JP2000001053A - Thermosensitive coloring material, thermosensitive coloring element and manufacturing method thereof, and laminate for forming thermosensitive coloring element and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] To provide a thermosensitive coloring element that irreversibly develops a color even in a low temperature region by utilizing surface plasmon absorption of metal fine particles. SOLUTION: Metal particles dispersed in a solid matrix 1 having a melting point in a low temperature region are converted into metal fine particles 2 by photoreduction (a). Aggregation of the metal fine particles dispersed in the matrix is suppressed when the solid matrix is solid (b). However, when the ambient temperature rises and the matrix is liquefied, the matrix is agglomerated to form the metal fine particles 12 having an increased particle size, and develop color due to surface plasmon absorption (c). Since the metal fine particles are irreversibly aggregated, even if the temperature is lowered after coloring, the color is not erased and the heat history can be visually recognized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive coloring material, a thermosensitive coloring element, and a method for manufacturing the same. The present invention also relates to a thermosensitive coloring element-forming laminate used for producing a thermosensitive coloring element, and to a method for producing the laminate. The heat-sensitive coloring material and element of the present invention are particularly useful for temperature control of cold storage systems, frozen foods, refrigerated foods and the like.

[0002]

2. Description of the Related Art Conventionally, as a heat-sensitive coloring material or a heat-sensitive display material, a leuco dye, a color developer and a zirconium compound are contained on a support as disclosed in, for example, JP-A-61-110585. A material in which a thermosensitive coloring layer and a protective layer are sequentially provided is known. Further, as another example, a thermal display element as disclosed in Japanese Patent Application Laid-Open No. 7-149057 is known. As shown in FIG. 13, the thermal display element has a structure in which an organic material layer 23 is laminated on a colored layer 21 via an air layer 22. The organic layer 23 is made of a material whose light scattering reversibly changes depending on the temperature. This layer is specifically composed of a resin base material and an organic low-molecular substance dispersed in the base material, and a material that reversibly changes between a cloudy state and a transparent state by heating, It is composed of a polymer liquid crystal having a thermotropic liquid crystal property. Therefore, when the organic material layer 23 is transparent, the color of the colored layer 21 can be confirmed from the organic material layer 23 side, but when the organic material layer 23 is cloudy, the color of the colored layer 21 can be confirmed from the organic material layer 23 side. Can not do it. Thus, the temperature change can be visually recognized.

[0003]

However, the above-mentioned conventional thermosensitive coloring material is irreversible because it changes reversibly between coloring and decoloring, or between cloudy state and transparent state, depending on temperature change. Cannot change the color of the material. Therefore, once the temperature rises, if the temperature subsequently falls, the process of temperature rise cannot be confirmed as a heat history. In addition, conventional thermosensitive coloring materials often have a color changing temperature of about 70 ° C. to 80 ° C., and are not suitable for temperature control of refrigerated and frozen foods. For such temperature control, for example, a thermosensitive coloring material which is colorless and transparent at a relatively low temperature (（6 ° C.) but irreversibly develops at a temperature of about room temperature (20 ° C.) or more is required.

[0004] In view of such circumstances, an object of the present invention is to provide a thermosensitive coloring material, a thermosensitive coloring element whose color tone changes irreversibly even at a relatively low temperature, and a laminate for forming the element. Another object of the present invention is to provide a method for manufacturing the thermosensitive coloring element and a method for manufacturing the laminate.

[0005]

In order to achieve the above object, the present invention utilizes a solid matrix in which fine metal particles are dispersed. Diffusion and aggregation of the dispersed metal fine particles are promoted by the supply of heat energy from the outside, and the metal fine particles exhibit surface plasmon absorption due to an increase in the particle diameter of the metal fine particles accompanying the aggregation. Since the aggregation of the metal fine particles is essentially an irreversible phenomenon, color development due to surface plasmon absorption of the metal fine particles is also irreversibly observed. The heat-sensitive coloring material of the present invention, the metal fine particles dispersed in the solid matrix in the heat-sensitive coloring element, regardless of whether they can be actually recognized as particles, have the property of irreversibly forming a color if the particle diameter increases due to aggregation. As long as it is provided, fine particles having an extremely small particle diameter existing as atoms or a size close to the atoms are included.

That is, the first thermosensitive coloring material of the present invention comprises a solid matrix having tackiness and fine metal particles dispersed in the solid matrix, and the fine metal particles promoted by external heat supply. Is characterized by exhibiting an irreversible color tone change by the enlargement of the particle size.

[0007] According to such a thermosensitive coloring material, the heat history can be confirmed by an irreversible change in color tone.
Further, since the color tone change utilizing the surface plasmon absorption of metal fine particles occurs even at a low temperature of about 0 ° C.,
It is also suitable for temperature control of frozen foods and the like. In addition, since a solid matrix having an adhesive property is used, it can be directly attached to an object to be measured or attached to a substrate.

Solid matrices having such adhesive properties include natural rubber adhesives, styrene / butadiene latex adhesives, thermoplastic rubber block copolymer adhesives, butyl rubber adhesives, polyisobutylene adhesives, acrylic adhesives, It is preferable to include at least one material selected from a vinyl ether polymer adhesive and a silicone adhesive.

The second heat-sensitive coloring material of the present invention comprises a solid matrix and fine metal particles dispersed in the solid matrix. Is characterized by exhibiting an irreversible color tone change due to an increase in the particle size.

[0010] Even with such a thermosensitive coloring material, it is possible to confirm the heat history in a low temperature region by a color tone change utilizing surface plasmon absorption of metal fine particles. The aggregation of the metal fine particles in the thermosensitive coloring material is greatly promoted when the solid matrix is liquefied. Therefore, according to the thermosensitive coloring material, the heat history can be estimated from the melting point of the solid matrix. The temperature at which the solid matrix liquefies is specifically -20 ° C.
To 20 ° C. Since the temperature at which the solid matrix is liquefied can be roughly estimated from the melting point of the solid matrix, a material having a melting point in the above temperature range may be used as the solid matrix. However, in order to obtain a more precise measurement result, it is preferable to consider the freezing point depression.

The heat-sensitive coloring materials include gold, platinum, silver, copper,
It preferably contains at least one metal fine particle selected from tin, rhodium, palladium and iridium.
Since such a metal is hardly affected by oxygen and impurities, it can be deposited as relatively pure fine particles.

The thermosensitive coloring material preferably contains metal fine particles generated by photoreduction of metal ions. When the metal ions are reduced from the matrix in which the metal ions are dispersed to the metal fine particles, the metal fine particles dispersed in the matrix can be obtained so as not to be unevenly distributed.

It is preferable that the thermosensitive coloring material contains metal fine particles having a particle size small enough not to exhibit color due to surface plasmon absorption. Coloring occurs.

The heat-sensitive coloring element of the present invention comprises a solid matrix in which fine metal particles are dispersed, and a color-forming layer which exhibits an irreversible color tone change due to the aggregation of the fine metal particles promoted by the supply of heat from the outside; And a substrate supporting the layer.

With such a thermosensitive coloring device, the irreversible coloring based on the surface plasmon absorption of the fine metal particles makes it possible to visually confirm the thermal history of the device even in a low temperature region.

In the above thermosensitive coloring device, the coloring layer preferably contains the second thermosensitive coloring material. Further, it is preferable that a protective layer is disposed on the coloring layer.

In the above thermosensitive coloring device, it is preferable that at least one selected from an adhesive layer and an adhesive layer is provided on the substrate. According to this preferred example, the coloring layer is securely fixed to the substrate by the adhesive layer or the adhesive layer. The pressure-sensitive adhesive layer preferably contains at least one of the pressure-sensitive adhesives listed above.

Further, in the thermosensitive coloring element, it is preferable that the coloring layer contains the first thermosensitive coloring material. According to this preferred example, since the solid matrix itself has adhesiveness, it is possible to directly fix the coloring layer to the substrate without providing an adhesive layer.

Further, the thermosensitive coloring device preferably includes two or more coloring layers. According to this preferred example, it is easy to clearly recognize the change in color tone, and it is also possible to observe color development in a short time.

The first laminate for forming a thermosensitive color-forming element of the present invention comprises a solid matrix in which fine metal particles are dispersed, and undergoes an irreversible color change due to the aggregation of the fine metal particles promoted by the supply of heat from the outside. A color developing layer is provided, and a support for supporting the color forming layer is provided, and an adhesive surface for fixing the color forming layer to a base which is a part of the thermosensitive color developing element is provided.

