Water-color-changing organisms, water-color-changing organism set

Abstract

To provide a water discoloration body and a water discoloration body set which cover a water discoloration image with a cover member immediately after forming the water discoloration image by bonded with water, and thereby can extend a water discoloration image keeping time, and can confirm whether the water discoloration image has been formed in a good balance manner.SOLUTION: There are provided a water discoloration body 1 that includes a water discoloration sheet 2 having a porous layer in which a low refractive index pigment is fixed to a binder resin in a dispersion state provided on an upper layer of a colored layer, and a transparent cover member 6 which covers a water discoloration image formed by bonding water to the surface of the porous layer, suppresses drying of water and delays disappearance of the water discoloration image, wherein the transparent cover member includes a character sample 9 formed in the water discoloration sheet; and a water discoloration body set which includes the water discoloration body and a water bonding tool for forming a water discoloration image.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water discoloration body and a water discoloration body set. More specifically, it relates to a water discoloration body and a water discoloration body set including a water discoloration sheet and a cover member that delays the disappearance of a water discoloration image formed on the water discoloration sheet.

Background Art

[0002] Conventionally, a water discoloration body has been disclosed in which a porous layer in which a low refractive index pigment that is opaque in a non-absorbent state and becomes transparent in an absorbent state is fixed in a dispersed state in a binder resin is disposed on a colored layer. Immediately after forming a water discoloration image by attaching water with a writing implement, stamp tool, finger, etc., a water discoloration material set has been disclosed that extends the maintenance time of the water discoloration image by covering the water discoloration image with a cover member (see, for example, Patent Document 1). The water discoloration material set can extend the maintenance time of the water discoloration image and can satisfy the practicality for toys and teaching tools.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention aims to provide a water discoloration body and a water discoloration body set that can extend the maintenance time of a water discoloration image formed on this type of water discoloration material and can confirm whether the water discoloration image is formed in a well-balanced manner.

Means for Solving the Problems

[0005] The present invention comprises a water-color-changing sheet having a porous layer on top of a colored layer in which a low refractive index pigment is dispersed and fixed in a binder resin, and a transparent cover member that covers the water-color-changing image formed by the adhesion of water to the surface of the porous layer, suppresses the drying of the water, and delays the disappearance of the water-color-changing image. The lower surface of the transparent cover member has at least three non-linearly arranged point-shaped protrusions that maintain a non-contact state between the water-color-changing sheet surface and the transparent cover member, and these protrusions have a height of 0.4 mm to 12.0 mm, and the surface area s(mm) of the protrusions visible from the upper surface of the transparent cover member is... 2 ) and the height h (mm) of the protrusion satisfy the following formula (1), and the area occupied by the protrusion visible from the top surface of the transparent cover member is 10% or less of the surface area of ​​the top surface of the transparent cover member. The transparent cover member has water-resistant properties. Color A model of the character to be formed is provided. Furthermore, the color of the porous layer in its dry state, the color of the water-color-changing image, and the color of the sample are all different. A water-color-changing sheet having a porous layer on top of a colored layer in which a water-color-changing body or a low refractive index pigment is dispersed and fixed in a binder resin, and a transparent cover member that covers the water-color-changing image formed by the adhesion of water to the surface of the porous layer, suppresses the drying of the water, and delays the disappearance of the water-color-changing image, and the water-color-changing Color A model of the character to be formed is provided. Furthermore, the lower surface of the transparent cover member has at least three non-linearly arranged point-shaped protrusions that contact the surface of the water-color-changing sheet, maintaining a non-contact state between the transparent cover member and the surface of the water-color-changing sheet. The protrusions have a height of 0.4 mm to 12.0 mm, and the surface area s(mm²) of the protrusions visible from the upper surface of the transparent cover member is... 2 ) and the height h (mm) of the protrusions satisfy the following formula (1), the area occupied by the protrusions visible from the top surface of the transparent cover member is 10% or less of the surface area of ​​the top surface of the transparent cover member, and the porous layer has different colors in its dry state, in its water-color-changed image, and in its sample color. It requires a water-color-changing substance. 1.0 ≤ s / h ≤ 400 (1) Furthermore ,before The protrusion is transparent, the protrusion is white, the tip of the protrusion is curved, the transparent cover member is flexible, and the protrusion is 100 cm 2 Each has three or more, the surface of the transparent cover member is non-glossy, and the surface of the transparent sample sheet is non-glossy. ,before The transparent cover member is attached to the water-color-changing sheet at one end and has the other end as a free end, and is provided on the water-color-changing sheet so as to be openable and closable; it consists of a plurality of the water-color-changing sheets and a plurality of the transparent cover members; it consists of a plurality of the water-color-changing sheets, a plurality of the transparent cover members and a plurality of the transparent sample sheets; and the light transmittance of the sample is 20 to 99%. The aforementioned point-shaped protrusions are arranged in a grid pattern. The following are among the requirements. Furthermore, the requirements include a water-color-changing body set that includes the aforementioned water-color-changing body and a water-adhering device for forming a water-color-changing image. [Effects of the Invention]

[0006] The present invention provides a water-color-changing body and a water-color-changing body set that satisfy the commerciality and practicality of a toy or training tool, as it allows for the easy extension of the duration of a water-color-changing image by covering it with a cover member immediately after applying water with a writing instrument, stamping tool, or fingers to form a water-color-changing image, and also allows for confirmation of whether the water-color-changing image has been formed in a balanced manner. [Brief explanation of the drawing]

[0007] [Figure 1] This is a top view showing a water-color-changing material according to one embodiment of the present invention. [Figure 2] Figure 1 is a side view of a water-chromogenic organism. [Figure 3] This is a top view showing a water-color-changing material in another embodiment of the present invention. [Figure 4] Figure 3 is a side view of a water-color-changing material. [Figure 5] This is a side view showing a water-chromogenic example. [Figure 6] This is a side view showing another example of a water-chromogenic body. [Figure 7] This is a top view of a water-color-changing device set according to one embodiment of the present invention. [Modes for carrying out the invention]

[0008] The water-color-changing sheet has a porous layer on top of the colored layer in which a low refractive index pigment is dispersed and fixed in a binder resin. The colored layer may be the support itself, but it is preferable to provide a colored layer (including an image of any shape) on the surface of the support. The support can be made of paper, synthetic paper, woven fabrics, knitted fabrics, braided fabrics, nonwoven fabrics, natural or synthetic leather, plastic, glass, ceramics, metal, wood, stone, etc. While a flat shape is preferred, an uneven or textured shape is also acceptable. The colored layer provided on the surface of the support is formed from a binder resin containing a coloring agent. Examples of the aforementioned colorants include general dyes, general pigments, fluorescent dyes, fluorescent pigments, and metallic luster pigments. The aforementioned coloring agent is formed by applying an ink or paint contained in a vehicle containing a binder resin as a binder to a support, and then drying the volatile components to form a colored layer. Examples of the binder resin include urethane resins, nylon resins, vinyl acetate resins, acrylic acid ester resins, acrylic acid ester copolymer resins, acrylic polyol resins, vinyl chloride-vinyl acetate copolymer resins, maleic acid resins, polyester resins, styrene resins, styrene copolymer resins, polyethylene resins, polycarbonate resins, epoxy resins, styrene-butadiene copolymer resins, acrylonitrile-butadiene copolymer resins, methyl methacrylate-butadiene copolymer resins, butadiene resins, chloroprene resins, melamine resins, and emulsions of the above resins, casein, starch, cellulose derivatives, polyvinyl alcohol, urea resins, phenolic resins, and the like. The colored layer is formed on a support by printing methods such as process printing, screen printing, offset printing, gravure printing, coater, pad printing, inkjet printing, and transfer, as well as by brush painting, spray painting, electrostatic painting, electrodeposition painting, pouring, roller painting, and dipping. Alternatively, a transfer layer can be formed by first applying an ink or paint contained in a vehicle containing a coloring agent and a binder resin as a binder onto a separate substrate, and then transferring the transfer layer onto a support to form a colored layer. Furthermore, if the support is transparent, a colored layer can be provided on the back surface of the support (the side without the porous layer).

[0009] A water-color-changing sheet can be obtained by laminating a porous layer on the aforementioned colored layer, in which a low refractive index pigment is dispersed and fixed by a binder resin. The porous layer is a layer in which a low refractive index pigment is fixed in a dispersed state together with a binder resin, and is a layer whose transparency differs between the dry state and the liquid-absorbing state. Examples of the low refractive index pigments include silica and its salts, barite powder, barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, talc, alumina white, and magnesium carbonate, which have a refractive index in the range of 1.4 to 1.8 and exhibit good transparency when they absorb water. Examples of silicic acid salts include aluminum silicate, potassium aluminum silicate, sodium aluminum silicate, calcium aluminum silicate, potassium silicate, calcium silicate, sodium calcium silicate, sodium silicate, magnesium silicate, potassium magnesium silicate, and potassium magnesium silicate. Silicic acid is a suitable low-refractive-index pigment. Furthermore, two or more types of low refractive index pigments can be used in combination. The particle size of the low refractive index pigment is not particularly limited, but particles of 0.03 to 10.0 μm are preferably used. The silicic acid mentioned above may be silicic acid produced by a dry process, but silicic acid produced by a wet process (hereinafter referred to as wet-processed silicic acid) is particularly effective. To explain this point, silicic acid is produced as amorphous silicic acid, and is broadly classified into two types depending on the production method: dry process, which uses a gas-phase reaction such as the thermal decomposition of silicon halides such as silicon tetrachloride (hereinafter referred to as dry-processed silicic acid), and wet process, which uses a liquid-phase reaction such as decomposition with an acid such as sodium silicate. Dry-processed silicic acid and wet-processed silicic acid have different structures. Dry-processed silicic acid forms a three-dimensional structure in which silicic acid molecules are densely bonded, while wet-processed silicic acid has a so-called two-dimensional structure in which silicic acid molecules are condensed to form a long molecular arrangement. Therefore, since the molecular structure is coarser compared to the dry-processed silica, it is presumed that when wet-processed silica is applied to a porous layer, it exhibits superior diffuse reflectivity of light in a dry state and greater opacity under normal conditions compared to systems using dry-processed silica. Furthermore, since the porous layer absorbs water, wet-processed silica has more hydroxyl groups present as silanol groups on the particle surface compared to dry-processed silica, resulting in a greater degree of hydrophilicity, and is therefore preferable for use. Furthermore, in order to adjust the opacity of the porous layer under normal conditions and its transparency under liquid absorption conditions, other low refractive index pigments can be used in combination with wet-process silica.

