JPH08244397A - Thermally discoloring material to be written - Google Patents

Abstract

PURPOSE: To provide a thermally discoloring material to be written in which an image can be easily color developed or erased by using hot water of a bathtub, ice piece or cold water in a bathroom or near the bathtub through the year, which can be simply used and in which the image exposing or erasing state can be maintained. CONSTITUTION: A thermally discoloring material to be written exposes a thermally discoloring image or discolors to an invisible state by discoloring means via heat medium such as ice piece, cold water or warm water by the use near a bathroom or a bathtub, and is colored with coloring material containing color storage thermal discoloring pigment to be discolored in large hysteresis characteristics in the relation between the temperature and the color density with arbitrary temperature selected from the temperature ranges of 16 to 25 deg.C of temperature T2 and 30 to 37 deg.C at the temperature T4 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive discolorable writing material. More specifically, the present invention relates to a temperature-sensitive discolorable writing material in which an image appears on the writing object or the image becomes invisible due to application of cold heat or a heating medium in or near the bath.

[0002]

2. Description of the Related Art Conventionally, a reversible thermosensitive recording material consisting of a base material coated with a thermochromic material is used for a bath in which a heating or cooling medium such as bath water or water is applied to develop and erase a written image. A writing plate is disclosed (Japanese Patent Laid-Open No. 59-120492). The thermochromic material applied to the bath writing board shows a large hysteresis characteristic due to a temperature change, and exhibits a reversible change of coloring-decoloring, and even after the application of heating or cooling / heating medium is removed, or Any of the decolored states can be retained in an alternating and reversible manner.

[0003]

The above-mentioned conventional bath writing plate is capable of maintaining a state in which an image is colored or decolored at room temperature or in a specific temperature range, even when the temperature is high or low. The hot water temperature and the hot water temperature vary depending on the time or the season, so that the image may appear on the writing material, the image may be erased, and the image may be maintained in a decolorized state throughout the year. Will be difficult. Therefore, the discoloration temperature (T ₄ ) at the time of erasing is set to a temperature higher than the temperature in the bathroom or in the vicinity of the bath and lower than the hot water temperature so that the image can be erased by the hot water and the state is maintained. Further, the discoloration temperature (T ₂ ) at the time of coloring can be set to a temperature lower than the temperature in the bathroom or in the vicinity of the bath, and the image can be displayed with ice pieces or cold water and the state can be maintained. As a result of diligent studies to solve the drawbacks of the conventional writing plate for a bath by using a thermochromic material having a set discoloration temperature, the temperature in the bathroom at the time of bathing was about 20 ° C throughout the year.
-30 ° C, the temperature in the vicinity of the bath is approximately 25 ° C to 30 ° C, and by paying attention to the relatively narrow temperature range, by specifying the color change temperature of the thermochromic material, it is possible to determine whether the temperature is high or low or the season is cold. The present invention provides a thermosensitive discolorable writing material which can easily develop and decolor an image by using ice pieces, cold water or hot water without being affected by the influence of the above.

[0004]

The present invention is used in a bathroom or in the vicinity of a bath, and a thermochromic image is revealed or invisible by a color changing means via cold heat or a heat medium such as ice pieces, cold water, or hot water. A thermosensitive discolorable writing material that discolors into
The temperature-sensitive color-changing writing object is colored with a color material containing a color memory-type temperature-sensitive color-changing pigment that exhibits a large hysteresis characteristic in the relationship of temperature-color density, and the temperature-sensitive color-changing pigment is In the process in which the temperature of the pigment rises in the first hue state, the first hue starts to change color when reaching the temperature T ₃ , and becomes the second hue completely in the temperature range of the second temperature T ₄ or higher, in the process of temperature pigment is in the second color state is lowered, the the second reaching the first temperature T ₂ lower than the temperature T ₄ second color begins to discolor, lower than the first temperature T ₂ The first hue is completely formed in the temperature range of the temperature T ₁ or less, and the first hue and the second hue are sharable in the temperature range between the temperatures T ₂ and T ₃ and exhibit a hysteresis characteristic. a pigment, wherein said first temperature T ₂ is 16 ° C. to 25 ° C., and a second temperature ₄ is a thermochromic the writing body requirements and characterized by having an optional temperature selected from a temperature range of 30 ° C. to 37 ° C.. Further, the first temperature T ₂ has an arbitrary temperature selected from the temperature range of 16 ° C. to 20 ° C. and the second temperature T ₄ of 33 ° C. to 37 ° C. The temperature sensitive discolorable writing material is required.

