WO2024142146A1 - Temperature indicator and method for producing temperature indicator - Google Patents

Temperature indicator and method for producing temperature indicator Download PDF

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Publication number
WO2024142146A1
WO2024142146A1 PCT/JP2022/047874 JP2022047874W WO2024142146A1 WO 2024142146 A1 WO2024142146 A1 WO 2024142146A1 JP 2022047874 W JP2022047874 W JP 2022047874W WO 2024142146 A1 WO2024142146 A1 WO 2024142146A1
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temperature
indicator
color
detection material
temperature detection
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PCT/JP2022/047874
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French (fr)
Japanese (ja)
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航平 會田
雅彦 荻野
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株式会社日立産機システム
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Priority to PCT/JP2022/047874 priority Critical patent/WO2024142146A1/en
Publication of WO2024142146A1 publication Critical patent/WO2024142146A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
    • G01K11/12—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
    • G01K11/12—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance
    • G01K11/16—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in colour, translucency or reflectance of organic materials

Definitions

  • the present invention relates to a temperature indicator for checking the temperature history of a temperature detection object and a method for manufacturing the temperature indicator.
  • Fresh foods, frozen foods, vaccines, biopharmaceuticals, and other low-temperature-preserved medicines require a cold chain that keeps them at low temperatures without interruption throughout the production, transportation, and consumption distribution process.
  • shipping containers are often equipped with data loggers that can continuously record time and temperature, making it possible to clarify who is responsible if a product is damaged.
  • one method is to use a temperature indicator rather than a data logger.
  • temperature indicators do not have the same recording accuracy as data loggers, they can be attached to individual products, and the surface becomes stained if the temperature exceeds or falls below a preset temperature, making it possible to know changes in the temperature environment.
  • Patent Document 1 discloses a temperature-indicating material that is irreversible at ambient temperature and changes color through crystal-non-crystal or phase-separation-non-phase separation.
  • the temperature indicators themselves are relatively inexpensive, they have the property of irreversibly changing color when the temperature exceeds or falls below a preset temperature. This means that temperature control is required before using the temperature indicator for product management, for example, when storing or transporting the temperature indicator, which can make it difficult to use the temperature indicator conveniently.
  • the degree of irreversibility required of a temperature indicator varies depending on the product to which it is attached.
  • a temperature indicator that changes color once it has deviated from the set temperature and retains that changed color is required to be completely irreversible.
  • a temperature indicator that changes color in accordance with the accumulation of time and temperature.
  • a temperature indicator is one in which ink, whose viscosity changes with temperature, changes color as it penetrates a penetrating material.
  • the ink alone does not function as a temperature indicator, so the structure is complex, making it difficult to reduce the price.
  • it is difficult to reuse temperature indicators such as those mentioned above.
  • the phenomenon in which an amorphous or supercooled material changes from a decolorized state to a colored state by crystallizing may be applicable as a temperature detection material and temperature indicator. These materials can be initialized by melting at a temperature above their melting point, as they return to a decolorized state even when in a colored state.
  • the phenomenon in which an amorphous or supercooled liquid crystallizes to a colored state occurs as a cumulative effect of time and temperature, so they can be used as TTIs.
  • the crystallization rate has a maximum value in a certain temperature range, and the rate decreases above that temperature. Therefore, in a temperature range near the maximum value and above, the discoloration rate decreases with increasing temperature. In other words, in this temperature range, the consistency between the relationship between the time and temperature at which TTI discolors and the relationship between the time and temperature at which food and medicines deteriorate is lost.
  • the temperature-indicating material disclosed in Patent Document 1 changes color between crystalline and non-crystalline states, so it is expected that the rate of color change will decrease with increasing temperature in a temperature range near or above the maximum value of the crystallization rate.
  • the temperature-sensing material disclosed in Patent Document 2 uses two types of temperature-indicating materials that change color through crystallization, making it possible to adjust the rate at which the color changes. However, it is expected that the rate at which the color changes will decrease with increasing temperature in a temperature range near or above the maximum value of the crystallization rate of one of the temperature-indicating materials.
  • one of the objects of the present invention is to provide a temperature indicator that changes color due to the crystallization phenomenon of an amorphous material, and that, in addition to the mechanism, can detect abnormal heating by a sudden change in color in the high temperature range, and a method for manufacturing the temperature indicator.
  • the temperature indicator of the present invention includes a first temperature detection material that changes color due to the amorphous crystallization phenomenon, and a second temperature detection material that changes color irreversibly within a temperature range that is higher than the glass transition point of the first temperature detection material and lower than the melting point of the first temperature detection material.
  • the temperature indicator manufacturing method of the present invention is a method for manufacturing a temperature indicator including a first temperature sensing material that changes color due to the amorphous crystallization phenomenon, and a second temperature sensing material that changes color irreversibly within a temperature range that is higher than the glass transition point of the first temperature sensing material and lower than the melting point of the first temperature sensing material, and after initializing the color of the first temperature sensing material, and before the first temperature sensing material starts to change color, the second temperature sensing material is applied to a position adjacent to the first temperature sensing material.
  • FIG. 1 is a diagram showing a differential scanning calorimetry curve of a temperature indicator.
  • FIG. 2A is a diagram showing the temperature and time dependence of the crystallinity of a temperature indicating material.
  • FIG. 2B is a graph showing the temperature dependence of the crystallization rate.
  • FIG. 4 is a diagram showing a change in color density of a first temperature detecting material.
  • FIG. 4A is a schematic diagram showing the first temperature detection material in a decolored state.
  • FIG. 4B is a diagram illustrating the first temperature detection material in a color-developed state.
  • FIG. 5A is an optical microscope photograph of a phase-separated structure in a decolorized state.
  • FIG. 5B is an optical microscope photograph of the phase-separated structure in a developed state.
  • FIG. 5A is an optical microscope photograph of a phase-separated structure in a decolorized state.
  • FIG. 5B is an optical microscope photograph of the phase-separated structure in
  • FIG. 6A is a graph showing the temperature dependence of the color change rate of the second temperature detection material.
  • FIG. 6B is a graph showing the temperature dependence of the color change rate of the first temperature detection material and the second temperature detection material.
  • FIG. 7A is a graph showing the relationship between the color density of the second temperature sensing material and temperature.
  • FIG. 7B is a diagram showing the relationship between the color density of the first temperature detection material and the second temperature detection material and the temperature.
  • FIG. 8 is a schematic diagram showing the structure of a temperature indicator.
  • FIG. 9 is a schematic diagram showing the structure of a temperature indicator.
  • FIG. 10 is a schematic diagram showing the configuration of a temperature indicator.
  • FIG. 11A is a photograph showing the time elapsed since a temperature deviation and color density in the temperature indicator of the embodiment.
  • FIG. 11B is a photograph showing the time elapsed since the temperature deviation and the color density in the temperature indicator of the embodiment.
  • FIG. 12 is a graph showing the time dependence of color density of the temperature indicator of the embodiment.
  • FIG. 13A is a photograph showing the temperature dependence of color density in the temperature indicator of the embodiment.
  • FIG. 13B is a photograph showing the temperature dependence of color density in the temperature indicator of the example.
  • FIG. 14 is a graph showing the temperature dependency of the color density of the temperature indicator of the embodiment.
  • FIG. 15A is a photograph showing the change over time in color density of the first temperature detection material of the temperature indicator of the embodiment.
  • FIG. 15B is a photograph showing the change over time in color density of the second temperature detection material of the temperature indicator of the embodiment.
  • Figure 1 shows the differential scanning calorimetry (DSC) curve of a temperature indicator.
  • a temperature indicator is a material that solidifies in an amorphous state without crystallizing when it is melted and then rapidly cooled.
  • the temperature at which the exothermic peak appears depends on the heating rate and the elapsed time. This is because the crystallization phenomenon occurs as a result of the accumulation of temperature and time. If the temperature is raised slowly, the peak appears at a low temperature, and if the temperature is raised quickly, the peak appears at a high temperature, or does not appear at all and the material melts at the melting point Tm.
  • the specific method of determining the crystallization rate is not particularly limited, but for example, it can be calculated by measuring the temperature and time dependence of the crystallization rate using a differential scanning calorimeter (DSC).
  • DSC differential scanning calorimeter
  • the temperature indicator is melted at a temperature equal to or higher than the melting point Tm, and then rapidly cooled at -2000°C/s or the like to a predetermined temperature equal to or lower than the glass transition point Tg.
  • the temperature is then rapidly increased to a predetermined temperature at 2000°C/s or the like, and the temperature is maintained at that temperature for a certain period of time.
  • the crystallization of the amorphous material progresses, and an exothermic peak due to crystallization is detected.
  • the crystallization rate is set according to the detection temperature and detection time requirements as a temperature indicator. For example, if a temperature indicator starts to crystallize after one hour has passed at a certain temperature, it can be used as a material that detects that one hour has passed at that temperature.
  • the color change process of the temperature sensing material is observed using a camera or color difference meter.
  • the method for calculating the color density It is possible to evaluate the color in the RGB or Lab color space using a camera or color difference meter, and calculate the color density from the color difference from a specific color such as white. This makes it possible to measure the time dependence of color density at each temperature as a graph like that shown in Figure 2A. If the time required for the color density to reach, say, half its value is considered to be the time required for discoloration, then the reciprocal of this time can be calculated as a measure of the speed required for discoloration (discoloration speed). Using this method, it is possible to obtain the temperature dependence of the discoloration speed in the form of a graph like that shown in Figure 2B. The temperature dependence of this discoloration speed has almost the same relationship as the temperature dependence of the crystallization speed.
  • FIG. 3 is a diagram showing the change in color density of the temperature indicator of the first temperature indicator according to the embodiment.
  • the vertical axis represents color density
  • the horizontal axis represents temperature.
  • the leuco dye is an electron donating compound, and may be any of those conventionally known as dyes for pressure-sensitive copying paper or thermal recording paper, such as triphenylmethanephthalide, fluoran, phenothiazine, indolylphthalide, leucoauramine, spiropyran, rhodamine lactam, triphenylmethane, triazene, spirophthalane xanthene, naphtholactam, and azomethine.
  • dyes for pressure-sensitive copying paper or thermal recording paper such as triphenylmethanephthalide, fluoran, phenothiazine, indolylphthalide, leucoauramine, spiropyran, rhodamine lactam, triphenylmethane, triazene, spirophthalane xanthene, naphtholactam, and azomethine.
  • the temperature indicating material may be a combination of two or more leuco dyes.
  • the color developer changes the structure of the leuco dye by contacting with the electron-donating leuco dye, thereby causing the leuco dye to change color.
  • the color developer a known color developer used in thermal recording paper, pressure-sensitive copying paper, etc. can be used.
  • leuco dyes and color developers are the materials most susceptible to photodegradation. Since leuco dyes affect the color of the ink, it is better to have high selectivity in response to customer requirements, and the present invention is not limited to these. On the other hand, as long as other properties are equivalent, it is preferable for the color developer to be a material that increases the light resistance of the temperature indicator.
