Apparatus and method for removing discoloration or contamination from articles

Abstract

To obtain a method and apparatus that can remove discoloration or contamination from an object while preserving its original color as much as possible, without relying on methods that utilize physical force. [Solution] A method for removing discoloration or contamination from an article, comprising: applying a chemical solution containing an oxidizing agent or a reducing agent to the article; and irradiating the target area of ​​the article with light substantially free of ultraviolet rays from a light source to remove the discoloration or contamination from the article. In some embodiments, the light source is an LED light source, and the illuminance at the target area of ​​the article by the light source is 10,000 lx or more and 500,000 lx or less. In some embodiments, the distance from the light source to the target area of ​​the article is 10 cm or more and 15 cm or less. In some embodiments, discoloration or contamination occurring in at least one of the materials contained in the article, such as fabric, synthetic leather, genuine leather, rubber, resin, wool, and adhesive, is removed.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for removing discoloration or contamination of an article.

Background Art

[0002] Products using synthetic leather or rubber such as shoes may yellow due to aging if they cannot be sold and are stored in a warehouse for a long time. On the other hand, yellowing may also occur when similar products are purchased by an individual as a collection and stored for a long time without being worn.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional cleaning method using physical force, an article may be damaged. Particularly for shoes, although devices for cleaning shoes such as a shoe-only washing machine have been put into practical use in the cleaning industry. However, shoes do not have a washing name like clothing, there is no warning about appearance changes or damage caused by the cleaning device, and no standards have been established in the manufacturing industry either.

[0005] Regarding the problem of yellowing, a method of applying a bleaching agent and irradiating with sunlight or ultraviolet rays to remove yellowing is known. However, some dyes and pigments have weak light resistance, and the color of normal parts without yellowing may fade due to ultraviolet rays. In the conventional method, color bleeding of normal parts may occur during yellowing removal, and the state of the article may be deteriorated by removing yellowing.

[0006] Therefore, there is a need for a method and apparatus that can remove discoloration or contamination from an item while preserving its original color as much as possible, without relying on methods that utilize physical force. [Means for solving the problem]

[0007] One aspect of this technology is a method for removing discoloration or contamination from an article, comprising applying a chemical solution containing an oxidizing agent or a reducing agent to the article, and irradiating the target area of ​​the article with light substantially free of ultraviolet rays from a light source to remove the discoloration or contamination of the article.

[0008] In some embodiments, a light-transmitting chemical solution retaining sheet or a chemical solution retaining sheet that becomes light-transmitting when impregnated with the chemical solution is used. The chemical solution is applied to the article and then impregnated with the chemical solution, or the chemical solution is impregnated with the chemical solution and then applied to the article, thereby adhering the chemical solution to the article. The chemical solution retaining sheet is then covered with a light-transmitting drying protective sheet, and light is shone onto the article from the light source through the drying protective sheet and the chemical solution retaining sheet.

[0009] In some embodiments, the chemical solution is applied to an article by attaching a gel containing the chemical solution to the article, the gel is covered with a light-transmitting drying protective sheet, and light is irradiated onto the article from a light source through the drying protective sheet and the gel.

[0010] In some embodiments, the light source is an LED light source, and the illuminance at the target part of the article due to the light source is 10,000 lx or more and 500,000 lx or less.

[0011] Depending on the embodiment, the distance from the light source to the target part of the article is 10 cm or more and 15 cm or less.

[0012] In some embodiments, the chemical solution holding sheet is made of paper.

[0013] In some embodiments, the chemical solution contains 35% by mass or less of hydrogen peroxide as the oxidizing agent.

[0014] Depending on the embodiment, discoloration or contamination occurring in at least one of the fabrics, synthetic leathers, genuine leathers, rubbers, resins, wools, and adhesives contained in the article is removed.

[0015] Depending on the embodiment, the chemical solution may further include a hydrophilic solvent, a lipophilic solvent, and a surfactant.

[0016] In some embodiments, the pigment extracted into the chemical solution is removed using a wiping material impregnated with 3% to 5% by mass of hydrogen peroxide solution.

[0017] Depending on the embodiment, pigments or dyes adhering to the resin printed portion of the article are removed. [Brief explanation of the drawing]

