De-inking device

Abstract

This invention provides a technology that enables the recovery of plastic from plastic laminates having an ink layer with high yield and purity. [Solution] The deinking apparatus comprises a reaction tank 11, a stirring device 12 that stirs the mixed liquid 90 containing a plastic laminate and a chemical solution supplied to the reaction tank 11 by rotating a stirring blade 123 in the mixed liquid 90, a cleaning device 50A that performs a cleaning process including extracting the mixed liquid 90 from the outlet of the reaction tank 11 and supplying this mixed liquid from a nozzle head 52 to an area of ​​the inner wall surface of the reaction tank 11 located above the liquid surface of the mixed liquid 90, and a controller that controls the operation of the cleaning device 50A so that the cleaning process is performed within the period from when the stirring device 12 starts stirring until it finishes stirring.

Description

Technical Field

[0004] , , ,

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[0001] The present invention relates to a deinking device.

Background Art

[0002] As a countermeasure against environmental pollution caused by plastic products, the importance of plastic recycling is increasing. Patent Document 1 describes a separation and recovery method in which a laminated film including a resin base material layer and other layers such as an ink layer is cut, and the cut pieces are immersed in a release liquid to separate the resin base material layer from the other layers.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a technique that enables the recovery of plastic from a plastic laminate having an ink layer with a high yield and purity.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a deinking apparatus for peeling and deinking a plastic laminate having an ink layer is provided, comprising: a reaction tank having one or more supply ports and discharge ports, through which the plastic laminate and a chemical solution are supplied; a stirring device including a stirring blade, which stirs the mixture containing the plastic laminate and the chemical solution supplied to the reaction tank by rotating the stirring blade; a cleaning device including one or more nozzle heads installed inside the reaction tank, a pipeline with one end connected to the discharge port from outside the reaction tank and the other end connected to the one or more nozzle heads, and a pump installed in the pipeline, which performs a cleaning process that includes extracting the mixture from the discharge port and supplying the mixture from the one or more nozzle heads to a region on the inner wall surface of the reaction tank located above the liquid surface of the mixture contained in the reaction tank; and a controller which controls the operation of the cleaning device so that the cleaning device performs the cleaning process within the period from when the stirring device starts stirring the mixture until it finishes stirring.

[0006] According to another aspect of the present invention, the cleaning apparatus provides a deinking apparatus that removes the mixed liquid from the reaction vessel and supplies it to the area without solid-liquid separation.

[0007] According to yet another aspect of the present invention, a deinking apparatus is provided relating to any of the above aspects, wherein the controller controls the operation of the cleaning apparatus so that the cleaning apparatus performs the cleaning process continuously or intermittently.

[0008] According to another aspect of the present invention, a deinking device is provided in which at least one of the one or more nozzle heads includes a movable part having one or more nozzles for discharging the mixed liquid, and the movable part changes the discharge direction of the one or more nozzles during the cleaning process.

[0009] According to another aspect of the present invention, a deinking apparatus is provided according to any of the above aspects, wherein at least one of the one or more nozzle heads includes an annular hollow body installed so as to circumferentially around the inner surface of the body of the reaction vessel, and the hollow body has a plurality of nozzles arranged circumferentially, each of which discharges the mixture toward the inner surface of the body.

[0010] According to another aspect of the present invention, a deinking apparatus is provided in which the one or more nozzle heads discharge the mixture such that the mixture discharged by them washes the entire area, according to any of the above aspects.

[0011] According to another aspect of the present invention, a deinking apparatus is provided which further comprises an auxiliary cleaning apparatus that includes one or more scrapers and performs an auxiliary cleaning process that includes sliding the one or more scrapers over at least a portion of the area, wherein the controller controls the operation of the auxiliary cleaning apparatus so that the auxiliary cleaning apparatus performs the auxiliary cleaning process within the period of time, according to any of the above aspects.

[0012] According to another aspect of the present invention, the auxiliary cleaning device is provided, which slides one or more scrapers on at least a portion of the area by rotating them around an axis parallel to the height direction.

[0013] Alternatively, according to another aspect of the present invention, the auxiliary cleaning device is provided, which slides one or more scrapers against at least a portion of the area by moving them up and down.

[0014] According to another aspect of the present invention, a deinking apparatus according to any of the above aspects is provided, further comprising one or more supply devices for supplying the plastic laminate and the chemical solution to the reaction vessel.

[0015] According to another aspect of the present invention, a deinking apparatus is provided relating to any of the above aspects, wherein the plastic laminate is a film or sheet with a thickness of 1 mm or less.

[0016] According to another aspect of the present invention, there is provided a deinking device according to any of the above aspects, wherein the plastic laminate is fluff having an average size within a range of 3 mm or more and 8 mm or less.

[0017] According to another aspect of the present invention, there is provided a deinking device according to any of the above aspects, wherein the chemical solution contains water, a basic salt, and a surfactant.

[0018] According to another aspect of the present invention, there is provided a method for producing a deinked product, including: supplying a plastic laminate having an ink layer and a chemical solution to a reaction tank; rotating a stirring blade in a mixed solution containing the plastic laminate and the chemical solution supplied to the reaction tank to stir the mixed solution, thereby causing peeling and deinking of the plastic laminate; withdrawing the mixed solution from the reaction tank within a period from the start to the end of the stirring, and supplying the withdrawn mixed solution to a region located above the liquid surface of the mixed solution accommodated in the reaction tank on the inner wall surface of the reaction tank to wash the inner wall surface.

Advantages of the Invention

[0019] According to the present invention, there is provided a technique that enables the recovery of plastic from a plastic laminate having an ink layer with high yield and purity.

Brief Description of the Drawings

[0020] <​​​​​​​​​​​​​​​​FIG. 6 is a cross-sectional view showing a modified example of the structure of FIG. 5.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific examples of any of the above aspects. The matters described below can be incorporated into each of the above aspects alone or in combination.

[0022] In addition, the embodiments shown below are examples of configurations for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited by the materials, shapes, structures, etc. of the following constituent members. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims described in the claims.