  • Bisphenol compounds such as bisphenol S, 4,4'-biphenol, 4,4'-oxydiphenol, 4,4'-dihydroxydiphenylmethane, 4,4'-(1,3-dimethylbutylidene)diphenol, 4,4'-(2-ethylhexylidene)diphenol, 4,4'-ethylidenebisphenol (bisphenol E), 4,4'-(2-hydroxybenzylidene)bis(2,3,6-trimethylphenol), 1,1'-methylenebis(2-naphthol), tetrabromobisphenol A, and 4-hydroxyphenyl(4'-n-propoxyphenyl)sulfone can be preferably used.
  • the temperature indicator may be one of these color developers, or a combination of two or more of them.
  • the color density of the leuco dye when it develops color can be adjusted by combining color developers.
  • the amount of the color developer used is selected according to the desired color density. For example, it is usually selected within the range of about 0.1 to 100 parts by weight per part by weight of the leuco dye.
  • the decolorizing agent is a compound capable of dissociating the bond between the leuco dye and the color developer, and capable of controlling the color-developing temperature between the leuco dye and the color developer. Generally, in the temperature range in which the leuco dye is in a colored state, the decolorizing agent is solidified in a phase-separated state.
  • the decolorizing agent in the temperature range in which the leuco dye is in a decolorized state, the decolorizing agent is melted or in an amorphous state, and is in a state in which it has the function of dissociating the bond between the leuco dye and the color developer. Therefore, the state change temperature of the decolorizing agent is important for the temperature control of the temperature indicator.
  • a wide variety of materials capable of dissociating the bond between the leuco dye and the developer can be used as the material for the decolorizer.
  • Various materials can be used as the decolorizer as long as they have low polarity, do not exhibit color development to the leuco dye, and have high polarity to the extent that they dissolve the leuco dye and the developer.
  • Representative examples of the materials that can be used include various organic compounds such as hydroxy compounds, ester compounds, peroxy compounds, carbonyl compounds, aromatic compounds, aliphatic compounds, halogen compounds, amino compounds, imino compounds, N-oxide compounds, hydroxylamine compounds, nitro compounds, azo compounds, diazo compounds, azide compounds, ether compounds, oils and fats compounds, sugar compounds, peptide compounds, nucleic acid compounds, alkaloid compounds, and steroid compounds. Specifically, tricaprin, isopropyl myristate, acetic acid, etc.
  • decolorizing agents may be used in combination. By combining decolorizing agents, it is possible to adjust the freezing point, crystallization rate, melting point, and glass transition point.
  • the decolorizing agent used in the temperature indicating material must not crystallize during the quenching process from the temperature at which the decolorizing agent melts, but must become amorphous near the glass transition point. For this reason, a material that is difficult to crystallize is preferable. If the quenching speed is very fast, most materials will form an amorphous state, but considering practicality, it is preferable that the material is difficult to crystallize to the extent that it forms an amorphous state when quenched using a general-purpose cooling device. Furthermore, the most preferable material is one that is difficult to crystallize to the extent that it forms an amorphous state during natural cooling from a molten state above the melting point.
  • the color initialization temperature needs to be high enough that it is unlikely to occur near the control temperature, but considering practicality, it is desirable that the temperature range be within which it can be heated using a general-purpose heating device.
  • the heat resistance of these must also be taken into consideration. Specifically, a temperature between 40°C and 250°C is preferable, and between 60°C and 150°C is most preferable.
  • the phase separation structure 1 uses a matrix material 3 whose melting point is close to that of the temperature indicator 2.
  • the color development start temperature of the temperature indicator 2 is close to the glass transition point of the temperature indicator 2, and since the matrix material 3 does not melt at that temperature, the temperature detection material maintains its solid state during the color change process of the temperature indicator 2.
  • the matrix material 3 also melts. Therefore, when applied to a heating type marking device, the temperature detection material can be melted along with the color initialization of the temperature indicator 2, and the temperature detection material can be ejected and marked by heating to a temperature slightly higher than the initialization temperature.
  • the concentration of the temperature indicator 2 contained in the matrix material 3 is not particularly limited, but it is preferable that the matrix material 3 is contained in an amount of 0.1 to 100 parts by weight per 1 part by weight of the temperature indicator 2.
  • concentration of the matrix material 3 is 100 parts by weight or less per 1 part by weight of the temperature indicator 2, the decrease in visibility as a temperature detection material can be suppressed.
  • concentration of the matrix material 3 equal to or greater than the concentration of the temperature indicator 2, it is possible to suppress the formation of a structure in which the matrix material 3 and the temperature indicator 2 are connected to each other (hereinafter referred to as a co-continuous structure).
  • perchlorate ions are also highly soluble, they are explosive, so it is not practical to use them in ink.
  • Other examples include chlorine, bromine, and iodine ions, but these are undesirable as they tend to corrode metals such as iron and stainless steel when they come into contact with them.
  • the second temperature detection material will discolor at a lower temperature than the temperature at which the function of the discoloration speed of the first temperature detection material increasing with increasing temperature is expressed, and the function as a TTI will be lost. Furthermore, if the discoloration start temperature T2 of the second temperature detection material is higher than the discoloration start temperature Td of the first temperature detection material or the melting point Tm of the thermochromic material, when the food or medicine is exposed to very high temperatures, a temperature range will be created where neither the first nor the second temperature detection material will develop color, making the inclusion of the second temperature detection material less meaningful. Note that the maximum discoloration rate T1 of the first temperature detection material is sometimes referred to as the "maximum color change rate temperature.”
  • the crystallization rate of the first temperature detection material is shown in a graph as in Figure 2B, but some types of temperature indicators have a temperature range where the crystals form a metastable phase (crystals with disordered orientation) and a temperature range where they form a stable phase. For this reason, the crystallization rate may not be a single peak as in Figure 2B, but may be divided into multiple peaks or may appear to be a broad peak (with a gradual rate of change from the maximum value). In particular, at temperatures above the temperature T1 at which the crystallization rate reaches its maximum value, the rate often peaks and gradually decreases. The same is true for the discoloration rate. For this reason, it is advisable to adjust the discoloration start temperature T2 of the second temperature detection material to an appropriate optimum temperature in the vicinity of the maximum value T1 of the discoloration rate of the first temperature detection material, depending on the type of first temperature detection material.
  • the first and second temperature sensing materials may be in contact with each other or may be separated from each other within the substrate. It is also possible to treat the ink as a single type of temperature sensing material by including microcapsules of the first and second temperature sensing materials in the ink.
  • first temperature detection material 1 and the second temperature detection material 6 may be covered with a transparent substrate or a transparent adhesive to prevent the temperature detection material from peeling off from the substrate.
  • a transparent substrate or a transparent adhesive to prevent the temperature detection material from peeling off from the substrate.
  • the color of the first temperature detection material 1 changes, it can be detected that the food or medicine has deviated from the controlled temperature and is beginning to deteriorate. If the color of the second temperature detection material 6 changes, it can be detected that the food or medicine has been exposed to a temperature significantly higher than the controlled temperature.
  • the first temperature detection material 1 can be initialized by heating. Therefore, the temperature indicator 4 can be initialized by selectively heating only the first temperature detection material 1. If a material that cannot be initialized is used for the second temperature detection material 6, it becomes difficult to selectively initialize the first temperature detection material 1 if the first temperature detection material 1 and the second temperature detection material 6 are placed in close positions (so that they are close to each other). On the other hand, it is possible to prevent a third party from easily initializing it (to detect initialization by a third party). In this case, too, it is possible to initialize the temperature indicator by using a heating method that is difficult for a third party to handle, such as fine heating using laser heating.
  • close includes a state in which the two are in contact with each other, and means that the distance between the two is close when there is zero space between them (i.e., a contact state) or when there is a space between them.
  • the distance between the two can be said to be close when it is difficult to selectively heat only one of the two using a heating method other than the above-mentioned fine heating.
  • the distance between the two can be said to be close when it is 40 mm or less.
  • the material of the substrate can be freely selected depending on the function required for the temperature indicator.
  • the initialization temperature of the temperature detection material is most preferably 60°C or more and 150°C or less, when it is assumed that the temperature indicator is initialized, any substrate that has a higher heat resistance than this temperature can be applied regardless of the material.
  • organic materials such as paper and plastic, inorganic materials such as ceramics and metals, and composite materials thereof can be freely selected.
  • the material is selected according to the characteristics required for the temperature indicator, such as high strength, heat resistance, weather resistance, chemical resistance, heat insulation, and conductivity.
  • a seal it is also possible to adhere (label) the object to be detected.
  • the change process can also be observed in the same way when the temperature detection material is covered with a transparent substrate or a transparent adhesive. On the other hand, even if the adhesive is not transparent, if the substrate is transparent, the discoloration process of the temperature detection material can be observed from the outside of the substrate.
  • the substrate There are no limitations on the design of the substrate. It is possible to print information other than the color-changing characteristics of the temperature-sensing material, or to print a color that is useful for inspecting the color of the temperature-sensing material.
  • the substrate may be a layered structure made of several materials.
  • the substrate 5 may be formed to surround the temperature detection material 1. This increases the smoothness of the temperature detection material 1 relative to the substrate 5, reducing the variation in color density of the first temperature detection material 1.
  • the top of the first temperature detection material 1 is covered with a transparent base material.
  • a transparent base material By incorporating an ultraviolet blocking material or the like into this transparent base material and the transparent adhesive 7, it is possible to suppress the photofading of the temperature detection material 1. It is also possible to give the temperature indicator functions other than the discoloration property of the temperature detection material, such as providing a material that loses its transparency upon detecting ultraviolet rays, humidity, oxygen, etc.
  • the second temperature detection material 6 is placed at the top.
  • the second temperature detection material covers the surface where the color of the first temperature detection material is visible, so the second temperature detection material needs to be transparent in its initial state.
  • a transparent heat-sensitive sticker can be preferably used.
  • the second temperature detection material if the position of the second temperature detection material is shifted and the color of the first temperature detection material is visible, there is no problem with the second temperature detection material being a non-transparent heat-sensitive sticker.
  • the temperature indicator can be initialized before the second temperature detection material is applied, the temperature indicator can be initialized by heating just before being applied to food or medicine, and then the second temperature detection material can be applied, so that it can be treated as a temperature indicator that cannot be initialized by third parties thereafter.
  • first temperature detection material Preparation of first temperature detection material
  • the following materials were used: 1 part by weight of 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (CVL manufactured by Yamada Chemical Industry Co., Ltd.) as the leuco dye, 1 part by weight of octyl gallate manufactured by Tokyo Chemical Industry Co., Ltd. as the color developer, 100 parts by weight of Vitamin K4 manufactured by Tokyo Chemical Industry Co., Ltd. as the decolorizer, and 100 parts by weight of Hi-Wax 200P manufactured by Mitsui Chemicals Co., Ltd. as the matrix material.
  • the prepared first temperature detection material was heated to 150° C. using a jet dispenser AeroJet manufactured by Musashi Engineering Co., Ltd., turned into a liquid state, and then discharged onto a substrate. General-purpose coated paper was used as the substrate.
  • Second temperature sensing material and preparation of temperature indicator As the second temperature detection material, a clear thermal label manufactured by Toshiba Tec was used. A temperature indicator was produced by attaching the second temperature detection material to a position adjacent to the first temperature detection material discharged onto the substrate.