When such a laminate is used, a thermosensitive coloring element can be manufactured by attaching a coloring layer to an optional substrate when necessary using the adhesive surface prepared on the laminate.

The second laminate for forming a thermosensitive coloring element of the present invention comprises a matrix forming material, metal ions and α.
-Containing a hydrogen-containing alcohol, when the metal ions are reduced by light irradiation and the metal fine particles are dispersed in a solid matrix, irreversible color change due to aggregation of the metal fine particles promoted by the supply of heat from the outside; Comprising a metal-containing ion layer exhibiting the following, and a support for supporting the metal-containing ion layer, and having an adhesive surface for fixing the metal-containing ion layer to a substrate that is a part of the thermosensitive coloring device. Features.

When such a laminate is used, the metal-containing ionic layer can be adhered to an optional substrate when necessary, using the adhesive surface prepared on the laminate. This metal-containing ion layer can be converted into a color-forming layer by reducing metal ions by light irradiation to form metal fine particles. The photoreduction of the metal-containing ion layer may be carried out on a support or after being attached to a substrate. In the photoreduction step, the α-hydrogen-containing alcohol acts as a reducing agent. In addition, ethylene glycol, propylene glycol, polypropylene glycol, and the like can be used as the α-hydrogen-containing alcohol.

In the laminate for forming a thermosensitive coloring device, the solid matrix preferably has a melting point of -20 ° C to 20 ° C.

The laminate for forming a thermosensitive coloring element preferably contains an adhesive layer having an adhesive surface for fixing to the substrate. This adhesive layer preferably contains at least one of the adhesives listed above.

In the thermosensitive coloring element-forming laminate, the solid matrix has adhesiveness, and the adhesive surface for fixing the coloring layer or the metal-containing ion layer to a substrate which is a part of the thermosensitive coloring element. Preferably, it is provided. According to this preferred example, the base can be surely integrated without forming the adhesive layer.

It is preferable that the laminate for forming a thermosensitive coloring device includes two or more coloring layers or metal-containing ion layers.
This is because, similarly to the above, it is easy to visually recognize the color tone change, and it is possible to observe the color development in a short time.

The laminate for forming a thermosensitive coloring device preferably has a release layer on the adhesive surface. This is for suppressing the deterioration of the adhesive property on the adhesive surface. Examples of such a laminate include a laminate in which a metal-containing ion layer or a coloring layer, an adhesive layer, and a release layer are laminated in this order on a support. Two or more metal-containing ion layers or color-forming layers may be laminated. Further, the release layer preferably contains a release agent layer and a release agent support layer.

The laminate for forming a thermosensitive coloring device preferably has a release agent layer formed on a support. This is because the support can be easily peeled after the color-forming layer or the like is transferred to the substrate. Also, when a release agent layer is formed on the surface opposite to the surface supporting the color forming layer and the like, and this surface is in contact with the adhesive surface, when laminated or wound, the deterioration of the adhesive characteristics of the adhesive surface is suppressed as described above. can do.

Such a laminate for forming a thermosensitive coloring device is as follows:
For example, the support may include an adhesive surface above the first surface supporting the metal-containing ion layer or the color-forming layer, and a release agent layer on the second surface opposite to the first surface, respectively. It is wound so that the adhesive surface and the release agent layer are in contact with each other.
It is convenient to preserve when it is wound in a spiral like this. In addition, if a long laminate is wound and prepared, a laminate of a required size can be appropriately cut and attached to a base, so that a thermosensitive coloring element can be easily and efficiently manufactured. can do.

In the thermosensitive coloring element-forming laminate, it is preferable that a protective layer made of at least one selected from inorganic substances and resins is provided on the support. This is because the influence of impurities in the support on the metal-containing ion layer or the coloring layer can be suppressed.

The method for producing a laminate for forming a thermosensitive coloring device of the present invention comprises a matrix-forming material, metal ions and α-
The method is characterized by including a step of preparing a raw material mixture containing a hydrogen-containing alcohol, and a step of forming a metal-containing ion layer containing the raw material mixture on a support.

It is preferable that the method for producing a laminate for forming a thermosensitive coloring element further includes a step of forming an adhesive layer on the metal-containing ion layer.

The method for producing a laminate for forming a thermosensitive coloring device preferably further comprises a step of forming the metal-containing ion layer and then cooling the metal-containing ion layer to a melting point of the matrix-forming material or lower. The matrix forming material preferably has a melting point at -20C to 20C.

In the method for producing a laminate for forming a thermosensitive coloring element, the method further comprises the step of photoreducing metal ions by irradiating the metal-containing ion layer with light to form a coloring layer in which fine metal particles are dispersed in a solid matrix. It is preferred to include.

In the method for producing a laminate for forming a thermosensitive coloring device, it is preferable to use a matrix-forming material that imparts tackiness to the metal-containing ion layer. in this case,
Since the matrix itself has tackiness, there is no need to further form an adhesive layer.

The method for producing a laminate for forming a thermosensitive coloring device preferably further comprises a step of forming a release agent layer on the support before forming the metal-containing ion layer.

The method for producing a thermosensitive coloring element of the present invention comprises the above-described thermosensitive coloring element-forming laminate or the thermosensitive coloring element-forming laminate obtained by the above-described method, comprising the steps of:
It is characterized in that it is fixed on the substrate by an adhesive surface contained in any one layer selected from a metal-containing ion layer and an adhesive layer.

The thermosensitive coloring device of the present invention can also be directly manufactured without passing through the above-mentioned laminate. The method for producing such a thermosensitive coloring device includes a step of preparing a raw material mixture containing a matrix-forming material, a metal ion and an α-hydrogen-containing alcohol, and a step of forming a metal-containing ionic layer containing the raw material mixture on a substrate. Reducing the metal ions by irradiating the metal-containing ion layer with light.

According to such a method, it is possible to manufacture a thermosensitive coloring element whose thermal history can be confirmed even in a low temperature region.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) One embodiment of the thermosensitive coloring material of the present invention will be described below. This thermosensitive coloring material is a material using an adhesive solid matrix as described above as the first thermosensitive coloring material.

As the solid matrix having tackiness, the above-mentioned materials having tackiness can be used. However, in order to easily confirm color development due to surface plasmon absorption of fine metal particles, the color tone must be adjusted. It is preferable to select a thin material, and it is preferable to select a material that does not have strict bonding conditions such as a heating condition and time during bonding. From such a viewpoint, an acrylic emulsion pressure-sensitive adhesive is particularly suitable.

In this solid matrix, fine metal fine particles are dispersed. The diffusion movement of the metal fine particles is activated by heat energy applied from the outside. Therefore, as the ambient temperature around the material increases,
Agglomeration of the fine metal particles in the solid matrix is promoted.
And when the aggregated metal fine particles reach a certain particle size,
Due to the surface plasmon absorption of the metal fine particles, coloring is observed.

The particle size of the fine metal particles exhibiting surface plasmon absorption varies depending on the type of metal, but is usually several nm. The heat-sensitive coloring material contains metal fine particles having a particle size smaller than the particle size at which coloring by surface plasmon absorption is visually recognized.

The average particle size of the fine metal particles after aggregation differs depending on the type of metal, but is usually preferably in the range of 1 nm to 100 nm, and is preferably 3 nm to 80 nm for uniform coloring.
More preferably, it is within the range.

The amount of the fine metal particles dispersed in the solid matrix is not particularly limited, but is preferably in a range where the particle size can be easily controlled. Specifically, the content of the metal fine particles is preferably 0.01 to 20% by weight.
More preferably, it is 1 to 10% by weight. If it is added excessively, the layer partially changes to a dark color, making it difficult to confirm the thermal history.

Such a thermosensitive coloring material can be obtained by photoreducing metal ions dispersed in a matrix. This step will be described in embodiments and examples described later.

(Second Embodiment) Hereinafter, another embodiment of the thermosensitive coloring material of the present invention will be described. This thermosensitive coloring material is a material using a solid matrix having a temperature at which it liquefies in the range of −20 to 20 ° C., as described above as a preferred embodiment of the second thermosensitive coloring material.

As such a solid matrix material, it is preferable to select a material having a melting point in the above temperature range from an inorganic substance, an organic substance and a composite thereof. The material preferably has a melting point suitable for the state of use and is light in color.

