JPH10193871A - Thermally discoloring laminated sheet and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermally discoloring laminated sheet which scarcely generates wrinkle due to being by sequentially laminating a reversibly thermally discoloring layer and an urethane resin layer on a support in a thermally discoloring laminated layer sheet, and setting a modulus of specific ratio of the resin layer to a specific pressure. SOLUTION: After urethane resin release sheet is coated with urethane resin solution, it is dried to form an urethane resin layer 5. After the layer 5 is coated with reversibly thermally discoloring ink, it is dried to form a reversibly thermally discoloring layer 4. Then, after the layer 4 is coated with urethane resin solution, it is dried to form an adhesive layer 3. After a polyester raised blanket is laminated as a support 2 on the layer 3, release sheet is released to obtain a thermally discoloring laminated sheet 1. Here, 100% modulus of the layer 5 is 50 to 300kg/cm<2> or preferably 75 to 200kg/cm<2> . Thus, the sheet 1 has much flexibility and permanence, and hard wrinkle due to bending.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermochromic laminated sheet. More specifically, the present invention relates to a thermochromic laminated sheet configured to bring out a clear thermochromic image by bringing a heating or cooling body into contact with the thermochromic laminated sheet and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a reversible thermochromic layer and a film layer are sequentially laminated on a support, a thermochromic image is developed by applying a heating or cooling body, and the image is erased by heating or cooling again. A sheet is disclosed (Japanese Patent Publication No. 3-3603)
No. 1). The above-mentioned conventional sheet tends to wrinkle on the film surface due to bending or the like depending on the bonding structure between the support and the film layer, tends to lose its appearance, and it is difficult to obtain a clear thermochromic image. Further, it lacks flexibility and is not suitable for applications requiring bending or the like.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is hard to cause wrinkles due to bending or the like, it is convenient to store it by folding, and it has good usability and satisfactory durability. Still further, it is an object of the present invention to provide a thermochromic laminated sheet capable of forming a clear thermochromic image with a low writing resistance feeling even in the application of a heating or cooling body in the form of a writing instrument and capable of forming a clear thermochromic image, and a method of manufacturing the same. .

[0004]

SUMMARY OF THE INVENTION The present invention is a thermochromic laminated sheet constructed so that a thermochromic image is produced by bringing a heating or cooling body into contact with the thermochromic laminate sheet. And a thermochromic laminated sheet in which a reversible thermochromic layer and a urethane resin layer are sequentially laminated on a support, and the 100% modulus of the urethane resin layer is 50 to 300 kg / cm ² . Furthermore, the heating or cooling body is a writing implement having a heating or cooling writing tip, and the urethane resin layer has a surface formed on a fine uneven surface, the urethane resin layer, 100%
The modulus is 75 to 200 kg / cm ² , and
It is required that the thickness is 5 to 100 μm and that the thermochromic laminated sheet is manufactured by a dry transfer method.

The support is effective as long as it is a flexible base material having printability, and examples thereof include paper, synthetic paper, knitted fabric, non-woven fabric, synthetic leather, leather, soft plastic, synthetic plastic, and the like. Although a sheet material such as a porous resin body is used, it is particularly preferable to use a synthetic resin porous body or a cloth. As the cloth, a nonwoven fabric or a raised cloth, which is relatively inexpensive, has flexibility and durability, and can withstand practical use such as repeated folding, is suitably used. Further, the synthetic resin porous body, foamed urethane, foamed polyethylene and the like, when applying a heating or cooling body in the form of a writing instrument,
The elasticity of the writing tip and the elasticity of the writing tip corresponding to the writing pressure at the writing tip abutting portion are effective in terms of the heat transfer effect due to the close contact with the writing tip.

In the reversible thermochromic layer, a reversible thermochromic composition containing three components of an organic compound medium that reversibly causes a color reaction between an electron-donating color-forming organic compound and an electron-accepting compound is used. Can be Specifically, Japanese Patent Publication No. 51-3541
No. 4, Japanese Patent Publication No. 51-44706, Japanese Patent Publication No. 5
1-444708, JP-B 52-7776, JP-B-1
JP-A-17154, JP-B-1-29398, JP-A-7-186546 and the like. The color changes before and after a predetermined temperature (discoloration point) as a boundary, and only one specific state can exist in a normal temperature range between the two states before and after the change. That is, the other state is maintained while the heat or cold required for the state to develop is applied, but returns to the state exhibited in the normal temperature range if the application of the heat or cold disappears, so-called, This type changes color by showing a small hysteresis width (ΔH) for temperature-color density due to temperature change.

