same or similar parts will not be repeated unless it is particularly necessary.

[0012] <About the configuration of the resin processing equipment> The overall configuration of the resin processing apparatus 1 in this embodiment will be described with reference to Figure 1. Figure 1 is an explanatory diagram (side view) showing the schematic configuration of the resin processing apparatus 1 in this embodiment.

[0013] The resin processing apparatus 1 shown in Figure 1 includes an extruder 11 and an extruder 21, and has a configuration in which these extruders 11 and 21 are connected.

[0014] The extruder 11 comprises a cylinder (barrel) 12, a screw 13 rotatably positioned inside the cylinder 12, a rotary drive mechanism 14 for rotating the screw 13 inside the cylinder 12, a hopper (material input section, material supply section) 15 located upstream (rear end) of the cylinder 12, and a control unit 18 for controlling the operation of the extruder 11. The extruder 21 comprises a cylinder (barrel) 22, a screw 23 rotatably positioned inside the cylinder 22, a rotary drive mechanism 24 for rotating the screw 23 inside the cylinder 22, a hopper (material input section, material supply section) 25 located upstream (rear end) of the cylinder 22, a die (mold) 26 attached to the downstream end of the cylinder 22, and a control unit 28 for controlling the operation of the extruder 21. The cylinder 12 consists of a plurality of cylinder blocks, which are arranged and connected in a direction from upstream to downstream. The cylinder 22 consists of multiple cylinder blocks, which are arranged and connected in a direction from upstream to downstream. No molding die (corresponding to die 26) is attached to the tip of the cylinder 12. Furthermore, the resin processing apparatus 1 shown in Figure 1 has a connecting part 31 that connects the cylinder 12 of the extruder 11 and the cylinder 22 of the extruder 21, and supplies the material extruded from the cylinder 12 of the extruder 11 to the cylinder 22 of the extruder 21.

[0015] The hopper 15 is connected to the upper surface of the cylinder 12, and resin material 51 (such as waste plastic) for processing can be supplied into the cylinder 12 through the hopper 15. As waste plastic, there are plastic products discarded after use in ordinary households, etc., and plastic waste (parts that cannot be used as products) generated during the process of manufacturing plastic products.

[0016] The cylinder 12 has a temperature adjustment mechanism (temperature adjustment means), not shown, such as a heater. By the control unit 18 controlling the temperature adjustment mechanism of the cylinder 12, the temperature of the cylinder 12 can be controlled. The hopper 25 is connected to the upper surface of the cylinder 22, and resin material 52 can be supplied into the cylinder 22 through the hopper 25. The cylinder 22 has a temperature adjustment mechanism (temperature adjustment means), not shown, such as a heater. By the control unit 28 controlling the temperature adjustment mechanism of the cylinder 22, the temperature of the cylinder 22 can be controlled.

[0017] In addition, when referring to the "downstream side" and "upstream side" with respect to the cylinder 12 and the screw 13, the "downstream side" means the downstream side of the flow of the material (resin) in the cylinder 12, and the "upstream side" means the upstream side of the flow of the material (resin) in the cylinder 12. For this reason, in the cylinder 12 and the screw 13, the side closer to the tip of the cylinder 12 is the downstream side, and the side farther from the tip of the cylinder 12 (that is, the side closer to the hopper 15) is the upstream side. The tip of the cylinder 12 corresponds to the end of the cylinder 12 where the resin is extruded, and thus corresponds to the end connected to the connection part 31.

[0018] Furthermore, when referring to the cylinder 22 and screw 23 as "downstream" and "upstream," the "downstream" refers to the downstream side of the material (resin) flow within the cylinder 22, and the "upstream" refers to the upstream side of the material (resin) flow within the cylinder 22. Therefore, in the cylinder 22 and screw 23, the side closer to the tip of the cylinder 22 is the downstream side, and the side further from the tip of the cylinder 22 (i.e., the side closer to the hopper 25) is the upstream side. The tip of the cylinder 22 corresponds to the end of the cylinder 22 from which the resin is extruded, and therefore corresponds to the end to which the die 26 is connected.

[0019] Two screws 13 are rotatably inserted and housed inside cylinder 12. Similarly, two screws 23 are rotatably inserted and housed inside cylinder 22. Therefore, each of the extruders 11 and 21 can be considered a twin-screw extruder. Inside cylinder 12, the two screws 13 are arranged to mesh with each other and rotate, and inside cylinder 22, the two screws 23 are arranged to mesh with each other and rotate. Inside cylinder 12, the resin material is conveyed and kneaded by the rotating screws 13. Similarly, inside cylinder 22, the resin material is conveyed and kneaded by the rotating screws 23.

[0020] In this embodiment, the case where there are two screws 13 in the cylinder 12 is described, but in other forms, the number of screws 13 in the cylinder 12 can be one. Also, in this embodiment, the case where there are two screws 23 in the cylinder 22 is described, but in other forms, the number of screws 23 in the cylinder 22 can be one.

[0021] The cylinder 12 has an opening at the location where the hopper 15 is connected, and the hopper 15 is connected so as to communicate with this opening. As a result, the resin material 51 that is put into the hopper 15 is supplied into the cylinder 12 from the opening of the cylinder 12.

[0022] The cylinder 12 has a gas discharge section (gas exhaust port, gas recovery mechanism) 17 that discharges the gas generated inside the cylinder 12 to the outside of the cylinder 12. In the cylinder 12, the gas discharge section 17 is located downstream of the connection point of the hopper 15. The gas generated inside the cylinder 12 is discharged (exhausted) from the gas discharge section 17 to the outside of the cylinder 12 and sent to the heat exchanger 44, which will be described later, through the gas piping 46, which will be described later.

[0023] The cylinder 22 has an opening (hopper opening) at the position where the hopper 25 is connected, and the hopper 25 is connected so as to communicate with this hopper opening. As a result, the resin material 52 that is put into the hopper 25 is supplied into the cylinder 22 from the hopper opening of the cylinder 22.

[0024] The extruder 11 is connected to the extruder 21 so that the residual resin discharged from the extruder 11 is supplied to the extruder 21. Specifically, the cylinder 12 of the extruder 11 is connected to the cylinder 22 of the extruder 21 via a connecting part 31. The tip of the cylinder 12 is connected to the connecting part 31, and the opening at the tip of the cylinder 12 communicates with the connecting part 31. The connecting part 31 has a passage path (cavity) through which the material (residual resin) discharged from the tip of the cylinder 12 can pass. The cylinder 22 has an opening (opening for the connecting part 31) at the position where the connecting part 31 is connected, and the connecting part 31 is connected so as to communicate with this opening. As a result, the material (residual resin) discharged from the extruder 11, i.e., the material (residual resin) discharged from the tip of the cylinder 12, passes through the connecting part 31 and is supplied into the cylinder 22 through the opening (opening for the connecting part 31) of the cylinder 22. The connection part 31 can function as a path for the material (residual resin) discharged from the tip of the cylinder 12 to reach (be supplied to) the cylinder 22. In the cylinder 22, the connection position of the connection part 31 is located downstream of the connection position of the hopper 25. Also, in the case of Figure 1, the height position of the cylinder 12 is higher than the height position of the cylinder 22, and the connection part 31 is connected to the upper surface of the cylinder 22. The material (residual resin) pushed out from the tip of the cylinder 12 is supplied into the cylinder 22 from the upper surface of the cylinder 22 through the connection part 31.

[0025] The cylinder 22 of the extruder 21 has a gas discharge section (gas exhaust port, gas recovery mechanism) 27 that discharges the gas that has flowed into the cylinder 22 from the cylinder 12 to the outside of the cylinder 22. In the cylinder 22, the gas discharge section 27 is located downstream of the connection position of the hopper 25 and also downstream of the connection position of the connection section 31. The gas that has flowed into the cylinder 22 from the cylinder 12 through the connection section 31 is discharged (exhausted) from the gas discharge section 27 to the outside of the cylinder 22 and sent to the heat exchanger 44, which will be described later, through the gas piping 46, which will be described later.