[0023] For elements having the same or similar functions, the same reference numerals are given in the drawings referred to below, and redundant explanations are omitted. Also, the drawings are schematic, and the relationship between dimensions in one direction and dimensions in another direction, and the relationship between the dimensions of one member and the dimensions of other members, etc. may be different from the actual ones.

[0024] <1>First Embodiment FIG. 1 is a block diagram of a deinking device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a part of the structure included in the deinking device of FIG. 1.

[0025] The deinking device 1A shown in FIG. 1 includes a reaction device 10, a first supply device 20, a second supply device 30, a drainage system, a cleaning device 50, and a controller 60. The reaction device 10 includes a reaction tank 11 and a stirring device 12 shown in FIG. 2.

[0026] The reaction tank 11 is a tank that supplies a plastic laminate and a chemical solution and temporarily stores a mixed solution 90 containing them. The reaction tank 11 is supported by a frame or pedestal (not shown).

[0027] The volume of the reaction vessel 11, that is, the sum of the amount of mixed liquid 90 contained in the reaction vessel 11 and the volume of the headspace, is, for example, within the range of 500 L to 4000 L. Furthermore, the amount of mixed liquid 90 contained in the reaction vessel 11 is preferably within the range of 50% to 100% of the volume of the reaction vessel 11, and more preferably within the range of 60% to 90% of the volume of the reaction vessel 11.

[0028] The reaction vessel 11 includes a body, a bottom, and a top plate. The body is a cylindrical part whose height is oriented in the direction of gravity. Here, the body is a cylindrical part whose internal space has a cylindrical shape. The internal space of the body may have other shapes. For example, the internal space of the body may have an elliptical shape, or a rectangular prism shape such as a square prism shape.

[0029] The bottom closes the opening at the bottom of the body. The bottom has an outlet for discharging the mixed liquid 90 from the reaction vessel 11. Here, the bottom is a plate-like portion with a bowl-shaped concave upper surface, and a through-hole serving as the outlet is provided at the lowest point of this upper surface. The upper surface of the bottom may have other shapes. For example, the upper surface of the bottom may be flat. However, from the viewpoint of discharging the mixed liquid 90, it is preferable that the upper surface of the bottom is bowl-shaped concave. The outlet may be provided on the body instead of the bottom.

[0030] At least one of the upper surface of the bottom and the inner surface of the body located below the liquid level of the mixed liquid 90 may have a plurality of protrusions. These protrusions cause turbulence in the flow of the mixed liquid 90 generated by stirring, thereby increasing the shear force applied to the plastic laminate.

[0031] The top plate closes the opening at the top of the body. Here, the top plate is a plate-like part having a lower surface that is recessed in the center relative to the periphery. The lower surface of the top plate may have other shapes. For example, the lower surface of the top plate may be flat. However, from the viewpoint of cleaning the lower surface of the top plate, it is preferable that the lower surface of the top plate is recessed in the center relative to the periphery.

[0032] The top plate has one or more supply ports for supplying the plastic laminate and the chemical solution to the reaction tank 11. The plastic laminate and the chemical solution may be supplied to the reaction tank 11 through the same supply port, or they may be supplied to the reaction tank 11 through separate supply ports. Furthermore, if the chemical solution contains multiple components, the chemical solution containing all of those components may be supplied to the reaction tank 11 through one or more supply ports, or the liquid containing one component and the liquid containing other components may be supplied to the reaction tank 11 through separate supply ports. One or more supply ports may be provided on the body instead of the top plate.

[0033] The reaction apparatus 10 may further include a heater, for example, a jacket heater installed around the reaction vessel 11. The heater heats the mixture 90 contained in the reaction vessel 11 via the reaction vessel 11. By heating the mixture 90, the heater can promote the swelling, decomposition, or dissolution of the adhesive or binder resin contained in the plastic laminate by the chemical solution.

[0034] The stirring device 12 includes a drive unit 121, a support unit (not shown), a shaft 122, and a stirring blade 123. The drive unit 121 is installed above the reaction vessel 11. The drive unit 121 includes a prime mover such as a motor. The drive unit 121 rotatably supports one end of the shaft 122.

[0035] The support portion is a member that supports the drive unit 121. The support portion fixes the relative position of the drive unit 121 with respect to the reaction vessel 11. For example, the support portion fixes the drive unit 121 to the reaction vessel 11, or fixes the drive unit 121 to the frame or base that supports the reaction vessel 11.

[0036] The shaft 122 is suspended by the drive unit 121. A through-hole is provided in the top plate of the reaction vessel 11, and the shaft 122 is inserted into this through-hole. The other end of the shaft 122 is located near the bottom of the reaction vessel 11.

[0037] The stirring blade 123 is attached to the other end of the shaft 122. The stirring blade 123 is positioned in the mixed liquid 90 when the reaction vessel 11 contains the mixed liquid 90. The shape of the stirring blade 123 can be any, such as a propeller blade, a paddle blade, or a turbine blade. When viewed from the axial direction, the diameter of the circle circumscribing the stirring blade 123 of the stirring device 12 is preferably within the range of 30% to 90% of the inner diameter of the reaction vessel 11, and more preferably within the range of 40% to 80%.

[0038] The first supply device 20 is a device for supplying the plastic laminate to the reaction vessel 11. The first supply device 20 includes, for example, a gravimetric feeder or a positive displacement feeder.

[0039] The plastic laminate supplied by the first supply device 20 to the reaction vessel 11 is, for example, in the form of a film or sheet containing a plastic layer. In one example, the plastic laminate is a flexible packaging material. Preferably, the plastic laminate is a film or sheet with a thickness of 1 mm or less.

[0040] The plastic laminate is preferably a fluff cut into small pieces. The fluff preferably has an average size within the range of 3 mm to 8 mm. Here, the average size of the fluff is the arithmetic mean of the lengths of the longest pieces of the fluff.

[0041] The plastic laminate, in one example, comprises a film or sheet made of a thermoplastic resin that does not undergo hydrolysis by an alkaline aqueous solution or is less susceptible to it, one or more layers made of a resin cured product that is readily hydrolyzed by an alkaline aqueous solution, and an ink layer interposed between them. The thermoplastic resin is, for example, polyethylene or polyamide. The resin cured product is, for example, polyethylene terephthalate, or a highly hydrolyzable adhesive cured product or binder resin.