Also, Japanese Patent Publication No. 4-171 proposed by the present applicant.
No. 54, JP-A-7-179777, JP-A-7-179777
The thermosensitive color-changing color memory composition which exhibits large hysteresis characteristics and discolors described in, for example, JP-A-339997, that is, the shape of a curve plotting a change in coloring density due to a temperature change indicates a temperature in a discoloration temperature range. A type of discoloring material that changes color following a significantly different path when the temperature is increased from a lower temperature side and conversely when the temperature is decreased from a higher temperature side than the discoloration temperature. A reversible thermochromic composition having a characteristic of being able to memorize and retain a state changed at a temperature below the low-temperature side discoloration point or above the high-temperature side discoloration point in a normal temperature range between the points is also effective.

Although the above-mentioned reversible thermochromic composition is effective when used as it is, it is preferable to use it in a microcapsule. That is, under various use conditions, the reversible thermochromic composition is maintained at the same composition and can exert the same function and effect. By being encapsulated in the microcapsules, a chemically and physically stable pigment can be constituted, and the particle size of 0.1 to 100 μm, preferably 2 to 30 μm satisfies the practicality. The microencapsulation is performed by a conventionally known interfacial polymerization method, in S
There are itu polymerization method, in-liquid curing coating method, phase separation method from aqueous solution, phase separation method from organic solvent, melting dispersion cooling method, air suspension coating method, spray drying method, etc., which are appropriately selected according to the application. Is done. Furthermore, on the surface of the microcapsule,
Depending on the purpose, a secondary resin film may be further provided to impart durability, or the surface characteristics may be modified for practical use.

The reversible thermochromic composition or the microcapsule pigment containing the same is dispersed in a medium containing a binder which is a film-forming material and applied as a coloring material such as ink or paint. Can be formed.

The binder is preferably a transparent film-forming resin, and various conventional binders can be used. Examples of the binder include ionomer resins, acrylic resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, and soft binders. Examples thereof include a vinyl chloride resin, a polyester resin, an epoxy resin, and a polyurethane resin, and a polyurethane resin having good adhesiveness to the urethane resin layer is preferably used.

When the reversible thermochromic composition described above is used as a thermochromic ink for forming a reversible thermochromic layer, it is contained in a medium in an amount of 0.5 to 60% by weight, preferably 5 to 60% by weight.
50% by weight can be contained. When the amount is less than 0.5% by weight, it is difficult to see a clear thermochromic effect,
If the amount is more than 10% by weight, the amount is excessive and may be in a decolored state to cause a residual color.

The reversible thermochromic layer is formed by a conventionally known method, for example, printing means such as screen printing, offset printing, gravure printing, coater, tampo printing, transfer, brush coating, spray coating, electrostatic coating, electrodeposition. It can be formed by means such as coating, flow coating, roller coating, and dip coating.

The thickness of the reversible thermochromic layer is 5 to 20.
When the thickness is 0 μm, preferably 10 to 50 μm, the above-described thermochromic effect is sufficiently performed. When the thickness exceeds 200 μm, the degree of freedom in setting the discoloration temperature is lacking in terms of heat conductivity, and the durability of repeated use of the layer having a thickness of 5 μm or less is difficult to satisfy.

Further, the thermochromic composition or the reversible thermochromic composition encapsulated in microcapsules is melt-blended integrally with a thermoplastic resin to form a film or a sheet. A thermochromic layer may be formed.

Further, a plurality of reversible thermochromic layers may be provided, a non-color-changing layer colored with a general colored dye or pigment may be provided below the reversible thermochromic layer, a plurality of reversible thermochromic compositions, a general colored dye, The pigment may be contained in a single layer so that various colors can be seen.

