Chemical recovery device and chemical recovery forming system

Abstract

The present invention relates to a chemical recovery device and a chemical recovery molding system, the chemical recovery device (100) comprising: a depolymerization reaction tank (300) for decomposing a first molded article comprising a polymer into a depolymerized product by a depolymerization reaction; a polymerization reaction tank (400) for synthesizing the depolymerized product into a polymer by a polymerization reaction; and a polymer supply unit (600) for supplying the polymer synthesized in the polymerization reaction tank (400) to an injection molding machine (1) for molding a second molded article. And a by-product removal device (500) provided between the polymerization reaction tank (400) and the polymer supply unit (600), the by-product removal device (500) removing by-products generated together with the polymer by the polymerization reaction in the polymerization reaction tank (400).

Description

Technical Field

[0001] The present invention relates to a chemical recovery device and the like. Background Art

[0002] Patent Document 1 discloses a method for recycling PET (polyethylene terephthalate) bottles by crushing the PET bottles to produce PET sheets that are raw materials for new PET bottles. Specifically, mechanical recycling is known in which the crushed PET bottles are heated and melted and then solid-phase polymerized to obtain PET sheets, and chemical recycling is known in which the crushed PET bottles are decomposed into intermediates or depolymerized products such as bis(2-hydroxyethyl)terephthalate (BHET) by depolymerization reaction and then repolymerized to obtain PET sheets.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-153176

[0006] Patent Document 2: Japanese Patent Application Publication No. 2022-27158 Summary of the invention

[0007] Problems to be solved by the invention

[0008] When manufacturing PET sheets and PET pellets as described above (hereinafter referred to as sheets and pellets, including sheets and pellets that are not made of PET as raw materials), it is necessary to cool the molten PET into sheets and pellets. In addition, when manufacturing new PET bottles, etc. from the sheets and pellets, it is necessary to heat and melt the sheets and pellets and then supply them to a molding machine such as an injection molding machine. The cooling of such sheets and pellets during the manufacture and the heating of the sheets and pellets during the manufacture of new PET bottles, etc. are essentially opposite thermal processes. Since there are cooling and heating processes related to the sheets and pellets that have no substantial significance from the perspective of recycling PET bottles, etc. into PET bottles, it can also be regarded as a waste of energy in the recycling process aimed at saving resources and energy.

[0009] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a chemical recovery device or the like capable of recovering molded products such as PET bottles using less energy than conventional methods.

[0010] Means for solving technical problems

[0011] In order to solve the above-mentioned problems, a chemical recovery device according to one embodiment of the present invention comprises: a depolymerization reaction tank for decomposing a first molded product composed of a polymer into a depolymerized product through a depolymerization reaction; a polymerization reaction tank for synthesizing the depolymerized product into a polymer through a polymerization reaction; and a polymer supply unit for supplying the polymer synthesized in the polymerization reaction tank to a molding machine for molding a second molded product.

[0012] In this embodiment, the polymer synthesized in the polymerization reaction tank is not made into sheets or pellets, but is directly supplied to the molding machine through the polymer supply unit. Since the cooling process and heating process related to the sheets or pellets as in the past are not required, the molded products such as PET bottles can be recovered with less energy than in the past.

[0013] Another embodiment of the present invention is also a chemical recovery device, which includes: a polymerization reaction tank, which synthesizes a polymer by polymerization reaction of a depolymerized product decomposed by a depolymerization reaction of a first molded product composed of a polymer; and a polymer supply unit, which supplies the polymer synthesized in the polymerization reaction tank to a molding machine for molding a second molded product.

[0014] Another embodiment of the present invention is also a chemical recovery device having a polymer supply unit that supplies a polymer synthesized by a polymerization reaction of a depolymerized product obtained by decomposing a first molded product composed of a polymer through a depolymerization reaction to a molding machine that molds a second molded product.

[0015] Another embodiment of the present invention is a chemical recycling molding system. The chemical recycling molding system comprises: a depolymerization reaction tank, which decomposes a first molded product composed of a polymer into a depolymerized product through a depolymerization reaction; a polymerization reaction tank, which synthesizes the depolymerized product into a polymer through a polymerization reaction; and a molding machine, which molds the polymer synthesized in the polymerization reaction tank into a second molded product.

[0016] In addition, any combination of the above-mentioned constituent elements, and expressions thereof converted into methods, apparatuses, systems, recording media, computer programs, etc. are also included in the present invention.

[0017] Effects of the Invention

[0018] According to the present invention, molded products such as PET bottles can be recycled using less energy than before. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The structure of the chemical recovery molding system according to the first embodiment is schematically shown.

[0020] Figure 2 Schematic representation of the polymerization and depolymerization reactions of PET.

[0021] Figure 3 A modified example of the by-product removal device is shown.

[0022] Figure 4 The structure of the chemical recovery molding system according to the second embodiment is schematically shown.

[0023] Figure 5 The structure of the chemical recovery molding system involved in the third embodiment is schematically shown.

[0024] Figure 6 The depolymerization reaction is schematically represented.

[0025] Figure 7 The structure of the chemical recovery molding system involved in the third embodiment is schematically shown.

[0026] Figure 8 A first embodiment of the mechanical mixing section is schematically shown.

[0027] Fig. 9 A first embodiment of the mechanical mixing section is schematically shown.

[0028] Fig.10 A second embodiment of the mechanical mixing section is schematically shown.

[0029] Fig.11 A second embodiment of the mechanical mixing section is schematically shown.

[0030] Fig.12 A third embodiment of the mechanical mixing section is schematically shown.

[0031] Fig.13 A third embodiment of the mechanical mixing section is schematically shown.

[0032] Fig.14 A first variation of the chemical recovery molding system is shown.

[0033] Fig.15 A second variant of the chemical recovery molding system is shown. DETAILED DESCRIPTION

[0034] Hereinafter, the method for implementing the present invention (hereinafter also referred to as an embodiment) is described in detail with reference to the accompanying drawings. In the description and / or the accompanying drawings, the same or equivalent constituent elements, parts, processes, etc. are marked with the same symbols, and repeated descriptions are omitted. The scales and shapes of the various parts shown in the figures are appropriately set to simplify the description, and no restrictive interpretation is made unless otherwise specified. The embodiments are examples and do not limit the scope of the present invention in any way. All the features described in the embodiments and their combinations are not necessarily the essence of the present invention.

[0035] Figure 1The structure of the chemical recovery molding system according to the first embodiment of the present invention is schematically shown. The chemical recovery molding system includes a chemical recovery device 100 and an injection molding machine 1. The chemical recovery device 100 includes a polymer adjustment device 200, a depolymerization reaction tank 300, a polymerization reaction tank 400, a by-product removal device 500, and a polymer supply unit 600. The injection molding machine 1 ( Figure 1 2 are schematically shown in the figure), the polymer adjustment device 200, the depolymerization reaction tank 300, the polymerization reaction tank 400, the by-product removal device 500 and the polymer supply unit 600 are set in any number. In particular, typically, by making the number of the injection molding machine 1 and the polymerization reaction tank 400, which have a slower processing speed and reaction speed than other processing units, larger than the other processing units, the processing performance can be improved so that these processing units do not become a serious bottleneck.

[0036] The polymer adjustment device 200 adjusts the polymer such as PET constituting the first molded product such as a PET bottle for the depolymerization reaction tank 300 in the later stage. Specifically, the polymer adjustment device 200 performs processes such as crushing, heating and melting, mixing, etc. on the first molded product such as a PET bottle to adjust the polymer such as PET to a state (phase, shape, size, etc.) suitable for the depolymerization reaction in the depolymerization reaction tank 300. In addition, the first molded product may be any molded product other than a bottle, such as a sheet, a film, or a fiber. Furthermore, the polymer constituting the first molded product may be any polymer other than PET, such as polyester (including PET), polyamide, or polyurethane.

[0037] The depolymerization reaction tank 300 decomposes the polymer such as PET adjusted by the polymer adjustment device 200 into depolymerized products through a depolymerization reaction. When the polymer supplied from the polymer adjustment device 200 is PET, an intermediate BHET is obtained as a depolymerized product through a depolymerization reaction in the depolymerization reaction tank 300. In addition, the depolymerized product obtained in the depolymerization reaction tank 300 may include monomers of the polymer. When the polymer is PET, the monomers are, for example, ethylene glycol, terephthalic acid, dimethyl terephthalate, and ethylene terephthalate.