As a color material containing the above-mentioned color-memory sensitizing thermochromic pigment, for example, Japanese Patent Publication No. 4-1 proposed by the present applicant has been proposed.
The system described in Japanese Patent No. 7154, which is colored with a thermochromic material containing a color-memory thermochromic dye that exhibits large hysteresis characteristics and is discolored, is effective. The dye exhibits a large hysteresis width (ΔH) and changes color.
That is, the shape of the curve plotting the change of the coloring density due to the temperature change is such that the temperature rises from the lower temperature side than the discoloration temperature range and the lower temperature decreases from the higher temperature side than the discoloration temperature range. It is a type that changes color by following a very different route. In addition, a color material containing the color-memory thermochromic pigment, in order to improve the sensitivity and sensitivity of color change,
A microcapsule pigment encapsulated in a microcapsule is preferably used.

The hysteresis characteristics in the color density-temperature curve of the thermochromic material will be described below with reference to the graph of FIG. In FIG. 1, the vertical axis represents color density and the horizontal axis represents temperature. The change in color density due to the temperature change progresses along the arrow. Point A (temperature T ₁ ) in the graph is a point at which the color material is completely colored at a temperature below this,
Point B (temperature T ₃ ) is a point where substantial color erasing starts in the process of temperature rise, and point C (temperature T ₄ ) is a point where the color is completely erased at a temperature higher than this. Yes, point D (temperature T ₂ ) is the point where substantial color development starts in the process of temperature decrease, and the discoloration temperature range is the temperature range between T ₁ and T ₄ , especially the colored and colorless states. The temperature range between T ₂ and T ₃ where both phases can coexist and the difference in color density is large is referred to as a substantial discoloration temperature range (two-color holding temperature range). Also, the line segment E
The length of F is a temperature width (hysteresis width ΔH) indicating the degree of hysteresis.

The relationship between the discoloring temperature of the color material containing the color-memory temperature-sensitive discoloring pigment, the temperature in the bathroom or near the bath, and the hot water temperature will be described below with reference to FIGS. 2 and 3. In the writing material, it is practically preferable to specify the temperature at which the image starts to develop color and the temperature at which the image is completely erased. In FIG. 2, the temperature range of the first temperature T ₂ or higher and the second temperature T ₄ or lower includes the temperature range (20 ° C. to 30 ° C.) in the bathroom at the time of bathing, so that the image is colored or decolored. It is possible to keep the state that it did. In addition, the temperature near the bathtub such as the wall surface above the bathtub and the wall surface around the bathtub when the bathtub is filled with hot water is about 2
Since it is 5 ° C. to 30 ° C., T ₂ is preferably 25 ° C. or lower and T ₄ is preferably 30 ° C. or higher.

The second temperature T ₄ is set to be higher than the temperature in the bathroom and in the vicinity of the bathtub and lower than the hot water temperature so that the image can be erased by the hot water in the bathtub or the like. In addition, the state can be maintained at the temperature in the bathroom or near the bath. Specifically, since the hot water in the bathtub is in the range of approximately 37 ° C to 42 ° C, it is set to 30 ° C to 37 ° C, preferably 33 ° C to 37 ° C which is slightly higher than the temperature in the bathroom and in the vicinity of the bathtub ( (See FIG. 3).

Further, the first temperature T ₂ is set lower than the temperature in the bathroom or in the vicinity of the bathtub and higher than the ice pieces or cold water, so that the image is colored by the ice pieces or cold water. In addition, the state can be maintained at the temperature in the bathroom or near the bathtub. Specifically, it is set in the range of 16 ° C. to 25 ° C., preferably 20 ° C. to 25 ° C. (see FIG. 3). When the minimum temperature T ₂ is set to 16 ° C. or lower, even if the image can be colored with cold water at a temperature lower than that, sufficient handwriting density cannot be obtained, and it is difficult for the image to appear at a high writing speed.

