Water scale processing method, coloring agent, and colored base material

Abstract

To provide a new technology for making water scales less visible.SOLUTION: In a processing method of water scale 20, pigments 31 are adhered to water scales 20 occurring in a base material 10 to make the water scales 20 less visible after the pigments 31 are adhered than before the pigment 31 are adhered.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a method for treating limescale, a colorant, and a colored substrate. [Background technology]

[0002] Patent Document 1 discloses a solid scale remover, which is described as being capable of removing scale formed on a substrate simply by rubbing with water. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-44987 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Patent Document 1 removes water stains by polishing, which raises concerns that the surface of the substrate may also be unintentionally scraped. Areas of the substrate surface that have been locally scraped may become shiny, for example. Furthermore, if the surface of the substrate has irregularities, such as anti-slip features, the irregularities may be scraped.

[0005] The present disclosure has been made in consideration of the above-mentioned conventional situation, and aims to provide a new technology for making water stains less noticeable that can solve at least one of the above-mentioned problems. [Means for solving the problem]

[0006] The method for treating water stains disclosed herein applies a pigment to water stains that have formed on a substrate, making the water stains less noticeable after the pigment has been applied than before the pigment has been applied. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. 2 is a diagram schematically illustrating a substrate in an initial state according to the first embodiment. [Figure 2] FIG. 1 is a diagram schematically illustrating a substrate on which water stains have formed. [Figure 3] FIG. 3 is a diagram schematically illustrating how a pigment is attached to the limescale in FIG. 2. [Figure 4] FIG. 1 is a diagram showing a schematic diagram of a colored substrate. [Figure 5] FIG. 10 is a diagram for explaining a method for measuring color difference. [Figure 6] FIG. 2 is a diagram schematically showing the state after polishing. [Figure 7] FIG. 7 is a diagram schematically illustrating how a pigment is attached to the water stains in FIG. 6. [Figure 8] FIG. 1 is a diagram showing a schematic diagram of a colored substrate. [Figure 9] Photographs of each tile in Experiment 2. DETAILED DESCRIPTION OF THE INVENTION

[0008] First, embodiments of the present disclosure will be listed and described. Any combination of the following embodiments without causing any contradiction is also included in the embodiments for carrying out the invention. [1] The method for treating limescale disclosed herein applies a pigment to limescale that has formed on a substrate, making the limescale less noticeable after the pigment has been applied than before the pigment was applied. [2] In the method for treating limescale described in [1] above, the substrate is a water-related component. [3] The colorant of the present disclosure is a colorant used in the method for treating limescale described in either [1] or [2] above, and includes the pigment and one or more binders selected from the group consisting of silica-based binders, zirconia-based binders, alumina-based binders, and titania-based binders. [4] The colored substrate of the present disclosure comprises a substrate and a water stain colored portion in which a pigment has adhered to water stains that have formed on the substrate, and the maximum color difference ΔE measured on the surface is 5.5 or less.

[0009] A first embodiment of the method for treating limescale of the present disclosure will be described with reference to the drawings. In this specification, when a numerical range is described using "greater than or equal to" or "less than or equal to," the range includes both the lower limit and the upper limit unless otherwise specified. For example, the expression "10 or greater and 20 or less" includes both the lower limit of "10" and the upper limit of "20." In this specification, the upper and lower limits of each numerical range can be combined in any combination.

[0010] In the method for treating limescale 20 in embodiment 1, as shown in Figures 1 to 4, a pigment 31 is applied to limescale 20 formed on a substrate 10, and the limescale 20 is made less noticeable after application of the pigment 31 than before application of the pigment 31.

[0011] The substrate 10 is not particularly limited. The substrate 10 may be any of an inorganic substrate, an organic substrate, and an organic-inorganic composite substrate. Examples of inorganic substrates include ceramic substrates, glass substrates, and metal substrates. Specific examples of ceramic substrates include ceramic tiles and sanitary ware. Specific examples of metal substrates include plumbing fixtures. Examples of organic substrates include resin substrates and rubber substrates. Examples of organic-inorganic composite substrates include fiber-reinforced resin substrates. Fiber-reinforced resin is also called FRP. The substrate 10 may or may not have a coating layer on its surface.

[0012] The use of the substrate 10 is not particularly limited. The substrate 10 may be, for example, a wet area component. The wet area component may be, for example, a bathroom component, a toilet component, a washroom component, or a kitchen component. Among these, the substrate 10 is suitable for bathroom floor components, kitchen countertops, and the like, because residual water tends to remain and limescale tends to form.