[0042] The second supply device 30 is a device that supplies the chemical solution to the reaction vessel 11. The second supply device 30 includes, for example, a tank containing the chemical solution.

[0043] The chemical solution supplied to the reaction vessel 11 by the second supply device 30 is an alkaline aqueous solution containing water and a basic salt. The basic salt is, for example, sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), ammonia, barium hydroxide (Ba(OH)2), sodium carbonate (Na2CO3), or two or more of these. The concentration of the basic salt in the chemical solution is preferably in the range of 5 g / L to 200 g / L, and more preferably in the range of 10 g / L to 150 g / L.

[0044] This chemical solution may further contain one or more other components, such as a surfactant. Preferably, the chemical solution is a liquid containing water, a basic salt, and a surfactant. The surfactant is preferably one with low foaming properties. The concentration of the surfactant in the chemical solution is preferably in the range of 0.3 g / L to 50 g / L, and more preferably in the range of 0.5 g / L to 30 g / L.

[0045] The drainage system includes a pipeline with one end connected to the outlet of the reaction vessel 11, and a valve installed in this pipeline. Here, the drainage system includes a pipe L1 with one end connected to the outlet of the reaction vessel 11, a valve 40 with a first port connected to the other end of pipe L1, and a pipe L2 with one end connected to the second port of valve 40. Here, valve 40 is an electrically operated or electromagnetic three-way valve. The other end of pipe L2 is connected to a device for post-processing such as washing plastics.

[0046] The cleaning device 50 is, in this case, the cleaning device 50A shown in Figure 2. The cleaning device 50A includes a nozzle head 52, a pipeline with one end connected to the outlet of the reaction vessel 11 from outside the reaction vessel and the other end connected to the nozzle head 52, and a valve 40 and a pump 51 installed in this pipeline. The pipeline includes pipes L1, L3 and L4.

[0047] The cleaning device 50A shares pipe L1 and valve 40 with the drainage system. One end of pipe L3 is connected to the third port of valve 40. Valve 40 can switch the connection state of pipes L1 to L3 between a first state in which pipe L1 is not connected to pipe L2 and pipe L1 is connected to pipe L3, and a second state in which pipe L1 is not connected to pipe L3 and pipe L1 is connected to pipe L2. The other end of pipe L3 is connected to the suction port of pump 51. One end of pipe L4 is connected to the discharge port of pump 51 and the other end is connected to the nozzle head 52. Here, pump 51 is an electric pump.

[0048] The nozzle head 52 is installed inside the reaction vessel 11. Here, the cleaning device 50A includes only one nozzle head 52, but the cleaning device 50A may include two or more nozzle heads 52.

[0049] The cleaning device 50A performs the cleaning process by driving the pump 51. This cleaning process includes extracting the mixed liquid 90 from the outlet of the reaction vessel 11 and supplying the mixed liquid 90 from the nozzle head 52 to an area of ​​the inner wall surface of the reaction vessel 11 that is located above the liquid level of the mixed liquid 90 contained in the reaction vessel 11.

[0050] Preferably, one or more nozzle heads 52 discharge the mixed liquid 90 so that the mixed liquid 90 they discharge washes the entire area. The washing device 50A may be configured to wash the entire area with only one nozzle head 52, or it may be configured to wash the entire area with two or more nozzle heads 52.

[0051] Preferably, at least one of the nozzle heads 52 included in the cleaning device 50A includes a movable part having one or more nozzles for discharging a mixed liquid 90, and this movable part changes the discharge direction of the nozzles during the cleaning process. When such a nozzle head 52 is used, the area that can be cleaned with one nozzle head can be increased. Therefore, when a nozzle head 52 including the above-mentioned movable part is used, the entire area can be washed with fewer nozzle heads 52, for example, with only one nozzle head 52.

[0052] It is preferable that the cleaning device 50A discharges the mixed liquid 90 to the center of the top plate of the reaction tank 11 during the cleaning process. As described above, the lower surface of the top plate is recessed in the center relative to the periphery. Therefore, when the mixed liquid 90 is supplied to the center of the top plate of the reaction tank 11, the mixed liquid flows from the center of the lower surface of the top plate to the periphery of the lower surface of the top plate, and then flows downward along the inner surface of the body. Consequently, in this case as well, it is possible to wash away almost the entire area with a small number of nozzle heads 52, for example, with only one nozzle head 52.

[0053] Preferably, the cleaning device 50A discharges the mixed liquid 90 to an area of ​​the inner surface of the body of the reaction tank 11 that is located above the liquid level of the mixed liquid 90 contained in the reaction tank 11. When the mixed liquid 90 contained in the reaction tank 11 is stirred, a portion of the plastic laminate contained in the mixed liquid 90 adheres to the area of ​​the inner surface of the reaction tank 11 that is located above the liquid level of the mixed liquid 90 contained in the reaction tank 11. A larger amount of plastic laminate can adhere to the area of ​​the inner surface of the body of the reaction tank 11 that is located above the liquid level of the mixed liquid 90 contained in the reaction tank 11 compared to the lower surface of the top plate of the reaction tank 11.

[0054] Preferably, the cleaning device 50A further washes away the portion of the shaft 122 that has been exposed in the reaction tank 11 during the cleaning process. The plastic laminate may also adhere to the aforementioned portion of the shaft 122.

[0055] It is preferable that the washing device 50A removes the mixed liquid 90 from the reaction vessel 11 without separating the solid and liquid components and supplies it to the above-mentioned area. If the mixed liquid 90 is separated into solid and liquid components using a filter such as a mesh filter, the filter will become clogged. If the washing device 50A performs the washing process without separating the solid and liquid components, the filter will not become clogged, and therefore, there is no need to replace or clean a clogged filter.

[0056] The nozzle head 52 may discharge the mixed liquid 90 in any spray shape. For example, the nozzle head 52 may discharge the mixed liquid 90 in a straight line, fan shape, or cone shape. The nozzle head 52 may also discharge the mixed liquid 90 in a shower shape. In any case, it is desirable that the nozzle has a sufficiently large diameter to prevent clogging.

