JP2022169437A - Water discoloration body, and water discoloration body set - Google Patents

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

The present invention relates to a water-color body and a water-color body set. More particularly, the present invention relates to a water-discoloring body and a water-discoloring body set comprising a water-discoloring sheet and a cover member for delaying disappearance of a water-discoloring image formed on the water-discoloring sheet.

Conventionally, there has been disclosed a water discoloration body in which a porous layer in which a low refractive index pigment that is opaque in a non-water-absorbing state and becomes transparent in a water-absorbing state is fixed to a binder resin in a dispersed state is arranged on a colored layer. Alternatively, a water-discoloring material set is disclosed that extends the maintenance time of the water-discoloring image by covering the water-discoloring image with a cover member immediately after forming the water-discoloring image by attaching water using a stamp tool, fingers, or the like. (See Patent Document 1, for example).
The water-discoloring material set can extend the water-discoloring image retention time, and can satisfy the practicality of toys and teaching tools.

JP-A-2002-254547

The present invention provides a water-discoloring body and a water-discoloring body set that can extend the maintenance time of the water-discoloring image formed on this type of water-discoloring material and can confirm whether the water-discoloring image is formed in a well-balanced manner. I am trying to.

The present invention provides a water-discoloring sheet having a porous layer in which a low refractive index pigment is fixed in a dispersed state in a binder resin as an upper layer of a colored layer, and a water-discoloring sheet formed by adhesion of water to the surface of the porous layer. a transparent cover member that covers the image, suppresses drying of water, and delays disappearance of the water-discolored image, and the transparent cover member is provided with a model of characters to be formed on the water-discolored sheet. or a water-discoloring sheet having a porous layer in which a low refractive index pigment is fixed in a dispersed state to a binder resin as an upper layer of a colored layer, and a water-discoloring sheet formed by attaching water to the surface of the porous layer. a transparent cover member for covering the water-discolored image formed thereon, suppressing drying of the water, and delaying disappearance of the water-discolored image; A water discoloration body consisting of a sheet is required.
Further, the surface of the water-discoloring sheet and the transparent cover member are held in a non-contact state on the lower surface of the transparent cover member, and at least three or more protrusions in contact with the surface of the water-discoloring sheet are arranged non-linearly. The convex portion has a height of 0.4 mm to 12.0 mm, and the surface area (s) of the convex portion visible from the upper surface of the transparent cover member and the height (h) of the convex portion are as follows: satisfying formula (1);
1.0≤s/h≤500 (1)
The occupied area of the protrusions visible from the upper surface of the transparent cover member is 20% or less of the surface area of the upper surface of the transparent cover member, the protrusions are transparent, and the protrusions are white. the tip of the convex portion is curved; the transparent cover member is flexible; and the transparent cover member has three or more convex portions per 100 cm ² ; The surface of the transparent sample sheet is non-glossy, and the transparent cover member has a peripheral portion of the lower surface that is in close contact with the surface of the water-discolored sheet, and an inner portion of the peripheral portion that is non-contact with the surface of the water-discolored sheet. The transparent cover member has one end attached to the water-discoloring sheet and the other end serving as a free end, and is provided so as to be openable and closable on the water-discoloring sheet. , comprising a plurality of the water-discoloring sheets and a plurality of the transparent cover members, and comprising a plurality of the water-discoloring sheets, a plurality of the transparent cover members, and a plurality of the transparent sample sheets , the light transmittance of the sample is 20 to 99%, and the color of the porous layer in the dry state, the color of the water discolored image, and the color of the sample are different.
Furthermore, a water-discoloring body set including the water-discoloring body and a water adhesion tool for forming a water-discoloring image is required.

The present invention easily extends the maintenance time of the water-discolored image by covering the water-discolored image with a cover member immediately after forming the water-discolored image by attaching water with a writing or stamp tool, fingers, or the like. It is possible to provide a water-discoloring body and a water-discoloring body set which satisfy marketability and practicality as a toy and a training tool which can be confirmed whether or not a water-discoloring image is formed in a well-balanced manner.

1 is a top view showing a water-discoloring body of one embodiment of the present invention; FIG. FIG. 2 is a side view of the water discoloration body of FIG. 1; FIG. 4 is a top view showing a water-discoloring body of another embodiment of the present invention; 4 is a side view of the water discoloration body of FIG. 3; FIG. FIG. 3 is a side view showing a water-discoloring body of another embodiment of the present invention; FIG. 3 is a side view showing a water-discoloring body of another embodiment of the present invention; 1 is a top view of a water-discoloring body set according to an embodiment of the present invention; FIG.

The water discoloration sheet comprises a porous layer in which a low refractive index pigment is fixed in a binder resin in a dispersed state on the upper layer of the colored layer.
As for the colored layer, the support itself may serve as a colored layer, but it is preferable to provide a colored layer (including an image of arbitrary shape) on the surface of the support.
As the support, paper, synthetic paper, fabrics such as woven fabrics, knitted fabrics, braided fabrics and non-woven fabrics, natural or synthetic leathers, plastics, glass, ceramics, metals, woods, stones, and the like are used. As for the shape, a planar shape is preferable, but an uneven shape may be used.
The colored layer provided on the surface of the support is formed of a binder resin containing a coloring agent.
Examples of the coloring agent include general dyes, general pigments, fluorescent dyes, fluorescent pigments, metallic luster pigments, and the like.
The 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 volatile matter 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, and 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 the above Resin emulsions, casein, starch, cellulose derivatives, polyvinyl alcohol, urea resins, phenol resins and the like can be used.
The colored layer may be processed printing, screen printing, offset printing, gravure printing, coater, tampo printing, inkjet printing, printing means such as transfer, brush coating, spray coating, electrostatic coating, electrodeposition coating, flow coating, roller coating. , dip coating or the like on the substrate.
In addition, a transfer layer is provided by applying ink or paint contained in a vehicle containing a colorant and a binder resin as a binder on another substrate in advance, and the transfer layer is transferred onto a support to form a colored layer. can also be set.
Furthermore, when the support has transparency, a colored layer can be provided on the back surface of the support (the surface on which the porous layer is not provided).

A water discoloring sheet can be obtained by laminating a porous layer in which a low refractive index pigment is fixed in a dispersed state with a binder resin on the colored layer.
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 the layer has different transparency in a dry state and a liquid absorption state.
Examples of the low refractive index pigment include silicic acid and its salts, barite powder, barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, talc, alumina white, magnesium carbonate, etc., which have a refractive index of 1.4 to It is in the range of 1.8 and exhibits good transparency when water is absorbed.
Examples of the silicic acid salt include aluminum silicate, potassium aluminum silicate, sodium aluminum silicate, calcium aluminum silicate, potassium silicate, calcium silicate, sodium calcium silicate, sodium silicate, magnesium silicate, and potassium magnesium silicate.
In addition, silicic acid is mentioned as a low-refractive-index pigment suitably used.
Also, two or more of the low refractive index pigments can be used in combination.
Although the particle size of the low refractive index pigment is not particularly limited, those having a particle size of 0.03 to 10.0 μm are preferably used.
The silicic acid may be silicic acid produced by a dry method, but silicic acid produced by a wet method (hereinafter referred to as wet silicic acid) is particularly effective. Amorphous silicic acid produced as pure amorphous silicic acid by a dry method using a vapor phase reaction such as thermal decomposition of silicon halide such as silicon tetrachloride (hereinafter referred to as dry method silicic acid) and sodium silicate Wet process silicic acid and wet process silicic acid have different structures, and dry process silicic acid has a three-dimensional structure in which silicic acid is tightly bound. In contrast, wet-process silicic acid has a so-called two-dimensional structural portion in which silicic acid has condensed to form a long molecular arrangement.
Therefore, since the molecular structure is coarser than that of the dry-process silicic acid, when the wet-process silicic acid is applied to the porous layer, the diffuse reflection of light in a dry state is superior to the system using the dry-process silicic acid. It is presumed that the concealability in the normal state is increased.
In addition, since the porous layer absorbs water, wet-process silicic acid has more hydroxyl groups present as silanol groups on the particle surface than dry-process silicic acid, and has a high degree of hydrophilicity, which is preferable. used for
In addition, other low refractive index pigments may be used in combination with the wet-process silicic acid in order to adjust the hiding property of the porous layer in the normal state and the transparency in the liquid-absorbing state.

