JP6774270B2 - Water discoloration indicator - Google Patents

Description

The present invention relates to a water discoloration indicator. More specifically, the present invention relates to a water discoloration indicator that can visually recognize a different aspect from the dry state due to the adhesion of water.

Conventionally, a discolorable laminate in which a porous layer containing a low refractive index pigment is formed on the surface of a support, water is absorbed by the porous layer to make it transparent, and the color of the base is revealed has been disclosed. (See, for example, Patent Document 1).
Further, a discolorable adhesive label in which an adhesive layer is provided on the back surface of a transparent substrate and a porous layer containing a low refractive index pigment and a colored layer are provided on the surface of the transparent substrate is disclosed (for example, a patent). Reference 2).
Although the discolorable laminate and the discolorable adhesive label can be used as an indicator for detecting the adhesion of water, it can only confirm the state in which water is attached, and it returns to the original state by drying. It was not possible to determine if there was any adhesion.
Further, as another attempt, a water-wetting-sensing printed matter in which an ink containing a water-soluble dye is printed on a paper that does not easily repel water is disclosed (see, for example, Patent Document 3).
In the water-wetting-sensing printed matter, the water-soluble dye elutes from the printed portion and exudes to the non-printed portion due to the adhesion of water, so that it is possible to determine whether or not water has adhered in the past. It did not have a function to determine whether or not the dye was attached.

Japanese Unexamined Patent Publication No. 11-1982271 JP-A-2007-322594 Japanese Unexamined Patent Publication No. 10-2893

It is an object of the present invention to provide a water discoloration indicator having a function of determining whether or not water has adhered in the past and at present whether or not water has adhered.

In the present invention, a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state on a support, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state, and on the porous layer. the coloring layer to solubilize with water provided partially Ri name colored layer to solubilize in the water, a layer containing a water-soluble dye and a binder resin, said binder resin is a water-soluble resin and a water-insoluble A water discoloration indicator containing a resin , or a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state on a support, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state. , A water discoloration indicator in which colored layers that are solubilized with water are arranged side by side, or a colored layer that is solubilized with water on a support and a low refractive index pigment dispersed on the colored layer in a binder resin. was fixed to be opaque in a non-liquid absorbing state, Ri Na provided a porous layer of clearing in liquid absorption state, the colored layer is solubilized with the water, a layer containing a water-soluble dye and a binder resin Yes, the binder resin requires a water discoloration indicator containing a water -soluble resin and a water -insoluble resin .
Further, on the support, a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state, and a coloring solubilized in water. In the water discoloration indicator formed by arranging the layers side by side, the colored layer solubilized with water is a layer containing a water-soluble dye, and the colored layer solubilized with water contains a water-soluble dye and a binder resin. It is a requirement that the binder resin contains a water-soluble resin and a water-insoluble resin .
Further , the support is a water-permeable support, a waterproof layer is provided on the uppermost layer, a non-discoloring colored layer is provided on the support, and an adhesive layer is provided on the lowermost layer. It is a requirement that it be provided.

The present invention can provide a highly convenient water discoloration indicator having a function of determining whether or not water has adhered in the past and at present whether or not water has adhered.

It is a vertical sectional view of one reference example of the water discoloration indicator of this invention. It is a vertical sectional view of one Example of the water discoloration indicator of this invention. It is a vertical sectional view of another reference example of the water discoloration indicator of this invention. It is a vertical sectional view of another reference example of the water discoloration indicator of this invention.

In the present invention, a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state on a support, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state, and on the porous layer. It is opaque in a non-liquid absorbing state in which a low refractive index pigment is fixed to a binder resin in a dispersed state on a water discoloration indicator or a support partially provided with a colored layer that is solubilized with water. An opacity indicator formed by arranging a porous layer that becomes transparent in a liquid absorbing state and a colored layer that is solubilized with water, or a colored layer that is solubilized with water and the colored layer on a support. It is a water discoloration indicator in which a low refractive index pigment is fixed to a binder resin in a dispersed state, and a porous layer that is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state is provided.
Among them, a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state on a support, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state, and water on the porous layer. The water discoloration indicator, which is partially provided with a colored layer solubilized in, will be described.

The support is not particularly limited, and for example, cloth such as paper, synthetic paper, woven fabric, knitted fabric, braid, non-woven fabric, natural or synthetic leather, plastic, glass, ceramics, metal, wood, stone and the like are used. Cloth, synthetic paper, and plastic are preferably used. Further, the shape may be a planar shape or a three-dimensional shape.
The support itself may be colored, or may have a non-discoloring colored layer provided on the support.
Examples of the coloring agent for coloring the support or the coloring agent contained in the non-discoloring coloring layer include general dyes, fluorescent dyes, and coloring pigments, and among them, the coloring pigments include general pigments and fluorescent pigments. In addition to metal powder, a transparent metallic bright pigment (pearl pigment) in which a core material such as mica, alumina, or glass is coated with titanium oxide can be exemplified.