[0026] The die 26 can function to shape the resin mixture (molten resin) extruded from the cylinder 22 into a predetermined cross-sectional shape (for example, a string shape) and then discharge it. For this reason, the die 26 is an extrusion die (mold). Since the resin mixture extruded from the tip of the cylinder 22 needs to be shaped into a predetermined shape (in this case, a string shape), a resin molding die 26 is attached to the tip of the cylinder 22. However, since the material extruded from the tip of the cylinder 12 only needs to be supplied into the cylinder 22 via the connection part 31, a resin molding die (mold) is not attached to the tip of the cylinder 12.

[0027] <About the pellet manufacturing system> Figure 2 is an explanatory diagram showing an example configuration of a pellet manufacturing system (resin pellet manufacturing apparatus) 41 as a resin processing system using the resin processing apparatus 1 of this embodiment. The pellet manufacturing system 41 of this embodiment is a resin pellet manufacturing system (manufacturing apparatus), but it can also function as a processing system (processing apparatus) for resin materials such as waste plastics.

[0028] The pellet manufacturing system 41 shown in Figure 2 further includes, in addition to the resin processing apparatus 1 described above, a cooling tank (strand bath) 42, a cutting device 43, a heat exchanger 44, and a recovery container 45.

[0029] Next, the operation of the pellet manufacturing system 41, including the resin processing apparatus 1, will be described with reference to Figures 1 and 2. Note that the extruder 11, which constitutes the resin processing apparatus 1, is controlled by the control unit 18, and the extruder 21, which also constitutes the resin processing apparatus 1, is controlled by the control unit 28. However, the extruder 11 and the extruder 21 can also be controlled by a common control unit.

[0030] Resin material 51 is supplied from hopper 15 into cylinder 12, and resin material 52 is supplied from hopper 25 into cylinder 22.

[0031] The resin material 51 supplied from the hopper 15 into the cylinder 12 contains resin components and can be made from, for example, crushed used resin products, or waste plastics. In addition to resin components, the resin material 51 supplied from the hopper 15 into the cylinder 12 may also contain fillers other than resin components (e.g., inorganic fillers). Examples of fillers include glass fibers, carbon fibers, talc, or calcium carbonate.

[0032] Furthermore, the following will refer to the thermal decomposition temperature T1 of the resin material 51, which corresponds to the temperature at which the resin components contained in the resin material 51 supplied from the hopper 15 into the cylinder 12 undergo thermal decomposition.

[0033] In the extruder 11, the resin material 51 supplied from the hopper 15 into the cylinder 12 is transported forward within the cylinder 12 by the rotation of the screw 13 and plasticized to become molten resin. In Figures 1 and 2, the kneading section (plasticizing section) 61 in the cylinder 12 of the extruder 11 is shown enclosed by a dotted line. The kneading section 61 corresponds to the region in the cylinder 12 where the resin material 51 supplied from the hopper 15 is plasticized to become molten resin, and can be considered a plasticizing section. In the cylinder 12 of the extruder 11, the kneading section 61 is located downstream of the connection point of the hopper 15 and upstream of the gas discharge section 17.

[0034] In the cylinder 12, upstream of the mixing section 61, the resin material 51 in the cylinder 12 is still in a solid state and has not yet melted. However, in the mixing section 61, the resin material 51 is plasticized and becomes molten (molten resin), and downstream of the mixing section 61, the resin material 51 in the cylinder 12 is molten resin. Therefore, arrow 71 in Figure 2 shows the flow of solid resin material 51, and arrow 72 in Figure 2 shows the flow of molten resin material 51 (molten resin). If the resin material 51 supplied from the hopper 15 into the cylinder 12 contains filler, the molten resin in the cylinder 12 will contain filler.

[0035] The temperature of the cylinder 12 of the extruder 11 is set higher than the thermal decomposition temperature T1 of the resin material 51 downstream of the kneading section 61. That is, the temperature of the cylinder 12 downstream of the kneading section 61 is set to a temperature higher than the thermal decomposition temperature T1 of the resin material 51 (for example, 400°C). The temperature of the cylinder 12 of the extruder 11 can be controlled by the control unit 18 controlling the temperature control mechanism of the cylinder 12. Hereinafter, when "set temperature of cylinder 12" refers to "temperature of cylinder 12 downstream of the kneading section 61". The temperature of cylinder 12 upstream of the kneading section 61 can be set to an appropriate temperature as needed, and may be below the thermal decomposition temperature T1 of the resin material 51.

[0036] The resin material 51 supplied from the hopper 15 into the cylinder 12 is plasticized in the mixing section 61 of the cylinder 12 to become molten resin, which is then sent further forward (downstream) within the cylinder 12 by the rotation of the screw 13. Since the set temperature of the cylinder 12 is set higher than the thermal decomposition temperature T1 of the resin material 51, downstream of the mixing section 61, the resin components in the molten resin within the cylinder 12 are heated to a temperature higher than the thermal decomposition temperature T1, causing thermal decomposition and becoming gaseous monomer (hereinafter referred to as "monomer gas"). The monomer gas generated within the cylinder 12 is discharged outside the cylinder 12 from the gas discharge section 17 and sent to the heat exchanger 44 through the gas piping (gas pipeline) 46.

[0037] Of the molten resin in cylinder 12, a portion is thermally decomposed into a monomer gas, which is sent from the gas discharge section 17 through the gas piping 46 to the heat exchanger 44. The remainder (molten resin that was not thermally decomposed) is pushed out from the tip of cylinder 12. In addition, the filler contained in the molten resin inside cylinder 12 is not thermally decomposed. Therefore, the filler contained in the molten resin inside cylinder 12 is pushed out (discharged) from the tip of cylinder 12 together with the molten resin that was not thermally decomposed (not monomerized). The residual resin (resin material including filler), which is the material pushed out from the tip of cylinder 12, is supplied into cylinder 22 through the opening of cylinder 22 (opening for connection section 31) via the connection section 31. Arrow 73 in Figure 2 indicates the flow of residual resin pushed out from the tip of cylinder 12. The residual resin (73) pushed out from the tip of cylinder 12 is supplied to cylinder 22 via the connection section 31.

[0038] Ideally, all of the monogas generated in cylinder 12 should be discharged outside cylinder 12 through gas discharge section 17 and sent to heat exchanger 44 via gas piping 46. However, in reality, some of the monogas generated in cylinder 12 is sent to heat exchanger 44 via gas piping 46 from gas discharge section 17, while the remainder is discharged from the tip of cylinder 12 along with the molten resin and filler that have not been thermally decomposed and flows into connection section 31. Of the monogas that flows from cylinder 12 into connection section 31, some is discharged outside connection section 31 through gas discharge section (gas exhaust port, gas recovery mechanism) 32 provided in connection section 31 and sent to heat exchanger 44 via gas piping 46, while the remainder flows into cylinder 22 from connection section 31 along with the molten resin and filler.

[0039] The resin material 52 supplied from the hopper 25 into the cylinder 22 is a resin material (raw material) for manufacturing resin pellets. Therefore, any resin material suitable for manufacturing resin pellets can be used as the resin material 52 supplied from the hopper 25 into the cylinder 22. The resin components contained in this resin material 52 may be the same type of resin as the resin components contained in the resin material 51 supplied from the hopper 15 into the cylinder 12. In addition, the resin material 52 may further contain fillers suitable for manufacturing resin pellets in addition to the resin components.

[0040] Furthermore, the following will refer to the thermal decomposition temperature T2 of the resin material 52, which corresponds to the temperature at which the resin components contained in the resin material 52 supplied from the hopper 25 into the cylinder 22 undergo thermal decomposition.