The low refractive index pigment in the porous layer depends on properties such as particle size, specific surface area, and oil absorption. The coating amount is preferably 1-50 g/m ² , more preferably 5-50 g/m ² . If it is less than 1 g/m ² , it is difficult to obtain sufficient hiding power under normal conditions, and if it exceeds 50 g/m ² , it is difficult to obtain sufficient transparency when liquid is absorbed.
The low refractive index pigment is dispersed in a vehicle containing a binder resin as a binder, coated on a support, and then dried to remove volatiles 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, and 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 the above Resin emulsions, casein, starch, cellulose derivatives, polyvinyl alcohol, urea resins, phenol resins and the like can be used.
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. parts, more preferably 0.8 to 1.5 parts by mass. If the binder resin solid content is less than 0.5 parts by mass with respect to 1 part by mass of the low refractive index pigment, it is difficult to obtain a practical film strength of the porous layer. Otherwise, the permeability of water into the inside of the porous layer is likely to be impaired.
Since the porous layer has a smaller mixing ratio of the binder resin to the colorant than a general coating film, it is difficult to obtain sufficient film strength. Therefore, among the above binder resins, it is effective to use a nylon resin or a urethane resin in order to increase the abrasion resistance.
Examples of the urethane-based resin include polyester-based urethane resin, polycarbonate-based urethane resin, polyether-based urethane resin, and the like, and two or more of them can be used in combination. In addition, urethane-based emulsion resins in which the resin is emulsified and dispersed in water, and colloids dissolved or dispersed in water by self-emulsification without the need for an emulsifier due to the ionic groups of the urethane resin (urethane ionomer) itself having ionic properties. A dispersion type (ionomer type) urethane resin can also be used.
The urethane-based resin may be either an aqueous urethane-based resin or an oil-based urethane-based resin, but water-based urethane-based resins, particularly urethane-based emulsion resins and colloid-dispersed urethane-based resins, are preferably used.
Although the urethane-based resin can be used alone, other binder resins can also be used in combination depending on the performance required for the film. When a binder resin other than a urethane-based resin is used in combination, it is preferable that the binder resin of the porous layer contains 30% or more of the urethane-based resin in solid content mass ratio in order to obtain a practical film strength.
In the above binder resin, the film strength can be further improved by adding an arbitrary cross-linking agent to the cross-linkable binder resin for cross-linking.
The binder resins have different affinities with water, and by combining them, it is possible to adjust the permeation time into the porous layer, the degree of permeation, and the speed of drying after permeation. Furthermore, the adjustment can be controlled by adding a dispersant or a surfactant as appropriate.

The porous layer is formed by printing means such as screen printing, offset printing, gravure printing, coater, pad printing, transfer, brush coating, spray coating, electrostatic coating, electrodeposition coating, flow coating, roller coating, dip coating, and the like. It can be formed on the colored layer.

Also, a coloring agent can be added to the porous layer to color the porous layer in a dry state.
Examples of the coloring agent include general dyes, general pigments, fluorescent dyes, fluorescent pigments, metallic luster pigments, reversible thermochromic compositions, reversible thermochromic microcapsule pigments containing a reversible thermochromic composition, and photochromic compositions. and a photochromic microcapsule pigment encapsulating a photochromic composition. When a fluorescent colorant such as a fluorescent dye or a fluorescent pigment is used, the clarity of color change is excellent. Thermochromic colorants such as reversible thermochromic microcapsule pigments encapsulating a thermochromic composition, photochromic colorants, photochromic compositions, photochromic microcapsule pigments encapsulating a photochromic composition, etc. A variety of changeability can be imparted by using the photochromic colorant.
The reversible thermochromic composition is preferably a reversible thermochromic composition containing three components: an electron-donating color-developing organic compound, an electron-accepting compound, and an organic compound medium that causes a reversible color reaction. Used.
Photochromic compounds such as spirooxazine-based compounds, spiropyran-based compounds, and diarylethene-based compounds are preferably used as the photochromic composition.

The surface of the porous layer of the water-discoloring sheet has a transparency that covers the water-discolored 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-discolored image. It comprises a cover member.
The transparent base material forming the transparent cover member has transparency to the extent that the water-discolored image can be seen through, and is formed of a plastic sheet material, a plastic molding, or glass.
In addition, a colored transparent transparent base material can also be used.
On the lower surface of the transparent cover member (transparent substrate), the water-discoloring sheet surface and the transparent cover member are held in a non-contact state, and at least three or more protrusions in contact with the water-discoloring sheet surface are arranged non-linearly. can do.
The convex portion forms a space between the porous layer and the transparent cover member, and allows the transparent cover member to contact the porous image and diffuse the water in the image to a portion where the image is not formed. This prevents the outline of the water discoloration image from becoming blurred and unclear.
Contact between the transparent cover member and the porous layer can be prevented by arranging the protrusions in at least three non-linear positions.
Further, the convex portion has a height of 0.4 mm to 12.0 mm, preferably 0.5 mm to 10.0 mm, so that the space between the porous layer and the transparent cover member prevents water from drying. This can be suppressed to improve the function of delaying the disappearance of the water-discolored image.
If the height of the protrusions is less than 0.4 mm, the water-discolored image formed on the water-discolored sheet tends to come into contact with the transparent cover member, and significant bleeding of the water-discolored image and deformation of the image tend to occur. Further, when the height of the convex portion exceeds 12.0 mm, it is difficult to exhibit the effect of suppressing the drying of water, and it becomes difficult to extend the water-discolored image maintenance time.
In addition, when changing the height from 0.4 mm to 12.0 mm, since 0.4 mm can extend the maintenance time of the water discoloration image the most, by setting the height of the convex portion, the water discoloration image is maintained You can adjust the time to
Furthermore, the surface area (s) of the protrusions visible from the upper surface of the transparent cover member and the height (h) of the protrusions satisfy the following formula (1), whereby water discoloration visible through the transparent cover member The function of delaying the disappearance of the water discoloration image can be satisfied without obstructing the visibility of the image due to the convex portion.
1.0≤s/h≤500 (1)
If the ratio s/h is less than 1.0, the shape of the convex portion becomes sharp, which easily damages the porous layer and requires careful handling. Further, when s/h exceeds 500, the surface area of the projections visible from the upper surface of the transparent cover member becomes large, which tends to hinder the visual recognition of the water discoloration image.
In addition, s/h in the formula (1) is preferably 1.0 or more and 400 or less.
Furthermore, the surface area of the upper surface of the cover member is occupied by the protrusions visible from the upper surface of the cover member at 20% or less, preferably 10.0% or less, so that the water discoloration image is visually recognized by the protrusions. You can prevent obstruction.
In addition, the projections are preferably transparent, and when the porous layer is white, it is preferable that the projections are white, so that the visibility of the water discoloration image can be prevented from being hindered by the projections.
Since the tip of the convex portion has a curved surface shape, the porous layer is hardly damaged, the peeling of the porous layer can be prevented, and handling is facilitated even by a small child.
Furthermore, since the transparent cover member has flexibility, the transparent cover member can be easily coated and ^peeled off. By providing the above, it is possible to suitably avoid contact with the water discolored image during use.
Furthermore, one end of the transparent cover member is attached to the water-discolored sheet, and the other end is used as a free end. Convenience that can be covered can be improved.
Furthermore, by forming a water-discoloring body comprising a plurality of water-discoloring sheets and a plurality of transparent cover members, the water-discoloring image can be formed on another water-discoloring sheet before the water-discoloring image dries. Therefore, a desired image can be formed quickly.
The plurality of water-discoloring sheets and the plurality of transparent cover members may be the same in number, but may be configured to have fewer transparent cover members.
Furthermore, a similar effect can be obtained even with a water-discoloring body composed of a plurality of water-discoloring sheets and a single transparent cover member.
Furthermore, by forming a water-discoloring body consisting of a plurality of water-discoloring sheets, a plurality of transparent cover members, and a plurality of transparent sample sheets, which will be described later, a water-discoloring sheet is formed before the water-discoloring image dries. Since a water discoloration image can be formed in a short period of time, a desired image can be formed quickly.
The plurality of water-discoloring sheets, the plurality of transparent cover members, and the plurality of transparent sample sheets may be the same in number, but the number of the transparent cover members and the transparent sample sheets is less than the number of the water-discoloring sheets. It may be a configuration.
Furthermore, a similar effect can be obtained even with a water-discoloring body composed of a plurality of water-discoloring sheets, a single transparent cover member, and a single transparent sample sheet.