The color memorizing thermochromic pigment is dispersed in a medium containing a binder which is a film forming material, applied as a coloring material such as ink or paint, and formed on the surface of a support to form a writing object. To do. As the printed matter in which the thermochromic material is applied on the support, the color memorable printed matter described in JP-B-6-59746 can be used. Alternatively, a thermochromic material encapsulated in microcapsules may be melt-blended integrally with a thermoplastic resin to form a film or sheet. Further, it may be formed by spraying a spray ink in which the color-memory color-changing color-changing pigment is dispersed on a support.

The support to which the color material is applied is all effective as long as it is a substrate having printability. For example, paper, synthetic paper, cloth such as knitted fabric, flocked or raised fabric, non-woven fabric, synthetic leather. , Leather, plastic, glass, porcelain, metal,
Wood, stone, etc. are used. The shape is preferably flat, but may be uneven. Also, the support may be a toy in the shape of a car, an airplane, a train, a ship, or a stuffed animal.

The color material applied to the support is not limited to a color material containing a color-memory color-changing color-changing pigment, but a conventional general non-color-changing ink may be used to form a color containing the color-memory color-changing color-changing pigment. It is possible to diversify the designs, colors, etc. by arranging them in parallel with the material, overprinting, etc.

When a color material containing a color-memory thermochromic pigment is laminated on a support, the laminate is formed by a conventionally known method, for example, screen printing, offset printing, gravure printing, coater or tampo printing. , Printing means such as transfer,
It can be carried out by means of brush coating, spray coating, electrostatic coating, electrodeposition coating, flow coating, roller coating, dip coating and the like. Further, it can also be made into a film sheet and stuck together.

Furthermore, the actual application filed by the applicant earlier is:
Thickness of 20 μm to 0.5 mm described in Japanese Patent No. 85691.
A synthetic paper having a thickness of preferably 40 μm to 0.3 mm, a polyester film and other plastic films are provided underneath, and a plastic porous body such as polyurethane and polyethylene having a thickness of 0.5 mm to 10 mm, urethane rubber, styrene-butadiene rubber, When a rubber-based material such as fluorine-based rubber, ethylene propylene rubber, or silicone rubber, or an elastic material such as felt or non-woven fabric is fixed and formed, when a heating or cooling discoloration tool is used, it has an elastic writing feel or a writing tip abutment. It is effective as a support because it provides close contact with the writing tip by forming a resilient depression having a writing tip shape corresponding to the writing pressure.

Examples of the heating or cooling discoloring tool include those having a tapered tip and a writing form, or those having a stamp form in which an image of a character, a pattern, a pattern or the like is formed on the tip, such as hot water. A heating pen filled with
As disclosed in JP-A-06299), a cooling pen or the like filled with a coolant such as cold water or ice pieces can be used as the cooling discoloration tool. Further, a sponge impregnated with hot water, cold water, etc. can also be used as a color changing tool. Specifically, cold water is impregnated into a sponge of an arbitrary shape and brought into contact with the writing object,
It can be used as a stamp for displaying an image of an arbitrary shape, or as an erasing tool for erasing an image on a writing object by impregnating it with hot water in a bath.

[0016]

When the temperature-sensitive color-changing writing material constructed as described above is used in the bathroom or in the vicinity of the bathtub, the color material containing the color-memory temperature-sensitive color-changing pigment is exposed to ice chips or cold water in a decolored state. When brought into contact with the cursive body surface, the coloring material develops color and an image appears. The image is held in the bathroom or in the temperature range near the bath. Furthermore, when the hot water in the bathtub is brought into contact with the portion where the image on the temperature-sensitive discolorable writing material appears, the image disappears and becomes invisible. Further, the appearance in which the image disappears is retained in the temperature range in the bathroom or near the bath. Note that this aspect can be repeated.

When the color material containing the color memorizing temperature-sensitive color-changing pigment is in a colored state, when the hot water in the bath is brought into contact with the color material, the color material is erased and a blank image appears. The image is held in the bathroom or in the temperature range near the bathtub. Furthermore, when ice pieces or cold water is brought into contact with the portion of the thermosensitive discolorable writing material on which the bleeding image appears, the coloring material is colored and the bleeding image becomes invisible. Further, the aspect is maintained in the temperature range in the bathroom or near the bath. Note that this aspect can be repeated.