The following is an example of a solid matrix. As the inorganic substance, for example, water (melting point: 0 ° C., hereinafter the melting point is indicated in parentheses) and silicon tetrabromide (5.2 ° C.) can be used. As the organic substance, for example, cyclohexane (6.5 ° C.), cyclohexylbenzene (7.4)
C) and p-chlorotoluene (7.5
C), halogenated hydrocarbons such as 1,2-dibromoethane (10C), alcohols such as n-decanol (7C), ethers such as 1,8-cineole (1.3C),
Ketones such as methyl-n-heptyl ketone (-7.5 ° C), esters such as ethyl cinnamate (7 ° C), polyhydric alcohol derivatives such as ethylene glycol (-13 ° C),
Acids such as citraconic anhydride (7 ° C) and butyric acid (-5.3 ° C), phenols such as dodecylphenol (-7 ° C) and nonylphenol (-8 ° C), monoisopananolamine (2 ° C), tetramethyl Examples include nitrogen-containing compounds such as urea (-1 ° C), sulfur-containing compounds such as sulfolane (9 ° C), and fluorine compounds such as hexafluorobenzene (5.1 ° C). The solid matrix may be composed of a substance containing a plurality of materials as exemplified above.

As described above, in this thermosensitive coloring material, when the solid matrix is liquefied from a solidified state, the diffusion movement of the metal fine particles is rapidly activated. That is, in the thermosensitive coloring material, when the solid matrix is kept in an atmosphere at a temperature higher than the temperature at which the solid matrix is liquefied, irreversible aggregation of the metal fine particles is promoted, and the coloring is irreversible.

The change in the state of the thermosensitive coloring material will be described with reference to FIG. FIG. 1A shows a state in which metal fine particles 2 are dispersed in a matrix 1 having a liquefaction temperature Tm at a temperature lower than Tm. Since the particle diameter of the metal fine particles is smaller than the particle diameter at which the metal exhibits surface plasmon absorption, no color development is observed in this state.

FIG. 1B shows a state in which the thermosensitive coloring material is maintained at a temperature lower than the liquefaction temperature Tm. Since the temperature is low and the matrix 1 remains solid, the movement of the fine particles is suppressed, and no coloring is observed.

However, as shown in FIG. 1 (c), when the thermosensitive coloring material is maintained in an environment having a temperature equal to or higher than the liquefaction temperature Tm, the matrix 1 liquefies, and metal fine particles are easily aggregated and liquefied. The particle size of the metal fine particles in the matrix 11 increases, and becomes the metal fine particles 12 having a particle size showing surface plasmon absorption.

In such a thermosensitive coloring material, if a substance having a melting point near the temperature at which the quality of the insulated material deteriorates is selected as the matrix forming material, the coloring starts in a short time even at a low temperature. It is possible to provide a material suitable for confirming the heat history of foods and the like that deteriorate in a short time.

Such a thermosensitive coloring material can also be obtained by photoreducing metal ions dispersed in a matrix. The step of dispersing the metal ions is performed in a liquid containing the matrix forming material (for example, a molten matrix forming material), and the photoreduction of the metal ions is preferably performed in a solid matrix. This step will be described in embodiments and examples described later.

As shown in the cross section in FIG. 2, the thermosensitive coloring material described in the first and second embodiments is formed by molding a material in which metal fine particles 2 are dispersed in a solid matrix 1 into a predetermined shape. be able to. However, as described in the following embodiments, it can be integrated with a base or the like and further used as an element convenient for actual use.

(Third Embodiment) Hereinafter, one embodiment of the thermosensitive coloring device of the present invention will be described. As shown in FIG. 3A, the thermosensitive coloring device includes a coloring layer 3 made of a thermosensitive coloring material and a base 6 supporting the coloring layer 3.

In the color forming layer 3, fine metal particles 2 are dispersed in a solid matrix 1. As described in the above embodiment, when the fine metal particles 12 having an increased particle diameter due to agglomeration are generated (FIG. 3B), the thermosensitive coloring element irreversibly develops color due to surface plasmon absorption.

The color-forming layer 3 is not limited to the heat-sensitive color-forming material as described in the above embodiment, and irreversible color tone changes due to surface plasmon absorption of the metal fine particles occur as the particle size of the metal fine particles increases. Materials can be used.

Materials which can form a solid matrix in which such metal fine particles are dispersed and which are not exemplified in the above embodiment are exemplified from inorganic substances and organic substances. As the inorganic substance, silicon oxide, aluminum oxide, titanium oxide, or the like can be used. As the organic substance, polyacrylic acid, polyacrylate, polyethylene oxide, or the like can be used. Among the organic substances, as the resin, polyvinyl alcohol, polyvinyl butyral, polystyrene, acrylonitrile / styrene copolymer, fluororesin, or the like can be used. These matrix-forming materials are:
It has preferable characteristics as a medium for dispersing metal fine particles reduced from metal ions. The matrix forming material is
It is preferable to contain at least one of the materials exemplified above, and they may be appropriately mixed (for example, as an inorganic / organic composite).

An example of a method for manufacturing a thermosensitive coloring device using a solid matrix made of such a material will be described below. First, a matrix forming material is added to a solvent selected according to the type together with a metal compound to form a solution containing metal ions. An α-hydrogen-containing alcohol is also added to the solution to reduce metal ions. Next, this solution is disposed on a predetermined substrate by printing, coating, or the like. The solution may be partially or entirely impregnated into the substrate. Further, polymerization, gelation, and the like of the matrix forming material may be performed in a solution. Further, through a step of removing the solvent by drying or the like, the metal ions are fixed in a state of being dispersed in the matrix. Then, the metal ions are reduced to fine metal particles to form a color-forming layer. The reduction of metal ions can be specifically performed by irradiation with ultraviolet rays. The irradiation amount of the ultraviolet ray may be appropriately selected depending on the desired coloring characteristics.

The method of manufacturing the thermosensitive coloring device is not limited to the above method, but may be changed as appropriate according to the matrix forming material used for the coloring layer. For example, when the matrix forming material is liquid at normal temperature (for example, -20 ° C to 20 ° C).
In the case where the matrix-forming material has a melting point, a metal ion is added to the matrix-forming material itself together with the α-hydrogen-containing alcohol, placed on a substrate, cooled and solidified, and then subjected to photoreduction of metal ions. What is necessary is just to implement.

As will be described later, instead of forming the color-forming layer on the substrate, a layer may be formed on a support in advance, and this layer may be transferred to the substrate.

The amount of the thermosensitive coloring material arranged on the substrate is not particularly limited, but is preferably 0.1 mg to 100 mg, more preferably 1 mg / cm ² of the substrate.
1 mg to 10 mg per cm ² .

On the other hand, the substrate 6 supporting the color-forming layer 3 is not particularly limited.
Cloth, paper, glass can be used.

(Fourth Embodiment) Another embodiment of the thermosensitive coloring device of the present invention will be described below. As shown in FIG. 4, the thermosensitive coloring device includes a coloring layer 3 made of a thermosensitive coloring material, a base 6 supporting the coloring layer, and an adhesive layer 4 for bonding the base and the coloring layer. I have.

For the pressure-sensitive adhesive layer 4, the pressure-sensitive adhesives exemplified above can be used. The arrangement amount of the adhesive layer is appropriately selected depending on the material, but is preferably 10 g / m ² or less, and particularly preferably 0.5 to 3 g / m ² from the viewpoint of improving peel strength.

By arranging the adhesive layer 4 between the coloring layer 3 and the substrate 6, the coloring layer and the substrate can be integrated without limiting the shape, material and the like of the substrate. The pressure-sensitive adhesive layer 4 is not limited to this, and may be replaced with an adhesive layer for fixing the base and the color-forming layer.

(Fifth Embodiment) Hereinafter, another embodiment of the thermosensitive coloring device of the present invention will be described. As shown in FIG. 5, the thermosensitive coloring device includes a coloring layer 3, which is made of a thermosensitive coloring material, an adhesive layer 4, and a substrate 6 which supports the coloring layer via the adhesive layer.
In addition to the above, a protective layer 5 is included on the coloring layer.

The protective layer 5 is particularly preferably formed when the color-forming layer 3 contains a matrix that liquefies in the operating temperature range, such as the second heat-sensitive color-forming material. This is because the liquefied matrix material can be confined. In addition, if a material having a property of shielding ultraviolet light is used, the color reproducibility of the element can be improved. Although not particularly limited, the protective layer is preferably made of a material that allows the coloring of the coloring layer to be visually recognized, for example, glass, plastic, or the like.

