Apparatus and method for removing discoloration of article

Abstract

One embodiment of the present invention is a method for removing discoloration of an article, wherein the discoloration of the article is removed by irradiating, in air, a target site of the article with light that is substantially free of ultraviolet light and that is from a light source. According to the embodiments, the article is irradiated with light without using a chemical solution on the article. According to the embodiments, the light source is an LED light source, and the illuminance at the target site of the article at which the target site is irradiated by the light source is 10000-500,000 lx. According to the embodiments, the distance from the light source to the target site of the article is 10-15 cm According to the embodiments, yellowing occurring in at least one of fabric, synthetic leather, natural leather, rubber, resin, wool, and adhesive included in the article is removed.

Description

Device and Method for Removing Discoloration of an Article

[0001] The technology disclosed in the present application relates to a device and a method for removing discoloration of an article.

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

[0003] In the conventional cleaning method using physical force, the article may be damaged. Especially for shoes, although there are devices for cleaning shoes such as shoe-only washing machines in the cleaning industry that have been put into practical use. However, shoes do not have tags regarding washing method precautions like clothing, there is no warning about appearance changes or damage caused by the cleaning device, and there are no standards established in the manufacturing industry either.

[0004] Regarding the problem of yellowing, there is a known method of applying a bleaching agent and exposing it to sunlight or ultraviolet rays to remove the yellowing. However, some dyes and pigments have weak light resistance, and the color of the normal part without yellowing may fade due to ultraviolet rays. In the conventional method, color bleeding of the normal part may occur during yellowing removal, and the state of the article may be deteriorated by removing the yellowing.

[0005] Therefore, there is a need for a method and a device that can remove discoloration while keeping the original color of the article as much as possible without relying on the method using physical force.

[0006] One aspect of this technology is a method for removing discoloration of an article, which irradiates a target part of the article with light substantially free of ultraviolet rays in the air from a light source to remove the discoloration of the article.

[0007] According to an embodiment, the article is irradiated with light without using a chemical solution on the article.

[0008] According to an embodiment, the light source is an LED light source, and the illuminance at the target part of the article by the light source is 10000 lx or more and 500000 lx or less.

[0009] 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.

[0010] Depending on the embodiment, yellowing that has occurred in at least one of the materials contained in the article—fabric, synthetic leather, genuine leather, rubber, resin, wool, and adhesive—is removed.

[0011] Another aspect of this technology is an apparatus for removing discoloration from an article, comprising: a rotating turntable on which the article is placed; a light source for irradiating the article with light substantially free of ultraviolet rays; and a reflector for reflecting the light from the light source toward the article.

[0012] 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.

[0013] 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.

[0014] Depending on the embodiment, the device may have a housing for the turntable and alternately switch the rotation direction of the turntable in less than one rotation.

[0015] Depending on the embodiment, the reflector may include a mirror surface placed on the upper surface of the turntable and a reflective sheet placed around the turntable.

[0016] This is a perspective view showing an apparatus for removing discoloration from an article as one embodiment. This is a side view of the apparatus in Figure 1 with the right wall removed. This is a perspective view of the apparatus in Figure 1 with a stand installed. This is a perspective view of the apparatus in Figure 1 with a turntable installed. This is a perspective view of the turntable in Figure 4 with a shoe set on it. This is a perspective view of the apparatus in Figure 1 with an article set on it without a stand. This is a graph showing the spectral intensity of the irradiated light. This is a photograph showing an unirradiated shoe with yellowing (left) and a shoe irradiated with LED lamp light for 60 minutes (right). The 20 squares indicate the positions of the acquired sample images. This is a histogram showing the distribution of L* values ​​before and after irradiation in the yellowed area. This is a histogram showing the distribution of a* values ​​before and after irradiation in the yellowed area. This is a histogram showing the distribution of b* values ​​before and after irradiation in the yellowed area. This is a graph showing the spectral intensity distribution of the light from the irradiated LED lamp and halogen lamp. This is a histogram showing the distribution of L* values ​​from the LED lamp and halogen lamp before and after irradiation in the yellowed area. This is a histogram showing the distribution of a* values ​​before and after irradiation with LED lamps and halogen lamps in the yellowed area. This is a histogram showing the distribution of b* values ​​before and after irradiation with LED lamps and halogen lamps in the yellowed area. This is a graph showing the change in L* value over time when the yellowed area is irradiated with a halogen lamp. The dashed line shows the value when the area is irradiated with an LED lamp (without ultraviolet light) for 60 minutes for comparison. This is a graph showing the change in a* value over time when the yellowed area is irradiated with a halogen lamp. This is a graph showing the change in b* value over time when the yellowed area is irradiated with a halogen lamp.

