JP2007076052A - Reversibly discoloring writing plate and reversibly discoloring writing set using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reversibly discoloring writing plate which enables writing in a state that it is held and which has strength enough to eliminate possible damage in use and is lightweight and excellent in carrying properties, and a reversibly discoloring writing set using the same. <P>SOLUTION: The writing plate has a constitution wherein a porous layer 3 having a low-refractive-index pigment fixed in a dispersed state to a binder resin and having different transparencies between a state of liquid absorption and a state of non-liquid absorption is provided on the surface of a plate-shaped foam 2 having a hardness of 5-95. A colored image 6 is formed on the porous layer 3. The writing set is comprised of the reversibly discoloring writing plate 1 and a water applying means selected from among a writing implement, a coating implement and a stamping implement to which either a plastic porous body having continuous pores or a fibrous processed body is used as a penpoint member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reversible color-changing writing board and a reversible color-changing writing set using the same. Furthermore, the present invention relates to a reversible color-changing writing board capable of repeated writing and a reversible color-changing writing set using the same.

Conventionally, a water pen paper that can be repeatedly written by the adhesion of a liquid has been disclosed (for example, see Patent Document 1).
The water brush paper can draw an arbitrary image with water, etc., and can be drawn and written repeatedly after the handwriting is dried, and it is lightweight, but the support is made of paper, so the user has it. I couldn't write. In addition, when used by infants and the like, they may be accidentally broken during use or storage.
Japanese Utility Model Publication No. 52-44103

  The present invention is a writing object that can draw an arbitrary image with water or the like, and can be written in a held state, and has a strength that does not cause damage during use, and is lightweight and excellent in portability. An object of the present invention is to provide a reversible color-changing writing board and a reversible color-changing writing set using the same.

The present invention is a porous material in which a low refractive index pigment is fixed to a binder resin in a dispersed state on the surface of a plate-like foam having a hardness of 5 to 95, and the transparency is different between a liquid absorbing state and a non-liquid absorbing state. A reversible color-changing writing board provided with a layer is a requirement.
Further, the back surface of the plate-like foam is provided with a porous layer having a low refractive index pigment fixed to a binder resin in a dispersed state and having different transparency in a liquid absorption state and a non-liquid absorption state. As a requirement.
Furthermore, the tensile strength of the foam is 0.6 kg / m ² or more, the surface area of the porous layer provided on the foam is 100 to 8000 cm ² , and a colored image is formed on the porous layer. It is formed, a cloth or a plastic film is interposed between the plate-like foam and the porous layer, the cloth is selected from a woven fabric, a knitted fabric, a braid, and a non-woven fabric, and the fabric or plastic It is a requirement that a colored layer is interposed between the film and the porous layer, and that the foam is provided with a grip portion.
Furthermore, the reversible color-changing writing set comprising any one of the reversible color-changing writing board and the water adhering means is a requirement, and the water adhering means uses a plastic porous body or fiber processed body having continuous pores as a nib member. It is required to be selected from any of the applied writing instrument, application tool, or stamp tool.

  The present invention is a reversible color-changing writing board that is lightweight and easy to carry while being able to be written in a holding state without being damaged during use by using a foam having a specific strength as a support. And a reversible color-changing writing set using the same.

The porous layer formed on the surface or both surfaces of the plate-like foam is a layer in which a low refractive index pigment is fixed in a dispersed state together with a binder resin.
Examples of the low refractive index pigment include silicic acid and salts thereof, barite powder, barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, talc, alumina white, magnesium carbonate, and the like. It is in the range of 1.8, and when the liquid composition is absorbed, good transparency is exhibited.
Examples of the silicic acid salt include aluminum silicate, aluminum potassium silicate, sodium aluminum silicate, aluminum calcium silicate, potassium silicate, calcium silicate, calcium sodium silicate, sodium silicate, magnesium silicate, and magnesium potassium silicate.
The particle size of the low refractive index pigment is not particularly limited, but 0.03 to 10.0 μm is preferably used.
Two or more of the low refractive index pigments can be used in combination.
In addition, silicic acid is mentioned as a low refractive index pigment used suitably.
The silicic acid may be silicic acid produced by a dry process, but silicic acid produced by a wet process (hereinafter referred to as wet process silicic acid) is particularly effective and satisfies practicality.
This point will be described below.
Silicic acid is produced as amorphous amorphous silicic acid, and according to its production method, a dry process using a gas phase reaction such as thermal decomposition of silicon halide such as silicon tetrachloride (hereinafter referred to as dry process silicic acid) In general, the wet process silicic acid is the most suitable for the purpose of functioning as the porous layer intended by the present invention, although the wet process uses a liquid phase reaction such as decomposition by acid such as sodium silicate. .
This is because the dry process silicic acid and the wet process silicic acid have different structures, and the dry process silicic acid forms a three-dimensional structure in which the silicic acid is closely bound, whereas the wet process silicic acid is a long molecule formed by condensation of silicic acid. It has a so-called two-dimensional structure part that forms an array.
Therefore, since the molecular structure becomes rough compared to the dry method silicic acid, when wet method silicic acid is applied to the porous layer, it is excellent in the diffused reflection of light in the dry state compared to the system using the dry method silicic acid, Therefore, it is guessed that the concealment property in a normal state becomes large.
In addition, since the porous layer of the present invention absorbs water, the wet process silicic acid has more hydroxyl groups present as silanol groups on the particle surface than the dry process silicic acid, and has a high degree of hydrophilicity. And is preferably used.
In addition, in order to adjust the concealability in the normal state of the porous layer and the transparency in the liquid absorption state, other general-purpose low-refractive-index pigments can be used in combination with the wet method silicic acid.