(Sixth Embodiment) Another embodiment of the thermosensitive coloring device of the present invention will be described below. As shown in FIG. 6, the thermosensitive coloring device has two coloring layers 3 on a substrate 6.
a, 3b.

When the coloring layers are laminated as in this element,
The change in color tone can be clarified as compared with a thermosensitive coloring element having a single coloring layer. In particular, it is possible to obtain a color that can be clearly confirmed with the naked eye in a short time. In particular, when it is necessary to confirm a short-time heat history in a low-temperature atmosphere having a low coloring speed, such a thermosensitive coloring device is effective. The degree of color development becomes deeper and clearer as the number of material layers increases, as compared to a device having a single thermosensitive coloring material layer.

In particular, in an element having a plurality of color-forming layers, as shown in FIG. 7, by forming a protective layer 16 made of a resin or an inorganic substance on the surface of the substrate, the color-forming layers 3a and 3b It is preferable to suppress the reaction between the metal fine particles and impurities present on the surface of the base 6. As the protective layer 16, an inorganic substance such as silica gel or a resin such as polyvinyl alcohol or polyacrylic acid is preferable.

When a further layer is formed on the coloring layer, a drying step of the coloring layer is required, and the drying step increases as the number of layers increases. In particular, the first color forming layer 3a that is in direct contact with the base is exposed to a high-temperature atmosphere for drying for a long time, and is easily affected by impurity diffusion from the base. However, by forming the protective layer 16 as described above, it is possible to increase the temperature of the drying treatment at the time of manufacturing, so that the time required for manufacturing can be reduced.

The adjustment ratio of the mixture in the color-forming layer is as follows:
It is not necessary to make each layer constant, and a coloring layer having different coloring characteristics may be used.

(Seventh Embodiment) Hereinafter, one embodiment of a method for manufacturing a thermosensitive coloring device, which is performed via a laminate for forming a thermosensitive coloring device, will be described. This thermosensitive coloring element includes the thermosensitive coloring material described in the first embodiment, and this material has an adhesive surface for fixing to the base.

First, a raw material mixture containing an adhesive matrix-forming material, metal ions, and an α-hydrogen-containing alcohol is prepared. As the matrix-forming material, any of the above-mentioned adhesive materials, as the metal ion, the above-mentioned metal compound, and as the α-hydrogen-containing alcohol, the above-mentioned alcohol can be used. The addition amount of the metal ion depends on the operating temperature range,
In consideration of the type of metal and the like, it is preferable to adjust the average particle diameter after aggregation to be in the above-mentioned preferable range.

Next, a layer (metal-containing ion layer) composed of this raw material mixture is formed on a support. As the support, the materials and the like exemplified above for the substrate can be used, but those having ultraviolet light shielding properties are preferable in order to suppress unintended photoreduction of metal ions, and for example, aluminum foil is suitable. . Further, as a method of forming the layer, printing,
Coating or the like may be applied. Thus, a laminate for forming a thermosensitive coloring element is formed.

Further, the metal-containing ion layer of this laminate was
Transfer to desired site on substrate. Since this layer has adhesiveness, when the layer is brought into contact with the surface of the substrate and the support is heated and / or pressed from the surface opposite to the substrate, the metal-containing ion layer is easily transferred to the substrate. .

Subsequently, the metal ions are photoreduced. The photoreduction can be performed by irradiating the metal-containing ion layer with ultraviolet rays. By the reduction of the metal ions, the metal-containing ion layer is converted to a color-forming layer. The irradiation amount of the ultraviolet ray may be appropriately selected depending on the desired coloring characteristics. When the support has an ultraviolet light shielding property, it is preferable to remove the support before irradiating the support with ultraviolet light.

Upon irradiation with ultraviolet rays, metal ions are reduced with α-hydrogen-containing alcohol to metal atoms. Depending on the method of ultraviolet irradiation, metal atoms aggregate, for example, 1 to 3
Fine metal particles having a particle size of not more than nm are generated. Not limited to the present embodiment, the ultraviolet irradiation is performed until the unique color of the metal ion (for example, pale yellow in the case of gold ion) completely disappears.
Alternatively, it is preferable to irradiate immediately before that. This is because excessive irradiation causes aggregation of metal fine particles irrespective of an increase in the ambient environmental temperature, and may cause color development due to surface plasmon absorption before use of the device.

In the above step, the metal-containing ion layer is transferred onto the substrate, and then the photoreduction of the metal ions is performed. However, after the photoreduction reaction of the metal ions, the layer is transferred onto the substrate. It may be transferred.

According to the method described above, a thermosensitive coloring element can be manufactured without any particular limitation on the shape and material of the substrate.

(Eighth Embodiment) Hereinafter, another embodiment of a method for manufacturing a thermosensitive coloring device, which is performed via the thermosensitive coloring device forming laminate, will be described.

First, a raw material mixture is prepared in the same manner as in the seventh embodiment. However, in the present embodiment, the solid matrix is not limited to a material having adhesiveness. The raw material mixture may be prepared by a method according to the solid matrix used. For example, as described in the third embodiment, a solid matrix may be prepared by adding a metal compound or the like to a solvent, or a metal compound or the like may be directly added to a liquefied matrix.

Next, as shown in FIG.
A release agent layer 17 is formed thereon, and a layer (metal-containing ion layer) 8 made of the raw material mixture is formed on the release agent layer. The formation of the metal-containing ion layer 8 can be performed by printing, coating, or the like. After the formation, the metal-containing ion layer is appropriately dried.

Examples of the release agent include a silicone release agent, a copolymer of alkyl acrylate and acrylic acid, a copolymer of stearyl methacrylate and acrylonitrile,
Formaldehyde resin containing stearic acid polyester, a mixture of polyoctadecyl vinyl ether and maleic anhydride, vinyl stearate, allyl stearate,
A solution polymer of maleic anhydride and vinyl octadecyl ether, a mixture of N-stearyl polyacrylamide and toluene, solution-polymerized stearyl itaconate, polymonoacetyl itaconate, polymonobehenyl itaconate, N-substituted linear alkyl maleic acid; Copolymers of vinyl comonomers, polyvinyl carbamate release coatings, fluorocarbon copolymer release coatings, amine acid release coatings, and the like can be used. It is preferable to use a silicone release agent because a release liner that can be easily released at a low release rate can be formed.

The amount of the release agent is not particularly limited, but is preferably 10 g / m ² or less.
About 3 g / m ² is more preferable.

Subsequently, as shown in FIG. 8B, an adhesive layer 4 is formed on the metal-containing ion layer. This pressure-sensitive adhesive layer may be formed by printing, coating, or the like using the pressure-sensitive adhesive exemplified above. When a two-component adhesive such as an epoxy resin-based adhesive is used as the pressure-sensitive adhesive layer, the two-component component of the main agent and the curing agent is separated and arranged on the metal-containing ion layer, and is moved to an arbitrary portion. It is preferable to simultaneously perform compression and mixing of the two liquids at the time of pressing. In this manner, a laminate for forming a thermosensitive coloring element, which includes the adhesive layer in addition to the metal-containing ion layer, can be manufactured.

Further, as shown in FIG.
Then, the desired portion of the surface is brought into contact with the adhesive layer 4, and the metal-containing ion layer 8 is transferred from the support 7 to the base 6 by a method involving heating, pressurizing, etc., as in the seventh embodiment. By this step, the metal-containing ion layer 8 is fixed on the base.

Finally, as shown in FIG. 8D, by irradiating the metal-containing ion layer 8 with ultraviolet rays, the metal ions in the metal-containing ion layer are photoreduced to form the color-forming layer 3. Also in this case, the irradiation amount of the ultraviolet ray is arbitrarily selected depending on the desired coloring properties, and when the support has a light-shielding property, it is preferable to peel off the support before the irradiation with the ultraviolet light.

In the above step, the metal-containing ion layer was transferred onto the substrate, and then the metal ions were subjected to photoreduction. However, the photoreduction reaction was carried out to form a coloring layer on the laminate. Thus, the color-forming layer may be transferred onto a substrate.
As a method of reducing metal ions on the thermosensitive coloring element laminate, for example, a method of irradiating ultraviolet rays at a stage where an adhesive layer is not formed as shown in FIG. On the other hand, after forming the adhesive layer as shown in FIG. 8B, the metal ions may be reduced by irradiating the support with ultraviolet rays. In this case, as the support, it is preferable to use a material that can transmit ultraviolet rays to the extent that the metal ions in the metal-containing ion layer can be reduced, for example, a polyethylene film.