In the transparent cover member, the peripheral edge portion of the lower surface of the cover member is in close contact with the surface of the water-discolored sheet, and the inner side of the peripheral edge portion is provided with a gap portion that keeps the surface of the water-discolored sheet in a non-contact state. It is also possible to cover the water-discolored image formed by the adhesion of water to the surface, suppress the drying of the water, and delay the disappearance of the water-discolored image.
The height of the void is 0.4 mm to 12.0 mm, preferably 0.5 mm to 10.0 mm, so that the space between the porous layer and the transparent cover member prevents water from drying. As a result, the function of delaying the disappearance of the water discolored image can be improved.
If the height is less than 0.4 mm, the water-discolored image formed on the water-discolored sheet tends to come into contact with the transparent cover member, and significant bleeding of the water-discolored image and deformation of the image tend to occur. When the height exceeds 12.0 mm, it is difficult to exhibit the effect of suppressing the drying of water, and it becomes difficult to extend the water-discolored image maintenance time.

A pattern such as characters to be formed on the water-discoloring sheet is provided on the transparent cover member, or a pattern such as characters to be formed on the water-discoloring sheet is printed on the transparent cover member. By providing the provided transparent sample sheet, it is possible to visually confirm whether the water discoloration image is formed according to the model, and it is possible to confirm whether the water discoloration image is well-balanced.
The size, shape, color, line width, and line type of the model are not particularly limited, and may be an outline image or an image formed by a plurality of dots.
Further, the transparent model sheet on which the model is provided is formed of a plastic sheet material, a plastic molding, or glass, and the model can be provided by means of printing or the like.
The model may be hiragana, katakana, kanji, alphanumeric characters, and various symbols.
When the surface of the transparent cover member or the surface of the transparent sample sheet has fine irregularities and is non-glossy, it is possible to prevent light from being reflected on the surface and hindering the visibility of the water discoloration image. .
In addition, using a writing instrument such as a whiteboard marker containing erasable ink or an erasable writing instrument such as a writing instrument containing ink that can be erased with water, the surface of the transparent cover member or the surface of the transparent sample sheet You can also write to trace the water discoloration image, or write other characters and marks.
The sample has a light transmittance of 20 to 99%, so that the characters formed on the water-coloring sheet can be visually recognized through the sample formed on the transparent sample sheet. You can clearly see the difference between the model formed on the sheet and the characters written on the water coloring sheet. Also, the light transmittance is preferably 30 to 99%, more preferably 40 to 99%.
The light transmittance refers to the average transmittance in the wavelength range of 400-800 nm.
Furthermore, it is preferable that the color of the porous layer in the dry state, the color of the water discoloration image, and the color of the sample are different, and the sample formed on the transparent sample sheet and the characters written on the water coloring sheet are preferably different. difference can be seen more clearly.

As a means for applying water to the water-discoloring sheet, a hand or finger may be wetted with water to make contact with the sheet, or a water-applying tool may be used.
Examples of the water-applying tool include a water gun, a sprayer, a writing or applicator having a brush tip, a fiber pen body, etc. at the tip, a fibrous body or brush that stores water in a container and draws out water in the container. Writing or applicator, stamp tool, etc. provided with
As the water-adhering tool, a writing tool or applicator in which a plastic porous body having continuous pores or a fiber-processed body is applied as a pen tip member can easily form a written image and can improve practicality.
A water-discoloring body set can be constructed by combining the water-adhering tool and a water-discoloring body, and can be used as a teaching tool set or a drawing toy set.
Examples of the water adhering tool include a writing body and a stamp tool, and the writing body includes a writing brush, a continuous-pore plastic body, felt, a resin-processed or fusion-bonded body of fibers, and a plastic with a capillary gap provided in the inner axial direction. However, it is practical to use a writing utensil in which the above-mentioned member is attached to the barrel as a pen tip so that the water contained in the barrel can be drawn out. .
The stamp tool is a stamp material made of a porous plastic body, a molded plastic body having a rough stamp surface to impart water wettability, or a rotating stamp form in which the above member is attached to the outer periphery of a wheel-shaped rotating body. may be of

Examples are shown below, but the present invention is not limited to the examples. In addition, the part in an Example shows a mass part.
Example 1 (see FIGS. 1 and 2)
Preparation of water discoloration material On a support 3 made of white synthetic paper, 5 parts of a blue pigment, 50 parts of an acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of a silicone antifoaming agent, and 3 parts of a thickener are added. , 2 parts of a wetting agent, 1 part of a leveling agent, 10 parts of water, and 2.5 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and screen printing is performed using a 180-mesh screen plate using a screen printing ink, A colored layer 4 was formed. Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer 5, and a water discoloration sheet 2 having a size of 220 mm × 320 mm. got
Then, as the transparent base material 7, a 1.0 mm-thick, 200 mm×300 mm-thick, 200 mm×300 mm-thick, plate-shaped molding made of a transparent hard ABS resin was formed on the lower surface of a conical shape with a curved tip having a diameter of 10 mm and a height of 1.0 mm. are provided at three positions corresponding to the vertices of an isosceles triangle, and red printing ink having transparency is applied to the upper surface of the plate-shaped molding to form characters (mountains of Chinese characters). A book 9 was provided to obtain a transparent cover member 6 .
The light transmittance of the sample 9 provided on the transparent cover member was 80%.
The surface area (s) of the convex portion visible 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/convex The height (h) of the part was 78.5.
The surface area of the top surface of the transparent cover member was 600 cm ² , and the area occupied by the convex portion visible from the top surface of the transparent cover member was 2.36 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the member was 0.39%.
A water-discoloring body 1 comprising the water-discoloring sheet 2 and the transparent cover member 6 was obtained.

The water discoloration sheet is white in the normal state, but when writing on the porous layer with a writing body having a fiber pen body at the tip and containing water in the barrel, a blue water discoloration image (character) appears. was able to form
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, with a cursive body containing water in the water-discoloring sheet, the letters "mountain" are written to form a blue water-discoloring image, and the tip of the convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so as to be in contact with the surface of the water-discolored sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
Furthermore, when the transparent cover member is placed so that the water discoloration image formed on the water discoloration sheet and the sample overlap, the portion where the blue water discoloration image and the red sample of the transparent cover member overlap becomes red and blue. It was visually recognized as a mixed purple color, and each color was visually recognized in the non-overlapping portions, so it was possible to easily confirm whether or not the water discoloration image was formed accurately according to the model.
In addition, the water-discolored image maintained the same shape as the water-discolored 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-discolored sheet, the water-discolored image gradually disappeared as the water evaporated, and after 10 minutes had passed, the water-discolored sheet was completely decolored and returned to the original water-discolored sheet. This phenomenon could be repeated many times.