The wet process silicic acid in the porous layer depends on properties such as particle size, specific surface area, oil absorption, etc., but in order to satisfy both the concealing property in the normal state and the transparency in the liquid absorbing state, it is applied. preferably the amount is ^{1g / m 2 ~30g / m 2} , more ^{preferably 5g / m 2 ~20g / m 2} . If it is less than 1 g / m ² , it is difficult to obtain sufficient concealability in a normal state, and if it exceeds 30 g / m ² , it is difficult to obtain sufficient transparency during liquid absorption.
The particle size of the silicic acid is not particularly limited, but 0.03 to 10.0 μm is preferably used.
The silicic acid is dispersed in a vehicle containing a binder resin as a binder, applied to a base material, and then the volatile matter is dried to form a porous layer.
Examples of the binder resin include urethane resin, nylon resin, vinyl acetate resin, acrylic ester resin, acrylic ester copolymer resin, acrylic polyol resin, vinyl chloride-vinyl acetate copolymer resin, maleic resin, polyester resin, styrene. Resin, styrene copolymer resin, polyethylene resin, polycarbonate resin, epoxy resin, styrene-butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, methyl methacrylate-butadiene copolymer resin, butadiene resin, chloroprene resin, melamine resin, and the above Each resin emulsion, casein, starch, cellulose derivative, polyvinyl alcohol, urea resin, phenol resin and the like can be mentioned.
The mixing ratio of the silicic acid and these binder resins depends on the type and properties of silicic acid, but is preferably 0.5 to 2 parts by weight of binder resin solids, more preferably 1 part by weight of silicic acid. 0.8 to 1.5 parts by weight. When the binder resin solid content is less than 0.5 parts by weight with respect to 1 part by weight of silicic acid, it is difficult to obtain a practical film strength of the porous layer, and when it exceeds 2 parts by weight, The permeability of water into the porous layer is deteriorated.
Since the porous layer has a small mixing ratio of the binder resin to the colorant as compared with a conventionally known general coating film, it is difficult to obtain sufficient film strength. Therefore, in order to increase the scratch resistance, it is effective to use a nylon resin or a urethane resin among the binder resins.
Examples of the urethane resin include a polyester urethane resin, a polycarbonate urethane resin, and a polyether urethane resin, and two or more of them can be used in combination. In addition, a urethane emulsion resin in which the resin is emulsified and dispersed in water, or a colloid in which the resin is self-emulsified without the need for an emulsifier by an ionic group of the ionic urethane resin (urethane ionomer) itself and dissolved or dispersed in water. 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 in the present invention, an aqueous urethane-based resin, in particular, a urethane-based emulsion resin or a colloidally dispersed urethane-based resin is suitable. Used for.
The urethane resin can be used alone, but other binder resins can be used in combination depending on the type of support and the performance required for the coating. When a binder resin other than the urethane resin is used in combination, in order to obtain a practical film strength, it is preferable to contain 30% or more of the urethane resin in a solid content weight ratio in the binder resin of the porous layer.
In the binder resin, the crosslinkable resin can be further improved in film strength by adding an arbitrary crosslinking agent and crosslinking.
The binder resin has a large or small affinity with water. By combining these, the penetration time into the porous layer, the degree of penetration, and the slow speed of drying after the penetration can be adjusted. Furthermore, the said adjustment can be controlled by adding a dispersing agent suitably.