  • the maximum color change rate T1 of the first temperature detection material was near 55°C
  • the color change start temperature T2 of the second temperature detection material was between 75°C and 85°C. This confirmed that the relationship T1 ⁇ T2 was established, and that T2 was about 20 to 30°C higher than T1.

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  • Measuring Temperature Or Quantity Of Heat (AREA)

Abstract

This temperature indicator comprises: a first temperature detection material that changes in color due to an amorphous crystallization phenomenon; a second temperature detection material that changes in color irreversibly within a temperature range that is higher than the glass transition point of the first temperature detection material and lower than the melting point of the first temperature detection material; and a substrate on which the first temperature detection material and the second temperature detection material are disposed. The first temperature detection material has a phase separation structure in which a temperature-indicating material containing a leuco dye, a color developer, and a decolorizer is dispersed in a matrix material.

Description

温度インジケータおよび温度インジケータ製造方法Temperature indicator and method for manufacturing the same
　本発明は、温度検知対象の温度履歴の確認等を行うための温度インジケータおよび温度インジケータ製造方法に関する。 The present invention relates to a temperature indicator for checking the temperature history of a temperature detection object and a method for manufacturing the temperature indicator.
　生鮮食品、冷凍食品やワクチン、バイオ医薬品等の低温保存医薬品は、生産、輸送、消費の流通過程の中で、途切れることなく低温に保つコールドチェーンが必要である。実際には、流通時の温度を絶えず測定・記録するため、通常、運送コンテナには時間と温度を連続的に記録可能なデータロガーを搭載した場合が多く、製品にダメージがあればその責任の所在を明らかにすることが可能である。 Fresh foods, frozen foods, vaccines, biopharmaceuticals, and other low-temperature-preserved medicines require a cold chain that keeps them at low temperatures without interruption throughout the production, transportation, and consumption distribution process. In practice, to constantly measure and record the temperature during distribution, shipping containers are often equipped with data loggers that can continuously record time and temperature, making it possible to clarify who is responsible if a product is damaged.
　製品個別の品質を管理する場合は、データロガーではなく、温度インジケータを利用する方法がある。温度インジケータはデータロガーほどの記録精度はないものの、製品個別に貼付け可能であり、あらかじめ設定された温度を上回るか、下回るかした場合に表面が染色されるため、温度環境の変化を知ることが可能である。 When managing the quality of individual products, one method is to use a temperature indicator rather than a data logger. Although temperature indicators do not have the same recording accuracy as data loggers, they can be attached to individual products, and the surface becomes stained if the temperature exceeds or falls below a preset temperature, making it possible to know changes in the temperature environment.
　特に、生鮮食品やバイオ医薬品などの温度と時間に依存して品質劣化が進行する製品の品質を管理する場合は、時間と温度の積算で色が変化するTTI（Time-Temperature　Indicator：時間温度インジケータ）が利用される。 In particular, when managing the quality of products whose quality deterioration is dependent on temperature and time, such as fresh foods and biopharmaceuticals, a time-temperature indicator (TTI), which changes color according to the cumulative time and temperature, is used.
　特許文献１には、環境温度下では不可逆性で、結晶－非結晶または相分離－非相分離で色が変化する示温部材が開示されている。 Patent Document 1 discloses a temperature-indicating material that is irreversible at ambient temperature and changes color through crystal-non-crystal or phase-separation-non-phase separation.
　特許文献２には、温度上昇および温度下降を検知可能であり、機能の初期化が可能な温度検知材料が開示されている。 Patent document 2 discloses a temperature sensing material that can detect temperature increases and decreases and whose functions can be initialized.
特開２０００－１３１１５２号公報JP 2000-131152 A 特開２０１８－１７９８２６号公報JP 2018-179826 A
　温度インジケータそのものは比較的安価ではあるものの、あらかじめ設定された温度を上回るか、下回るかした場合に不可逆的に色が変化するという性質をもつため、温度インジケータを製品管理に使用する前、例えば温度インジケータの保管時や輸送時においても温度管理が必要になり、温度インジケータを簡便に使用することが難しい場合がある。 Although the temperature indicators themselves are relatively inexpensive, they have the property of irreversibly changing color when the temperature exceeds or falls below a preset temperature. This means that temperature control is required before using the temperature indicator for product management, for example, when storing or transporting the temperature indicator, which can make it difficult to use the temperature indicator conveniently.
　一方、温度インジケータに要求される不可逆性の程度は、貼付される製品によっても異なる。高価な医薬品などの場合、偽造防止というニーズもあり、設定温度を逸脱して一旦色変化した後の温度インジケータはその後も変化した色が保持される完全な不可逆性が求められる。しかしながら、安価な医薬品や食品などの品質管理においては、環境温度以下においてなされる流通過程において不可逆性が保たれていれば十分であり、むしろ温度インジケータの管理による手間やコストを引き下げることで温度インジケータの利用を促進することが期待できる。 On the other hand, the degree of irreversibility required of a temperature indicator varies depending on the product to which it is attached. In the case of expensive pharmaceuticals, there is also a need to prevent counterfeiting, and so a temperature indicator that changes color once it has deviated from the set temperature and retains that changed color is required to be completely irreversible. However, in the quality control of inexpensive pharmaceuticals, food, etc., it is sufficient if irreversibility is maintained throughout the distribution process, which takes place at or below ambient temperature, and it is expected that the use of temperature indicators will be promoted by reducing the effort and cost involved in managing them.
　また、前述したように生鮮食品やバイオ医薬品の品質管理に適用するためには、時間と温度の積算で色が変化する温度インジケータが求められる。このような温度インジケータとしては、例えば、温度により粘性が変化するインクが浸透材中を浸透することで色を変化させるものなどが挙げられる。しかしながら、この温度インジケータの場合、インク単体では温度インジケータとしての機能を果たさないため、構造的に複雑になり低価格化が難しいという課題がある。さらに、前述したような温度インジケータの再利用は困難である。 Furthermore, as mentioned above, in order to apply this to the quality control of fresh foods and biopharmaceuticals, there is a demand for a temperature indicator that changes color in accordance with the accumulation of time and temperature. One example of such a temperature indicator is one in which ink, whose viscosity changes with temperature, changes color as it penetrates a penetrating material. However, in the case of this type of temperature indicator, the ink alone does not function as a temperature indicator, so the structure is complex, making it difficult to reduce the price. Furthermore, it is difficult to reuse temperature indicators such as those mentioned above.
　そこで、少なくともロイコ染料、顕色剤および消色剤を含む材料において、非晶質状態や過冷却状態の材料が結晶化することで消色状態から顕色状態に変化する現象について、温度検知材料および温度インジケータとして適用できる可能性がある。これらの材料は、融点以上の温度において融解することで、顕色状態であっても再び消色状態に戻るため、色の初期化が可能である。また、非晶質や過冷却液体が結晶化することで顕色状態になる現象は、時間と温度の積算で生じるため、TTIとして適用が可能である。 Therefore, in materials that contain at least a leuco dye, a developer, and a decolorizer, the phenomenon in which an amorphous or supercooled material changes from a decolorized state to a colored state by crystallizing may be applicable as a temperature detection material and temperature indicator. These materials can be initialized by melting at a temperature above their melting point, as they return to a decolorized state even when in a colored state. In addition, the phenomenon in which an amorphous or supercooled liquid crystallizes to a colored state occurs as a cumulative effect of time and temperature, so they can be used as TTIs.
　TTIを生鮮食品やバイオ医薬品の品質管理に適用する場合、TTIの変色する時間と温度の関係と生鮮食品やバイオ医薬品が品質劣化する時間と温度の関係に一致性を持たせる必要がある。食品や医薬品の品質を評価する際、アレニウス則などに代表される反応速度論的解析が広く用いられる。これによると、温度上昇に対して指数関数的に品質劣化速度が増加する。非晶質の結晶化することで顕色状態になるTTIを用いる場合、ある温度域において、温度上昇に対して指数関数的に結晶化速度が増加する。すなわち、TTIの変色速度は温度上昇に対して指数関数的に増加することになる。そのため、TTIの変色する時間と温度の関係と食品や医薬品が品質劣化する時間と温度の関係に一致性を持たせることが可能である。 When applying TTI to the quality control of fresh foods and biopharmaceuticals, it is necessary to ensure that the relationship between the time and temperature at which TTI discolors and the time and temperature at which fresh foods and biopharmaceuticals deteriorate are consistent. When evaluating the quality of food and pharmaceuticals, reaction kinetic analysis, such as the Arrhenius law, is widely used. According to this, the rate of quality deterioration increases exponentially with increasing temperature. When using TTI, which becomes colored by crystallizing from an amorphous state, the crystallization rate increases exponentially with increasing temperature in a certain temperature range. In other words, the rate of TTI discoloration increases exponentially with increasing temperature. Therefore, it is possible to ensure that the relationship between the time and temperature at which TTI discolors and the time and temperature at which food and pharmaceuticals deteriorate are consistent.
　一方で、結晶化速度はある温度域で極大値を持ち、その温度以上では速度が低下することが知られている。そのため、極大値近傍以上の温度域では、温度上昇に対して変色速度が減少することになる。すなわち、この温度域では、TTIの変色する時間と温度の関係と食品や医薬品が品質劣化する時間と温度の関係の一致性が損なわれてしまう。 On the other hand, it is known that the crystallization rate has a maximum value in a certain temperature range, and the rate decreases above that temperature. Therefore, in a temperature range near the maximum value and above, the discoloration rate decreases with increasing temperature. In other words, in this temperature range, the consistency between the relationship between the time and temperature at which TTI discolors and the relationship between the time and temperature at which food and medicines deteriorate is lost.
　特許文献１に開示された示温部材は、結晶－非結晶で色が変化するため、結晶化速度の極大値近傍以上の温度域では、温度上昇に対して変色速度が減少することが予想される。 The temperature-indicating material disclosed in Patent Document 1 changes color between crystalline and non-crystalline states, so it is expected that the rate of color change will decrease with increasing temperature in a temperature range near or above the maximum value of the crystallization rate.
　特許文献２に開示された温度検知材料は、結晶化により変色する２種の示温材を用いることで、変色速度を調整することが可能であるが、やはり、１種の示温材の結晶化速度の極大値近傍以上の温度域では、温度上昇に対して変色速度が減少することが予想される。 The temperature-sensing material disclosed in Patent Document 2 uses two types of temperature-indicating materials that change color through crystallization, making it possible to adjust the rate at which the color changes. However, it is expected that the rate at which the color changes will decrease with increasing temperature in a temperature range near or above the maximum value of the crystallization rate of one of the temperature-indicating materials.
　発明は上記課題を解決するためになされた。即ち、本発明の目的の一つは、非晶質の結晶化現象により色変化する温度インジケータにおいて、その機構に加えて、高温域において色が急峻に変化することで異常加熱されたことを検知可能な温度インジケータおよび温度インジケータ製造方法を提供することにある。 The invention was made to solve the above problems. That is, one of the objects of the present invention is to provide a temperature indicator that changes color due to the crystallization phenomenon of an amorphous material, and that, in addition to the mechanism, can detect abnormal heating by a sudden change in color in the high temperature range, and a method for manufacturing the temperature indicator.