On the reversible thermochromic layer, a 100% modulus is 50 to 300 kg / cm ² , preferably 75 to ² kg / cm ² .
A urethane resin layer having a thickness of 00 kg / cm ² and having fine irregularities on the surface is provided. By providing the urethane resin layer described above, since it has appropriate flexibility and durability, wrinkles hardly occur due to bending, and it can be used repeatedly. In addition, when the surface of the urethane resin layer is formed into a fine uneven surface, writing can be smoothly performed during writing and writing by applying a heating or cooling body in the form of a writing instrument. This is because the surface of the urethane resin layer has fine irregularities, so that the contact area of the heating or cooling body is small, and therefore the static friction resistance is small, so that smooth writing is possible. Even if the urethane resin layer has fine irregularities, if the 100% modulus is less than 50 kg / cm ² , the urethane resin layer is soft, and the irregular surface is maintained by stress deformation at the time of contact with a heating or cooling body. Since it is difficult to write, the frictional resistance increases, and writing cannot be performed smoothly.
On the other hand, when the 100% modulus exceeds 300 kg / cm ² , the urethane resin layer is too hard and easily wrinkles due to bending, making it difficult to use a heating or cooling body, which is not suitable for repeated practical use.

The thickness of the urethane resin layer is 5 to 100 μm.
m is preferable. When the thickness is less than 5 μm, the reversible thermochromic layer is undesirably exposed due to abrasion caused by contact of a heating or cooling body, particularly a writing or heating body having a heating or cooling writing tip. On the other hand, if it exceeds 100 μm, the thermal conductivity is poor, and it is difficult to obtain a desired thermal discoloration effect. Note that the urethane resin layer may be added with resin bead powder to improve the writing feeling.

In the structure of the reversible thermochromic laminate sheet described above, a light stabilizer layer may be appropriately provided. Specifically, the light stabilizer layer is selected from an ultraviolet absorber, an antioxidant, an antioxidant, a singlet oxygen quencher, a superoxide anion quencher, an ozone decolorant, a visible light absorber, and an infrared absorber. This is a layer in which the light stabilizer is fixed in a dispersed state. The function can be improved by adding an antioxidant, an antistatic agent, a polarity imparting agent, a thixotropic agent, an antifoaming agent, and the like to the reversible thermochromic layer and the urethane resin layer as necessary.

It is effective to produce the thermochromic laminated sheet by applying a dry transfer method in terms of productivity, quality stability, production cost and the like. When the manufacturing method is specifically described, a urethane resin solution is applied by a method such as doctor coat, reverse roll coat, spray coat, wire coat, etc. on a matte surface having fine irregularities or a release paper having a matte surface. Thereafter, dried to form a urethane resin layer, a reversible thermochromic ink is applied on the urethane resin layer in the same manner and dried to form a reversible thermochromic layer, and then the reversible thermochromic layer is formed. After applying an adhesive in the same manner as above, the support is attached. The thermochromic laminated sheet obtained as described above is 60 to
After leaving at 80 ° C. for 1 to 4 days to completely adhere the support and the reversible thermochromic layer, it is preferable to remove the release paper.

As a method of bonding the support, the reversible thermochromic layer, and the support, a support coated with an adhesive in advance may be bonded to the reversible thermochromic layer. Also, the adhesive is
A configuration in which hot fusion is performed using a hot melt resin may be employed.

The heating or cooling discolored body applied to the thermochromic laminated sheet may be a writing form having a tapered tip or a stamp having a character, design, pattern or the like formed at the tip. And an electric heating discoloration tool equipped with a resistance heating element (Japanese Utility Model Application Laid-Open No. 62-139573).
JP-A-4-50100), a heating pen filled with hot water or the like (disclosed in JP-A-2-106299, etc.), and a cooling discoloration tool have been previously proposed by the present applicant. Cooling discoloration device using Peltier element
No. 18915), a cooling pen filled with a coolant such as cold water or ice chips. In addition, the heating or cooling discoloration body may be a rotating body having ice chips, hot water, or other heating or cooling medium built therein, and the rotating body may be applied to a holding body.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1 (see FIG. 1) Release paper for urethane resin (manufactured by Lintec, trade name: EV
-130TPD, mat type), urethane resin solution (manufactured by Dainichi Seika, solid content 20%, 100% modulus 12)
0 kg / cm ² ) with a doctor coat to 100 g / m ²
After drying, a urethane resin layer 5 having a thickness of 20 μm was formed.

On the urethane resin layer, 50 parts of a reversible thermochromic material containing a thermochromic color memory composition (blue →→ colorless, coloring temperature: 15 ° C., erasing temperature 30 ° C.), 50 parts of a urethane emulsion Was applied on a rotary screen at 100 g / m ² and dried to form a reversible thermochromic layer 4.