[0018] [Figure 1] This is a perspective view showing an apparatus for removing discoloration or contamination from an article as one embodiment. [Figure 2] This is a side view of the device in Figure 1 with the right-hand wall removed. [Figure 3] Figure 1 is a perspective view of the device with a stand installed. [Figure 4] Figure 1 is a perspective view of the device with a turntable installed. [Figure 5] Figure 4 is a perspective view showing the turntable with the shoes placed on it. [Figure 6] This is a perspective view of the device shown in Figure 1 with an item placed on it without a stand. [Figure 7] This graph shows the spectral intensity of the irradiated light. [Figure 8] This photograph shows an unexposed shoe with yellowing (left) and a shoe that has been exposed to LED light for 60 minutes (right). The 20 squares indicate the positions of the acquired sample images. [Figure 9] This is a histogram showing the distribution of L* values ​​before and after irradiation in the yellowed area. [Figure 10] It is a histogram showing the distribution of a* values before and after irradiation in the yellowed part. [Figure 11] It is a histogram showing the distribution of b* values before and after irradiation in the yellowed part. [Figure 12] It is a graph showing the spectral intensity distribution of the irradiated light. [Figure 13] It is a photo showing the acquisition locations of sample images in the part where shoe yellowing occurred (only 5 locations are visible for one side). [Figure 14] It is a histogram showing the distribution of L* values before and after irradiation in the yellowed part. [Figure 15] It is a histogram showing the distribution of a* values before and after irradiation in the yellowed part. [Figure 16] It is a histogram showing the distribution of b* values before and after irradiation in the yellowed part. [Figure 17] It is a photo showing the acquisition locations of sample images in the part where no shoe yellowing occurred (3 locations in the rubber part and 2 locations in the sewing part for one side). [Figure 18] It is a graph showing the spectral intensity distribution of the light from the irradiated LED lamp and halogen lamp. [Figure 19] It is a histogram showing the distribution of L* values before and after irradiation of the yellowed part with the LED lamp and halogen lamp. [Figure 20] It is a histogram showing the distribution of a* values before and after irradiation of the yellowed part with the LED lamp and halogen lamp. [Figure 21] It is a histogram showing the distribution of b* values before and after irradiation of the yellowed part with the LED lamp and halogen lamp. [Figure 22] It is a graph showing the time change of L* values when the yellowed part is irradiated with a halogen lamp. The dashed line shows the values when irradiated with an LED lamp without ultraviolet rays for 60 minutes for comparison. [Figure 23] It is a graph showing the time change of a* values when the yellowed part is irradiated with a halogen lamp. [Figure 24]This graph shows the time change in the b* value when a halogen lamp is shone on the yellowed area. [Figure 25] This histogram shows the distribution of L* values ​​before and after irradiation with LED lamps and halogen lamps in the yellowed area. [Figure 26] This histogram shows the distribution of a* values ​​before and after irradiation with LED lamps and halogen lamps in the yellowed area. [Figure 27] This histogram shows the distribution of b* values ​​before and after irradiation with LED lamps and halogen lamps in the yellowed area. [Figure 28] This is a photograph of the "M" shaped resin print on clothing that has been stained with pigment. The squares indicate the locations of the sample images (21 locations in total). [Figure 29] This is a photograph of a garment after the staining has been removed from the resin print portion of the garment, which had been stained with pigment, using one embodiment of the method described. [Figure 30] This is a histogram showing the distribution of L* values ​​before and after LED lamp irradiation in the contaminated area. [Figure 31] This is a histogram showing the distribution of a* values ​​before and after LED lamp irradiation in the contaminated area. [Figure 32] This histogram shows the distribution of b* values ​​before and after LED lamp irradiation in the contaminated area. [Figure 33] This image was created by applying grayscale to a photograph of the contaminated printed area (Figure 27) and then binarizing it at a specific threshold. [Figure 34] This image was obtained by applying grayscale to the photograph of the uncontaminated printed portion (Figure 28), and then binarizing it using the same threshold as in Figure 32. [Modes for carrying out the invention]

[0019] Various embodiments will be described below with reference to the drawings.

[0020] <Methods for removing discoloration or stains from items> First, one aspect of the present invention, a method for removing discoloration or staining from an article, will be described. The type of article to which this method applies is not particularly limited, but it can include clothing such as clothes, socks, gloves, hats, footwear, and accessories, or everyday items such as bags and wallets. From another perspective, it can also apply to articles containing at least one of the following materials that are prone to discoloration or staining: fabric, synthetic leather, genuine leather, rubber, resin, wool, or adhesive. Alternatively, it can apply to the materials themselves or the raw materials of those materials (such as raw wool). Generally, discoloration refers to a change in color caused by a chemical reaction between the materials or adhesives used in an article and external substances such as gases; yellowing is a typical example of discoloration. Staining refers to the adhesion of colored dyes or pigments to the materials (including surface prints and coatings) or adhesives used in an article from an external source.

[0021] This method includes the step of irradiating a target part of an article with light substantially free of ultraviolet rays from a light source through the air. This method removes discoloration or contamination occurring in at least one of the following materials contained in the article: fabric, synthetic leather, genuine leather, rubber, resin (e.g., antioxidants therein), wool, and adhesive. "Substantially free of ultraviolet rays" means that the spectral intensity of ultraviolet light or ultraviolet components contained in the light is less than 2.0% of the peak intensity (in the visible light range). Alternatively, it may mean that the spectral intensity of ultraviolet light is less than 1.7% of the peak intensity in the visible light range.

[0022] [Medication solution application process] This method includes a step of applying a chemical solution to an article (partially to the target area). By applying the chemical solution, the discoloration removal effect by light irradiation, described later, is reinforced, especially for articles that have undergone advanced yellowing. On the other hand, this method does not include a step of simply immersing the article in the chemical solution (solvent, detergent, bleach) or a step of washing by applying any force such as agitation in the chemical solution. As a result, discoloration and stains can be removed while minimizing the impact on the appearance and form of articles for which no washing or cleaning method is specified.