　上記課題を解決するため本発明の温度インジケータは、非晶質の結晶化現象により色変化する第１温度検知材料と、前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内で不可逆的に色変化する第２温度検知材料と、を含む。 In order to solve the above problems, the temperature indicator of the present invention includes a first temperature detection material that changes color due to the amorphous crystallization phenomenon, and a second temperature detection material that changes color irreversibly within a temperature range that is higher than the glass transition point of the first temperature detection material and lower than the melting point of the first temperature detection material.
　本発明の温度インジケータ製造方法は、非晶質の結晶化現象により色変化する第１温度検知材料と、前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内で不可逆的に色変化する第２温度検知材料と、を含む温度インジケータを製造する温度インジケータ製造方法であって、前記第１温度検知材料の色を初期化した後、前記第１温度検知材料の変色が開始する前に、前記第２温度検知材料を前記第１温度検知材料の近接位置に付与する。 The temperature indicator manufacturing method of the present invention is a method for manufacturing a temperature indicator including a first temperature sensing material that changes color due to the amorphous crystallization phenomenon, and a second temperature sensing material that changes color irreversibly within a temperature range that is higher than the glass transition point of the first temperature sensing material and lower than the melting point of the first temperature sensing material, and after initializing the color of the first temperature sensing material, and before the first temperature sensing material starts to change color, the second temperature sensing material is applied to a position adjacent to the first temperature sensing material.
　本発明によれば、ある温度域において、時間と温度の積算で色が変化することで温度検知可能であり、その温度域以上の温度において、色が急峻に変化することで異常加熱されたことを検知することができる。 According to the present invention, temperature can be detected by a color change that occurs as a result of the accumulation of time and temperature within a certain temperature range, and abnormal heating can be detected by a sudden change in color at temperatures above that temperature range.
図１は示温材の示差走査熱量測定曲線を示す図である。FIG. 1 is a diagram showing a differential scanning calorimetry curve of a temperature indicator. 図２Ａは示温材の結晶化度の温度および時間依存性を示す図である。FIG. 2A is a diagram showing the temperature and time dependence of the crystallinity of a temperature indicating material. 図２Ｂは結晶化速度の温度依存性を示す図である。FIG. 2B is a graph showing the temperature dependence of the crystallization rate. 第１温度検知材料の色濃度変化を示す図である。FIG. 4 is a diagram showing a change in color density of a first temperature detecting material. 図４Ａは第１温度検知材料の消色している状態を模式的に示す図である。FIG. 4A is a schematic diagram showing the first temperature detection material in a decolored state. 図４Ｂは第１温度検知材料の顕色している状態を模式的に示す図である。FIG. 4B is a diagram illustrating the first temperature detection material in a color-developed state. 図５Ａは相分離構造体の消色している状態の光学顕微鏡写真である。FIG. 5A is an optical microscope photograph of a phase-separated structure in a decolorized state. 図５Ｂは相分離構造体の顕色している状態の光学顕微鏡写真である。FIG. 5B is an optical microscope photograph of the phase-separated structure in a developed state. 図６Ａは第２温度検知材料の変色速度の温度依存性を示す図である。FIG. 6A is a graph showing the temperature dependence of the color change rate of the second temperature detection material. 図６Ｂは第１温度検知材料及び第２温度検知材料の変色速度の温度依存性を示す図である。FIG. 6B is a graph showing the temperature dependence of the color change rate of the first temperature detection material and the second temperature detection material. 図７Ａは第２温度検知材料の色濃度と温度との関係を示す図である。FIG. 7A is a graph showing the relationship between the color density of the second temperature sensing material and temperature. 図７Ｂは第１温度検知材料及び第２温度検知材料の色濃度と温度との関係を示す図である。FIG. 7B is a diagram showing the relationship between the color density of the first temperature detection material and the second temperature detection material and the temperature. 図８は温度インジケータの構成を示す模式図である。FIG. 8 is a schematic diagram showing the structure of a temperature indicator. 図９は温度インジケータの構成を示す模式図である。FIG. 9 is a schematic diagram showing the structure of a temperature indicator. 図１０は温度インジケータの構成を示す模式図である。FIG. 10 is a schematic diagram showing the configuration of a temperature indicator. 図１１Ａは実施例の温度インジケータにおける温度逸脱からの経過時間と色濃度を示す写真である。FIG. 11A is a photograph showing the time elapsed since a temperature deviation and color density in the temperature indicator of the embodiment. 図１１Ｂは実施例の温度インジケータにおける温度逸脱からの経過時間と色濃度を示す写真である。FIG. 11B is a photograph showing the time elapsed since the temperature deviation and the color density in the temperature indicator of the embodiment. 図１２は実施例の温度インジケータの色濃度の時間依存性を示すグラフである。FIG. 12 is a graph showing the time dependence of color density of the temperature indicator of the embodiment. 図１３Ａは実施例の温度インジケータにおける色濃度の温度依存性を示す写真である。FIG. 13A is a photograph showing the temperature dependence of color density in the temperature indicator of the embodiment. 図１３Ｂは実施例の温度インジケータにおける色濃度の温度依存性を示す写真である。FIG. 13B is a photograph showing the temperature dependence of color density in the temperature indicator of the example. 図１４は実施例の温度インジケータの色濃度の温度依存性を示すグラフである。FIG. 14 is a graph showing the temperature dependency of the color density of the temperature indicator of the embodiment. 図１５Ａは実施例の温度インジケータの第１温度検知材料の色濃度の時間変化を観察したときの写真である。FIG. 15A is a photograph showing the change over time in color density of the first temperature detection material of the temperature indicator of the embodiment. 図１５Ｂは実施例の温度インジケータの第２温度検知材料の色濃度の時間変化を観察したときの写真である。FIG. 15B is a photograph showing the change over time in color density of the second temperature detection material of the temperature indicator of the embodiment.
　以下、本発明を実施するための形態（以下「実施形態」という）について、適宜図面を参照しながら詳細に説明する。なお、各図において、共通する部分には同一の符号を付し重複した説明を省略する。
<<実施形態>>
　本発明の実施形態に係る温度インジケータについて説明する。本発明の実施形態に係る温度インジケータは、第１温度検知材料と、第２温度検知材料とを含む。
＜第１温度検知材料＞
　第１温度検知材料は、示温材を含む。以下、第１温度検知材料に用いる示温材の構成について図１および図２Ａ及び図２Ｂを用いて説明する。
＜示温材＞
　示温材としては、温度変化（昇温／降温）により色濃度が可逆的に変化する材料を用いる。示温材は、電子供与性化合物であるロイコ染料と、電子受容性化合物である顕色剤と、変色の温度範囲を制御するための消色剤と、を含む。 Hereinafter, a mode for carrying out the present invention (hereinafter referred to as an "embodiment") will be described in detail with reference to the drawings as appropriate. In each drawing, the same reference numerals are given to common parts, and duplicated explanations will be omitted.
<<Embodiment>>
A temperature indicator according to an embodiment of the present invention will now be described. The temperature indicator according to an embodiment of the present invention includes a first temperature sensing material and a second temperature sensing material.
<First temperature sensing material>
The first temperature detection material includes a temperature indicating material. The configuration of the temperature indicating material used in the first temperature detection material will be described below with reference to Figs. 1, 2A and 2B.
<Temperature Indicator>
The temperature indicator is a material whose color density changes reversibly with temperature change (heating up/down). The temperature indicator includes a leuco dye, which is an electron donating compound, a developer, which is an electron accepting compound, and a decolorizer for controlling the temperature range of the color change.
　図１は示温材の示差走査熱量測定（ＤＳＣ）曲線を示す図である。示温材は、融解後に急冷すると結晶化せずに非晶状態のまま凝固する材料である。 Figure 1 shows the differential scanning calorimetry (DSC) curve of a temperature indicator. A temperature indicator is a material that solidifies in an amorphous state without crystallizing when it is melted and then rapidly cooled.
　図１では、降温過程（図の左向き矢印（←））において、結晶化が起こらないため、結晶化による発熱ピークが観察されない。一方、昇温過程（図の右向き矢印（→））において、結晶化による発熱ピークが観察される。この発熱ピークが現れた温度と時間において、結晶化が進行し、示温材の変色が進行する。Ｔｇはガラス転移点であり、Ｔｍは融点である。 In Figure 1, crystallization does not occur during the cooling process (arrow pointing left (←) on the diagram), so no exothermic peak due to crystallization is observed. On the other hand, an exothermic peak due to crystallization is observed during the heating process (arrow pointing right (→) on the diagram). At the temperature and time when this exothermic peak appears, crystallization progresses and the color of the temperature indicator progresses. Tg is the glass transition point, and Tm is the melting point.
　発熱ピークが現れる温度は、昇温速度や経過時間に依存する。これは、結晶化現象が温度と時間の積算により発生するためである。低速で昇温するとピークは低温に現れ、高速で昇温するとピークは高温に現れるか、あるいは現れずに融点Ｔｍで融解する。 The temperature at which the exothermic peak appears depends on the heating rate and the elapsed time. This is because the crystallization phenomenon occurs as a result of the accumulation of temperature and time. If the temperature is raised slowly, the peak appears at a low temperature, and if the temperature is raised quickly, the peak appears at a high temperature, or does not appear at all and the material melts at the melting point Tm.
　各温度での結晶化速度は、Ｔｇ以下の非晶状態から昇温して、融点Ｔｍ以下の一定温度においたときの結晶化度の時間変化により求められる。図２Ａは示温材の結晶化度の温度および時間依存性を示す図である。図２Ａのように、Ｔｇ近傍では結晶化は長時間経過しても進行しないが、Ｔｇより高い温度では温度に依存し短時間で進行するようになる。 The crystallization rate at each temperature is determined by the change in crystallinity over time when the temperature is raised from an amorphous state below Tg and then placed at a constant temperature below the melting point Tm. Figure 2A shows the temperature and time dependence of the crystallinity of a temperature indicator. As shown in Figure 2A, crystallization does not progress even over a long period of time near Tg, but at temperatures higher than Tg, it depends on the temperature and progresses in a short period of time.