According to the method described above, a thermosensitive coloring element can be manufactured without any particular limitation on the shape and material of the substrate.

(Ninth Embodiment) Hereinafter, an embodiment of a thermosensitive coloring element forming laminate having a release layer on an adhesive layer will be described.

As shown in FIG. 9, the laminate for forming a thermosensitive coloring device is composed of a support 7, a metal-containing ion layer 3 formed on the support, and an adhesive layer formed on the metal-containing ion layer. It includes a layer 4, a release agent layer 14 formed on the adhesive layer, and a release liner 13 for supporting the release agent.

The laminate for forming a thermosensitive coloring element has a release layer 10 composed of a release agent layer and a release liner on an adhesive layer, and has a structure suitable for storage until use. This is because if the release layer is disposed on the adhesive layer, the adhesive properties of the adhesive layer can be maintained for a long period of time. When using the laminate, the release liner 13 holding the release agent layer 14 is peeled off, and the surface of the adhesive layer is exposed, and then the surface is adhered to an arbitrary substrate. When such a laminate is prepared, a thermosensitive coloring element can be easily manufactured by transferring a layer to a substrate when necessary.

As the release agent, the materials exemplified above can be used. Further, the material of the release liner is not particularly limited, but paper, a metal film,
Glass, plastic, cellophane and the like can be used.

Such a laminate is obtained by laminating a metal-containing ion layer and an adhesive layer on a support by the method described in the above embodiment, and further applying a release liner on which a release agent layer has been formed in advance. It can be produced by superimposing the layers and applying pressure. Note that the release agent is preferably applied to the release liner so as to have the above arrangement amount.

Irradiation of ultraviolet rays to the metal-containing ion layer may be performed before laminating the release liner, or may be performed through the layer after laminating. For example, when a material having a high transmittance to ultraviolet light such as a polyethylene film is used as the support, metal ions can be reduced even when the support is irradiated with ultraviolet light. However, as described above, the reduction of the metal-containing ion layer may be performed after the layer is transferred to the substrate.

The laminate for forming a thermosensitive coloring element described above is convenient to store when a long laminate is prepared and rolled into a roll. This mode is also preferable for continuously producing a laminate.

In the case of winding in a roll like this,
As shown in FIG. 10, instead of the release layer 10, the other surface of the support (the surface opposite to the surface supporting the metal-containing layer, etc.)
A release agent layer 18 is formed on the surface 19 of the release agent layer 18.
It is preferable that the adhesive layer 20 is wound so that the adhesive layer 20 and the adhesive layer 20 above the adhesive layer 4 adhere to each other. As described above, the ultraviolet irradiation to the thermosensitive coloring element forming laminate can be performed from the release agent layer 18 side by using a material having excellent ultraviolet transmittance such as a polyethylene film as the support. it can.

[0103]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by the following examples.

Example 1 A stock solution of a thermosensitive coloring material having the components shown in Table 1 was prepared.

(Table 1) --------------------------- Matrix forming material Acrylic adhesive 10 ml α-hydrogen-containing alcohol ethylene glycol 20 ml metal ion chloroauric acid 0.05 g −−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−

As the acrylic pressure-sensitive adhesive, a commercially available pressure-sensitive adhesive mainly containing an alkyl acrylate was used.

This stock solution was thinly coated on an aluminum foil as a support, and dried at room temperature to obtain a highly viscous pale yellow metal-containing ion layer having a thickness of 1 mm. The metal-containing ion layer of the laminate for forming a thermosensitive coloring device thus prepared was brought into contact with the surface of the slide glass, and was pressed from the back of the aluminum foil at 50 ° C. for 10 seconds. When the aluminum foil was peeled off after pressing, the metal-containing ion layer was transferred to the surface of the slide glass. Next, the metal-containing ion layer was irradiated with ultraviolet rays of ² mW / cm ² for 5 minutes to photoreduce gold ions. By this photoreduction, the metal-containing ion layer is converted into a coloring layer. Thus, a thermosensitive coloring device using a slide glass as a base was produced. This color-developing layer exhibited a characteristic of developing color in 30 minutes at room temperature and 30 hours at 0 ° C.

Incidentally, an ultraviolet lamp having a wavelength of 254 nm was used for ultraviolet irradiation. This is the same in the following embodiments.

Further, a thermosensitive coloring element was produced in the same manner as above, except that the acrylic pressure-sensitive adhesive was replaced with various pressure-sensitive adhesives. As the adhesive, a natural rubber adhesive, a styrene / butadiene latex adhesive, a thermoplastic rubber block copolymer adhesive, a butyl rubber adhesive, a polyisobutylene adhesive, a vinyl ether polymer adhesive, and a silicone adhesive were used. Although the obtained devices had different adhesive strengths, no significant change was observed in the coloring characteristics.

(Example 2) A silicone-based release agent containing polydimethylsiloxane as a main component was thinly applied in advance to the surface of an aluminum foil, and dried at 60 ° C for 30 minutes to form a release agent layer. When the coating amount of the release agent was about 0.8 g / m ² , the thickness of the release agent layer was about 30 μm.

On this release agent layer, a stock solution having the components shown in Table 1 was applied, dried at room temperature, and dried on an aluminum foil to a thickness of 1%.
A highly viscous pale yellow metal-containing ion layer having a thickness of 1 mm was obtained. This metal-containing ion layer was irradiated with ultraviolet rays of ² mW / cm ² for 5 minutes to photoreduce gold ions, thereby converting this layer into a color-forming layer.

The coloring layer of the laminate for forming a thermosensitive coloring element thus prepared was brought into contact with the surface of the slide glass.
Pressure was applied at 50 ° C. for 10 seconds from the back surface of the aluminum foil as the support. The color transfer layer was transferred to the surface of the slide glass by this pressing. Since the release agent layer was formed on the aluminum foil, the release of the aluminum foil could be performed more easily than in Example 1.

The thermosensitive coloring device obtained by the above method is as follows:
The color developed in 30 minutes at room temperature and 30 hours at 0 ° C.

(Example 3) Instead of aluminum foil, a thickness of 0.5
mm polyethylene film was prepared as a support.
The surface of the polyethylene film was coated with a silicone-based release agent containing polydimethylsiloxane as a main component and dried in the same manner as in Example 2. Also in this case, the coating amount is about 0.8 g / m ^{2 and} the thickness of the release agent layer is 30 μm.
Degree.

The stock solution shown in Table 1 was applied on this release layer, and dried at room temperature.
A highly viscous pale yellow metal-containing ion layer having a thickness of 1 mm was obtained. This metal-containing ion layer was converted into a color-forming layer by irradiating it with ultraviolet rays of ² mW / cm ² for 5 minutes to photoreduce gold ions.

The color-forming layer of the thermosensitive color-forming element-forming laminate was brought into contact with the surface of a slide glass, and pressure was applied at 50 ° C. for 10 seconds from the back of a polyethylene film as a support.
The color transfer layer was transferred to the surface of the slide glass by this pressing. Since the release agent layer was formed on the polyethylene film as the support, the release of the support was easy as in Example 2.

The thermosensitive coloring device obtained by the above method is
The color developed in 30 minutes at room temperature and 30 hours at 0 ° C.

In addition, without peeling the polyethylene film
2 mW / cm through this film ^TwoUV light intensity
Irradiation for 5 minutes and 15 seconds will also increase
It is possible to obtain a thermosensitive coloring element having the same coloring properties as described above.
did it.

Example 4 A stock solution of a thermosensitive coloring material having the components shown in Table 2 was prepared.

(Table 2) --------------------------- Matrix forming material Polyvinyl alcohol 1 g Solvent Water 30 ml α-Hydrogen-containing alcohol Ethylene glycol 20 ml Metal ion Chloroauric acid 0.06 g −−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−

This stock solution was prepared by first mixing polyvinyl alcohol and water, and further adding ethylene glycol and chloroauric acid to the mixed solution.