[0023] [Medicinal solution] The chemical solution to be applied may include, for example, a chemical solution containing an oxidizing agent or a chemical solution containing a reducing agent. The chemical solution may be in the form of an aqueous solution. Examples of oxidizing agents include peroxides such as hydrogen peroxide and benzoyl peroxide, addition compounds of peroxides such as sodium percarbonate (sodium carbonate hydrogen peroxide), percarboxylic acids such as peracetic acid and performic acid, and percarbonates such as sodium peroxocarbonate and sodium perborate. The oxidizing agent may be one that is normally used as an oxygen-based bleach. In one embodiment, a chemical solution containing 35% by mass or less of hydrogen peroxide or hydrogen peroxide solution may be used as an oxidizing agent to remove yellowing. Examples of reducing agents include sulfites such as sodium sulfite and sodium bisulfite (sodium bisulfite), thiosulfates such as sodium thiosulfate, boron hydride compounds such as sodium borohydride, dithionite salts such as hydrosulfite (sodium dithionite), and thiourea dioxide. The reducing agent may be one that is normally used as a reducing bleach. In one embodiment, a chemical solution containing oxidizing or reducing agents with a small decolorizing effect, such as hydrogen peroxide, sodium percarbonate, or sodium thiosulfate, can be used. In another embodiment, by selecting an appropriate oxidizing agent, it is possible to remove bacteria, mold, etc. (for example, cleaning bathroom fixtures or parts inside air conditioners) and food waste odors simultaneously with removing discoloration.

[0024] The chemical solution may also be a mixed solution containing at least one non-aqueous solvent along with the oxidizing or reducing agent mentioned above. Mixed solutions containing a non-aqueous solvent are particularly advantageous when it is desired to extract and remove stains caused by pigments or dyes adhering to an article. For example, resin prints on clothing can become stained by the adhesion and penetration of pigments or dyes. However, even when removing discoloration such as yellowing, it is possible that the discoloration is caused by a combination of factors, so in addition to a chemical solution containing an oxidizing agent and a chemical solution containing a reducing agent, a mixed solution further containing a non-aqueous solvent may also be used. The non-aqueous solvent may be a polar or nonpolar solvent. The non-aqueous solvent may be, for example, a water-soluble or hydrophilic solvent. If a non-water-soluble or lipophilic solvent is used as the additional non-aqueous solvent, a surfactant may be further added to the chemical solution. In one particular embodiment, the chemical solution may be a mixed solution containing (1) an oxidizing or reducing agent, (2) a hydrophilic solvent, (3) a lipophilic solvent, and (4) a surfactant. Hereinafter, a mixed chemical solution containing at least this particular combination will be referred to as a "four-component mixed chemical solution". Specifically, hydrophilic solvents can be, for example, alcohols such as methanol, ethanol, isopropyl alcohol, and glycerin; dye carriers included in the formulation of dye carriers such as N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide (DMSO); stain remover components such as γ-butyrolactone and ethylene glycol; or combinations thereof. Lipophilic solvents can be, for example, hydrocarbons such as benzene, cyclohexane, paraffin, toluene, and xylene; esters such as ethyl acetate, butyl acetate, and amyl acetate; ethers such as diethyl ether, tetrahydrofuran (THF), and dioxane; chlorinated solvents such as trichloroethylene and dichloromethane; or combinations thereof. Lipophilic solvents can be volatile. Surfactants are not particularly limited and may be nonionic, ionic (anionic, cationic, or amphoteric) surfactants.In one embodiment, the oxidizing agent or reducing agent may be an alkaline agent or other alkaline oxidizing or reducing agent, such as sodium percarbonate (sodium carbonate hydrogen peroxide), hydrosulfite, or sodium bisulfite (sodium bisulfite).

[0025] Additives such as mold removers, rust removers, chelating agents, alkaline agents, pH adjusters, peroxide reaction accelerators, and peroxide reaction inhibitors can be added to the chemical solution.

[0026] Depending on the type of dye, or under conditions such as when the colored material has been heated after application and firmly fixed to the fabric or print, a four-component chemical mixture containing a reducing agent such as hydrosulfite can be used instead of an oxidizing agent. Furthermore, if metal staining is suspected on the resin part of the item, a reducing agent can be used instead of an oxidizing agent. In addition, a reducing agent can be used for spot-like dye stains.

[0027] [Medication retention sheet] To apply a chemical solution to an article, for example, a light-transmitting chemical solution-holding sheet or a chemical solution-holding sheet that becomes light-transmitting when impregnated with the chemical solution is used. The chemical solution-holding sheet is then placed against the article, and the chemical solution is impregnated into the sheet. In another embodiment, the chemical solution can be applied to the article by impregnating the chemical solution into the chemical solution-holding sheet and then placing the sheet against the article. The chemical solution-holding sheet can be made of a material that becomes light-transmitting when impregnated with the chemical solution. Examples of such materials include tissue paper, thin paper such as calligraphy paper, and gauze. The chemical solution-holding sheet may also be made of a material that is already light-transmitting before being impregnated with the chemical solution.

[0028] In yet another embodiment, the drug solution can be attached to an article by attaching a gel containing the drug solution to the article. The gel is a light-transmitting gel, and can be, for example, a methylcellulose gel.