[0013] The color and surface shape of the substrate 10 are not particularly limited. The substrate 10 may be a dark color such as black, brown, gray, or red. The technology of the present disclosure is particularly effective for a dark-colored substrate 10, in that white water stains 20 are easily noticeable. The surface of the substrate 10 may also be rough with irregularities. If an attempt is made to scrape off the entire water stain 20 of a rough substrate 10 by polishing, the irregularities of the substrate 10 may also be unintentionally scraped off, resulting in concerns about the occurrence of shine and a decrease in anti-slip performance. The technology of the present disclosure is suitable for a rough substrate 10, as it does not require scraping off the entire water stain 20.

[0014] The scale 20 usually occurs when water evaporates from the remaining water on the surface of the substrate 10, leaving inorganic components remaining on the surface of the substrate 10. The scale 20 contains, for example, silica components 21 such as silicic acid, and calcium carbonate components 23 such as calcium carbonate. The scale 20 diffuses light and is visible as a white deposit. The scale 20 formed on the substrate 10 is one factor that makes the substrate 10 look bad.

[0015] The dye 31 selectively absorbs visible light and exhibits a unique color. The dye 31 that can be used is not particularly limited and can be appropriately selected within a range that does not impair the effects of the present disclosure. From the viewpoint of making the water stains 20 less noticeable, the dye 31 is preferably a similar color to that of the substrate 10. Furthermore, the dye 31 is preferably a cationic dye because it is easily fixed to the water stains 20. Examples of cationic dyes include one or more selected from the group consisting of methylene blue, toluidine blue O, fuchsin, crystal violet, rhodamine, auramine, and malachite green.

[0016] The method for treating the limescale 20 can be carried out using a colorant 30 containing the above-described pigment 31 and binder 33. The binder 33 is not particularly limited as long as it contributes to the fixation of the pigment 31. Only one type of binder 33 may be used, or two or more types may be used. The binder 33 is preferably one or more binders selected from the group consisting of silica-based binders, zirconia-based binders, alumina-based binders, and titania-based binders. Among these, silica-based binders are more preferred. Silica-based binders have good affinity with the silica component 21 of the limescale 20 and are suitable for fixing the pigment 31 to the limescale 20. The silica-based binder is, for example, one or more selected from the group consisting of hydrolyzable silane compounds and alkali silicates. Specific examples of hydrolyzable silane compounds include butyl silicate, propyl silicate, ethyl silicate, methyl ethyl silicate, and methyl silicate. An example of butyl silicate is tetrabutoxysilane Si(OC4H9)4. Specific examples of alkali silicates include sodium silicate, lithium silicate, and potassium silicate. Sodium silicate is also called water glass. The silica-based binder can effectively fix the pigment 31 to the limescale 20. The silica-based binder can also fix the pigment 31 to the substrate 10. The silica-based binder can fill in any unevenness between the limescale 20 and the surface of the substrate 10. From the viewpoint of workability, the colorant 30 is preferably a liquid agent, and may contain, for example, either a solvent or a dispersion medium (not shown) together with the pigment 31.

[0017] The following is an example of a method for treating the water stains 20. In one example of the method, first, the substrate 10 on which the water stains 20 have formed is visually observed to identify the area where the water stains 20 have formed. Next, in one example of the method, a colorant 30 is applied to the area where the water stains 20 have formed (see FIG. 3). At this time, it is preferable to also apply the colorant 30 to an area on the surface of the substrate 10 adjacent to the area where the water stains 20 have formed. In one example of the method, the colorant 30 is applied and then allowed to stand. The standing time can be determined through preliminary experiments depending on, for example, the type of colorant 30, the type of substrate 10, the working temperature, etc. The standing time is, for example, from 1 minute to 30 minutes. The standing temperature is, for example, room temperature. Room temperature is typically from 4°C to 40°C. In one example of the method, excess colorant 30 is then washed away.

[0018] When the pigment 31 is applied to the limescale 20, a limescale-colored portion 40 is formed, as shown in FIG. 4 . The manner in which the pigment 31 is applied to the limescale 20 is not particularly limited. For example, the above embodiment may be an embodiment in which the pigment 31 is applied to the limescale 20 via a binder 33 or the like. Because the limescale 20 has the property of adsorbing cationic components, the above embodiment may employ a cationic pigment 31 that is directly applied to the limescale 20. Furthermore, to further reduce the visibility of the limescale-colored portion 40, the above embodiment may be an embodiment in which the pigment 31 is applied to at least a portion of the surface of the substrate 10 together with the limescale 20. The formation of the limescale-colored portion 40 can be confirmed, for example, by observing the limescale 20 at 50x magnification using a microscope. The limescale-colored portion 40 is observed as an image of a whitish limescale 20 to which a pigment 31 of a different color is applied.