The porous layer is a layer in which a low refractive index pigment is fixed together with a binder resin in a dispersed state, and has different transparency in a dry state and a liquid absorbing state.
The refractive index of the low refractive index pigment is in the range of 1.4 to 1.8, and exhibits good transparency when it absorbs water.
Examples of the low refractive index pigment include silicic acid and salts thereof, barite powder, barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, talc, alumina, alumina white, magnesium carbonate and the like, and silicic acid and salts thereof are preferable. Used.
Examples of the salt of silicic acid include aluminum silicate, potassium aluminum silicate, sodium aluminum silicate, aluminum calcium silicate, potassium silicate, calcium silicate, sodium calcium silicate, sodium silicate, magnesium silicate, potassium magnesium silicate and the like.
Further, two or more kinds of the low refractive index pigments can be used in combination.
The particle size of the low refractive index pigment is not particularly limited, but those having a diameter of 0.03 to 10.0 μm are preferably used.
Silicic acid is mentioned as a preferably used low refractive index pigment.
The silicic acid may be a silicic acid produced by a dry method, but a silicic acid produced by a wet method (hereinafter referred to as a wet method silicic acid) is particularly effective. Explaining this point, the silicic acid is amorphous. It is produced as a quality amorphous silicic acid, and depending on the production method, a dry method using a vapor phase reaction such as thermal decomposition of silicon halide such as silicon tetrachloride (hereinafter referred to as dry silicic acid) and sodium silicate It is roughly divided into the wet method using a liquid phase reaction such as decomposition with an acid such as, and the structure is different between the dry method silicic acid and the wet method silicic acid, and the dry method silicic acid has a three-dimensional structure in which silicic acid is tightly bonded. On the other hand, the wet method silicic acid has a so-called two-dimensional structural portion in which silicic acid is condensed to form a long molecular arrangement.
Therefore, since the molecular structure is coarser than that of the dry silicic acid, when the wet silicic acid is applied to the porous layer, the diffuse reflection of light in the dry state is excellent as compared with the system using the dry silicic acid. Therefore, it is presumed that the concealment property under normal conditions will increase.
Further, since the porous layer absorbs water, the wet silicic acid has more hydroxyl groups existing as silanol groups on the particle surface than the dry silicic acid, and has a high degree of hydrophilicity. It is preferably used.
In addition, in order to adjust the hiding property of the porous layer in a normal state and the transparency in a liquid absorbing state, another general-purpose low refractive index pigment can be used in combination with the wet method silicic acid.

The low refractive index pigment in the porous layer depends on properties such as particle size, specific surface area, and oil absorption, but in order to satisfy both the hiding property in the normal state and the transparency in the liquid absorbing state, it is necessary. preferably the coating amount is 1 to 30 g / ^{m 2,} more preferably 5 to 20 g / ^{m 2.} If it is less than 1 g / m ² , it is difficult to obtain sufficient hiding property under normal conditions, and if it exceeds 30 g / m ² , it is difficult to obtain sufficient transparency at the time of liquid absorption.
The low refractive index pigment is dispersed in a vehicle containing a binder resin as a binder, applied to a support, and then dried to form a porous layer.
Examples of the binder resin include urethane resin, nylon resin, vinyl acetate resin, acrylic acid ester resin, acrylic acid ester copolymer resin, acrylic polyol resin, vinyl chloride-vinyl acetate copolymer resin, maleic acid resin, polyester resin, and styrene. Resin, styrene copolymer resin, polyethylene resin, polycarbonate resin, epoxy resin, styrene-butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, methyl methacrylate-butadiene copolymer resin, butadiene resin, chloroprene resin, melamine resin, and the above. Examples thereof include each resin emulsion, casein, starch, cellulose derivative, polyvinyl alcohol, urea resin, phenol resin and the like.
The mixing ratio of the low refractive index pigment and these binder resins depends on the type and properties of the low refractive index pigment, but preferably, the binder resin solid content is 0.5 to 1 part by mass of the low refractive index pigment. It is 2 parts by mass, more preferably 0.8 to 1.5 parts by mass. When the binder resin solid content is less than 0.5 parts by mass with respect to 1 part by mass of the low refractive index pigment, it is difficult to obtain a practical film strength of the porous image, and when it exceeds 2 parts by mass. In addition, the permeability of water into the porous layer is deteriorated.
Since the mixing ratio of the binder resin to the colorant is smaller in the porous layer than in a general coating film, it is difficult to obtain sufficient film strength. Therefore, it is effective to use a nylon resin or a urethane-based resin among the above-mentioned binder resins in order to increase the scratch resistance.
Examples of the urethane-based resin include polyester-based urethane resin, polycarbonate-based urethane resin, and polyether-based urethane resin, and two or more of them can be used in combination. Further, a colloid in which the resin is emulsified and dispersed in water or self-emulsified by the ionic group of the ionic urethane resin (urethane ionomer) itself without the need for an emulsifier and dissolved or dispersed in water. A dispersed type (ionomer type) urethane resin can also be used.
Either an aqueous urethane resin or an oily urethane resin can be used as the urethane resin, but in the present invention, an aqueous urethane resin, particularly a urethane emulsion resin or a colloidal dispersion type urethane resin is preferable. Used for.
The urethane-based resin can be used alone, but other binder resins can also be used in combination depending on the type of support and the performance required for the film. When a binder resin other than the urethane resin is used in combination, it is preferable that the urethane resin is contained in the binder resin of the porous layer in a solid content mass ratio of 30% or more in order to obtain a practical film strength.
Among the binder resins, those having a crosslinkable property can be further improved in film strength by adding an arbitrary cross-linking agent and cross-linking.
The binder resin has different affinities with water, and by combining these, the permeation time into the porous layer, the degree of permeation, and the slow speed of drying after permeation can be adjusted. Further, the adjustment can be controlled by appropriately adding a dispersant or a surfactant.

The porous layer can be coated by screen printing, offset printing, gravure printing, coater, tampo printing, transfer or other printing means, brush coating, spray coating, electrostatic coating, electrodeposition coating, sink coating, roller coating, dip coating, etc. It can be formed on a support.
The porous layer may be an image of a circle, an ellipse, a square, a rectangle, or the like, but in addition to various characters, symbols, figures, and patterns, people, animals, plants, fruits, foodstuffs, vehicles, and buildings. , An image of a celestial body or the like.

