Decolorization method

Abstract

To suitably decolorize a decolorization target without depending on a shape or a size of the decolorization target.SOLUTION: In a decolorization method for removing pigments of a dye from a decolorization target including fibers dyed or colored with the dye, the pigments are retained gaps in molecular chains of the fibers, respectively. The method includes a step of washing the decolorization target with a first decolorizing solution at a decolorization temperature equal to or higher than a fiber-opening temperature that loosens the molecular chains to an extent that the pigments move out from the gaps of the molecular chains of the fibers included in the decolorization target.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a decolorization method.

Background Art

[0002] Currently, a technique for printing on fabric using transfer printing is known. Transfer printing is a printing method in which an image is drawn on a transfer sheet with transfer ink, and the image drawn on the transfer sheet is transferred to the fabric. Also, for recycling of fabric, a technique for decolorizing the fabric to remove the image from the fabric on which the image is drawn is known.

[0003] For example, Patent Document 1 describes a technique for discharging a discharging agent onto a dyed fabric by an inkjet method for discharging. Patent Document 1 describes an inkjet printing apparatus for discharging discharging ink for such discharging.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the inkjet printing apparatus described in Patent Document 1, in addition to applying a solvent to the object to be decolorized, heat pressing to the absorber that absorbs the object to be decolorized and the solvent, and supplying the absorber to the object to be decolorized are required. For this reason, with this method, it has been difficult to decolorize an object to be decolorized having a three-dimensional shape such as a stuffed toy. Also, since a large absorber is required in proportion to the area of the region to be decolorized, when the object to be decolorized becomes large, a large amount of the absorber becomes waste, which is uneconomical and has a high environmental load.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a decolorization method capable of suitably decolorizing an object to be decolorized regardless of the shape and size of the object to be decolorized.

Means for Solving the Problems

[0007] A decolorization method for decolorizing a pigment of a dye from an object to be decolorized including a fiber dyed or colored with the dye according to a first aspect of the present invention is the pigment is held in a gap between molecular chains of the fiber, a decolorization step of washing the object to be decolorized with a first decolorization liquid having a decolorization temperature equal to or higher than an opening temperature at which the molecular chains are loosened to such an extent that the pigment escapes from the gaps between the molecular chains of the fiber contained in the object to be decolorized, including.

[0008] the dye is a disperse dye, the fiber may be a fiber that can be dyed or colored with the disperse dye.

[0009] In the decolorization step, in a treatment tank, the fiber and the first decolorization liquid having the decolorization temperature may be brought into contact with each other.

[0010] In the decolorization step, the object to be decolorized may be carried into the first decolorization liquid in the treatment tank containing the first decolorization liquid heated to the decolorization temperature.

[0011] In the decolorization step, in the treatment tank containing the object to be decolorized and the first decolorization liquid having a temperature lower than the decolorization temperature, the first decolorization liquid may be heated to the decolorization temperature.

[0012] The decolorization step may include a stimulation application step of applying mechanical stimulation to the object to be decolorized after or during contact of the first decolorization liquid with the fiber.

[0013] The stimulation application step may include any one of a step of stirring, a step of shaking, and a step of ultrasonic treatment of the first decolorization liquid in which the object to be decolorized is placed in the treatment tank.

[0014] The decolorization step may be performed by supplying the new or recycled first decolorizing liquid to the treatment tank and discharging the excess first decolorizing liquid from the treatment tank.

[0015] The decolorization step may include a step of spraying the first decolorizing liquid onto the object to be decolorized as a liquid or a gas at the decolorization temperature.

[0016] After the decolorization step, a rinsing step of bringing the second decolorizing liquid for decolorizing the pigment into contact with the object to be decolorized may further be included.

[0017] The second decolorizing liquid may be the same type of liquid as the first decolorizing liquid.

[0018] A liquid discharging step of discharging the first decolorizing liquid from the object to be decolorized and a drying step of drying the object to be decolorized may further be included.

[0019] The fiber may include at least one of polyester fiber and nylon fiber.

[0020] The decolorization temperature may be lower than the boiling point of the first decolorizing liquid.

Advantages of the Invention

[0021] According to the present disclosure, the object to be decolorized can be suitably decolorized without depending on the shape and size of the object to be decolorized.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0023] (First Embodiment) A decolorization method according to the first embodiment of the present invention for decolorizing a disperse dye dyed or colored on a decolorization target object with a decolorization liquid from the decolorization target object will be described. In this decolorization method, as shown in FIG. 1, a decolorization step S1, a rinsing step S2, a liquid removal step S3, and a drying step S4 are mainly performed.

[0024] (Decolorization Target Object) The decolorization target object is an arbitrary article containing polyester fibers or nylon fibers, on which disperse dyes are dyed or colored. For example, the decolorization target object may include a knit or fabric formed from polyester yarn, nylon yarn, polyester blended yarn, or nylon blended yarn. Examples of fibers blended with polyester or nylon include cotton, polyurethane, rayon, and hemp, and blends of polyester and nylon are also included. The blending ratio of polyester or nylon to other blended yarns (polyester or nylon: other blended yarns) may be 50:50 or more, 60:40 or more, 65:35 or more, 70:30 or more, 75:25 or more, 80:20 or more, 85:15 or more, 90:10 or more. The shape of the decolorization target object is arbitrary, and examples of the decolorization target object include flags, clothes, and fabrics.

[0025] (Disperse Dye) Disperse dyes are arbitrary as long as the dyes contained therein are incorporated into the gaps between the molecular chains of polyester fibers or nylon fibers in the object to be decolorized, thereby dyeing or coloring these fibers. Examples of methods for dyeing polyester fibers or nylon fibers in the object to be decolorized with disperse dyes include sublimation transfer printing, direct sublimation printing, exhaustion dyeing, or thermosol dyeing.

[0026] (Decolorizing liquid) The decolorizing liquid used in the decolorizing step S1 and the rinsing step S2 described later is arbitrary as long as it (i) has a boiling point exceeding the temperature at which these steps are performed, particularly the decolorizing temperature in the decolorizing step S1, (ii) can dissolve the disperse dye in the decolorizing liquid, and (iii) does not cause significant adverse effects on the object to be decolorized. Examples of adverse effects to be avoided on the object to be decolorized include, for example, changes in the color of the fibers themselves constituting the object to be decolorized, deterioration of the texture of the fibers, and shrinkage of the fibers.

[0027] Examples of the main component of the decolorizing liquid include organic solvents. For example, such organic solvents include dimethyl succinate (boiling point: 200 °C), dimethyl glutarate (boiling point: 214 °C), dimethyl adipate (boiling point: 245 °C), ethyl acetate di-ukizole (boiling point: 218 °C), 3-methoxy-N,N-dimethylpropanamide (boiling point: 215 °C), benzyl benzoate (boiling point: 325 °C), diethylene glycol (boiling point: 245 °C), trichloroethane (boiling point: 74 °C), dimethyl sulfoxide (boiling point: 189 °C), acetone (boiling point: 56 °C), methyl ethyl ketone (boiling point: 80 °C), propylene glycol monomethyl ether acetate (boiling point: 146 °C), etc. These components may be appropriately diluted with a solvent such as water or other organic solvents.

[0028] (Decolorizing step S1) In the decolorizing step S1, the object to be decolorized is washed with the decolorizing liquid in a first treatment tank filled with the decolorizing liquid at a predetermined decolorizing temperature.