[0019] In the method for treating the water stains 20, it can be confirmed, for example, by measuring the color difference that the water stains 20 are less noticeable after the pigment 31 has been applied than before the pigment 31 has been applied. That is, the fact that the water stains 20 are less noticeable can be verified by conducting the following test and confirming that the color difference ΔE2 measured on the substrate 10 after the pigment 31 has been applied is smaller than the color difference ΔE1 measured on the substrate 10 before the pigment 31 has been applied.

[0020] First, the tester observes the surface of the substrate 10 and identifies the scale-adhered region with the largest amount of scale 20 and the scale-free region with the smallest amount of scale based on color, etc. The scale-free region may be a region where the adhesion of scale 20 is not visible. The observation may be visual observation or observation using a microscope.

[0021] The tester measures the L* value (lightness), a* value (chromaticity), and b* value (chromaticity) in the CIE 1976 L*a*b* color system for each of the limescale-covered and limescale-free areas under conditions of a D65 light source and a 10° viewing angle. Measurements can be performed using, for example, a Konica Minolta spectrophotometer, model number CM-700d. Measurements can be performed once or multiple times for each of the limescale-covered and limescale-free areas. If measurements are performed multiple times, the average L* value, average a* value, and average b* value are calculated, and these are defined as the L* value, a* value, and b* value of the area.

[0022] The differences in L*, a*, and b* between the scaled and non-scaled areas are ΔL*, Δa*, and Δb*, respectively. The color difference ΔE is calculated based on the following formula:

[0023] Color difference ΔE=((ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ) 1 / 2

[0024] After the dye 31 is applied to the substrate 10, there may be little difference in color between the scale-covered and non-scale-covered areas, making it difficult to identify the scale-covered and non-scale-covered areas. In such cases, the following supplementary method may be used in combination: The tester identifies a 150 mm × 150 mm area that includes the area with scale 20. The 150 mm × 150 mm area is divided into 100 equal 15 mm × 15 mm areas, and the L*, a*, and b* values are measured for each of these areas. The maximum difference in L*, a*, and b* between any two divided areas is defined as the color difference ΔE between the scale-covered and non-scale-covered areas. If a 150 mm × 150 mm area can be identified within a single substrate 10, a series of areas is identified within the single substrate 10, as shown in Figure 5. 5, the divided area marked "Max" and the divided area marked "min" correspond to a combination of a limescale area and a limescale-free area with the maximum color difference ΔE. If a 150 mm x 150 mm area cannot be identified within a single substrate 10, a 150 mm x 150 mm area can be identified as a total area across multiple substrates 10.

[0025] In this manner, the color differences ΔE1 and ΔE2 of the substrate 10 before and after application of the pigment 31 are calculated. A color difference ΔE2 smaller than the color difference ΔE1 means that the pigment 31 has reduced the color difference between the limescale-covered region and the limescale-free region, making the limescale 20 less visible as a color difference from the substrate 10. In other words, a color difference ΔE2 smaller than the color difference ΔE1 indicates that the limescale 20 is less noticeable after application of the pigment 31 than before application. The difference between the color differences ΔE1 and ΔE2 is preferably 3 or more, more preferably 3.5 or more, even more preferably 4 or more, and may be 7 or more, or 10 or more. The upper limit of the difference between the color differences ΔE1 and ΔE2 is not particularly limited and is, for example, 15 or less.

[0026] In the colored substrate 10, the color difference ΔE2 can be considered the maximum value of the color difference ΔE measured on the surface. The color difference ΔE2 is preferably 5.5 or less, more preferably 4 or less, even more preferably 3.2 or less, even more preferably 1.6 or less, and particularly preferably 1.0 or less. The lower limit of the color difference ΔE2 is not particularly limited, and is usually 0.2 or more. Generally, a color difference of 3.2 or more and 6.5 or less is said to be a range in which the colors can be treated as the same at the impression level. In other words, if the color difference ΔE2 is equal to or less than the above upper limit, the water stain colored portion 40 on the colored substrate 10 will not be noticeable.

[0027] In this method, from the viewpoint of making the water stains 120 even less noticeable, it is preferable to polish the surface of the substrate 110 and the surface of the water stains 120 before adhering the pigment 31. This embodiment will be specifically described with reference to Figs. 6 to 8.