[0057] The controller 60 includes a processing unit 61 and a storage unit 62. The processing unit 61 includes a central processing unit (CPU). The storage unit 62 is connected to the processing unit 61. The storage unit 62 includes non-volatile memory that stores programs read by the processing unit 61 and data supplied by the processing unit 61.

[0058] The controller 60 is connected to the first supply device 20, the second supply device 30, the reaction device 10, the valve 40, and the washing device 50. Specifically, the controller 60 is connected to the first supply device 20, the second supply device 30, the agitator 12, the heater, the valve 40, and the pump 51. The controller 60 controls their operation according to the program described above, for example, as follows.

[0059] When the operator inputs a start command, the controller 60 controls the operation of the valve 40 so that the connection state of pipes L1 to L3 switches from a second state, where pipe L1 is not connected to pipe L3 and pipe L1 is connected to pipe L2, to a first state, where pipe L1 is not connected to pipe L2 and pipe L1 is connected to pipe L3.

[0060] Next, the controller 60 controls the operation of the first supply device 20 and the second supply device 30 so that the first supply device 20 supplies a predetermined amount of plastic laminate to the reaction tank 11, and the second supply device 30 supplies a predetermined amount of chemical solution to the reaction tank 11. The ratio of the amount of plastic laminate to the total amount of plastic laminate supplied by the first supply device 20 to the reaction tank 11 and the amount of chemical solution supplied by the second supply device 30 to the reaction tank 11 is preferably in the range of 1% by mass or more and 20% by mass or less, and more preferably in the range of 5% by mass or more and 10% by mass or less.

[0061] The controller 60 controls the operation of the agitator 12 so that the stirring blades 123 start rotating at the same time that the second supply device 30 starts supplying the chemical solution to the reaction vessel 11, or after a certain period of time has elapsed since the second supply device 30 started supplying the chemical solution to the reaction vessel 11. The controller 60 controls the operation of the agitator 12 so that the stirring blades 123 rotate at a speed preferably in the range of 100 rpm to 1000 rpm, and more preferably in the range of 200 rpm to 500 rpm.

[0062] Furthermore, the controller 60 controls the operation of the heater to start heating the mixed liquid 90 at the same time as the second supply device 30 starts supplying the chemical solution to the reaction vessel 11, or after a certain period of time has elapsed since the second supply device 30 started supplying the chemical solution to the reaction vessel 11, and after the mixed liquid 90 has risen to a sufficiently high temperature, to maintain the temperature of the mixed liquid 90 within a predetermined temperature range. The controller 60 controls the operation of the heater so that the temperature of the mixed liquid 90 contained in the reaction vessel 11 is preferably maintained within a range of 60°C to 90°C, more preferably within a range of 70°C to 85°C.

[0063] Furthermore, the controller 60 controls the operation of the cleaning device 50A, specifically the operation of the pump 51, so that the cleaning device 50A starts the cleaning process at the same time as the stirring blade 123 starts rotating, or after a certain period of time has elapsed since the stirring blade 123 started rotating. For example, the controller 60 controls the operation of the cleaning device 50A so that the cleaning device 50A performs the cleaning process continuously for the period from when the stirring device 12 starts stirring the mixed liquid 90 until it finishes stirring. The controller 60 may also control the operation of the cleaning device 50A so that the cleaning device 50A performs the cleaning process intermittently over the above period.

[0064] The controller 60 controls the operation of the heater to stop heating after any of the above operations have started or after a predetermined time has elapsed since the temperature of the mixed liquid 90 reached a predetermined temperature. Subsequently, the controller 60 controls the operation of the stirring device 12 so that the stirring blade 123 stops rotating, or controls the operation of the stirring device 12 so that the rotational speed of the stirring blade 123 decreases and then the stirring blade 123 stops rotating. The controller 60 also controls the operation of the washing device 50A to stop the washing process after the rotational speed of the stirring blade 123 has decreased or stopped rotating. Furthermore, the controller 60 controls the operation of the valve 40 so that the connection state of pipes L1 to L3 switches from the first state to the second state after the rotational speed of the stirring blade 123 has decreased or stopped rotating. As a result, the mixed liquid 90 containing the deinked product produced by the peeling and deinking of the plastic laminate is sent from the reaction device 10 to the device for post-processing via pipe L2, etc.

[0065] Furthermore, of the controls performed by the controller 60 as described above, all controls except those related to the cleaning device 50A may be performed manually instead of by the controller 60. In other words, the controller 60 only needs to perform the controls related to the cleaning device 50A and does not need to perform one or more other controls.

[0066] According to the deinking apparatus 1A described above, it is possible to recover plastic from a plastic laminate having an ink layer with high yield and purity. This will be explained below.

[0067] To efficiently delaminate and deink plastic laminates, it is desirable to frequently bring the adhesive or binder resin contained in the plastic laminate into contact with the components of the chemical solution, and to apply a strong shear force to the plastic laminate. Furthermore, the thin layer resulting from the delamination of the plastic laminate may contain materials with different specific gravities. Therefore, it is desirable to use, for example, a large-sized stirring blade 123 and to rotate the stirring blade 123 at a high speed. However, when stirring is performed under such conditions, solid materials such as the plastic laminate contained in the mixture 90 will adhere to the area of ​​the inner surface of the reaction vessel 11 that is located above the mixture 90 contained in the reaction vessel 11.

[0068] In plastic laminates attached to this region, swelling or dissolution of the adhesive or binder resin they contain by chemical solutions hardly progresses. Furthermore, no shear force due to stirring is applied to plastic laminates attached to this region. In addition, adsorption of surfactants to colorants such as pigments they contain is unlikely to occur in plastic laminates attached to this region. Therefore, peeling and deinking hardly progress in plastic laminates attached to the above region.