Examples of the water-soluble colored layer provided on the porous layer include a colored layer composed of a water-soluble dye and, if necessary, a binder resin, or a colored layer containing a pigment and a water-soluble resin.
In the colored layer, the water-soluble dye contained in the colored layer elutes to the surroundings due to the adhesion of water, and the pigment diffuses to the surroundings, so that it is possible to determine whether or not water has adhered in the past.
As the water-soluble dye, acid dyes, basic dyes, direct dyes and the like can be used.
Acid dyes include ponceau (CI 16255), tartrazine (CI 19140), acid blue black 10B (CI 20470), guinea green (CI 42085), brilliant blue FCF. (CI 42090), Acid Violet 6B (CI 42640), Solve Blue (CI 42755), Naphthalene Green (CI 44025), Eosin (CI 45380), Phloxine (CI 45410), erythrosine (CI 45430), niglosin (CI 50420), acid phloxine (CI 56205) and the like are used.
As basic dyes, chrysoidin (CI 11270), methyl violet FN (CI 42535), crystal violet (CI 42555), malachite green (CI 42000), Victoria blue FB ( CI 44045), Rhodamine B (CI 45170), Acridine Orange NS (CI 46005), Methylene Blue B (CI 52015) and the like are used.
As direct dyes, Congo Red (CI 22120), Direct Sky Blue 5B (CI 24400), Violet BB (CI 27905), Direct Deep Black EX (CI 30235), Kaya Lath Black G Conc (CI 35225), Direct Fast Black G (CI 35255), Phthalocyanine Blue (CI 74180) and the like are used.
Examples of the pigment include inorganic pigments such as carbon black and ultramarine, organic pigments such as copper phthalocyanine blue and benzidine yellow, synthetic resin fine particle fluorescent pigments in which various fluorescent dyes are solid-solved in a resin matrix, and metallic gloss pigments. It can be exemplified.

As the binder resin, either a water-soluble resin or a water-insoluble resin can be used, but a water-soluble resin is preferably used, and a water-soluble resin and a water-insoluble resin are more preferably used in combination.
By using the water-soluble resin, the elution property and diffusibility at the time of water adhesion are excellent, and by using the water-soluble resin and the water-insoluble resin in combination, the elution property and diffusibility at the time of water adhesion are excellent and high. It also has excellent storage stability in the initial state of the colored layer under humidity.
When the water-soluble resin and the water-insoluble resin are used in combination, it is preferable to use the water-soluble resin and the water-insoluble resin in the colored layer in a mass ratio of 95: 5 to 5:95, more preferably 90. : 10 to 10:90.
The water-soluble resin is not particularly limited as long as it is soluble in water, but is a water-soluble synthesis of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, polyethylene glycol, water-soluble acrylic resin, water-soluble nylon resin and the like. Resin, sodium alginate, propylene glycol alginate, gum arabic, casein, sodium caseinate, guar gum, gelatin, dextrin, starch, processed starch, water-soluble resin derived from natural products such as reduced candy, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose , Methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl ethyl cellulose, and other cell rolls and cellulose derivatives and salts thereof, and polysaccharides such as dextran, starch sugar, pullulan, and cycloamylose.
Examples of the water-insoluble resin include urethane-based resin, nylon resin, vinyl acetate resin, acrylic acid ester resin, acrylic acid ester copolymer resin, acrylic polyol resin, vinyl chloride-vinyl acetate copolymer resin, maleic acid resin, and polyester resin. , Styrene resin, styrene copolymer resin, polyethylene resin, polycarbonate resin, epoxy resin, styrene-butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, methyl methacrylate-butadiene copolymer resin, butadiene resin, chloroprene resin, melamine resin, And emulsions of the above-mentioned resins and the like.

The colored layer is formed by mixing a colorant such as a water-soluble dye or a pigment in a vehicle to prepare a liquid composition such as a paint or a printing ink, and by the same means as the porous layer.
As the solvent for the paint or printing ink, water, water and a water-soluble organic solvent, or a solvent can be used.
The solvents are aromatic hydrocarbons of benzene, toluene and xylene, hexane, cyclohexane, saturated hydrocarbons of octane, acetone, methyl ethyl ketone, ketones of cyclohexanone, chloroform, halogenated hydrocarbons of trichloroethane, mineral spirit and petroleum ether. Petroleum solvent can be mentioned.
The paint or printing ink may contain a thickener, a dispersant, a pH adjuster, a preservative, an antifungal agent, an antioxidant, or the like, if necessary.

The colored layer is partially provided on the porous layer, and includes various characters, symbols, figures, patterns, and shapes such as people, animals, plants, fruits, foodstuffs, vehicles, buildings, and celestial bodies. The pattern may be an independent discontinuous pattern such as a polka dot pattern, or may be a partially connected continuous pattern such as a lattice pattern.
The area ratio of the portion of the porous layer on which the colored layer is formed and the portion where the colored layer is not formed is not particularly limited, but is 0.1: 99.9 to 30:70 per 1 cm ² . When the ratio is preferably 1:99 to 20:80, it is appropriately provided over the entire surface of the porous layer to enhance the texture of the water discoloration indicator in the dry state, and the colored layer in the liquid absorbing state. You can see a clear image of.

The colored layer is partially provided on the porous layer, and it is possible to determine whether or not the colorant is eluted or diffused into the porous layer due to the adhesion of water and the water is attached. ..
As the colored layer, the colored layer containing the water-soluble dye is preferably used because the water-soluble dye is easily eluted into the porous layer due to the adhesion of water and is highly variable.

Next, on the support, a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state, and a colored layer which is solubilized in water. The water discoloration indicator, which is arranged side by side, will be described.
The material and shape of the support are the same as described above, and the support itself may be colored, or a non-discolorable colored layer may be provided on the support.
The porous layer and the colored layer solubilized with water are the same as described above, and the porous layer and the colored layer are arranged side by side on the support.
Therefore, when water adheres, the water-soluble dye contained in the colored layer elutes to the surroundings, and the pigment diffuses to the surroundings, so that it is possible to determine whether or not water has adhered in the past.
The porous layer and the colored layer do not have to be in contact with each other, but when they are arranged in close contact with each other, the water-soluble dye or the diffused pigment in which the colored layer is eluted adheres to the porous layer, so that the color is blurred. Excellent storage stability of the layer.
The porous layer becomes transparent by absorbing water so that the color of the base can be visually recognized, and returns to the original state by drying. Therefore, it is possible to determine whether or not water is attached at the present time.