[0017] Various embodiments of this technology will be described below with reference to the drawings.

[0018] <Method for removing discoloration from articles> First, we will explain one aspect of this technology: a method for removing discoloration that has occurred on an article. 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. Alternatively, it can also apply to articles containing materials that are prone to discoloration, such as fabrics, synthetic leather, genuine leather, rubber, resin, and wool, or at least one 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. Contamination refers to the adhesion of colored dyes, pigments, and other colored substances from the outside to the materials (including surface prints and coatings) or adhesives used in an article.

[0019] This method includes a 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 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. On the other hand, this method does not include a step of applying a chemical solution (solvent, detergent, bleach) to the article, a step of immersing it in a chemical solution, or a step of washing it by applying any force such as agitation in a chemical solution. This makes it possible to remove discoloration while minimizing the impact on the appearance and form of articles for which no washing or cleaning method is specified. Note that "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.

[0020] [Irradiation Process] Without using any chemicals on the article, light substantially free of ultraviolet rays is irradiated onto the target area of ​​the article from at least one light source. This removes discoloration of the article. Furthermore, because the light from light source 13 does not contain ultraviolet rays, it is possible to prevent the deterioration of lightfast dyes or pigments that were 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.

[0021] [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 thereto. The luminous flux emitted by the light source 13 can be 10,000 lm or more and 70,000 lm or less.

[0022] 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 an article has multiple target parts, the distance to the light source 13 for 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.

[0023] 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. 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, energy efficiency may decrease.

[0024] The irradiation time in the irradiation process is not particularly limited, as it depends on the degree of discoloration. 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 is confirmed.

[0025] <Apparatus for removing discoloration from articles> Next, an apparatus for removing discoloration that has occurred on articles, which is another aspect of this technology, will be described. Apparatus 10 as one embodiment does not include an immersion tank, washing tank, or washing tank for simply immersing articles in a chemical solution (solvent, detergent, bleach) or for washing them by applying some force such as stirring in the chemical solution.

[0026] [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 and 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.

[0027] 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.

[0028] 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 an article has multiple target parts, the distance to the light source 13 for 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.

[0029] 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.

[0030] [Stand] As shown in Figure 3, in one embodiment, the device 10 can be provided with a stand 20 for placing an object on. By placing an object on a stand 20 of an appropriate height, the distance between the light source and the object can be adjusted.

[0031] 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.

[0032] As shown in Figure 6, it is also possible to place items directly on the shelf 15 without using a stand.

[0033] [Reflector] As shown in Figures 1 and 2, the device 10 can be provided with a reflector that reflects light from the light source 13 toward the items. The reflector can be, for example, a reflector 24 or a flexible reflective sheet 26 on the side walls of the storage space (front, rear, and side of the device 10). The reflector 24 or reflective sheet 26 can be, for example, a board with an aluminum sheet attached or a resin sheet with aluminum vapor deposition (for example, a cold-weather sheet). 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, for example, placed on top of a riser material 29 such as an inverted resin tray. This makes it possible to prevent heat from the light source 13 on the lower shelf from accumulating 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.

[0034] [Advantageous Effects of the Embodiment] In conventional methods, for example, when a peroxide is applied and then irradiated with light containing ultraviolet rays, such as sunlight, the original color of the article is lost due to the interaction between 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 without significantly altering the original color of the article.

[0035] 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.

[0036] This method does not use chemicals such as bleach, which has the advantage of not damaging items with chemicals, and also improves work efficiency because there is no need for chemical neutralization cleaning.

[0037] 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 to these embodiments.

[0038] The present invention will be explained in more detail below with reference to experimental examples, but the present invention is not limited to the scope of these experimental examples.

[0039] [Experiment 1: Removal of yellowing from shoes] One shoe with yellowing on the white synthetic leather (enamel coating) part of the side was treated with this method, and the area was illuminated 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.