[0029] This makes it possible to suppress dripping and evaporation of the chemical solution during irradiation, even when removing discoloration from materials that do not easily penetrate the chemical solution, such as synthetic leather. On the other hand, in another embodiment, when removing discoloration from materials that easily penetrate the chemical solution, it is also possible to apply the chemical solution directly to the target area with a brush or similar tool without using a chemical solution retention sheet.

[0030] [Masking tape] For areas where you don't want the chemical solution to come into contact, you can apply masking tape that prevents the solution from penetrating. For areas where you don't want light from a light source to shine, you can apply masking tape that blocks light. This makes it easier to remove localized discoloration and contamination. The ability to use such masking tape makes this method more advantageous than methods that involve applying force to clean the entire item in a washing machine or immersion tank.

[0031] [Dry protection] In the chemical solution application process, to prevent the chemical solution from drying out due to heat from the light source, the chemical solution retention sheet or gel can be covered with a drying protection sheet. If a chemical solution retention sheet or gel is not used, the area to which the chemical solution has been applied can be directly covered with a drying protection sheet. The drying protection sheet should be resistant to moisture evaporation and transmit light, and can be made of cellophane, food wrap, etc. In one embodiment, the chemical solution retention sheet and the protective sheet can be attached to the article in a layered state beforehand.

[0032] [Irradiation process] Next, the target area of ​​the article is irradiated with light substantially free of ultraviolet rays from at least one light source. If a sheet or gel for holding the chemical solution or a sheet for drying protection is used, the light from the light source is irradiated onto the article through the sheet or gel. This removes discoloration or contamination of the article. In addition, because the light from light source 13 does not contain ultraviolet rays, it is possible to prevent the deterioration of light-sensitive dyes or pigments originally contained in the article. In one embodiment, this process can be carried out using the apparatus described in detail later. However, in another embodiment, irradiation can be carried out using other apparatus.

[0033] [light source] The light source 13 can be, for example, an LED lamp (e.g., a white LED lamp) that emits light that does not contain ultraviolet light. The form of the light source 13 can be any shape, such as spherical or planar, and can be, for example, a thin floodlight equipped with an array of many LED elements and a planar diffuser plate, but is not limited to this. The luminous flux emitted by the light source 13 can be between 10,000 lm and 70,000 lm.

[0034] The light source 13 can be positioned above, below, or to the side of an article (front, rear, or side of the device). The distance from the target part of the article to the light source 13 can be within a range of 5 cm or more, 10 cm or more, 15 cm or less, 20 cm or less, 25 cm or less, 30 cm or less, or a combination thereof. If multiple light sources 13 are positioned, the distance from any of the light sources 13 to the target part of the article can be set to fall within one of the above ranges. If the article has multiple target parts, the distance from the light source 13 to all target parts can be set to fall within the above ranges. If the distance to the light source 13 is less than the lower limit of the above range, the light may not reach multiple target parts evenly, and if it exceeds the upper limit of the range, a specific target part may not be sufficiently illuminated.

[0035] The illuminance at the target area of ​​the article by the light source 13 can be within the range of 10,000 lx or more, 50,000 lx or more, 100,000 lx or more, 200,000 lx or less, 500,000 lx or less, or a combination thereof. When a sheet or gel for holding the chemical solution or a sheet for drying protection is used, the illuminance measured on the sheet or gel can be made to fall within the above range. If the illuminance falls below the lower limit of any of the above ranges, the discoloration of the article may not be sufficiently removed, and if it exceeds the upper limit of the range, the energy efficiency may be poor.

[0036] The irradiation time in the irradiation process is not particularly limited, as it depends on the degree of discoloration or contamination. For example, the irradiation time can be 15 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, or 60 minutes or more. There is no upper limit to the irradiation time, and it can usually be until the removal of discoloration or contamination is confirmed.

[0037] [Wipe off the pigment] In one embodiment, the pigment extracted into the chemical solution can be removed using a wiping material during or after light irradiation. The wiping material can be, for example, a cotton swab or a cloth. This process can be repeated until the pigment is completely removed from the article. In one embodiment, the wiping material can be impregnated with hydrogen peroxide. This allows for efficient removal of the pigment. When removing stains caused by dyes or pigments, for example, a four-component chemical solution containing a reducing agent can be applied to the target area, followed by light irradiation, and then wiped with a wiping material impregnated with 3-5% by mass of hydrogen peroxide. Even when removing discoloration such as yellowing, if removal is ineffective, wiping with an oxidizing agent such as hydrogen peroxide can be performed.

[0038] [Post-process] The oxidizing and reducing agents used in the above steps should be neutralized as needed. If an oxidizing agent is used, a reducing agent that has little effect on the dye, such as sodium thiosulfate, can be used. If hydrogen peroxide is used, it should be neutralized using catalase. After neutralization, any remaining chemical solution on the item should be removed while diluting it, for example by dabbing it with a towel soaked in water. Note that during these subsequent steps, the item should not be immersed in water for rinsing or washed by applying force. Any remaining solvent or moisture on the item can be allowed to evaporate naturally or forcibly evaporated and dried using hot air from a hairdryer or similar device.