Next, a colored layer that is solubilized with water and a low refractive index pigment are fixed to the binder resin in a dispersed state on the support, which is opaque in a non-liquid absorbing state and transparent in a liquid absorbing state. A water discoloration indicator provided with a porous layer to be transformed will be described.
The material and shape of the support are the same as described above, and the support itself may be colored, or a non-discolorable colored layer may be provided on the support.
The porous layer and the colored layer solubilized with water are the same as described above, and the colored layer is provided on the support and the porous layer is provided on the colored layer.
Therefore, when water adheres, the water-soluble dye contained in the colored layer elutes into the upper porous layer, or the pigment diffuses into the upper porous layer, and the color of the colored layer can be visually recognized from the surface of the porous layer. Therefore, it is possible to determine whether or not water has adhered in the past.
The porous layer becomes transparent by absorbing water so that the color of the base can be visually recognized, and returns to the original state by drying. Therefore, it is possible to determine whether or not water is attached at the present time.

The water discoloration indicator is formed of a water-permeable support, for example, a material such as a cloth or a film having through holes, paper, synthetic paper, etc., so that not only water adhering from the front surface but also water adhering from the back surface is attached. It can also detect water.
In a system using a water-permeable support, by providing a waterproof layer on the uppermost layer, an indicator for detecting water adhering from the back surface can be obtained.
The waterproof layer is a transparent layer, and is a polyethylene, polystyrene, polypropylene, polyvinyl chloride, polyvinyl chloride, cellophane film, silicone resin, polyamide resin, cellulose resin, acrylic resin, epoxy resin. , It is preferable that the varnish is made of at least one selected from synthetic rubber varnishes.

The water discoloration indicator can be easily adhered to an object by providing an adhesive layer at the bottom layer.
The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive mainly composed of a general-purpose acrylic resin, urethane-based resin, styrene-butadiene copolymer, vinyl ether copolymer, natural rubber, or the like.
In addition, a release layer such as a release paper may be provided on the adhesive layer for convenience during use.

The water discoloration indicator can be attached to an article, cut into a desired size and shape and attached to the article, or a water discoloration indicator can be wound on the surface of a winding core formed of paper or the like. It can also be put into practical use as a tape form.
By adopting the tape form, it is easy to carry and it is not necessary to provide a release layer, so that resource saving can be promoted, and it can be cut into an appropriate size according to the length of the object and attached. Satisfies applicability to articles of various shapes and sizes.

Examples of the object to which the water discoloration indicator is attached include water leakage detection of pipes, pipes, water tanks, etc., and disposable diapers, which can detect urine.

Examples of the present invention will be described below. In addition, the part in an Example shows a mass part.
Reference example 1 (see Fig. 1)
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP-10, Dainippon Ink Chemicals] on the surface of blue polyethylene terephthalate film as support 2. Made by Kogyo Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoamer 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate-based cross-linking agent 3 parts mixed The entire surface was solid-printed on a 100-mesh screen plate using the screen printing ink, and dried and cured at 60 ° C. for 30 minutes to form the porous layer 3.
Next, 1.0 part of phloxine (CI 45410), 50.0 parts of polyvinylpyrrolidone resin (trade name: Socalan K-17, manufactured by BASF), and 50.0 parts of water were placed on the porous layer as a red water-soluble dye. A dot pattern having a diameter of 2 mm is printed on a 180-mesh screen plate using a screen printing ink containing a portion, and dried and cured at 50 ° C. for 30 minutes to form a colored layer 4 to obtain a water discoloration indicator 1. It was.

When the back surface (support side) of the water discoloration indicator was attached to the pipe and put into practical use, a white dot pattern due to the porous layer and a red dot pattern due to the colored layer were visually recognized in the normal state (non-water absorption state). When water adheres from the indicator surface, the water-soluble dye contained in the colored layer elutes to the surroundings and the dot pattern becomes blurred, and the porous layer becomes transparent by absorbing liquid and the blue color due to the support is visible. Will be done.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the bleeding red dot pattern due to the colored layer is visible, and water has adhered in the past. I was able to determine that.
When water adhered to the water discoloration indicator again, the porous layer became transparent due to liquid absorption, and the blue color of the support was visually recognized, and the state in which water was adhered could be repeatedly visually recognized.

Example 1
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP-10, Dainippon] on the surface of blue 100% cotton broad fabric as a support Ink Chemical Industry Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoamer 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate-based cross-linking agent 3 parts The entire surface was solid-printed on a 100-mesh screen plate using a screen printing ink obtained by mixing the above, and dried and cured at 130 ° C. for 5 minutes to form a porous layer.
Next, 1.0 part of phloxine (CI 45410), 45.0 parts of polyvinylpyrrolidone resin (trade name: Socalan K-17, manufactured by BASF), acrylic acid ester resin as a red water-soluble dye on the porous layer. Using a screen printing ink containing 11.1 parts of emulsion [trade name: Movinyl 966A, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 45%] and 45.0 parts of water, a 180 mesh screen plate with a diameter of 2 mm The dot pattern was printed and dried and cured at 100 ° C. for 5 minutes to form a colored layer to obtain a water discoloration indicator.

When the back surface (support side) of the water discoloration indicator was fixed to the joint portion of the pipe using a binding band and put into practical use, under normal conditions (non-water absorption state), white due to the porous layer and red due to the colored layer The dot pattern is visible, but when water adheres from the front or back surface of the indicator, the water-soluble dye contained in the colored layer elutes to the surroundings, the dot pattern becomes blurred, and the porous layer absorbs liquid. It becomes transparent and the blue color due to the support is visible.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the bleeding red dot pattern due to the colored layer is visible, and water has adhered in the past. I was able to determine that.
When water adhered to the water discoloration indicator again, the porous layer became transparent due to liquid absorption, and the blue color of the support was visually recognized, and the state in which water was adhered could be repeatedly visually recognized.
Further, even if the water discoloration indicator is left in an environment of 30 ° C. and 85% humidity for 72 hours, the colored layer can retain the dot pattern before getting wet, and has excellent storage stability in the initial state. Met.