[0069] If the above-described cleaning process is not performed, the plastic laminate will continue to adhere to the above-mentioned area, resulting in a significant amount of plastic laminate accumulating in that area. If these plastic laminates do not fall back into the mixed liquid 90 within the period until the drainage of the mixed liquid 90 from the reaction apparatus 10 is completed, the plastic cannot be recovered with a high yield.

[0070] Furthermore, if the above-mentioned cleaning process is not performed, the plastic laminates accumulated in the above-mentioned area may detach from the area by their own weight and fall into the mixed liquid 90 within the period until the drainage of the mixed liquid 90 from the reaction device 10 is completed. In this case, it may be possible to recover the plastic with a high yield. However, the plastic laminates do not necessarily detach from the above-mentioned area by their own weight. Also, even if the plastic laminates detach from the above-mentioned area by their own weight, the time required from adhesion to detachment is not short. In plastic laminates that have accumulated in the above-mentioned area for a long time, detachment and deinking have hardly progressed, and therefore, when these fall into the mixed liquid 90, the mixed liquid 90 discharged from the reaction device 10 will be contaminated with plastic laminates that have not undergone sufficient detachment and deinking.

[0071] For these reasons, if the aforementioned cleaning process is not performed, it is not possible to recover plastic from the plastic laminate containing the ink layer with high yield and purity.

[0072] The deinking apparatus 1A described above can achieve a high yield because it performs the cleaning process described above. Furthermore, this cleaning process can significantly reduce the time required for individual plastic laminates to return to the mixed liquid 90 after adhering to the above area. Therefore, there is almost no decrease in purity due to the plastic laminates adhering to the above area returning to the mixed liquid 90. Accordingly, the deinking apparatus 1A described above can recover plastic from plastic laminates having an ink layer with high yield and purity.

[0073] The cleaning solution supplied from the nozzle head 52 to the above-mentioned region is a mixed solution 90 containing plastic laminate. This supply allows the plastic laminate adhering to the region to be returned to the mixed solution 90 being stirred by the agitator 12. However, some of the plastic laminate contained in the cleaning solution may adhere to the region. Nevertheless, any plastic laminate adhering to the region through this route can be quickly washed away by the cleaning process described above. Therefore, the plastic laminate adhering to the region through the above-mentioned route does not significantly affect the yield and purity.

[0074] Furthermore, in the deinking apparatus 1A described above, after the deinking process is completed, that is, after the mixed liquid 90 is transferred from the reaction apparatus 10 to the apparatus for post-processing, a small amount of solid material may remain attached to the inner surface of the reaction tank 11. This solid material can be recovered during the next deinking process performed in the deinking apparatus 1A. The solid material remaining attached to the inner surface of the reaction tank 11 may be washed away with a washing solution such as water after the mixed liquid 90 has been drained.

[0075] As described above, the cleaning liquid supplied from the nozzle head 52 to the above-mentioned area is a mixed liquid 90 containing a plastic laminate. Therefore, as described above, the cleaning device 50A can draw the mixed liquid 90 from the reaction vessel 11 and supply it to the above-mentioned area without separating the solid and liquid. In this case, filter clogging does not occur, and therefore, replacement or cleaning of a clogged filter is unnecessary. Consequently, in this case, high maintainability can be achieved.

[0076] The deinking device 1A described above can be modified in various ways. For example, instead of the structure described with reference to Figure 2, the deinking device 1A can adopt the structure shown in Figure 3.

[0077] Figure 3 is a cross-sectional view showing a modified example of the structure in Figure 2. The structure shown in Figure 3 is the same as the structure described with reference to Figure 2, except that it includes a cleaning device 50B instead of a cleaning device 50A. Furthermore, the cleaning device 50B is the same as the cleaning device 50A described with reference to Figure 2, except that it includes a nozzle head 52B instead of a nozzle head 52.

[0078] The nozzle head 52B includes an annular hollow body that is positioned to encircle the inner surface of the shell of the reaction vessel 11. Here, the annular hollow body is positioned near the top plate of the reaction vessel 11.

[0079] This hollow body has multiple nozzles arranged circumferentially, each discharging a mixture 90 toward the inner surface of the body. These nozzles are positioned so that the mixture 90 they discharge washes away substantially the entire area of ​​the inner surface of the body of the reaction tank 11 that is located above the liquid level of the mixture 90.

[0080] Although the washing device 50B cannot wash the underside of the top plate of the reaction tank 11, it can wash almost the entire area of ​​the inner surface of the body of the reaction tank 11 that is located above the liquid level of the mixed liquid 90. Therefore, with the deinking device 1A employing the structure shown in Figure 3, plastic can be recovered from the plastic laminate having an ink layer with almost the same yield and purity as the deinking device 1B employing the structure shown in Figure 2. Furthermore, the deinking device 1A employing the structure shown in Figure 3 has almost the same effect as the deinking device 1B employing the structure shown in Figure 2 in other respects as well.

[0081] The structure shown in Figure 3 may be modified by adding the nozzle head 52, as explained with reference to Figure 2. This allows for the washing of the area of ​​the body of the reaction vessel 11 that is located above the liquid level of the mixed liquid 90, as well as the washing of the underside of the top plate of the reaction vessel 11.

[0082] <2> Second Embodiment Figure 4 is a block diagram of a deinking apparatus according to a second embodiment of the present invention. Figure 5 is a cross-sectional view showing a part of the structure included in the deinking apparatus of Figure 4.

[0083] The deinking apparatus 1B shown in Figure 4 is the same as the deinking apparatus 1A described with reference to Figures 1 and 2, except for the following points.

[0084] In other words, the deinking device 1B further includes an auxiliary cleaning device 70. The auxiliary cleaning device 70 is, in this case, the auxiliary cleaning device 70A shown in Figure 5. The auxiliary cleaning device 70A includes a drive unit 71A, a shaft 72A, a support member 73A, and a scraper 74A.

[0085] The drive unit 71A is installed between the reaction vessel 11 and the drive unit 121. The shaft 122 of the agitator 12 passes through the drive unit 71A.

[0086] The drive unit 71A includes a prime mover such as a motor. The drive unit 71A rotatably supports one end of the shaft 72A. The drive unit 71A may also be capable of further moving the shaft 72A up and down, or further vibrating the shaft 72A.