[0038] like Figure 2 As schematically shown, in the depolymerization reaction (300) of PET as a polymer, the depolymerization material supply unit 310 ( Figure 1 ) is supplied to the depolymerization reaction tank 300 as a depolymerization material to decompose PET, thereby obtaining BHET as a depolymerized product. In addition, EG may be supplied to the polymer adjustment device 200 instead of being supplied to the depolymerization material supply unit 310, or may be supplied to the polymer adjustment device 200 in addition to being supplied to the depolymerization material supply unit 310. In order to promote the depolymerization reaction, a heater 320 ( Figure 1) or a heat insulator to maintain the temperature in the depolymerization reaction tank 300 at a temperature suitable for the depolymerization reaction. Figure 2 The temperature suitable for the depolymerization reaction of PET to BHET is between 220°C and 250°C, preferably between 230°C and 245°C, more preferably between 235°C and 240°C. And, Figure 2 The pressure suitable for the depolymerization reaction of PET to BHET is between 0.3 MPa and 0.8 MPa, preferably between 0.4 MPa and 0.6 MPa, and more preferably between 0.45 MPa and 0.55 MPa. The pressure in the depolymerization reaction tank 300 is adjusted by a pump (not shown) attached to the depolymerization reaction tank 300.

[0039] Since the viscosity of the fluid in the depolymerization reaction tank 300 that produces BHET having a smaller molecular weight than PET as a polymer is lower than the viscosity of the fluid in the polymerization reaction tank 400 described later that produces PET having a larger molecular weight, a low-viscosity stirring blade is used as the stirring blade 330 for stirring the fluid in the depolymerization reaction tank 300 to promote the depolymerization reaction. Examples of the low-viscosity stirring blade 330 include a propeller blade, a disk turbine blade, and a paddle blade.

[0040] At the rear section of the depolymerization reaction tank 300, there are provided impurity removal devices 340, 350, and 360 for removing impurities from the fluid containing BHET as a depolymerized product as a main component. The foreign resin removal device 340 removes resins different from the target resin such as PET and / or their depolymerized products by the principle of floating separation and sedimentation removal. The coloring matter removal device 350 removes coloring matter by activated carbon or the like. The metal ion removal device 360 ​​removes metal ions by the principle of ion exchange or the like. At the rear section of the impurity removal devices 340, 350, and 360, there is provided a buffer tank 370 for temporarily storing the fluid containing BHET or the like as a main component after impurities have been removed before supplying it to the polymerization reaction tank 400.

[0041] The buffer tank 370 may be provided with a first preheater 371 for heating or keeping the depolymerized product (fluid containing BHET or the like as a main component) warm before being supplied to the polymerization reaction tank 400 at the subsequent stage. The first preheater 371 may maintain the depolymerized product at the same temperature (between 220° C. and 250° C.) as that of the heater 320 attached to the depolymerization reaction tank 300, or may maintain the depolymerized product at the same temperature (between 250° C. and 300° C.) as that of the heater 410 attached to the polymerization reaction tank 400 described later. In this way, by providing the buffer tank 370 having a preheating mechanism (first preheater 371) at the upstream stage of the polymerization reaction tank 400 as needed, the depolymerized product to be supplied to the polymerization reaction tank 400, which typically has a slower processing speed or reaction speed than the depolymerization reaction tank 300, the byproduct removal device 500 described later, and other processing parts, can be stored in a state of being kept at an appropriate temperature. As a result, the overall capacity of the chemical recovery device 100 can be increased, and the chemical recovery device 100 can be operated stably and continuously while supplying appropriate amounts of reactants to each processing unit such as the depolymerization reaction tank 300, the polymerization reaction tank 400, the byproduct removal device 500, and the polymer supply unit 600 at an appropriate time (without causing the so-called "resin supply failure"). In addition, the preheating mechanism such as the first preheater 371 is not limited to the buffer tank 370, and can be installed in any position between the depolymerization reaction tank 300 and the polymerization reaction tank 400 (for example, the impurity removal devices 340, 350, 360) in any manner.

[0042] The polymerization reaction tank 400 synthesizes the depolymerized products such as BHET generated in the depolymerization reaction tank 300 and from which impurities have been removed by the impurity removal devices 340, 350, and 360 into polymers through polymerization reactions. When the depolymerized products generated in the depolymerization reaction tank 300 are BHET, the polymer PET can be obtained again through the polymerization reaction in the polymerization reaction tank 400.

[0043] like Figure 2 As schematically shown, in the polymerization reaction (400) of BHET as a depolymerized product, EG is generated as a byproduct together with PET as a polymer, i.e., a main product. This EG can be refluxed to the depolymerization material supply unit 310 and utilized in the depolymerization reaction of PET in the depolymerization reaction tank 300. Since the EG generated in the polymerization reaction tank 400 is not wasted but can be reused on site (depolymerization reaction tank 300), the operation efficiency of the chemical recovery device 100 can be improved. In particular, since the purchase amount of EG used for the depolymerization reaction of PET in the depolymerization reaction tank 300 can be significantly reduced, the operation cost of the chemical recovery device 100 can be reduced.

[0044] In order to promote the above-mentioned polymerization reaction, a heater 410 ( Figure 1) or a heat insulator to maintain the polymerization reaction tank 400 at a temperature suitable for the polymerization reaction. Figure 2 The temperature suitable for the polymerization reaction of BHET to PET is between 250°C and 300°C, preferably between 260°C and 290°C, and more preferably between 270°C and 280°C. Here, the polymerization heating temperature based on the heater 410 attached to the polymerization reaction tank 400 is higher than the depolymerization heating temperature based on the heater 320 attached to the depolymerization reaction tank 300. PET with a larger molecular weight and a higher melting point is generated in the polymerization reaction tank 400, but by maintaining the temperature higher than that of the depolymerization reaction tank 300 where BHET with a smaller molecular weight and a lower melting point is generated, the main product PET of the polymerization reaction tank 400 is maintained in a molten state. In addition, Figure 2 The polymerization reaction of BHET to PET is preferably carried out in a vacuum state. Therefore, a vacuum pump (not shown) is provided in the polymerization reaction tank 400.

[0045] Since the fluid viscosity in the polymerization reaction tank 400 that produces PET having a larger molecular weight is higher than the fluid viscosity in the depolymerization reaction tank 300 that produces BHET having a smaller molecular weight than the polymer PET, a high-viscosity stirring blade is used as the stirring blade 420 for stirring the fluid in the polymerization reaction tank 400 to promote the polymerization reaction. Examples of the high-viscosity stirring blade 420 include an anchor blade and a helical ribbon blade.

[0046] As a numerical value associated with the degree of polymerization of a polymer such as PET, IV (Intrinsic viscosity) value or intrinsic viscosity is known. The IV value (dL / g) is also used as an indicator of the use of the polymer. In PET, if the IV value is about 0.72 or more, it can be used for bottles, if the IV value is about 0.65 or more, it can be used for sheets, films, etc., and if the IV value is about 0.58 or more, it can be used for fibers. In this embodiment, the purpose is to finally obtain PET with an IV value that can be used for bottles and sheets. As described later, since the IV value also becomes higher in the by-product removal device 500 at the rear stage of the polymerization reaction tank 400, the IV value of the PET synthesized in the polymerization reaction tank 400 can be relatively low. Specifically, the IV value of the PET synthesized in the polymerization reaction tank 400 is between 0.2 and 0.7, preferably between 0.3 and 0.7, and more preferably between 0.3 and 0.55.

[0047] A buffer tank 430 for temporarily storing the polymer synthesized in the polymerization reaction tank 400 before supplying to the by-product removal device 500 and / or the polymer supply unit 600 at the subsequent stage may be provided at the subsequent stage. A second preheater 431 for heating or keeping the polymer warm before supplying to the by-product removal device 500 and / or the polymer supply unit 600 at the subsequent stage may be provided in the buffer tank 430. The second preheater 431 may maintain the polymer at the same temperature (between 250° C. and 300° C.) as the heater 410 attached to the polymerization reaction tank 400, or at the same temperature (between 250° C. and 290° C.) suitable for polymerization reaction as the heater 520 attached to the later-described by-product removal device 500, or at the same temperature (between 250° C. and 290° C.) as the heater 620 attached to the later-described polymer supply unit 600.

[0048] Thus, by installing the buffer tank 430 having a preheating mechanism (second preheater 431) at the front stage of the byproduct removal device 500 and / or the polymer supply unit 600 as needed, the polymer to be fed to the byproduct removal device 500 and / or the polymer supply unit 600 can be stored in a state of being kept at an appropriate temperature. As a result, the capacity of the chemical recovery device 100 as a whole can be increased, and the chemical recovery device 100 can be operated stably and continuously while supplying an appropriate amount of reactants to each processing unit such as the depolymerization reaction tank 300, the polymerization reaction tank 400, the byproduct removal device 500, and the polymer supply unit 600 in a timely manner (without causing the so-called "resin supply cut-off"). In addition, the preheating mechanism such as the second preheater 431 is not limited to the buffer tank 430, and can be installed in any manner at any position between the polymerization reaction tank 400 and the byproduct removal device 500 and / or any position between the byproduct removal device 500 and the polymer supply unit 600.