[0029] Polyester fibers or nylon fibers dyed with a disperse dye contained in the object to be decolorized hold the pigment of the disperse dye in the gaps between the molecular chains of those fibers. At normal temperature, the pigment of the disperse dye present in the gaps between the molecular chains has high washing fastness, and such disperse dyes are not easily decolorized. However, when the polyester fibers or nylon fibers are heated at a high temperature, the gaps between their molecular chains widen, whereby the pigment of the disperse dye easily escapes from the fibers, and thus, it becomes easily decolorized.

[0030] Therefore, in the decolorization step S1, as the decolorization temperature, a decolorization temperature equal to or higher than the fibrillation temperature at which the molecular chains are loosened until the gaps between the molecular chains of the polyester fibers or nylon fibers contained in the object to be decolorized widen to such an extent that the pigment of the disperse dye escapes from the gaps is used. For example, the decolorization temperature may be equal to or higher than the glass transition point of the polyester fibers or nylon fibers contained in the object to be decolorized. Further, the decolorization temperature may be a temperature corresponding to the dyeing temperature in the exhaustion dyeing method, for example, a temperature equal to or higher than the dyeing temperature. In particular, when the object to be decolorized contains polyester fibers, the decolorization temperature may be 110°C or higher, 115°C or higher, 120°C or higher, 125°C or higher, 130°C or higher. Also, when the object to be decolorized contains nylon fibers, the decolorization temperature may be 70°C or higher, 80°C or higher, 90°C or higher, 100°C or higher. Further, the decolorization temperature is lower than the boiling point of the decolorizing liquid.

[0031] In the decolorization step S1, in order to wash and decolorize the object to be decolorized with the decolorizing liquid, a heating step of heating the object to be decolorized through the decolorizing liquid and a stirring step of stirring the object to be decolorized and the decolorizing liquid are mainly performed.

[0032] In the heating step, the object to be decolorized is heated through the decolorizing liquid in a first treatment tank filled with the decolorizing liquid at the decolorization temperature. For example, in the first treatment tank, the object to be decolorized and the decolorizing liquid at the decolorization temperature are separately brought into contact with each other, and in particular, the fibers contained in the object to be decolorized and the decolorizing liquid at the decolorization temperature are brought into contact with each other. Thereby, the temperature of the object to be decolorized approaches the decolorization temperature, the molecular chains of the polyester fibers or nylon fibers contained in the object to be decolorized are loosened, and it is expected that the pigment of the disperse dye is easily decolorized from the gaps between the molecular chains of these fibers.

[0033] The heating step may be performed by simultaneously or sequentially introducing the object to be decolorized and the decolorizing liquid heated to the decolorizing temperature into the first treatment tank. For example, it may be performed by previously preparing the decolorizing liquid heated to the decolorizing temperature in the first treatment tank and then introducing the object to be decolorized therein. Further, the heating step may be performed by simultaneously or sequentially introducing the object to be decolorized and the decolorizing liquid into the first treatment tank and heating the decolorizing liquid in the first treatment tank containing the object to be decolorized and the decolorizing liquid to the decolorizing temperature. In any case, the order of introducing the object to be decolorized and the decolorizing liquid into the first treatment tank may be either first.

[0034] In the stirring step, after the heating step or in parallel with the heating step (for example, after or during the contact of the decolorizing liquid with the fiber), the object to be decolorized and the decolorizing liquid are stirred in the first treatment tank. Thereby, it is expected that the pigment of the disperse dye is promoted to escape from the gaps between the molecular chains of the fiber loosened by heating.

[0035] (Rinsing step S2) In the rinsing step S2, the object to be decolorized is washed with the decolorizing liquid in the second treatment tank containing the decolorizing liquid at a temperature lower than the fiber opening temperature. In the rinsing step S2, a cooling step of cooling the object to be decolorized through the decolorizing liquid and a stirring step of stirring the object to be decolorized and the decolorizing liquid are mainly performed.

[0036] In the cooling step, the object to be decolorized after the decolorizing step S1 is cooled through the decolorizing liquid in the second treatment tank containing the decolorizing liquid at a temperature lower than the fiber opening temperature, for example, at room temperature or normal temperature (for example, about 20 °C or 25 °C). For example, in the first treatment tank, the object to be decolorized and the decolorizing liquid at a temperature lower than the fiber opening temperature are brought into contact with each other, and in particular, the fiber contained in the object to be decolorized and the decolorizing liquid at a temperature lower than the fiber opening temperature are brought into contact with each other. When the temperature of the object to be decolorized drops below the fiber opening temperature, the molecular chain structure of the polyester fiber or nylon fiber contained in the object to be decolorized is restored, so it is expected that the pigment of the disperse dye remaining on the surface of the object to be decolorized is prevented from being reabsorbed into the gaps between the molecular chains of the fiber.

[0037] The cooling step may be performed by simultaneously or sequentially introducing the object to be decolorized and the decolorizing liquid at a temperature below the fibrillation temperature into the first treatment tank. For example, it may be performed by previously preparing the decolorizing liquid at a temperature below the fibrillation temperature in the second treatment tank and then introducing the object to be decolorized therein, or by introducing the object to be decolorized into the second treatment tank and then adding the decolorizing liquid at a temperature below the fibrillation temperature to the second treatment tank.

[0038] In the stirring step, after the cooling step or in parallel with the cooling step (for example, after or during the contact of the decolorizing liquid with the fiber), the object to be decolorized and the decolorizing liquid are stirred in the second treatment tank. Thereby, the pigment of the disperse dye remaining on the surface of the object to be decolorized is more surely removed.

[0039] (Draining step S3) In the draining step S3, the object to be decolorized after the rinsing step S2 is taken out from the second treatment tank, and the decolorizing liquid is drained from the object to be decolorized. Draining can be performed, for example, by a centrifugal or squeezing type draining device (dehydrating device).

[0040] (Drying step S4) In the drying step S4, the drained object to be decolorized is dried. Drying can be performed, for example, by leaving the object to be decolorized at room temperature or normal temperature (25°C), press drying, blowing hot air, etc.

[0041] (Effects of the first embodiment) Conventionally, the decolorizing liquid was applied to the fiber cloth which was the object to be decolorized, the absorber was pressed against it from above, and heat pressing was applied to move the dye from the fiber cloth to the absorber, thereby decolorizing the fiber cloth. With this method, it was difficult to decolorize an object to be decolorized having a three-dimensional shape such as a stuffed toy. Also, since a large absorber is required in proportion to the area of the region to be decolorized, when the object to be decolorized becomes large, a large amount of the absorber becomes waste, which is uneconomical and has a high environmental load. Due to such uneconomy and environmental load, the size of the object to be decolorized was substantially limited.

[0042] On the one hand, according to the decolorization method of the present embodiment, the disperse dye can be decolorized from the object to be decolorized by washing the object to be decolorized with a decolorizing solution heated to a predetermined decolorization temperature. Therefore, in this decolorization method, the shape of the object to be decolorized is not limited to a plane, and three-dimensional products can also be decolorized. In addition, since this decolorization method does not require an absorber, even if the object to be decolorized is enlarged, no economic problems or environmental problems will occur, so there are no conventional restrictions on the size of the object to be decolorized. Therefore, according to this decolorization method, the object to be decolorized can be suitably decolorized without depending on the shape and size of the object to be decolorized.