Example 2 (see FIGS. 3 and 4)
Preparation of water-discoloring material On a support 3 comprising a polyester nonwoven fabric on a white synthetic paper, 5 parts of a black pigment, 50 parts of an acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of a silicone antifoaming 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 cross-linking agent are uniformly mixed and stirred. Printing was performed to form a colored layer 4 . Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer 5, and a water discoloration sheet 2 having a size of 280 mm × 380 mm. got
Then, as the transparent substrate 7, a white polyurethane resin having a hemispherical shape with a curved tip and a diameter of 3 mm and a height of 1.2 mm was placed on the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 253 mm×353 mm. A transparent cover member 6 was obtained by providing 48 projecting portions 8 formed in a grid pattern at regular intervals of 47 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 7.07 mm ² , the height (h) of the convex portion was 1.2 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 5.89.
The surface area of the upper surface of the transparent cover member was 893.09 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 3.39 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 0.38%, and the number of protrusions per 100 cm ² was 5.37.
Furthermore, a vermilion printing ink having transparency was applied to the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 233 mm×333 mm as the transparent base material 71 . A book 9 was provided to obtain a transparent sample sheet 10 .
The light transmittance of the sample 9 provided on the transparent sample sheet was 90%.
A water-discoloring body comprising the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, the characters "Yamakawa" are written with a brush whose brush tip is dipped in water to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored 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 the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the vermilion sample of the transparent cover member is colored black. However, the portion where the water discoloration image did not overlap with the model was visually recognized in vermilion, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water discolored sheet, the water discolored image gradually disappears as the water evaporates. Went back to color changing sheets. This phenomenon could be repeated many times.
In addition, since the transparent cover member and the transparent sample sheet have flexibility, the water-discolored body can be rolled up and carried, which is excellent in portability.

Example 3
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Next, on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 253 mm×353 mm, a white polyurethane resin having a hemispherical shape with a curved tip and a diameter of 3 mm and a height of 0.6 mm is applied as a transparent substrate. A transparent cover member was obtained by providing 48 projections in a grid pattern at regular intervals of 47 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 7.07 mm ² , the height (h) of the convex portion was 0.5 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 14.14.
The surface area of the upper surface of the transparent cover member was 893.09 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 3.39 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 0.38%, and the number of protrusions per 100 cm ² was 5.37.
Furthermore, as a transparent base material, a transparent vermilion printing ink was applied to the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 253 mm × 353 mm, and a sample of characters (empty kanji characters) was applied. was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent sample sheet was 95%.
A water-discoloring body comprising the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (character) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, a writing brush whose brush tip is dipped in water is used to write the character "empty" to form a black water-discoloring image, and convex portions are formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and the projections prevented the transparent cover member from coming into contact with the water-discolored image, thereby maintaining a clear water-discolored image.
In addition, the water-discolored image maintained the same shape as the water-discolored 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 the transparent cover member so that the water-discolored image and the sample overlap, the overlapping portion of the black water-discolored image and the vermilion sample of the transparent sample sheet is Although it was visually recognized as black, the portions where the water-discolored image did not overlap with the sample were visually recognized in vermillion. Therefore, it was possible to easily confirm whether the water-discolored image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon could be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water-discolored body can be rolled up and carried, which is excellent in portability.

Example 4
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Next, on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 262 mm×362 mm as a transparent substrate, a hemispherical white polyurethane resin with a curved tip and a diameter of 12 mm and a height of 5.0 mm was applied. A transparent cover member was obtained by providing 48 projections in a grid pattern at equal intervals of 38 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 113.04 mm ² , the height (h) of the convex portion was 5.0 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 22.61.
The surface area of the top surface of the transparent cover member was 948.44 cm ² , and the area occupied by the protrusions visible from the top surface of the transparent cover member was 54.26 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 5.72%, and the number of protrusions per 100 cm ² was 5.06.
Furthermore, a model of characters (hiragana sky) was printed on the upper surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 262 mm × 362 mm as a transparent substrate using a blue printing ink having transparency. was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent cover member was 70%.
A water-discoloring body comprising the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, a writing brush whose brush tip is dipped in water is used to write the character "Sora" to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored image immediately after writing even when left for 20 minutes in an environment of 25° C. and 65% RH.
Furthermore, when a transparent sample sheet is placed on the transparent cover member so that the water discoloration image and the sample overlap, the portion where the black water discoloration image overlaps the blue sample of the transparent sample sheet is Although it was visually recognized as black, the part where the water-discolored image did not overlap with the model was visually recognized as blue, so it was possible to easily confirm whether the water-discolored image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon could be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 5
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Next, on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 265 mm×365 mm as a transparent substrate, a hemispherical white polyurethane resin with a curved tip and a diameter of 15 mm and a height of 7.0 mm was applied. A transparent cover member was obtained by providing 48 projections in a grid pattern at equal intervals of 35 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 176.63 mm ² , the height (h) of the convex portion was 7.0 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 25.23.
The surface area of the upper surface of the transparent cover member was 967.25 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 84.78 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 8.77%, and the number of protrusions per 100 cm ² was 4.96.
Furthermore, as a transparent substrate, a model of characters (katakana aiueo) was printed on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 265 mm × 365 mm using a green printing ink having transparency. was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent cover member was 50%.
A water-discoloring body comprising the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, the letters "Aiueo" are written with a brush whose brush tip is dipped in water to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored image immediately after writing even when left for 15 minutes in an environment of 25° C. and 65% RH.
Furthermore, when a transparent sample sheet is placed on the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the green sample of the transparent cover member is colored black. However, the portion where the water discoloration image did not overlap with the model was visually recognized in green, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon could be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 6
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Next, a white polyurethane resin having a hemispherical shape with a curved tip and a diameter of 15 mm and a height of 10.0 mm was placed 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 substrate. A transparent cover member was obtained by providing 48 projections in a grid pattern at equal intervals of 35 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 176.63 mm ² , the height (h) of the convex portion was 10.0 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 17.66.
The surface area of the upper surface of the transparent cover member was 967.25 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 84.78 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 8.77%, and the number of protrusions per 100 cm ² was 4.96.
Furthermore, as a transparent base material, a transparent vermillion printing ink was applied to the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 265 mm × 365 mm, and a model of characters (Chinese characters) was applied. was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent sample sheet was 90%.
A water-discolored body comprising the water-discolored sheet, the transparent cover member and the transparent sample sheet was obtained.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, a brush whose brush tip is dipped in water is used to write the characters "Earth" to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored image immediately after writing even when left for 10 minutes in an environment of 25° C. and 65% RH.
Furthermore, when a transparent sample sheet is placed on the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the vermilion sample of the transparent cover member is colored black. However, the portion where the water discoloration image did not overlap with the model was visually recognized in vermilion, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon can be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 7
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Next, on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 265 mm×365 mm, a white polyurethane resin having a hemispherical shape with a curved tip and a diameter of 15 mm and a height of 0.5 mm was applied as a transparent substrate. A transparent cover member was obtained by providing 48 projections in a grid pattern at equal intervals of 35 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 176.63 mm ² , the height (h) of the convex portion was 0.5 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 353.33.
The surface area of the upper surface of the transparent cover member was 967.25 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 84.78 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 8.77%, and the number of protrusions per 100 cm ² was 4.96.
Furthermore, as a transparent base material, a transparent vermillion printing ink was applied to the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 265 mm × 365 mm, and a model of characters (Chinese characters) was applied. was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent sample sheet was 90%.
A transparent cover member and a transparent sample sheet were attached to one end of the water-discolored sheet, and the other end was used as a free end to obtain a water-discolored body.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, a brush whose brush tip is dipped in water is used to write the characters "Earth" to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored 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 the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the vermilion sample of the transparent cover member is colored black. However, the portion where the water discoloration image did not overlap with the model was visually recognized in vermilion, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon can be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 8
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Then, as a transparent base material, a flexible polyester transparent sheet having a thickness of 50 μm and a size of 255 mm×355 mm was applied to the lower surface of a flexible polyester sheet having a diameter of 5 mm and a height of 10.0 mm. A transparent cover member was obtained by providing 48 protrusions made of SEBS resin in a grid pattern at regular intervals of 45 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 19.63 mm ² , the height (h) of the convex portion was 10.0 mm, and the surface area of the convex portion (s)/convex The height (h) of the part was 1.96.
The surface area of the upper surface of the transparent cover member was 905.25 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 9.42 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 1.04%, and the number of protrusions per 100 cm ² was 5.30.
Furthermore, as a transparent base material, a transparent vermillion printing ink was applied to the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 265 mm × 365 mm, and a model of characters (Chinese characters) was applied. was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent sample sheet was 90%.
A transparent cover member and a transparent sample sheet were attached to one end of the water discolored sheet, and the other end was used as a free end to obtain a water discolored body.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, a brush whose brush tip is dipped in water is used to write the characters "Earth" to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored image immediately after writing even when left for 10 minutes in an environment of 25° C. and 65% RH.
Furthermore, when a transparent sample sheet is placed on the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the vermilion sample of the transparent cover member is colored black. However, the portion where the water discoloration image did not overlap with the model was visually recognized in vermilion, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon can be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 9
On a support made of red polyester satin fabric with a basis weight of 130 g/m ² , 15 parts of particulate silicic acid produced by a wet process [trade name: Nip Seal E-200A, manufactured by Nippon Silica Kogyo Co., Ltd.], and a binder resin. As water-based urethane resin [trade name: Hydran AP-10, polyester urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts , 3 parts of a water-based ink thickener, 1 part of ethylene glycol, and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred to form a porous layer by performing solid printing on the entire surface using a white screen printing ink. A water discolored sheet with a size of 410 mm was obtained.
Then, as a transparent base material, a flexible transparent sheet made of flexible PVC having a thickness of 200 μm and a size of 310 mm×410 mm was formed on the lower surface of a transparent transparent sheet having a diameter of 10 mm and a height of 3.0 mm. A transparent cover member was obtained by providing 63 protrusions made of a soft PVC resin at intervals of 40 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 78.5 mm ² , the height (h) of the convex portion was 3.0 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 26.17.
The surface area of the upper surface of the transparent cover member was 1271 cm ^{2 , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 49.46 cm 2 .} The occupied area ratio of the protrusions visible from the upper surface of the member was 3.9%, and the number of protrusions per 100 cm ² was 4.95.
Furthermore, a transparent green printing ink was applied to the lower surface of a flexible polyester transparent sheet having a thickness of 100 μm and a size of 300 mm × 400 mm as a transparent base material, and a model of characters (Chinese characters) was applied. was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent cover member was 80%.
A transparent cover member and a transparent sample sheet were attached to one end of the water discolored sheet, and the other end was used as a free end to obtain a water discolored body.