[0010] The low refractive index pigment in the porous layer depends on properties such as particle size, specific surface area, and oil absorption capacity, but to satisfy both opacity under normal conditions and transparency under liquid absorption, the application amount should be 1 to 50 g / m². 2 Preferably, and more preferably, 5 to 50 g / m 2 It is 1 g / m 2 Below 50g / m², it is difficult to obtain sufficient concealment under normal conditions, and 2 Beyond a certain point, it becomes difficult to achieve sufficient transparency during liquid absorption. The low refractive index pigment is dispersed in a vehicle containing a binder resin as a binder, and after being coated onto a support, the volatile components are dried to form a porous layer. Examples of the binder resin include urethane resins, nylon resins, vinyl acetate resins, acrylic acid ester resins, acrylic acid ester copolymer resins, acrylic polyol resins, vinyl chloride-vinyl acetate copolymer resins, maleic acid resins, polyester resins, styrene resins, styrene copolymer resins, polyethylene resins, polycarbonate resins, epoxy resins, styrene-butadiene copolymer resins, acrylonitrile-butadiene copolymer resins, methyl methacrylate-butadiene copolymer resins, butadiene resins, chloroprene resins, melamine resins, and emulsions of the above resins, casein, starch, cellulose derivatives, polyvinyl alcohol, urea resins, phenolic resins, and the like. The mixing ratio of the low refractive index pigment and the binder resin depends on the type and properties of the low refractive index pigment, but is preferably 0.5 to 2 parts by mass of binder resin solids per 1 part by mass of low refractive index pigment, and more preferably 0.8 to 1.5 parts by mass. If the binder resin solids are less than 0.5 parts by mass per 1 part by mass of low refractive index pigment, it is difficult to obtain practical film strength for the porous layer, and if they exceed 2 parts by mass, the permeability of water into the porous layer is easily impaired. The aforementioned porous layer has a lower mixing ratio of binder resin to colorant compared to general coating films, making it difficult to obtain sufficient film strength. Therefore, to improve abrasion resistance, it is effective to use nylon resin or urethane resin among the binder resins mentioned above. Examples of the aforementioned urethane resins include polyester-based urethane resins, polycarbonate-based urethane resins, and polyether-based urethane resins, and two or more types can be used in combination. In addition, urethane emulsion resins in which the aforementioned resin is emulsified and dispersed in water, or colloidal dispersion type (ionomer type) urethane resins that self-emulsify without the need for an emulsifier due to the ionic groups of the ionic urethane resin (urethane ionomer) itself and are dissolved or dispersed in water can also be used. The urethane resin can be either a water-based or oil-based urethane resin, but a water-based urethane resin, particularly a urethane emulsion resin or a colloid-dispersed urethane resin, is preferred. The aforementioned urethane resin can be used alone, but other binder resins can also be used in combination depending on the performance required for the coating. When using binder resins other than urethane resins, it is preferable to include 30% or more of the urethane resin in the binder resin of the porous layer by solid content mass ratio in order to obtain practical coating strength. In the aforementioned binder resin, the film strength can be further improved by adding any crosslinking agent to the crosslinking agent. The aforementioned binder resins have varying degrees of affinity for water, but by combining them, the penetration time into the porous layer, the degree of penetration, and the drying speed after penetration can be adjusted. Furthermore, these adjustments can be controlled by adding dispersants or surfactants as appropriate.

[0011] The porous layer can be formed on the colored layer by printing methods such as screen printing, offset printing, gravure printing, coater, pad printing, and transfer, as well as by brush coating, spray coating, electrostatic coating, electrodeposition coating, pour coating, roller coating, and dipping coating.

[0012] Furthermore, a coloring agent can be added to the porous layer to color it in its dry state. Examples of the colorants include general dyes, general pigments, fluorescent dyes, fluorescent pigments, metallic luster pigments, reversible thermochromic compositions, reversible thermochromic microcapsule pigments containing reversible thermochromic compositions, photochromic compositions, and photochromic microcapsule pigments containing photochromic compositions. When fluorescent colorants such as fluorescent dyes and fluorescent pigments are used, the clarity of the color change is excellent. When thermochromic colorants such as reversible thermochromic compositions and reversible thermochromic microcapsule pigments containing reversible thermochromic compositions, and photochromic colorants such as photochromic colorants, photochromic compositions, and photochromic microcapsule pigments containing photochromic compositions are used, a wide range of color changes can be imparted. As the aforementioned reversible thermochromic composition, a reversible thermochromic composition comprising three components—an electron-donating color-developing organic compound, an electron-accepting compound, and an organic compound medium that reversibly causes a color reaction—is preferably used. As the aforementioned photochromic composition, photochromic compounds such as spirooxazine compounds, spiropyran compounds, and diarylethene compounds are preferably used.

[0013] The porous layer of the water-color-changing sheet is provided with a transparent cover member on its surface that covers the water-color-changing image formed by water adhesion to the surface of the porous layer, suppresses the drying of the water, and delays the disappearance of the water-color-changing image. The transparent substrate forming the transparent cover member only needs to have enough transparency to allow the water-color change image to be seen through, and is formed from a plastic sheet material, a plastic molded body, or glass. Furthermore, a colored transparent substrate can also be used. On the lower surface of the transparent cover member (transparent substrate), the surface of the water-color-changing sheet and the transparent cover member are kept in a non-contact state, and at least three or more protrusions that come into contact with the surface of the water-color-changing sheet can be arranged in a non-linear manner. The aforementioned protrusions form a space between the porous layer and the transparent cover member, and prevent the outline of the water-color change image from becoming blurred and unclear by allowing water in the image to diffuse into areas where the transparent cover member is not in contact with the porous image and is not forming an image. By arranging the protrusions in a non-linear manner at least three times, contact between the transparent cover member and the porous layer can be prevented. Furthermore, by having a height of 0.4 mm to 12.0 mm, preferably 0.5 mm to 10.0 mm, the space between the porous layer and the transparent cover member can suppress the drying of water, thereby improving the function of delaying the disappearance of the water-color change image. If the height of the protrusion is less than 0.4 mm, the water-color change image formed on the water-color change sheet is more likely to come into contact with the transparent cover member, which can easily cause significant blurring of the water-color change image and deformation of the image's shape. Furthermore, if the height of the protrusion exceeds 12.0 mm, it becomes difficult to achieve the effect of suppressing water drying, making it difficult to extend the duration of the water-color change image. Furthermore, when varying the height from 0.4 mm to 12.0 mm, 0.4 mm was found to extend the duration of the water-color change image the most. Therefore, the duration of the water-color change image can be adjusted by setting the height of the protrusion. Furthermore, the surface area of ​​the protrusions visible from the upper surface of the transparent cover member s(mm 2 ) And the height of the protrusion h(mm) By satisfying the following equation (1), the water-color change image visible through the transparent cover member can be made visible without the protrusions obstructing the view, and the function of delaying the disappearance of the water-color change image can be achieved. 1.0 ≤ s / h ≤ 4 00 (1) If s / h is less than 1.0, the shape of the protrusions becomes sharp, making them prone to damaging the porous layer, and requiring careful handling. Also, if s / h is 4 When the value exceeds 00, the surface area of ​​the protrusions visible from the upper surface of the transparent cover member increases, making it easier to obstruct the visibility of the water-color change image. Furthermore, the area occupied by the protrusion visible from the upper surface of the cover member relative to the surface area of ​​the upper surface of the cover member. is 1By being 0.0% or less, it is possible to prevent the water discoloration image from being obstructed from view by the convex portion. In addition, the convex portion preferably has transparency, and when the porous layer is white, it preferably exhibits white, and it is possible to prevent the water discoloration image from being obstructed from view by the convex portion. Since the tip of the convex portion has a curved surface shape, it is difficult to damage the porous layer, it is possible to prevent the porous layer from peeling off, and it is easy for even infants to handle. Furthermore, since the transparent cover member has flexibility, the covering and peeling of the transparent cover member can be made easy, and by providing three or more, preferably four or more convex portions per 100 cm 2 it is possible to suitably avoid contact with the water discoloration image during use. Furthermore, the transparent cover body is attached to the water discoloration sheet at one end and has the other end as a free end, and is provided on the water discoloration sheet so as to be openable and closable, thereby improving the convenience of being able to quickly and easily cover the water discoloration image after its formation. Furthermore, by making it a water discoloration body composed of a plurality of water discoloration sheets and a plurality of transparent cover members, another water discoloration Color image can be formed on another sheet before the water discoloration image dries, so that a desired image can be formed quickly. The plurality of water discoloration sheets and the plurality of transparent cover members may be the same number, but a configuration with fewer transparent cover members may also be used. Furthermore, a water discoloration body composed of a plurality of water discoloration sheets and a single transparent cover member can also achieve the same effect. Furthermore, by making it a water discoloration body composed of a plurality of water discoloration sheets, a plurality of transparent cover members, and a plurality of transparent sample sheets to be described later, another water discoloration Color image can be formed on another sheet before the water discoloration image dries, so that a desired image can be formed quickly. The plurality of water discoloration sheets, the plurality of transparent cover members, and the plurality of transparent sample sheets may be the same number, but a configuration in which the transparent cover members and the transparent sample sheets are fewer than the water discoloration sheets may also be used. Furthermore, a water-color-changing body consisting of multiple water-color-changing sheets, a single transparent cover member, and a single transparent sample sheet can achieve the same effect.