[0041] In the extruder 21, the resin material 52 supplied from the hopper 25 into the cylinder 22 is plasticized and becomes molten resin as it is moved forward by the rotation of the screw 23 within the cylinder 22. In Figures 1 and 2, the kneading section (plasticizing section) 62 in the cylinder 22 of the extruder 21 is shown enclosed by a dotted line. The kneading section 62 corresponds to the region in the cylinder 22 where the resin material 52 supplied from the hopper 25 into the cylinder 22 is plasticized and becomes molten resin, and can be considered a plasticizing section. In the cylinder 22 of the extruder 21, the kneading section 62 is located downstream of the connection point of the hopper 25 and upstream of the connection point of the connection section 31.

[0042] Within the cylinder 22, upstream of the mixing section 62, the resin material 52 inside the cylinder 22 is still in a solid state and has not yet melted. However, in the mixing section 62, the resin material 52 is plasticized and becomes molten (molten resin), and downstream of the mixing section 62, the resin material 52 inside the cylinder 22 is molten resin. Therefore, arrow 74 in Figure 2 indicates the flow of solid resin material 52, and arrow 75 in Figure 2 indicates the flow of molten resin material 52 (molten resin).

[0043] As the material (residual resin) extruded from the tip of cylinder 12 is supplied into cylinder 22 through the connection part 31, the resin material 52 supplied from hopper 25 into cylinder 22 is mixed with the material (residual resin) supplied from the tip of cylinder 12 through the connection part 31 into cylinder 22 by screw 23 to form a resin mixture. That is, the screw 23 inside cylinder 22 mixes the resin material 52 supplied from hopper 25 into cylinder 22 and the material (residual resin) supplied from cylinder 12 through the connection part 31 into cylinder 22 to form a resin mixture, and the formed resin mixture is conveyed by screw 23 towards the tip side (downstream side) inside cylinder 22. The formed resin mixture is in a molten state (molten resin). Arrow 76 in Figure 2 shows the flow of this resin mixture.

[0044] Therefore, within the cylinder 22, upstream of the connection position of the connection part 31, the molten resin is composed of the resin components contained in the resin material 52, but downstream of the connection position of the connection part 31, the molten resin (resin mixture) is a mixture of the resin components contained in the resin material 51, the resin components contained in the resin material 52, and the filler contained in the resin material 51.

[0045] The temperature of the cylinder 22 of the extruder 21 is set lower than the thermal decomposition temperature of the residue resin (73) downstream of the point where the residue resin (73) is supplied to the cylinder 22 (i.e., the connection point of the connection part 31). In other words, the temperature of the cylinder 22 downstream of the point where the residue resin (73) is supplied (i.e., the connection point of the connection part 31) is set to a temperature lower than the thermal decomposition temperature of the residue resin (73) (for example, 100 to 300°C). The temperature of the cylinder 22 of the extruder 21 can be controlled by the control unit 28 controlling the temperature control mechanism of the cylinder 22. Hereinafter, when we refer to "the set temperature of the cylinder 22", we mean "the temperature of the cylinder 22 downstream of the point where the residue resin (73) extruded from the cylinder 12 of the extruder 11 is supplied to the cylinder 22 (i.e., the connection point of the connection part 31)". The temperature of the cylinder 22 upstream of the point where the residue resin (73) is supplied (i.e., the connection point of the connection part 31) can be set to an appropriate temperature as needed. Furthermore, since the resin components contained in the residual resin (73) extruded from the cylinder 12 of the extruder 11 are the same as the resin components contained in the resin material 51, the thermal decomposition temperature of the residual resin (73) supplied from the extruder 11 to the cylinder 22 of the extruder 21 is substantially the same as the thermal decomposition temperature T1 of the resin material 51.

[0046] By setting the temperature of cylinder 22 to a temperature lower than the thermal decomposition temperature of the residual resin (73), the residual resin (73) extruded from cylinder 12 of extruder 11 and supplied to cylinder 22 of extruder 21 is not heated to a temperature above the thermal decomposition temperature of the residual resin within cylinder 22, and therefore hardly decomposes within cylinder 22. This suppresses or prevents the thermal decomposition of the molten resin (resin mixture) within cylinder 22 and the generation of monogas. Furthermore, the fillers contained in the molten resin within cylinder 22 are not thermally decomposed.

[0047] Furthermore, it is more preferable that the set temperature of the cylinder 22 be lower than the thermal decomposition temperature of the residual resin and lower than the thermal decomposition temperature T2 of the resin material 52 (for example, 100 to 300°C). As a result, the resin components in the molten resin (resin mixture) sent forward by the rotation of the screw 13 in the cylinder 12 are not heated to a temperature above the thermal decomposition temperature of the residual resin (73), nor are they heated to a temperature above the thermal decomposition temperature T2 of the resin material 52, and therefore hardly decompose. This further suppresses or prevents the generation of monogas due to the thermal decomposition of the molten resin (resin mixture) in the cylinder 22.

[0048] Furthermore, it is preferable that the set temperature of cylinder 22 of extruder 2 be higher than the temperature at which the monogas generated in cylinder 12 of extruder 1 liquefies. In other words, the set temperature of cylinder 22 is set to a temperature (for example, 100 to 300°C) such that the monogas generated in cylinder 12 and flowing into cylinder 22 from cylinder 12 through the connection part 31 does not liquefy in cylinder 22. This suppresses or prevents the monogas generated in cylinder 12 and flowing into cylinder 22 from cylinder 12 through the connection part 31 from liquefying in cylinder 22. The monogas generated in cylinder 12 and flowing into cylinder 22 from cylinder 12 through the connection part 31 is discharged outside cylinder 22 from the gas discharge part 27 of cylinder 22 and sent to the heat exchanger 44 through the gas piping 46. The molten resin (resin mixture) is propelled forward by the rotation of the screw 23 within the cylinder 22 and extruded from the die 26 attached to the tip of the cylinder 22. At this time, the molten resin (resin mixture) is formed into a string shape by the die 26 and extruded from the die 26 as a strand (resin strand) 53. The strand 53 is the material extruded from the extruder 21 and also contains the residual resin supplied from the extruder 11 to the extruder 21.

[0049] The strand 53 extruded from the die 26 is cooled and solidified in the cooling tank 42. The solidified strand 53 is cut to a predetermined length by the cutting device 43. This produces resin pellets 54. In the pellet manufacturing system 41, the resin processing device 1 can function as a strand manufacturing device.

[0050] If the resin material 51 supplied from the hopper 15 into the cylinder 12 contains filler, then the residual resin (73) extruded from the tip of the cylinder 12 and supplied to the cylinder 22 through the connection part 31 also contains that filler, so the strands 53 and resin pellets 54 also contain the filler that was contained in the resin material 51. Similarly, if the resin material 52 supplied from the hopper 25 into the cylinder 22 contains filler, then the strands 53 and resin pellets 54 also contain the filler that was contained in the resin material 52.

[0051] Monomagnesium gas sent from gas outlets 17, 27, and 32 through gas piping 46 to the heat exchanger 44 is cooled and liquefied in the heat exchanger 44, becoming liquid monomagnesium. The heat exchanger 44 can cool and liquefy the monomagnesium gas by exchanging heat with cooling water 48. The liquid monomagnesium produced in the heat exchanger 44 is sent through piping (liquid pipeline) 47 to a recovery container 45, where it is stored. The liquid monomagnesium stored in the recovery container 45 is taken out as needed and reused.

[0052] In this embodiment, a method for processing resin material was described in which resin pellets 54 are manufactured using strands 53 extruded from an extruder 21. In other embodiments, instead of manufacturing resin pellets 54 using strands 53 extruded from an extruder 21, the strands 53 extruded from the extruder 21 may be allowed to flow out, or the strands 53 extruded from the extruder 21 may be stored in a container (not shown). In that case, the solidified strands 53 can be discarded later.

[0053] <Background of the consideration> Figure 3 is an explanatory diagram showing the configuration of a processing system (processing device) 101 for resin materials such as waste plastics, as investigated by the present inventors.