The water-discoloring sheet was white in the normal state, but a red water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water discoloration image was maintained for 3 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water discoloration sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, a letter "Earth" is written with a cursive body containing water in the brush tip to form a water-discoloring image, and the tip of the convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the surface of the water-discolored sheet was in contact with the surface of the water-discolored sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
Furthermore, when a transparent sample sheet is placed on the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the red water discoloration image and the green sample of the transparent cover member becomes red. It was visually recognized as a black mixed color of green, and each color was visually recognized in the non-overlapping portions, so it was possible to easily confirm whether or not the water discoloration image was formed accurately according to the model.
In addition, the water-discolored image maintained the same shape as the water-discolored image immediately after writing even when left for 20 minutes in an environment of 25° C. and 65% RH.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon can be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 10
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Next, 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 substrate, a hemispherical white polyurethane resin with a curved tip and a diameter of 3 mm and a height of 0.4 mm is applied. A transparent cover member was obtained by providing 48 projections in a grid pattern at regular intervals of 47 mm.
The surface area (s) of the convex portion visible 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 of the convex portion (s)/convex The height (h) of the part was 17.68.
The surface area of the upper surface of the transparent cover member was 893.09 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 3.39 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 0.38%, and the number of protrusions per 100 cm ² was 5.37.
Furthermore, characters (Kanji 123) were printed on the lower surface of a flexible polyester transparent sheet having a thickness of 50 µm and a size of 260 mm x 360 mm as a transparent substrate using vermilion printing ink having transparency. A sample was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent sample sheet was 90%.
A transparent cover member and a transparent sample sheet were attached to one end of the water discolored sheet, and the other end was used as a free end to obtain a water discolored body.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, write the characters "123" with a brush dipped in water to form a black water-discoloring image, and on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tips of the projections were in contact with the surface of the water-discolored sheet.
The water-discolored image was clearly visible through the transparent cover member. In addition, although a part of the water-discolored image came into contact with the transparent cover member and caused some bleeding, there was no practical problem, and a clear water-discolored image could be maintained.
In addition, the water-discolored image maintained the same shape as the water-discolored 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 the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the vermilion sample of the transparent cover member is colored black. However, the portion where the water discoloration image did not overlap with the model was visually recognized in vermilion, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon could be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 11
Preparation of Water-Discoloring Material A water-discoloring sheet was obtained in the same manner as in Example 2.
Then, as a transparent substrate, a flexible polyester transparent sheet with a thickness of 50 μm and a size of 265 mm×365 mm was placed on the lower surface of a white polyurethane resin having a diameter of 15 mm and a height of 12.0 mm and a conical shape with a curved tip. A transparent cover member was obtained by providing 48 projections in a grid pattern at equal intervals of 35 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 176.63 mm ² , the height (h) of the convex portion was 12.0 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 14.72.
The surface area of the upper surface of the transparent cover member was 967.25 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 84.78 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 8.77%, and the number of protrusions per 100 cm ² was 4.96.
Furthermore, characters (○△× symbols) were printed 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 using pink printing ink having transparency. A sample was provided to obtain a transparent sample sheet.
The light transmittance of the sample provided on the transparent sample sheet was 60%.
A water-discolored body comprising the water-discolored sheet, the transparent cover member and the transparent sample sheet was obtained.

The water-discoloring sheet exhibits a white color in a normal state, but when writing on the porous layer with a writing body containing water in the barrel, a black water-discoloring image (character) is formed. could be formed.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, write the characters "○ △ ×" with a brush soaked in water to form a black water-discoloring image, and on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tips of the projections were in contact with the surface of the water-discolored sheet.
The water-discolored image can be clearly seen through the transparent cover member, and the transparent cover member does not come into contact with the water-discolored image due to the convex portion, so that a clear water-discolored image can be observed at 25° C. and 65% RH. The image was maintained for 7 minutes under ambient conditions.
Furthermore, when a transparent sample sheet is placed on the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the pink sample of the transparent cover member becomes black. However, since the portion where the water discoloration image did not overlap with the model was visually recognized in pink, it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
The water-discolored image gradually disappeared as the water evaporated, and after 15 minutes had passed, the water-discolored sheet was entirely white.
This phenomenon can be repeated many times.
In addition, since the transparent sample sheet and the transparent cover member have flexibility, the water discoloration body can be rolled up and carried, which is excellent in portability.

Example 12 (see FIG. 5)
Preparation of water discoloration material On a support 3 made of white synthetic paper, 5 parts of a blue pigment, 50 parts of an acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of a silicone antifoaming agent, and 3 parts of a thickener are added. , 2 parts of a wetting agent, 1 part of a leveling agent, 10 parts of water, and 2.5 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and screen printing is performed using a 180-mesh screen plate using a screen printing ink, A colored layer 4 was formed. Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer 5, and a water-discoloring sheet having a size of 220 mm × 320 mm. Obtained.
Then, as the transparent base material 7, the lower surface with a thickness of 1.0 mm and a size of 200 mm × 300 mm is in close contact with the surface of the water-discolored sheet, and the inner part of the peripheral part is kept in a non-contact state with the surface of the water-discolored sheet. A transparent cover member made of a transparent hard ABS resin having a gap of 5 mm and having a pattern 9 of characters (a pile of Chinese characters) provided on the upper surface thereof using transparent pink printing ink was obtained. .
The light transmittance of the sample 9 provided on the transparent cover member was 90%.
A water-discoloring body comprising the water-discoloring sheet and the transparent cover member was obtained.