On the other hand, a thin silicone release agent was previously applied to an aluminum foil serving as a support and dried at 60 ° C. for 30 minutes. After applying the stock solution having the components shown in Table 2, 60
It dried at 1 degreeC for 1 hour, and formed the metal-containing ion layer. A commercially available acrylic pressure-sensitive adhesive was thinly applied on the metal-containing ion layer to form a pressure-sensitive adhesive layer. The amount of the adhesive applied was about 1 g / m ² .

The adhesive layer of the thermosensitive coloring element-forming laminate thus produced was brought into contact with the surface of the slide glass, and lightly pressed at room temperature for 10 seconds. Thereafter, the aluminum foil was peeled off and separated, and further, ultraviolet rays having an intensity of ² mW / cm ² were irradiated to the metal-containing ion layer for 5 minutes, and the gold ions were photoreduced to form a coloring layer.

The thermosensitive coloring device using the slide glass as a substrate obtained by the above method exhibited a property of coloring in 3 hours at room temperature and 120 hours at 0 ° C.

(Example 5) In the same manner as in Example 4, Table 2
An undiluted solution of a thermosensitive coloring material having the following components was applied onto an aluminum foil on which a release agent layer had been formed in advance to form a metal-containing ion layer. Subsequently, the metal-containing ion layer was irradiated with ultraviolet rays of ² mW / cm ² for 5 minutes, and the gold ions were photoreduced to form a coloring layer. Further, an acrylic pressure-sensitive adhesive was thinly applied on the surface of the color-forming layer. The adhesive layer was brought into contact with the surface of the slide glass and lightly pressed at 100 ° C. for 10 seconds.

The thermosensitive coloring element using the slide glass as a substrate obtained by the above method exhibited a property of coloring in 3 hours at room temperature and 120 hours at 0 ° C.

Example 6 A stock solution of a thermosensitive coloring material having the components shown in Table 2 was thinly applied to the surface of a polyethylene film as a support. The application amount was about ² g / cm ² . A drying treatment was performed at 60 ° C. for 1 hour. An acrylic pressure-sensitive adhesive was applied as a pressure-sensitive adhesive layer on the dried metal-containing ion layer. When the coating amount was about 1.0 g / m ² , the thickness of the adhesive layer was about 50 μm. The acrylic pressure-sensitive adhesive was dried at 60 ° C. for 30 minutes after application.

On the other hand, a silicone release agent was thinly applied to the surface of an acrylic paper having a thickness of 1 mm, and dried at 80 ° C. for 30 minutes to form a release layer. 0.8g /
m ² . The release layer and the polyethylene film were pressed and adhered so that the adhesive layer and the release agent layer were in contact with each other.

The laminate for forming a thermosensitive coloring element thus produced was stored at room temperature for one month. One month later, ² mW / cm ² from the polyethylene film side to the metal-containing ion layer.
For 5 minutes to effect photoreduction of gold ions, thereby converting this layer into a color-forming layer. Subsequently, the release layer was peeled off, the adhesive layer of the laminate was brought into close contact with the surface of the slide glass, and lightly pressed from the polyethylene film side to transfer the laminate to the surface of the slide glass.

The thermosensitive coloring device using the slide glass as a substrate obtained by the above method exhibited a property of coloring in 3 hours at room temperature and 120 hours at 0 ° C. The ultraviolet irradiation may be performed from the side on which the adhesive layer is formed after the adhesion of the layer to the slide glass, the transfer, or the separation of the release layer.

(Example 7) Polyethylene having a width of 3 cm and a length of 1 m
Silicon film is peeled off on the surface of
The release agent was applied uniformly and dried at 60 ° C. for 30 minutes. Application
0.8 g / m ^TwoDegree. Next, apply a release agent
The surface shown in Table 2
A thin solution of a heat-sensitive coloring material
An on layer was formed. The coating amount is 10 g / m^TwoDegree.
After the application, a drying treatment was performed at 60 ° C. for 1 hour. continue,
Acrylic as an adhesive layer on the surface of the dried metal-containing ion layer
A lubricating adhesive was applied. The coating amount is 0.5 g / m^TwoDegree and
did. After the application, a drying treatment was performed at 60 ° C. for 30 minutes.
The laminate is irradiated with ultraviolet rays from the release agent layer side to emit gold ions.
Was photoreduced. Irradiation amount is 2mW / cm^Two, During irradiation
The interval was 5 minutes.

One end of the laminated sheet thus formed was fixed to a rod made of aluminum having a radius of 5 cm. The rod was rotated at a rotation speed of once per second so that the sheet was wound. The laminate was concentrically wound around a rod while the adhesive layer of the outer laminate was in close contact with the release agent layer of the inner laminate. The thus wound laminate was immediately cooled to −10 ° C. and stored together with the rod.

After one week, the laminate having a predetermined length was peeled off from the metal bar, the peeled portion was cut, and the pressure-sensitive adhesive layer was brought into contact with the surface of the slide glass and lightly pressed. The adhesive strength of the adhesive layer is
There was almost no change from one week ago, and a thermosensitive coloring device using a slide glass as a base could be manufactured quickly.

The thermosensitive coloring device obtained by the above method was
It showed the property of developing color in 3 hours at room temperature and 120 hours at 0 ° C. It should be noted that a thermosensitive coloring element having similar characteristics could be obtained when the ultraviolet irradiation was performed after the layer was adhered to the slide glass and transferred.

Example 8 A stock solution of a thermosensitive coloring material having the components shown in Table 3 was prepared.

(Table 3) −−−−−−−−−−−−−−−−−−−−−−−−−−− Material name Quantity −−−−−−−−−−−−− −−−−−−−−−−−−−−−−− Matrix forming material Water 50ml α-Hydrogen-containing alcohol Polypropylene glycol 20ml Metal ion Chloroauric acid 0.05g −−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−

The stock solution was stirred at room temperature for 10 minutes. After stirring, the stock solution was cast on a glass plate and cooled in a freezer at -5 ° C to obtain a light yellow solid having a thickness of 1 mm.

This solid was irradiated with ultraviolet rays. 2mW / c
Ultraviolet irradiation was performed for 1 minute at an intensity of m ² . It was confirmed that the gold ions were reduced by ultraviolet irradiation, and the color tone changed from pale yellow to transparent and colorless. From such a change in color tone, it is considered that the particle size of the gold fine particles generated by the reduction is smaller than the particle size of about several nm showing surface plasmon absorption.

The solid was allowed to stand under various temperature conditions and the time required for color development was investigated. Table 5 shows the results. For comparison, the time required until a change in color tone of a device manufactured from the materials shown in Table 4 in the same manner as in Example 10 described later is also shown.

(Table 4) −−−−−−−−−−−−−−−−−−−−−−−−−−−− Material Compounding amount −−−−−−−−−−−−− Α-hydrogen-containing alcohol ethylene glycol 30 ml matrix-forming material tetraethoxysilane 30 ml solvent ethanol 20 ml water 20 ml catalyst hydrochloric acid 1.0 ml metal ion source chloroauric acid 0.06 g −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

(Table 5) Color development time Temperature Material of Table 3 Material of Table 4 ------ −−−−−−−−−−−−−−−−−−−−−−−−−−− 20 ° C. 5 minutes 30 minutes 10 ° C. 5 minutes 4 hours 5 ° C. 5 minutes 9 hours 2 ° C. 6 minutes 14 hours 0 ° C. 10 minutes 21 hours −0.5 ° C. 30 minutes 21 hours −1 ° C. No color development 25 hours −−−−−−−−−−−−−−−−−−−−−−−−−−−−−

As shown in Table 5, at a temperature of 0 ° C. or more, a change in color tone was observed in a short time. In Table 5, a change in color tone occurs even at 0 ° C. or lower, which is the melting point of water.
It is considered to be due to the temperature drop below ℃.

In this example, water was used as the matrix forming material. However, similar effects were obtained when other matrix forming materials were used. Table 6 shows selection examples of the matrix materials, melting points of the respective materials, and times required for the thermosensitive coloring materials prepared using the respective materials in the same manner as described above to develop a color at a predetermined temperature.