[0014] Furthermore, the transparent cover member can be configured such that the peripheral edge of the lower surface of the cover member is in close contact with the surface of the water-color change sheet, while the inner part of the peripheral edge is provided with a void that maintains a non-contact state with the surface of the water-color change sheet. This covers the water-color change image formed by water adhesion on the surface of the porous layer, suppresses the drying of the water, and delays the disappearance of the water-color change image. The height of the aforementioned void is 0.4 mm to 12.0 mm, preferably 0.5 mm to 10.0 mm. This allows the space between the porous layer and the transparent cover member to suppress water drying, thereby improving the function of delaying the disappearance of the water-color change image. If the height is less than 0.4 mm, the water-color change image formed on the water-color change sheet is more likely to come into contact with the transparent cover member, which can easily cause significant blurring of the water-color change image and deformation of the image's shape. If the height exceeds 12.0 mm, it becomes difficult to suppress the drying of water, making it difficult to extend the duration of the water-color change image.

[0015] The transparent cover member has water-resistant properties. Color A template for characters or other shapes to be formed on the sheet is provided, or a water-resistant coating is applied to the transparent cover member. Color By providing a transparent template sheet on which a model of the characters or other shapes to be formed on the surface is printed or otherwise provided, it is possible to visually confirm whether the water-color change image has been formed according to the template and to check whether the balance of the water-color change image has been formed well. The size, shape, color, line width, and line type of the aforementioned model are not particularly limited, and it may be an outline image or an image formed by multiple dots. Furthermore, the transparent sample sheet used to provide the model can be made from plastic sheet material, plastic molded body, or glass, and the model can be provided by means of printing or other methods. The aforementioned model may include hiragana, katakana, kanji, alphanumeric characters, and various symbols. The surface of the transparent cover member or the transparent sample sheet has fine irregularities and is non-glossy, which prevents light from reflecting off the surface and hindering the visibility of the water-color-changing image. Furthermore, it is possible to trace the water-color-changing image or write other characters or scores on the surface of the transparent cover member or the transparent sample sheet by using erasable writing instruments such as whiteboard markers containing wipeable ink or writing instruments containing water-erasable ink. The aforementioned model has a light transmittance of 20-99%, which allows water to pass through the model formed on the transparent model sheet. strange The characters formed on the colored sheet can be seen, and the model formed on the transparent model sheet and water strange The difference between the text written on the color sheet and the colored sheet can be clearly seen. Furthermore, the light transmittance is preferably 30 to 99%, more preferably 40 to 99%. The aforementioned light transmittance refers to the average transmittance in the wavelength range of 400 to 800 nm. Furthermore, it is preferable that the color of the porous layer in its dry state, the color of the water-color-changing image, and the color of the model are all different, and the model formed on the transparent model sheet and water strange The difference between the text written on the colored sheet and the colored sheet can be seen even more clearly.

[0016] As a means of applying water to the aforementioned water-color-changing sheet, one can wet one's hands or fingers with water and bring them into contact with the sheet, or a water application device can be used. Examples of the water-applying devices include water guns, sprayers, writing or applying tools having a brush tip or fiber pen body at the tip, writing or applying tools that contain water in a container and are equipped with a fiber body or brush for dispensing the water from the container, stamping tools, and the like. A writing instrument or applicator that uses a porous plastic body or a fiber-processed body having continuous pores as the pen tip member, as the water-adhering material, can easily form a written image and enhance practicality. Furthermore, the water-adhering device and the water-color-changing body can be combined to form a water-color-changing body set, which can be used as a training tool set or a drawing toy set. Examples of water-attaching devices include writing instruments and stamping instruments. The writing instrument can be made from individual components such as a brush, a continuous porous plastic body, felt, a resin-processed or fused fiber body, or a plastic with capillary gaps in the internal axial direction. However, a writing instrument in which the component is attached to the barrel as a pen tip and water contained within the barrel can be dispensed is considered practical. The stamping device may be made from a porous plastic body, a plastic molded body with a rough surface to provide wettability, or it may be in the form of a rotating stamp in which the aforementioned component is attached to the outer circumference of a wheel-shaped rotating body. [Examples]

[0017] Examples are shown below, but the present invention is not limited to these examples. In the examples, "parts" refers to parts by mass. Example 1 (See Figures 1 and 2) Preparation of water-chromogenic materials A colored layer 4 was formed on a support 3 made of white synthetic paper by uniformly mixing and stirring a screen printing ink consisting of 5 parts blue pigment, 50 parts acrylic acid ester emulsion (50% by weight solids), 0.2 parts silicone-based defoaming agent, 3 parts thickener, 2 parts wetting agent, 1 part leveling agent, 10 parts water, and 2.5 parts epoxy crosslinking agent using a 180-mesh screen plate. Next, a porous layer 5 was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet process (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This mixture formed a solid print across the entire surface, yielding a water-color-changing sheet 2 measuring 220 mm x 320 mm. Next, on the lower surface of a plate-shaped molded article made of a transparent rigid ABS resin with a thickness of 1.0 mm and a size of 200 mm × 300 mm as the transparent substrate 7, convex portions 8 made of a transparent ABS resin in a conical shape with a diameter of 10 mm and a height of 1.0 mm and a curved tip are provided at three positions corresponding to the vertices of an isosceles triangle. A model 9 of a character ("mountain" in Chinese characters) is provided on the upper surface of the plate-shaped molded article using a transparent red printing ink to obtain a transparent cover member 6. The light transmittance of the model 9 provided on the transparent cover member was 80%. The surface area (s) of the convex portion visually recognized from the upper surface of the transparent cover member was 78.5 mm 2 The height (h) of the convex portion was 1.0 mm, and the surface area (s) of the convex portion / the height (h) of the convex portion was 78.5. Also, the surface area of the upper surface of the transparent cover member was 600 cm 2 The occupied area of the convex portion visually recognized from the upper surface of the transparent cover member was 2.36 cm 2 The ratio of the occupied area of the convex portion visually recognized from the upper surface of the transparent cover member to the surface area of the upper surface of the transparent cover member was 0.39%. A water discoloration body 1 provided with the water discoloration sheet 2 and the transparent cover member 6 was obtained.

[0018] The water discoloration sheet normally exhibits white, but has a fiber pen body at the tip. When writing on the porous layer with a writing body containing water in the shaft cylinder, a blue water discoloration image (character) can be formed. The water discoloration image maintained the image for 5 minutes in an environment of 25°C and 65% RH. However, it gradually disappeared as the moisture evaporated, and at the stage when 10 minutes had passed, it returned to a completely white water discoloration sheet. This phenomenon could be repeated many times. Next, a character "mountain" was written with a writing body containing water on the water discoloration sheet to form a blue water discoloration image, and the transparent cover member was placed on the water discoloration sheet on which the water discoloration image was formed so that the tip of the convex portion contacted the surface of the water discoloration sheet. The water discoloration image could be clearly visually recognized through the transparent cover member, and the transparent cover member did not contact the water discoloration image due to the convex portion, and a clear water discoloration image could be maintained. Furthermore, when a transparent cover is placed so that the water-color-changing image formed on the water-color-changing sheet overlaps with the model, the areas where the blue water-color-changing image and the red model on the transparent cover overlap appear as a mixture of red and blue, resulting in purple, while the areas where they do not overlap appear as their respective colors. This makes it easy to confirm whether the water-color-changing image was formed accurately according to the model. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 30 minutes in an environment of 25°C and 65%RH. Next, when the transparent cover material was removed from the water-color-changing sheet, the water-color-changing pattern gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon could be repeated many times.

[0019] Example 2 (see Figures 3 and 4) Preparation of water-chromogenic materials A colored layer 4 was formed on a support 3, which consisted of a polyester nonwoven fabric on white synthetic paper. The ink was prepared by uniformly mixing and stirring 5 parts of black pigment, 50 parts of acrylic ester emulsion (50% by weight solids), 0.2 parts of silicone-based defoaming agent, 3 parts of thickener, 2 parts of wetting agent, 1 part of leveling agent, 10 parts of water, and 2.5 parts of epoxy-based crosslinking agent. Screen printing was then performed using a 180-mesh screen to create this screen printing ink. Next, a porous layer 5 was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet method (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This mixture formed a solid print across the entire surface, yielding a water-color-changing sheet 2 measuring 280 mm x 380 mm. Next, a transparent cover member 6 was obtained by providing 48 convex portions 8 made of white polyurethane resin, with a diameter of 3 mm and a height of 1.2 mm, and a curved hemispherical shape, at equal intervals of 47 mm on the underside of a flexible polyester transparent sheet 7 with a thickness of 50 μm and dimensions of 253 mm x 353 mm, as a transparent base material 7, in a grid pattern at equal intervals of 47 mm. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 7.07 mm². 2 The height (h) of the protrusion was 1.2 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 5.89. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 893.09 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 3.39 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 0.38%, and per 100 cm 2 The number of protrusions per unit area was 5.37. Furthermore, a transparent template sheet 10 was obtained by providing a template 9 of characters (the kanji characters for "mountain" and "river") on the underside of a flexible polyester transparent sheet 71 with a thickness of 50 μm and dimensions of 233 mm x 333 mm, using transparent vermilion printing ink. The light transmittance of sample 9 provided on the aforementioned transparent sample sheet was 90%. A water-color-changing body was obtained comprising the water-color-changing sheet, the transparent cover member, and the transparent sample sheet.