In the porous layer, conventionally known titanium dioxide-coated mica, iron oxide-titanium dioxide-coated mica, iron oxide-coated mica, guanine, sericite, basic lead carbonate, acidic lead arsenate, bismuth oxychloride, etc. The color change can be diversified by adding a metallic luster pigment or mixing general dyes and pigments, fluorescent dyes and fluorescent pigments.
In addition, conventionally known reversible thermochromic pigments that reversibly change color according to temperature change can be mixed, and the color can be changed depending on the environmental temperature or the water temperature to be adhered.
Furthermore, the color change can be further diversified by providing a colored layer in the upper layer, the lower layer, and / or the vicinity of the porous layer.
The porous layer and the colored layer are not limited to solid prints, and may be images (colored images) of characters, symbols, designs, and the like.
The porous layer and the colored layer are conventionally known means, for example, printing means such as screen printing, offset printing, gravure printing, coater, tampo printing, transfer, brush coating, spray coating, electrostatic coating, electrodeposition coating. It can be formed by flow coating, roller coating, dip coating or the like.

  In particular, when forming a colored image on a porous layer, it is an element as a learning material that can be traced and filled in with time by forming hiragana characters, alphabets, etc. with letters, or forming an appearance image of a clock Can be given in addition to the decorating effect, making it more useful.

The material of the plate-like foam used as the base material of the writing board is not particularly limited, and polyurethane, polyethylene, ethylene vinyl acetate, polyimide, polyester, synthetic rubber latex, natural rubber latex, synthetic rubber latex and natural rubber Examples thereof include foams made of a resin such as a latex mixture. The plate-like foam can be used alone or a plurality of sheets can be used together.
The foam has a hardness of 5 to 95, preferably 5 to 80.
If the hardness is less than 5, it is too soft and impairs practicality as a writing board, and it is difficult to satisfy the playability of forming a desired image from the porous layer. Furthermore, since it becomes easy to bend | fold, it is easy to produce a wrinkle in a porous layer, while impairing the appearance of goods, water enters easily along a wrinkle and it becomes difficult to form a stable image.
On the other hand, if the hardness exceeds 95, it is too hard to satisfy safety when used by an infant.
The hardness of the foam is measured according to JIS K 6301.

The tensile strength of the foam is 0.6 kg / cm ² or more, preferably 0.7 kg / cm ² or more.
If the tensile strength is less than 0.6 kg / cm ² , it can be easily torn off, so that the strength during use is impaired.
Furthermore, since the hardness and height of the mat are partially different due to tearing, the playability of forming a desired image from the porous layer is easily impaired. Specifically, when drawing on the porous layer using water, the writing board is likely to be recessed when reaching a portion having a different hardness or height, making it difficult to form a uniform drawn line.
The tensile strength of the foam is measured according to JIS K 6767.

The plate-like foam has a surface area of 100 to 8000 cm ² , preferably 100 to 2500 cm ² , and a thickness of 0.3 to 5 cm, preferably 0.5 to 3 cm. It is used from the practical side.

The foam may be directly provided with a porous layer, but a fabric such as a woven fabric, a knitted fabric, a braid, a nonwoven fabric, or a plastic film may be interposed between the foam and the porous layer.
Furthermore, a colored layer is preferably interposed between the fabric or plastic film and the porous layer.
This is because it is possible to diversify the color tone visually recognized in the liquid absorption state of the porous layer, and it is easy to form a colored layer of a pattern or a pattern, so that the added value can be increased. .

  The shape of the foam is not particularly limited, and is preferably a shape imitating a polygon such as a square, a rectangle, a triangle, a hexagon, a circle, an ellipse, a bowl, and other shapes such as animals, plants, and vehicles. Can be used. In particular, when a polygon is used, it is preferable to chamfer the acute angle portion of the apex or to have a curved surface in order to further improve safety.

The foam may be provided with a grip portion in order to improve carrying performance.
The grip portion can be easily provided by forming a hole in the vicinity of the outer peripheral portion of the foam, providing a handle-shaped portion, or connecting a handle of another member.
In particular, the hole is suitable because it is easy to form and does not cost.

Moreover, it is also possible to provide a connection part in the said foam so that a some writing board can be connected.
In addition to the configuration in which the surface fastener and the magnetic body are separately provided, the connection portion includes a configuration in which an uneven connection portion is provided on the side of the foam and the mutual unevenness is fitted.