Example 2
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP-10, Dainippon] on the surface of blue 100% cotton broad fabric as a support Ink Chemical Industry Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoamer 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate-based cross-linking agent 3 parts The entire surface was solid-printed on a 100-mesh screen plate using a screen printing ink obtained by mixing the above, and dried and cured at 130 ° C. for 5 minutes to form a porous layer.
Next, 1.0 part of floxin (CI 45410), 35.0 parts of polyvinylpyrrolidone resin (trade name: Socalan K-17, manufactured by BASF), acrylic acid ester resin as a red water-soluble dye on the porous layer. Using a screen printing ink containing 32.6 parts of emulsion [trade name: Movinyl 966A, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 45%] and 35.0 parts of water, a 180 mesh screen plate with a diameter of 2 mm The dot pattern is printed and dried and cured at 100 ° C. for 5 minutes to form a colored layer. Further, a colorless and transparent polyethylene terephthalate film (thickness 25 μm) is formed on the porous and colored layer and is water-insoluble made of an acrylic resin. A waterproof layer was formed by sticking it on the entire surface using an adhesive to obtain a water discoloration indicator.

When the back surface (support side) of the water discoloration indicator was fixed to the joint portion of the pipe using a binding band and put into practical use, under normal conditions (non-water absorption state), white due to the porous layer and red due to the colored layer The dot pattern is visible, but when water adheres from the back surface of the indicator, the water-soluble dye contained in the colored layer elutes to the surroundings, the dot pattern becomes bleeding, and the porous layer becomes transparent by absorbing liquid. The blue color of the support is visible.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the bleeding red dot pattern due to the colored layer is visible, and water has adhered in the past. I was able to determine that.
When water adheres to the water discoloration indicator from the back surface again, the porous layer becomes transparent by absorbing liquid and the blue color due to the support can be visually recognized, and the state in which water adheres can be repeatedly visually recognized, and the water adhered from the front surface can be visually recognized. Is not detected, but only the water adhering from the back surface is detected, so it was useful as an indicator to detect the presence or absence of water leakage from the joint part.
Further, even if the water discoloration indicator is left in an environment of 30 ° C. and 85% humidity for 72 hours, the colored layer can retain the dot pattern before getting wet, and has excellent storage stability in the initial state. Met.

Example 3
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP-10, Dainippon] on the surface of blue 100% cotton broad fabric as a support Ink Chemical Industry Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoamer 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate-based cross-linking agent 3 parts The entire surface was solid-printed on a 100-mesh screen plate using a screen printing ink obtained by mixing the above, and dried and cured at 130 ° C. for 5 minutes to form a porous layer.
Next, 1.0 part of floxin (CI 45410), 25.0 parts of polyvinylpyrrolidone resin (trade name: Socalan K-17, manufactured by BASF), acrylic acid ester resin as a red water-soluble dye on the porous layer. Using a screen printing ink containing 55.6 parts of emulsion [trade name: Movinyl 966A, manufactured by Nippon Synthetic Chemical Co., Ltd., solid content 45%] and 25.0 parts of water, a 180 mesh screen plate with a diameter of 2 mm Dot pattern is printed and dried and cured at 100 ° C. for 5 minutes to form a colored layer, and a colorless and transparent polyethylene terephthalate film (thickness 25 μm) is further applied on the porous and colored layer in water-insoluble material made of acrylic resin. A waterproof layer was formed by sticking it on the entire surface using an adhesive.
Next, a water-insoluble adhesive layer made of a dot-shaped acrylic resin was provided on the back surface of the support to obtain a water discoloration indicator.

When the adhesive layer side of the water discoloration indicator was attached to the joint portion of the pipe and put into practical use, a white dot pattern due to the porous layer and a red dot pattern due to the colored layer were visually recognized in the normal state (non-water absorption state). However, when water adheres from the back surface of the indicator, the water-soluble dye contained in the colored layer elutes to the surroundings and the dot pattern becomes blurred, and the porous layer becomes transparent by absorbing liquid and the blue color due to the support becomes. It is visually recognized.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the bleeding red dot pattern due to the colored layer is visible, and water has adhered in the past. I was able to determine that.
When water adheres to the water discoloration indicator from the back surface again, the porous layer becomes transparent by absorbing liquid, the blue color due to the support is visually recognized, and the state in which water is adhered can be repeatedly visually recognized.
Since it does not detect water adhering from the front surface but only water adhering from the back surface, it was useful as an indicator for detecting the presence or absence of water leakage from the joint portion.
Further, even if the water discoloration indicator is left in an environment of 30 ° C. and 85% humidity for 72 hours, the colored layer can retain the dot pattern before getting wet, and has excellent storage stability in the initial state. Met.

Example 4 (see FIG. 2)
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP-10, Dainippon Ink Chemicals] on the surface of red polyethylene terephthalate film as support 2. Made by Kogyo Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate-based cross-linking agent 3 parts mixed Ink for screen printing, 1.0 part of Brilliant Blue FCF-L (CI 42090) as a blue water-soluble dye, polyvinyl alcohol resin [Product name: Gosenol KL-03, manufactured by Nippon Synthetic Chemical Co., Ltd. ] A checkered pattern is printed on a 150-mesh screen plate using a screen printing ink containing 30 parts and 70 parts of water, dried and cured at 60 ° C. for 30 minutes, and the porous layer 3 and the colored layer 4 are arranged side by side. Then, the water discoloration indicator 1 was obtained.