[0020] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a brush dipped in water, it was possible to form a black water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the characters "mountains and rivers" were written with a Chinese brush dipped in water on the water-discoloring sheet to form a black water-discoloring image, and the transparent cover member was placed on the water-discoloring sheet on which the water-discoloring image was formed so that the tip of the convex portion contacted the surface of the water-discoloring sheet. The water-discoloring image could be clearly visually recognized through the transparent cover member, and the transparent cover member did not contact the water-discoloring image due to the convex portion, and a clear water-discoloring image could be maintained. In addition, the water-discoloring image maintained the same shape as the water-discoloring image immediately after writing even when left for 30 minutes in an environment of 25°C and 65% RH. Furthermore, when the transparent template sheet was placed on the transparent cover member so that the water-discoloring image and the template overlapped, the portion where the black water-discoloring image and the red template of the transparent cover member overlapped was visually recognized as black, but the portion where the water-discoloring image did not overlap with the template was visually recognized as red. Therefore, it was possible to easily confirm whether the water-discoloring image was accurately formed as per the template. Next, when the transparent template sheet and the transparent cover member were removed from the water-discoloring sheet, the water-discoloring image gradually disappeared as the moisture evaporated, and at the stage when 10 minutes had passed, it completely decolorized and returned to the water-discoloring sheet with an all-white surface. This phenomenon could be repeated many times. Note that since the transparent cover member and the transparent template sheet had flexibility, the water-changing body could be rolled up and carried, and it had excellent portability.

[0021] Example 3 Production of water-changing body A water-discoloring sheet was obtained in the same manner as in Example 2. Next, convex portions made of white polyurethane resin with a hemispherical shape having a curved tip with a diameter of 3 mm and a height of 0.6 mm were provided at 48 locations in a grid pattern at an equal interval of 47 mm on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 253 mm × 353 mm as a transparent base material to obtain a transparent cover member. The surface area (s) of the convex portion visually recognized from the upper surface of the transparent cover member was 7.07 mm 2 and the height (h) of the convex portion was 0.5 mm, and the surface area (s) of the convex portion / the height (h) of the convex portion was 14.14. Also, the surface area of the upper surface of the transparent cover member is 893.09 cm 2 and the occupied area of the convex portions visually recognized from the upper surface of the transparent cover member is 3.39 cm 2 The ratio of the occupied area of the convex portions visually recognized from the upper surface of the transparent cover member to the surface area of the upper surface of the transparent cover member is 0.38%, and the number of convex portions per 100 cm 2 was 5.37 pieces. Furthermore, a transparent sample sheet was obtained by providing a sample of characters (Chinese characters 'kong') using a red printing ink having transparency on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 253 mm × 353 mm as the transparent base material. The light transmittance of the sample provided on the transparent sample sheet was 95%. A water-discoloring body including the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

[0022] The water-discoloring sheet normally exhibits white, but when writing on the porous layer with a writing brush whose brush tip is immersed in water, a black water-discoloring image (characters) can be formed. The water-discoloring image maintained the image for 5 minutes in an environment of 25°C and 65% RH, but gradually disappeared as the moisture evaporated, and returned to a completely white water-discoloring sheet after 10 minutes had elapsed. This phenomenon could be repeated many times. Next, the character 'kong' was written with a writing brush whose brush tip was immersed in water on the water-discoloring sheet to form a black water-discoloring image, and the transparent cover member was placed on the water-discoloring sheet on which the water-discoloring image was formed so that the tip of the convex portion contacted the surface of the water-discoloring sheet. The water-discoloring image could be clearly visually recognized through the transparent cover member, and the transparent cover member did not contact the water-discoloring image due to the convex portions, and a clear water-discoloring image could be maintained. Also, the water-discoloring image maintained the same shape as the water-discoloring image immediately after writing even when left for 30 minutes in an environment of 25°C and 65% RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the vermilion sample on the transparent sample sheet overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as vermilion. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon could be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0023] Example 4 Preparation of water-chromogenic materials A water-color-changing sheet was obtained in the same manner as in Example 2. Next, a transparent cover member was obtained by providing 48 convex portions made of white polyurethane resin, each with a diameter of 12 mm and a height of 5.0 mm, and a curved hemispherical shape, at equal intervals of 38 mm on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 262 mm x 362 mm, as a transparent substrate. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 113.04 mm². 2 The height (h) of the protrusion was 5.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 22.61. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 948.44 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 54.26 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 5.72%, and per 100 cm 2 The average number of protrusions per unit area was 5.06. Furthermore, a transparent template sheet was obtained by applying a transparent blue printing ink to the top surface of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 262 mm x 362 mm, using transparent blue printing ink to create a template of the character (the hiragana character "sora"). The light transmittance of the sample provided in the transparent cover member was 70%. A water-color-changing body was obtained comprising the water-color-changing sheet, the transparent cover member, and the transparent sample sheet.

[0024] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a brush dipped in water, it was possible to form a black water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the character "sora" was written on the water-color-changing sheet using a brush with a brush tip dipped in water to form a black water-color-changing image. The transparent cover member was then placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion was in contact with the surface of the water-color-changing sheet. The water-color change image could be clearly seen through the transparent cover member, and the protrusions prevented the transparent cover member from coming into contact with the water-color change image, thus maintaining a clear image. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 20 minutes in an environment of 25°C and 65%RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the blue sample on the transparent sample sheet overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as blue. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon could be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0025] Example 5 Preparation of water-chromogenic materials A water-color-changing sheet was obtained in the same manner as in Example 2. Next, a transparent cover member was obtained by providing 48 convex portions made of white polyurethane resin, each with a diameter of 15 mm and a height of 7.0 mm, in a grid pattern at equal intervals of 35 mm on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 265 mm x 365 mm, as a transparent substrate. These convex portions were made of white polyurethane resin and had a hemispherical shape with a curved tip, with a diameter of 15 mm and a height of 7.0 mm. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 176.63 mm². 2 The height (h) of the protrusion was 7.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 25.23. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 967.25 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 84.78 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 8.77%, and per 100 cm 2 The number of protrusions per unit area was 4.96. Furthermore, a transparent template sheet was obtained by applying a transparent green printing ink to the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 265 mm x 365 mm, thereby creating a template of characters (the katakana characters アイウエオ). The light transmittance of the sample provided in the transparent cover member was 50%. A water-color-changing body was obtained comprising the water-color-changing sheet, the transparent cover member, and the transparent sample sheet.

[0026] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a brush dipped in water, it was possible to form a black water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the characters "A, I, U, E, O" were written on the water-color-changing sheet using a brush with a brush tip dipped in water to form a black water-color-changing image. The transparent cover member was then placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion contacted the surface of the water-color-changing sheet. The water-color change image could be clearly seen through the transparent cover member, and the protrusions prevented the transparent cover member from coming into contact with the water-color change image, thus maintaining a clear image. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 15 minutes in an environment of 25°C and 65% RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the green sample on the transparent cover member overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as green. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon could be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0027] Example 6 Preparation of water-chromogenic materials A water-color-changing sheet was obtained in the same manner as in Example 2. Next, a transparent cover member was obtained by providing 48 convex portions made of white polyurethane resin, each with a diameter of 15 mm and a height of 10.0 mm, and a curved hemispherical shape, at equal intervals of 35 mm on the underside of a flexible polyester transparent sheet measuring 265 mm x 365 mm as a transparent substrate. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 176.63 mm². 2 The height (h) of the protrusion was 10.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 17.66. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 967.25 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 84.78 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 8.77%, and per 100 cm 2 The number of protrusions per unit area was 4.96. Furthermore, a transparent sample sheet was obtained by using a transparent vermilion printing ink to create a sample character (the kanji character for "land") on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 265 mm x 365 mm, which was used as a transparent substrate. The light transmittance of the sample placed on the aforementioned transparent sample sheet was 90%. A water-color-changing body was obtained comprising the water-color-changing sheet, the transparent cover member, and the transparent sample sheet.

[0028] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a brush dipped in water, it was possible to form a black water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the characters for "earth" were written on the water-color-changing sheet using a brush with a brush tip dipped in water to form a black water-color-changing image. The transparent cover member was then placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion was in contact with the surface of the water-color-changing sheet. The water-color change image could be clearly visualized through the transparent cover member, and the protrusions prevented the transparent cover member from coming into contact with the water-color change image, thus maintaining a clear image. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 10 minutes in an environment of 25°C and 65%RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the vermilion sample on the transparent cover member overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as vermilion. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon can be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0029] Example 7 Preparation of water-chromogenic materials A water-color-changing sheet was obtained in the same manner as in Example 2. Next, a transparent cover member was obtained by providing 48 convex portions made of white polyurethane resin, each with a diameter of 15 mm and a height of 0.5 mm, in a grid pattern at equal intervals of 35 mm on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 265 mm x 365 mm, as a transparent substrate. These convex portions were made of white polyurethane resin and had a hemispherical shape with a curved tip, with a diameter of 15 mm and a height of 0.5 mm. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 176.63 mm². 2 The height (h) of the protrusion was 0.5 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 353.33. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 967.25 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 84.78 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 8.77%, and per 100 cm 2 The number of protrusions per unit area was 4.96. Furthermore, a transparent sample sheet was obtained by using a transparent vermilion printing ink to create a sample character (the kanji character for "land") on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 265 mm x 365 mm, which was used as a transparent substrate. The light transmittance of the sample placed on the aforementioned transparent sample sheet was 90%. A transparent cover member and a transparent sample sheet were attached to one end of the aforementioned water-color-changing sheet, and the other end was left as a free end to obtain a water-color-changing body.