[0054] The processing system 101 shown in Figure 3 comprises an extruder 111, a heat exchanger 144, and a recovery container 145. The extruder 111 comprises a cylinder 112, a screw built into the cylinder 112, a rotary drive mechanism 114 for rotating the screw inside the cylinder 112, a hopper 115 located upstream of the cylinder 112, and a gas discharge section 117 for discharging the gas generated inside the cylinder 112 to the outside of the cylinder 112. A tank (container) 118 for storing residue is attached to the tip of the cylinder 112 of the extruder 111.

[0055] Next, the operation of the processing system 101 shown in Figure 3 will be described.

[0056] Resin material 151 is supplied from hopper 115 into cylinder 112. The resin material 151 supplied from hopper 115 into cylinder 112 is, for example, crushed various used resin products, and waste plastic can be used. In addition to the resin component, the resin material 151 supplied from hopper 115 into cylinder 112 also contains fillers.

[0057] The resin material 151 supplied from the hopper 115 into the cylinder 112 is melted into molten resin as it is moved forward by the rotation of the screw within the cylinder 112. At this time, the temperature of the cylinder 112 is set to a temperature higher than the thermal decomposition temperature of the resin material 151. As a result, the molten resin in the cylinder 112 is thermally decomposed, and monogas is generated. The monogas generated in the cylinder 112 is discharged outside the cylinder 112 from the gas discharge section 117 and sent to the heat exchanger 144 through the gas piping 146.

[0058] Of the molten resin in cylinder 122, a portion is thermally decomposed into monogas, which is sent from gas discharge port 117 through gas piping 146 to heat exchanger 144. The remainder (molten resin that was not thermally decomposed) is pushed out as residual resin from the tip of cylinder 112 and flows into tank 118. In addition, fillers contained in the molten resin in cylinder 112 also flow into tank 118 from the tip of cylinder 112 along with the molten resin that was not thermally decomposed.

[0059] Furthermore, some of the monogas generated in cylinder 112 is sent from gas discharge port 117 through gas piping 146 to heat exchanger 144, while the remainder flows into tank 118 from the tip of cylinder 112 along with the molten resin that has not been thermally decomposed. The monogas that flows from cylinder 112 into tank 118 is discharged outside tank 118 from gas discharge port 119 provided in tank 118 and sent to heat exchanger 144 through gas piping 146.

[0060] Monomagnesium gas sent from gas outlets 117 and 119 through gas piping 146 to heat exchanger 144 is cooled and liquefied in heat exchanger 144, becoming liquid monomagnesium. Heat exchanger 144 can cool and liquefy monomagnesium gas by exchanging heat with cooling water 148. The liquid monomagnesium produced in heat exchanger 144 is sent through piping 147 to recovery container 145 and stored in recovery container 145. The liquid monomagnesium stored in recovery container 145 can be taken out and reused as needed.

[0061] As the processing system 101 shown in Figure 3 continues to operate, the amount of residual resin pushed out from the tip of the cylinder 112 and flowing into and stored in the tank 118 (hereinafter referred to as the storage amount) increases. As the storage amount in the tank 118 increases, it becomes necessary to remove the residual resin stored in the tank 118 and empty the tank 118 before the tank 118 becomes full.

[0062] During this operation, the extruder 111 must be stopped, which reduces the operational efficiency of the extruder 111 and the processing system 101 using it, thereby reducing the processing efficiency of resin materials such as waste plastics. In addition, this operation may increase the processing cost of resin materials such as waste plastics. Furthermore, when removing the residual resin stored in the tank 118, it is possible that the monogas inside the tank 118 will diffuse into the surroundings. If the monogas is a type of gas that should not diffuse into the surroundings, it is necessary to prevent the monogas inside the tank 118 from diffusing into the surroundings when removing the residual resin stored in the tank 118, but this makes the operation of removing the residual resin stored in the tank 118 more difficult and increases the burden associated with this operation.

[0063] <Main Features and Effects> The resin processing apparatus 1 of this embodiment includes an extruder 11 to which resin material 51 is supplied, and an extruder 21 to which the extruder 11 is connected and to which residual resin (73) discharged from the extruder 11 is supplied. Specifically, the cylinder 12 of the extruder 11 is connected to the cylinder 22 of the extruder 21 so that the residual resin discharged (extruded) from the tip of the cylinder 12 of the extruder 11 is supplied into the cylinder 22 of the extruder 11. In the case of Figure 1 above, the cylinder 12 of the extruder 11 is connected to the cylinder 22 of the extruder 21 via a connecting part 31, and the residual resin (73) discharged (extruded) from the tip of the cylinder 12 is supplied into the cylinder 22 of the extruder 21 through the connecting part 31.

[0064] One of the main features of this embodiment is that the temperature of the cylinder of the extruder 11 is set higher than the thermal decomposition temperature T1 of the resin material 51 downstream of the kneading section 61, and the temperature of the cylinder 22 of the extruder 21 is set lower than the thermal decomposition temperature of the residual resin (73) downstream of the position where the residual resin (73) is supplied.

[0065] Of the extruders 11 and 21 that make up the resin processing apparatus 1, extruder 11 is used to thermally decompose the resin material 51, and extruder 21 is used to process the residual resin (i.e., the residue after thermal decomposition) discharged from the cylinder 12 of extruder 11. In the case of Figure 2 above, extruder 21 is used to manufacture resin pellets using the residual resin discharged from the cylinder 12 of extruder 11.

[0066] Unlike this embodiment, if the set temperature of the cylinder 12 is set lower than the thermal decomposition temperature T1 of the resin material 51, the resin material 51 will hardly decompose within the cylinder 12, and therefore almost no monomer gas will be generated within the cylinder 12. In this case, almost no monomer gas will be discharged outside the cylinder 12 from the gas discharge section 17 or the gas discharge section 32, making it difficult to recover the monomer liquefied in the heat exchanger 44.

[0067] In contrast, in this embodiment, in the extruder 11 whose purpose is the thermal decomposition of the resin material 51, the set temperature of the cylinder 12 (the set temperature of the cylinder 12 downstream of the mixing section 61) is set higher than the thermal decomposition temperature T1 of the resin material 51 so that the thermal decomposition of the resin material 51 is carried out accurately within the cylinder 12. As a result, the resin components contained in the resin material 51 supplied from the hopper 15 into the cylinder 12 are heated to a temperature higher than the thermal decomposition temperature T1, causing thermal decomposition and the generation of monomer gas. At least a portion of the generated monomer gas can be discharged from the gas discharge section 17 provided in the cylinder 12 and the gas discharge section 32 provided in the connection section 31. The monomer gas discharged from the gas discharge section 17 and the gas discharge section 32 can be liquefied in the heat exchanger 44. The monomer liquefied in the heat exchanger 44 can be stored in a recovery container 45 or the like for reuse.

[0068] On the other hand, the set temperature of the cylinder 22 of the extruder 21 is set to a temperature lower than the thermal decomposition temperature of the residual resin (73) discharged from the extruder 11 and supplied to the cylinder 22, so that the residual resin does not thermally decompose within the cylinder 22. Preferably, the set temperature of the cylinder 22 of the extruder 21 is set to a temperature lower than the thermal decomposition temperature of the residual resin and lower than the thermal decomposition temperature T2 of the resin material 52, so that thermal decomposition does not occur not only of the residual resin (73) supplied from the extruder 11 to the cylinder 22 but also of the resin material 52.

[0069] Unlike this embodiment, when the set temperature of the cylinder 22 is set to a temperature higher than the thermal decomposition temperature of the residual resin (73) supplied from the extruder 11 to the cylinder 22, or when the set temperature of the cylinder 22 is set to a temperature higher than the thermal decomposition temperature T2 of the resin material 52, monogas is generated as the resin components are thermally decomposed in the cylinder 22. As a result, the ratio of resin components in the resin mixture formed in the cylinder 22 decreases by the amount of monogas generated. When the ratio of resin components in the resin mixture formed in the cylinder 22 decreases, it becomes difficult to stably transport the resin mixture by the screw 23 in the cylinder 22, and it also becomes difficult to stably extrude the resin mixture from the die 26 connected to the tip of the cylinder 22. Furthermore, when monogas is generated in the cylinder 22, there is a possibility that the monogas generated in the cylinder 22 may leak out of the cylinder 22 into the atmosphere.