[0049] A by-product removal device 500 is provided at the rear section of the polymerization reaction tank 400 (and at the front section of the polymer supply unit 600 described later) for passing PET (main product) and EG (by-product) generated by the polymerization reaction in the polymerization reaction tank 400 to remove EG as a by-product. The by-product removal device 500 shown in the figure includes a plurality of linear members 510 extending from the top to the bottom. Due to the increased surface area due to the plurality of linear members 510, the volatilization of EG attached to the surface of each linear member 510 is promoted, and EG is effectively separated and removed from the high-viscosity PET.

[0050] This EG can be returned to the depolymerization material supply unit 310 and utilized in the depolymerization reaction of PET in the depolymerization reaction tank 300. Since the EG separated and removed in the by-product removal device 500 is not wasted but can be reused on site (depolymerization reaction tank 300), the operation efficiency of the chemical recovery device 100 can be improved. In particular, since the purchase amount of EG used for the depolymerization reaction of PET in the depolymerization reaction tank 300 can be significantly reduced, the operation cost of the chemical recovery device 100 is reduced.

[0051] Furthermore, since PET with a relatively low degree of polymerization (i.e., IV value) is attached to the surface of each linear member 510, and unreacted BHET is also attached in the polymerization reaction tank 400, the same polymerization reaction as in the polymerization reaction tank 400 can be effectively performed through a large surface area. Therefore, the IV value of PET as the main product becomes high after passing through the by-product removal device 500. Specifically, the IV value of PET after passing through the by-product removal device 500 is 0.7 or more, preferably 0.8 or more, and more preferably 0.85 or more.

[0052] In order to promote the polymerization reaction, a heater 520 ( Figure 1 ) or a heat insulator is used to maintain a temperature suitable for the polymerization reaction in the by-product removal device 500. Specifically, the heating temperature by the heater 520 is between 250°C and 290°C, preferably between 260°C and 280°C. Here, the heating temperature by the heater 520 attached to the by-product removal device 500 is preferably higher than the polymerization heating temperature by the heater 410 attached to the polymerization reaction tank 400. In the by-product removal device 500, the polymerization reaction progresses more than in the polymerization reaction tank 400, and as a result, the molecular weight of PET as a polymer becomes larger and the melting point becomes higher. Therefore, by maintaining the temperature in the by-product removal device 500 higher than that in the polymerization reaction tank 400, the PET as a product of the by-product removal device 500 can be maintained in a molten state. In addition, a heater or a heat insulator as a second heater that heats or keeps the temperature at least to the polymerization heating temperature by the heater 410 attached to the polymerization reaction tank 400 may be provided around the piping between the polymerization reaction tank 400 and the by-product removal device 500. In addition, similar to the polymerization reaction in the polymerization reaction tank 400, the polymerization reaction in the by-product removal device 500 is preferably carried out in a vacuum state. Therefore, a vacuum pump (not shown) is provided in the by-product removal device 500. By making the by-product removal device 500 in a vacuum state (decompression state), EG as a by-product can be effectively removed.

[0053] In addition, the structure of the by-product removal device 500 is not limited to Figure 1 For example, you can Figure 3 The "horizontal double-shaft" stirring device shown is used as the by-product removal device 500. The stirring device has a vertical axis. Figure 3 The two stirring blades rotate around the two rotating shafts to stir the PET and EG as stirring objects. The two stirring blades promote the volatilization of EG, so that EG can be effectively separated and removed from the high-viscosity PET. In addition, Figure 3 The details of the stirring device are disclosed in Japanese Patent No. 2925599 which is incorporated herein by reference.

[0054] The polymer supply unit 600 supplies the polymer such as PET synthesized in the polymerization reaction tank 400 (or the polymerization reaction tank 400 and the by-product removal device 500) to the injection molding machine 1 for molding the second molded product such as the PET bottle. The polymer supply unit 600 is equipped with a delivery pump 610 such as a gear pump or a screw pump, and the delivery pump 610 is suitable for supplying the high-purity and high-viscosity (i.e., high degree of polymerization or high IV value) PET from which the EG as a by-product in the by-product removal device 500 is removed to the injection molding machine 1 in a molten state.

[0055] The polymer supply unit 600 is provided with a heater 620 or a heat retainer as a first heater for heating or retaining the polymer such as PET delivered to the injection molding machine 1 by the delivery pump 610 to maintain it in a molten state. Specifically, the heating temperature by the heater 620 is between 250° C. and 290° C., preferably between 260° C. and 280° C. Here, the heating temperature (first heating temperature) by the heater 620 (first heater) provided in the polymer supply unit 600 is preferably higher than the second heating temperature by the second heater such as the heater 410 attached to the polymerization reaction tank 400, the heater 520 attached to the by-product removal device 500, or a heater (not shown) provided between the polymerization reaction tank 400 and the by-product removal device 500. The polymerization reaction started in the polymerization reaction tank 400 gradually proceeds and is completed in the by-product removal device 500. As a result, the molecular weight of PET or the like as a polymer in the polymer supply section 600 becomes larger and the melting point becomes higher than that in the polymerization reaction tank 400 and the by-product removal device 500. Therefore, by setting the first heating temperature in the polymer supply section 600 higher than the previous second heating temperature, a polymer such as PET with high viscosity (i.e., high polymerization degree or high IV value) and high melting point can be maintained in a molten state. In addition, a vacuum pump or the like (not shown) may be attached to the polymer supply section 600. By making the inside of the polymer supply section 600 a vacuum state (decompression state), the polymerization degree can also be increased in the polymer supply section 600.

[0056] A temperature gradient may be provided so that the heating temperature gradually increases from the polymerization reaction tank 400 to the polymer supply unit 600. For example, by increasing the heating temperature of a heater (not shown) provided between the polymerization reaction tank 400 and the by-product removal device 500 compared to the heating temperature of the heater 410 provided in the polymerization reaction tank 400, increasing the heating temperature of a heater 520 provided in the by-product removal device 500 compared to the heating temperature of the heater (not shown), and increasing the heating temperature of a heater 620 provided in the polymer supply unit 600 compared to the heating temperature of the heater 520, it is possible to reliably maintain a polymer such as PET having a high melting point in a molten state from the polymerization reaction tank 400 to the polymer supply unit 600. In addition, a heater that heats or keeps a polymer such as PET warm to maintain it in a molten state may be provided between the polymer supply unit 600 and the injection molding machine 1.

[0057] The injection molding machine 1 molds the polymer such as PET in a molten state generated in the chemical recovery device 100 into a second molded product. The second molded product may be of the same type or different type as the first molded product that has been subjected to a treatment such as pulverization in the polymer adjustment device 200. For example, both the first molded product and the second molded product may be PET bottles. In addition, one of the first molded product and the second molded product may be a PET bottle, and the other may be a molded product other than a bottle such as a sheet, a film, or a fiber. Generally, in mechanical recovery, the IV value of the second molded product after recovery will be lower than the IV value of the first molded product before recovery, but according to the chemical recovery device 100 involved in this embodiment that is equipped with an impurity removal device 340, 350, 360, a byproduct removal device 500, etc. to increase the IV value, the IV value of the second molded product after recovery can be made higher than the IV value of the first molded product before recovery. For example, according to this embodiment, it is also possible to recover a PET fiber with a low IV value as the first molded product and make a PET bottle with a high IV value as the second molded product.

[0058] The injection molding machine 1 molds a molten resin such as PET into a second molded product. An injection molding machine using molten resin as a raw material is disclosed in, for example, Patent Document 2. This application incorporates by reference the entire contents of the document (Japanese Patent Application No. 2020-130985) filed on July 31, 2020. Figure 1 As schematically shown, a plurality of injection molding machines 1 may be installed in parallel. The molding machine to which the molten resin and the like are supplied from the chemical recovery device 100 is not limited to an injection molding machine, but may be any molding machine (eg, a compression molding machine).

[0059] In the present embodiment described above, the polymer resynthesized in the polymerization reaction tank 400 is not made into sheets or pellets, but is directly supplied to the injection molding machine 1 through the polymer supply unit 600. Since the cooling process and heating process related to the sheets or pellets as in the past are not required, the molded products such as PET bottles can be recovered with less energy than in the past.

[0060] In the chemical recovery device 100 of this embodiment, since the polymer resynthesized in the polymerization reaction tank 400 is directly supplied to the injection molding machine 1, it is necessary to quickly achieve the IV value of the polymer required for its molded product (second molded product). In this embodiment, in addition to the polymerization reaction tank 400, a byproduct removal device 500 having a function of promoting the polymerization reaction and increasing the IV value of the polymer is provided, so that this requirement can be fully met.

[0061] Figure 4 The structure of the chemical recovery molding system according to the second embodiment of the present invention is schematically shown. Figure 1 The same components are marked with the same reference numerals, and repeated descriptions are omitted. In the present embodiment, a polymer return section 900 is provided to return at least a portion of the polymer synthesized in the polymerization reaction tank 400 to the polymerization reaction tank 400 and / or the depolymerization reaction tank 300. The polymer return section 900 in the example shown is provided between the by-product removal device 500 and the polymer supply section 600, but is not limited thereto. The polymer return section 900 may be provided at any position between the by-product removal device 500 and the injection molding machine 1. For example, the polymer return section 900 may also be provided between the polymer supply section 600 and the injection molding machine 1.