Next, on the reversible thermochromic layer 3, a urethane resin solution (manufactured by Dainippon Ink, 30% solids, containing 4.5 parts of isocyanate) was wire-coated at 50 g / m 2.
After coating so as to be ² , the adhesive layer 3 was formed by drying.

A brushed polyester cloth (40d, double tricot) was adhered as a support 2 on the adhesive layer. After leaving at 60 ° C. for 2 days, the release paper was peeled off to remove the thermochromic laminated sheet 1. I got

The thermochromic laminated sheet 1 is hardly wrinkled even when bent, and the entire surface is heated to 30 ° C. or higher to give a white thermochromic laminated sheet with ice as a heating or cooling body 6. When writing was performed with the filled writing tip having a temperature of 15 ° C. or less, writing was performed smoothly at the start of writing and during writing, and the color-memory thermochromic composition developed and blue handwriting was obtained. The handwriting was stored at a temperature lower than 30 ° C. When the thermochromic laminated sheet on which the handwriting is drawn is heated again to 30 ° C. or higher, it returns to a white state and can be used repeatedly.

Example 2 (see FIG. 2) Release paper for urethane resin (trade name, manufactured by Dai Nippon Printing Co., Ltd.)
DN-TP-APT (DE107), satin pattern], urethane emulsion [Dai Nippon Ink Co., Ltd., solid content 3]
5%, 100% modulus 60 kg / cm ² ] was applied by spray coating to 200 g / m ² , and dried to form a urethane resin layer 5 having a thickness of 70 μm.

On the urethane resin layer, a reversible thermochromic composition (blue at less than 20 ° C. and colorless at 20 ° C. or more)
5 parts of a reversible thermochromic material containing, 2 parts of a fluorescent pink pigment,
A reversible thermochromic ink composed of 93 parts of an acrylic emulsion (hot melt resin) was applied with a knife coater to 140
g / m ² , and then dried to form a reversible thermochromic layer 4.

Next, the reversible thermochromic layer side was bonded to a nonwoven fabric (polyester and nylon, 75 g / m ² ) using a heat roll as the support 2, and the release paper was removed to obtain a thermochromic laminated sheet 1.

The thermochromic laminate sheet is hardly wrinkled even when bent, and exhibits a pink color at room temperature of 25 ° C., but the heating or cooling body 6 has a writing tip temperature of 15% when filled with ice. When writing was performed with a cooling pen at a temperature of not more than ° C, writing could be performed smoothly at the start of writing and during writing, and the reversible thermochromic composition developed color to obtain purple handwriting. In addition, when the handwriting was left to reach a temperature of 25 ° C. or higher again, it became pink and could not be visually recognized. The thermochromic laminate sheet is again 2
When cooled to below 0 ° C., it turns purple and can be used repeatedly. In addition, the thermochromic laminated sheet has a temperature of 18 ° C.
Although it has a purple color at room temperature, when a hot stamp filled with warm water and the tip of which is at least 20 ° C. is brought into contact,
The reversible thermochromic composition was decolorized to obtain a pink thermochromic image. When the image was left at a temperature of 20 ° C. or lower again, the image became purple and became invisible. When the thermochromic laminate sheet is heated to 20 ° C. or higher again, it becomes pink and can be used repeatedly.

Example 3 (see FIG. 1) Release paper for urethane resin [manufactured by Lintec, trade name: EV
-130 TPD, mat type) and a gravure coat of a urethane resin solution (manufactured by Sanyo Chemical Industries, Ltd., solid content 30%, 100% modulus 290 Kg / cm ² ) by gravure coating.
g / m ² and then dried to a thickness of 6 μm
The urethane resin layer 5 was formed.

On the urethane resin layer, a reversible thermochromic composition (black at less than 30 ° C. and colorless at 30 ° C. or more)
Is coated on a rotary screen at 100 g / m ² with a reversible thermochromic ink comprising 20 parts of an oil-based reversible thermochromic material containing 80 parts and 80 parts of a urethane resin (solid content: 40%), and then dried. A reversible thermochromic layer 4 was formed.