[0039] <Device for removing discoloration and contamination from items> Next, an apparatus 10 for removing discoloration or contamination from an article, which is another aspect of the present invention, will be described. This apparatus 10 does not include an immersion tank, a washing tank, or a washing tank for simply immersing the article in a chemical solution (solvent, detergent, bleach) or for washing it by applying some force such as stirring in the chemical solution.

[0040] [light source] As shown in Figure 1, the device 10 has at least one light source 13 that emits light that does not contain ultraviolet light. By the light source 13 not emitting ultraviolet light, it is possible to prevent the deterioration of light-sensitive dyes or pigments that were originally contained in the article. The light source 13 can be, for example, an LED lamp (e.g., a white LED lamp) that emits light that does not contain ultraviolet light. The form of the light source 13 can be any shape, such as spherical or planar, and can be, for example, a thin floodlight equipped with an array of many LED elements and a planar diffuser plate, but is not limited thereto. The luminous flux emitted by the light source 13 can be 10,000 lm or more and 70,000 lm or less.

[0041] The light source 13 is positioned so as to emit light toward the article. For example, it can be attached to the ceiling, wall, or bottom of the space containing the article, or to a structure in the same space. Alternatively, as shown in Figure 1, the article can be placed on one of the shelves 15 of the metal wire rack 11, and the light source 13 can be placed face down (for example, upside down) on the shelf 17 above the shelf 15 on which the article is located, so that the light from the light source 13 shines on the article through the wires of the shelf 17.

[0042] The light source 13 can be positioned above, below, or to the side of an article (front, rear, or side of the device). The distance from the target part of the article to the light source 13 can be within a range of 5 cm or more, 10 cm or more, 15 cm or less, 20 cm or less, 25 cm or less, 30 cm or less, or a combination thereof. If multiple light sources 13 are positioned, the distance from any of the light sources 13 to the target part of the article can be set to fall within one of the above ranges. If the article has multiple target parts, the distance from the light source 13 to all target parts can be set to fall within the above ranges. If the distance to the light source 13 is less than the lower limit of the above range, the light may not reach multiple target parts evenly, and if it exceeds the upper limit of the range, a specific target part may not be sufficiently illuminated.

[0043] The illuminance at the target area of ​​the article by the light source 13 can be 10,000 lx or more, 50,000 lx or more, 100,000 lx or more, 200,000 lx or less, or 500,000 lx or less. If the illuminance falls below the lower limit of any of the above ranges, the discoloration of the article may not be sufficiently removed, and if it exceeds the upper limit of the range, the energy efficiency may be poor.

[0044] A shielding plate, such as an acrylic plate or glass plate, that transmits light but prevents the vapor of the chemical solution from passing through can be placed between the light source 13 and the object. This prevents the vapor of the chemical solution generated by heating with light from adhering to the light source 13 and causing a short circuit or other problems.

[0045] [Stand] As shown in Figure 3, in one embodiment, the device 10 can be provided with a stand 20 for placing an object. By placing an object on a stand 20 of an appropriate height, the distance between the light source and the object can be adjusted.

[0046] As shown in Figure 4, in another embodiment, a movable stand such as an electrically rotating turntable 22 can be provided. In this case, as shown in Figure 5, the irradiation process is performed while rotating the turntable 22 on which the article is placed. This reduces the generation of shadows even when the target area is distributed over multiple parts of a three-dimensional article (for example, a shoe 9 as shown in Figure 5). The turntable can be rotated continuously in one direction, for example. However, in another embodiment, the rotation direction of the turntable can be switched alternately in less than one rotation. This switching in less than one rotation makes it possible to avoid interference with the surrounding walls or other articles, for example, even when the storage space is narrow relative to the size of the article or when the distance between it and other articles is small.

[0047] As shown in Figure 6, it is also possible to place items directly on the shelf 15 without using a stand.

[0048] [Reflector] As shown in Figures 1 and 2, the device 10 can be equipped with reflectors that reflect light from the light source 13 toward the items. The reflectors can be, for example, the walls on the sides of the storage space (front, rear, and side of the device 10) which can be made into reflectors 24 or flexible reflective sheets 26. The reflectors 24 and reflective sheets 26 can be, for example, plates with aluminum sheets attached or resin sheets with aluminum vapor deposition (for example, sheets for cold weather protection). The reflective sheet 26 can be, for example, suspended from the top of the wire rack 11 so that the storage space can be opened and closed, and rolled up toward the rear when opened (Figure 2). A reflector 28 can also be placed on the shelf board 15. The reflector 28 on the shelf board 15 can be placed on a riser material 29, for example, an inverted resin tray. This makes it less likely for heat from the light source 13 on the lower shelf to accumulate beneath the reflector 28. As shown in Figure 3, a reflective sheet 30 in a suitable shape, such as a bag, can be placed over the mounting portion of the stand 20. Also, as shown in Figure 4, the upper surface of the turntable 22 can be made into a mirror surface 32. These reflectors eliminate shadows during the irradiation process, even when the target area is dispersed across multiple locations on a three-dimensional object, resulting in more uniform illumination and, consequently, eliminating unevenness and insufficiency in removal.