[0087] The shaft 72A is suspended by the drive unit 71A. The shaft 72A is inserted into a through hole provided in the top plate of the reaction vessel 11. The other end of the shaft 122 is located below the lower end of the nozzle head 52.

[0088] Shaft 72A is a pipe, such as a cylindrical tube. The shaft 122 of the agitator 12 is inserted into shaft 72A.

[0089] The support member 73A is attached to the lower end of the shaft 72A. Here, the support member 73A includes a plurality of arm portions that extend radially from the lower end of the shaft 72A toward the body of the reaction vessel 11. These arm portions are located below the lower end of the nozzle head 52 so as not to interfere with the nozzle head 52. The support member 73A may also include a plate-like portion having a substantially disc shape, with a through hole in the center into which the shaft 72A is inserted, and one or more further through holes located off-center.

[0090] The scraper 74A is supported by the support member 73A. Here, the scraper 74A is supported by the arm portion included in the support member 73A.

[0091] Each of the scrapers 74A has a plate shape. Here, each of the scrapers 74A has a roughly rectangular shape. Specifically, each of the scrapers 74A is supported by an arm on one long side, and the other long side is in contact with a region of the inner surface of the body of the reaction vessel 11 that is located above the liquid surface of the mixed liquid 90. In addition, one short side of each of the scrapers 74A is located slightly above the liquid surface of the mixed liquid 90, and the other short side is located near the top plate of the reaction vessel 11.

[0092] As will be described later, the scraper 74A scrapes off solid matter adhering to the inner wall surface of the reaction vessel 11 by sliding circumferentially against at least a portion of the area located above the liquid surface of the mixed liquid 90 contained in the reaction vessel 11. The scraper 74A may be supported by a support member 73A so as to tilt forward with respect to its sliding direction. With this configuration, at least a portion of the solid matter scraped off by the scraper 74A can move along the scraper 74A toward its lower end as the scraper 74A slides.

[0093] Each of the scrapers 74A may have a different shape. For example, each of the scrapers 74A may have a rod shape extending in the height direction of the reaction vessel 11. In this case, the cross-section of each of the scrapers 74A perpendicular to the height direction may have any shape. For example, the above cross-section may be a polygon such as a triangle or a quadrilateral, or it may be a circle, an ellipse or an oblong.

[0094] Furthermore, although each of the scrapers 74A is positioned to contact a region of the inner surface of the body of the reaction vessel 11 that is above the liquid surface of the mixed liquid 90, they may also be positioned to contact the peripheral region of the lower surface of the top plate of the reaction vessel 11, or to contact both of these regions. When the scrapers 74A are positioned to contact the peripheral region of the lower surface of the top plate of the reaction vessel 11, care should be taken to ensure that they do not interfere with the pipe L4 and the nozzle head 52.

[0095] Each of the scrapers 74A is made of, for example, a cured resin, rubber, metal, ceramic, or wood. Each of the scrapers 74A may be made of two or more materials.

[0096] In this example, the auxiliary cleaning device 70A includes multiple scrapers 74A, but the auxiliary cleaning device 70A may include only one scraper 74A.

[0097] The auxiliary cleaning device 70A performs an auxiliary cleaning process that includes sliding a scraper 74A against at least a portion of the inner wall surface of the reaction vessel 11 that is located above the liquid surface of the mixed liquid 90 contained in the reaction vessel 11. Here, as the drive device 71A rotates the shaft 72A, each of the scrapers 74A, supported by the shaft 72A via the support member 73A, rotates around an axis parallel to the height direction while sliding against the region of the inner wall surface of the reaction vessel 11 that is located above the liquid surface of the mixed liquid 90 contained in the reaction vessel 11. By sliding against the above region, the scraper 74A scrapes off solid matter such as plastic laminates that could not be washed away by the cleaning process.

[0098] In the deinking device 1B, the controller 60 is further connected to the auxiliary cleaning device 70, in this case to the auxiliary cleaning device 70A. In addition to performing the above-described control for the deinking device 1A, the controller 60 also performs the control described below.

[0099] The controller 60 controls the operation of the auxiliary cleaning device 70A, specifically the operation of the drive device 71A, so that the auxiliary cleaning device 70A starts the auxiliary cleaning process at the same time as the stirring blade 123 starts rotating, or after a certain period of time has elapsed since the stirring blade 123 started rotating. For example, the controller 60 controls the operation of the auxiliary cleaning device 70A so that the auxiliary cleaning device 70A performs the auxiliary cleaning process continuously for the period from when the stirring device 12 starts stirring the mixed liquid 90 until it finishes stirring. The controller 60 may also control the operation of the auxiliary cleaning device 70A so that the auxiliary cleaning device 70A performs the auxiliary cleaning process intermittently for the above period.

[0100] When the controller 60 controls the operation of the auxiliary cleaning device 70A so that it performs the auxiliary cleaning process intermittently, that is, when it controls the operation of the auxiliary cleaning device 70A so that a sliding period in which the scraper 74A is slid in the circumferential direction and a rest period in which the scraper 74A is not slid in the circumferential direction are repeated alternately, the controller 60 may control the operation of the auxiliary cleaning device 70A so that in each sliding period the sliding of each scraper 74A is one full rotation or more. Alternatively, the controller 60 may control the operation of the auxiliary cleaning device 70A so that in each sliding period the sliding of each scraper 74A is less than one full rotation. In either case, it is desirable that the total area over which the scraper 74A slides in each sliding period covers the entire circumference.

[0101] If the drive unit 71A is capable of moving the shaft 72A up and down, the controller 60 may control the operation of the auxiliary cleaning device 70A during the pause period so that it performs a sinking operation that submerges the scraper 74A at least partially into the mixed liquid 90. Alternatively, if the drive unit 71A is capable of vibrating the shaft 72A, the controller 60 may control the operation of the auxiliary cleaning device 70A so that it performs a vibrating operation that vibrates the scraper 74A during the sliding period or pause period. Performing these operations allows solid matter attached to the scraper 74A to be transferred from the scraper 74A into the mixed liquid 90.