[0062] The polymer return section 900 returns at least a portion of the polymer synthesized in the polymerization reaction tank 400 (in the illustrated example, the polymer from which byproducts have been further removed by the byproduct removal device 500) to the polymerization reaction tank 400 and / or the depolymerization reaction tank 300 instead of sending it to the polymer supply section 600. For example, the polymer return section 900 may supply the polymer to the buffer tank 370 provided at the upstream of the polymerization reaction tank 400 to return the polymer to the polymerization reaction tank 400, or may supply the polymer to the polymer adjustment device 200 provided at the upstream of the depolymerization reaction tank 300 to return the polymer to the depolymerization reaction tank 300.

[0063] The main purpose of the polymer return section 900 is to cope with the mismatch between the operation time and capacity of the chemical recovery device 100 and the injection molding machine 1. For example, the chemical recovery device 100 typically operates continuously (continuous operation), and the injection molding machine 1 typically operates intermittently (intermittent operation). Therefore, especially during the period when the injection molding machine 1 is stopped due to maintenance of the mold, etc., the injection molding machine 1 cannot receive all the polymers from the polymer supply section 600 (unacceptable period). In order to keep the chemical recovery device 100 running continuously during such an unacceptable period without wasting the remaining polymer that cannot be received by the injection molding machine 1, the remaining polymer is returned to the polymerization reaction tank 400 and / or the depolymerization reaction tank 300 in a molten state. In this way, since there is no need to make the excess polymer in a molten state that cannot be received by the injection molding machine 1 into sheets or pellets by cooling or heat dissipation, energy waste can be reduced.

[0064] The polymer return unit 900 can change the return destination (polymerization reaction tank 400 and / or depolymerization reaction tank 300) and the return ratio of the surplus polymer according to the length of the unacceptable period. For example, before the unacceptable period exceeds a predetermined period threshold, more polymer can be returned to the polymerization reaction tank 400 than to the depolymerization reaction tank 300, and after the unacceptable period exceeds the period threshold, more polymer can be returned to the depolymerization reaction tank 300 than to the polymerization reaction tank 400.

[0065] It can be considered that as long as the unacceptable period is short and does not exceed the period threshold, even if the molten polymer is kept at a high temperature (for example, between 270° C. and 280° C. as described above) and circulated in the polymerization reaction tank 400 (and the byproduct removal device 500), the polymer will not deteriorate or the IV value will not rise excessively. Therefore, for a short unacceptable period, the polymer return unit 900 preferably returns most of the remaining polymer (for example, 100%, 80%, 60%) to the polymerization reaction tank 400 (buffer tank 370).

[0066] On the other hand, if the unacceptable period exceeds the period threshold and becomes a long period, the polymer may be degraded or the IV value may be excessively increased due to the thermal process generated by the molten polymer circulating in the polymerization reaction tank 400 (and the byproduct removal device 500) while maintaining a high temperature (for example, between 270°C and 280°C as described above). Therefore, for a long unacceptable period, the polymer return unit 900 preferably returns most of the remaining polymer (for example, 100%, 80%, 60%) to the depolymerization reaction tank 300 (polymer adjustment device 200). By performing the depolymerization reaction again in the depolymerization reaction tank 300, the above thermal process is substantially reset, so that the polymer supplied to the injection molding machine 1 by the polymer supply unit 600 after the unacceptable period can be effectively prevented from being degraded or the IV value excessively increased.

[0067] In the present embodiment, since the temperature of the molten polymer in the circulation is approximately fixed (for example, between 270° C. and 280° C. as described above), the length of the unacceptable period indicates the thermal history. On the other hand, when the temperature of the molten polymer in the circulation can vary significantly, the thermal history can be strictly grasped by monitoring the temperature in addition to the length of the unacceptable period. At this time, the polymer return unit 900 can return more polymer to the polymerization reaction tank 400 than to the depolymerization reaction tank 300 before the thermal history exceeds the prescribed thermal history threshold, and return more polymer to the depolymerization reaction tank 300 than to the polymerization reaction tank 400 after the thermal history exceeds the thermal history threshold.

[0068] In addition, the polymer return section 900 can change the return destination (polymerization reaction tank 400 and / or depolymerization reaction tank 300) and the return ratio according to the physical property values ​​such as the IV value of the polymer to be returned. For example, when the IV value is within a predetermined allowable range, more polymer than the depolymerization reaction tank 300 can be returned to the polymerization reaction tank 400, and when the IV value is outside the allowable range (specifically, when it is greater than the upper limit of the allowable range), more polymer than the polymerization reaction tank 400 can be returned to the depolymerization reaction tank 300. In the latter case, the excessively increased IV value is reduced to the allowable range by performing the depolymerization reaction again in the depolymerization reaction tank 300.

[0069] Furthermore, the polymer return unit 900 may gradually change the return ratio to the polymerization reaction tank 400 and the depolymerization reaction tank 300 according to the length of the unreceivable period and the physical property values ​​such as the IV value of the polymer to be returned. For example, the return ratio to the depolymerization reaction tank 300 may be gradually increased as the unreceivable period becomes longer, or the return ratio to the depolymerization reaction tank 300 may be gradually increased as the IV value increases.

[0070] Figure 5The structure of the chemical recovery molding system according to the third embodiment of the present invention is schematically shown. The same reference numerals are used for the same components as those in the above embodiment, and repeated descriptions are omitted. Figure 5 In the same figures and the subsequent figures, for the sake of convenience, the main components of the chemical recycling molding system are represented as functional blocks. In this embodiment, a mechanical mixing unit 380 is provided in the depolymerization reaction tank 300, and the mechanical mixing unit 380 mechanically or physically mixes the depolymerization material and the polymer at least in the early stage of the depolymerization reaction in which the polymer is decomposed into depolymerized products by the depolymerization material.

[0071] like Figure 2 As shown in Figure 2, the depolymerization reaction of polymers such as PET into depolymers such as BHET by depolymerizing materials such as EG is essentially a chemical process. Figure 6 As schematically shown, in the early or early stages of the depolymerization reaction when the degree of polymerization of the polymer is high, the polymer such as PET may exist as relatively large masses such as sheets or pellets, and mechanical action such as stirring or mixing is dominant over chemical action (chemical reaction). On the other hand, in the late stages of the depolymerization reaction, the desired chemical action (chemical reaction) is dominant.

[0072] The mechanical mixing section 380 involved in this embodiment can effectively promote the period by mechanically mixing the depolymerization materials such as EG and the polymers such as PET, especially in the early stage or early stage of the depolymerization reaction dominated by mechanical action, and can quickly transition to the later stage where the desired chemical action (chemical reaction) is dominant. As a result, the depolymerization reaction in the depolymerization reaction tank 300 can be effectively promoted in a short time. The mechanical mixing section 380 can continue to mechanically mix the depolymerization materials such as EG and the polymers such as PET not only in the early stage or early stage of the depolymerization reaction dominated by mechanical action, but also in the later stage of the depolymerization reaction dominated by chemical action (chemical reaction). In addition, the mechanical mixing section 380 can be responsible for the treatment of crushing, heating, melting, mixing, etc., similar to the above-mentioned polymer adjustment device 200. Therefore, the polymer adjustment device 200 may not be provided, and the polymer adjustment device 200 may be merged into the mechanical mixing section 380.

[0073] The mechanical mixing unit 380 described above may also be attached or externally mounted Figure 1 , Figure 4 For example, an ultrasonic device as described below as the mechanical mixing unit 380 may be installed on the outer wall surface and / or the inner wall surface of the depolymerization reaction tank 300, or a cavitation device as described below as the mechanical mixing unit 380 may be installed in the front section of the depolymerization reaction tank 300 (for example, on the supply path of the depolymerization material supply unit 310 supplying the depolymerization material such as EG to the depolymerization reaction tank 300).

[0074] Or, if Figure 7 As schematically shown, the depolymerization reaction tank 300 may be a multi-tank (or double-tank) structure including a first depolymerization reaction tank 301 at the front and a second depolymerization reaction tank 302 at the rear, and the mechanical mixing unit 380 may be provided at least in the first depolymerization reaction tank 301. The first depolymerization reaction tank 301 at the front is mainly responsible for Figure 6 The mechanical action in the depolymerization reaction is shown schematically in the figure. By providing the mechanical mixing section 380 in the first depolymerization reaction tank 301, the depolymerization material such as EG and the polymer such as PET are mechanically mixed in the initial or early stage of the depolymerization reaction where the mechanical action is dominant, and the period is effectively promoted. The second depolymerization reaction tank 302 at the rear stage is mainly responsible for the Figure 6 The second depolymerization reaction tank 302 may also be connected to the following Figure 1 , Figure 4 The depolymerization reaction tank 300 shown is constructed in the same manner.