[0030] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a brush dipped in water, it was possible to form a black water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the characters for "earth" were written on the water-color-changing sheet using a brush with a brush tip dipped in water to form a black water-color-changing image. The transparent cover member was then placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion was in contact with the surface of the water-color-changing sheet. The water-color change image could be clearly visualized through the transparent cover member, and the protrusions prevented the transparent cover member from coming into contact with the water-color change image, thus maintaining a clear image. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 30 minutes in an environment of 25°C and 65%RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the vermilion sample on the transparent cover member overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as vermilion. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon can be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0031] Example 8 Preparation of water-chromogenic materials A water-color-changing sheet was obtained in the same manner as in Example 2. Next, a transparent cover member was obtained by providing 48 convex protrusions made of white, soft SEBS resin, with a diameter of 5 mm and a height of 10.0 mm, at equal intervals of 45 mm on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 255 mm x 355 mm, in a grid pattern. These protrusions were made at equal intervals of 45 mm. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 19.63 mm². 2 The height (h) of the protrusion was 10.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 1.96. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 905.25 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 9.42 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 1.04%, and per 100 cm 2 The number of protrusions per unit area was 5.30. Furthermore, a transparent sample sheet was obtained by using a transparent vermilion printing ink to create a sample character (the kanji character for "land") on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 265 mm x 365 mm, which was used as a transparent substrate. The light transmittance of the sample placed on the aforementioned transparent sample sheet was 90%. A transparent cover member and a transparent sample sheet were attached to one end of the aforementioned water-color-changing sheet, and the other end was left as a free end to obtain a water-color-changing body.

[0032] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a brush dipped in water, it was possible to form a black water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the characters for "earth" were written on the water-color-changing sheet using a brush with a brush tip dipped in water to form a black water-color-changing image. The transparent cover member was then placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion was in contact with the surface of the water-color-changing sheet. The water-color change image could be clearly visualized through the transparent cover member, and the protrusions prevented the transparent cover member from coming into contact with the water-color change image, thus maintaining a clear image. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 10 minutes in an environment of 25°C and 65%RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the vermilion sample on the transparent cover member overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as vermilion. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon can be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0033] Example 9 Weight: 130g / m 2On a support made of red polyester satin fabric, a porous layer was formed by uniformly mixing and stirring a white screen printing ink containing 15 parts of particulate silica produced by a wet process (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent, and then applying a solid print across the entire surface to form a water-color-changing sheet measuring 310 mm x 410 mm. Next, a transparent cover member was obtained by providing 63 convex portions made of transparent, soft PVC resin, with a thickness of 200 μm and dimensions of 310 mm x 410 mm, at 40 mm intervals on the underside of a transparent, flexible PVC sheet, with a diameter of 10 mm and a height of 3.0 mm, each convex to a hemispherical shape with a curved tip. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 78.5 mm². 2 The height (h) of the protrusion was 3.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 26.17. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 1271 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 49.46 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 3.9%, and per 100 cm 2 The number of protrusions per unit area was 4.95. Furthermore, a transparent sample sheet was obtained by applying a transparent green printing ink to the underside of a flexible polyester transparent sheet, 100 μm thick and measuring 300 mm x 400 mm, to create a sample of the character (the kanji character for "land"). The light transmittance of the sample provided in the transparent cover member was 80%. A transparent cover member and a transparent sample sheet were attached to one end of the aforementioned water-color-changing sheet, and the other end was left as a free end to obtain a water-color-changing body.

[0034] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a brush dipped in water, it was possible to form a red water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 3 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the characters for "earth" were written on the water-color-changing sheet using a brush tip containing water to form a water-color-changing image. The transparent cover member was then placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion contacted the surface of the water-color-changing sheet. The water-color change image could be clearly visualized through the transparent cover member, and the protrusions prevented the transparent cover member from coming into contact with the water-color change image, thus maintaining a clear image. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color-changing image and the sample overlap, the areas where the red water-color-changing image and the green sample on the transparent cover member overlap appear as a mixture of red and green, resulting in black, while the areas where they do not overlap appear as their respective colors. This makes it easy to confirm whether the water-color-changing image was formed accurately according to the sample. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 20 minutes in an environment of 25°C and 65%RH. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon can be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0035] Example 10 Preparation of water-chromogenic materials A water-color-changing sheet was obtained in the same manner as in Example 2. Next, on the lower surface of a flexible transparent polyester sheet with a thickness of 50 μm and a size of 253 mm × 353 mm as a transparent substrate, convex portions made of white polyurethane resin with a hemispherical shape having a curved tip with a diameter of 3 mm and a height of 0.4 mm were provided at 48 locations in a checkerboard pattern at an equal interval of 47 mm to obtain a transparent cover member. The surface area (s) of the convex portion visually recognized from the upper surface of the transparent cover member was 7.07 mm 2 The height (h) of the convex portion was 0.4 mm, and the surface area (s) of the convex portion / the height (h) of the convex portion was 17.68. Also, the surface area of the upper surface of the transparent cover member was 893.09 cm 2 The occupied area of the convex portion visually recognized from the upper surface of the transparent cover member was 3.39 cm 2 The occupied area ratio of the convex portion visually recognized from the upper surface of the transparent cover member to the surface area of the upper surface of the transparent cover member was 0.38%, and the number of convex portions per 100 cm 2 was 5.37. Furthermore, on the lower surface of a flexible transparent polyester sheet with a thickness of 50 μm and a size of 260 mm × 360 mm as a transparent substrate, a model of characters (Chinese characters 1, 2, 3) was provided using a transparent red printing ink to obtain a transparent model sheet. The light transmittance of the model provided on the transparent model sheet was 90%. The transparent cover member and the transparent model sheet were attached to one end portion of the water discoloring sheet, and the other end portion was set as a free end to obtain a water discoloring body.

[0036] The water discoloring sheet normally exhibited white, but when writing on the porous layer with a brush dipped in water at the tip, a black water discoloring image (characters) could be formed. The water discoloring image maintained the image for 5 minutes in an environment of 25 °C and 65% RH, but gradually disappeared as the moisture evaporated, and returned to a completely white water discoloring sheet after 10 minutes had elapsed. This phenomenon could be repeated many times. Next, the characters "one, two, three" were written with a writing brush dipped in water on the water-discoloring sheet to form a black water-discoloring image, and the transparent cover member was placed on the water-discoloring sheet on which the water-discoloring image was formed so that the tip of the convex portion contacted the surface of the water-discoloring sheet. The water-discoloring image could be clearly visually recognized through the transparent cover member. Also, although a part of the water-discoloring image contacted the transparent cover member and caused some bleeding, there was no problem in practical use, and a clear water-discoloring image could be maintained. In addition, the water-discoloring image maintained the same shape as the water-discoloring image immediately after writing even when left for 30 minutes in an environment of 25°C and 65% RH. Furthermore, when the transparent template sheet was placed on the transparent cover member so that the water-discoloring image and the template overlapped, the overlapping part of the black water-discoloring image and the vermilion template of the transparent cover member was visually recognized as black, but the part where the water-discoloring image did not overlap the template was visually recognized as vermilion. Therefore, it was possible to easily confirm whether the water-discoloring image was accurately formed as per the template. Next, when the transparent template sheet and the transparent cover member were removed from the water-discoloring sheet, the water-discoloring image gradually disappeared as the moisture evaporated, and at the stage when 10 minutes had passed, it completely decolorized and returned to the original water-discoloring sheet. This phenomenon could be repeated many times. Note that since the transparent template sheet and the transparent cover member had flexibility, the water-discoloring body could be rolled up and carried, and it had excellent portability.

[0037] Example 11 Production of water-discoloring body A water-discoloring sheet was obtained in the same manner as in Example 2. Next, convex portions made of white polyurethane resin in a conical shape with a curved tip having a diameter of 15 mm and a height of 12.0 mm were provided at 48 locations in a grid pattern at an equal interval of 35 mm on the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 265 mm × 365 mm as a transparent base material to obtain a transparent cover member. The surface area (s) of the convex portion visually recognized from the upper surface of the transparent cover member was 176.63 mm 2The height (h) of the protrusion was 12.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 14.72. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 967.25 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 84.78 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 8.77%, and per 100 cm 2 The number of protrusions per unit area was 4.96. Furthermore, a transparent template sheet was obtained by creating a template of characters (symbols such as ○△×) on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 265 mm × 365 mm, using transparent pink printing ink. The light transmittance of the sample placed on the aforementioned transparent sample sheet was 60%. A water-color-changing body was obtained comprising the aforementioned water-color-changing sheet, a transparent cover member, and a transparent sample sheet.

[0038] The aforementioned water-color-changing sheet is normally white, but when written on on the porous layer with a writing instrument equipped with a brush tip and containing water in the barrel, it was possible to form a black water-color-changing image (characters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the characters "〇△×" were written on the water-color-changing sheet using a brush with a brush tip dipped in water to form a black water-color-changing image. The transparent cover member was then placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion was in contact with the surface of the water-color-changing sheet. The water-color change image could be clearly visualized through the transparent cover member, and the transparent cover member did not come into contact with the water-color change image due to the protrusions, maintaining a clear water-color change image for 7 minutes in an environment of 25°C and 65% RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the pink sample on the transparent cover member overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as pink. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. The aforementioned water-induced discoloration gradually disappeared as the water evaporated, and after 15 minutes, the water-induced discoloration sheet returned to its completely white state. This phenomenon can be repeated many times. Furthermore, because the transparent sample sheet and transparent cover member are flexible, the water-color-changing body can be rolled up and carried, making it highly portable.