[0049] [Advantageous effects of the embodiment] Conventional methods, for example, when a peroxide is applied and then exposed to light containing ultraviolet rays such as sunlight, cause the original color of the object to fade due to the interaction between the ultraviolet rays and the peroxide. In contrast, this method, which uses a light source that does not contain ultraviolet rays, makes it possible to powerfully remove discoloration such as yellowing and staining caused by pigments without significantly altering the original color of the object.

[0050] Furthermore, it can remove yellowing and other discoloration from clothing that would normally be washed by soaking in water or hot water, without requiring physical washing. By irradiating without washing, discoloration can be removed from items without causing shape changes that can occur during washing. Also, as shown in Figure 1, if the device is configured using existing racks, a large washing device other than the light source is not required.

[0051] Although various embodiments have been described above, this technology is not limited to the embodiments described above, and those skilled in the art can make various modifications, substitutions, and improvements. [Examples]

[0052] The present invention will be described in more detail below with reference to experimental examples, but the present invention is not limited to the scope of these experimental examples.

[0053] [Experiment 1: Removing yellowing from shoes] For one shoe with yellowing on the white synthetic leather (enamel coating) part of the side, this method was used to irradiate the affected area with LED light from a distance of 15 cm. The irradiation time was 60 minutes. No chemicals such as bleach were used, and no physical cleaning was performed.

[0054] The light irradiated onto the target area was measured using a spectroradiometer (Sekonic Corporation, C-7000) and was as shown in Table 1 and Figure 7 below. [Table 1]

[0055] Table 2 below shows the spectral intensity up to 460 nm, which includes the peak wavelength (455 nm), within the wavelength range of the graph in Figure 7. From this table, it can be seen that the intensity in the ultraviolet region (wavelengths below 400 nm) is less than 1.7% of the peak intensity, indicating that the light from the LED lamp used contained virtually no ultraviolet light. [Table 2]

[0056] Photographs of unirradiated and irradiated shoes were taken with a digital camera (left and right in Figure 8, respectively), and 50x50 pixel square sample images were obtained from the photographs at 20 corresponding locations on each shoe.

[0057] The mean, standard deviation, and coefficient of variation of various color space coordinates were calculated for a total of 50,000 pixels across 20 sample images. The results are shown in Table 3 below. Figures 9 to 11 are histograms showing the frequency (frequency) of pixels with specific L*, a*, and b* values ​​appearing in all sample images. [Table 3]

[0058] The L*a*b* color system represents color using a lightness value L* and two chromaticity values ​​a* and b*, which contain information about hue and saturation (JIS Z 8781-4). Of these, the parameter L*, which represents lightness, takes values ​​from 0 to 100, with larger values ​​indicating whiter (brighter) colors. On the other hand, the two chromaticity values ​​a* and b* take values ​​from 0 in both positive and negative directions, with larger values ​​in the positive direction indicating redder or yellower colors. Conversely, the closer the a* and b* values ​​are to zero, the closer the color is to achromatic.

[0059] From the results in Table 3 and Figures 9-11, the L* value increased slightly after irradiation. The distribution of the a* value shifted from the reddish region to the achromatic region near 0, and the distribution of the b* value shifted from the dark yellowish region to the achromatic region. As a result, the yellowed areas became whiter overall. Therefore, it was confirmed that this method can remove yellowing from shoes.

[0060] [Experiment 2: Confirmation of the effect on areas without yellowing] An experiment was conducted to remove yellowing from a white shoe with yellowing near the sole of the upper using the method described above. First, a turntable 22 was placed on the shelf of the apparatus shown in Figure 1 as a shoe stand. An LED lamp (floodlight) was placed face down on the shelf above as a light source 13 so that the light from the LED lamp shone on the item through the shelf. 3.5% hydrogen peroxide solution was applied to the shoe, and a thin piece of paper that becomes transparent when wet was placed on top to prevent dripping, and then covered with transparent plastic wrap to prevent the chemical solution from drying out. Next, the shoe was placed on the turntable of the apparatus. The area around the storage space was covered with an aluminum sheet (emergency cold-weather sheet) as a reflector to prevent shadows from being cast on the shoe. While the shoe rotated on the turntable, the light from the LED lamp was shone on the target area from a height of 10 cm. No chemicals such as bleach were used, and no physical cleaning was performed.

[0061] The irradiated light, when measured with a spectroradiometer (Sekonic Corporation, C-7000), was as shown in Table 4 and Figure 12 below. [Table 4]

[0062] Table 5 below shows the spectral intensity up to 460 nm, which includes the peak wavelength (446 nm), within the wavelength range of the graph in Figure 12. From this table, it can be seen that the light from the LED lamp used does not contain ultraviolet light (wavelength below 400 nm). [Table 5]

[0063] Sample images were obtained from before-and-after photographs of the upper portion of the shoe near the sole on both sides, where yellowing had occurred. In the photograph in Figure 13, five acquisition locations on one shoe are indicated by squares, but in reality, sample images were obtained from a total of 10 locations on each shoe, including five locations on the opposite side that are not visible in the figure. The color data obtained from the sample images is shown in Table 6 and Figures 14 to 16 below. [Table 6]

[0064] From the results in the table and figure, it can be seen that while the a* value did not change significantly, the b* value (positive values ​​indicate yellowness) approached zero (achromatic) on average, and the distribution became sharper. In addition, the L* value, which had two peaks before irradiation (thought to correspond to areas with and without yellowing), merged into one, and the average value increased. From the above, it can be concluded that the yellowing of the shoes was removed. Visual inspection also clearly confirmed that the yellowing had been removed.