The water discoloration sheet is white in the normal state, but when writing on the porous layer with a writing body having a fiber pen body at the tip and containing water in the barrel, a blue water discoloration image (character) appears. was able to form
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, a letter "mountain" is written on the water-discoloring sheet with a cursive hand containing water to form a blue water-discoloring image, and a transparent cover member is placed on the water-discoloring sheet on which the water-discoloring image is formed. placed.
The water-discolored image was able to maintain a clear water-discolored image through the transparent cover member.
Furthermore, when the transparent cover member is placed so that the water-discolored image formed on the water-discolored sheet and the sample overlap each other, the portions where the blue water-discolored image and the pink sample of the transparent cover member overlap are blue and pink. It was visually recognized as a purple mixture of colors, and each color was visually recognized in the non-overlapping portions, so it was possible to easily confirm whether or not the water discoloration image was formed accurately according to the model.
In addition, the water-discolored image maintained the same shape as the water-discolored image immediately after writing even when left for 30 minutes in an environment of 25° C. and 65% RH.
Then, when the transparent cover member was removed from the water-discolored sheet, the water-discolored image gradually disappeared as the water evaporated, and after 10 minutes had passed, the water-discolored sheet was completely decolored and returned to the original water-discolored sheet. This phenomenon could be repeated many times.

Example 13 (see FIG. 6)
Preparation of water discoloration material On a support 3 made of white synthetic paper, 5 parts of a blue pigment, 50 parts of an acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of a silicone antifoaming agent, and 3 parts of a thickener are added. , 2 parts of a wetting agent, 1 part of a leveling agent, 10 parts of water, and 2.5 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and screen printing is performed using a 180-mesh screen plate using a screen printing ink, A colored layer 4 was formed. Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer 5, and a water-discoloring sheet having a size of 220 mm × 320 mm. Obtained.
Furthermore, the transparent base material 7 has a thickness of 1.0 mm and a size of 200 mm x 300 mm. A transparent cover member made of a transparent hard ABS resin having a gap of 10 mm was obtained.
Furthermore, a yellow printing ink having transparency was applied to the lower surface of a flexible polyester transparent sheet having a thickness of 50 μm and a size of 200 mm×300 mm as the transparent base material 71. A book 9 was provided to obtain a transparent sample sheet.
The light transmittance of the sample 9 provided on the transparent sample sheet was 98%.
A water-discoloring body comprising the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

The water discoloration sheet is white in the normal state, but when writing on the porous layer with a writing body having a fiber pen body at the tip and containing water in the barrel, a blue water discoloration image (character) appears. was able to form
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, the characters "12345" are written on the water-discoloring sheet with a writing body containing water to form a blue water-discoloring image, and a transparent cover member is placed on the water-discoloring sheet on which the water-discoloring image is formed. placed.
The water-discolored image was able to maintain a clear water-discolored image through the transparent cover member.
Furthermore, when a transparent sample sheet is placed on the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the blue water discoloration image and the yellow sample of the transparent sample sheet is It was visually recognized as green, which was a mixture of blue and yellow, and each color was visually recognized in the non-overlapping portions, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
In addition, the water-discolored image maintained the same shape as the water-discolored image immediately after writing even when left for 30 minutes in an environment of 25° C. and 65% RH.
Next, when the transparent sample sheet and the transparent cover member are removed from the water-discolored sheet, the water-discolored image gradually disappears as the water evaporates. I returned to my seat. This phenomenon could be repeated many times.

Example 14
Preparation of water discoloration body set (see FIG. 7)
A water-discoloring body set 12 was obtained by combining the water-discoloring body 1 of Example 1 and a water-adhering tool 11 (cursive body containing water).
The water-discoloring body set can form a water-discoloring image on a water-discoloring sheet using a water adhering tool. The water-discolored image was clearly visible through the member, and a clear water-discolored image could be maintained for a long time without the transparent cover member coming into contact with the water-discolored image due to the projections.
Furthermore, since a model is provided on the transparent cover member, it is possible to visually confirm whether the water discoloration image is formed according to the model, and it is possible to confirm whether the water discoloration image is formed accurately in a well-balanced manner. was made.
Further, a set of water-discoloring bodies was obtained by combining each water-discoloring body of Examples 2 to 11 with a water-adhering tool (a writing body containing water).
The water discoloration body set can form a water discoloration image on a water discoloration sheet using a water adhesion tool, and the water discoloration image can be made transparent by placing a transparent cover member in the same manner as in Examples 2 to 11. The water-discolored image was clearly visible through the transparent cover member, and the clear water-discolored image could be maintained for a long period of time without the transparent cover member coming into contact with the water-discolored image.
Furthermore, when the transparent sample sheet is placed on the transparent cover member, since the transparent cover member is provided with a sample, it is possible to visually confirm whether the water discoloration image is formed according to the sample. It was possible to confirm whether the discoloration image could be accurately formed in a well-balanced manner.
Further, a water-discoloring body set was obtained by combining the water-discoloring body of Example 12 and a water-adhering tool (cursive body containing water).
The water-discoloring body set can form a water-discoloring image on a water-discoloring sheet using a water adhering tool. The water-discolored image was clearly visible through the member, and a clear water-discolored image could be maintained for a long time without the transparent cover member coming into contact with the water-discolored image due to the gap.
Furthermore, since a model is provided on the transparent cover member, it is possible to visually confirm whether the water discoloration image is formed according to the model, and it is possible to confirm whether the water discoloration image is formed accurately in a well-balanced manner. was made.
Moreover, a water-discoloring body set was obtained by combining the water-discoloring body of Example 13 and a water-adhering tool (cursive body containing water).
The water discoloration body set can form a water discoloration image on a water discoloration sheet using a water adhesion tool. The water-discolored image was clearly visible through the member, and a clear water-discolored image could be maintained for a long time without the transparent cover member coming into contact with the water-discolored image due to the gap.
Furthermore, when the transparent sample sheet is placed on the transparent cover member, since the transparent cover member is provided with a sample, it is possible to visually confirm whether the water discoloration image is formed according to the sample. It was possible to confirm whether the discoloration image could be accurately formed in a well-balanced manner.

Example 15
Preparation of water discoloration body On a support made of white synthetic paper, 5 parts of blue pigment, 50 parts of acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of silicone antifoaming agent, 3 parts of thickener, 2 parts of a wetting agent, 1 part of a leveling agent, 10 parts of water, and 2.5 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred to form a screen printing ink. formed a layer. Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer, thereby obtaining a water discoloration sheet having a size of 220 mm × 320 mm. rice field.
Next, as a transparent base material, a plate-shaped molded product having a thickness of 1.0 mm and a size of 200 mm x 300 mm, the upper surface of which has fine irregularities and is made of a transparent hard acrylonitrile resin having a non-glossy surface, has a diameter of 10 mm. , Three projections made of transparent ABS resin having a curved conical tip with a height of 1.0 mm are provided at positions corresponding to the vertices of an isosceles triangle, and transparent red printing is printed on the upper surface of the plate-shaped molding. A transparent cover member 6 was obtained by providing a model of characters (piles of Chinese characters) using ink.
The light transmittance of the sample provided on the transparent cover member was 80%.
The surface area (s) of the convex portion visible 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/convex The height (h) of the part was 78.5.
The surface area of the top surface of the transparent cover member was 600 cm ² , and the area occupied by the convex portion visible from the top surface of the transparent cover member was 2.36 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the member was 0.39%.
A water-discoloring body comprising the water-discoloring sheet and the transparent cover member was obtained.