When the back surface (support side) of the water discoloration indicator was attached to the pipe and put into practical use, a white checkered pattern due to the porous layer and a blue checkered pattern due to the colored layer were visually recognized in the normal state (non-water absorption state). When water adheres from the surface of the indicator, the water-soluble dye contained in the colored layer elutes to the surroundings and becomes bleeding, and the porous layer becomes transparent by absorbing liquid, and the red color due to the support is visually recognized.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the blurred blue squares due to the colored layer are visible, and water has adhered in the past. Was able to be determined.
When water adhered to the water discoloration indicator again, the porous layer became transparent due to liquid absorption, and the red color due to the support was visually recognized, and the state in which water was adhered could be repeatedly visually recognized.

Example 5
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP] on the surface of red T / C (65/35) broad cloth as a support -10, manufactured by Dainippon Ink Chemical Industry Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate Screen printing ink made by mixing 3 parts of system cross-linking agent, 1.0 part of Brilliant Blue FCF-L (CI 42090) as a blue water-soluble dye, polyvinyl alcohol resin [trade name: Gosenol KL-03, Using screen printing ink containing 28.5 parts of Nippon Synthetic Chemical Co., Ltd., urethane resin emulsion [trade name: Hydran HW920, solid content 50%, manufactured by DIC Corporation] 3 parts, and 71.5 parts of water. Then, a checkered pattern was printed on a 100-mesh screen plate, dried and cured at 110 ° C. for 5 minutes, and a porous layer and a colored layer were arranged side by side to obtain a water discoloration indicator.

When the back surface (support side) of the water discoloration indicator was attached to the pipe and put into practical use, a white checkered pattern due to the porous layer and a blue checkered pattern due to the colored layer were visually recognized in the normal state (non-water absorption state). When water adheres from the front or back surface of the indicator, the water-soluble dye contained in the colored layer elutes to the surroundings and becomes bleeding, and the porous layer becomes transparent by water absorption and the red color due to the support is visible. Will be done.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the blurred blue squares due to the colored layer are visible, and water has adhered in the past. Was able to be determined.
When water adhered to the water discoloration indicator again, the porous layer became transparent due to liquid absorption, and the red color due to the support was visually recognized, and the state in which water was adhered could be repeatedly visually recognized.
Further, even if the water discoloration indicator was left for 72 hours in an environment of 30 ° C. and 85% humidity, the checkered pattern before getting wet could be maintained, and the storage stability in the initial state was also excellent. ..

Example 6
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP] on the surface of red T / C (65/35) broad cloth as a support -10, manufactured by Dainippon Ink Chemical Industry Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate Screen printing ink made by mixing 3 parts of the system cross-linking agent, 1.0 part of Brilliant Blue FCF-L (CI 42090) as a blue water-soluble dye, polyvinyl alcohol resin [trade name: Gosenol KL-03, Using screen printing ink containing 25.5 parts of Nippon Synthetic Chemical Co., Ltd., urethane resin emulsion [trade name: Hydran HW920, solid content 50%, DIC Co., Ltd.] 9 parts, 74.5 parts of water Then, a checkered pattern is printed on a 100-mesh screen plate and dried and cured at 110 ° C. for 5 minutes to arrange a porous layer and a colored layer side by side, and further, a colorless and transparent soft poly on the porous and colored layers. A vinyl chloride film (thickness 0.2 mm) was attached to the entire surface using a water-insoluble adhesive made of acrylic resin to form a waterproof layer, and a water discoloration indicator was obtained.

When the back surface (support side) of the water discoloration indicator was attached to the joint portion of the pipe and put into practical use, a white checkered pattern due to the porous layer and a blue checkered pattern due to the colored layer were visually visible in the normal state (non-water absorption state). However, when water adheres from the back surface of the indicator, the water-soluble dye contained in the colored layer elutes to the surroundings and becomes bleeding, and the porous layer becomes transparent by water absorption and the red color due to the support becomes red. It is visually recognized.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the blurred blue squares due to the colored layer are visible, and water has adhered in the past. Was able to be determined.
When water adheres to the water discoloration indicator from the back surface again, the porous layer becomes transparent by absorbing liquid and the red color due to the support can be visually recognized, and the state in which water adheres can be repeatedly visually recognized, and the water adhered from the front surface can be visually recognized. Is not detected, but only the water adhering from the back surface is detected, so it was useful as an indicator to detect the presence or absence of water leakage from the joint part.
Further, even if the water discoloration indicator is left in an environment of 30 ° C. and 85% humidity for 72 hours, the colored layer can retain the checkered pattern before getting wet and has excellent storage stability in the initial state. Met.

Reference example 2 (see Fig. 3)
On the surface of pink synthetic paper as the support 2, 0.5 part of acid blue PG (CI 42655) as a blue water-soluble dye, hydroxypropyl cellulose resin [trade name: HPC-L, manufactured by Nippon Soda Co., Ltd.] Using a screen printing ink containing 20.0 parts and 80.0 parts of water, solid printing was performed on a 180-mesh screen plate, and the mixture was dried and cured at 70 ° C. for 30 minutes to form a colored layer 4, and an upper layer thereof was formed. Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, vinyl chloride / vinyl acetate modified resin [trade name: solvent AL, manufactured by Nissin Chemical Industry Co., Ltd.] 10 Using a screen printing ink made by mixing 15 parts of petroleum-based aromatic hydrocarbon solvent [trade name: Solbesso 100, manufactured by Exxon Mobile Co., Ltd.], 25 parts of cyclohexanone, and 0.5 parts of surfactant. The entire surface was solid-printed on a 100-mesh screen plate and dried and cured at 60 ° C. for 30 minutes to form a porous layer 3 to obtain a water discoloration indicator 1.