[0043] (Modification 1-1) The decolorization step S1 can be realized by any method as long as the object to be decolorized is washed with a decolorizing solution at a decolorization temperature equal to or higher than the glass transition point of the polyester fiber or nylon fiber contained in the object to be decolorized and capable of dissolving the pigment of the disperse dye.

[0044] (Modification 1-1-1) In the first embodiment, in the decolorization step S1, a stirring step of stirring the object to be decolorized and the decolorizing solution is performed. However, as long as the pigment of the disperse dye can be decolorized from the object to be decolorized, a stimulation application step of applying mechanical stimulation to the object to be decolorized by a method other than stirring may be performed.

[0045] For example, shaking the decolorizing solution together with the object to be decolorized in the first treatment tank, performing ultrasonic treatment on the decolorizing solution together with the object to be decolorized in the first treatment tank, contacting the rotating blade with the object to be decolorized in the first treatment tank to stimulate it, etc. can be mentioned.

[0046] (Modification 1-1-2) In the first embodiment and the above-described modifications, in the decolorization step S1, a stirring step of stirring the object to be decolorized and the decolorizing solution or a stimulation application step of applying mechanical stimulation is performed. Instead of or in addition to this, a relative movement step of relatively moving the decolorizing solution with respect to the surface of the object to be decolorized may be performed. As a result, since the decolorizing solution moves relatively with respect to the object to be decolorized, a relatively fresh unused decolorizing solution is supplied to the surface of the object to be decolorized, and it is expected that the decolorization of the disperse dye will be promoted.

[0047] For example, in the decolorization step S1, instead of or together with the stirring step or the stimulation application step, a new or recycled decolorizing liquid may be supplied to the first treatment tank, and the excess decolorizing liquid may be discharged from the first treatment tank. As a result, a flow of the decolorizing liquid can be formed in the first treatment tank, so that the decolorizing liquid moves relative to the object to be decolorized. Further, in this case, the used decolorizing liquid discharged from the first treatment tank may be re-supplied to the first treatment tank. That is, the decolorizing liquid may be circulated. Further, in this case, the decolorizing liquid may be circulated while removing impurities, particularly disperse dyes, especially the pigments of disperse dyes, from the decolorizing liquid. The removal of impurities can be performed, for example, by filtration using activated carbon or the like or by distillation.

[0048] (Modification 1-1-3) In the first embodiment and the above-described modification, in the decolorization step S1, instead of a new decolorizing liquid, a used decolorizing liquid from which impurities, particularly disperse dyes, especially the pigments of disperse dyes, have been removed may be used.

[0049] For example, the waste liquid of the decolorizing liquid generated in the decolorization step S1 may be recovered every time the decolorization treatment is performed, impurities may be removed therefrom, and then it may be used in the next decolorization step S1 or the rinsing step S1.

[0050] Further, for example, the decolorization step S1 may be performed while circulating the decolorizing liquid through the first treatment tank while removing impurities from the decolorizing liquid. For example, in the decolorization step S1, the excess decolorizing liquid may be discharged from the first treatment tank, impurities may be removed from the discharged decolorizing liquid, and this decolorizing liquid may be supplied again to the first treatment tank.

[0051] (Modification 1-1-4) In the first embodiment, in the decolorization step S1, the object to be decolorized is washed with the decolorizing liquid in the first treatment tank in which the decolorizing liquid at a predetermined decolorization temperature is contained, but if the object to be decolorized can be washed with the decolorizing liquid at a predetermined decolorization temperature, it is not necessary to use a treatment tank.

[0052] For example, the decolorization step S1 can also be performed by spraying a decolorizing liquid onto the object to be decolorized as a liquid or a gas at the decolorization temperature. For example, the decolorizing liquid may be sprayed onto the object to be decolorized as vapor, droplets, or mist at the decolorization temperature by a steamer or an atomizer, particularly a high-pressure steamer or a high-pressure atomizer. Also by this method, since the object to be decolorized is heated, the same effect as the above-described heating step can be expected. Further, since the object to be decolorized is mechanically stimulated by the spraying of the decolorizing liquid, the same effects as the above-described stirring step and the stimulation application step can be expected. In particular, in order to enhance the mechanical stimulation applied to the object to be decolorized and the strength of the flow of the decolorizing liquid on the surface of the object to be decolorized, it is preferable to spray the vapor, droplets, or mist of the decolorizing liquid vigorously at high pressure. In other words, by spraying the decolorizing liquid onto the object to be decolorized as a liquid or a gas at the decolorization temperature, both the heating step of heating the object to be decolorized and the stimulation application step of applying mechanical stimulation to the object to be decolorized can be performed.

[0053] (Modification Example 1-1-5) In the first embodiment and the above-described modification examples, in the decolorization step S1, the heating step and the stirring step, the stimulation application step, or the relative movement step are performed. However, the stirring step, the stimulation application step, or the relative movement step may be omitted. In this case, in the heating step, the decolorization temperature may be increased and / or the time during which the object to be decolorized is in contact with the decolorizing liquid may be lengthened as compared with the case where these omitted steps are performed.

[0054] (Modification Example 1-2) The rinsing step S2 can be realized by any method as long as the decolorizing liquid at a temperature lower than the fibrillation temperature is brought into contact with the object to be decolorized (particularly, the fiber of the object to be decolorized).

[0055] (Modification Example 1-2-1) The rinsing step S2 can be performed in the same manner as the decolorization step S1 except that a cooling step is performed instead of the heating step. Therefore, except for the point that a cooling step is performed instead of the heating step, the above-described modification examples regarding the decolorization step S1 are also applicable to the rinsing step S2.

[0056] In addition, in the rinsing step S2, when the stirring step, the stimulation application step, or the relative movement step is omitted, the time during which the object to be decolorized is in contact with the decolorizing solution in the cooling step may be made longer than when these omitted steps are performed.

[0057] Also, the method of applying mechanical stimulation to the object to be decolorized in the decolorization step S1 and the rinsing step S1 may be the same or different, and the stirring step and the stimulation application step may be omitted in one or both of them. The same applies to the method of relatively moving the decolorizing solution with respect to the object to be decolorized in the decolorization step S1 and the rinsing step S1.

[0058] (Modification Example 1-2-2) In the first embodiment and the above-described modification examples, the decolorization step S1 and the rinsing step S2 are performed in separate treatment tanks, but they may be performed in the same treatment tank. For example, after the decolorization step S1, the decolorizing solution may be discharged from the first treatment tank, a new decolorizing solution at a temperature lower than the fibrillation temperature may be poured into the first treatment tank, and then the stirring step, the stimulation application step, or the relative movement step may be performed.

[0059] (Modification Example 1-2-3) Also, if the object to be decolorized is sufficiently decolorized in the decolorization step S1, the rinsing step S2 may be omitted.

[0060] (Modification Example 1-3) The decolorization step S1 and / or the rinsing step S2 may be performed multiple times.

[0061] (Modification Example 1-4) In the first embodiment and the above-described modification examples, the same type of liquid, for example, a decolorizing solution having the same composition, is used in the decolorization step S1 and the rinsing step S2, but decolorizing solutions having different compositions may also be used. For example, the decolorizing solution used in the rinsing step S2 may contain the same solvent for dissolving the pigment of the disperse dye as the decolorizing solution used in the decolorization step S1 at different concentrations.

[0062] Also, when the decolorization step S1 is performed multiple times, the decolorizing liquids used in each decolorization step S1 may all be the same, or some or all of them may be different. The same applies when the rinsing step S2 is performed multiple times or when both the decolorization step S1 and the rinsing step S2 are performed multiple times.