[0018]

【Example】

Example 1 80 μm thick white synthetic paper coated with an adhesive
A polyethylene foam having a thickness of mm was attached to form a support. On the upper surface of the support formed as described above, a color-memory thermochromic pigment [blue ← → colorless (D point 24 ° C, C point 34 ° C)
Is printed in a ethylene-vinyl acetate copolymer resin emulsion (using Japanese Patent Publication No. 4-17154), and after the color material is dried, an overcoat clear ink (solvent-type alkyd resin is used as a binder). Was used as a protective layer.

When the temperature-sensitive discoloring writing material formed as described above is suspended from the wall surface of the bathroom near the bath at 27 ° C. and used, the entire surface is soaked in hot water (38 ° C.) in the bath to memorize the color. The sensitizing thermochromic pigment disappears and the entire surface is white. The appearance that the entire surface was white was retained on the wall surface of the bathroom. When writing was performed with a cooling pen having a writing tip temperature of 13 ° C., which was filled with cold water, on the temperature-sensitive color-changing writing object exhibiting white, the color-memory color-changing color-changing pigment was colored to obtain blue handwriting. It was The blue handwriting was retained on the bathroom wall. Further, when the thermochromic writing material on which the handwriting was drawn was immersed again in the hot water of the bath, it returned to a white state and could be used repeatedly.

Example 2 A white synthetic paper having a thickness of 80 μm was coated with an adhesive to prepare 1
A polyethylene foam having a thickness of mm was attached to form a support. On the upper surface of the support formed as described above, a color-memory-type thermochromic pigment [green ← → colorless (D point 25 ° C., C point 37 ° C.)
Is printed in an ethylene-vinyl acetate-based copolymer resin emulsion (using Japanese Patent Publication No. 4-17154), and after the color material is dried, an overcoat clear ink (solvent-based acrylic resin is used as a binder). Was used as a protective layer.

When the temperature-sensitive discoloring writing material formed as described above is used slightly above the bath surface in the vicinity of the bath at 29 ° C., the entire surface is soaked in cold water at 18 ° C. The color-changing pigment develops color, and the entire surface is green. The appearance that the entire surface was green was retained near the bath. The temperature-sensitive discolorable writing material exhibiting the green color was filled with hot water in a bathtub,
When writing with a heating pen having a writing tip temperature of 41 ° C., the color memory memorable thermochromic pigment was decolored and white handwriting was obtained. The white handwriting was retained near the bath. or,
When the thermochromic writing material on which the handwriting was drawn was immersed again in cold water, the entire surface returned to a green state and could be used repeatedly.

Example 3 A white polyester film having a thickness of 50 μm was coated with an adhesive, and a polyethylene foam having a thickness of 2 mm was attached thereto to form a support. A yellow non-thermochromic ink is printed on the upper surface of the support formed as described above, and on the upper surface, a color-memory thermosensitive pigment (blue ← → colorless (D point 16 ° C.,
A color material (using Japanese Patent Publication No. 4-17154) in which ethylene (C point 31 ° C.) is dispersed in an ethylene-vinyl acetate copolymer resin emulsion is printed, and after the color material is dried, an overcoat clear ink (solvent) is used. Type alkyd resin was used as a binder) to form a protective layer.

The temperature-sensitive discoloring writing material formed as described above is used in a bathroom at 21 ° C. (the temperature near the bath is 2
In the case of 5 ° C.), when the entire surface is immersed in hot water (40 ° C.) in the bathtub, the color memorizing temperature-sensitive color-changing pigment is decolored and the whole surface becomes yellow due to the non-thermochromic ink. The appearance that the entire surface was yellow was retained in the bathroom. When writing with a cooling pen having a writing tip temperature of 5 ° C., which was filled with ice pieces, the temperature-sensitive color-changing pigment exhibiting a yellow color, the color-memory color-changing color-changing pigment was colored, and the non-heat Green handwriting was obtained on the yellow background of the tarnishing ink. The green handwriting was retained in the bathroom. When the thermochromic writing material on which the above-mentioned handwriting was drawn was re-immersed in the hot water of the bathtub, it returned to a yellow state and could be used repeatedly.