　結晶化速度の具体的な求め方としては、特に限定されないが、例えば、示差走査熱量計（DSC）を用いて、結晶化度の温度および時間依存性を測定することから算出することができる。結晶化度の温度および時間依存性の求め方としては、示温材を融点Ｔｍ以上の温度にて融解し、その後ガラス転移点Ｔｇ以下の所定の温度まで、－２０００℃/sなどにて急冷する。その後２０００℃/sなどにて高速に所定の温度まで昇温し、一定時間その温度で保持する。保持した際、非晶質の結晶化が進行することで、結晶化による発熱ピークが検出される。この発熱ピークの熱流束の積算値を結晶化度とみなすと、図２Ａのように、所定の温度での結晶化度の時間依存性を算出することができる。この結晶化度の例えば１／２の値になる時間を結晶化に要する時間とみなすと、この時間の逆数を結晶化に要する速度の尺度（結晶化速度）として算出することができる。このような手法にて、図２Ｂの結晶化速度の温度依存性を求めることが可能である。 The specific method of determining the crystallization rate is not particularly limited, but for example, it can be calculated by measuring the temperature and time dependence of the crystallization rate using a differential scanning calorimeter (DSC). To determine the temperature and time dependence of the crystallization rate, the temperature indicator is melted at a temperature equal to or higher than the melting point Tm, and then rapidly cooled at -2000°C/s or the like to a predetermined temperature equal to or lower than the glass transition point Tg. The temperature is then rapidly increased to a predetermined temperature at 2000°C/s or the like, and the temperature is maintained at that temperature for a certain period of time. When maintained at that temperature, the crystallization of the amorphous material progresses, and an exothermic peak due to crystallization is detected. If the integrated value of the heat flux of this exothermic peak is regarded as the crystallization rate, the time dependence of the crystallization rate at a predetermined temperature can be calculated as shown in Figure 2A. If the time required for the crystallization rate to reach, for example, 1/2 is regarded as the time required for crystallization, the reciprocal of this time can be calculated as a measure of the speed required for crystallization (crystallization rate). With this method, it is possible to determine the temperature dependence of the crystallization rate in Figure 2B.
　図２Ａより、結晶化度が一定値になるまでの時間を導出し、その逆数を速度の尺度（結晶化速度）とすることで、図２Ｂに示すような各温度での結晶化速度と温度の関係を算出することができる。図２Ｂによると、結晶化速度はある温度において極大値Ｔ１を持つことがわかる。 From Figure 2A, the time it takes for the degree of crystallinity to reach a constant value can be derived, and by using the inverse of this as a measure of speed (crystallization rate), the relationship between crystallization rate and temperature at each temperature can be calculated, as shown in Figure 2B. Figure 2B shows that the crystallization rate has a maximum value T1 at a certain temperature.
　結晶化が起こると顕色するため、温度インジケータとしての検知温度と検知時間の要求に合わせて、結晶化速度を設定する。例えば、ある温度で１時間経過した後に結晶化が開始する示温材であれば、その温度にて１時間経過したことを検知する材料として使用可能である。 Since color appears when crystallization occurs, the crystallization rate is set according to the detection temperature and detection time requirements as a temperature indicator. For example, if a temperature indicator starts to crystallize after one hour has passed at a certain temperature, it can be used as a material that detects that one hour has passed at that temperature.
　温度検知材料の顕色速度の具体的な求め方としては、特に限定されないが、例えば、温調機としてペルチェ式冷却加熱ステージを用い、色の検出方法として、カメラやファイバー式色差計を用いることで、測定することができる。色濃度の温度および時間依存性の求め方としては、温度検知材料を融点Ｔｍ以上の温度にて融解し、その後ガラス転移点Ｔｇ以下の所定の温度まで、－３０℃/minなどにて急冷する。その後３０℃/minなどにて高速に所定の温度まで昇温し、一定時間その温度で保持する。保持した際、カメラや色差計などを用いて、温度検知材料の変色過程を観察する。色濃度の算出方法についても特に限定されない。カメラや色差計などにてＲＧＢやＬａｂ色空間での色を評価し、白色などの特定の色からの色差にて色濃度を算出することが可能である。これにより、図２Ａのようなグラフとして、各温度での色濃度の時間依存性が測定可能である。この色濃度の例えば１／２の値になる時間を変色に要する時間とみなすと、この時間の逆数を変色に要する速度の尺度（変色速度）として算出することができる。このような手法にて、図２Ｂのようなグラフとして、変色速度の温度依存性を求めることが可能である。この変色速度の温度依存性は、結晶化速度の温度依存性とほぼ同一の関係性になる。 The specific method for determining the color development speed of the temperature sensing material is not particularly limited, but for example, it can be measured by using a Peltier cooling and heating stage as a temperature controller and a camera or fiber-type color difference meter as a color detection method. To determine the temperature and time dependence of color density, the temperature sensing material is melted at a temperature equal to or higher than the melting point Tm, and then rapidly cooled at -30°C/min or the like to a specified temperature equal to or lower than the glass transition point Tg. The temperature is then rapidly increased to a specified temperature at a rate of 30°C/min or the like, and the temperature is maintained at that temperature for a certain period of time. When the temperature is maintained, the color change process of the temperature sensing material is observed using a camera or color difference meter. There is also no particular limit to the method for calculating the color density. It is possible to evaluate the color in the RGB or Lab color space using a camera or color difference meter, and calculate the color density from the color difference from a specific color such as white. This makes it possible to measure the time dependence of color density at each temperature as a graph like that shown in Figure 2A. If the time required for the color density to reach, say, half its value is considered to be the time required for discoloration, then the reciprocal of this time can be calculated as a measure of the speed required for discoloration (discoloration speed). Using this method, it is possible to obtain the temperature dependence of the discoloration speed in the form of a graph like that shown in Figure 2B. The temperature dependence of this discoloration speed has almost the same relationship as the temperature dependence of the crystallization speed.
　以下、時間と温度の積算で色が変化し、且つ高温での加熱により色の初期化が可能な温度検知材料について説明する。 Below, we will explain a temperature-sensing material whose color changes with the cumulative effect of time and temperature, and whose color can be initialized by heating at high temperatures.
　図３は、実施形態に係る第１温度インジケータの示温材の色濃度変化を示す図である。図３において、縦軸は色濃度、横軸は温度である。 FIG. 3 is a diagram showing the change in color density of the temperature indicator of the first temperature indicator according to the embodiment. In FIG. 3, the vertical axis represents color density, and the horizontal axis represents temperature.
　図３は、示温材の色濃度と温度の関係を示す図である。示温材は、色濃度変化にヒステリシス特性を有する。示温材として、消色剤に結晶化しにくい材料を用いると、示温材の消色開始温度Ｔｄ以上の融解状態であるＰから顕色開始温度Ｔａ以下に急冷させた際、消色剤が顕色剤を取りこんだまま非晶状態を形成して消色状態を保持する。この状態から、昇温過程で、顕色開始温度Ｔａ以上に温度を上げると、消色剤が結晶化して顕色する。したがって、示温材を含む温度インジケータを用いれば、顕色開始温度Ｔａ未満で温度管理するときに、管理範囲を逸脱し、Ｔａ以上の温度に達したか否かを検知することができる。 Figure 3 shows the relationship between the color density of a temperature indicator and temperature. Temperature indicators have hysteresis characteristics in the change in color density. If a material that does not easily crystallize is used as the temperature indicator, the decolorizer will form an amorphous state while incorporating the developer when it is rapidly cooled from a molten state P at or above the decolorization start temperature Td of the temperature indicator to below the color development start temperature Ta, and maintain the decolorized state. If the temperature is raised from this state to above the color development start temperature Ta during the heating process, the decolorizer will crystallize and develop color. Therefore, by using a temperature indicator containing a temperature indicator, when controlling the temperature below the color development start temperature Ta, it is possible to detect whether the temperature has deviated from the control range and reached a temperature of Ta or higher.
　温度インジケータを、商品等の物品の流通時における物品の温度管理等に利用する場合は、色戻りしないことが要求される。流通時に一度温度が上昇し、色が変化したとしても、流通過程で再び温度が降下し、色が元に戻ってしまうと、温度の変化の有無を把握することができないためである。しかしながら、本実施形態に係る示温材は、消色温度Ｔｄ以上に加熱しない限り色戻りしないため、温度環境の変化を知ることが可能である。 When a temperature indicator is used for temperature management of goods such as merchandise during distribution, it is required that the color does not change. Even if the temperature rises once during distribution and the color changes, if the temperature drops again during the distribution process and the color returns to its original state, it will be impossible to know whether the temperature has changed or not. However, the temperature-indicating material of this embodiment does not change color unless it is heated to the decolorization temperature Td or higher, making it possible to know changes in the temperature environment.
　示温材の顕色開始温度Ｔａは、Ｔｇ近傍であり、消色開始温度ＴｄはＴｍ近傍になるため、温度インジケータとしての要求仕様にあわせて、ＴｇとＴｍを設定する。 The color development start temperature Ta of the temperature indicator is close to Tg, and the color disappearance start temperature Td is close to Tm, so Tg and Tm are set according to the required specifications as a temperature indicator.
　次に、示温材を構成するロイコ染料、顕色剤および消色剤について説明する。
（ロイコ染料）
　ロイコ染料は、電子供与性化合物であって、従来、感圧複写紙用の染料や、感熱記録紙用染料として公知のものを利用できる。例えば、トリフェニルメタンフタリド系、フルオラン系、フェノチアジン系、インドリルフタリド系、ロイコオーラミン系、スピロピラン系、ローダミンラクタム系、トリフェニルメタン系、トリアゼン系、スピロフタランキサンテン系、ナフトラクタム系、アゾメチン系等が挙げられる。ロイコ染料の具体例としては、９－（Ｎ－エチル－Ｎ－イソペンチルアミノ）スピロ［ベンゾ［ａ］キサンテン－１２，３’－フタリド］、２－メチル－６－（Ｎｐ－トリル－Ｎ－エチルアミノ）－フルオラン６－（ジエチルアミノ）－２－［（３－トリフルオロメチル）アニリノ］キサンテン－９－スピロ－３’－フタリド、３，３－ビス（ｐ－ジエチルアミノフェニル）－６－ジメチルアミノフタリド、２’－アニリノ－６’－（ジブチルアミノ）－３’－メチルスピロ［フタリド－３，９’－キサンテン］、３－（４－ジエチルアミノ－２－メチルフェニル）－３－（１－エチル－２－メチルインドール－３－イル）－４－アザフタリド、１－エチル－８－［Ｎ－エチル－Ｎ－（４－メチルフェニル）アミノ］－２，２，４－トリメチル－１，２－ジヒドロスピロ［１１Ｈ－クロメノ［２，３－ｇ］キノリン－１１，３’－フタリド］が挙げられる。 Next, the leuco dye, the color developer, and the decolorizer that constitute the temperature indicating material will be described.
(Leuco dye)
The leuco dye is an electron donating compound, and may be any of those conventionally known as dyes for pressure-sensitive copying paper or thermal recording paper, such as triphenylmethanephthalide, fluoran, phenothiazine, indolylphthalide, leucoauramine, spiropyran, rhodamine lactam, triphenylmethane, triazene, spirophthalane xanthene, naphtholactam, and azomethine. Specific examples of leuco dyes include 9-(N-ethyl-N-isopentylamino)spiro[benzo[a]xanthene-12,3'-phthalide], 2-methyl-6-(Np-tolyl-N-ethylamino)-fluoran 6-(diethylamino)-2-[(3-trifluoromethyl)anilino]xanthene-9-spiro-3'-phthalide, 3,3-bis(p-diethylaminophenyl)-6-dimethylaminophthalide, 2'-anilino-6 1-ethyl-8-[N-ethyl-N-(4-methylphenyl)amino]-2,2,4-trimethyl-1,2-dihydrospiro[11H-chromeno[2,3-g]quinoline-11,3'-phthalide].