[0039] Reference example 1 (See Figure 5) Preparation of water-chromogenic materials A colored layer 4 was formed on a support 3 made of white synthetic paper by uniformly mixing and stirring a screen printing ink consisting of 5 parts blue pigment, 50 parts acrylic acid ester emulsion (50% by weight solids), 0.2 parts silicone-based defoaming agent, 3 parts thickener, 2 parts wetting agent, 1 part leveling agent, 10 parts water, and 2.5 parts epoxy crosslinking agent using a 180-mesh screen plate. Next, a porous layer 5 was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet process (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This mixture formed a solid print across the entire surface, resulting in a water-color-changing sheet measuring 220 mm x 320 mm. Next, as the transparent base material 7, a transparent cover member made of transparent hard ABS resin having a thickness of 1.0 mm, a size of 200 mm × 300 mm, with the peripheral portion of the lower surface in close contact with the surface of the water-discoloring sheet and having a 5-mm high void portion inside the peripheral portion to maintain a non-contact state with the surface of the water-discoloring sheet, and a pink-colored printed ink with transparency was used on the upper surface to provide a model 9 of a character (the Chinese character "mountain"). The light transmittance of the model 9 provided on the transparent cover member was 90%. A water-discoloring body provided with the water-discoloring sheet and the transparent cover member was obtained.

[0040] The water-discoloring sheet normally呈现 white, but has a fiber pen body at the tip, and when writing on the porous layer with a writing body containing water in the shaft cylinder, a blue water-discoloring image (character) can be formed. The water-discoloring image maintained the image for 5 minutes in an environment of 25°C and 65% RH. However, it gradually disappeared as the moisture evaporated, and at the stage when 10 minutes had passed, it returned to the completely white water-discoloring sheet. This phenomenon could be repeated many times. Next, the character "mountain" was written with a writing body containing water on the water-discoloring sheet to form a blue water-discoloring image, and the transparent cover member was placed on the water-discoloring sheet on which the water-discoloring image was formed. The water-discoloring image could maintain a clear water-discoloring image through the transparent cover member. Furthermore, when the transparent cover member was placed so that the water-discoloring image formed on the water-discoloring sheet overlapped with the model, the overlapping part of the blue water-discoloring image and the pink model of the transparent cover member was visually recognized as purple, a mixed color of blue and pink, and the non-overlapping parts were visually recognized as their respective colors. Therefore, it was possible to easily confirm whether the water-discoloring image was accurately formed as per the model. Also, the water-discoloring image maintained the same shape as the water-discoloring image immediately after writing even when left for 30 minutes in an environment of 25°C and 65% RH. Next, when the transparent cover member was removed from the water-discoloring sheet, the water-discoloring image gradually disappeared as the moisture evaporated, and at the stage when 10 minutes had passed, it completely decolorized and returned to the original water-discoloring sheet. This phenomenon could be repeated many times.

[0041] Reference example 2 (See Figure 6) Preparation of water-chromogenic materials A colored layer 4 was formed on a support 3 made of white synthetic paper by uniformly mixing and stirring a screen printing ink consisting of 5 parts blue pigment, 50 parts acrylic acid ester emulsion (50% by weight solids), 0.2 parts silicone-based defoaming agent, 3 parts thickener, 2 parts wetting agent, 1 part leveling agent, 10 parts water, and 2.5 parts epoxy crosslinking agent using a 180-mesh screen plate. Next, a porous layer 5 was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet process (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This mixture formed a solid print across the entire surface, resulting in a water-color-changing sheet measuring 220 mm x 320 mm. Furthermore, a transparent cover member was obtained made of transparent rigid ABS resin, with a thickness of 1.0 mm and dimensions of 200 mm x 300 mm, where the peripheral edge of the lower surface is in close contact with the surface of the water-color-changing sheet, and the inner part of the peripheral edge has a 10 mm high void that maintains a non-contact state with the surface of the water-color-changing sheet. Furthermore, a transparent sample sheet was obtained by applying a transparent yellow printing ink to the underside of a flexible polyester transparent sheet, 50 μm thick and measuring 200 mm x 300 mm, as the transparent substrate 71, thereby creating a sample sheet of letters (numbers 1, 2, 3, 4, 5). The light transmittance of sample 9 provided on the transparent sample sheet was 98%. A water-color-changing body was obtained comprising the water-color-changing sheet, the transparent cover member, and the transparent sample sheet.

[0042] The aforementioned water-color-changing sheet is normally white, but when written on on the porous layer with a writing instrument having a fibrous pen tip and containing water in the barrel, it was possible to form a blue water-color-changing image (letters). The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, the letters "12345" were written on the water-color-changing sheet using a cursive writing tool containing water to form a blue water-color-changing image, and a transparent cover member was placed on the water-color-changing sheet on which the water-color-changing image was formed. The aforementioned water-color change image was able to maintain a clear image through the transparent cover member. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color-changing image and the sample overlap, the overlapping areas of the blue water-color-changing image and the yellow sample on the transparent sample sheet appear as a mixture of blue and yellow, resulting in a green color, while the areas that do not overlap appear as their respective colors. This makes it easy to confirm whether the water-color-changing image was formed accurately according to the sample. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 30 minutes in an environment of 25°C and 65%RH. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing image gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon could be repeated many times.

[0043] Example 14 Preparation of a water-chromogenic organism set (see Figure 7) A water-color-changing body set 12 was obtained by combining the water-color-changing body 1 from Example 1 with a water-attaching device 11 (a writing instrument containing water). The aforementioned water-color-changing body set allows for the formation of a water-color-changing image on a water-color-changing sheet using a water-adhering tool. Similar to Example 1, by placing a transparent cover member on top, the water-color-changing image can be clearly seen through the transparent cover member. The protrusions prevent the transparent cover member from coming into contact with the water-color-changing image, allowing for the maintenance of a clear water-color-changing image for an extended period. Furthermore, since a template is provided on the transparent cover component, it was possible to visually confirm whether the water-color change image was formed according to the template, and to verify whether the water-color change image was formed accurately and in a balanced manner. Furthermore, each of the water-color-changing materials from Examples 2 to 11 was combined with a water-adhering device (a writing instrument containing water) to obtain a water-color-changing material set. The aforementioned water-color-changing body set allows for the formation of a water-color-changing image on a water-color-changing sheet using a water-adhering tool. By placing a transparent cover member on top, similar to Examples 2 to 11, the water-color-changing image can be clearly seen through the transparent cover member. The protrusions prevent the transparent cover member from coming into contact with the water-color-changing image, allowing for the maintenance of a clear water-color-changing image for an extended period. Furthermore, by placing the transparent sample sheet on the transparent cover member, it was possible to visually confirm whether the water-color change image was formed according to the sample, since the transparent cover member has a sample sheet on it, and to verify whether the water-color change image was formed accurately and in a balanced manner. Furthermore, a water-color-changing body set was obtained by combining the water-color-changing body from Example 12 with a water-adhering device (a writing instrument containing water). The aforementioned water-color-changing body set allows for the formation of a water-color-changing image on a water-color-changing sheet using a water-adhering tool. By placing a transparent cover member on top, similar to Example 12, the water-color-changing image can be clearly seen through the transparent cover member. The transparent cover member does not come into contact with the water-color-changing image due to voids, and a clear water-color-changing image can be maintained for a long period of time. Furthermore, since a template is provided on the transparent cover component, it was possible to visually confirm whether the water-color change image was formed according to the template, and to verify whether the water-color change image was formed accurately and in a balanced manner. Furthermore, a water-color-changing body set was obtained by combining the water-color-changing body from Example 13 with a water-adhering device (a writing instrument containing water). The aforementioned water-color-changing body set allows for the formation of a water-color-changing image on a water-color-changing sheet using a water-adhering tool. By placing a transparent cover member on top, similar to Example 13, the water-color-changing image can be clearly seen through the transparent cover member. The transparent cover member does not come into contact with the water-color-changing image due to the voids, and a clear water-color-changing image can be maintained for a long period of time. Furthermore, by placing the transparent sample sheet on the transparent cover member, it was possible to visually confirm whether the water-color change image was formed according to the sample, since the transparent cover member has a sample sheet on it, and to verify whether the water-color change image was formed accurately and in a balanced manner.

[0044] Example 15 Preparation of water-chromogenic materials A colored layer was formed by screen printing using a 180-mesh screen plate with a screen printing ink prepared by uniformly mixing and stirring 5 parts blue pigment, 50 parts acrylic ester emulsion (50% solids by weight), 0.2 parts silicone-based defoamer, 3 parts thickener, 2 parts wetting agent, 1 part leveling agent, 10 parts water, and 2.5 parts epoxy crosslinking agent on a support made of white synthetic paper. Next, a porous layer was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet process (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This mixture formed a solid print across the entire surface, resulting in a water-color-changing sheet measuring 220 mm x 320 mm. Next, on the lower surface of a plate-shaped molded article made of a transparent hard acrylonitrile resin with a thickness of 1.0 mm, a size of 200 mm × 300 mm, and a non-glossy upper surface having fine irregularities, three convex portions made of a transparent ABS resin in the shape of a cone with a curved tip having a diameter of 10 mm and a height of 1.0 mm were provided at positions corresponding to the vertices of an isosceles triangle. A template of a character (the Chinese character "mountain") was provided on the upper surface of the plate-shaped molded article using a transparent red printing ink to obtain a transparent cover member 6. The light transmittance of the template provided on the transparent cover member was 80%. The surface area (s) of the convex portion visually recognized from the upper surface of the transparent cover member was 78.5 mm 2 The height (h) of the convex portion was 1.0 mm, and the surface area (s) of the convex portion / the height (h) of the convex portion was 78.5. Also, the surface area of the upper surface of the transparent cover member was 600 cm 2 The occupied area of the convex portion visually recognized from the upper surface of the transparent cover member was 2.36 cm 2 The ratio of the occupied area of the convex portion visually recognized from the upper surface of the transparent cover member to the surface area of the upper surface of the transparent cover member was 0.39%. A water discoloration body provided with the water discoloration sheet and the transparent cover member was obtained.