[0063] (Modification Example 1-5) Furthermore, since the decolorization of the disperse dye pigment from the object to be decolorized is completed by both the decolorization step S1 and the rinsing step S2 or only by the decolorization step S1, the liquid removal step S3 and the drying step S4 may be performed as necessary, and one or both of the liquid removal step S3 and the drying step S4 may be omitted. For example, when the entire object to be decolorized is re-dyed by the exhaustion dyeing method after decolorization, the liquid removal step S3 and the drying step S4 may be omitted, and dehydration and drying may be performed only once after dyeing.

[0064] (Modification Example 1-6) In the first embodiment and the above-described modification, the pigment of the disperse dye dyed or colored on the object to be decolorized is decolorized from the polyester fiber or nylon fiber contained in the object to be decolorized with a decolorizing liquid that dissolves the pigment of the dye. However, instead of the disperse dye, other dyes dyed or colored on the object to be decolorized may be decolorized, or instead of the polyester fiber or nylon fiber, dyes may be decolorized from other fibers that hold the pigments of disperse dyes or other dyes in the gaps between the molecular chains of the fibers in the same manner as these fibers. The decolorizing liquid may be any decolorizing liquid that can decolorize the pigments of such dyes from such fibers. Further, for example, the decolorizing liquid may contain a bleaching agent that bleaches the pigment of the dye (for example, decomposes and removes the pigment or discolors it to make the pigment less noticeable (for example, approaching the color of the fiber, particularly white)), and particularly, it may be a bleaching liquid. Examples of such bleaching agents include oxidative bleaching agents (for example, chlorine-based bleaching agents or oxygen-based bleaching agents) and reducing bleaching agents. Further, when the decolorizing liquid contains a bleaching agent, particularly when the bleaching agent is a bleaching agent that discolors the pigment to make it less noticeable, the fiber opening temperature may be a temperature at which the molecular chain of the fiber relaxes until the gap between the molecular chains of the fiber where the pigment of the dye exists becomes wide enough for the active ingredient of the bleaching agent to easily access the pigment. Therefore, the fiber opening temperature may be a temperature at which the molecular chain of the fiber contained in the object to be decolorized relaxes.

[0065] (Second Embodiment) The decolorizing device 100 according to the second embodiment of the present invention will be described. According to the decolorizing device 100, the decolorizing method according to the first embodiment can be preferably performed.

[0066] (Configuration of Decolorizing Device 100) As shown in FIGS. 2 and 3, the decolorizing device 100 includes a sealed housing 10, a conveying unit 20, a decolorizing unit 30, a rinsing unit 40, an exhaust device 50, a fume recovery device 60, and a control unit 70.

[0067] The sealed housing 10 houses a conveyance unit 20, a decolorization unit 30, and a rinsing unit 40, and is designed to be airtight so that fumes generated from the decolorization unit 30 and the rinsing unit 40 do not leak to the outside through any route other than a predetermined route such as an exhaust device 50. The sealed housing 10 includes an inlet 11 that is opened when loading the object to be decolorized 1 scheduled for decolorization into the sealed housing 10, and an outlet 12 that is opened when unloading the object to be decolorized 1 after decolorization from the sealed housing 10.

[0068] The conveyance unit 20 conveys the object to be decolorized 1 through the decolorization process. The conveyance unit 20 includes a rail 21 that passes above a predetermined position where a transport box 5 in which the object to be decolorized 1 scheduled for decolorization is folded and stored is placed, above the decolorization unit 30 and the rinsing unit 40, and above a predetermined position where a collection box 6 for collecting the object to be decolorized 1 after decolorization is placed, a robot base 22 that moves on the rail 21, and a robot arm 23 that is provided on the robot base 22 and can grip the object to be decolorized 1.

[0069] The decolorization unit 30 washes the object to be decolorized with the decolorizing liquid 2 in a treatment tank filled with the decolorizing liquid 2 at a predetermined decolorization temperature. As shown in FIG. 4, the decolorization unit 30 includes a first treatment tank 31, a first storage tank 32, a first supply piping system 33, a first waste liquid tank 34, a first discharge piping system 35, a first impurity removal device 36, and a heating device 37.

[0070] The first treatment tank 31 includes a cylindrical outer tank 31a with an open top, a cylindrical inner tank 31b with an open top housed inside the outer tank 31a, and a motor 31c disposed below the outer tank 31a and the inner tank 31a to drive the inner tank 31b. The outer tank 31a and the inner tank 31b are made of stainless steel. The outer tank 31a is in fluid communication with the first storage tank 32 via the first supply piping system 33 and is also in fluid communication with the first waste liquid tank 34 via the first discharge piping system 35. During the decolorization process, the inside of the outer tank 31a is filled with the decolorizing liquid 2 supplied from the first storage tank 32 via the first supply piping system 33. The inner tank 31b has a plurality of through-holes through which the decolorizing liquid 2 passes. During the decolorization process, the inner tank 31b is filled with the decolorizing liquid 2 that has entered through the through-holes, and the object to be decolorized 1 is introduced by the conveying unit 20. The motor 31c is connected to the center of the bottom of the inner tank 31b by a drive shaft that penetrates the center of the bottom of the outer tank 31a in a watertight manner. The motor 31c rotates the inner tank 31b about a vertical axis passing through the center of the bottom of the inner tank 31b during the decolorization process. Thereby, the object to be decolorized 1 and the decolorizing liquid 2 in the first treatment tank 31 are stirred.

[0071] The first storage tank 32 stores the decolorizing liquid 2 and supplies the decolorizing liquid 2 to the first treatment tank 31 via the supply piping system 33.

[0072] The first supply piping system 33 includes a supply pipe 33a through which the decolorizing liquid 2 supplied to the first treatment tank 31 passes, a supply valve 33b which is an electromagnetic valve for controlling the supply of the decolorizing liquid 2 to the first treatment tank 31, and a supply pump 33c for supplying the decolorizing liquid 2.

[0073] The first waste liquid tank 34 stores the used decolorizing liquid 2 discharged from the first treatment tank 31 via the first discharge piping system 35.

[0074] The first discharge piping system 35 includes a discharge pipe 35a through which the used decolorizing liquid 2 discharged from the first treatment tank 31 passes, and a discharge valve 35b which is an electromagnetic valve for controlling the discharge of the decolorizing liquid 2 from the first treatment tank 31.

[0075] The first impurity removal device 36 is an activated carbon filtration device that removes disperse dyes, particularly their pigments, from the decolorized liquid 2 in which the disperse dyes discharged from the first treatment tank 31 are dissolved. The activated carbon filter of the first impurity removal device 36 is of a cartridge type and can be replaced as needed or periodically.

[0076] The heating device 37 heats the decolorized liquid 2 in the first treatment tank 31 to the decolorization temperature. The heating device 36 is an induction heating (IH) heater or a radiant heater arranged to surround the side surface of the cylindrical outer tank 31a of the first treatment tank 31.