　示温材は、２種以上のロイコ染料を組み合わせて用いてもよい。
（顕色剤）
　顕色剤は、電子供与性のロイコ染料と接触することで、ロイコ染料の構造を変化させて呈色させるものである。顕色剤としては、感熱記録紙や感圧複写紙等に用いられる顕色剤として公知のものを利用できる。このような顕色剤の具体例としては、４－ヒドロキシ安息香酸ベンジル、２，２′－ビフェノール、１，１－ビス（３－シクロヘキシル－４－ヒドロキシフェニル）シクロヘキサン、２，２－ビス（３－シクロヘキシル－４－ヒドロキシフェニル）プロパン、ビスフェノールＡ、ビスフェノールＦ、ビス（４－ヒドロキシフェニル）スルフィド、パラオキシ安息香酸エステル、没食子酸エステル等のフェノール類等を挙げることができる。顕色剤は、これらに限定されるものではなく、電子受容体でありロイコ染料を変色させることができる化合物であれば用いることができる。また、カルボン酸誘導体の金属塩、サリチル酸およびサリチル酸金属塩、スルホン酸類、スルホン酸塩類、リン酸類、リン酸金属塩類、酸性リン酸エステル類、酸性リン酸エステル金属塩類、亜リン酸類、亜リン酸金属塩類等を用いてもよい。 The temperature indicating material may be a combination of two or more leuco dyes.
(Developer)
The color developer changes the structure of the leuco dye by contacting with the electron-donating leuco dye, thereby causing the leuco dye to change color. As the color developer, a known color developer used in thermal recording paper, pressure-sensitive copying paper, etc. can be used. Specific examples of such color developers include phenols such as 4-hydroxybenzoate benzyl, 2,2'-biphenol, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, bisphenol A, bisphenol F, bis(4-hydroxyphenyl)sulfide, paraoxybenzoic acid ester, and gallic acid ester. The color developer is not limited to these, and any compound that is an electron acceptor and can change the color of the leuco dye can be used. Furthermore, metal salts of carboxylic acid derivatives, salicylic acid and metal salts of salicylic acid, sulfonic acids, sulfonate salts, phosphoric acids, metal salts of phosphates, acidic phosphates, metal salts of acidic phosphates, phosphorous acids, metal phosphites, and the like may be used.
　しかし、消色剤に用いる材料に応じて、顕色剤がロイコ染料を顕色させることができる色濃度が異なる。消色剤が顕色剤を取りこんだまま非晶状態を形成する消色状態、消色剤が結晶化しロイコ染料と顕色剤を結合させる顕色状態、それぞれの色濃度は、顕色剤と消色剤の組み合わせ、およびその比率に依存する。そのため、ロイコ染料と、消色剤として後述するエステル化合物やステロイド化合物との組み合わせにおいて、十分に色濃度が薄い消色状態（消色性）を示し、十分に色濃度が濃い顕色状態（顕色性）を示す顕色剤を選定する必要がある。 However, the color density at which the developer can develop the leuco dye varies depending on the material used for the decolorizer. The decolorizer takes in the developer and forms an amorphous state, while the decolorizer crystallizes to bond the leuco dye and developer. The color density of each state depends on the combination of developer and decolorizer, and their ratio. For this reason, when combining a leuco dye with an ester compound or steroid compound (described below) as a decolorizer, it is necessary to select a developer that shows a decolorizer state with a sufficiently low color density (decolorization ability) and a developed state with a sufficiently high color density (development ability).
　また、色の初期化や加熱式マーキング装置でのマーキング時において、温度検知材料や温度検知インクに用いる示温材の融点以上に加熱されるため、この加熱時に色味の変色等が発生しないための耐熱性が求められる。具体的には、１２０～１８０℃程度の高温加熱時に顕著な退色が生じないことが求められる。加熱式マーキング装置に適用する場合は、インクを液体状態の適正な粘度に長時間保持する必要があるため、１２０～１８０℃程度に数時間～数十時間晒されても顕著な退色が生じないことが求められる。 In addition, when initializing the color or marking with a heating marking device, the temperature detection material or the thermoindicator used in the temperature detection ink is heated above its melting point, so heat resistance is required to prevent discoloration during this heating. Specifically, it is required that no significant fading occurs when heated to high temperatures of around 120 to 180°C. When applied to a heating marking device, the ink needs to be kept at the appropriate viscosity in a liquid state for a long period of time, so it is required that no significant fading occurs even when exposed to temperatures of around 120 to 180°C for several to several tens of hours.
　さらに、インクやインジケータが長時間、屋内照明や屋外光に晒されてもインクが退色しない耐光性も求められる。温度検知材料および温度検知インクに用いられる材料の内、光劣化が最も生じやすい材料として、ロイコ染料と顕色剤が挙げられる。ロイコ染料はインクの色味に影響するため、顧客要求に対する選択性が高い方が良く、本発明では限定されない。一方で、顕色剤は他の特性が同等であれば、示温材の耐光性が高くなる材料が好ましい。 Furthermore, light resistance is required so that the ink and indicator do not fade even when exposed to indoor lighting or outdoor light for long periods of time. Of the materials used in temperature sensing materials and temperature sensing inks, leuco dyes and color developers are the materials most susceptible to photodegradation. Since leuco dyes affect the color of the ink, it is better to have high selectivity in response to customer requirements, and the present invention is not limited to these. On the other hand, as long as other properties are equivalent, it is preferable for the color developer to be a material that increases the light resistance of the temperature indicator.
　上記のため、消色剤である種々のエステル化合物やステロイド化合物に対して高い消色性および顕色性を示し、耐熱性および耐光性が高い顕色剤が求められる。このような顕色剤の具体例としては、２，２′－ビスフェノール、４,４‘－シクロヘキシリデンビス(２－シクロヘキシルフェノール)、２，２－ビス(３－シクロヘキシル－４－ヒドロキシフェニル)プロパン、２，２－ビス(２－ヒドロキシ－５－ビフェニルイル)プロパン、４，４’－シクロヘキシリデンビス(ｏ－クレゾール)、２，２－ビス(４－ヒドロキシ－３－メチルフェニル)プロパン、１，１－ビス(４－ヒドロキシフェニル)シクロヘキサン、ビスフェノールＰ、４，４‘－(９－フルオレニリデン)ジフェノール、ビスフェノールＡ、ビスフェノールＭ、４，４’－チオジフェノール、ビスフェノールＳ、４，４‘－ビフェノール、４，４’－オキシジフェノール、４，４‘－ジヒドロキシジフェニルメタン、４，４’－(１，３-ジメチルブチリデン)ジフェノール、４，４‘－(２－エチルヘキシリデン)ジフェノール、４，４’－エチリデンビスフェノール（ビスフェノールＥ）、４，４‘－(２－ヒドロキシベンジリデン)ビス(２，３，６－トリメチルフェノール)、１，１’－メチレンビス(２－ナフトール)、テトラブロモビスフェノールＡ、４－ヒドロキシフェニル（４’－ｎ－プロポキシフェニル）スルホンなどのビスフェノール化合物を好ましく用いることができる。 For the above reasons, there is a demand for a developer that exhibits high decolorization and color development properties in relation to various decolorizing ester compounds and steroid compounds, and that also has high heat and light resistance. Specific examples of such developers include 2,2'-bisphenol, 4,4'-cyclohexylidenebis(2-cyclohexylphenol), 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(2-hydroxy-5-biphenylyl)propane, 4,4'-cyclohexylidenebis(o-cresol), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bisphenol P, 4,4'-(9-fluorenylidene)diphenol, bisphenol A, bisphenol M, and 4,4'-thiodiphenol. Bisphenol compounds such as bisphenol S, 4,4'-biphenol, 4,4'-oxydiphenol, 4,4'-dihydroxydiphenylmethane, 4,4'-(1,3-dimethylbutylidene)diphenol, 4,4'-(2-ethylhexylidene)diphenol, 4,4'-ethylidenebisphenol (bisphenol E), 4,4'-(2-hydroxybenzylidene)bis(2,3,6-trimethylphenol), 1,1'-methylenebis(2-naphthol), tetrabromobisphenol A, and 4-hydroxyphenyl(4'-n-propoxyphenyl)sulfone can be preferably used.
　示温材は、これらの顕色剤を１種、または、２種類以上組み合わせてもよい。顕色剤を組合せることによりロイコ染料の呈色時の色濃度を調整可能である。本顕色剤の使用量は所望される色濃度に応じて選択する。例えば、通常前記したロイコ色素１重量部に対して、０．１～１００重量部程度の範囲内で選択すればよい。
（消色剤）
　消色剤は、ロイコ染料と顕色剤との結合を解離させることが可能な化合物であり、ロイコ染料と顕色剤との呈色温度を制御できる化合物である。一般的に、ロイコ染料が呈色した状態の温度範囲では、消色剤が相分離した状態で固化している。また、ロイコ染料が消色状態となる温度範囲では、消色剤は融解しているか、非晶状態を形成しており、ロイコ染料と顕色剤との結合を解離させる機能が発揮された状態である。そのため、消色剤の状態変化温度が示温材の温度制御に対して重要になる。 The temperature indicator may be one of these color developers, or a combination of two or more of them. The color density of the leuco dye when it develops color can be adjusted by combining color developers. The amount of the color developer used is selected according to the desired color density. For example, it is usually selected within the range of about 0.1 to 100 parts by weight per part by weight of the leuco dye.
(Decolorizing agent)
The decolorizing agent is a compound capable of dissociating the bond between the leuco dye and the color developer, and capable of controlling the color-developing temperature between the leuco dye and the color developer. Generally, in the temperature range in which the leuco dye is in a colored state, the decolorizing agent is solidified in a phase-separated state. In addition, in the temperature range in which the leuco dye is in a decolorized state, the decolorizing agent is melted or in an amorphous state, and is in a state in which it has the function of dissociating the bond between the leuco dye and the color developer. Therefore, the state change temperature of the decolorizing agent is important for the temperature control of the temperature indicator.