[0045] The water discoloration sheet normally呈现白色, but has a fiber pen body at the tip. When writing on the porous layer with a writing body containing water in the shaft cylinder, a blue water discoloration image (character) can be formed. The water discoloration image maintained the image for 5 minutes in an environment of 25°C and 65% RH. However, it gradually disappeared with the evaporation of moisture and returned to a completely white water discoloration sheet after 10 minutes. This phenomenon could be repeated many times. Next, the character "mountain" was written with a writing body containing water on the water discoloration sheet to form a blue water discoloration image. The transparent cover member was placed on the water discoloration sheet on which the water discoloration image was formed so that the tip of the convex portion contacted the surface of the water discoloration sheet. The water-color-changing image could be seen even more clearly through the transparent cover member without light reflecting off the surface of the transparent cover member and hindering visibility. Furthermore, the protrusions prevented the transparent cover member from coming into contact with the water-color-changing image, thus maintaining a clear water-color-changing image. Furthermore, when photographs were taken indoors with the transparent cover component in place, there was no reflection of the lighting fixtures, and a clear image of the water discoloration was captured. Furthermore, when a transparent cover is placed so that the water-color-changing image formed on the water-color-changing sheet overlaps with the model, the areas where the blue water-color-changing image and the red model on the transparent cover overlap appear as a mixture of red and blue, resulting in purple, while the areas where they do not overlap appear as their respective colors. This makes it easy to confirm whether the water-color-changing image was formed accurately according to the model. Furthermore, the water-color change image maintained the same shape as the image immediately after writing, even after being left for 30 minutes in an environment of 25°C and 65%RH. Next, when the transparent cover material was removed from the water-color-changing sheet, the water-color-changing pattern gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to its original state as a water-color-changing sheet. This phenomenon could be repeated many times. Furthermore, by combining the water-color-changing material with an erasable writing instrument (whiteboard marker), it was possible to write on the surface of the transparent cover member using the whiteboard marker to point out areas of weakness in the water-color-changing image and score them. In addition, the marker marks could be easily removed by rubbing the surface of the transparent cover member with a dry cloth or whiteboard eraser.

[0046] Example 16 Preparation of water-chromogenic materials A colored layer was formed by screen printing using a 180-mesh screen plate with a screen printing ink prepared by uniformly mixing and stirring 5 parts blue pigment, 50 parts acrylic ester emulsion (50% solids by weight), 0.2 parts silicone-based defoamer, 3 parts thickener, 2 parts wetting agent, 1 part leveling agent, 10 parts water, and 2.5 parts epoxy crosslinking agent on a support made of white synthetic paper. Next, a porous layer was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet process (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This mixture formed a solid color layer, and three water-color-changing sheets measuring 220 mm x 320 mm were obtained. Next, a transparent hard ABS resin plate molded as a transparent base material, 1.0 mm thick and measuring 200 mm x 300 mm in size, was prepared. Three cone-shaped protrusions made of transparent ABS resin, each 10 mm in diameter and 1.0 mm high with a curved tip, were placed on the lower surface at positions corresponding to the vertices of an isosceles triangle. A model of the character (the kanji for "mountain") was then printed on the upper surface of the plate molded material using transparent red printing ink to obtain two transparent cover members. The light transmittance of the sample provided in the transparent cover member was 80%. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 78.5 mm². 2 The height (h) of the protrusion was 1.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 78.5. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 600 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 2.36 cm². 2 The ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member was 0.39%. A water-color-changing body was obtained, comprising the three water-color-changing sheets and the two transparent cover members.

[0047] The water-discoloring sheet normally exhibits a white color, but has a fiber pen body at its tip. When writing on a porous layer with a writing body containing water in a shaft cylinder, a blue water-discoloring image (characters) can be formed. The water-discoloring image maintained the image for 5 minutes in an environment of 25°C and 65% RH. However, it gradually disappeared with the evaporation of moisture and returned to the completely white water-discoloring sheet after 10 minutes. This phenomenon could be repeated many times. Next, with the writing body containing water on the water-discoloring sheet, the character "mountain" was written to form a blue water-discoloring image, and the transparent cover member was placed on the water-discoloring sheet on which the water-discoloring image was formed so that the tip of the convex portion contacted the surface of the water-discoloring sheet. The water-discoloring image could be clearly visually recognized through the transparent cover member, and the convex portion enabled the transparent cover member to maintain a clear water-discoloring image without contacting the water-discoloring image. Furthermore, when the transparent cover member was placed so that the water-discoloring image formed on the water-discoloring sheet overlapped with the template, the overlapping portion of the blue water-discoloring image and the red template of the transparent cover member was visually recognized as purple, which is a mixed color of red and blue, and the non-overlapping portions were visually recognized as their respective colors, so it was possible to easily confirm whether the water-discoloring image was accurately formed as per the template. Also, the water-discoloring image maintained the same shape as the water-discoloring image immediately after writing even when left for 30 minutes in an environment of 25°C and 65% RH. Next, when the transparent cover member was removed from the water-discoloring sheet, the water-discoloring image gradually disappeared with the evaporation of moisture and completely faded to return to the original water-discoloring sheet after 10 minutes. This phenomenon could be repeated many times. Also, after removing the transparent cover member from the water-discoloring sheet, before completely fading and returning to the original water-discoloring sheet, a water-discoloring image was formed on another water-discoloring sheet and the transparent cover member was placed, enabling the image to be formed quickly.

[0048] Example 17 Production of the water-discoloring body A colored layer was formed by screen printing using a 180-mesh screen plate with a screen printing ink prepared by uniformly mixing and stirring 5 parts black pigment, 50 parts acrylic ester emulsion (50% solids by weight), 0.2 parts silicone-based defoamer, 3 parts thickener, 2 parts wetting agent, 1 part leveling agent, 10 parts water, and 2.5 parts epoxy crosslinking agent on a support made of polyester nonwoven fabric on white synthetic paper. Next, a porous layer was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet process (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This white screen printing ink was then applied to the entire surface to form a porous layer, resulting in a water-color-changing sheet measuring 280 mm x 380 mm. Next, a transparent cover member was obtained by providing 48 convex portions made of white polyurethane resin, each with a diameter of 3 mm and a height of 1.2 mm, and a curved hemispherical shape, at equal intervals of 47 mm on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 253 mm x 353 mm, as a transparent substrate, in a grid pattern at the bottom surface. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 7.07 mm². 2 The height (h) of the protrusion was 1.2 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 5.89. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 893.09 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 3.39 cm². 2 Therefore, the ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member is 0.38%, and per 100 cm 2 The number of protrusions per unit area was 5.37. Furthermore, on the lower surface of a transparent polyester sheet with a thickness of 50 μm, a size of 233 mm × 333 mm, having fine irregularities on the upper surface, being non-glossy and flexible, a sample of characters (Chinese characters "山川") was provided using a transparent red printing ink to obtain a transparent sample sheet. The light transmittance of the sample provided on the transparent sample sheet was 90%. A water-discoloring body provided with the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

[0049] The water-discoloring sheet normally呈现白色, but when writing on the porous layer with a brush whose brush tip was dipped in water, a black water-discoloring image (characters) could be formed. The water-discoloring image maintained the image for 5 minutes in an environment of 25°C and 65% RH, but gradually disappeared as the moisture evaporated, and returned to a completely white water-discoloring sheet after 10 minutes had passed. This phenomenon could be repeated many times. Next, the characters "山川" were written with a brush whose brush tip was dipped in water on the water-discoloring sheet to form a black water-discoloring image, and the transparent cover member was placed on the water-discoloring sheet on which the water-discoloring image was formed so that the tip of the convex portion contacted the surface of the water-discoloring sheet. The water-discoloring image could be clearly visually recognized through the transparent cover member, and the convex portion enabled the transparent cover member not to contact the water-discoloring image, and a clear water-discoloring image could be maintained. Also, the water-discoloring image maintained the same shape as the water-discoloring image immediately after writing even when left for 30 minutes in an environment of 25°C and 65% RH. Furthermore, when the transparent sample sheet was placed on the transparent cover member so that the water-discoloring image and the sample overlapped, the water-discoloring image could be more clearly visually recognized through the transparent sample sheet without the light reflected on the surface of the transparent sample sheet disturbing the visibility. Also, the overlapping portion of the black water-discoloring image and the red sample of the transparent cover member was visually recognized as black, but the portion where the water-discoloring image did not overlap with the sample was visually recognized as red. Therefore, it was possible to easily confirm whether the water-discoloring image was accurately formed as per the sample. Furthermore, when we took photographs with a transparent sample sheet placed indoors, there was no reflection of the lighting fixtures, and we were able to capture clear images of water discoloration. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing pattern gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to being a water-color-changing sheet that was entirely white. This phenomenon could be repeated many times. Furthermore, because the transparent cover member and the transparent sample sheet are flexible, the water-color-changing material can be rolled up and carried, making it highly portable.