(Table 6) Matrix-forming material Melting point (° C.) Time (° C.) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Minutes: The temperature in parentheses is the standing temperature.) --------------------------------------------------------------------------- Water 06 (2 ° C) 4 Silicon bromide 5 10 (10 ° C.) Cyclohexane 75 (10 ° C.) Cyclohexylbenzene 710 (10 ° C.) p-chlorotoluene 720 (10 ° C.) 1,2-dibromoethane 105 (15 ° C.) n-decanol 7 5 (10 ° C.) 1,8-cineole 13 (5 ° C.) Methyl-n-heptylketone-75 (−5 ° C.) Ethyl cinnamate 710 (10 ° C.) Ethylene glycol -1312 (−10 ° C.) Citraconic anhydride 75 (10 ° C) Butyric acid 55 (0 ° C) Dodecylphenol 77 -5 ° C) Nonylphenol -8 5 (-5 ° C) Monoisopananolamine 25 (5 ° C) Tetramethylurea -1 10 (0 ° C) Sulfolane 912 (10 ° C) Hexafluorobenzene 55 (7 ° C) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

As described above, it was confirmed that each thermosensitive coloring material exhibited coloring in a short time at a temperature equal to or higher than the melting point of the matrix forming material.

Further, the stock solution having the components shown in Table 3 is cooled and solidified, placed on a slide glass via an adhesive tape, and further subjected to photoreduction of gold ions by irradiating ultraviolet rays, thereby having the same characteristics. A thermosensitive coloring device was obtained.

(Example 9) A stock solution having the components shown in Table 3 was applied on filter paper and cooled in a freezer at -5 ° C.

The filter paper was irradiated with ultraviolet light of ² mW / cm ² for 1 hour.
Irradiated for minutes. The color tone of the filter paper after ultraviolet irradiation changed from light yellow to transparent and colorless. Table 7 shows the time required for changing the color tone from transparent to purple when the filter paper was left at each temperature condition. For comparison, similarly to Example 8, the time required until the device shown in Table 4 shows a change in color tone of a device manufactured by the same method as in Example 10 described later is also shown.

(Table 7) −−−−−−−−−−−−−−−−−−−−−−−−−− Temperature Materials of Table 3 Materials of Table 4 −−−−−− −−−−−−−−−−−−−−−−−−−−−−−−− 20 ° C. 5 minutes 30 minutes 10 ° C. 7 minutes 4 hours 5 ° C. 10 minutes 9 hours 2 ° C. 13 minutes 14 hours 0 ° C. 15 minutes 21 hours −0.5 ° C. 45 minutes 21 hours −1 ° C. No color development 25 hours −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

As shown in Table 7, it was confirmed that at a temperature of 0 ° C. or higher, the color tone changed in a short time.

Further, an element coated with an inorganic substance such as polyvinyl alcohol and silica gel, a resin and the like after cooling and solidifying the stock solution on the filter paper was also manufactured. Since these substances act as protective layers, migration of the dissolved coloring layer to the outside is prevented. In particular, when a strongly acidic material such as an aqueous solution of chloroauric acid is used and the matrix liquefies during use as in this embodiment, it is preferable to form a protective layer.

(Example 10) A stock solution having the components shown in Table 8 was prepared and stirred for 30 minutes.

(Table 8)------------------------Material-Compounding amount (g)-------------------------------------------------Material Α-Hydrogen-containing alcohol Ethylene glycol 20 Matrix forming material Tetraethoxysilane 30 Solvent Ethanol 20 Water 30 Catalyst Hydrochloric acid 1.0 Metal ion source Chloroauric acid −−−−−−−−−−−−−−−−− 0.06 ---------------------------------------------------------------------------

Next, the stock solution was applied on a filter paper and dried at room temperature for 20 minutes and further in an oven at 60 ° C. for 3 hours. One of the devices fabricated in this manner was designated as device 10-a. Further, after the undiluted solution was dried, the element on which the undiluted solution was applied and dried again was designated as element 10-b.

Both devices were irradiated with ultraviolet rays to perform photoreduction of gold ions. The intensity of the ultraviolet irradiation was ² mW / cm ² . Since the device color tone changed from light yellow to white, irradiation of ultraviolet rays was stopped for 5 minutes.

FIG. 11 and FIG. 1 show the luminance change characteristics when both devices were left under the temperature conditions of 10 ° C., 0 ° C., and −20 ° C.
It is shown in FIG. The vertical axis represents a change in luminance of the element (a higher value indicates a deeper color). The luminance was measured with a luminance meter.

The coloring of the thermosensitive coloring element cannot be observed with the naked eye at the sensitivity as measured by a luminance meter.
Color development cannot be sensed to the naked eye unless a certain level of luminance change occurs. As shown in FIGS. 11 and 12, the time when the luminance change of both elements started to occur was almost equal, but when observed with the naked eye, in the case of a temperature condition of 10 ° C., the element 10-b took 3 hours to confirm color development. Element 10
With -a, color development was confirmed in about one hour.

As described above, from the comparison of the characteristics of the two devices, it was found that the coloring occurred clearly in a short time due to the lamination of a plurality of coloring layers.

Example 11 The procedure described in Example 10 was repeated, except that the filter paper was coated with silica gel or polyvinyl alcohol. Here, the silica gel used was a stock solution having the composition shown in Table 9 which was stirred for 30 minutes. The aqueous solution of polyvinyl alcohol was prepared by dissolving 1 g of resin in 15 ml of water.

(Table 9)--------------------------Material-Compounding amount (g)---------------------------------------------Material −−−−−−−−−−−−−−−−−−−−−−−−−− matrix forming material tetraethoxysilane 30 α-hydrogen-containing alcohol ethylene glycol 20 solvent water 30 catalyst hydrochloric acid 1.0 −−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

The drying treatment of 3 hours described in Example 10 was performed twice each, and the change of the element due to the presence or absence of the surface coating was observed. Table 10 shows the results. Here, the mark “○” indicates that there was no change in the element color tone, and the mark “X” indicates that there was a change during the drying treatment, and that a magenta color was confirmed.

(Table 10)--------------------------------------------------------------------------------------------------------- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− 50 ° C ○ ○ ○ 75 ° C ○ ○ ○ 100 ° C × ○ ○ 125 ° C × ○ ○ 150 ° C × × × −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

As is clear from Table 10, the surface coating improved the resistance of the device to the drying treatment.

[0164]

As described above in detail, according to the present invention, it is possible to provide a thermosensitive coloring material and a thermosensitive coloring element which develop a color even at a low temperature and whose color tone changes irreversibly. It is preferable that such a material or element is applied to temperature control of a cold storage system or the like, since its heat history can be visually recognized by coloring. It is also suitable for checking the heat history of frozen and chilled foods. In particular, if the present invention is applied to foods or the like whose quality deteriorates even in a short time when exposed to a high-temperature atmosphere, it can be checked at a glance whether or not the quality is maintained.

Further, according to the present invention, it is possible to provide a method for efficiently producing a thermosensitive coloring element having such excellent use value and a laminate for forming a thermosensitive coloring element suitable for producing the element. If this laminate is prepared, it is very convenient because a thermosensitive coloring device can be quickly produced when necessary. Further, it is possible to manufacture a thermosensitive coloring element without being changed by the shape of the base or the like. Further, according to the present invention, there is also provided a method for producing such a laminate for forming a thermosensitive coloring device.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a color developing process of a thermosensitive coloring material of the present invention.

FIG. 2 is a cross-sectional view of an example of a molded body made of the thermosensitive coloring material of the present invention.

FIG. 3 is a sectional view of an example of a thermosensitive coloring device of the present invention;
It is a figure which shows the state before coloring (a), and the state after coloring (b).

FIG. 4 is a sectional view of another example of the thermosensitive coloring device of the present invention.

FIG. 5 is a cross-sectional view of another example of the thermosensitive coloring device of the present invention.

FIG. 6 is a cross-sectional view of another example of the thermosensitive coloring device of the present invention.

FIG. 7 is a cross-sectional view of another example of the thermosensitive coloring device of the present invention.

FIG. 8 is a view showing an example of a process of manufacturing the thermosensitive coloring device of the present invention via a thermosensitive coloring device forming laminate.

FIG. 9 is a cross-sectional view illustrating an example of a laminate for forming a thermosensitive coloring element of the present invention.

FIG. 10 is a cross-sectional view showing another example of the thermosensitive coloring element forming laminate of the present invention.

FIG. 11 is a diagram illustrating an example of a change in luminance according to a standing time of the thermosensitive coloring device of the present invention.

FIG. 12 is a diagram showing another example of a change in luminance depending on the standing time of the thermosensitive coloring device of the present invention.

FIG. 13 is a cross-sectional view showing an example of a conventional thermal display element.