When the back surface (support side) of the water discoloration indicator was attached to a pipe and put into practical use, white color due to the porous layer was visually recognized in the normal state (non-water absorption state), but when water adhered from the indicator surface, The porous layer becomes transparent by absorbing liquid, and purple, which is a mixture of the pink color of the support and the blue color of the colored layer, is visually recognized, and the water-soluble dye contained in the colored layer is eluted into the upper porous layer.
The indicator with water adhered shows the above-mentioned aspect, but when the porous layer dries, only the blue color of the eluted water-soluble dye is visible, and the water adhered state and the dried state after water adhered. The colors are different, and it is possible to determine the current state of water adhesion.
When water adhered to the water discoloration indicator again, the porous layer became transparent by absorbing liquid, and the mixed color purple of the support and the colored layer was visually recognized, and the state in which water was adhered could be repeatedly visually recognized.

Reference example 3 (see Fig. 4)
As the support 2, a non-discoloring colored layer 5 having a dot pattern having water resistance was provided on the surface of a white T / C broad cloth using a pink printing ink.
Next, 0.5 part of acid blue PG (CI 42655) as a blue water-soluble dye on the non-discoloring colored layer, hydroxypropyl cellulose resin [trade name: HPC-L, manufactured by Nippon Soda Co., Ltd.] 20 Using a screen printing ink containing 0.0 parts and 80.0 parts of water, solid printing was performed on a 180 mesh screen plate, and the mixture was dried and cured at 130 ° C. for 5 minutes to form a colored layer 4, and further on the upper layer. Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, vinyl chloride / vinyl acetate modified resin [trade name: Solvent AL, manufactured by Nissin Chemical Industry Co., Ltd.] 10 parts , Petroleum-based aromatic hydrocarbon solvent [trade name: Solbesso 100, manufactured by Exxon Mobile Co., Ltd.] 100 parts using screen printing ink made by mixing 15 parts, cyclohexanone 25 parts, and surfactant 0.5 parts. The entire surface was solid-printed on a mesh screen plate and dried and cured at 100 ° C. for 5 minutes to form a porous layer 3 to obtain a water discoloration indicator 1.

When the back surface (support side) of the water discoloration indicator was attached to a pipe and put into practical use, white color due to the porous layer was visually recognized in the normal state (non-water absorption state), but water adhered from the front surface or the back surface of the indicator. Then, the porous layer becomes transparent by absorbing liquid, and the purple dot pattern in which the pink color of the non-discoloring colored layer and the blue color of the colored layer are mixed and the blue color of the colored layer are visually recognized and included in the colored layer. The water-soluble dye is eluted in the upper porous layer.
The indicator in the state where water is attached shows the above-mentioned aspect, but when the porous layer dries, only the blue color of the eluted water-soluble dye is visible, and the state before water is attached and the state where water is attached and After the water adhered, the dried state had different appearances, and it was possible to distinguish between the past adhered state and the current adhered state of water.

Example 7
On the surface of pink T / C broad cloth as a support, 1.0 part of acid blue PG (CI 42655) as a blue water-soluble dye, polyvinylpyrrolidone resin (trade name: Socalan K-17, manufactured by BASF) 25 .0 parts, acrylic acid ester resin emulsion 55.6 parts [trade name: Movinyl 966A, solid content 45%, manufactured by Nippon Synthetic Chemical Co., Ltd.], 180 parts using screen printing ink containing 25.0 parts of water. A dot pattern is printed on a mesh screen plate and dried and cured at 130 ° C. for 5 minutes to form a colored layer, and a wet method fine particle silica [trade name: Nipseal E-220, Nippon Silica Industry Co., Ltd.] is further formed on the upper layer. [Manufactured] 15 parts, Vinyl chloride / vinyl acetate modified resin [Product name: Solvine AL, manufactured by Nisshin Kagaku Kogyo Co., Ltd.] 10 parts, Petroleum-based aromatic hydrocarbon solvent [Product name: Solbesso 100, Exxon Mobile Co., Ltd. )] Using a screen printing ink made by mixing 15 parts, 25 parts of cyclohexanone, and 0.5 part of a surfactant, the entire surface is solid-printed on a 100-mesh screen plate and dried and cured at 100 ° C. for 5 minutes. A porous layer was formed to obtain a water discoloration indicator.

When the back surface (support side) of the water discoloration indicator was attached to the pipe and put into practical use, white color due to the porous layer was visually recognized in the normal state (non-water absorption state), but water adhered from the front surface or the back surface of the indicator. Then, the porous layer becomes transparent by absorbing liquid, blue elutes from the colored layer, and a purple blurred dot pattern mixed with the underlying pink color is visually recognized.
The indicator with water adhered shows the above-mentioned aspect, but only the blurred blue dot pattern in which the porous layer dries is visible, and the water adhered state and the dried state after water adhered. The states were different, and the appearances were different before the water adhered, when the water adhered, and when the water adhered and then dried, and it was possible to discriminate between the past adhesion state and the current water adhesion state.
Further, even if the water discoloration indicator is left in an environment of 30 ° C. and 85% humidity for 72 hours, the water-soluble dye in the colored layer does not migrate to the porous layer, and the storage stability in the initial state is excellent. It was a dye.

Reference example 4
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP-10, Dainippon Ink Chemical Industry Co., Ltd.] on the surface of blue polyethylene terephthalate film as a support Made by Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoamer 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate-based cross-linking agent 3 parts are mixed. The entire surface was solid-printed on a 100-mesh screen plate using the above ink for screen printing, and dried and cured at 60 ° C. for 30 minutes to form a porous layer.
Next, an ink containing 1.0 part of phloxine (CI 45410) and 99.0 parts of water as a red water-soluble dye was filled on the porous layer in a spray gun having a diameter of 0.4 mm, and a pattern paper was used. The heart pattern was spray-painted and dried and cured at room temperature for 60 minutes to form a colored layer to obtain a water discoloration indicator.