[0077] The rinsing section 40 washes the object to be decolorized with the decolorized liquid in a treatment tank filled with the decolorized liquid at a temperature below a predetermined fiber opening temperature, for example, room temperature or normal temperature (e.g., about 20 °C or 25 °C). As shown in FIG. 5, the rinsing section 40 includes a second treatment tank 41, a second storage tank 42, a second supply piping system 43, a second waste liquid tank 44, a second discharge piping system 45, and a second impurity removal device 46. The configurations of the second treatment tank 41, the second storage tank 42, the second supply piping system 43, the second waste liquid tank 44, the second discharge piping system 45, and the second impurity removal device 46 are the same as those of the first treatment tank 31, the first storage tank 32, the first supply piping system 33, the first waste liquid tank 34, the first discharge piping system 35, and the first impurity removal device 36, respectively, and thus the description is omitted.

[0078] The exhaust device 50 exhausts the fumes of the decolorized liquid 2 generated from the decolorization section 30 and the rinsing section 40. The exhaust device 50 includes an exhaust duct 51 and an exhaust fan 52.

[0079] The fume recovery device 60 is arranged in the middle of the exhaust duct 51 of the exhaust device 50 and returns the fumes of the decolorized liquid 2 passing through the exhaust device 50 to a liquid for recovery. The fume recovery device 60 includes an electronic cooler that condenses the fumes on its surface and a recovery tank that recovers the condensate dripping from the surface of the electronic cooler.

[0080] The control unit 70 controls the conveyance unit 20, the decolorization unit 30, the rinsing unit 40, the exhaust device 50, and the fume recovery device 60 to perform a decolorization process for decolorizing the object to be decolorized 1 with the decolorizing liquid 2 and a recovery process for recovering the decolorizing liquid 2.

[0081] To perform the process, the control unit 70 includes a storage device (such as a hard disk or a flash memory) that stores programs and various data, a processor (such as a CPU (Central Processing Unit)) that executes the programs stored in the storage device and actually executes the printing process by using the various data, a main memory of the processor, and various interfaces. The control unit 70 may be, for example, a personal computer.

[0082] (Decolorization process) First, when the carrier box 5 in which the object to be decolorized 1 scheduled for decolorization is folded and stored is carried into a predetermined position outside the sealed housing 10 by an automatic supply device such as an operator or a self-propelled wagon, the control unit 70 controls the conveyance unit 20 to move the robot base 22 above the carrier box 5, lift one or more objects to be decolorized 1 in the carrier box 5 onto the robot arm 23, move the robot base 22 above the first treatment tank 31 of the decolorization unit 30, and drop the object to be decolorized 1 held by the robot arm 23 downward. In this way, the object to be decolorized 1 is put into the first treatment tank 31 of the decolorization unit 30. At this time, the control unit 70 controls the opening / closing mechanism of the inlet 11 of the sealed housing 10 to open the inlet 11 when the robot arm 23 of the conveyance unit 20 passes through the inlet 11 and close it after passing through.

[0083] When the object to be decolorized 1 is put into the first treatment tank 31, the control unit 70 controls the supply valve 33b and the supply pump 33c of the first supply piping system 33 of the decolorization unit 30 to fill the inside of the first treatment tank 31 with the decolorizing liquid 2. Then, the control unit 70 controls the heating device 37 to heat the decolorizing liquid in the first treatment tank 31 to a predetermined decolorization temperature. Then, the motor 31c of the first treatment tank 31 is controlled to rotate the first inner tank 31b for a predetermined time. Thereby, the object to be decolorized 1 and the decolorizing liquid 2 are stirred.

[0084] After the rotation of the first inner tank 31b of the first treatment tank 31 stops, the control unit 70 controls the transfer unit 20 to cause the robot arm 23 to take out the object 1 to be decolorized from the first treatment tank 31, move the robot base 22 above the second treatment tank 41 of the rinsing unit 40, and cause the robot arm 23 to drop the object 1 to be decolorized that it holds downward. In this way, the object 1 to be decolorized is put into the second treatment tank 41 of the rinsing unit 40.

[0085] When the object 1 to be decolorized is put into the second treatment tank 41, the control unit 70 controls the supply valve 43b and the supply pump 43c of the second supply piping system 43 of the rinsing unit 40 to fill the inside of the second treatment tank 41 with the decolorizing liquid 2 at room temperature or normal temperature. Then, the control unit 70 controls the motor 41c of the second treatment tank 41 to rotate the second inner tank 41b for a predetermined time. Thereby, the object 1 to be decolorized and the decolorizing liquid 2 are stirred.

[0086] After the rotation of the second inner tank 41b of the second treatment tank 41 stops, the control unit 70 controls the transfer unit 20 to cause the robot arm 23 to take out the object 1 to be decolorized from the second treatment tank 41, move the robot base 22 above the collection box 6 at a predetermined position outside the sealed housing 10, and cause the robot arm 23 to drop the object 1 to be decolorized that it holds downward. In this way, the decolorized object 1 to be decolorized is put into the collection box 6. At this time, the control unit 70 controls the opening / closing mechanism of the outlet 12 of the sealed housing 10 to open the outlet 12 when the robot arm 23 of the transfer unit 20 passes through the outlet 12 and close it after passing through.

[0087] Thereafter, the collection box 6 containing the decolorized object 1 to be decolorized is transported to the liquid removal device by an automatic supply device such as an operator or a self-propelled wagon, and the object 1 to be decolorized is de-liquefied by the liquid removal device. Thereafter, the de-liquefied object 1 to be decolorized is transported to the drying device by an automatic supply device such as an operator or a self-propelled wagon, and the object 1 to be decolorized is dried by the drying device.

[0088] (Recovery process) First, in the above-described decolorization treatment, when the object 1 to be decolorized is taken out from the first treatment tank 31, the control unit 70 controls the first discharge piping system 35 of the decolorization unit 30 to discharge the decolorizing liquid 2 from the first treatment tank 31 to the first waste liquid tank 34. In this process, the used decolorizing liquid 2 passing through the first discharge piping system 35 has disperse dyes, particularly their pigments, removed by the first impurity removal device 36.

[0089] Also, in the above-described decolorization treatment, when the object 1 to be decolorized is taken out from the second treatment tank 41, the control unit 70 controls the second discharge piping system 45 of the rinsing unit 40 to discharge the decolorizing liquid 2 from the second treatment tank 41 to the second waste liquid tank 44. In this process, the used decolorizing liquid 2 passing through the second discharge piping system 45 has disperse dyes, particularly their pigments, removed by the second impurity removal device 46.

[0090] Further, during the above-described decolorization treatment, the control unit 70 controls the exhaust fan 52 of the exhaust device 50 to discharge the fumes of the decolorizing liquid 2 generated from the decolorization unit 30 and the rinsing unit 40 to the outside through the exhaust duct 51. Also, in this process, the control unit 70 controls the electronic cooler of the fume recovery device 60 to cause the fumes passing through the exhaust duct 51 to condense on the surface of the electronic cooler. Thus, the condensed decolorizing liquid 2 drips from the surface of the electronic cooler and is finally recovered in the recovery tank of the fume recovery device 60.

[0091] The decolorizing liquid 2 recovered in the first waste liquid tank 34 of the decolorization unit 30, the second waste liquid tank 44 of the rinsing unit, and the recovery tank of the fume recovery device 60 all contain no impurities, particularly disperse dyes, especially the pigments of disperse dyes, or only contain them to an extent that does not pose a problem for decolorization, so they can be reused in subsequent decolorization treatments.

[0092] (Effect of the Second Embodiment) The decolorization device according to the second embodiment first exhibits the same effects as the decolorization method according to the first embodiment.