As a method for adhering water to the reversible color-changing writing board, a method in which a hand or finger is wetted with water and brought into contact with the porous layer, a writing or applicator having a tip or a fiber pen at the tip, or A method of impregnating water into a sponge and bringing it into contact with the porous layer, a method of bringing a container containing water close to or in contact with the porous layer, and attaching water by deriving it from the inside of the container, and open cells or closed cells on the marking surface A method for impregnating water with a stamping tool having a foam adhered thereto and adhering it to a porous layer, a method for adhering water to a stamping tool with a rough marking surface of plastic or rubber, and bringing it into contact with the porous layer It is done.
In addition, as a method for bringing a container containing water close to or in contact with the porous layer and drawing out water from the inside of the container and attaching it, the fibrous body that contains water in the container and leads out the water in the container A method of applying water with a brush, a method of containing water in a container and a method of spraying water by providing a spray device, and pressing the water in the container like a syringe to eject water Methods and the like.
Examples of the means for adhering water include a writing or applicator, a sponge, a stamp, a spray device, and a syringe, and a reversible color-changing writing set can be obtained in combination with a reversible color-changing writing board.
In addition, as a preferable water adhering means, it is a writing instrument or applicator or a stamping instrument in which a plastic porous body or fiber processed body having continuous pores is applied as a pen tip member, and an arbitrary writing image or image can be easily formed. And practicality can be improved.
The plastic porous body or fiber processed body having continuous pores in the above may be any one that absorbs and discharges water in an appropriate amount, and has been conventionally used for continuous pores and fibers of general-purpose polyolefin-based, polyurethane-based, and other various plastics. Brush-like ones in which the fibers are focused, those obtained by resin processing or heat welding of fibers, felts, and non-woven fabrics. The shape and dimensions can be arbitrarily set according to the purpose.
Furthermore, a desired image can be easily formed by combining a stencil with the writing board or writing set.

Examples are shown below, but the present invention is not limited to the examples. In addition, the part in an Example shows a weight part and the hardness of the foamed material was measured with the spring type hardness tester (C type) according to JISK6301.
Example 1 (see FIG. 1)
On the surface of foam 2 made of black polyurethane (thickness 0.5 cm, foaming rate 30 times, hardness 10), 15 parts of wet process silicic acid [trade name: NIPSEAL E-200, manufactured by Nippon Silica Kogyo Co., Ltd.], urethane emulsion [ Product name: Hydran HW-930, manufactured by Dainippon Ink & Chemicals, Inc., solid content 50%] 30 parts, water 50 parts, silicone-based antifoaming agent 0.5 part, water-based ink thickener 3 parts, ethylene 1 part of glycol and 3 parts of blocked isocyanate cross-linking agent are uniformly mixed and stirred using a white screen printing ink, solid printed on a 100 mesh screen plate, dried and cured at 130 ° C. for 5 minutes, and porous. After forming the quality layer 3, the reversible color-changing writing board 1 was obtained by cutting into a rectangular shape having a length of 25 cm and a width of 30 cm (both top portions are formed in a curved shape).
The surface area of the porous layer provided on the surface of the reversible color-changing writing board 1 was 600 cm ² .
The tensile strength of the foamed material was 1.5 kg / m ² as a result of measurement according to JIS K 6767.
The reversible color-changing writing board 1 has a white porous layer 3 that is substantially white in the dry state. However, when water is attached, the porous layer 3 changes from a white opaque state to a colorless and transparent state by liquid absorption. The color tone of the lower foam material 2 is visually recognized, and the state is maintained in the liquid absorption state, but when the water is evaporated and dried, it changes to the original white state.

Example 2
A reversible color-changing writing set 1 obtained by combining the reversible color-changing writing board 1 obtained in Example 1 with a pen that can accommodate water in a shaft cylinder as a water adhering means and provided with a fiber processing pen body. Obtained.
When the reversible color-changing writing board 1 was drawn in the white porous layer 3 in a dry state with the pen, the porous layer 3 in that portion became transparent and a black writing image was visually recognized. The written image was retained when the porous layer 3 was in a liquid-absorbing state, and when dried, it returned to its original white color and became invisible, and this phenomenon could be repeated many times.

Example 3 (see FIG. 2)
15 parts of wet-process silicic acid [trade name: NIPSEAL E-200, manufactured by Nippon Silica Kogyo Co., Ltd.] on the entire surface of a pink non-woven fabric (Tetron 40%, cotton 60%) having a basis weight of 70 g / m ² as the fabric 4 Blue pigment 0.5 part, urethane emulsion [trade name: Hydran HW-930, manufactured by Dainippon Ink & Chemicals, Inc., solid content 50%] 30 parts, water 50 parts, silicone-based antifoaming agent 0.5 part, Using a blue screen printing ink obtained by uniformly mixing and stirring 3 parts of a thickener for water-based ink, 1 part of ethylene glycol, and 3 parts of a blocked isocyanate-based crosslinking agent, solid-printed on a 100 mesh screen plate, The porous layer 3 was formed by drying and curing at 130 ° C. for 5 minutes to obtain a reversibly discoloring fabric.
The reversible color-changing fabric is bonded to a foam 2 made of ethylene vinyl acetate (thickness 1 cm, expansion rate 10 times, hardness 25), and then cut into an elliptical shape having a short axis 30 cm and a long axis 40 cm, thereby reversible discoloration. A writing board 1 was obtained.
The surface area of the porous layer 3 provided on the surface of the reversible color-changing writing board 1 was 940 cm ² .
The tensile strength of the foamed material 2 was 10 Kg / cm ² as a result of measurement according to JIS K 6767.
When the reversible color-changing writing board 1 is in a dry state, a light blue porous layer 3 is visually recognized. However, when water is attached, the porous layer 3 changes from a light blue opaque state to a blue transparent state due to liquid absorption. The purple color due to the color mixture with the pink color of the lower fabric 4 is visually recognized and maintained in the liquid absorption state, but reversibly changes to the original light blue state by evaporating and drying the water. . This phenomenon could be repeated many times.