[0028] The method for polishing the surface of the substrate 110 and the surface of the water stains 120 is not particularly limited. Polishing is performed, for example, by rubbing the surface of the substrate 110 and the surface of the water stains 120 with an abrasive material. Examples of the abrasive material include nonwoven fabric, resin sponge, and sandpaper. The polishing time can be set appropriately while observing the polished state of the substrate 110 and the water stains 120. Some of the water stains 120 fall off by polishing. Furthermore, as shown in FIG. 6, fine recesses 111 are formed on the surface of the substrate 110 by polishing. Note that the polishing in this embodiment does not include an embodiment in which substantially all of the water stains 20 are removed by polishing.

[0029] The method for treating the limescale 120 involves polishing, followed by adhering a pigment 31 to the limescale 120 (see FIG. 7). This treatment method allows the pigment 31 to be favorably attached to the substrate 110 by forming minute recesses 111 (see FIG. 8). Such polishing for fixing the pigment 31 is also called "foot-finishing" or the like. This treatment method also makes the limescale 120 and the substrate 110 uniform through polishing. Therefore, the limescale colored portion 140 is less noticeable on the colored substrate 110 compared to when polishing is not performed.

[0030] As described above, the method for treating the water stains 20, 120 involves applying the pigment 31 to the water stains 20, 120 formed on the substrate 10, 110, and making the water stains 20, 120 less noticeable after applying the pigment 31 than before applying the pigment 31. This method for treating the water stains 20, 120 differs from conventional methods for preventing water stains from forming or removing water stains, and can provide a new technology for making the water stains 20, 120 less noticeable.

[0031] The colored substrate 10,110 comprises the substrate 10,110 and a water stain colored portion 40,140 in which a pigment 31 is attached to water stains 20,120 that have formed on the substrate 10,110, and the maximum color difference ΔE measured on the surface is 5.5 or less. Unlike conventional methods for removing water stains, this colored substrate 10,110 can provide a new technology for making the water stains 20,120 less noticeable. [Example]

[0032] The present disclosure will be described in more detail below with reference to examples, although the scope of the present disclosure is not limited to these examples.

[0033] 1. Experiment 1 A black ceramic tile was prepared as the substrate. Approximately 5 mL to 15 mL of water with a total hardness of 97 was sprayed onto the prepared tile, and then it was dried for one hour in a 40°C atmosphere. One spraying and one drying cycle was counted as one cycle, and 20 cycles of spraying and drying were performed to obtain tiles with water stains. On the tiles with water stains, white water stains resembling coffee rings were visible.

[0034] Based on the method described in embodiment 1, the color difference ΔE1 of tiles with limescale before application of the colorant was measured. Specifically, the L*, a*, and b* values were measured at three locations in each of the limescale-covered area and the limescale-free area. The color difference ΔE1 was calculated as the color difference between the average values (N=3) of the L*, a*, and b* values of the limescale-covered area and the average values (N=3) of the L*, a*, and b* values of the limescale-free area. The results are shown in the "Color difference ΔE between A and B" column under "0 minutes" in Table 1.

[0035] A colorant was prepared. The colorant used was a liquid containing a black cationic dye and a binder. The dye was selected from Best Color for Polyester manufactured by Matsuken Co., Ltd. The binder selected was a silica-based binder containing tetrabutoxysilane.

[0036] A coloring agent was applied to each of four black tiles with limescale. Neither the surface of the tiles nor the surface of the limescale was polished before applying the coloring agent. The four tiles with the coloring agent applied were left to stand for 1 minute, 2 minutes, 3 minutes, and 4 minutes, respectively. After that, excess coloring agent was washed off with water and the tiles were dried appropriately. In this way, colored tiles with different coloring times were obtained. When the colored tiles were observed under a microscope (Mx61, manufactured by SKYBASIC) at 50x magnification, limescale-colored areas had formed on the limescale where the pigment had adhered to the limescale on all tiles.

[0037] The color difference ΔE2 of the tiles after application of the colorant was measured in the same manner as the color difference ΔE1, based on the method described in embodiment 1. The results are shown in the "Color difference ΔE between A and B" columns for "1 minute," "2 minutes," "3 minutes," and "4 minutes" in Table 1.

[0038] The appearance of the "0 minute," "1 minute," "2 minute," "3 minute," and "4 minute" tiles was evaluated according to the following criteria. "Especially good" indicates that the water stains were not noticeable and the appearance was particularly good. "Good" indicates that the water stains were not noticeable and the appearance was good. "Poor" indicates that the water stains were noticeable and the appearance was not good. The results are shown in the "Appearance" column in Table 1.