　消色剤の材料としては、ロイコ染料と顕色剤との結合を解離させることが可能である材料を幅広く用いることができる。極性が低くロイコ染料に対して顕色性を示さず、ロイコ染料と顕色剤を溶解させる程度に極性が高ければ、様々な材料が消色剤になり得る。代表的には、ヒドロキシ化合物、エステル化合物、ペルオキシ化合物、カルボニル化合物、芳香族化合物、脂肪族化合物、ハロゲン化合物、アミノ化合物、イミノ化合物、Ｎ－オキシド化合物、ヒドロキシアミン化合物、ニトロ化合物、アゾ化合物、ジアゾ化合物、アジ化合物、エーテル化合物、油脂化合物、糖化合物、ペプチド化合物、核酸化合物、アルカロイド化合物、ステロイド化合物など、多様な有機化合物を用いることができる。具体的には、トリカプリン、ミリスチン酸イソプロピル、酢酸　ｍ－トリル、セバシン酸ジエチル、アジピン酸ジメチル、１，４－ジアセトキシブタン、デカン酸デシル、フェニルマロン酸ジエチル、フタル酸ジイソブチル、くえん酸トリエチル、フタル酸ベンジルブチル、ブチルフタリルブチルグリコラート、Ｎ－メチルアントラニル酸メチル、アントラニル酸エチル、サリチル酸２－ヒドロキシエチル、ニコチン酸メチル、４－アミノ安息香酸ブチル、ｐ－トルイル酸メチル、４－ニトロ安息香酸エチル、フェニル酢酸２－フェニルエチル、けい皮酸ベンジル、アセト酢酸メチル、酢酸ゲラニル、こはく酸ジメチル、セバシン酸ジメチル、オキサル酢酸ジエチル、モノオレイン、パルミチン酸ブチル、ステアリン酸エチル、パルミチン酸メチル、ステアリン酸メチル、酢酸リナリル、フタル酸ジ－ｎ－オクチル、安息香酸ベンジル、ジエチレングリコールジベンゾアート、ｐ－アニス酸メチル、酢酸　ｍ－トリル、けい皮酸シンナミル、プロピオン酸２－フェニルエチル、ステアリン酸ブチル、ミリスチン酸エチル、ミリスチン酸メチル、アントラニル酸メチル、酢酸ネリル、パルミチン酸イソプロピル、４－フルオロ安息香酸エチル、シクランデラート　（異性体混合物）、ブトピロノキシル、２－ブロモプロピオン酸エチル、トリカプリリン、レブリン酸エチル、パルミチン酸ヘキサデシル、酢酸ｔｅｒｔ－ブチル、１，１－エタンジオールジアセタート、しゅう酸ジメチル、トリステアリン、アセチルサリチル酸メチル、ベンザルジアセタート、２－ベンゾイル安息香酸メチル、２、３－ジブロモ酪酸エチル、２－フランカルボン酸エチル、アセトピルビン酸エチル、バニリン酸エチル、イタコン酸ジメチル、３－ブロモ安息香酸メチル、アジピン酸モノエチル、アジピン酸ジメチル、１，４－ジアセトキシブタン、ジエチレングリコールジアセタート、パルミチン酸エチル、テレフタル酸ジエチル、プロピオン酸フェニル、ステアリン酸フェニル、酢酸１－ナフチル、ベヘン酸メチル、アラキジン酸メチル、４－クロロ安息香酸メチル、ソルビン酸メチル、イソニコチン酸エチル、ドデカン二酸ジメチル、ヘプタデカン酸メチル、α－シアノけい皮酸エチル、Ｎ－フェニルグリシンエチル、イタコン酸ジエチル、ピコリン酸メチル、イソニコチン酸メチル、ＤＬ－マンデル酸メチル、３－アミノ安息香酸メチル、４－メチルサリチル酸メチル、ベンジリデンマロン酸ジエチル、ＤＬ－マンデル酸イソアミル、メタントリカルボン酸トリエチル、ホルムアミノマロン酸ジエチル、１，２－ビス（クロロアセトキシ）エタン、ペンタデカン酸メチル、アラキジン酸エチル、６－ブロモヘキサン酸エチル、ピメリン酸モノエチル、乳酸ヘキサデシル、ベンジル酸エチル、メフェンピル－ジエチル、プロカイン、フタル酸ジシクロヘキシル、サリチル酸４－ｔｅｒｔ－ブチルフェニル、４－アミノ安息香酸イソブチル、４－ヒドロキシ安息香酸ブチル、トリパルミチン、１，２－ジアセトキシベンゼン、イソフタル酸ジメチル、フマル酸モノエチル、バニリン酸メチル、３－アミノ－２－チオフェンカルボン酸メチル、エトミデート、クロキントセット－メキシル、ベンジル酸メチル、フタル酸ジフェニル、安息香酸フェニル、４－アミノ安息香酸プロピル、エチレングリコールジベンゾアート、トリアセチン、ペンタフルオロプロピオン酸エチル、３－ニトロ安息香酸メチル、酢酸４－ニトロフェニル、３－ヒドロキシ－２－ナフトエ酸メチル、くえん酸トリメチル、３－ヒドロキシ安息香酸エチル、３－ヒドロキシ安息香酸メチル、トリメブチン、酢酸４－メトキシベンジル、ペンタエリトリトールテトラアセタート、４－ブロモ安息香酸メチル、１－ナフタレン酢酸エチル、５－ニトロ－２－フルアルデヒドジアセタート、４－アミノ安息香酸エチル、プロピルパラベン、１，２，４－トリアセトキシベンゼン、４－ニトロ安息香酸メチル、アセトアミドマロン酸ジエチル、バレタマートブロミド、安息香酸２－ナフチル、フマル酸ジメチル、アジフェニン塩酸塩、４－ヒドロキシ安息香酸ベンジル、４－ヒドロキシ安息香酸エチル、酪酸ビニル、ビタミンＫ４、４－ヨード安息香酸メチル、３、３－ジメチルアクリル酸メチル、没食子酸プロピル、１，４－ジアセトキシベンゼン、メソしゅう酸ジエチル、１，４－シクロヘキサンジカルボン酸ジメチル（ｃｉｓ－，ｔｒａｎｓ－混合物）、１，１，２－エタントリカルボン酸トリエチル、ヘキサフルオログルタル酸ジメチル、安息香酸アミル、３－ブロモ安息香酸エチル、５－ブロモ－２－クロロ安息香酸エチル、フタル酸ビス（２－エチルヘキシル）、アリルマロン酸ジエチル、ブロモマロン酸ジエチル、エトキシメチレンマロン酸ジエチル、エチルマロン酸ジエチル、フマル酸ジエチル、マレイン酸ジエチル、マロン酸ジエチル、フタル酸ジエチル、１，３－アセトンジカルボン酸ジメチル、フタル酸ジメチル、３－アミノ安息香酸エチル、安息香酸エチル、４－（ジメチルアミノ）安息香酸エチル、ニコチン酸エチル、フェニルプロピオル酸エチル、ピリジン－２－カルボン酸エチル、２－ピリジル酢酸エチル、３－ピリジル酢酸エチル、安息香酸メチル、フェニル酢酸エチル、４－ヒドロキシ安息香酸アミル、２，５－ジアセトキシトルエン、４－オキサゾールカルボン酸エチル、１，３，５－シクロヘキサントリカルボン酸トリメチル（ｃｉｓ－，ｔｒａｎｓ－混合物）、３－（クロロスルホニル）－２－チオフェンカルボン酸メチル、ペンタエリトリトールジステアラート、ラウリン酸ベンジル、アセチレンジカルボン酸ジエチル、メタクリル酸フェニル、酢酸ベンジル、グルタル酸ジメチル、２－オキソシクロヘキサンカルボン酸エチル、フェニルシアノ酢酸エチル、１－ピペラジンカルボン酸エチル、ベンゾイルぎ酸メチル、フェニル酢酸メチル、酢酸フェニル、こはく酸ジエチル、トリブチリン、メチルマロン酸ジエチル、しゅう酸ジメチル、１，１－シクロプロパンジカルボン酸ジエチル、マロン酸ジベンジル、４－ｔｅｒｔ－ブチル安息香酸メチル、２－オキソシクロペンタンカルボン酸エチル、シクロヘキサンカルボン酸メチル、４－メトキシフェニル酢酸エチル、４－フルオロベンゾイル酢酸メチル、マレイン酸ジメチル、テレフタルアルデヒド酸メチル、４－ブロモ安息香酸エチル、２－ブロモ安息香酸メチル、２－ヨード安息香酸メチル、３－ヨード安息香酸エチル、３－フランカルボン酸エチル、フタル酸ジアリル、ブロモ酢酸ベンジル、ブロモマロン酸ジメチル、ｍ－トルイル酸メチル、１，３－アセトンジカルボン酸ジエチル、フェニルプロピオル酸メチル、酪酸１－ナフチル、ｏ－トルイル酸エチル、２－オキソシクロペンタンカルボン酸メチル、安息香酸イソブチル、３－フェニルプロピオン酸エチル、マロン酸ジ－ｔｅｒｔ－ブチル、セバシン酸ジブチル、アジピン酸ジエチル、テレフタル酸ジエチル、フタル酸ジプロピル、１，１－エタンジオールジアセタート、アジピン酸ジイソプロピル、フマル酸ジイソプロピル、けい皮酸エチル、２－シアノ－３，３－ジフェニルアクリル酸２－エチルヘキシル、ネオペンチルグリコールジアクリラート、トリオレイン、ベンゾイル酢酸エチル、ｐ－アニス酸エチル、スベリン酸ジエチル、ソルビタントリステアレート、ソルビタンモノステアレート、ステアリン酸アミド、モノステアリン酸グリセロール、ジステアリン酸グリセロール、３－（ｔｅｒｔ－ブトキシカルボニル）フェニルボロン酸、ラセカドトリル、４－［（６－アクリロイルオキシ）ヘキシルオキシ］－４´－シアノビフェニル、２－（ジメチルアミノ）ビニル３－ピリジルケトン、アクリル酸ステアリル、４－ブロモフェニル酢酸エチル、フタル酸ジベンジル、３，５－ジメトキシ安息香酸メチル、酢酸オイゲノール、３，３’－チオジプロピオン酸ジドデシル、酢酸バニリン、炭酸ジフェニル、オキサニル酸エチル、テレフタルアルデヒド酸メチル、４－ニトロフタル酸ジメチル、（４－ニトロベンゾイル）酢酸エチル、ニトロテレフタル酸ジメチル、２－メトキシ－５－（メチルスルホニル）安息香酸メチル、３－メチル－４－ニトロ安息香酸メチル、２，３－ナフタレンジカルボン酸ジメチル、アジピン酸ビス（２－エチルヘキシル）、４´－アセトキシアセトフェノン、ｔｒａｎｓ－３－ベンゾイルアクリル酸エチル、クマリン－３－カルボン酸エチル、ＢＡＰＴＡテトラエチルエステル、２，６－ジメトキシ安息香酸メチル、イミノジカルボン酸ジ－ｔｅｒｔ－ブチル、ｐ－ベンジルオキシ安息香酸ベンジル、３，４，５－トリメトキシ安息香酸メチル、３－アミノ－４－メトキシ安息香酸メチル、ジステアリン酸ジエチレングリコール、３，３’－チオジプロピオン酸ジテトラデシル、４－ニトロフェニル酢酸エチル、４－クロロ－３－ニトロ安息香酸メチル、１，４－ジプロピオニルオキシベンゼン、テレフタル酸ジメチル、４－ニトロけい皮酸エチル、５－ニトロイソフタル酸ジメチル、１，３，５－ベンゼントリカルボン酸トリエチル、Ｎ－（４－アミノベンゾイル）－Ｌ－グルタミン酸ジエチル、酢酸２－メチル－１－ナフチル、７－アセトキシ－４－メチルクマリン、４－アミノ－２－メトキシ安息香酸メチル、４，４’－ジアセトキシビフェニル、５－アミノイソフタル酸ジメチル、１，４－ジヒドロ－２、６－ジメチル－３，５－ピリジンジカルボン酸ジエチル、４，４´－ビフェニルジカルボン酸ジメチル、オクタン酸－４－ベンジルオキシフェニルエチル、ノナン酸－４－ベンジルオキシフェニルエチル、デカン酸－４－ベンジルオキシフェニルエチル、ウンデカン酸－４－ベンジルオキシフェニルエチル、ドデカン酸－４－ベンジルオキシフェニルエチル、トリデカン酸－４－ベンジルオキシフェニルエチル、テトラデカン酸－４－ベンジルオキシフェニルエチル、ペンタデカン酸－４－ベンジルオキシフェニルエチル、ヘキサデカン酸－４－ベンジルオキシフェニルエチル、ヘプタデカン酸－４－ベンジルオキシフェニルエチル、オクタデカン酸－４－ベンジルオキシフェニルエチル、オクタン酸１，１－ジフェニルメチル、ノナン酸１，１－ジフェニルメチル、デカン酸１，１－ジフェニルメチル、ウンデカン酸１，１－ジフェニルメチル、ドデカン酸１，１－ジフェニルメチル、トリデカン酸１，１－ジフェニルメチル、テトラデカン酸１，１－ジフェニルメチル、ペンタデカン酸１，１－ジフェニルメチル、ヘキサデカン酸１，１－ジフェニルメチル、ヘプタデカン酸１，１－ジフェニルメチル、オクタデカン酸１，１－ジフェニルメチルなどのエステル化合物や、コレステロール、コレステリルブロミド、β－エストラジオール、メチルアンドロステンジオール、プレグネノロン、安息香酸コレステロール、酢酸コレステロール、リノール酸コレステロール、パルミチン酸コレステロール、ステアリン酸コレステロール、ｎ－オクタン酸コレステロール、オレイン酸コレステロール、３－クロロコレステン、ｔｒａｎｓ－けい皮酸コレステロール、デカン酸コレステロール、ヒドロけい皮酸コレステロール、ラウリン酸コレステロール、酪酸コレステロール、ぎ酸コレステロール、ヘプタン酸コレステロール、ヘキサン酸コレステロール、こはく酸水素コレステロール、ミリスチン酸コレステロール、プロピオン酸コレステロール、吉草酸コレステロール、フタル酸水素コレステロール、フェニル酢酸コレステロール、クロロぎ酸コレステロール、２，４－ジクロロ安息香酸コレステロール、ペラルゴン酸コ