[0070] In contrast, in this embodiment, the set temperature of the cylinder 22 of the extruder 21 is set to a temperature lower than the thermal decomposition temperature of the residue resin (73) supplied from the extruder 11 to the cylinder 22. It is more preferable to set the set temperature of the cylinder 22 of the extruder 21 to a temperature lower than the thermal decomposition temperature of the residue resin (73) and also lower than the thermal decomposition temperature T2 of the resin material 52. This makes it possible to suppress or prevent the thermal decomposition of resin components within the cylinder 22. That is, by setting the set temperature of the cylinder 22 lower than the thermal decomposition temperature of the residue resin (73), it is possible to suppress or prevent the thermal decomposition of resin components contained in the residue resin (73) discharged from the extruder 11 and supplied to the cylinder 22 within the cylinder 22. Furthermore, by setting the set temperature of the cylinder 22 lower than the thermal decomposition temperature T2 of the resin material 52, it is possible to suppress or prevent the thermal decomposition of resin components contained in the resin material 52 supplied from the hopper 25 into the cylinder 22 within the cylinder 22. This effectively suppresses or prevents the generation of monogas due to the thermal decomposition of resin components within the cylinder 22, thereby more effectively preventing the monogas generated within the cylinder 22 from leaking into the atmosphere. Furthermore, it suppresses or prevents the ratio of resin components in the resin mixture formed within the cylinder 22 from decreasing due to thermal decomposition, enabling stable and accurate transport of the resin mixture within the cylinder 22 by the screw 23, and enabling stable and accurate extrusion of the resin mixture from the die 26 connected to the tip of the cylinder 22. By cutting the resin mixture (strand 53) extruded from the die 26 with a cutting device 43, resin pellets 54 can be accurately formed. As a result, the operation of the resin processing apparatus 1 is stable, and resin pellets 54 can be manufactured stably.

[0071] In this embodiment, the resin material 52 supplied from the hopper 25 into the cylinder 22 and the residual resin (73) extruded from the cylinder 12 and supplied into the cylinder 22 are kneaded by a screw 23 to form a resin mixture, and this resin mixture is extruded from a die 26 connected to the tip of the cylinder 22. The residual resin (73) extruded from the cylinder 12 and supplied into the cylinder 22 has a considerably low resin content. This is because the resin material 51 is thermally decomposed in the cylinder 12 to generate monogas, so the resin content in the residual resin (73) extruded from the cylinder 12 and supplied into the cylinder 22 is considerably lower than the resin content of the resin material 51 at the stage when it is supplied from the hopper 15 into the cylinder 12. Therefore, unlike this embodiment, if no resin material is supplied from the hopper 25 into the cylinder 22, the residual resin (i.e., material with a very low resin content) that is pushed out from the cylinder 12 and supplied into the cylinder 22 is transported by the screw 23 and pushed out from the die 26 connected to the tip of the cylinder 22. However, it is difficult to stably transport material with a very low resin content by the screw 23 and to stably push out material with a very low resin content from the die 26.

[0072] In contrast, in this embodiment, the resin material 52 is supplied from the hopper 25 into the cylinder 22. The resin material 52 supplied from the hopper 25 into the cylinder 22 and the residual resin (73) extruded from the cylinder 12 and supplied to the cylinder 22 are kneaded by the screw 23 within the cylinder 22 to form a resin mixture. Therefore, even if the resin component content in the residual resin (73) supplied from the cylinder 12 to the cylinder 22 is quite low, the resin component content in the resin mixture formed within the cylinder 22 can be made higher than the resin component content in the residual resin (73) supplied from the cylinder 12 to the cylinder 22. As a result, the resin mixture formed within the cylinder 22 can be stably conveyed by the screw 23 and stably extruded from the die 26 connected to the tip of the cylinder 22. Therefore, the operation of the resin processing apparatus 1 is stable, and resin pellets 54 can be stably manufactured.

[0073] Unlike this embodiment, let's consider a case where a molding die is connected to the tip of the cylinder 12, and pellets are manufactured by cutting the strands extruded from the die. In this case, the material to be extruded from the die connected to the tip of the cylinder 12 has a low resin content, making it difficult to extrude it stably from the die connected to the tip of the cylinder 12. In addition, there is a possibility that monomer gas generated in the cylinder 12 may leak from the die into the atmosphere. Furthermore, in order to increase the resin content of the material to be extruded from the die connected to the tip of the cylinder 12, it is necessary to suppress the thermal decomposition of the resin material 51 in the cylinder 12, but this will reduce the amount of monomer gas generated in the cylinder 12, thus reducing the amount of monomer recovered by liquefying the monomer gas in the heat exchanger 44. Moreover, since the set temperature of the cylinder 12 is set higher than the thermal decomposition temperature T1 of the resin material 51 in order to accurately thermally decompose the resin material 51, it is difficult to strictly control the resin content of the material extruded from the cylinder 12. Therefore, it is not advisable to connect a molding die to the tip of the cylinder 12 and cut the strand extruded from the die to produce pellets.

[0074] In contrast, in this embodiment, of the extruders 11 and 21 that constitute the resin processing apparatus 1, the extruder 11 equipped with a cylinder 12 is used to thermally decompose the resin material 51, and the extruder 21 equipped with a cylinder 22 is used to manufacture resin pellets using the residual resin extruded from the cylinder 12 of the extruder 11. Resin material 52 is supplied from the hopper 25 into the cylinder 22 of the extruder 21 so that resin pellets can be manufactured using the residual resin supplied from the cylinder 12 of the extruder 11 to the cylinder 22 of the extruder 21. This allows the resin material 52 supplied from the hopper 25 into the cylinder 22 and the residual resin supplied from the cylinder 12 to the cylinder 22 to be kneaded to form a resin mixture, which can then be stably extruded from the die 26 connected to the tip of the cylinder 22. Furthermore, it is possible to more effectively prevent the monogas generated in the cylinder 12 from leaking into the atmosphere.

[0075] In the processing system 101 of the above example, the residual resin extruded from the tip of the cylinder 112 of the extruder 111 is stored in the tank 118. Therefore, as the amount of resin stored in the tank 118 increases, it becomes necessary to remove the residual resin stored in the tank 118 and empty the tank 118 before the tank 118 becomes full.

[0076] In contrast, in this embodiment, the residual resin extruded from the tip of cylinder 12 is supplied to cylinder 22, to which cylinder 12 is connected. The residual resin supplied from cylinder 12 to cylinder 22 and the resin material 52 supplied from hopper 25 to cylinder 22 are kneaded by screw 23 to form a resin mixture, which is then extruded through die 26 connected to the tip of cylinder 22 and cut to produce resin pellets 54. Therefore, the operation required in the processing system 101 of the above study example, such as removing the material stored in tank 118 and emptying tank 118, is unnecessary. Since the resin processing device 1 can be operated continuously for a long time, the operating efficiency of the resin processing device 1 and the pellet manufacturing system 41 including it can be increased. In addition, the processing efficiency of the resin material 51 can be improved. When waste plastic is used as the resin material 51, the processing efficiency of the waste plastic can be improved, and the processing cost of waste plastic can be reduced. Therefore, resin materials such as waste plastic can be processed and recycled efficiently. Furthermore, since the residual resin extruded from the tip of cylinder 12 is supplied to cylinder 22 to which cylinder 12 is connected, it becomes easier to prevent the monogas generated in cylinder 12 from diffusing into the surroundings.

[0077] Next, we will explain how the monogas generated in cylinder 12 can be prevented from diffusing into the surroundings.