[0093] In addition, processes such as the decolorization step S1 and the rinsing step S2 in which fumes of the decolorizing liquid 2 that may be harmful are generated can be automatically performed in a closed environment without manual labor. As a result, the object to be decolorized can be decolorized without imposing a burden on the user (particularly, a labor or health burden).

[0094] Further, since the decolorizing liquid 2 recovered in the first waste liquid tank 34 of the decolorizing unit 30, the second waste liquid tank 44 of the rinsing unit, and the recovery tank of the fume recovery device 60 can be reused, the environmental load and the economic load are reduced.

[0095] (Modification Example 2-1) The configuration of the decolorizing device 100, particularly the configuration of the decolorizing unit 30, is arbitrary as long as the decolorization step S1 of the first embodiment and its modification can be executed.

[0096] For example, in the second embodiment, the first treatment tank 31 is composed of a cylindrical outer tank 31a and an inner tank 31b, but the first treatment tank 31 is not limited to this. For example, the first treatment tank 31 may include only the outer tank 31a without the inner tank 31b. Further, the shape of the first treatment tank 31 is not limited to a cylindrical shape, and other shapes, for example, a rectangular shape may be used. For example, as the first treatment tank 31, a box-shaped treatment tank with an open upper part of a deep or shallow type may be used. Further, the material of the first treatment tank 31 is not limited to stainless steel, and other materials, for example, glass, heat-resistant and solvent-resistant resin may be used.

[0097] Further, the impurity removal device 36 may be omitted. In this case, the decolorizing liquid 2 stored in the first waste liquid tank 34 may be carried out of the sealed housing 10 and subjected to regeneration treatment such as filtration or distillation.

[0098] (Modification Example 2-1-1) In the second embodiment, in the decolorizing unit 30, the inner tank 31b of the first treatment tank 31 is rotated to stir the object to be decolorized 1 and the decolorizing liquid 2, but as long as the pigment of the disperse dye can be removed from the object to be decolorized 1, a stirring method other than this stirring method may be used, or a mechanical stimulus may be applied to the object to be decolorized 1 by a method other than stirring.

[0099] For example, as a stirring device using another stirring method, there is a motor-driven stirring blade provided on the bottom surface of the outer tank 31a or the inner tank 31b of the first treatment tank 31. Further, it is also possible to arrange a stirrer, for example, a magnetic stirrer or an electromagnetic stirrer at the bottom of at least one of these treatment tanks to perform stirring. Further, it is also possible to generate convection by vibrating the entire body of these treatment tanks or by using a pump.

[0100] Further, for example, as a stimulating device that applies a mechanical stimulus to the object to be decolorized 1, there are a shaking device that shakes the decolorizing liquid 2 together with the object to be decolorized 1 in the first treatment tank 31, an ultrasonic treatment device that performs ultrasonic treatment on the decolorizing liquid 2 together with the object to be decolorized 1 in the first treatment tank 31, and a motor-driven stirring blade that is arranged so as to come into contact with the object to be decolorized 1 in the first treatment tank 31.

[0101] (Modification Example 2-1-2) In the second embodiment and the above-described modification examples, in the decolorization unit 30, the object to be decolorized 1 and the decolorizing liquid 2 are stirred or mechanically stimulated. Instead of or in addition to this, the decolorizing liquid 2 may be relatively moved with respect to the surface of the object to be decolorized 1.

[0102] For example, in the second embodiment, the decolorization unit 30 discharges the decolorizing liquid 2 in the first treatment tank 31 every time the decolorization treatment is completed, and supplies and stores new decolorizing liquid 2 in the first treatment tank 31 for the next decolorization treatment. However, new or recovered and reused decolorizing liquid 2 may be supplied to the first treatment tank 31, and the decolorization treatment may be performed while discharging excess decolorizing liquid 2 from the first treatment tank 31. Further, in this case, the used decolorizing liquid 2 discharged from the first treatment tank 31 may be re-supplied to the first treatment tank 31. That is, the decolorizing liquid 2 may be circulated. For this purpose, for example, the first discharge piping system 35 may be connected to the first supply tank 32 instead of the first waste liquid tank 34, or the first treatment tank 31 and the first supply tank 32 may be connected by another discharge piping system. Further, in this case, in order to improve the flow of the decolorizing liquid 2, an impurity removal device may not be provided in the first discharge piping system 35 or another discharge piping system.

[0103] Also, for example, in order to cause relative movement of the decolorizing liquid 2 with respect to the surface of the object 1 to be decolorized, one or more nozzles for ejecting the decolorizing liquid 2 along the normal direction of the outer peripheral circle of the vortex to be formed may be provided in the first treatment tank 31 so as to form a vortex. For example, in the case of the second embodiment, one or more nozzles for ejecting the decolorizing liquid 2 obliquely from the center of the circular bottom of the outer tank 31a toward the side surface of the outer tank 31a may be provided in the cylindrical outer tank 31a of the first treatment tank 31 when viewed from above. The decolorizing liquid 2 is supplied to these nozzles from the first supply piping system 33. When the decolorizing liquid 2 is supplied into the first treatment tank 31 in this way, a vortex flow is generated in the first treatment tank 31, which causes relative movement of the decolorizing liquid 2 with respect to the surface of the object 1 to be decolorized.

[0104] Also, for example, when using a box-shaped treatment tank with an open upper part of a deep or shallow type as the first treatment tank 31, in order to cause relative movement of the decolorizing liquid 2 with respect to the surface of the object 1 to be decolorized, the first supply piping system 33 may be opened at one end in the major axis direction of the box-shaped treatment tank so that the decolorizing liquid 2 flows from one end to the other end, and the first discharge piping system 35 may be opened at the other end.

[0105] (Modification Example 2-1-3) In the second embodiment and the above-described modification example, in the decolorization unit 30, instead of the new decolorizing liquid 2, a used decolorizing liquid 2 from which impurities, particularly disperse dyes, especially the pigments of disperse dyes, have been removed may be used.

[0106] For example, the waste liquid of the decolorizing liquid 2 generated in the decolorization unit 30 may be collected every time a decolorization process is performed, impurities may be removed, and then it may be used in the decolorization unit 30 or the rinsing unit 40 in the next decolorization process. For example, in order to automatically perform such reuse, as shown in FIG. 6, in the first supply piping system 33, a supply pipe 33d branched upstream of the supply pump 33c from the supply pipe 33a is connected to the first waste liquid tank 34, a supply valve 33e is provided between the first supply tank 32 and the above-described branch, and a supply valve 33f is provided between the first waste liquid tank 34 and the above-described branch. In this case, when using the new decolorizing liquid 2, the supply valves 33b and 33e are opened, the supply valve 33f is closed, and the supply pump 33c is operated to supply the decolorizing liquid 2 from the first supply tank 32 to the first treatment tank 31. On the other hand, when using the decolorizing liquid 2 from which impurities have been removed, the supply valves 33b and 33f are opened, the supply valve 33e is closed, and the supply pump 33c is operated to supply the decolorizing liquid 2 from the first waste liquid tank 34 to the first treatment tank 31.

[0107] Further, for example, the decolorization step S1 may be performed while circulating the decolorizing liquid through the first treatment tank while removing impurities from the decolorizing liquid. For example, in the decolorization step S1, excess decolorizing liquid may be discharged from the first treatment tank, impurities may be removed from the discharged decolorizing liquid, and this decolorizing liquid may be supplied again to the first treatment tank.