The water discoloration sheet is white in the normal state, but when writing on the porous layer with a writing body having a fiber pen body at the tip and containing water in the barrel, a blue water discoloration image (character) appears. was able to form
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, with a cursive body containing water in the water-discoloring sheet, the letters "mountain" are written to form a blue water-discoloring image, and the tip of the convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so as to be in contact with the surface of the water-discolored sheet.
The water-discolored image can be seen more clearly through the transparent cover member without impeding visibility due to reflection of light on the surface of the transparent cover member. A clear water discoloration image could be maintained without contact with the liquid.
Furthermore, when a photograph was taken in a room with the transparent cover member placed thereon, there was no migration of the lighting equipment, and a clear image discolored by water could be photographed.
Furthermore, when the transparent cover member is placed so that the water discoloration image formed on the water discoloration sheet and the sample overlap, the portion where the blue water discoloration image and the red sample of the transparent cover member overlap becomes red and blue. It was visually recognized as a mixed purple color, and each color was visually recognized in the non-overlapping portions, so it was possible to easily confirm whether or not the water discoloration image was formed accurately according to the model.
In addition, the water-discolored image maintained the same shape as the water-discolored 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-discolored sheet, the water-discolored image gradually disappeared as the water evaporated, and after 10 minutes had passed, the water-discolored sheet was completely decolored and returned to the original water-discolored sheet. This phenomenon could be repeated many times.
Furthermore, by combining the water discoloration body and an erasable writing instrument (whiteboard marker), the surface of the transparent cover member is written with a whiteboard marker to point out unskilled portions of the water discoloration image. and could be scored. Further, by rubbing the surface of the transparent cover member with a dry cloth or whiteboard eraser, the handwriting of the marker could be easily removed.

Example 16
Preparation of water discoloration body On a support made of white synthetic paper, 5 parts of blue pigment, 50 parts of acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of silicone antifoaming agent, 3 parts of thickener, 2 parts of a wetting agent, 1 part of a leveling agent, 10 parts of water, and 2.5 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred to form a screen printing ink. formed a layer. Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer, and a water-discoloring sheet (3 ) was obtained.
Next, as a transparent base material, a conical shape with a curved tip having a diameter of 10 mm and a height of 1.0 mm was placed on the lower surface of a plate-shaped molding made of transparent hard ABS resin having a thickness of 1.0 mm and a size of 200 mm x 300 mm. Three protrusions made of transparent ABS resin are provided at positions corresponding to the vertices of an isosceles triangle, and a model of characters (a pile of Chinese characters) is printed on the upper surface of the plate-shaped molded product using transparent red printing ink. to obtain a transparent cover member (2 pieces).
The light transmittance of the sample provided on the transparent cover member was 80%.
The surface area (s) of the convex portion visible 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/convex The height (h) of the part was 78.5.
The surface area of the top surface of the transparent cover member was 600 cm ² , and the area occupied by the convex portion visible from the top surface of the transparent cover member was 2.36 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the member was 0.39%.
A water-discoloring body comprising the water-discoloring sheets (3 sheets) and the transparent cover members (2 sheets) was obtained.

The water discoloration sheet is white in the normal state, but when writing on the porous layer with a writing body having a fiber pen body at the tip and containing water in the barrel, a blue water discoloration image (character) appears. was able to form
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, with a cursive body containing water in the water-discoloring sheet, the letters "mountain" are written to form a blue water-discoloring image, and the tip of the convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so as to be in contact with the surface of the water-discolored sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
Furthermore, when the transparent cover member is placed so that the water discoloration image formed on the water discoloration sheet and the sample overlap, the portion where the blue water discoloration image and the red sample of the transparent cover member overlap becomes red and blue. It was visually recognized as a mixed purple color, and each color was visually recognized in the non-overlapping portions, so it was possible to easily confirm whether or not the water discoloration image was formed accurately according to the model.
In addition, the water-discolored image maintained the same shape as the water-discolored 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-discolored sheet, the water-discolored image gradually disappeared as the water evaporated, and after 10 minutes had passed, the water-discolored sheet was completely decolored and returned to the original water-discolored sheet. This phenomenon could be repeated many times.
Further, after removing the transparent cover member from the water-discoloring sheet, the water-discoloring image is formed on another water-discoloring sheet before completely erasing the color and returning to the original water-discoloring sheet, and the transparent cover member is placed. By doing so, it was possible to quickly form an image.

Example 17
Preparation of water discoloration body On a support of polyester nonwoven fabric on white synthetic paper, 5 parts of black pigment, 50 parts of acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of silicone antifoaming agent, 3 parts of sticky agent, 2 parts of wetting agent, 1 part of leveling agent, 10 parts of water, and 2.5 parts of epoxy cross-linking agent are uniformly mixed and stirred. was performed to form a colored layer. Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer, thereby obtaining a water-discoloring sheet having a size of 280 mm × 380 mm. rice field.
Next, on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 253 mm×353 mm, a hemispherical white polyurethane resin with a curved tip and a diameter of 3 mm and a height of 1.2 mm was applied as a transparent substrate. A transparent cover member was obtained by providing 48 projections in a grid pattern at regular intervals of 47 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 7.07 mm ² , the height (h) of the convex portion was 1.2 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 5.89.
The surface area of the upper surface of the transparent cover member was 893.09 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 3.39 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 0.38%, and the number of protrusions per 100 cm ² was 5.37.
Further, as a transparent substrate, a polyester transparent sheet having a thickness of 50 μm and a size of 233 mm×333 mm having fine irregularities on the upper surface and having non-gloss and flexibility has a vermilion color having transparency on the lower surface. A transparent model sheet was obtained by providing a model of characters (Yamakawa in Kanji) using printing ink.
The light transmittance of the sample provided on the transparent sample sheet was 90%.
A water-discoloring body comprising the water-discoloring sheet, the transparent cover member, and the transparent sample sheet was obtained.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, the characters "Yamakawa" are written with a brush whose brush tip is dipped in water to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored 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 is placed on the transparent cover member so that the water-discolored image and the sample overlap, the water-discolored image reflects light on the surface of the transparent sample sheet and hinders visibility. can be seen more clearly through the transparent sample sheet, and the portion where the black water-discolored image and the vermilion sample of the transparent cover member overlap is seen as black, but the water-discolored image Since the portion where the pattern did not overlap with the model was visible in vermilion, it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Furthermore, when a photograph was taken in a room with the transparent sample sheet placed thereon, a clear water discoloration image could be photographed without any transfer of lighting fixtures.
Next, when the transparent sample sheet and the transparent cover member are removed from the water discolored sheet, the water discolored image gradually disappears as the water evaporates. Went back to color changing sheets. This phenomenon could be repeated many times.
In addition, since the transparent cover member and the transparent sample sheet have flexibility, the water-discolored body can be rolled up and carried, which is excellent in portability.

Example 18
Preparation of water discoloration body On a support of polyester nonwoven fabric on white synthetic paper, 5 parts of black pigment, 50 parts of acrylic acid ester emulsion (solid content: 50% by weight), 0.2 parts of silicone antifoaming agent, 3 parts of sticky agent, 2 parts of wetting agent, 1 part of leveling agent, 10 parts of water, and 2.5 parts of epoxy cross-linking agent are uniformly mixed and stirred. was performed to form a colored layer. Next, on the colored layer, 15 parts of particulate silicic acid [trade name: Nip Seal E-200A, manufactured by Nippon Silica Industry Co., Ltd.] manufactured by a wet method, and a water-based urethane resin [trade name: Hydran AP-] as a binder resin. 10, polyester-based urethane resin, solid content 30% by weight, manufactured by Dainippon Ink and Chemicals Co., Ltd.] 50 parts, water 30 parts, silicone antifoaming agent 0.5 parts, water-based ink thickener 3 parts, ethylene glycol 1 part and 2 parts of an epoxy-based cross-linking agent are uniformly mixed and stirred, and the entire surface is solidly printed using a stirred white screen printing ink to form a porous layer, and a water-discoloring sheet (3 ) was obtained.
Next, on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 253 mm×353 mm, a hemispherical white polyurethane resin with a curved tip and a diameter of 3 mm and a height of 1.2 mm was applied as a transparent substrate. A transparent cover member (two sheets) was obtained by providing 48 convex portions in a grid pattern at regular intervals of 47 mm.
The surface area (s) of the convex portion visible from the upper surface of the transparent cover member was 7.07 mm ² , the height (h) of the convex portion was 1.2 mm, and the surface area (s) of the convex portion/convex The height (h) of the part was 5.89.
The surface area of the upper surface of the transparent cover member was 893.09 cm ² , and the area occupied by the protrusions visible from the upper surface of the transparent cover member was 3.39 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the protective cover member was 0.38%, and the number of protrusions per 100 cm ² was 5.37.
Furthermore, as a transparent substrate, a model of characters (Kanji Yamakawa) was printed on the lower surface of a flexible polyester transparent sheet with a thickness of 50 μm and a size of 233 mm × 333 mm using a transparent vermilion printing ink. was provided to obtain transparent sample sheets (2 sheets).
The light transmittance of the sample provided on the transparent sample sheet was 90%.
A water-discolored body comprising the water-discolored sheets (3 sheets), the transparent cover members (2 sheets) and the transparent sample sheets (2 sheets) was obtained.