[0075] The mechanical mixing section 380 described above may be constructed in any manner as long as it can achieve the function of mechanically mixing the depolymerized material such as EG and the polymer such as PET in the (especially) early stage of the polymerization reaction. Figure 7 In the embodiment of the present invention, there are multiple non-limiting embodiments of the mechanical mixing section 380 disposed in the first depolymerization reaction tank 301.

[0076] Figure 8 The first embodiment of the mechanical mixing section 380 is schematically shown. In this embodiment, the first depolymerization reaction tank 301 is composed of a mixing tank 810, a polymer supply section 820, a depolymerization material supply section 830, a depolymerized product discharge section 840, a polymer extraction section 850, a stirring blade 870, and an ultrasonic device 381 as the first embodiment of the mechanical mixing section 380.

[0077] In the mixing tank 810, a partial depolymerization reaction of a polymer such as a PET sheet is carried out, especially Figure 6The above-mentioned initial or early mechanical mixing with depolymerization materials such as EG. The polymer supply unit 820 supplies polymers such as PET sheets into the mixing tank 810. The depolymerization material supply unit 830 provided at the bottom of the mixing tank 810 supplies depolymerization materials such as EG that decompose polymers such as PET into the mixing tank 810. The depolymerization material supply unit 830 can supply a cleaning liquid such as PET slurry remaining after the depolymerization reaction (especially mechanical mixing) to the mixing tank 810. The depolymerization product discharge unit 840 provided at the upper part of the mixing tank 810 discharges liquid depolymerization products such as BHET generated by the depolymerization reaction. Although not shown in the figure, the depolymerization products such as BHET discharged from the depolymerization product discharge unit 840 can be supplied to the impurity removal devices 340 to 360 together with the depolymerization products such as BHET discharged from the second depolymerization reaction tank 302. Furthermore, the depolymerization product discharge unit 840 is not limited to depolymerization products such as BHET, and can also discharge any liquid component in the mixing tank 810, for example, the above-mentioned cleaning liquid. The polymer extraction unit 850 extracts the PET slurry and the like remaining after the depolymerization reaction. The PET slurry and the like extracted from the polymer extraction unit 850 are sent to the second depolymerization reaction tank 302 at the subsequent stage, and undergo further depolymerization reaction (especially with respect to Figure 6 The above-mentioned later desired chemical reaction) decomposes into depolymers such as BHET.

[0078] The stirring blade 870 and / or the ultrasonic device 381 mechanically mix or stir the polymer such as PET supplied from the polymer supply unit 820 and the depolymerization material such as EG supplied from the depolymerization material supply unit 830 in the mixing tank 810, thereby promoting the mechanical mixing in the initial or early stage of the depolymerization reaction in the first depolymerization reaction tank 301. Through such mechanical mixing, not only the depolymerization reaction is effectively carried out, but also the PET sheet and the like are micronized into a slurry state. The micronized PET slurry can be taken out of the mixing tank 810 through the polymer extraction unit 850 composed of a filter screen and a valve, and sent to the second depolymerization reaction tank 302.

[0079] The ultrasonic device 381 is installed, for example, continuously (for example, in a ring shape) or intermittently at any position of the outer wall surface and / or the inner wall surface of the mixing tank 810. The ultrasonic wave (vibration) generated by the ultrasonic device 381 mechanically mixes the polymer such as PET and the depolymerization material such as EG in the mixing tank 810. In addition, in the case where it is difficult to install the ultrasonic device 381 on the wall surface of the mixing tank 810, another ultrasonic tank equipped with the ultrasonic device 381 can be connected to the mixing tank 810. At this time, the mechanical mixing based on the ultrasonic device 381 is performed in the ultrasonic tank, and the micronized PET and the like are taken out from the polymer extraction part 850 of the mixing tank 810.

[0080] Figure 8The structure of the first depolymerization reaction tank 301 can achieve the desired function (mainly mechanical mixing) by, for example, the following steps. First, as the first step, the polymer supply unit 820 supplies polymers such as PET sheets into the mixing tank 810, and the depolymerization material supply unit 830 supplies depolymerized products such as EG into the mixing tank 810. At this time, the mixing tank 810 is maintained with Figure 1 The same temperature (e.g., between 220°C and 250°C, preferably between 230°C and 245°C, more preferably between 235°C and 240°C) and pressure (e.g., between 0.3MPa and 0.8MPa, preferably between 0.4MPa and 0.6MPa, more preferably between 0.45MPa and 0.55MPa) as in the depolymerization reaction tank 300 in the mixing tank 810 are generated. Figure 1 The reaction in the depolymerization reaction tank 300 is substantially the same as the initial depolymerization reaction ( Figure 6 However, according to Figure 8 As described above, mechanical mixing is promoted particularly by the ultrasonic device 381. In addition, when the PET sheet is too large, stirring by the contact stirring blade 870 is difficult, but the non-contact ultrasonic device 381 enables effective mixing regardless of the size of the PET sheet.

[0081] After the mechanical mixing of the polymer such as the PET sheet is fully performed in the mixing tank 810 (i.e., after the first step), or during the mechanical mixing (i.e., at the same time as the first step), as the second step, the depolymerization liquid containing the depolymerization products such as BHET generated by the depolymerization reaction is discharged from the depolymerization product discharge part 840 provided at the upper part of the mixing tank 810. The depolymerization product discharge part 840 is composed of a filter screen and a valve that can discharge the liquid component all the time or intermittently. The liquid depolymerization material such as EG, the catalyst and / or the liquid depolymerization products such as BHET generated by the depolymerization reaction supplied from the depolymerization material supply part 830 are filled from the bottom of the mixing tank 810 to the position where the depolymerization product discharge part 840 is provided. In this way, the liquid level in the mixing tank 810 is formed at the position where the depolymerization product discharge part 840 is provided. The excess liquid component is discharged from the depolymerization product discharge part 840 composed of the filter screen and the valve. In addition, a plurality of depolymerization product discharge parts 840 may be provided at different heights. At this time, the depolymerization product discharge part 840 disposed at the highest position is responsible for preventing overflow to form the liquid level in the mixing tank 810, and the depolymerization product discharge part 840 disposed at a lower position discharges depolymerization products such as BHET from an intermediate height position.

[0082] After the polymers such as PET sheets and the depolymerized materials such as EG are fully mechanically mixed in the mixing tank 810 , the micronized and accumulated PET slurry is taken out from the polymer extraction section 850 provided at the bottom of the mixing tank 810 as the third step after the first step.

[0083] The first to third steps described above may be continuously performed by continuously supplying the polymer such as the PET sheet by the polymer supply unit 820 and supplying the depolymerized material such as EG by the depolymerized material supply unit 830 (continuous processing), or may be performed in accordance with a predetermined processing unit or batch of the polymer such as the PET sheet and the depolymerized material such as EG (batch processing). For example, in the continuous processing, at least one of supplying the polymer (PET sheet, etc.) from the polymer supply unit 820, supplying the depolymerized material from the depolymerized material supply unit 830, discharging the depolymerized material from the depolymerized material discharge unit 840, and extracting the polymer (PET slurry, etc.) from the polymer extraction unit 850 is continuously or intermittently performed while the ultrasonic device 381 continuously emits ultrasonic waves and / or the stirring blade 870 continuously rotates in the mixing tank 810.

[0084] exist Fig. 9 In the modified example, the first depolymerization reaction tank 301 is composed of a mixing tank 810, a polymer supply part 820, a depolymerization material supply part 830, a depolymerization product discharge part 840, a polymer extraction part 850, a stirring blade 870, a baffle 880 and an ultrasonic device 381 as a first embodiment of the mechanical mixing part 380.

[0085] In this modification, when the polymer such as the PET sheet is mechanically mixed by the stirring blade 870 and / or the ultrasonic device 381, it collides with the baffle plate 880, which is also called a baffle plate, and is effectively micronized into a slurry state.

[0086] Fig.10 The second embodiment of the mechanical mixing section 380 is schematically shown. In this embodiment, the first depolymerization reaction tank 301 is composed of a mixing tank 810, a polymer supply section 820, a depolymerization material supply section 830, a depolymerized product discharge section 840, a polymer extraction section 850, a stirring blade 870, and a cavitation device 382 as a second embodiment of the mechanical mixing section 380. Figure 8 The same components are denoted by the same reference numerals, and repeated description is omitted.

[0087] The stirring blade 870 and / or the cavitation device 382 promotes the mechanical mixing of the initial or early stage of the depolymerization reaction in the first depolymerization reaction tank 301 by mechanically mixing or stirring the polymer such as PET supplied from the polymer supply part 820 and the depolymerization material such as EG supplied from the depolymerization material supply part 830 in the mixing tank 810. Through this mechanical mixing, not only the depolymerization reaction is effectively carried out, but also the PET sheet and the like are micronized into a slurry state. The micronized PET slurry can be taken out of the mixing tank 810 through the polymer extraction part 850 composed of a filter screen and a valve and sent to the second depolymerization reaction tank 302.