[0040] The light emitted from the target area of ​​the shoe was measured using a spectroradiometer (Sekonic Corporation, C-7000) and was as shown in Table 1 and Figure 7 below.

[0041] 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.

[0042] 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.

[0043] 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 (number of times) that pixels with specific L*, a*, and b* values ​​appear in all sample images.

[0044] The L*a*b* color space represents color with a lightness value L* and two chromaticity values a* and b* that carry hue and chroma information (JIS Z 8781-4). Among these, the parameter L* representing lightness takes values from 0 to 100, and the larger the value, the whiter (brighter) it is. On the other hand, the two chromaticity values a* and b* take values in both positive and negative directions from 0, and the larger they are in the positive direction, the more they exhibit a reddish and yellowish tint. Conversely, the closer both the a* value and the b* value are to zero, the closer they are to achromatic colors.

[0045] From the results in Table 3 and Figures 9 to 11, after irradiation, the L* value increased slightly. 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 region with a strong yellow tint to the achromatic region. As a result, it can be said that the yellowed part became white overall. Therefore, it was confirmed that the yellowing of shoes can be removed by this method.

[0046] [Experiment 2: Confirmation of the influence on the yellowing removal effect of ultraviolet rays] A plurality of sample pieces were cut from the fabric of a children's coat, and an experiment was conducted in which some of them were irradiated with an LED lamp or a halogen lamp for 60 minutes. The fabric material was polyurethane leather, and the color was beige close to white. A plurality of cut sample fabric pieces were subjected to non-irradiation, 60-minute irradiation with an LED lamp, and 60-minute irradiation with a halogen lamp. No chemicals were used, and no physical force was applied for washing.

[0047] As the LED lamp, the ultra-thin projector LED Flood light LF150W manufactured by Shenzhen Hongjin Technology was used, and as the halogen lamp, the tanning machine ORIGINAL HOME SOLARIA HB406 manufactured by PHILIPS was used. When measuring the light actually irradiated onto the target part of the sample fabric pieces from these light sources, it was as shown in Table4 and Figure 12 below. As can be seen from the spectral intensity in Figure 12, the light emitted by the LED lamp did not contain ultraviolet rays (wavelength 400 nm or less), while the light emitted by the halogen lamp contained a lot of ultraviolet rays.

[0048] Sample images of 11,660 pixels were obtained from photographs of fabric pieces before and after irradiation with LED lamps and halogen lamps, and the results shown in Table 5 and Figures 13 to 15 below were obtained.

[0049] 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.

[0050] [Experiment 3: Experiment with varying halogen lamp irradiation time] Using the same children's coat fabric pieces as in Experiment 2, an experiment was conducted in which halogen lamp irradiation time was varied to 15 minutes, 30 minutes, and 60 minutes. The results are shown in Table 6 and Figures 16-18 below.

[0051] 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.

Claims

1. A method for removing discoloration from an article, comprising irradiating a target part of the article with light substantially free of ultraviolet rays from a light source into the air to remove the discoloration of the article.

2. The method according to claim 1, wherein light is irradiated onto the article without using a chemical solution on the article.

3. The 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.

4. A method according to any one of claims 1 to 3, wherein the distance from the light source to the target part of the article is 10 cm or more and 15 cm or less.

5. A method according to any one of claims 1 to 3, wherein yellowing has occurred in at least one of the fabric, synthetic leather, genuine leather, rubber, resin, wool, and adhesive contained in the article.

6. An apparatus for removing discoloration from an article, comprising: a rotating turntable on which the article is placed; a light source for irradiating the article with light substantially free of ultraviolet rays; and a reflector for reflecting the light from the light source toward the article.

7. The apparatus according to claim 6, 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.

8. The apparatus according to claim 6 or 7, wherein the distance from the light source to the target part of the article is 10 cm or more and 15 cm or less.

9. An apparatus according to any one of claims 6 to 8, comprising a housing for housing the turntable, and for alternately switching the rotation direction of the turntable in less than one rotation.

10. An apparatus according to any one of claims 6 to 9, wherein the reflector comprises a mirror surface disposed on the upper surface of the turntable and a reflective sheet disposed around the turntable.

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