Next, an acrylic adhesive (manufactured by Dainippon Ink, 40% solids) is applied on the reversible thermochromic layer 4 to form an adhesive layer 3. (200%) and left at 60 ° C. for 2 days, and then the release paper was removed to remove the thermochromic laminated sheet 1
I got

The thermochromic laminate sheet is hardly wrinkled even when bent, and has a black color at room temperature of 25 ° C., but the heating or cooling body 6 is filled with warm water at a writing tip temperature of 40 ° C. As a result, the reversible thermochromic composition was discolored, and white handwriting was obtained. When the handwriting was left at a temperature of 30 ° C. or lower again, the handwriting changed color to black and became invisible. When the thermochromic laminate sheet is again cooled to 30 ° C. or higher, it becomes white and can be used repeatedly.

Comparative Example 1 A thermochromic laminate was prepared in the same manner as in Example 1 except that the urethane resin solution used for the urethane resin layer was made by Dainippon Ink and had a solid content of 20% and a 100% modulus of 45 kg / cm ^2. I got a sheet. The thermochromic laminated sheet,
Although it is more flexible than the cursive body of Example 1,
Due to repeated use, the urethane resin layer is severely worn.
In addition, when writing with a cooling pen, resistance is high at the time of initial writing and writing, and a heavy writing feeling is obtained.

Comparative Example 2 A thermochromic laminated sheet was obtained in the same manner as in Example 1, except that the release paper was changed to a gloss type (manufactured by Lintec Corporation, trade name: CPUG). When the thermochromic laminated sheet is written with the cooling pen of Example 1, the writing pen has a feeling that the cooling pen is caught on the object to be written in initial writing.
Also, it is difficult to write smoothly when writing.

Comparative Example 3 A thermochromic laminate was prepared in the same manner as in Example ² except that the urethane resin solution used for the urethane resin layer was made by Dainippon Ink and had a solid content of 20% and a 100% modulus of 350 kg / cm ^2. I got a sheet. The thermochromic laminated sheet is harder than the writing body of Example 1, and wrinkles are generated by bending. In addition, when writing with a cooling pen, the resistance is small at the time of initial writing and writing and has a light writing feeling, but the handwriting is not clear.

[0038]

The thermochromic laminated sheet of the present invention is excellent in flexibility and durability, can be folded and stored when not in use, and is hardly wrinkled by bending or the like, so that it can be heated or cooled. It is possible to provide a thermochromic laminated sheet having a relatively large area, which retains planarity when the body is applied and can form a clear thermochromic image. Further, in a system to which a heating or cooling body in the form of a writing instrument is applied, frictional resistance during writing is appropriate, and writing can be performed smoothly. Furthermore, by manufacturing by a dry transfer method, it is possible to provide a thermochromic laminated sheet that satisfies productivity, quality stability, etc., and is relatively inexpensive, and is a thermochromic laminated sheet that is effective in the field of toys and writing materials. And a method for producing the same.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view of a main part of an embodiment in which a heating or cooling body is applied to the thermochromic laminated sheet of the present invention.

FIG. 2 is an explanatory longitudinal sectional view of a main part of another embodiment in which a heating or cooling body is applied to the thermochromic laminated sheet of the present invention.

FIG. 3 is an explanatory longitudinal sectional view of a main part of another embodiment in which a heating or cooling body is applied to the thermochromic laminated sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermochromic laminated sheet 2 Support 3 Adhesive layer 4 Reversible thermochromic layer 5 Urethane resin layer 6 Heating or cooling body

Claims (4)

[Claims] 1. A thermochromic laminated sheet configured to bring out a thermochromic image by bringing a heating or cooling body into contact, wherein the thermochromic laminated sheet is reversibly thermochromic on a support. Layer and a urethane resin layer are sequentially laminated, and the urethane resin layer has a 100% modulus of 50 to 300.
A thermochromic laminated sheet having a weight of kg / cm ² . 2. The thermochromic device according to claim 1, wherein the heating or cooling body is in the form of a writing implement having a heating or cooling writing tip, and the urethane resin layer is formed with a fine uneven surface. Laminated sheet. 3. The thermochromic laminated sheet according to claim 1, wherein the urethane resin layer has a 100% modulus of 75 to 200 kg / cm ² and a thickness of 5 to 100 μm. 4. The method according to claim 1, wherein the substrate is manufactured by a dry transfer method.
5. The method for producing a thermochromic laminated sheet according to any one of the above-mentioned items.