[0078] In cylinder 12, the kneading section 61 is located downstream of the connection point of hopper 15 and upstream of the gas discharge section 17. If there is no gas discharge section 17, as shown in Figure 1 below, the kneading section 61 is located downstream of the tip of cylinder 12. In the kneading section 61 of cylinder 12, the molten resin formed by the plasticization of the resin material 51 fills the transport space within cylinder 12 (the space in which the resin material is transported by the screw 13). Therefore, the monogas generated by the thermal decomposition of the molten resin in cylinder 12 cannot pass over the kneading section 61 and return to the upstream side of the kneading section 61 within cylinder 12, and thus, the monogas can be prevented from being discharged to the outside from hopper 15. The monogas generated by the thermal decomposition of the molten resin in cylinder 12 is discharged from the gas discharge section 17 or gas discharge section 32, or supplied into cylinder 22 from the tip of cylinder 12 through the connection section 31.

[0079] Furthermore, in cylinder 22, the kneading section 61 is located downstream of the connection point of hopper 25 and upstream of the connection point of connection section 31. In the kneading section 61 of cylinder 22, the molten resin formed by the plasticization of the resin material 52 fills the transport space within cylinder 22 (the space in which the resin material is transported by the screw 23). For this reason, monomagnesium gas supplied from the tip of cylinder 12 through connection section 31 into cylinder 22 cannot pass over the kneading section 61 within cylinder 22 and return to the upstream side of the kneading section 61. In addition, the resin mixture (molten resin) formed in cylinder 22 is pushed out from the holes (resin discharge ports) of die 26, but the holes of die 26 and the resin flow path in front of those holes are filled with the resin mixture (molten resin). For this reason, monomagnesium gas supplied from the tip of cylinder 12 through connection section 31 into cylinder 22 cannot pass through the holes of die 26 or the resin flow path, and therefore is not discharged to the outside from the holes of die 26. Therefore, the monogas supplied from the tip of the cylinder 12 through the connection part 31 into the cylinder 22 is discharged outside the cylinder 22 from the gas discharge part 27, preventing the monogas from being discharged to the outside from the hopper 25 or die 26.

[0080] Furthermore, while the cylinder 22 is designed to suppress or prevent the generation of monogas due to the thermal decomposition of molten resin, even if monogas were to be generated by the thermal decomposition of molten resin within the cylinder 22, that monogas could not pass beyond the kneading section 62 and return to the upstream side of the kneading section 61 within the cylinder 22, nor could it pass through the holes in the die 26 or the resin flow path. Therefore, the monogas is discharged outside the cylinder 22 from the gas discharge section 27.

[0081] Therefore, the entire amount of monogas generated by the thermal decomposition of the resin material 51 in cylinder 12 can be sent from gas discharge sections 17, 27, and 32 through gas piping 46 to the heat exchanger 44 for liquefaction, and then stored and recovered in the recovery container 45. Thus, it is possible to prevent the monogas generated by thermal decomposition in cylinder 12 from diffusing into the surroundings. Furthermore, even if monogas is generated by thermal decomposition in cylinder 22, the entire amount of that monogas can be sent from gas discharge section 27 through gas piping 46 to the heat exchanger 44 for liquefaction, and then stored and recovered in the recovery container 45. Thus, even if monogas is generated by thermal decomposition in cylinder 22, it is possible to prevent that monogas from diffusing into the surroundings.

[0082] <Variation> Modifications of this embodiment will now be described. Figure 4 is an explanatory diagram (side view) showing a first modification of the resin processing apparatus 1 of this embodiment. Figure 5 is an explanatory diagram (top view) showing a second modification of the resin processing apparatus 1 of this embodiment. Note that in Figure 4, the control units 18 and 28 are omitted for simplification, and in Figure 5, the screws 13 and 23 in the cylinders 12 and 22 and the control units 18 and 28 are omitted. In addition, in Figures 4 and 5, the cooling tank 42 and the cutting device 43 are also shown for ease of understanding.

[0083] Note that Figures 1, 4, and 5, as well as Figures 6 and 7 described later, show two of the X, Y, and Z directions. The X, Y, and Z directions are mutually orthogonal. Of these, the X and Y directions are horizontal, and the Z direction is vertical.

[0084] In both Figure 1 and Figure 4 (first modified example), the long axis direction of cylinder 12 and the long axis direction of cylinder 22 are the same, and in this case, they are in the X direction. However, in Figure 1, the transport direction of the resin material inside cylinder 12 and the transport direction of the resin material inside cylinder 22 are the same, whereas in Figure 4 (first modified example), the transport direction of the resin material inside cylinder 12 and the transport direction of the resin material inside cylinder 22 are opposite to each other.

[0085] In other words, in the case of Figure 1, the direction from upstream to downstream in cylinder 12 and the direction from upstream to downstream in cylinder 22 are the same. Specifically, in the case of Figure 1, the resin material is transported from the left side of the figure to the right side in both cylinder 12 and cylinder 22. On the other hand, in the case of Figure 4 (first modified example), the direction from upstream to downstream in cylinder 12 and the direction from upstream to downstream in cylinder 22 are opposite directions. Specifically, in the case of Figure 4 (first modified example), the resin material is transported from the right side of the figure to the left side in cylinder 12, and the resin material is transported from the left side of the figure to the right side in cylinder 22.

[0086] Furthermore, in the case of Figure 5 (second modified example), the long axis direction of cylinder 12 and the long axis direction of cylinder 22 are in directions that intersect each other, for example, in directions that are perpendicular to each other. Here, the long axis direction of cylinder 12 is the Y direction, and the long axis direction of cylinder 22 is the X direction.

[0087] The long axis direction of the cylinder 12 refers to the direction of the long side or longitudinal direction of the cylinder 12, and the cylindrical cylinder 12 extends in the direction of its long axis direction. The long axis direction of the cylinder 12 and the long axis direction of the screw 13 inside the cylinder 12 are the same, and the long axis direction of the screw 13 corresponds to the axis direction of the screw 13's rotation axis. Inside the cylinder 12, the resin material is conveyed from the upstream side to the downstream side in the long axis direction by the rotating screw 13.

[0088] Furthermore, the long axis direction of the cylinder 22 refers to the direction of the long side or longitudinal direction of the cylinder 22, and the cylindrical cylinder 22 extends in the direction of its long axis. The long axis direction of the cylinder 22 and the long axis direction of the screw 23 inside the cylinder 22 are the same, and the long axis direction of the screw 23 corresponds to the axis direction of the screw 23's rotation axis. Inside the cylinder 22, the resin material is conveyed from the upstream side to the downstream side in the long axis direction by the rotating screw 23.

[0089] The advantages of each case—Figure 1, Figure 4 (first modified example), and Figure 5 (second modified example)—are explained below.

[0090] In the case of Figure 1, the dimensions of the entire resin processing apparatus 1 in the Y direction can be reduced compared to the case of Figure 5 (second modified example). Therefore, in the case of Figure 1, the dimensions of the planar area required to install the resin processing apparatus 1, the cooling tank 42, and the cutting device 43 can be reduced compared to the case of Figure 5 (second modified example).

[0091] In the case of Figure 4 (first modified example), the Y-direction dimension of the entire resin processing apparatus 1 can be reduced compared to the case of Figure 5 (second modified example). Also, in the case of Figure 4 (first modified example), the X-direction dimension of the entire resin processing apparatus 1 can be reduced compared to the case of Figure 1. For this reason, in the case of Figure 4 (first modified example), the Y-direction dimension of the planar area required to install the resin processing apparatus 1, cooling tank 42, and cutting device 43 can be reduced compared to the case of Figure 5 (second modified example), and the X-direction dimension of the planar area required to install the resin processing apparatus 1, cooling tank 42, and cutting device 43 can be reduced compared to the case of Figure 1.

[0092] In the case of Figure 5 (second modified example), the hopper 25 for supplying the resin material 52 to the cylinder 22 does not overlap with the cylinder 12 in a plan view, so the cylinder 12 does not get in the way when loading the resin material 52 into the hopper 25. This makes it easier to load the resin material 52 into the hopper 25. Also, in the case of Figure 5 (second modified example), the extruder 11 does not get in the way when arranging the cooling tank 42 and the cutting device 43 in a position adjacent to the extruder 21 in the X direction. This makes it easier to arrange the resin processing apparatus 1, the cooling tank 42 and the cutting device 43.