Example 4
A reversible color-changing writing set 1 obtained by combining the reversible color-changing writing board 1 obtained in Example 3 and a pen that is configured to be able to accommodate water in a shaft cylinder as a water adhering means and provided with a fiber processing pen body. Obtained.
When the reversible color-changing writing board 1 draws letters with the pen on the light blue porous layer 3 in a dry state, the porous layer 3 at that portion changes to a blue transparent state, and the lower pink fabric 4 A purple handwritten image due to the color mixture was recognized. The written image was retained when the porous layer 3 was in a liquid-absorbing state, and when dried, it returned to its original light blue color and became invisible, and this phenomenon could be repeated many times.

Example 5 (see FIG. 3)
The fabric 4 was solid-printed on a 180-mesh screen using a pink screen printing ink on the entire surface of a white nonwoven fabric (40% Tetron, 60% cotton) with a basis weight of 70 g / m ² at 100 ° C. The colored layer 5 was provided by drying and curing for 3 minutes.
Subsequently, 15 parts of wet process silicic acid [trade name: NIPSEAL E-200, manufactured by Nippon Silica Kogyo Co., Ltd.], 0.5 parts of green pigment, urethane emulsion [trade name: Hydran HW-930] are formed on the entire surface of the colored layer. , Manufactured by Dainippon Ink & Chemicals, Inc., solid content 50%] 30 parts, water 50 parts, silicone antifoam 0.5 parts, aqueous ink thickener 3 parts, ethylene glycol 1 part, blocked isocyanate Using a green screen printing ink obtained by uniformly mixing and stirring 3 parts of a cross-linking agent, solid printing is performed on a 100-mesh screen plate, followed by drying and curing at 130 ° C. for 5 minutes to form a porous layer 3. A reversible discolorable fabric was obtained.
The reversible color-changing fabric is bonded to a foam 2 made of ethylene vinyl acetate (thickness 1 cm, expansion rate 10 times, hardness 25), and then cut into an elliptical shape having a short axis 30 cm and a long axis 40 cm, thereby reversible discoloration. A writing board 1 was obtained.
The surface area of the porous layer 3 provided on the surface of the reversible color-changing writing board 1 was 940 cm ² .
The tensile strength of the foamed material 2 was 10 Kg / cm ² as a result of measurement according to JIS K 6767.
When the reversible color-changing writing board 1 is in a dry state, a light green porous layer 3 is visually recognized. However, when water is attached, the porous layer 3 changes from a light green opaque state to a green transparent state due to liquid absorption. The brown color due to the color mixture with the lower colored layer 5 is visually recognized and maintained in the liquid absorption state, but reversibly changes to the original light green state by evaporating and drying the water. This phenomenon could be repeated many times.

Example 6
A reversible color-changing writing set 1 obtained by combining the reversible color-changing writing board 1 obtained in Example 5 and a pen that is configured to be able to contain water in a shaft cylinder as a water adhering means and provided with a fiber processing pen body. Obtained.
When the reversible color-changing writing board 1 draws letters with the pen on the light green porous layer 3 in a dry state, the porous layer 3 in that portion changes to a green transparent state, and the lower colored layer 5 A brown handwritten image due to the color mixture was visually recognized. The written image was retained when the porous layer 3 was in a liquid-absorbing state, and when dried, it returned to its original light green color and became invisible, and this phenomenon could be repeated many times.

Example 7 (see FIG. 4)
The reversible color-changing writing board 1 provided with the porous layer 3 on both the front and back surfaces was obtained by providing the adhesive layers 9 between the back surfaces of the foamed materials and sticking the writing boards obtained in Example 5.
On both the front and back surfaces of the reversible color-changing writing board 1, a light green porous layer 3 is visually recognized in the dry state. However, when water is attached, the porous layer 3 is absorbed from the light green opaque state. It changes to a green transparent state, brown due to color mixture with the lower colored layer 5 is visually recognized, and the state is maintained in the liquid absorption state, but is reversible to the original light green state by evaporating and drying the water. Changes. This phenomenon could be repeated many times.