[0065] As shown in the photograph in Figure 17, sample images were also acquired before and after irradiation on the upper surface of the upper part of the shoe, where no yellowing had occurred. Specifically, the acquisition locations were three locations on the rubber part near the toe and two locations on the stitching part near the opening of the shoe on each side. The color data obtained from the sample images is shown in Tables 7 and 8 below. [Table 7] [Table 8]

[0066] The results in the table and figures show that the whiteness (L* value) increased slightly in both the rubber and sewn parts, but there was almost no change in the a* and b* values. Therefore, it was confirmed that the LED lamp irradiation had almost no effect on the color of the parts that had not yellowed.

[0067] [Experiment 3: Confirmation of the effect of ultraviolet light on yellowing removal] An experiment was conducted in which fabric pieces from a child's coat were cut and irradiated for 60 minutes using LED and halogen lamps. The fabric material was polyurethane leather, and the color was a light beige. Multiple fabric samples were subjected to the following treatments: no irradiation, 60 minutes of LED irradiation, and 60 minutes of halogen irradiation. No chemicals were used, and no physical cleaning was performed.

[0068] We used the Shenzhen Hongjin Technology LF150W ultra-thin floodlight as the LED lamp and the Philips ORIGINAL HOME SOLARIA HB406 tanning machine as the halogen lamp. The light actually irradiated onto the target area from these light sources was measured using [device name] and was as shown in Table 9 and Figure 18 below. As can be seen from the spectral intensity in Figure 18, the light emitted by the LED lamp did not contain ultraviolet light (wavelength below 400 nm), while the light emitted by the halogen lamp contained a large amount of ultraviolet light. [Table 9]

[0069] Sample images of 11,660 pixels were obtained from photographs of the fabric before and after illumination with LED lamps and halogen lamps, and the results shown in Table 10 and Figures 19 to 21 below were obtained. [Table 10]

[0070] According to the results in the table and figures, the L* value was significantly higher for both halogen lamps and LED lamps. However, the a* value shifted to the negative side compared to the unirradiated area with halogen lamps, becoming slightly greener, and the distribution became sharper. The b* value approached zero with LED lamps compared to the unirradiated area, and the yellowness decreased, while with halogen lamps, the distribution became more variable and the b* value increased, resulting in a darker yellowness. From the above, it was confirmed that since discoloration can occur in the presence of ultraviolet light, it is advantageous to irradiate with a light source that does not contain ultraviolet light. Furthermore, it was confirmed that this method of irradiating with light that does not contain ultraviolet light is also effective for yellowing of clothing, which is thought to have occurred due to causes different from those of shoe resin and synthetic leather.

[0071] [Experiment 4: Experiment with varying halogen lamp irradiation time] Using the same children's coat fabric as in Experiment 3 described above, we conducted experiments irradiating it with a halogen lamp for 15 minutes, 30 minutes, and 60 minutes. The results are shown in Table 11 and Figures 22-24 below. [Table 11]

[0072] The results in the table and figures show that while 15 minutes of halogen lamp irradiation resulted in incomplete removal of yellowing, after 30 minutes, yellowing caused by ultraviolet light occurred, and after 60 minutes, the yellowing became more pronounced. Although the halogen lamp showed the highest whiteness (L* value) after 15 minutes of irradiation, the a* value was high, leaving a reddish tint that was not completely removed. As a result, it was found that light sources containing ultraviolet light accelerate yellowing, and therefore LED lamps, which do not contain ultraviolet light, are more advantageous for removing yellowing.

[0073] [Experiment 5: Removal of yellowing from clothing using chemical solutions] An experiment was conducted in which a chemical solution containing an oxidizing agent was applied to clothing with yellowing on the collar area, followed by irradiation with an LED lamp. The clothing was placed on a stand 20 as shown in Figure 3, and 3.5 wt% hydrogen peroxide solution (35 wt% hydrogen peroxide solution (manufactured by UBE Hydrogen Peroxide) diluted 10 times) was applied to the yellowed area of ​​the collar. The area was surrounded with a reflector such as an aluminum sheet so that the light would reflect internally, and an LED lamp that does not emit ultraviolet light was shone on the yellowed area of ​​the clothing from a distance of 15 cm. The irradiation time was 60 minutes, and the illuminance was 69700 lx. No physical force was applied during washing.