[0088] The cavitation device 382 is provided, for example, on a supply path for supplying depolymerization materials such as EG from the depolymerization material supply section 830 to the mixing tank 810. The cavitation device 382 introduces a pressure difference into the depolymerization materials such as EG in a liquid state to cause cavitation (cavitation phenomenon) accompanied by the generation and disappearance of bubbles. The typical microbubbles generated with cavitation mechanically mix the polymers such as PET and the depolymerization materials such as EG in the mixing tank 810. In addition, when it is difficult to set the cavitation device 382 in the first depolymerization reaction tank 301, another cavitation tank equipped with the cavitation device 382 can be connected to the mixing tank 810. At this time, mechanical mixing based on the cavitation device 382 is performed in the cavitation tank, and the micronized PET and the like are taken out from the polymer extraction section 850 of the mixing tank 810. In addition, instead of the cavitation device 382 or in addition to the cavitation device 382, ​​a bubble generating device that generates microbubbles (also called microbubbles, microbubbles) based on a principle different from cavitation can be used as the mechanical mixing section 380.

[0089] according to Fig.10 In the first step for realizing the desired function (mainly mechanical mixing) of the first depolymerization reaction tank 301, the cavitation device 382 generates micro bubbles accompanied by cavitation in the depolymerization material such as EG supplied from the depolymerization material supply unit 830 to the mixing tank 810. These micro bubbles are introduced into the mixing tank 810 together with the depolymerization material such as EG, and the polymer such as the PET sheet supplied from the polymer supply unit 820 is mechanically mixed with the depolymerization material such as EG supplied from the depolymerization material supply unit 830. Figure 1 The reaction in the depolymerization reaction tank 300 is substantially the same as the initial depolymerization reaction ( Figure 6 However, according to Fig.10 As described above, mechanical mixing is promoted particularly by the cavitation device 382. In addition, when the PET sheet is too large, stirring by the contact stirring blade 870 is difficult, but the non-contact cavitation device 382 enables effective mixing regardless of the size of the PET sheet.

[0090] exist Fig.11 In the modified example, the first depolymerization reaction tank 301 is composed of a mixing tank 810, a polymer supply part 820, a depolymerization material supply part 830, a depolymerization product discharge part 840, a polymer extraction part 850, a stirring blade 870, a baffle 880 and a cavitation device 382 as a second embodiment of the mechanical mixing part 380.

[0091] In this modification, when the polymer such as the PET sheet is mechanically mixed by the stirring blade 870 and / or the cavitation device 382, ​​it collides with the baffle plate 880, which is also called a baffle plate, and is effectively finely divided into a slurry state.

[0092] Fig.12 A horizontal stirring device 383 is schematically shown as a third embodiment of the mechanical mixing unit 380. The horizontal stirring device 383 is composed of Figure 7 The first depolymerization reaction tank 301 in. And, Figure 7 The second depolymerization reaction tank 302 is Figure 1 , Figure 4 The depolymerization reaction tank 300 shown in the figure is a vertical stirring device. Here, "horizontal type" means stirring by a rotating body rotating around a rotation axis in a direction intersecting the vertical direction (for example, the horizontal direction), and "vertical type" means stirring by a rotating body (for example, a stirring blade) rotating around a rotation axis in a direction intersecting the horizontal direction (for example, the vertical direction).

[0093] exist Fig.12 (and later Fig.13 ), a three-dimensional coordinate system based on the X-axis, Y-axis, and Z-axis is set for convenience. For example, the X-axis and the Y-axis are horizontal directions, and the Z-axis is a vertical direction. The horizontal stirring device 383 in the example is long in the X direction.

[0094] The horizontal stirring device 383 includes a container 710 , a rotating body 720 , and a rotation driving unit 740 .

[0095] For example, from Figure 7The polymer adjustment device 200 in the embodiment supplies the polymer PM such as PET derived from the first molded article to the container 710 in a molten state. The container 710 includes: a polymer supply port 711 connected to the polymer adjustment device 200 to supply the polymer PM into the container 710; and a discharge port 712 to discharge the polymer PM (including unreacted depolymerization material and depolymerization products such as BHET as products) after being stirred (mechanically mixed) with the depolymerization material such as EG by the rotating body 720 described later to the outside of the container 710 and supply it to the second depolymerization reaction tank 302. The polymer supply port 711 can be connected to a delivery pump such as a gear pump or a screw pump that can adjust the supply amount and supply speed of the polymer PM into the container 710, and the discharge port 712 can be connected to a delivery pump such as a gear pump or a screw pump that can adjust the discharge amount and discharge speed of the polymer PM etc. to the outside of the container 710. In addition, a temperature control unit such as a heater that controls the inside of the container 710 at an appropriate temperature can be provided in the container 710 to maintain the molten state of the polymer PM.

[0096] like Fig.12 As shown, the container 710 is long in the X direction, for example, has a substantially rectangular YZ cross section (not shown). When the plurality of rotating bodies 720 are staggered in the Y direction, the YZ cross section of the container 710 becomes long in the Y direction (i.e., rectangular) in order to accommodate them.

[0097] exist Fig.12 In the embodiment, the polymer supply port 711 is provided at one end portion of the container 710 in the X direction ( Fig.12 The discharge port 712 is provided at the other end portion ( Fig.12 In the X-direction region between the polymer supply port 711 and the discharge port 712, one or more gas supply ports 713 for delivering a gas such as nitrogen to the gas phase in the container 710, and one or more depolymerization material supply ports 714 for supplying a depolymerization material such as EG to be mechanically mixed with the polymer PM to the gas phase in the container 710 are provided. In addition, in the X-direction region between the polymer supply port 711 and the discharge port 712, one or more rotating bodies 720 are provided to stir (mechanically mix) the molten polymer PM supplied from the polymer supply port 711 and the depolymerization material such as EG supplied from the depolymerization material supply port 714.

[0098] The rotating body 720 rotates in the container 710 to stir the polymer PM and the depolymerized material. Fig.12 In the example, the Z direction) crosses the direction (in Fig.12One or more rotating plates 721 rotate about a rotating axis 722 (in the example, the X direction is orthogonal to the Z direction). The rotating plate 721 is, for example, a circular plate having a circular YZ cross-section. However, the shape of the YZ cross-section of the rotating plate 721 is arbitrary, and can be, for example, a polygon such as an ellipse, a triangle, or a quadrilateral. The center or center of gravity of the rotating plate 721 on the YZ plane is preferably consistent with the center of the rotating axis 722. At this time, one or more rotating plates 721 and the rotating axis 722 are configured coaxially. In addition, the rotating body 720 can be provided with a screw instead of the rotating plate 721 or with a screw in addition to the rotating plate 721. When the rotating body 720 is provided with a screw, polymer PM such as PET can be supplied in a solid state.

[0099] exist Fig.12 In the example, the rotating body 720 has a plurality of rotating plates 721 separated in the axial direction (X direction) of the rotating shaft 722. The axial distance between two adjacent rotating plates 721 may be fixed or different as shown in the figure. When the stirring of the polymer PM and the depolymerization material is carried out and a part of it is decomposed into depolymers such as BHET, the viscosity or degree of polymerization of the polymer PM becomes lower. On the other hand, the closer to the inlet side of the container 710 (i.e., the polymer supply port 711 side), the higher the viscosity or degree of polymerization of the polymer PM, so the polymer PM becomes easier to adhere to the rotating plate 721. If the interval between the rotating plates 721 on the inlet side of such a container 710 is too small, the polymer PM attached to each rotating plate 721 interferes with each other and may hinder the stirring of the polymer PM (mechanical mixing with the depolymerization material) and the rotation of the rotating body 720. Therefore, it is preferred to reduce the interval between the rotating plates 721 from the polymer supply port 711 (front section) of the container 710 toward the discharge port 712 (rear section) as shown in the figure.

[0100] In this way, the polymer PM and the depolymerization material are effectively stirred or mixed in the rear section (discharge port 712 side) where the interval between the rotating plates 721 is small. Here, when a plurality of depolymerization material supply ports 714 are provided, the mechanical mixing efficiency of the polymer PM and the depolymerization material can be further improved by increasing the amount of the depolymerization material supplied from each depolymerization material supply port 714 from the front section toward the rear section.

[0101] The rotating body 720 is driven to rotate by a rotation driving unit 740 composed of a motor or the like. Specifically, the rotation driving unit 740 is connected to the rotation shaft 722 of the rotating body 720 and is driven to rotate. In this way, when the rotation shaft 722 is driven to rotate by the rotation driving unit 740, the plurality of rotating plates 721 fixed thereon rotate integrally. In addition, the polymer PM supplied from the polymer supply port 711 into the container 710 and toward the discharge port 712 is effectively mixed with the depolymerization material supplied from the depolymerization material supply port 714 into the container 710 by the rotating plurality of rotating plates 721.