The water-discoloring sheet was white in the normal state, but a black water-discoloring image (characters) could be formed by writing on the porous layer with a brush whose bristles were dipped in water.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, on the water-discoloring sheet, the characters "Yamakawa" are written with a brush whose brush tip is dipped in water to form a black water-discoloring image, and a convex portion is formed on the water-discoloring sheet on which the water-discoloring image is formed. The transparent cover member was placed so that the tip was in contact with the surface of the water-discoloring sheet.
The water-discolored image was clearly visible through the transparent cover member, and a clear water-discolored image could be maintained without the transparent cover member coming into contact with the water-discolored image due to the projections.
In addition, the water-discolored image maintained the same shape as the water-discolored 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 the transparent cover member so that the water discoloration image and the sample overlap, the overlapping portion of the black water discoloration image and the vermilion sample of the transparent cover member is colored black. However, the portion where the water discoloration image did not overlap with the model was visually recognized in vermilion, so it was possible to easily confirm whether the water discoloration image was formed accurately according to the model.
Next, when the transparent sample sheet and the transparent cover member are removed from the water discolored sheet, the water discolored image gradually disappears as the water evaporates. Went back to color changing sheets. This phenomenon could be repeated many times.
In addition, since the transparent cover member and the transparent sample sheet have flexibility, the water-discolored body can be rolled up and carried, which is excellent in portability.
Further, after removing the transparent cover member and the transparent sample sheet from the water-discoloring sheet, before completely erasing the color and returning to the original water-discoloring sheet, a water-discoloring image is formed on another water-discoloring sheet to form a transparent sheet. By placing a transparent cover member and a transparent sample sheet, an image could be formed quickly.

Comparative example 1
Preparation of water-discoloring body A water-discoloring sheet was obtained in the same manner as in Example 1.
Next, as a transparent base material, a conical shape with a curved tip having a diameter of 10 mm and a height of 1.0 mm was placed on the lower surface of a plate-shaped molding made of transparent hard ABS resin having a thickness of 1.0 mm and a size of 200 mm x 300 mm. A transparent cover member was obtained by providing two projecting portions made of transparent ABS resin on the plate-like molding.
The surface area (s) of the convex portion visible 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/convex The height (h) of the part was 78.5.
The surface area of the top surface of the transparent cover member was 600 cm ² , and the area occupied by the convex portion visible from the top surface of the transparent cover member was 2.36 cm ² . The occupied area ratio of the protrusions visible from the upper surface of the member was 0.39%.
A water-discoloring body comprising the water-discoloring sheet and the transparent cover member was obtained.

The water-discoloring sheet was white in the normal state, but when writing on the porous layer with a pen containing water, a blue water-discoloring image could be formed.
The water-discolored image was maintained for 5 minutes in an environment of 25° C. and 65% RH, but gradually disappeared as the water evaporated, and after 10 minutes, the entire surface became a white water-discolored sheet. I'm back. This phenomenon could be repeated many times.
Next, a water-discolored image is formed by writing with a writing body containing water on the water-discolored sheet, and the tips of the convex portions on the water-discolored sheet on which the water-discolored image is formed are in contact with the surface of the water-discolored sheet. The transparent cover member was placed.
Although the water-discolored image could be visually recognized through the transparent cover member, there was a portion where the transparent cover member and the water-discolored image came into contact with each other, and bleeding occurred in the water-discolored image.
In addition, when the water-discolored image is left in an environment of 25° C. and 65% RH, a difference occurs in the distance between the transparent cover member and the water-discolored image. It was not possible to maintain a good water discoloration image.

REFERENCE SIGNS LIST 1 water-discoloring body 2 water-discoloring sheet 3 support 4 colored layer 5 porous layer 6 transparent cover member 7, 71 transparent base material 8 convex portion 9 sample 10 transparent sample sheet 11 void 12 water adhesion tool 13 water discoloration set

Claims (19)

Covering a water-discoloring sheet having a porous layer in which a low refractive index pigment is fixed in a dispersed state to a binder resin as an upper layer of a colored layer, and a water-discoloring image formed by adhesion of water on the surface of the porous layer, Water-discoloring, comprising a transparent cover member for suppressing drying of water and delaying disappearance of the water-discolored image, wherein the transparent cover member is provided with a model of characters to be formed on the water-discoloring sheet. body. Covering a water-discoloring sheet having a porous layer in which a low refractive index pigment is fixed in a dispersed state to a binder resin as an upper layer of a colored layer, and a water-discoloring image formed by adhesion of water on the surface of the porous layer, A water-discoloring body comprising a transparent cover member for suppressing drying of water and delaying disappearance of a water-discoloring image, and a transparent sample sheet provided with a sample of characters to be formed on the water-discoloring sheet. The transparent cover member maintains the water-discoloring sheet surface and the transparent cover member in a non-contact state on the lower surface of the transparent cover member, and at least three or more protrusions in contact with the water-discoloring sheet surface are arranged non-linearly. 3. The water discoloration material according to 1 or 2. 4. The water discoloration body according to claim 3, wherein said projections have a height of 0.4 mm to 12.0 mm. 5. The water discoloring body according to claim 4, wherein the surface area (s) of the projections viewed from the upper surface of the transparent cover member and the height (h) of the projections satisfy the following formula (1).
1.0≤s/h≤500 (1) 6. The water-discoloring article according to claim 3, wherein the occupied area of the projections visible from the upper surface of the transparent cover member is 20% or less of the surface area of the upper surface of the transparent cover member. 7. The water discoloring body according to any one of claims 3 to 6, wherein said projections are transparent. 7. The water discoloring body according to any one of claims 3 to 6, wherein said convex portion is white. 9. The water discolored body according to any one of claims 3 to 8, wherein the tip of the projection has a curved shape. 10. The water discoloration body according to any one of claims 3 to 9, wherein the transparent cover member has flexibility, and the number of the protrusions is 3 or more per 100 cm< ² >. 11. The water-color body according to any one of claims 1 to 10, wherein the surface of the transparent cover member is non-glossy. 11. The water discoloration body according to any one of claims 2 to 10, wherein the surface of the transparent sample sheet is non-glossy. 3. The water discoloration according to claim 1 or 2, wherein the periphery of the lower surface of the transparent cover member is in close contact with the surface of the water discoloration sheet, and the inside of the periphery has a gap for keeping the surface of the water discoloration sheet in a non-contact state. body. 14. The water according to any one of claims 1 to 13, wherein the transparent cover member has one end attached to the water-discoloring sheet and the other end serving as a free end, and is provided on the water-discoloring sheet so as to be openable and closable. discoloration body. 14. The water-discoloring body according to any one of claims 1 to 13, comprising a plurality of said water-discoloring sheets and a plurality of said transparent cover members. 14. The water-discoloring body according to any one of claims 1 to 13, comprising a plurality of said water-discoloring sheets, a plurality of said transparent cover members, and a plurality of said transparent sample sheets. 17. The water discoloration body according to any one of claims 1 to 16, wherein the sample has a light transmittance of 20 to 99%. 18. The water-discoloring article according to any one of claims 1 to 17, wherein the porous layer has a color in a dry state, a color in the water-discoloring image, and a color in the sample. A water-discoloring body set comprising the water-discoloring body according to any one of claims 1 to 18 and a water adhesion tool for forming a water-discoloring image.

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