[0108] (Modification Example 2-1-4) Also, for example, instead of the first treatment tank 31, the decolorization unit 30 may include a spraying device that sprays the decolorizing liquid 2 as a liquid or gas onto the object to be decolorized 1 at the decolorization temperature. Examples of the spraying device include a steamer or an atomizer, particularly a high-pressure steamer or a high-pressure atomizer. In this case, the first piping supply system 33 is connected to such a spraying device, and the first discharge piping system 35 is connected to a waste liquid port under the floor instead of the first treatment tank 31. For example, the decolorizing liquid 2 is sprayed as a liquid or gas from the spraying device onto the object to be decolorized 1 held by the robot arm 23 of the transport unit 20. Drops of the decolorizing liquid 2 that drip from the object to be decolorized 1 are discarded from the waste liquid port and stored in the first waste liquid tank 34.

[0109] (Modification Example 2-1-5) In the second embodiment and the above-described modification examples, the decolorization unit 30 is configured to stir the object to be decolorized 1 and the decolorizing liquid 2, apply mechanical stimulation to the object to be decolorized 1, or relatively move the decolorizing liquid 2 with respect to the object to be decolorized 1, but such a configuration may be omitted. In this case, when the decolorization unit 30 performs the heating step of the decolorization step S1, the decolorization temperature may be increased and / or the time during which the object to be decolorized 1 is in contact with the decolorizing liquid 2 may be lengthened compared to the case where these omitted configurations are present.

[0110] (Modification Example 2-1-6) In the second embodiment and the above-described modification examples, the impurity removal device 36 is optional as long as it can remove disperse dyes, particularly the pigments thereof, from the used decolorizing liquid 2 discharged from the decolorization unit 30 to such an extent that the decolorizing liquid 2 can be reused for the decolorization treatment. In addition to the activated carbon filtration device, for example, a distillation device may also be used.

[0111] (Modification Example 2-1-7) In the second embodiment and the above-described modification examples, the configuration of the heating device 36 is optional as long as it can heat the decolorizing liquid 2 to the decolorization temperature. In addition to an induction heating (IH) heater or a radiant heater, for example, an oil bath or a plunge heater may also be used. Further, the heating device 36 may be arranged to heat the first supply tank 32 instead of or in addition to the first treatment tank 31 or the spraying device.

[0112] (Modification Example 2-1-8) In the second embodiment and the above-described modification examples, a lid configured to automatically open and close may be provided on the first treatment tank 31 of the decoloring unit 30. This lid is opened when the object 1 to be decolorized is placed in the first treatment tank 31, and is closed until the decoloring treatment in the decoloring unit 30 is completed. Thereby, the amount of fumes leaking from the first treatment tank 31 of the decoloring unit 30 can be reduced.

[0113] (Modification Example 2-2) The configuration of the rinsing unit 40 is arbitrary as long as it can execute the rinsing step S2 of the first embodiment and its modification examples.

[0114] (Modification Example 2-2-1) The rinsing unit 40 can be configured in the same manner as the decoloring unit 30 except for the temperature of the decoloring solution and the presence or absence of the heating device 36. Therefore, except for the temperature of the decoloring solution and the presence or absence of the heating device 36, the above-described modification examples regarding the decoloring unit 30 can also be applied to the rinsing unit 40.

[0115] In addition, in the rinsing unit 40, when the configuration of stirring the object 1 to be decolorized and the decoloring solution 2, applying a mechanical stimulus to the object 1 to be decolorized, or relatively moving the decoloring solution 2 with respect to the object 1 to be decolorized is omitted, when the rinsing unit 40 performs the cooling step of the rinsing step S2, the time during which the object 1 to be decolorized is in contact with the decoloring solution 2 may be made longer than in the case where these omitted configurations are present.

[0116] Also, the method of applying a mechanical stimulus to the object 1 to be decolorized in the decoloring unit 30 and the rinsing unit 40 may be the same, may be different, or one or both of them may omit the configuration of stirring the object 1 to be decolorized and the decoloring solution 2, applying a mechanical stimulus to the object 1 to be decolorized, or relatively moving the decoloring solution 2 with respect to the object 1 to be decolorized.

[0117] (Modification Example 2-2-2) Further, the rinsing section 40 may be provided with a cooling device that cools one or both of the second treatment tank 41 and the second storage tank 42. Thereby, the decolorizing liquid 2 in the rinsing section 40, which has become hot due to the frequently introduced decolorization target object 1 wetted with the heated decolorizing liquid 2, can be cooled. Thereby, the efficiency of decolorization in the rinsing section 40 can be maintained.

[0118] (Modification 2-2-3) Instead of or in addition to the rinsing section 40, the rinsing step S2 may be performed in the decolorizing section 30.

[0119] For example, after the decolorizing section 30 performs the decolorizing step S1, the decolorizing liquid 2 is discharged from the first treatment tank 31, and then, after supplying a decolorizing liquid at a temperature lower than the fibrillation temperature from the first storage tank 32, the decolorizing section 30 may be made to perform a stirring step, a stimulation application step, or a relative movement step.

[0120] (Modification 2-1-4) Also, if the decolorization target object is sufficiently decolorized in the decolorizing section 30, the rinsing section 40 may be omitted.

[0121] (Modification 2-3) A plurality of decolorizing sections 30 and / or rinsing sections 40 may be provided. For example, in order to increase the processing amount per unit time, the decolorizing step S1 may be performed in parallel in a plurality of decolorizing sections 30, or in order to perform decolorization more completely, the same decolorization target object 1 may be sequentially processed in a plurality of decolorizing sections 30. The same applies to the rinsing section 40.

[0122] (Modification 2-4) In the second embodiment and the above-described modifications, the decolorizing liquid 2 having the same composition is used in the decolorizing section 30 and the rinsing section 40, but decolorizing liquids 2 having different compositions may be used. For example, the decolorizing liquid used in the rinsing section 40 may contain the same solvent for dissolving the pigment of the disperse dye as the decolorizing liquid 2 used in the decolorizing section 30, but at different concentrations.

[0123] Also, when providing a plurality of decolorizing units 30, the decolorizing liquid 2 used in each decolorizing unit 30 may all be the same, or some or all of them may be different. The same applies when providing a plurality of rinsing units 40, or when providing both the decolorizing unit 30 and the rinsing unit 40 a plurality of times.

[0124] (Modification Example 2-5) The configuration of the sealed housing 10 is arbitrary as long as it is designed in a sealed manner so that the fumes generated from the decolorizing unit 30 and the rinsing unit 40 do not leak to the outside through paths other than a predetermined path such as the exhaust device 50.

[0125] For example, the inlet 11 and the outlet 12 of the sealed housing 10 are configured so that fumes do not leak from the inlet 11 and the outlet 12 or the amount of leakage is suppressed when the transport unit 20 transports the object to be decolorized 1. The inlet 11 and the outlet 12 may be provided with, for example, an air curtain.

[0126] (Modification Example 2-6) Instead of the sealed housing 10, as shown in FIG. 7, a hood 80 may be provided which is arranged above the openings from which the fumes of the decolorizing unit 30 and the rinsing unit 40 emerge and covers the openings. With this configuration as well, processes such as the decolorizing step S1 and the rinsing step S2 in which fumes of the decolorizing liquid 2 which may be harmful are generated can be automatically performed without manual intervention while not diffusing the fumes to the surroundings or reducing the amount of diffusion, so that the object to be decolorized can be decolorized without imposing a burden on the user.