[0102] By stirring by the rotating body 720, not only the polymer PM and the depolymerization material are mechanically mixed, but also the decomposition (chemical reaction) of BHET and the like into the depolymerization product is partially carried out. As a result, the IV value, viscosity, and polymerization degree of the polymer PM such as PET in the container 710 gradually decrease as it moves from the polymer supply port 711 toward the discharge port 712. In addition, the position or height of the polymer PM attached to each rotating plate 721 of the rotating body 720 indirectly indicates the IV value, viscosity, and polymerization degree of the polymer PM. Therefore, the highest arrival position of the polymer PM attached to the rotating plate 721 in the vertical direction (Z direction) can be detected by the unillustrated attachment position detection unit, thereby grasping the IV value, viscosity, and polymerization degree of the polymer PM. For example, the attachment position detection unit can detect the highest arrival position of the polymer PM attached to the rotating plate 721 in the vertical direction (Z direction) by light advancing in the direction (Y direction) intersecting the vertical direction (Z direction) and the rotation axis 722 (X direction).

[0103] The stirring mode adjustment unit (not shown) can adjust the stirring mode in the container 710 so that the attachment position (e.g., the highest reaching position) of the polymer PM detected by the attachment position detection unit deviates less from the desired position. The desired position here corresponds to the desired viscosity and polymerization degree of the polymer PM in the container 710. That is, the stirring mode adjustment unit can adjust the stirring mode in the container 710 so that the polymer PM in the container 710 reaches the desired viscosity and polymerization degree.

[0104] Specifically, the stirring mode adjustment unit can adjust, as a stirring mode in the container 710, at least one of the supply amount of the polymer PM and / or depolymerization material into the container 710, the supply speed of the polymer PM and / or depolymerization material into the container 710, the discharge amount to the outside of the container 710 through the discharge port 712, the discharge speed to the outside of the container 710 through the discharge port 712, the rotation speed of the rotating body 720, the pressure in the container 710 and the temperature in the container 710.

[0105] In addition to providing an attachment position detection unit that indirectly detects the degree of polymerization of the polymer PM, a polymerization degree estimation unit (not shown) that estimates the degree of polymerization of the polymer PM based on the attachment position of the polymer PM detected by the attachment position detection unit may be provided. In this case, the stirring mode adjustment unit adjusts the stirring mode in the container 710 so that the degree of polymerization of the polymer PM estimated by the polymerization degree estimation unit deviates less from the expected value.

[0106] Fig.13 A horizontal stirring device 384 is schematically shown as a fourth embodiment of the mechanical mixing section 380. Fig.12 The same components are marked with the same reference numerals, and repeated descriptions are omitted. Figure 7 The first depolymerization reaction tank 301 in. Fig.12 The horizontal stirring device 383 shown is a single tank type, and Fig.13 The horizontal stirring device 384 shown is a multi-trough type (a double-trough type in the example shown). Specifically, the horizontal stirring device 384 includes a first horizontal stirring device 384A at the front section or upstream side and a second horizontal stirring device 384B at the rear section or downstream side. The first horizontal stirring device 384A and the second horizontal stirring device 384B in the example shown are both long in the X direction.

[0107] The first horizontal stirring device 384A and the second horizontal stirring device 384B both include the above-mentioned container 710, the rotating body 720, and the rotation drive unit 740. The discharge port 712 of the first horizontal stirring device 384A is connected to the polymer supply port 711 of the second horizontal stirring device 384B.

[0108] The rotating body 720 in the first horizontal stirring device 384A and the second horizontal stirring device 384B is provided with a plurality of rotating plates 721 separated in the axial direction (X direction) of the rotating shaft 722. The axial distance between the adjacent rotating plates 721 in the first horizontal stirring device 384A is fixed, and the axial distance between the adjacent rotating plates 721 in the second horizontal stirring device 384B is fixed. Here, the fixed distance between the adjacent rotating plates 721 in the second horizontal stirring device 384B is preferably smaller than the fixed distance between the adjacent rotating plates 721 in the first horizontal stirring device 384A. In the second horizontal stirring device 384B in the later stage where the stirring of the polymer PM and the depolymerization material (and the decomposition of BHET etc. into the depolymerization product) has progressed, since the viscosity or polymerization degree of the polymer PM becomes lower, the distance between the rotating plates 721 can be made smaller than that of the first horizontal stirring device 384A.

[0109] Thus, the polymer PM and the depolymerization material are effectively stirred or mixed in the second horizontal stirring device 384B at the rear stage where the interval between the rotating plates 721 is small. Here, by increasing the amount of the depolymerization material supplied from the depolymerization material supply port 714 in the second horizontal stirring device 384B compared to the amount of the depolymerization material supplied from the depolymerization material supply port 714 in the first horizontal stirring device 384A, the efficiency of the mechanical mixing of the polymer PM and the depolymerization material can be further improved.

[0110] The present invention has been described above based on the embodiments. The combinations of the components and processes in the exemplified embodiments may have various variations, and it is obvious to those skilled in the art that such variations are within the scope of the present invention. Furthermore, the components of the above embodiments may be combined arbitrarily as long as their respective functions and effects are not completely impeded.

[0111] exist Figure 1 In the example of FIG. 1 , only one of each of the polymer adjustment device 200, the depolymerization reaction tank 300, the polymerization reaction tank 400, the byproduct removal device 500, and the polymer supply unit 600 is provided, but multiple of each may be provided. Such multiple processing units can perform the same processing in parallel, so the processing performance in the processing unit group can be improved. In addition, the difference in processing speed or reaction speed between the processing units can be reduced by increasing the number of slower processing units.

[0112] Furthermore, one or more processing units may receive materials from the preceding processing unit instead of or in addition to receiving materials from the preceding processing unit. Figure 1 The chemical recovery molding system shown can be supplied with external materials at different places or facilities. For example, when multiple polymerization reaction tanks 400 are provided, depolymers from the depolymerization reaction tank 300 can be supplied to a part of them, while depolymers prepared from the outside can be supplied to another part (the same as the depolymers supplied from the depolymer supply unit 300A described later). Similarly, when multiple by-product removal devices 500 and / or polymer supply units 600 are provided, polymers from the polymerization reaction tank 400 can be supplied to a part of them, while polymers prepared from the outside can be supplied to another part (the same as the polymers supplied from the polymer supply unit 400A described later). In this way, by allowing external materials to be received at each stage of the processing in the chemical recovery molding system, the flexibility of the chemical recovery molding system can be ensured and the efficient operation can be ensured.

[0113] Fig.14 The first modification of the chemical recovery molding system is shown. Figure 1 The same components are denoted by the same reference numerals, and repeated descriptions are omitted. Figure 1 The depolymerization reaction tank 300 in the figure. The depolymerization product supply unit 300A supplies the depolymerization products such as BHET derived from the first molded product to the polymerization reaction tank 400. The first molded product is decomposed in the depolymerization reaction tank 300 (not shown) which is set in a different place or facility from the illustrated chemical recovery molding system.

[0114] A first preheater 371 may be provided at the rear section of the depolymerization product supply section 300A and the front section of the polymerization reaction tank 400 to heat or preheat the depolymerization product such as BHET supplied from the depolymerization product supply section 300A to a molten state. The first preheater 371 may maintain the depolymerization product at a temperature similar to that of the first preheater 371 provided in the polymerization reaction tank 400. Figure 1 The depolymerization product can be maintained at the same temperature (between 220°C and 250°C) as the heater 320 of the depolymerization reaction tank 300, and the depolymerization product can be maintained at the same temperature (between 250°C and 300°C) suitable for polymerization reaction as the heater 410 attached to the polymerization reaction tank 400.

[0115] In the polymerization reaction tank 400 and / or the by-product removal device 500, EG obtained as a by-product together with PET as a main product can be stored in the EG storage unit 530. The EG stored in the EG storage unit 530 can be used for other purposes at other places or facilities, or can be sold to demanders.

[0116] In the first modification as described above, the polymer resynthesized in the polymerization reaction tank 400 is not made into sheets or pellets, but is directly supplied to the injection molding machine 1 through the polymer supply unit 600. Since the cooling process and heating process associated with the sheets or pellets as in the past are not required, the molded products such as PET bottles can be recovered with less energy than in the past.

[0117] In the chemical recovery device 100 according to the first modification, since the polymer resynthesized in the polymerization reaction tank 400 is directly supplied to the injection molding machine 1, it is necessary to quickly achieve the IV value of the polymer required for the molded product (second molded product). In this modification, in addition to the polymerization reaction tank 400, a byproduct removal device 500 having a function of promoting the polymerization reaction and increasing the IV value of the polymer is provided, so that this requirement can also be fully met.