[0093] Furthermore, in the case of Figure 1, if the height difference between cylinder 12 and cylinder 22 is small, it becomes difficult to feed the resin material 52 into the hopper 25, so it is necessary to ensure a certain height difference between cylinder 12 and cylinder 22. In contrast, in the case of Figure 5 (second modified example), even if the height difference between cylinder 12 and cylinder 22 is small, cylinder 12 does not get in the way of feeding the resin material 52 into the hopper 25. For this reason, in the case of Figure 5 (second modified example), it is possible to reduce the height difference between cylinder 12 and cylinder 22 compared to the case of Figure 1.

[0094] Furthermore, in the case of Figure 4 (first modified example), if the cooling tank 42 and cutting device 43 are to be placed adjacent to the extruder 21 in the X direction, there is a risk that the cooling tank 42 and cutting device 43 will overlap with the cylinder 12 in a plan view. Therefore, to prevent the cylinder 12 from getting in the way, it becomes necessary to increase the height difference between cylinder 12 and cylinder 22. For this reason, from the standpoint of being able to reduce the height difference between cylinder 12 and cylinder 22, the case of Figure 1 is more advantageous than the case of Figure 4 (first modified example), and the case of Figure 5 (second modified example) is even more advantageous.

[0095] Figures 6 and 7 are explanatory diagrams showing a third modified example of the resin processing apparatus 1 of this embodiment.

[0096] In the cases shown in Figures 1, 4 (first modified example), and 5 (second modified example), the height of cylinder 12 is higher than the height of cylinder 22, cylinder 12 is connected to cylinder 22 via a connecting portion 31, and the material extruded from cylinder 12 is supplied into cylinder 22 through the connecting portion 31.

[0097] In contrast, in the third example shown in Figures 6 and 7, the height of cylinder 12 is approximately the same as the height of cylinder 22, cylinder 12 is directly connected to cylinder 22 without the need for a connecting part 31, and the material extruded from the tip of cylinder 12 is directly supplied into cylinder 22.

[0098] Specifically, in the third example shown in Figures 6 and 7, the long axis directions of cylinder 12 and cylinder 22 are in directions that intersect each other, preferably in directions that are perpendicular to each other. Here, the long axis direction of cylinder 12 is the Y direction, and the long axis direction of cylinder 22 is the X direction. The height position of cylinder 12 is approximately the same as the height position of cylinder 22, and the tip of cylinder 12 faces the side surface of cylinder 22 and is connected to that side surface. Cylinder 22 has an opening (opening for cylinder 12) at the position to which cylinder 12 is connected, and cylinder 12 is connected so as to communicate with this opening. As a result, the material extruded from the tip of cylinder 12 is supplied into cylinder 22 through the opening (opening for cylinder 12) of cylinder 22.

[0099] In the case of the resin processing apparatus 1 of the third study example shown in Figures 6 and 7, almost the same effects can be obtained as in the case of the resin processing apparatus 1 shown in Figure 1. Furthermore, in the case of the resin processing apparatus 1 of the third study example shown in Figures 6 and 7, since the height position of cylinder 12 and the height position of cylinder 22 are almost the same, the height positions of the extruders 11 and 21 that constitute the resin processing apparatus 1 can be made the same. For this reason, the arrangement (installation) of the extruders 11 and 21 that constitute the resin processing apparatus 1 is easy. On the other hand, in the case of the resin processing apparatus 1 shown in Figure 1, since cylinder 12 is connected to cylinder 22 via the connecting part 31, it becomes easier to connect cylinder 12 to cylinder 22, and it also becomes easier to adjust the relative positional relationship between cylinder 12 and cylinder 22.

[0100] Furthermore, in all cases, including Figure 1, Figure 4 (first modified example), Figure 5 (second modified example), and Figure 6 (third example), it is preferable that the length of cylinder 12 (length in the long axis direction) is longer than the length of cylinder 22 (length in the long axis direction). In cylinder 12, it is desirable to sufficiently thermally decompose the resin material 51 to increase the amount of monogas generated, and for this purpose, it is desirable that the length of cylinder 12 be somewhat long. On the other hand, in cylinder 22, it is sufficient that the resin material 52 supplied from hopper 15 to cylinder 22 and the material supplied from cylinder 12 to cylinder 22 be mixed to the extent that no problems occur in the formation of strand 42. For this reason, the length of cylinder 12 does not need to be very long. Therefore, by increasing the length of cylinder 12, the amount of monogas generated in cylinder 12 can be increased, and by making the length of cylinder 22 shorter than the length of cylinder 12, the overall dimensions of the resin processing apparatus 1 can be suppressed.

[0101] Figure 8 is an explanatory diagram showing a fourth modified example of the resin processing apparatus 1 and pellet manufacturing system 41 using the same according to this embodiment. Figure 9 is an explanatory diagram showing a fifth modified example of the resin processing apparatus 1 and pellet manufacturing system 41 using the same according to this embodiment. Figure 10 is an explanatory diagram showing a sixth modified example of the resin processing apparatus 1 and pellet manufacturing system 41 using the same according to this embodiment. Figures 8 to 10 correspond to Figure 2 above.

[0102] In the case of Figure 8 (fourth modified example), the cylinder 22 of the extruder 21 is not provided with a gas discharge section 27, and therefore, the gas piping 46 connected to the gas discharge section 27 is not provided. In the case of Figure 9 (fifth modified example), the cylinder 22 of the extruder 21 is not provided with a gas discharge section 27, and the connection section 31 is not provided with a gas discharge section 32, and therefore, the gas piping 46 connected to the gas discharge section 27 and the gas piping 46 connected to the gas discharge section 32 are not provided. In the case of Figure 10 (sixth modified example), the cylinder 22 of the extruder 21 is not provided with a gas discharge section 27, and the cylinder 12 of the extruder 11 is not provided with a gas discharge section 17, and therefore, the gas piping 46 connected to the gas discharge section 17 and the gas piping 46 connected to the gas discharge section 27 are not provided. Otherwise, the configuration of the resin processing apparatus 1 and the pellet manufacturing system 41 using it are the same as in Figure 2 above.

[0103] Comparing the cases of Figure 2, Figure 8 (fourth modified example), Figure 9 (fifth modified example), and Figure 10 (sixth modified example), the case of Figure 2 is the most efficient in terms of recovering the monogas generated by the resin processing apparatus 1. In the case of Figure 2, the monogas generated by the resin processing apparatus 1 can be recovered from the gas discharge section 17 provided on the cylinder 12 of the extruder 11, the gas discharge section 32 provided on the connection section 31, and the gas discharge section 27 provided on the cylinder 22 of the extruder 21.

[0104] Furthermore, in the case of Figure 8 (fourth modified example), the recovery efficiency of monogas generated in the resin processing apparatus 1 is most easily achieved compared to the cases of Figure 9 (fifth modified example) and Figure 10 (sixth modified example). This is because, in the case of Figure 8 (fourth modified example), monogas generated in the resin processing apparatus 1 can be recovered from both the gas discharge section 17 provided on the cylinder 12 of the extruder 11 and the gas discharge section 32 provided on the connection section 31. Also, in the case of Figure 8 (fourth modified example), there is no need to provide a gas discharge section 27 on the cylinder 22 of the extruder 21, and therefore, there is no need for gas piping 46 connected to the gas discharge section 27. As a result, the configuration of the resin processing apparatus 1 and the pellet manufacturing system 41 using it can be simplified compared to the case of Figure 2.

[0105] Furthermore, in the case of Figure 9 (5th modified example), the monogas generated in the resin processing apparatus 1 can be recovered from the gas discharge section 17 provided in the cylinder 12 of the extruder 11. Also, in the case of Figure 10 (6th modified example), the monogas generated in the resin processing apparatus 1 can be recovered from the gas discharge section 32 provided in the connection section 31. In the cases of Figure 9 (5th modified example) and Figure 10 (6th modified example), the configuration of the resin processing apparatus 1 and the pellet manufacturing system 41 using it can be further simplified compared to the case of Figure 8 (4th modified example).