[0127] Also, in order to shorten the distance between the hood 80 and the openings from which the fumes of the decolorizing unit 30 and the rinsing unit 40 emerge, as shown in FIG. 7, the transport unit 20 may be arranged on the side of the hood 80 and configured to access the openings of the decolorizing unit 30 and the rinsing unit 40 from the gap between the hood 80 and the decolorizing unit 30 and the rinsing unit 40.

[0128] Also, the hood 80 may be individually arranged above the decolorizing unit 30, the rinsing unit 40, or other devices that may generate harmful substances.

[0129] (Modification Example 2-7) The configuration of the exhaust device 50 is arbitrary as long as it can exhaust the fumes of the decolorizing liquid 2 generated from the decolorizing section 30 and the rinsing section 40.

[0130] (Modification Example 2-8) The configuration of the fume recovery device 60 is arbitrary as long as it can return the fumes of the decolorizing liquid 2 passing through the exhaust device 50 to a liquid and recover them. For example, if the fumes of the decolorizing liquid 2 condense on the inner surface of the exhaust duct 51 of the exhaust device 50, the bottom of the horizontally extending portion of the exhaust duct 51 is provided in a funnel shape, and the tip of the funnel is connected to a recovery device such as a recovery bottle by a drain, so that the fumes can be returned to a liquid and recovered.

[0131] (Modification Example 2-9) One or both of the liquid removal device and the drying device may be provided inside the sealed housing 10, or may be provided under the hood 80. Also, other devices required for the pretreatment and post-treatment of decolorization may be provided inside the sealed housing 10, or may be provided under the hood 80.

[0132] (Modification Example 2-10) The configuration of the conveyance unit 20 is arbitrary as long as it can put the object to be decolorized 1 into and take it out of the decolorizing section 30 and the rinsing section 40. For example, a configuration such as a work holding mechanism that is attached to a turntable and can move up and down, or a tenter clip, can be adopted. Also, when the liquid removal device, the drying device, or other devices are provided inside the sealed housing 10 or under the hood 80, the conveyance unit 20 may be configured to convey the object to be decolorized 1 to those devices and apply the object to be decolorized 1 to those devices.

[0133] (Modification Example 2-11) The decolorizing device 100 is configured with an explosion-proof specification.

[0134] (Example 1) A test pattern of a color chart was printed on a 60 cm × 60 cm polyester fabric (Tropical (product name)) using a direct sublimation printing device (Mimaki Engineering Co., Ltd., Tiger600-1800TS (product name)) with a disperse dye (Mimaki Engineering Co., Ltd., Sb510 (product name)). This polyester fabric was immersed in New Solv UC in a liquid tank and heated for 2 minutes while stirring the solution with a stirrer (100 rpm) up to 160°C. Then, this polyester fabric was immersed in New Solv UC (the main components are dimethyl succinate, dimethyl glutarate, and dimethyl adipate) in another beaker and heated for 10 seconds while stirring the solution with a stirrer (100 rpm) up to 160°C. Finally, the polyester fabric was taken out, de-liquored, and dried. The test pattern completely disappeared from the decolorized polyester fabric, and there was no deterioration in texture or shrinkage.

[0135] (Example 2) A decolorization treatment was performed in the same manner as in Example 1, except that ethyl acetate diethylene glycol was used instead of New Solv UC. Also in this case, the test pattern completely disappeared from the decolorized polyester fabric, and there was no deterioration in texture or shrinkage.

[0136] (Example 3) A decolorization treatment was performed in the same manner as in Example 1, except that 3-methoxy-N,N-dimethylpropanamide was used instead of New Solv UC. Also in this case, the test pattern completely disappeared from the decolorized polyester fabric, and there was no deterioration in texture or shrinkage.

[0137] The present disclosure can be implemented in various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Also, the above-described embodiments are for explaining the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is shown not by the embodiments but by the claims. And various modifications made within the scope of the claims and within the scope of the meaning equivalent to the disclosure are considered to be within the scope of the present disclosure.

Explanation of Reference Numerals

[0138] 1 Object to be decolorized 2 Decolorizing liquid 5 Transport box 6 Recycling box 10 Sealed housing 11 Inlet 12 Outlet 20 Conveyor section 21 Rail 22 Robot base 23 Robot arm 30 Decolorizing section 31 First treatment tank 32 First storage tank 33 First supply piping system 33a First supply pipe 33b, 33d Supply valves 33c, 33e, 33f Supply pumps 34 First waste liquid tank 35 First discharge piping system 35a Discharge pipe 35b Discharge valve 36 First impurity removal device 37 Heating device 40 Rinsing section 41 Second treatment tank 42 Second storage tank 43 Second supply piping system 43a Supply pipe 43b Supply valve 43c Supply pump 44 Second waste liquid tank 45 Second discharge piping system 45a Discharge pipe 45b Discharge valve 46 Second impurity removal device 50 Exhaust device 51 Exhaust duct 52 Exhaust fan 60 Fume recovery device 70 Control section 80 Hood 100 Decolorizing device

Claims

1. A decolorization method for decolorizing a dye pigment from a decolorization target containing fibers dyed or colored with a dye, wherein the pigment is held in gaps between molecular chains of the fibers, a decolorization step of washing the decolorization target with a first decolorization liquid having a decolorization temperature equal to or higher than an opening temperature at which the molecular chains are loosened to such an extent that the pigment escapes from the gaps between the molecular chains of the fibers contained in the decolorization target, comprising: a decolorization method.

2. The dye is a disperse dye, and the fiber is a fiber that can be dyed or colored with the disperse dye, The decolorization method according to claim 1.

3. In the decolorization step, the fibers are brought into contact with the first decolorization liquid having the decolorization temperature in a treatment tank, The decolorization method according to claim 1.

4. In the decolorization step, the decolorization target is carried into the first decolorization liquid in the treatment tank containing the first decolorization liquid heated to the decolorization temperature, The decolorization method according to claim 3.

5. In the decolorization step, the first decolorization liquid is heated to the decolorization temperature in the treatment tank containing the decolorization target and the first decolorization liquid below the decolorization temperature, The method according to claim 3.

6. The decolorization step includes a stimulation application step of applying mechanical stimulation to the decolorization target after or during contact of the first decolorization liquid with the fibers, The decolorization method according to claim 3.

7. The stimulation application step includes any one of a step of stirring the first decolorization liquid containing the decolorization target in the treatment tank, a step of shaking, and a step of ultrasonic treatment, The decolorization method according to claim 6.

8. The decolorization step is performed while supplying the new or recovered and reused first decolorization liquid to the treatment tank and discharging the excess first decolorization liquid from the treatment tank, The decolorization method according to claim 3.

9. The decolorization step includes a step of spraying the first decolorization liquid on the decolorization target as a liquid or a gas at the decolorization temperature, The decolorization method according to claim 1.

10. Further comprising a rinsing step of bringing the decolorization target into contact with a second decolorization liquid for decolorizing the pigment after the decolorization step, The decolorization method according to claim 1.

11. The second decolorization liquid is the same type of liquid as the first decolorization liquid, The decolorization method according to claim 10.

12. Further comprising a liquid removal step of removing the first decolorization liquid from the decolorization target and a drying step of drying the decolorization target, The decolorization method according to any one of claims 1 to 11.

13. The fiber contains at least one of polyester fiber and nylon fiber. The decolorization method according to claim 1.

14. The decolorization temperature is lower than the boiling point of the first decolorizing solution. The decolorization method according to claim 1.

Images