[0039] [Table 1]

[0040] As shown in Table 1, the color difference ΔE1 of the tiles at "0 minutes," i.e., before the colorant was applied, was 13.91. On the other hand, the color difference ΔE2 of the tiles at "1 minute," "2 minutes," "3 minutes," and "4 minutes," i.e., after the colorant was applied, was 3.63-5.45. These results show that by attaching a pigment to the water stains, the water stains can be made less noticeable. Furthermore, by attaching a pigment to the water stains, it was shown that the maximum color difference ΔE measured on the surface of the colored tiles can be reduced to 5.5 or less.

[0041] 2. Experiment 2 Dark gray ceramic tiles, brown ceramic tiles, and black ceramic tiles were prepared as substrates. Photographs of each tile in its initial state are shown in the "Initial state" column of Figure 9.

[0042] Approximately 5 to 15 mL of water with a total hardness of 97 was sprayed onto the prepared tiles, and then they were dried for one hour in an atmosphere at 40°C. One spraying and one drying cycle was counted as one cycle, and 20 cycles of spraying and drying were carried out to obtain tiles with water stains. Photographs of each tile with water stains are shown in the "After Water Staining" column in Figure 9.

[0043] A colorant was prepared. The colorant used was a liquid containing a cationic dye of a similar color to the tile and a binder. The dye was selected from Best Color for Polyester by Matsuken Co., Ltd. The binder selected was a silica-based binder containing tetrabutoxysilane.

[0044] Before applying the colorant, the tile surface and the surface of the limescale were polished using a nonwoven fabric. Photographs of each tile after polishing are shown in the "After Polishing" column of Figure 9. Colorant was applied to each polished tile and allowed to stand for 5 minutes. The excess colorant was washed away with water and allowed to dry appropriately. Photographs of each tile after the first application of colorant are shown in the "After First Coloring" column of Figure 9. The colorant was applied again and allowed to stand for 5 minutes. The excess colorant was washed away with water and allowed to dry appropriately. Photographs of each tile after the second application of colorant are shown in the "After Second Coloring" column of Figure 9. As a result, colored tiles of different colors were obtained. The colored tiles were observed under a microscope (SKYBASIC, Mx61) at 50x magnification, and limescale-colored areas where pigment had adhered to the limescale were found to have formed on all tiles.

[0045] The appearance of the tiles in the "initial state," "after limescale buildup," "after polishing," "after the first coloring," and "after the second coloring" was evaluated according to the following criteria. "Especially good" indicates that the limescale was not noticeable and the appearance was particularly good. "Good" indicates that the limescale was not noticeable and the appearance was good. "Poor" indicates that the limescale was noticeable and the appearance was not good. The results are shown in the "Appearance" column of Figure 9. The evaluation of the appearance "after the second coloring" is also shown in the "Appearance" column of Table 2.

[0046] Based on the method described in embodiment 1, the color difference ΔE2 of the tiles after applying the colorant was measured in the same manner as in experiment 1. The results are shown in the "Color difference ΔE between A and B" columns for "Dark gray," "Brown," and "Black" in Table 2. [Table 2]

[0047] As shown in Table 2, the color difference ΔE2 of the dark gray tile was 0.76. The color difference ΔE2 of the brown tile was 0.94. The color difference ΔE2 of the black tile was 0.75. These results show that by applying a dye to the water stains, the maximum color difference ΔE can be reduced to 5.5 or less, regardless of whether the tile is dark gray, brown, or black. Furthermore, a comparison with the results of Experiment 1 suggests that polishing the surface before applying the dye can make the water stains even less noticeable. It also suggests that applying the dye multiple times, i.e., repeatedly applying the dye, can make the water stains even less noticeable.

[0048] 3. Effects of the Example This example provides a new technique for making water stains less noticeable. [Explanation of symbols]

[0049] 10,110...Base material, 20,120...Scale, 21...Silica component, 23...Chlorine component, 30...Colorant, 31...Pigment, 33...Binder, 40,140...Scale coloring part

Claims

1. The pigment is applied to the water stains on the base material, This method for treating water stains makes the water stains less noticeable after the pigment is attached than before the pigment is attached.

2. The method for treating limescale according to claim 1 , wherein the substrate is a water-related component.

3. A colorant used in the method for treating limescale according to any one of claims 1 and 2, A colorant comprising the pigment and one or more binders selected from the group consisting of silica-based binders, zirconia-based binders, alumina-based binders, and titania-based binders.

4. A substrate; A scale colored portion in which a pigment is attached to the scale generated on the base material, A pigmented substrate having a maximum color difference ΔE measured on the surface of 5.5 or less.

Images