[0118] Although not shown in the figure, the first modification example may be provided with the same Figure 4 ) The same polymer return section 900. The polymer return section 900 returns at least a portion of the polymer synthesized in the polymerization reaction tank 400 to the polymerization reaction tank 400 instead of sending it to the polymer supply section 600, at least during the period when the injection molding machine 1 cannot receive all the amount of polymer from the polymer supply section 600.

[0119] Fig.15 The second modification of the chemical recovery molding system is shown. Figure 1 and / or Fig.14 The same components are denoted by the same reference numerals, and repeated descriptions are omitted. Figure 1 The polymer supply unit 400A supplies a polymer such as PET derived from a first molded product synthesized in a polymerization reaction tank 400 (not shown) which is located at a different place or facility from the illustrated chemical recovery molding system to the by-product removal device 500 and / or the polymer supply unit 600.

[0120] A second preheater 431 may be provided at the rear section of the polymer supply section 400A and the front section of the by-product removal device 500 and / or the polymer supply section 600 to heat or preheat the polymer such as PET supplied from the polymer supply section 400A to a molten state. The second preheater 431 may maintain the polymer at a temperature similar to that of the preheater provided in the preheater. Figure 1 or Fig.14 The polymer can be maintained at the same temperature (between 250°C and 300°C) as the heater 410 of the polymerization reaction tank 400, or at the same temperature (between 250°C and 290°C) as the heater 520 attached to the by-product removal device 500, or at the same temperature (between 250°C and 290°C) as the heater 620 attached to the polymer supply part 600.

[0121] In the by-product removal device 500, EG obtained together with PET can be stored in the EG storage unit 530. The EG stored in the EG storage unit 530 can be used for other purposes at other places or facilities, or can be sold to demanders.

[0122] In the chemical recovery device 100 according to the second modification, since the polymer supplied from the polymer supply unit 400A is directly supplied to the injection molding machine 1, it is necessary to quickly achieve the IV value of the polymer required for its molded product (second molded product). In this modification, since the byproduct removal device 500 having the function of promoting the polymerization reaction and increasing the IV value of the polymer is provided, this requirement can also be fully met.

[0123] In addition, the configuration, function, and function of each device and method described in the embodiments can be realized by hardware resources or software resources, or by the cooperation of hardware resources and software resources. As hardware resources, for example, processors, ROM, RAM, and various integrated circuits can be used. As software resources, for example, programs such as operating systems and application programs can be used.

[0124] Industrial Applicability

[0125] The present invention relates to a chemical recovery device and the like.

[0126] Explanation of symbols

[0127] 1-injection molding machine, 100-chemical recovery device, 200-polymer adjustment device, 300-depolymerization reaction tank, 300A-depolymerization product supply unit, 301-first depolymerization reaction tank, 302-second depolymerization reaction tank, 320-heater, 371-first preheater, 380-mechanical mixing unit, 381-ultrasonic device, 382-cavitation device, 383-horizontal stirring device, 384-horizontal stirring device, 384A-first horizontal stirring device, 384B-second horizontal stirring device, 400-polymerization reaction tank, 400A-polymer supply unit, 410-heater, 431-second preheater, 500-by-product removal device, 520-heater, 600-polymer supply unit, 610-transfer pump, 620-heater, 710-container, 720-rotating body, 721-rotating plate, 900-polymer return unit.

Claims

1. A chemical recovery device, comprising: A depolymerization reaction tank for decomposing the first molded product composed of a polymer into depolymerized products through a depolymerization reaction; A polymerization reaction tank, synthesizing the depolymerized product into the polymer through a polymerization reaction; and The polymer supply unit supplies the polymer synthesized in the polymerization reaction tank to a molding machine for molding a second molded article.

2. A chemical recovery device comprising: A polymerization reaction tank for synthesizing the polymer by polymerization of a depolymerized product obtained by decomposing the first molded product composed of a polymer through a depolymerization reaction; and The polymer supply unit supplies the polymer synthesized in the polymerization reaction tank to a molding machine for molding a second molded article.

3. A chemical recovery device, comprising: The polymer supply unit supplies the polymer synthesized by a polymerization reaction of a depolymerized product obtained by decomposing the first molded product composed of a polymer through a depolymerization reaction to a molding machine for molding a second molded product.

4. The chemical recovery device according to claim 1 or 2, wherein: A by-product removal device is provided between the polymerization reaction tank and the polymer supply unit. The by-product removal device removes by-products generated together with the polymer by the polymerization reaction in the polymerization reaction tank.

5. The chemical recovery device according to claim 4, wherein: The polymer is polyethylene terephthalate, The depolymerized product is bis(2-hydroxyethyl)terephthalate, The by-product is ethylene glycol.

6. The chemical recovery device according to claim 1 or 2, wherein: The polymer supply unit supplies the polymer synthesized in the polymerization reaction tank to the molding machine in a molten state.

7. The chemical recovery device according to claim 6, wherein: The polymer supply unit includes a first heater that heats the polymer synthesized in the polymerization reaction tank to maintain the polymer in a molten state.

8. The chemical recovery device according to claim 7, wherein: A by-product removal device is provided between the polymerization reaction tank and the polymer supply unit, and the by-product removal device removes by-products generated together with the polymer through the polymerization reaction in the polymerization reaction tank. A second heater for heating the polymer synthesized in the polymerization reaction tank and maintaining it in a molten state is provided in the polymerization reaction tank, the by-product removal device, and / or between them. A first heating temperature by the first heater is higher than a second heating temperature by the second heater.

9. The chemical recovery device according to any one of claims 1 to 3, wherein: The polymer is polyethylene terephthalate, The depolymerized product is bis(2-hydroxyethyl)terephthalate.

10. The chemical recovery device according to any one of claims 1 to 3, wherein: The depolymer includes monomers of the polymer.

11. The chemical recovery device according to any one of claims 1 to 3, wherein: The first molded product and the second molded product are of the same type.

12. The chemical recovery device according to claim 11, wherein: The first molded product and the second molded product are PET bottles.

13. The chemical recovery device according to any one of claims 1 to 3, wherein: The molding machine is an injection molding machine.

14. The chemical recovery device according to claim 2, comprising: The first preheater heats the depolymerized product before supplying it to the polymerization reaction tank.

15. The chemical recovery device according to claim 3, comprising: The second preheater heats the polymer before supplying the polymer to the polymer supply unit.

16. The chemical recovery device according to claim 1 or 2, comprising: The polymer return section returns at least a portion of the polymer synthesized in the polymerization reaction tank to the polymerization reaction tank.

17. The chemical recovery device according to claim 1, comprising: The polymer return section returns at least a portion of the polymer synthesized in the polymerization reaction tank to the depolymerization reaction tank.

18. The chemical recovery device according to claim 1, comprising: The polymer return section returns at least a portion of the polymer synthesized in the polymerization reaction tank to the polymerization reaction tank and the depolymerization reaction tank.

19. The chemical recovery device according to claim 18, wherein: The polymer returning section returns the polymer in excess of the depolymerization reaction tank to the polymerization reaction tank at least before an unreceivable period during which the molding machine cannot receive all the amount of the polymer from the polymer supply section exceeds a predetermined period threshold, and returns the polymer in excess of the polymerization reaction tank to the depolymerization reaction tank after the unreceivable period exceeds the period threshold.

20. The chemical recovery device according to claim 1, wherein: The depolymerization reaction decomposes the polymer into the depolymerized product by a depolymerization material. The depolymerization reaction tank includes a mechanical mixing section that mechanically mixes the depolymerization material and the polymer at least in the early stage of the depolymerization reaction.

21. The chemical recovery device according to claim 20, wherein: The depolymerization reaction tank comprises a first depolymerization reaction tank at the front stage and a second depolymerization reaction tank at the rear stage, The mechanical mixing section is provided at least in the first depolymerization reaction tank.

22. The chemical recovery device according to claim 20 or 21, wherein: The mechanical mixing section mechanically mixes the depolymerized material and the polymer through ultrasonic wave and / or cavitation.

23. The chemical recovery device according to claim 20 or 21, wherein: The mechanical mixing unit comprises: a container to which the depolymerization material and the polymer in a molten state are supplied; and A rotator rotates in the container to mechanically mix the depolymerized material and the polymer.

24. The chemical recovery device according to claim 23, wherein: The rotating body includes a plurality of rotating plates that rotate around an axial rotation axis that intersects the vertical direction, and intervals between the plurality of rotating plates in the axial direction decrease from the front stage toward the rear stage.

25. A chemical recycling molding system, comprising: A depolymerization reaction tank for decomposing the first molded product composed of a polymer into depolymerized products through a depolymerization reaction; A polymerization reaction tank, synthesizing the depolymerized product into the polymer through a polymerization reaction; and The molding machine molds the polymer synthesized in the polymerization reaction tank into a second molded product.

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