Example 8
A reversible color-changing writing set 1 obtained by combining the reversible color-changing writing board 1 obtained in Example 7 with a pen that can accommodate water as a water adhering means and that is provided with a fiber processing pen body. Obtained.
When both the front and back surfaces of the reversible color-changing writing board 1 are in a dry state and a character is drawn on the light green porous layer 3 with the pen, the porous layer 3 in that portion changes to a green transparent state, The brown writing image by color mixture with the colored layer 5 was visually recognized. The written image was retained when the porous layer 3 was in a liquid-absorbing state, and when dried, it returned to its original light green color and became invisible, and this phenomenon could be repeated many times.

Example 9 (see FIGS. 5 and 6)
On the entire surface of a pink non-woven fabric (100% cotton) having a basis weight of 80 g / m ² as fabric 4, 15 parts of wet-process silicic acid [trade name: NIPSEAL E-200, manufactured by Nippon Silica Kogyo Co., Ltd.], urethane emulsion [commodity Name: Hydran HW-930, manufactured by Dainippon Ink & Chemicals, Inc., solid content 50%] 30 parts, water 50 parts, silicone antifoam 0.5 parts, aqueous ink thickener 3 parts, ethylene glycol 1 part and 3 parts of blocked isocyanate cross-linking agent are mixed and stirred uniformly, using a white screen printing ink, solid printed on a 100 mesh screen plate, dried and cured at 130 ° C. for 5 minutes to be porous Layer 3 was formed to obtain a reversible color-changing fabric that changed from white to pink by absorbing water.
Further, a colored image 6 (letter alphabet) was formed on the porous layer 3 of the reversible color-changing fabric using blue ink.
The reversible color-changing fabric was pasted to ethylene vinyl acetate foam 2 (thickness 1.5 cm, expansion rate 20 times, hardness 15), and then cut into an elliptical shape having a short axis of 30 cm and a long axis of 40 cm. A color-changing writing board 1 was obtained. Furthermore, the hole part used as the holding part 7 was formed in the upper outer periphery vicinity of the reversible color-changeable writing board 1 obtained.
The surface area of the porous layer 3 provided on the surface of the reversible color-changing writing board 1 was 900 cm ² .
The tensile strength of the foamed material 2 was 7.0 kg / cm ² as a result of measurement according to JIS K 6767.
When the reversible color changing writing board 1 is in a dry state, a blue colored image 6 is visually recognized on the white porous layer 3. However, when water is attached, the porous layer 3 is changed from a white opaque state to a transparent state by liquid absorption. It changes, and the pink color of the lower fabric 4 is visually recognized, and the state is maintained in the liquid absorption state, but reversibly changes to the original white state by evaporating and drying the water. This phenomenon could be repeated many times.
Moreover, the carrying part is improved by the holding part 7, and it can be easily held with one hand.

Example 10
A reversible color-changing writing set obtained by combining the reversible color-changing writing board 1 obtained in Example 9 with a pen that is configured to be able to contain water in a shaft cylinder as a water adhering means and provided with a fiber processing pen body. Obtained.
When the reversible color-changing writing board 1 draws letters with the pen on the white porous layer 3 in a dry state, the porous layer 3 at that portion changes to a transparent state, and the pink color of the underlying fabric 4 A written image was visible. The written image was retained when the porous layer 3 was in a liquid-absorbing state, and when dried, it returned to its original white color and became invisible, and this phenomenon could be repeated many times.
In addition, by tracing the colored image 6 (extracted character portion) with the pen, each alphabet is obtained with a pink handwriting, and an element as a learning material is provided.

Example 11 (see FIG. 2)
On the entire surface of a transparent polyethylene terephthalate plastic film 7 having a thickness of 16 μm, 15 parts of wet-method silicic acid [trade name: Nipseal E-200, manufactured by Nippon Silica Kogyo Co., Ltd.], urethane emulsion [trade name: Hydran AP-10, Dainippon Ink & Chemicals, Inc., solid content 30%] 50 parts, water 50 parts, silicone-based antifoaming agent 0.5 part, water-based ink thickener 3 parts, ethylene glycol 1 part, blocked isocyanate-based crosslinking Using a white screen printing ink that is uniformly mixed and stirred with 3 parts of the agent, solid printing is performed on a 100-mesh screen plate, followed by drying and curing at 130 ° C. for 5 minutes to form a porous layer 3 and reversible. A discoloring film was obtained.
The reversible color-changing film is attached to a green polyethylene foam material 2 (thickness 2 cm, expansion rate 15 times, hardness 15), and then cut into an elliptical shape with a short axis 30 cm and a long axis 40 cm. A plate 1 was obtained. Furthermore, the hole part used as a holding part was formed in the upper outer periphery vicinity of the reversible color-changeable writing board 1 obtained.
The surface area of the porous layer 3 provided on the surface of the reversible color-changing writing board 1 was 900 cm ² .
The tensile strength of the foam material 2 was 4.0 kg / cm ² as a result of measurement according to JIS K 6767.
When the reversible color-changing writing board 1 is in a dry state, a white porous layer 3 is visually recognized on the entire surface. However, when water is attached, the porous layer 3 changes from a white opaque state to a transparent state due to liquid absorption. Although the green color of the foam material 2 is visually recognized and maintained in the liquid absorption state, it reversibly changes to the original white state by evaporating and drying the water. This phenomenon could be repeated many times.