[0050] Example 18 Preparation of water-chromogenic materials A colored layer was formed by screen printing using a 180-mesh screen plate with a screen printing ink prepared by uniformly mixing and stirring 5 parts black pigment, 50 parts acrylic ester emulsion (50% solids by weight), 0.2 parts silicone-based defoamer, 3 parts thickener, 2 parts wetting agent, 1 part leveling agent, 10 parts water, and 2.5 parts epoxy crosslinking agent on a support made of polyester nonwoven fabric on white synthetic paper. Next, a porous layer was formed by uniformly mixing and stirring a white screen printing ink on the colored layer, which consisted of 15 parts of fine particulate silica produced by a wet method (product name: NipSeal E-200A, manufactured by Nippon Silica Industry Co., Ltd.), 50 parts of water-based urethane resin as a binder resin (product name: Hydran AP-10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of water, 0.5 parts of silicone-based defoaming agent, 3 parts of water-based ink thickener, 1 part of ethylene glycol, and 2 parts of epoxy-based crosslinking agent. This mixture formed a solid color layer, and three water-color-changing sheets measuring 280 mm x 380 mm were obtained. Next, a transparent cover member (2 pieces) was obtained by providing 48 convex protrusions made of white polyurethane resin, with a diameter of 3 mm and a height of 1.2 mm, and a curved tip, at equal intervals of 47 mm on the underside of a flexible polyester transparent sheet with a thickness of 50 μm and dimensions of 253 mm x 353 mm, in a grid pattern. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 7.07 mm².2 where the height (h) of the convex portion was 1.2 mm, and the surface area (s) of the convex portion divided by the height (h) of the convex portion was 5.89. Also, the surface area of the upper surface of the transparent cover member was 893.09 cm 2 and the occupied area of the convex portion visible from the upper surface of the transparent cover member was 3.39 cm 2 The ratio of the occupied area of the convex portion visible from the upper surface of the transparent cover member to the surface area of the upper surface of the transparent cover member was 0.38%, and the number of convex portions per 100 cm 2 was 5.37. Furthermore, a sample of characters (Chinese characters "Shanchuan") was provided by using a transparent red printing ink on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 233 mm × 333 mm as the transparent base material to obtain two transparent sample sheets. The light transmittance of the sample provided on the transparent sample sheet was 90%. A water discoloration body was obtained, which included three water discoloration sheets, two transparent cover members, and two transparent sample sheets.

[0051] The water discoloration sheet normally呈现白色, but when writing on the porous layer with a brush dipped in water on the brush tip, a black water discoloration image (characters) could be formed. The water discoloration image maintained the image for 5 minutes in an environment of 25°C and 65% RH, but gradually disappeared as the moisture evaporated, and returned to a completely white water discoloration sheet after 10 minutes. This phenomenon could be repeated many times. Next, the characters "Shanchuan" were written with a brush dipped in water on the brush tip on the water discoloration sheet to form a black water discoloration image, and the transparent cover member was placed on the water discoloration sheet on which the water discoloration image was formed so that the tip of the convex portion contacted the surface of the water discoloration sheet. The water discoloration image could be clearly visually recognized through the transparent cover member, and the transparent cover member did not contact the water discoloration image due to the convex portion, and a clear water discoloration image could be maintained. Also, the water discoloration image maintained the same shape as the water discoloration image immediately after writing even when left for 30 minutes in an environment of 25°C and 65% RH. Furthermore, when a transparent sample sheet is placed on top of the transparent cover member so that the water-color change image and the sample overlap, the areas where the black water-color change image and the vermilion sample on the transparent cover member overlap appear as black, while the areas where the water-color change image does not overlap with the sample appear as vermilion. This makes it easy to confirm whether the water-color change image was formed accurately according to the sample. Next, when the transparent sample sheet and transparent cover member were removed from the water-color-changing sheet, the water-color-changing pattern gradually disappeared as the water evaporated, and after 10 minutes, it was completely discolored and returned to being a water-color-changing sheet that was entirely white. This phenomenon could be repeated many times. Furthermore, because the transparent cover member and the transparent sample sheet are flexible, the water-color-changing material can be rolled up and carried, making it highly portable. Furthermore, after removing the transparent cover member and transparent sample sheet from the water-color-changing sheet, and before completely decolorizing and returning to the original water-color-changing sheet, a water-color-changing image was formed on another water-color-changing sheet, and the transparent cover member and transparent sample sheet were placed on top of it, allowing for rapid image formation.

[0052] Comparative Example 1 Preparation of water-chromogenic materials Water-changed in the same manner as in Example 1 Color I obtained the ticket. Next, a transparent cover member was obtained by providing two cone-shaped protrusions made of transparent ABS resin with a diameter of 10 mm and a height of 1.0 mm, and a curved tip, on the lower surface of a plate-shaped molded object made of transparent rigid ABS resin, with a thickness of 1.0 mm and a size of 200 mm x 300 mm, as a transparent base material. The surface area (s) of the protrusion visible from the upper surface of the transparent cover member is 78.5 mm². 2 The height (h) of the protrusion was 1.0 mm, and the ratio of the surface area (s) of the protrusion to the height (h) was 78.5. Furthermore, the surface area of ​​the upper surface of the transparent cover member is 600 cm². 2 Therefore, the area occupied by the protrusion visible from the top surface of the transparent cover member is 2.36 cm². 2The ratio of the area occupied by the protrusions visible from the top surface of the transparent cover member to the surface area of ​​the top surface of the transparent cover member was 0.39%. A water-color-changing body was obtained, comprising the water-color-changing sheet and the transparent cover member.

[0053] The aforementioned water-color-changing sheet is normally white, but when written on the porous layer with a water-containing writing instrument, it was able to form a blue water-color-changing image. The aforementioned water-induced color change pattern remained visible for 5 minutes under conditions of 25°C and 65% RH. However, it gradually disappeared as the water evaporated, and after 10 minutes, the water-induced color change sheet returned to a completely white state. This phenomenon could be repeated multiple times. Next, a water-color-changing image was formed by writing on the water-color-changing sheet with a writing instrument containing water, and the transparent cover member was placed on the water-color-changing sheet on which the water-color-changing image was formed, such that the tip of the protrusion contacted the surface of the water-color-changing sheet. Although the water-color change image could be viewed through the transparent cover member, contact occurred between the transparent cover member and the water-color change image, causing blurring of the image. Furthermore, when the water-color-changing image is left in an environment of 25°C and 65% RH, differences occur in the distance between the transparent cover member and the water-color-changing image. As a result, differences occur in the decolorization time of the water-color-changing image, making it impossible to maintain a uniform water-color-changing image. [Explanation of symbols]

[0054] 1. Water-chromogenic organism 2. Water-color-changing sheet 3 Support 4 Colored layer 5. Porous layer 6. Transparent cover component 7,71 Transparent substrate 8. Convex part 9. Examples 10 Transparency Model Sheets 11 Cavity 12 Water adhesion tool 13 Water-Color-Changing Body Set

Claims

1. The device comprises a water-color-changing sheet having a porous layer on top of a colored layer in which a low refractive index pigment is dispersed and fixed in a binder resin, and a transparent cover member that covers the water-color-changing image formed by the adhesion of water to the surface of the porous layer, suppresses the drying of the water, and delays the disappearance of the water-color-changing image. The lower surface of the transparent cover member has at least three non-linearly arranged point-like protrusions that maintain a non-contact state between the surface of the water-color-changing sheet and the transparent cover member, and the protrusions have a height of 0.4 mm to 12.0 mm, and the surface area s (mm²) of the protrusions visible from the upper surface of the transparent cover member is 2 ) and the height h (mm) of the protrusions satisfy the following formula (1), the area occupied by the protrusions visible from the top surface of the transparent cover member is 10% or less of the surface area of ​​the top surface of the transparent cover member, the transparent cover member is provided with a model of characters to be formed on the water-color change sheet, and the porous layer is a water-color change body in which the color in the dry state, the color of the water-color change image, and the color of the model are all different. 1.0 ≤ s / h ≤ 400 (1)

2. The device comprises a water-color-changing sheet having a porous layer on top of a colored layer in which a low refractive index pigment is dispersed and fixed in a binder resin; a transparent cover member that covers the water-color-changing image formed by the adhesion of water to the surface of the porous layer, suppresses the drying of the water, and delays the disappearance of the water-color-changing image; and a transparent guide sheet having a model of the characters to be formed on the water-color-changing sheet. The lower surface of the transparent cover member has at least three non-linearly arranged point-like protrusions that maintain a non-contact state between the surface of the water-color-changing sheet and the transparent cover member, and the protrusions have a height of 0.4 mm to 12.0 mm, and the surface area s (mm²) of the protrusions visible from the upper surface of the transparent cover member is 2 ) and the height h (mm) of the protrusions satisfy the following formula (1), the area occupied by the protrusions visible from the top surface of the transparent cover member is 10% or less of the surface area of ​​the top surface of the transparent cover member, and the porous layer is a water-color-changing body in which the color of the dry state, the color of the water-color-changed image, and the color of the model are all different. 1.0 ≤ s / h ≤ 400 (1)

3. The water-color-changing body according to claim 1 or 2, wherein the convex portion is transparent.

4. The water-color-changing body according to claim 1 or 2, wherein the convex portion exhibits a white color.

5. The water-color-changing body according to any one of claims 1 to 4, wherein the tip of the protrusion has a curved shape.

6. The water-color-changing body according to any one of claims 1 to 5, wherein the transparent cover member is flexible and the protrusions are three or more per 100 cm².

7. The water-color-changing body according to any one of claims 1 to 6, wherein the surface of the transparent cover member is non-glossy.

8. The water-color changer according to claim 2, wherein the surface of the transparent sample sheet is non-glossy.

9. The water-color-changing body according to any one of claims 1 to 8, wherein the transparent cover member is attached to the water-color-changing sheet at one end and the other end is a free end, and is provided on the water-color-changing sheet so as to be openable and closable.

10. A water-color changing body according to any one of claims 1 to 8, comprising a plurality of water-color changing sheets and a plurality of transparent cover members.

11. The water-color change body according to claim 2, comprising a plurality of the water-color change sheets, a plurality of the transparent cover members, and a plurality of the transparent sample sheets.

12. The water-color changer according to any one of claims 1 to 11, wherein the light transmittance of the model is 20 to 99%.

13. The water-color-changing body according to claim 1 or 2, wherein the dot-shaped protrusions are arranged in a grid pattern.

14. A water-color changing body set comprising a water-color changing body according to any one of claims 1 to 13 and a water-adhering device for forming a water-color changing image.

Images