[0074] Sample images of 50x50 pixels were extracted from photographs of the collar area before and after irradiation, and color data shown in Table 12 and Figures 25-27 below was obtained from them. The results show that the L* value increased, and the distribution of a* and b* values ​​also improved significantly. Therefore, it was found that even when a chemical solution such as hydrogen peroxide is applied and then irradiated with an LED lamp that does not emit ultraviolet light, the effect of removing yellowing by the LED lamp is not lost, but rather enhanced. [Table 12]

[0075] [Experiment 6: Removing print stains from clothing] An experiment was conducted to remove stains from a light green garment that had developed pigment transfer to the white resin print area due to migration sublimation, using the following method combining LED irradiation and a four-component mixed chemical solution. A specific four-component mixed chemical solution was prepared by combining a surfactant (Senkanol GL-100, manufactured by Senka Co., Ltd.), a volatile strong polar organic solvent (Thinner K-3, manufactured by Sanwa Chemical Industry Co., Ltd.), a water-soluble polar solvent (γ-butyllactone (Tokyo Chemical Industries)), and sodium percarbonate paste (Bleach Star, manufactured by Mizuho Chemical Co., Ltd.). This four-component mixed chemical solution was applied to the stained area on the print and covered with cellophane to prevent volatilization. Then, using the apparatus shown in Figure 1, the resin print area was irradiated with light from an LED floodlight at a height of 10-15 cm at an illuminance of 138,000 lx. Every 30 minutes from the start of irradiation, the pigment extracted into the four-component mixed chemical solution was wiped off with a cotton swab soaked in hydrogen peroxide (Oxydol, Ken-ei Pharmaceutical Co., Ltd.). The remaining contaminated areas were again coated with the four-component chemical mixture, and the procedure was repeated to remove the dye. Hydrogen peroxide was neutralized with catalase. The solvent was evaporated with hot air from a hairdryer, and the moisture was allowed to air dry.

[0076] A total of 22,000 pixels of sample images were extracted from photographs of the resin print area before and after irradiation (grayscale images are shown in Figures 28 and 29), and the color data shown in Table 13 and Figures 30 to 32 below was obtained. The results show that after irradiation, the L* value increased and the distribution of the a* value became sharper, and the maximum peak of the b* value shifted from -3 to -2. Therefore, it can be seen that the contamination was removed. The increase in the number of pixels around -2 for the b* value is thought to be due to the removal of contamination from the printed area, which allowed the light green color of the fabric behind the thin print to show through. [Table 13]

[0077] As shown in Figures 33 and 34, the grayscale images before and after irradiation were further binarized using a threshold of 233, the average grayscale value before irradiation (values ​​below the threshold are black). From these binarized images, it can be clearly seen that the mottled horizontal shadows present in the printed area almost completely disappeared after irradiation. From the above, it was confirmed that the present method, which combines irradiation with an LED lamp that does not emit ultraviolet light and the use of a four-component mixed chemical solution, can extract and decompose contaminating pigments that have penetrated deep into the resin of the print without dissolving the original pigments of the print. [Explanation of symbols]

[0078] 10 equipment 11 Wire Rack 13 Light source 15 Shelves for items 17 Shelf for light source 20 Stands 22 Turntables 24 Reflector 26 Reflective sheet 28 Reflector 29. Raising material 30 Reflective Sheets 32 Mirror surface

Claims

1. A method for removing discoloration or contamination from an article, A chemical solution containing an oxidizing agent or a reducing agent is applied to the aforementioned article. A method for removing discoloration or contamination of an article by irradiating a target part of the article with light substantially free of ultraviolet rays from a light source.

2. The method according to claim 1, Using a light-transmitting chemical solution-holding sheet or a chemical solution-holding sheet that becomes light-transmitting when impregnated with the chemical solution, the chemical solution is applied to the article and then impregnated with the chemical solution, or the chemical solution is impregnated with the chemical solution and then applied to the article, thereby causing the chemical solution to adhere to the article. The chemical solution holding sheet is covered with a light-transmitting drying protective sheet. A method of irradiating the article with light from the light source through the drying protective sheet and the chemical solution holding sheet.

3. The method according to claim 1, The liquid medicine is applied to the article by attaching the gel containing the liquid medicine to the article. The gel is covered with a light-transmitting drying protective sheet. A method of irradiating the article with light from the light source through the drying protective sheet and the gel.

4. A method according to claim 1 or 2, wherein the light source is an LED light source, and the illuminance at the target part of the article due to the light source is 10,000 lx or more and 500,000 lx or less.

5. A method according to claim 1 or 2, wherein the distance from the light source to the target part of the article is 10 cm or more and 15 cm or less.

6. The method according to claim 1 or 2, wherein the liquid-holding sheet is made of paper.

7. A method according to claim 1 or 2, wherein the chemical solution contains 35% by mass or less of hydrogen peroxide as the oxidizing agent.

8. A method according to claim 1 or 2, wherein discoloration or staining has occurred on at least one of the fabric, synthetic leather, genuine leather, rubber, resin, wool, and adhesive contained in the article.

9. A method according to claim 1 or 2, wherein the chemical solution further comprises a hydrophilic solvent, a lipophilic solvent, and a surfactant.

10. A method according to claim 9, comprising removing a pigment extracted in the chemical solution with a wiping material impregnated with 3% by mass or more and 5% by mass or less of hydrogen peroxide solution.

11. A method according to claim 9, wherein a pigment or dye adhering to a resin printed portion of the article is removed.

Images