[0102] This deinking device 1B has the same effect as the deinking device 1A, which was described with reference to Figures 1 and 2. Furthermore, because the deinking device 1B performs the auxiliary cleaning process described above, it can more reliably remove solid matter adhering to the area of ​​the inner wall surface of the reaction tank 11 that is located above the liquid level of the mixed liquid 90 contained in the reaction tank 11.

[0103] The deinking device 1B described above can be modified in various ways. For example, instead of the structure described with reference to Figure 5, the deinking device 1B can adopt the structure shown in Figure 6.

[0104] Figure 6 is a cross-sectional view showing a modified example of the structure in Figure 5. The structure shown in Figure 6 is the same as the structure described with reference to Figure 5, except that it includes an auxiliary cleaning device 70B instead of an auxiliary cleaning device 70A.

[0105] The auxiliary cleaning device 70B includes a drive unit 71B, a shaft 72B, a support member 73B, and a scraper 74B.

[0106] The drive unit 71B includes a prime mover such as a motor. The drive unit 71B supports one end of the shaft 72B so that it can move up and down. In other words, the drive unit 71B is a lifting device. The drive unit 71B may also be capable of further rotating the shaft 72B, or further vibrating the shaft 72B.

[0107] The shaft 72B is suspended by the drive unit 71B. The shaft 72B is inserted into a through hole provided in the top plate of the reaction vessel 11. The shaft 72B is a tube such as a cylindrical pipe. The shaft 122 of the stirring device 12 is inserted into the shaft 72B.

[0108] The support member 73B is attached to the lower end of the shaft 72B. Here, the support member 73B includes a plurality of arm portions that extend radially from the lower end of the shaft 72B toward the body of the reaction vessel 11. These arm portions are provided so as not to interfere with the nozzle head 52. The support member 73B may also include a plate-like portion having a substantially disc shape, with a through hole in the center into which the shaft 72A is inserted, and at least one more through hole provided at the position of the nozzle head 52.

[0109] The scraper 74B here has a cylindrical shape that widens from one end to the other. The scraper 74B is supported by a support member 73B such that the end with the larger diameter is located below the end with the smaller diameter. Here, the scraper 74B is supported by an arm portion included in the support member 73B. The lower edge of the scraper 74B is in contact with the inner surface of the shell of the reaction vessel 11 along its entire circumference.

[0110] The scraper 74B may have other shapes. For example, the scraper 74B may have a cylindrical shape with a constant diameter from one end to the other.

[0111] The scraper 74B may be made of, for example, a cured resin, rubber, metal, ceramic, or wood. The scraper 74B may also be made of two or more materials.

[0112] If the drive unit 71B is capable of rotating the shaft 72B, the scraper 74B does not have to have a cylindrical shape. For example, the scraper 74B may have a plate shape in which the lower end is curved along the inner surface of the shell of the reaction tank 11, and the circumferential dimension of this end is shorter than the inner circumference of the shell. The auxiliary cleaning device 70B may include only one or more scrapers 74B of such shape.

[0113] Even if the drive unit 71B cannot rotate the shaft 72B, the auxiliary cleaning device 70B may include multiple scrapers. For example, if multiple scrapers, each having the plate shape described above, are supported by a support member 73B so that they are arranged without gaps in the circumferential direction, the group of scrapers consisting of these scrapers can perform the same function as a cylindrical scraper 74B.

[0114] The auxiliary cleaning device 70B performs an auxiliary cleaning process that includes sliding the scraper 74B against at least a portion of the inner wall surface of the reaction vessel 11 that is located above the liquid level of the mixed liquid 90 contained in the reaction vessel 11. Specifically, first, the drive device 71B lowers the shaft 72B, and the scraper 74B, which is supported by the shaft 72B via the support member 73B, slides downward against the area of ​​the inner wall surface of the reaction vessel 11 that is located above the liquid level of the mixed liquid 90 contained in the reaction vessel 11. By sliding against the above area, the scraper 74B scrapes off solid matter such as plastic laminates that could not be washed away by the cleaning process. After that, the drive device 71B raises the shaft 72B, thereby returning the scraper 74B to its original position.

[0115] When the structure shown in Figure 6 is adopted, the controller 60 performs the same control as the controller 60 of the deinking device 1B described with reference to Figures 4 and 5, except for the following points. That is, instead of controlling the operation of the auxiliary cleaning device 70A, the controller 60 controls the operation of the auxiliary cleaning device 70B as follows.

[0116] Specifically, the controller 60 controls the operation of the auxiliary cleaning device 70B, specifically the operation of the drive device 71B, so that the auxiliary cleaning device 70A starts the auxiliary cleaning process at the same time as the stirring blade 123 starts rotating, or after a certain period of time has elapsed since the stirring blade 123 started rotating. For example, the controller 60 controls the operation of the auxiliary cleaning device 70B so that the auxiliary cleaning device 70B performs the auxiliary cleaning process continuously for the period from when the stirring device 12 starts stirring the mixed liquid 90 until it finishes stirring. The controller 60 may also control the operation of the auxiliary cleaning device 70B so that the auxiliary cleaning device 70B performs the auxiliary cleaning process intermittently over the above period.

[0117] The controller 60 may control the operation of the auxiliary cleaning device 70B so that the descent of the shaft 72B by the drive unit 71B stops before the lower end of the scraper 74B reaches the liquid surface of the mixed liquid 90. Alternatively, the controller 60 may control the operation of the auxiliary cleaning device 70B so that the descent of the shaft 72B by the drive unit 71B stops after at least the lower end of the scraper 74B has reached below the liquid surface of the mixed liquid 90. In the latter case, solid matter adhering to the scraper 74B can be transferred from the scraper 74B into the mixed liquid 90.

[0118] If the drive unit 71B is capable of vibrating the shaft 72B, the controller 60 may control the operation of the auxiliary cleaning device 70B to vibrate the scraper 74B during one or more of the following periods: the downward period when the drive unit 71B is lowering the shaft 72B, the upward period when the drive unit 71B is raising the shaft 72B, and other periods. Even when this operation is performed, solid matter attached to the scraper 74B can be transferred from the scraper 74B into the mixed liquid 90.