Example 4 A white polyester film having a thickness of 50 μm was coated with an adhesive, and a polyethylene foam having a thickness of 2 mm was attached thereto to form a support. Color memory-type thermochromic pigment [blue ← → colorless (D point 19 ° C, C point 32 ° C), green ← → colorless (D point 19 ° C, C point 32 ° C), orange ← → colorless (D point 19)
℃, C point 32 ℃), pink ← → colorless (D point 19 ℃, C point 3
2 ° C.)] is dispersed in an ethylene-vinyl acetate copolymer resin emulsion (Japanese Patent Publication No. 4-17154).
(Japanese Patent Application Laid-Open Publication No. Hei 10 (1999)), regular hexagons having different color tones are printed adjacent to each other to form a honeycomb pattern. After the color material was dried, overcoat clear ink (using a solvent-type acrylic resin as a binder) was printed to form a protective layer.

The temperature-sensitive discoloring writing material formed as described above is used in a bathroom at 24 ° C. (the temperature near the bath is 2
In the case of 8 ° C.), when the entire surface is immersed in hot water (37 ° C.) in the bath, the color-memory color-changing thermochromic pigment is decolored and the entire surface becomes white.
The appearance that the entire surface was white was retained in the bathroom.
When the temperature-sensitive discolorable writing material exhibiting the white color was brought into contact with a stamp-shaped cooling tool filled with ice pieces and water (10 ° C.) and having a tip with a heart pattern, the coloring material developed a color,
A heart-shaped imprint of blue, green, orange, and pink was obtained. The heart-shaped imprint was retained in the bathroom.
When the thermochromic writing material on which the heart-shaped printed image was drawn was immersed in hot water in the bathtub again, it returned to a white state and could be used repeatedly.

[0026]

EFFECTS OF THE INVENTION The temperature-sensitive discolorable writing material of the present invention is set to a temperature higher than the temperature in the bathroom and lower than the hot water temperature at the time of discoloring (T ₄ ), and The image can be erased and the state can be maintained in the bathroom. Furthermore, the discoloration temperature (T ₂ ) at the time of coloring is set to a temperature lower than the temperature in the bathroom or in the vicinity of the bathtub, and ice pieces or cold water is set. By using a color-memory thermochromic pigment that specifies the discoloration temperature so that the image can be displayed and maintained in that state, the temperature can be kept low throughout the year and the seasonal cold Can be used. or,
An image can be easily developed and decolored by using hot water in a bathtub and ice pieces or cold water, and a simple and easy-to-use thermosensitive discolorable writing material can be provided. Still, since the state in which the image appears or is erased can be maintained in the bathroom or in the vicinity of the bath, it is suitable as a writing material, and a temperature-sensitive discoloring writing material for practical use is provided. You can

[Brief description of drawings]

FIG. 1 is a graph showing a color change state of a color material containing a color-memory color-changing color change pigment used in the present invention due to a temperature change.

FIG. 2 is a related explanatory diagram of temperature factors of the present invention.

FIG. 3 is a related explanatory view showing a suitable temperature as a temperature factor of the present invention.

Claims (2)

[Claims] 1. An ice piece for use in a bathroom or near a bathtub,
Cold water, or a thermochromic image by a color changing means via cold heat or a heat medium such as hot water, or a thermosensitive discolorable writing material that discolors to an invisible state, wherein the thermosensitive discolorable writing material is Temperature-color density is colored with a color material containing a color memory memorizing temperature-sensitive color-changing pigment exhibiting a large hysteresis characteristic in the relationship of color density, and the temperature-sensitive color-changing pigment has the pigment in the first hue state. In the process of increasing the temperature, the temperature T
_When it reaches ₃ , the first hue starts to change color, becomes the second hue completely in the temperature range of the second temperature T ₄ or higher, and the pigment is in the second hue state. When the reached the first temperature T ₂ lower than the temperature T ₄ second color begins to discolor, become completely first color at a first low temperature T ₁ of the following temperature range than temperature T _2, the temperature T ₂ And a temperature T ₃ in a temperature range between the first hue and the second hue, the pigment exhibiting hysteresis characteristics such that both the first hue and the second hue can be shared, wherein the first temperature T ₂ is 16 ° C. to 25 ° C. ° C., and the second thermochromic the cursive temperature T ₄ is characterized by comprising a any temperature selected from a temperature range of 30 ° C. to 37 ° C. for. 2. The first temperature T ₂ is 16 ° C. to 20 ° C.
2. The thermosensitive color-changing writing according to claim 1, which is a color-memory thermochromic pigment having an arbitrary temperature selected from the temperature range of 33 ° C. to 37 ° C. and a second temperature T _4. body.