Example 12
A reversible color-changing writing set was obtained by combining the reversible color-changing writing board 1 obtained in Example 11 and a stamp tool provided with a felt material impregnated with a liquid as a water adhering means.
When the reversible color-changing writing board 1 was imprinted on the white porous layer 3 in a dry state, the porous layer 3 in that portion was changed to a transparent state, and the green imprint of the lower foam material 2 was visually recognized. . The imprint was retained when the porous layer 3 was in a liquid-absorbing state, and when dried, it returned to its original white color and became invisible, and this phenomenon could be repeated many times.

Example 13 (see FIGS. 6 and 7)
On the entire surface of a pink non-woven fabric (100% cotton) having a basis weight of 80 g / m ² as fabric 4, 15 parts of wet-process silicic acid [trade name: NIPSEAL E-200, manufactured by Nippon Silica Kogyo Co., Ltd.], urethane emulsion [commodity Name: Hydran HW-930, manufactured by Dainippon Ink & Chemicals, Inc., solid content 50%] 30 parts, water 50 parts, silicone antifoam 0.5 parts, aqueous ink thickener 3 parts, ethylene glycol 1 part and 3 parts of blocked isocyanate cross-linking agent are mixed and stirred uniformly, using a white screen printing ink, solid printed on a 100 mesh screen plate, dried and cured at 130 ° C. for 5 minutes to be porous Layer 3 was formed to obtain a reversible color-changing fabric that changed from white to pink by absorbing water. Further, a colored image 6 (letter alphabet) was formed on the porous layer 3 of the reversible color-changing fabric using a blue ink (reversible color-changing fabric A).
Next, a wet process silicic acid [trade name: NIPSEAL E-200, manufactured by Nippon Silica Kogyo Co., Ltd.] is applied on the entire surface of a pink nonwoven fabric (Tetron 40%, cotton 60%) having a basis weight of 70 g / m ² as the fabric 4 ′. 15 parts, blue pigment 0.5 parts, urethane emulsion [trade name: Hydran HW-930, manufactured by Dainippon Ink & Chemicals, Inc., solid content 50%] 30 parts, water 50 parts, silicone-based antifoaming agent 0 .5 parts, 3 parts of a thickener for water-based ink, 1 part of ethylene glycol, 3 parts of a blocked isocyanate-based cross-linking agent are mixed uniformly and stirred, using a blue screen printing ink, in a 100 mesh screen plate Solid printing, drying and curing at 130 ° C. for 5 minutes to form a porous layer 3 ′, and a reversible color-changing fabric that changed from a light blue opaque state to a blue transparent state by absorbing water was obtained. Further, on the porous layer 3 'of the reversible color-changing fabric, a colored image 6' (clock image without long hands and short hands) was formed using a yellow ink (reversible color-changing fabric B).
The reversible color-changing fabrics A and B are attached to both front and back surfaces of a foam material 2 (thickness 1.5 cm, expansion rate 20 times, hardness 15) made of ethylene vinyl acetate, and then an ellipse having a short axis 30 cm and a long axis 40 cm. The reversible color-changing writing board 1 was obtained by cutting into a shape. Furthermore, the hole part used as the holding part 7 was formed in the upper outer periphery vicinity of the reversible color-changeable writing board 1 obtained.
The surface area of the porous layer 3 provided on the reversible color change writing board 1 was 900 cm ² on both the front surface (reversible color change fabric A side) and the back surface (reversible color change fabric B side).
The tensile strength of the foamed material 2 was 7.0 kg / cm ² as a result of measurement according to JIS K 6767.
When the surface of the reversible color-changing writing board 1 is in a dry state, a blue colored image 6 is visually recognized on the white porous layer 3. However, when water is attached, the porous layer 3 is removed from the white opaque state by liquid absorption. It changes to a transparent state, the pink color of the lower fabric 4 is visually recognized, and the state is maintained in the liquid absorption state, but reversibly changes to the original white state by evaporating and drying water. Met. In addition, on the back surface, a porous layer 3 ′ having a light blue color is visually recognized in the dry state. However, when water is attached, the porous layer 3 ′ changes from a light blue opaque state to a blue transparent state by liquid absorption. The purple color due to the color mixture with the pink color of the lower fabric 4 'is visually recognized and maintained in the liquid absorption state, but reversibly changes to the original light blue state by evaporating and drying the water. It was a thing. These phenomena could be repeated many times.
Moreover, the carrying part is improved by the holding part 7, and it can be easily held with one hand.