DESCRIPTION OF SYMBOLS 1 Solid matrix 2 Metal fine particles 3 Coloring layer 4 Adhesive layer 5 Protective layer 6 Base 7 Support 8 Metal-containing ion layer 10 Release layer 11 Liquefied matrix 12 Metal fine particles with increased particle size 13 Release agent support layer 14 Release agent layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Ohara 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Masatoshi Takao 1006 Okadoma Kadoma Kadoma City Osaka Pref. Terms (reference) 2H026 AA07 BB50 CC10 FF01 FF11 FF13

Claims (36)

[Claims] 1. A solid matrix having an adhesive property, and metal fine particles dispersed in the solid matrix,
A thermosensitive coloring material characterized by exhibiting an irreversible color tone change due to an increase in the particle size of the metal fine particles promoted by the supply of heat from the outside. 2. An adhesive solid matrix comprising a natural rubber adhesive, a styrene / butadiene latex adhesive, a thermoplastic rubber block copolymer adhesive, a butyl rubber adhesive, a polyisobutylene adhesive, an acrylic adhesive, and a vinyl ether. The thermosensitive coloring material according to claim 1, comprising at least one material selected from a polymer-based adhesive and a silicone-based adhesive. 3. An irreversible color tone comprising a solid matrix and metal fine particles dispersed in the solid matrix, wherein when the solid matrix is liquefied by external heat supply, the particle size of the metal fine particles increases. A thermosensitive coloring material characterized by exhibiting a change. 4. The temperature at which the solid matrix liquefies is −
The thermosensitive coloring material according to claim 3, which is at 20C to 20C. 5. The thermosensitive coloring material according to claim 1, comprising at least one metal fine particle selected from gold, platinum, silver, copper, tin, rhodium, palladium and iridium. 6. The thermosensitive coloring material according to claim 1, further comprising metal fine particles generated by photoreduction of metal ions. 7. The method according to claim 1, further comprising metal fine particles having a small particle size that does not exhibit coloration due to surface plasmon absorption.
7. The thermosensitive coloring material according to any one of Items 1 to 6, 8. A color-forming layer comprising a solid matrix in which metal fine particles are dispersed, the color-forming layer exhibiting an irreversible color tone change due to an increase in the particle size of the metal fine particles promoted by external heat supply, and supporting the color-forming layer. A heat-sensitive coloring device, comprising: 9. The thermosensitive coloring device according to claim 8, wherein the thermosensitive coloring material according to claim 3 is contained in a coloring layer. 10. The thermosensitive coloring element according to claim 8, wherein a protective layer is disposed on the coloring layer. 11. A method according to claim 8, wherein at least one selected from an adhesive layer and an adhesive layer is provided between the substrate and the color forming layer.
0. The thermosensitive coloring device according to any one of 0. 12. An adhesive layer comprising a natural rubber-based adhesive, a styrene / butadiene latex-based adhesive, a thermoplastic rubber block copolymer adhesive, a butyl rubber adhesive, a polyisobutylene adhesive, an acrylic adhesive, and a vinyl ether polymer-based adhesive. The thermosensitive coloring device according to claim 11, further comprising at least one material selected from the group consisting of silicone and a silicone-based pressure-sensitive adhesive. 13. The thermosensitive coloring element according to claim 8, wherein the thermosensitive coloring material according to claim 1 is contained in a coloring layer. 14. The color-forming layer according to claim 8, wherein the color-forming layer comprises two or more layers.
A thermosensitive coloring device according to any one of the above. 15. A color-forming layer comprising a solid matrix in which metal fine particles are dispersed and exhibiting an irreversible color tone change due to aggregation of the metal fine particles promoted by external heat supply, and a support for supporting the color-forming layer And a pressure-sensitive adhesive surface for fixing the color-forming layer to a substrate that is a part of the heat-sensitive color-forming element. 16. When a matrix-forming material, a metal ion and an α-hydrogen-containing alcohol are contained and the metal ions are reduced by light irradiation to disperse the metal fine particles in a solid matrix, heat is supplied from outside to promote the reduction. A substrate comprising a metal-containing ion layer exhibiting an irreversible color tone change due to the aggregation of the metal fine particles, and a support for supporting the metal-containing ion layer, wherein the metal-containing ion layer becomes a part of a thermosensitive coloring element A laminate for forming a thermosensitive coloring element, comprising a pressure-sensitive adhesive surface for fixing to a thermosensitive coloring device. 17. The temperature at which the solid matrix liquefies is-
The laminate for forming a thermosensitive coloring element according to claim 15 or 16, wherein the temperature is 20C to 20C. 18. The laminate for forming a thermosensitive coloring element according to claim 15, further comprising an adhesive layer having the adhesive surface. 19. The adhesive layer is made of a natural rubber-based adhesive, a styrene / butadiene latex-based adhesive, a thermoplastic rubber block copolymer adhesive, a butyl rubber adhesive, a polyisobutylene adhesive, an acrylic adhesive, a vinyl ether polymer-based adhesive. 19. The laminate for forming a thermosensitive coloring element according to claim 18, comprising at least one material selected from the group consisting of silicone and a silicone-based adhesive. 20. The laminate for forming a thermosensitive coloring element according to claim 15, wherein the solid matrix has an adhesive property, and the coloring layer or the metal-containing ion layer has an adhesive surface for fixing to the substrate. . 21. The laminate for forming a thermosensitive coloring element according to claim 15, which comprises two or more coloring layers or metal-containing ion layers. 22. The laminate for forming a thermosensitive coloring element according to claim 15, further comprising a release layer on the adhesive surface. 23. The laminate for forming a thermosensitive coloring element according to claim 22, wherein a metal-containing ion layer or a coloring layer, an adhesive layer, and a release layer are laminated in this order on a support. 24. The laminate for forming a thermosensitive coloring element according to claim 22, wherein the release layer includes a release agent layer and a release agent support layer. 25. The method according to claim 1, wherein a release agent layer is provided on the support.
25. The laminate for forming a thermosensitive coloring device according to any one of 5 to 24. 26. A support having an adhesive surface above a first surface supporting a metal-containing ion layer or a color-forming layer, and a release agent on a second surface opposite to the first surface. 26. The laminate for forming a thermosensitive coloring element according to claim 25, further comprising a layer, and wound so that the adhesive surface and the release agent layer are in contact with each other. 27. The laminate for forming a thermosensitive coloring element according to claim 15, wherein a protective layer comprising at least one selected from an inorganic substance and a resin is provided on the support. 28. A method comprising the steps of: preparing a raw material mixture containing a matrix-forming material, metal ions and an α-hydrogen-containing alcohol; and forming a metal-containing ion layer containing the raw material mixture on a support. A method for producing a laminate for forming a thermosensitive coloring element. 29. The method according to claim 28, further comprising the step of forming an adhesive layer on the metal-containing ion layer. 30. The thermosensitive coloring element-forming laminate according to claim 28, further comprising a step of cooling the metal-containing ion layer to a temperature equal to or lower than the melting point of the matrix-forming material after forming the metal-containing ion layer. Production method. 31. The method according to claim 28, wherein a matrix-forming material for imparting tackiness to the metal-containing ion layer is used. 32. The method according to claim 28, further comprising the step of reducing metal ions by irradiating the metal-containing ion layer with light to form a color-forming layer in which metal fine particles are dispersed in a solid matrix.
The method for producing a laminate for forming a thermosensitive coloring element according to any one of the above. 33. The method according to claim 28, further comprising a step of forming a release agent layer on the support before forming the metal-containing ion layer.
33. The method for producing a laminate for forming a thermosensitive coloring element according to any one of Items 32 to 32. 34. A method of manufacturing a thermosensitive coloring element, comprising a step of fixing the thermosensitive coloring element-forming laminate according to any one of claims 15 to 27 on a substrate with an adhesive surface. 35. A thermosensitive coloring element-forming laminate produced by the production method according to claim 28, which is contained in any one layer selected from a coloring layer, a metal-containing layer, and an adhesive layer. A method for producing a thermosensitive coloring element, comprising a step of fixing the thermosensitive coloring element on a substrate with an adhesive surface to be formed. 36. A step of preparing a raw material mixture containing a matrix-forming material, a metal ion and an α-hydrogen-containing alcohol; a step of forming a metal-containing ion layer containing the raw material mixture on a substrate; Reducing the metal ions by irradiating the heat-sensitive coloring element with light.