[0119] If the drive unit 71B is capable of rotating the shaft 72B, then, as described above, the auxiliary cleaning device 70B may include, for example, one or more scrapers, each having a plate shape in which the lower end is curved along the inner surface of the shell of the reaction vessel 11, and the circumferential dimension of this end is shorter than the inner circumference of the shell. If the controller 60 controls the operation of the auxiliary cleaning device 70B so that the vertical movement and rotation of the shaft 72B by the drive unit 71B are performed appropriately, then even when using such scrapers, solid matter can be scraped off from almost all of the area of ​​the inner wall surface of the reaction vessel 11 that is located above the liquid surface of the mixed liquid 90 contained in the reaction vessel 11.

[0120] The deinking apparatus 1B employing this structure also achieves the same effects as the deinking apparatus 1A described with reference to Figures 1 and 2. Furthermore, because the deinking apparatus 1B employing this structure performs the auxiliary cleaning process described above, it can more reliably remove solid matter adhering to the area of ​​the inner wall surface of the reaction tank 11 that is located above the liquid surface of the mixed liquid 90 contained in the reaction tank 11, compared to the deinking apparatus 1A described with reference to Figures 1 and 2.

[0121] Although the structures shown in Figures 5 and 6 include a cleaning device 50A, a cleaning device 50B may be included instead of cleaning device 50A. Furthermore, a nozzle head 52B, as described with reference to Figure 3, may be added to the structures shown in Figures 5 and 6. [Explanation of Symbols]

[0122] 1A...Deinking device, 1B...Deinking device, 10...Reaction device, 11...Reaction tank, 12...Agitator, 20...First supply device, 30...Second supply device, 40...Valve, 50...Washing device, 50A...Washing device, 50B...Washing device, 51...Pump, 52...Nozzle head, 52B...Nozzle head, 60...Controller, 61...Processing unit, 62...Storage unit, 70...Auxiliary washing device, 70A...Auxiliary washing device, 70B...Auxiliary washing device, 71A...Drive device, 71B...Drive device, 72A...Shaft, 72B...Shaft, 73A...Support member, 73B...Support member, 74A...Scraper, 74B...Scraper, 90...Mixed liquid, 121...Drive device, 122...Shaft, 123...Agitator blade, L1...Tube, L2...Tube, L3...Tube, L4...Tube.

Claims

1. A deinking apparatus for peeling and deinking a plastic laminate having an ink layer, A reaction tank having one or more supply ports and discharge ports, through which the plastic laminate and the chemical solution are supplied, A stirring device comprising a stirring blade, which stirs the mixture containing the plastic laminate and the chemical solution supplied to the reaction vessel by rotating the stirring blade, A cleaning apparatus comprising one or more nozzle heads installed inside the reaction vessel, a pipeline with one end connected to the discharge port from outside the reaction vessel and the other end connected to the one or more nozzle heads, and a pump installed in the pipeline, wherein the cleaning apparatus includes extracting the mixed liquid from the discharge port and supplying the mixed liquid from the one or more nozzle heads to a region of the inner wall surface of the reaction vessel located above the liquid level of the mixed liquid contained in the reaction vessel, A controller that controls the operation of the cleaning device so that the cleaning device performs the cleaning process within the period from when the stirring device starts stirring the mixture until it stops. A deinking device equipped with [a specific feature].

2. The deinking apparatus according to claim 1, wherein the washing apparatus removes the mixed liquid from the reaction tank without solid-liquid separation and supplies it to the area.

3. The deinking apparatus according to claim 1, wherein the controller controls the operation of the cleaning apparatus so that the cleaning apparatus performs the cleaning continuously or intermittently.

4. The deinking apparatus according to claim 1, wherein at least one of the one or more nozzle heads includes a movable part having one or more nozzles for discharging the mixed liquid, and the movable part changes the discharge direction of the one or more nozzles during the cleaning process.

5. The deinking apparatus according to claim 1, wherein at least one of the one or more nozzle heads includes an annular hollow body installed so as to circumferentially around the inner surface of the body of the reaction vessel, and the hollow body has a plurality of nozzles arranged in the circumferential direction, each of which discharges the mixed liquid toward the inner surface of the body.

6. The deinking apparatus according to claim 1, wherein the one or more nozzle heads discharge the mixed liquid such that the mixed liquid they discharge washes the entire area.

7. The device further includes an auxiliary cleaning device which includes one or more scrapers and performs an auxiliary cleaning process which includes sliding the one or more scrapers over at least a portion of the area, The deinking apparatus according to claim 1, wherein the controller controls the operation of the auxiliary cleaning device so that the auxiliary cleaning device performs the auxiliary cleaning process within the period.

8. The deinking device according to claim 7, wherein the auxiliary cleaning device slides one or more scrapers on at least a portion of the area by rotating them around an axis parallel to the height direction.

9. The deinking device according to claim 7, wherein the auxiliary cleaning device slides over at least a portion of the area by moving one or more scrapers up and down.

10. The deinking apparatus according to claim 1, further comprising one or more supply devices for supplying the plastic laminate and the chemical solution to the reaction tank.

11. The deinking apparatus according to claim 1, wherein the plastic laminate is a film or sheet with a thickness of 1 mm or less.

12. The deinking apparatus according to claim 1, wherein the plastic laminate is a fluff having an average size within the range of 3 mm to 8 mm.

13. The deinking apparatus according to claim 1, wherein the chemical solution comprises water, a basic salt, and a surfactant.

14. The process involves supplying a plastic laminate having an ink layer and a chemical solution to a reaction vessel. The mixture containing the plastic laminate and the chemical solution supplied to the reaction vessel is stirred by rotating a stirring blade to cause the plastic laminate to peel and deink, During the period from the start to the end of the stirring, the mixed liquid is removed from the reaction vessel, and this removed mixed liquid is supplied to the area of ​​the inner wall surface of the reaction vessel that is located above the liquid level of the mixed liquid contained in the reaction vessel, thereby cleaning the inner wall surface. A method for manufacturing a deinked product containing ink.

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