Example 14
A reversible color-changing writing set obtained by combining the reversible color-changing writing board 1 obtained in Example 13 with a pen that can accommodate water in a shaft cylinder as a water adhering means and provided with a fiber processing pen body. Obtained.
On the surface of the reversible color-changing writing board 1, when letters are drawn on the white porous layer 3 in a dry state with the pen, the porous layer 3 in that portion is changed to a transparent state, and the lower fabric 4 The pink writing image of was visible. The written image was retained when the porous layer 3 was in a liquid-absorbing state, and when dried, it returned to its original white color and became invisible, and this phenomenon could be repeated many times. Furthermore, by tracing the colored image 6 (extracted character portion) with the pen, each alphabet is obtained with a pink handwriting, and has an element as a learning material.
On the back surface, when letters are drawn on the light blue porous layer 3 ′ with the pen in a dry state, the porous layer 3 ′ in that portion changes to a blue transparent state, and the underlying pink fabric 4 ′. A purple handwritten image due to the color mixture was recognized. The written image was retained when the porous layer 3 ′ was in a liquid-absorbing state, and when dried, it returned to its original light blue color and became invisible, and this phenomenon could be repeated many times. Furthermore, by drawing the long and short hands indicating the desired time on the colored image 6 '(the image of the clock without the long and short hands) with the pen, each hand is obtained with a purple handwriting, which is an element as a learning material. It became to be equipped with.

It is a longitudinal cross-sectional explanatory drawing of the reversible color-change writing board of this invention. It is a longitudinal cross-sectional explanatory drawing of another reversible color-change writing board of this invention. It is a longitudinal cross-sectional explanatory drawing of another reversible color-change writing board of this invention. It is a longitudinal cross-sectional explanatory drawing of another reversible color-change writing board of this invention. It is a longitudinal cross-sectional explanatory drawing of another reversible color-change writing board of this invention. It is an external view of the reversible color-change writing board of FIG. It is a longitudinal cross-sectional explanatory drawing of another reversible color-change writing board of this invention.

Explanation of symbols

1 Reversible color-changing writing board 2 Foam (plate-like foam)
3, 3 'porous layer 4, 4' fabric 5 colored layer 6, 6 'colored image 7 gripping part 8 plastic film 9 adhesive layer

Claims (11)

  On the surface of the plate-like foam having a hardness of 5 to 95, a porous layer having a low refractive index pigment fixed to a binder resin in a dispersed state and having different transparency in a liquid absorption state and a non-liquid absorption state is provided. Reversible color-changing writing board.   2. A porous layer having a low refractive index pigment fixed to a binder resin in a dispersed state and having a different transparency in a liquid-absorbing state and a non-liquid-absorbing state is provided on the back surface of the plate-like foam. Reversible color-changing writing board. Reversibly variable color writing board according to claim 1 or 2 tensile strength of the foam is 0.6 Kg / m ² or more. Reversibly variable color writing board according to any one of claims 1 to 3 surface area of the porous layer provided on said foam is 100~8000cm ^2.   The reversible color-changing writing board according to any one of claims 1 to 4, wherein a colored image is formed on the porous layer.   The reversible color-changing writing board according to any one of claims 1 to 5, wherein a cloth or a plastic film is interposed between the plate-like foam and the porous layer.   The reversible color-changing writing board according to claim 6, wherein the fabric is selected from a woven fabric, a knitted fabric, a braided fabric, and a nonwoven fabric.   The reversible color-changing writing board according to claim 6 or 7, wherein a colored layer is interposed between the fabric or plastic film and the porous layer.   The reversible color-changing writing board according to any one of claims 1 to 8, wherein a grip portion is provided on the foam.   A reversible color-changing writing set comprising the reversible color-changing writing board according to claim 1 and water adhering means.   The reversible color-changing writing set according to claim 10, wherein the water adhering means is selected from any one of a writing tool, an applicator, or a stamp tool in which a plastic porous body or a fiber processed body having continuous pores is applied as a pen tip member.

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