[0106] The present inventors have described the invention in detail based on its embodiments, but it goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from its essence. [Explanation of Symbols]

[0107] 1. Resin processing equipment 11,21 Extruder 12.22 liters 13,23 Screw 14,24 Rotary drive mechanism 15,25 Hoppa 26 Die 17,27 Gas discharge section 18,28 Control Unit 31 Connection part 32 Gas discharge section 41 Pellet Manufacturing System 42 Cooling tank 43 Cutting device 44 Heat exchanger 45 Collection containers 46 Gas piping 47 Piping 48 Cooling water 51, 52 Resin materials 53 Strand 54 resin pellets 61, 62 Mixing section 101 Processing System 111 Extruder 112 Cylinder 114 Rotary drive mechanism 115 Hoppers 117,119 Gas discharge section 118 tanks 144 Heat exchanger 145 Collection containers 146 Gas piping 147 Piping 148 Cooling water 151 Resin materials

Claims

1. A first extruder to which a first resin material is supplied, The first extruder is connected to a second extruder to which the residual resin discharged from the first extruder is supplied, Includes, The temperature of the cylinder of the first extruder is set to be higher than the thermal decomposition temperature of the first resin material downstream of the first kneading section. The temperature of the cylinder of the second extruder is set lower than the thermal decomposition temperature of the residual resin downstream of the position where the residual resin is supplied. The second extruder has a second supply unit for supplying a second resin material into the cylinder of the second extruder, The second supply unit is located upstream of the position in the cylinder of the second extruder where the residual resin is supplied, in a resin processing apparatus.

2. In the resin processing apparatus according to claim 1, A resin processing apparatus in which the first resin material is plasticized in the first kneading section of the cylinder of the first extruder.

3. In the resin processing apparatus according to claim 1, The first extruder is, A first supply unit for supplying the first resin material into the cylinder of the first extruder, A first gas discharge unit is provided in the cylinder of the first extruder for discharging the gas generated in the cylinder of the first extruder, It has, The first kneading section is located in the cylinder of the first extruder downstream of the first supply section and upstream of the first gas discharge section in a resin processing apparatus.

4. In the resin processing apparatus according to claim 1, The cylinder of the first extruder and the cylinder of the second extruder are connected via a connecting portion. A resin processing apparatus wherein the residual resin discharged from the tip of the cylinder of the first extruder is supplied to the cylinder of the second extruder through the connecting portion.

5. In the resin processing apparatus according to claim 4, A resin processing apparatus is provided in which a second gas discharge section is provided at the connection section for discharging gas generated in the cylinder of the first extruder.

6. In the resin processing apparatus according to claim 1, A resin processing apparatus wherein the temperature of the cylinder of the second extruder is set lower than the thermal decomposition temperature of the second resin material downstream of the position where the residual resin is supplied.

7. In the resin processing apparatus according to claim 6, A resin processing apparatus wherein the temperature of the cylinder of the second extruder is set to be higher than the liquefaction temperature of the monogas generated in the cylinder of the first extruder downstream of the position where the residual resin is supplied.

8. In the resin processing apparatus according to claim 1, The second extruder has a third gas discharge section for discharging gas that has flowed from the cylinder of the first extruder into the cylinder of the second extruder, The resin processing apparatus wherein the third gas discharge section is located downstream of the position in the cylinder of the second extruder where the residual resin is supplied.

9. In the resin processing apparatus according to claim 1, A resin processing apparatus in which the longitudinal axis direction of the cylinder of the first extruder and the longitudinal axis direction of the cylinder of the second extruder are the same as each other.

10. In the resin processing apparatus according to claim 1, A resin processing apparatus in which the longitudinal axis direction of the cylinder of the first extruder and the longitudinal axis direction of the cylinder of the second extruder are perpendicular to each other.

11. In the resin processing apparatus according to claim 1, A resin processing apparatus in which the length of the cylinder of the first extruder is longer than the length of the cylinder of the second extruder.

12. A method for manufacturing resin pellets, including the following steps: (a) A step of supplying a first resin material into the cylinder of a first extruder; (b) After step (a), supply the residual resin discharged from the cylinder of the first extruder to the cylinder of the second extruder to which the cylinder of the first extruder is connected; (c) A step of supplying a second resin material into the cylinder of the second extruder; (d) After steps (b) and (c), a step of kneading the second resin material and the residual resin supplied from the first extruder cylinder in the cylinder of the second extruder to form a resin mixture; and (e) After step (d), a step of cutting the material extruded from the second extruder to form resin pellets, Here, The temperature of the cylinder of the first extruder is set to be higher than the thermal decomposition temperature of the first resin material downstream of the first kneading section. The temperature of the cylinder of the second extruder is set lower than the thermal decomposition temperature of the residual resin downstream of the position where the residual resin is supplied. In step (e), the resin mixture is extruded from the second extruder as the material.

13. In the method for producing resin pellets according to claim 12, (a1) After step (a) and before step (b), a step of transporting and melting the first resin material in the cylinder of the first extruder. It further includes, (a1) above is a method for manufacturing resin pellets, wherein the first resin material is plasticized in the first kneading section of the cylinder of the first extruder.

14. In the method for producing resin pellets according to claim 13, A method for manufacturing resin pellets, wherein the temperature of the cylinder of the second extruder is set to be higher than the liquefaction temperature of the monogas generated in the cylinder of the first extruder downstream of the position where the residual resin is supplied.

15. In the method for producing resin pellets according to claim 13, A method for manufacturing resin pellets, wherein the temperature of the cylinder of the second extruder is set lower than the thermal decomposition temperature of the second resin material downstream of the position where the residual resin is supplied.

16. In the method for producing resin pellets according to claim 13, A method for producing resin pellets, wherein the monogas discharged from the first extruder is liquefied in a heat exchanger.

17. In the method for producing resin pellets according to claim 13, The first resin material is made of waste plastic, and the method is a method for producing resin pellets.

18. A method for processing resin materials, including the following steps: (a) A step of supplying a first resin material into the cylinder of a first extruder; (b) After step (a), supply the residual resin discharged from the cylinder of the first extruder to the cylinder of the second extruder to which the cylinder of the first extruder is connected; (c) A step of supplying a second resin material into the cylinder of the second extruder; (d) After steps (b) and (c), a step of kneading the second resin material and the residual resin supplied from the first extruder cylinder in the cylinder of the second extruder to form a resin mixture; (e) a step of extruding the material containing the residual resin from the second extruder after step (d); and (f) A step of liquefying the mono gas discharged from the first extruder in a heat exchanger, Here, The temperature of the cylinder of the first extruder is set to be higher than the thermal decomposition temperature of the first resin material downstream of the first kneading section. The temperature of the cylinder of the second extruder is set lower than the thermal decomposition temperature of the residual resin downstream of the position where the residual resin is supplied. In step (e), the resin mixture is extruded from the second extruder as the material.

19. In the method for processing a resin material according to claim 18, (a1) After step (a) and before step (b), a step of transporting and melting the first resin material in the cylinder of the first extruder. It further includes, (a1) above is a method for processing a resin material, wherein the first resin material is plasticized in the first kneading section of the cylinder of the first extruder.

20. In the method for processing a resin material according to claim 19, A method for processing resin materials, wherein the temperature of the cylinder of the second extruder is set to be higher than the liquefaction temperature of the monogas generated in the cylinder of the first extruder downstream of the position where the residual resin is supplied.

21. In the method for processing a resin material according to claim 19, A method for processing resin materials, wherein the temperature of the cylinder of the second extruder is set lower than the thermal decomposition temperature of the second resin material downstream of the position where the residual resin is supplied.

22. In the method for processing a resin material according to claim 19, The first resin material is made of waste plastic, and the method for processing resin materials.

Images