When the back surface (support side) of the water discoloration indicator was attached to the pipe and put into practical use, a white color due to the porous layer and a red heart pattern due to the colored layer were visually recognized in the normal state (non-water absorption state). When water adheres from the indicator surface, the water-soluble dye contained in the colored layer elutes to the surroundings and the heart pattern becomes blurred, and the porous layer becomes transparent by water absorption and the blue color due to the support is visible. Will be done.
The indicator with water attached shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the red heart pattern that is blurred by the colored layer is visible, and water has adhered in the past. I was able to determine that.

Reference example 5
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP-10, Dainippon Ink Chemical Industry Co., Ltd.] on the surface of blue polyethylene terephthalate film as a support Made by Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoamer 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate-based cross-linking agent 3 parts are mixed. The entire surface was solid-printed on a 100-mesh screen plate using the above ink for screen printing, and dried and cured at 60 ° C. for 30 minutes to form a porous layer.
Next, on the porous layer, 5.0 parts of a red water-dispersed pigment [trade name: TC Rubin FR-H, manufactured by Dainichi Seika Kogyo Co., Ltd.], polyvinylpyrrolidone resin (trade name: Socalan K-17, manufactured by BASF) ) Using a screen printing ink containing 50.0 parts and 50.0 parts of water, a dot pattern with a diameter of 2 mm is printed on a 180 mesh screen plate and dried and cured at 50 ° C. for 30 minutes to form a colored layer. And obtained a water discoloration indicator.

When the back surface (support side) of the water discoloration indicator was attached to the pipe and put into practical use, a white dot pattern due to the porous layer and a red dot pattern due to the colored layer were visually recognized in the normal state (non-water absorption state). When water adheres from the surface of the indicator, the pigment contained in the colored layer diffuses to the surroundings as the polyvinylpyrrolidone resin dissolves, and the dot pattern becomes blurred, and the porous layer becomes transparent by water absorption to support the support. The blue color is visible.
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the bleeding red dot pattern due to the colored layer is visible, and water has adhered in the past. I was able to determine that.

Example 8
Wet method fine particle silica [trade name: Nipseal E-220, manufactured by Nippon Silica Industry Co., Ltd.] 15 parts, urethane emulsion [trade name: Hydran AP] on the surface of blue T / C (65/35) broad cloth as a support -10, manufactured by Dainippon Ink Chemical Industry Co., Ltd., solid content 30%] 45 parts, water 40 parts, silicone-based defoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part, isocyanate Screen printing ink made by mixing 3 parts of system cross-linking agent, red water dispersion pigment [trade name: TC Rubin FR-H, manufactured by Dainichi Seika Kogyo Co., Ltd.] 5.0 parts, polyvinylpyrrolidone resin (trade name) : Sokaran K-17, manufactured by BASF) 45.0 parts, water 50.0 parts, urethane resin emulsion [trade name: Hydran HW920, solid content 50%, manufactured by DIC Corporation] 10 parts, water 55.0 parts A checkered pattern was printed on a 100-mesh screen plate using the included screen printing ink, dried and cured at 110 ° C. for 5 minutes, and a porous layer and a colored layer were arranged side by side to obtain a water discoloration indicator.

When the back surface (support side) of the water discoloration indicator was attached to the pipe and put into practical use, a white checkered pattern due to the porous layer and a red checkered pattern due to the colored layer were visually recognized in the normal state (non-water absorption state). When water adheres from the front or back surface of the indicator, the pigment contained in the colored layer diffuses to the surroundings and becomes bleeding, and the porous layer becomes transparent by water absorption, and the blue color due to the support is visually recognized. ..
The indicator with water adhering shows the above-mentioned aspect, but when the porous layer dries, it returns to the original white state, and only the red squares that are blurred by the colored layer are visible, and water has adhered in the past. Was able to be determined.
When water adhered to the water discoloration indicator again, the porous layer became transparent due to liquid absorption, and the blue color of the support was visually recognized, and the state in which water was adhered could be repeatedly visually recognized.
Further, even if the water discoloration indicator is left in an environment of 30 ° C. and 85% humidity for 72 hours, the colored layer can retain the checkered pattern before getting wet and has excellent storage stability in the initial state. Met.

1 Water discoloration indicator 2 Support 3 Porous layer 4 Colored layer 5 Non-discolorable colored layer

Claims (10)

A porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state on a support, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state, and water can be used on the porous layer. Ri coloring layer solubilizing name partially provided, a colored layer of solubilized by the water, a layer containing a water-soluble dye and a binder resin, water wherein the binder resin containing a water-soluble resin and water insoluble resin Discoloration indicator. On the support, a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersed state, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state, and a colored layer which is solubilized in water are arranged in parallel. Water discoloration indicator provided. A colored layer that is solubilized with water and a low-refractive-index pigment fixed to the binder resin in a dispersed state on the support, which is opaque in a non-liquid absorbing state and becomes transparent in a liquid absorbing state. Ri Na providing a porous layer, a colored layer of solubilized by the water, a layer containing a water-soluble dye and a binder resin, wherein the binder resin is water-metachromatic indicator comprising a water-soluble resin and water insoluble resin. The water discoloration indicator according to claim 2, wherein the colored layer solubilized with water is a layer containing a water-soluble dye. The water discoloration indicator according to claim 4, wherein the colored layer solubilized with water is a layer containing a water-soluble dye and a binder resin. The water discoloration indicator according to claim 5, wherein the binder resin contains a water-soluble resin and a water-insoluble resin. The water discoloration indicator according to any one of claims 1 to 6, wherein the support is a water-permeable support. The water discoloration indicator according to claim 7, wherein a waterproof layer is provided on the uppermost layer. The water discoloration indicator according to any one of claims 1 to 8, wherein a non-discoloration coloring layer is provided on the support. The water discoloration indicator according to any one of claims 1 to 9, wherein an adhesive layer is provided on the bottom layer.

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