レステロール、コレステロールノニルカルボナート、コレステロールヘプチルカルボナート、コレステロールオレイルカルボナート、コレステロールメチルカルボナート、コレステロールエチルカルボナート、コレステロールイソプロピルカルボナート、コレステロールブチルカルボナート、コレステロールイソブチルカルボナート、コレステロールアミルカルボナート、コレステロールｎ－オクチルカルボナート、コレステロールヘキシルカルボナート、アリルエストレノール、アルトレノゲスト、９（１０）－デヒドロナンドロロン、エストロン、エチニルエストラジオール、エストリオール、安息香酸エストラジオール、β－エストラジオール１７－シピオナート、１７－吉草酸β－エストラジオール、α－エストラジオール、１７－ヘプタン酸β－エストラジオール、ゲストリノン、メストラノール、２－メトキシ－β－エストラジオール、ナンドロロン、（－）－ノルゲストレル、キネストロール、トレンボロン、チボロン、スタノロン、アンドロステロン、アビラテロン、酢酸アビラテロン、デヒドロエピアンドロステロン、デヒドロエピアンドロステロンアセタート、エチステロン、エピアンドロステロン、１７β－ヒドロキシ－１７－メチルアンドロスタ－１，４－ジエン－３－オン、メチルアンドロステンジオール、メチルテストステロン、Δ９（１１）－メチルテストステロン、１α－メチルアンドロスタン－１７β－オール－３－オン、１７α－メチルアンドロスタン－１７β－オール－３－オン、スタノゾロール、テストステロン、プロピオン酸テストステロン、アルトレノゲスト、１６－デヒドロプレグネノロンアセタート、酢酸１６，１７－エポキシプレグネノロン、１１α－ヒドロキシプロゲステロン、１７α－ヒドロキシプロゲステロンカプロアート、１７α－ヒドロキシプロゲステロン、酢酸プレグネノロン、１７α－ヒドロキシプロゲステロンアセタート、酢酸メゲストロール、酢酸メドロキシプロゲステロン、酢酸プレグネノロン、５β－プレグナン－３α，２０α－ジオール、ブデソニド、コルチコステロン、酢酸コルチゾン、コルチゾン、コルテキソロン、デオキシコルチコステロンアセタート、デフラザコート、酢酸ヒドロコルチゾン、ヒドロコルチゾン、１７－酪酸ヒドロコルチゾン、６α－メチルプレドニゾロン、プレドニゾロン、プレドニゾン、酢酸プレドニゾロン、デオキシコール酸ナトリウム、コール酸ナトリウム、コール酸メチル、ヒオデオキシコール酸メチル、β－コレスタノール、コレステロール－５α，６α－エポキシド、ジオスゲニン、エルゴステロール、β－シトステロール、スチグマステロール、β－シトステロールアセタートなどのステロイド化合物などが挙げられる。ロイコ染料および顕色剤との相溶性の観点から、これらの化合物を含むことが好ましい。勿論、これらの化合物に限定されるものではなく、ロイコ染料と顕色剤との結合を解離させることが可能である材料であれば何でもよい。 A wide variety of materials capable of dissociating the bond between the leuco dye and the developer can be used as the material for the decolorizer. Various materials can be used as the decolorizer as long as they have low polarity, do not exhibit color development to the leuco dye, and have high polarity to the extent that they dissolve the leuco dye and the developer. Representative examples of the materials that can be used include various organic compounds such as hydroxy compounds, ester compounds, peroxy compounds, carbonyl compounds, aromatic compounds, aliphatic compounds, halogen compounds, amino compounds, imino compounds, N-oxide compounds, hydroxylamine compounds, nitro compounds, azo compounds, diazo compounds, azide compounds, ether compounds, oils and fats compounds, sugar compounds, peptide compounds, nucleic acid compounds, alkaloid compounds, and steroid compounds. Specifically, tricaprin, isopropyl myristate, acetic acid, etc. m-Tolyl, diethyl sebacate, dimethyl adipate, 1,4-diacetoxybutane, decyl decanoate, diethyl phenylmalonate, diisobutyl phthalate, triethyl citrate, benzyl butyl phthalate, butyl phthalyl butyl glycolate, methyl N-methylanthranilate, ethyl anthranilate, 2-hydroxyethyl salicylate, methyl nicotinate, butyl 4-aminobenzoate, methyl p-toluate, ethyl 4-nitrobenzoate, 2-phenylethyl phenylacetate, benzyl cinnamate, methyl acetoacetate, geranyl acetate, dimethyl succinate, dimethyl sebacate, diethyl oxalacetate, monoolein, butyl palmitate, ethyl stearate, methyl palmitate, methyl stearate, linalyl acetate, di-n-octyl phthalate, benzyl benzoate, diethylene glycol dibenzoate, methyl p-anisate, acetic acid m-Tolyl, cinnamyl cinnamate, 2-phenylethyl propionate, butyl stearate, ethyl myristate, methyl myristate, methyl anthranilate, neryl acetate, isopropyl palmitate, ethyl 4-fluorobenzoate, cyclandelate (Isomeric mixture), butopyronoxyl, ethyl 2-bromopropionate, tricaprylin, ethyl levulinate, hexadecyl palmitate, tert-butyl acetate, 1,1-ethanediol diacetate, dimethyl oxalate, tristearin, methyl acetylsalicylate, benzal diacetate, methyl 2-benzoylbenzoate, ethyl 2,3-dibromobutyrate, ethyl 2-furancarboxylate, ethyl acetopyruvate, ethyl vanillate, dimethyl itaconate, methyl 3-bromobenzoate, monoethyl adipate, dimethyl adipate, 1,4-diacetoxybutane, diethylene glycol diacetate, ethyl palmitate, diethyl terephthalate, phenyl propionate, phenyl stearate, 1-naphthyl acetate, methyl behenate, methyl arachidate ethyl, 4-chlorobenzoate, methyl sorbate, ethyl isonicotinate, dimethyl dodecanedioate, methyl heptadecanoate, ethyl α-cyanocinnamate, ethyl N-phenylglycine, diethyl itaconate, methyl picolinate, methyl isonicotinate, methyl DL-mandelate, methyl 3-aminobenzoate, methyl 4-methylsalicylate, diethyl benzylidenemalonate, isoamyl DL-mandelate, triethyl methanetricarboxylate, diethyl formaminomalonate, 1,2-bis(chloroacetoxy)ethane, methyl pentadecanoate, ethyl arachidate, ethyl 6-bromohexanoate, monoethyl pimelate, hexadecyl lactate, ethyl benzilate, mefenpyr-diethyl, procaine, dicyclohexyl phthalate, 4-tert-butyl salicylate t-Butylphenyl, isobutyl 4-aminobenzoate, butyl 4-hydroxybenzoate, tripalmitin, 1,2-diacetoxybenzene, dimethyl isophthalate, monoethyl fumarate, methyl vanillate, methyl 3-amino-2-thiophenecarboxylate, etomidate, cloquintocet-mexyl, methyl benzilate, diphenyl phthalate, phenyl benzoate, propyl 4-aminobenzoate, ethylene glycol dibenzoate, triacetin, ethyl pentafluoropropionate, methyl 3-nitrobenzoate, 4-nitrophenyl acetate, methyl 3-hydroxy-2-naphthoate, trimethyl citrate, ethyl 3-hydroxybenzoate, methyl 3-hydroxybenzoate, trimebutine, 4-methoxybenzyl acetate, pentaerythritol tetraacetate ester, methyl 4-bromobenzoate, ethyl 1-naphthaleneacetate, 5-nitro-2-furaldehyde diacetate, ethyl 4-aminobenzoate, propylparaben, 1,2,4-triacetoxybenzene, methyl 4-nitrobenzoate, diethyl acetamidomalonate, valethamate bromide, 2-naphthyl benzoate, dimethyl fumarate, adiphenine hydrochloride, benzyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, vinyl butyrate, vitamin K4, methyl 4-iodobenzoate, methyl 3,3-dimethylacrylate, propyl gallate, 1,4-diacetoxybenzene, diethyl mesooxalate, dimethyl 1,4-cyclohexanedicarboxylate (cis-, trans-mixture), triethyl 1,1,2-ethanetricarboxylate, hexafluoroglutarate Dimethyl ester, amyl benzoate, ethyl 3-bromobenzoate, ethyl 5-bromo-2-chlorobenzoate, bis(2-ethylhexyl) phthalate, diethyl allylmalonate, diethyl bromomalonate, diethyl ethoxymethylenemalonate, diethyl ethylmalonate, diethyl fumarate, diethyl maleate, diethyl malonate, diethyl phthalate, dimethyl 1,3-acetonedicarboxylate, dimethyl phthalate, ethyl 3-aminobenzoate, ethyl benzoate, ethyl 4-(dimethylamino)benzoate, ethyl nicotinate, ethyl phenylpropiolate, ethyl pyridine-2-carboxylate, ethyl 2-pyridylacetate, ethyl 3-pyridylacetate, methyl benzoate, ethyl phenylacetate, amyl 4-hydroxybenzoate, 2,5-diacetoxytoluene, 4-oxazo ethyl 1,3,5-cyclohexanetricarboxylate (cis-, trans-mixture), methyl 3-(chlorosulfonyl)-2-thiophenecarboxylate, pentaerythritol distearate, benzyl laurate, diethyl acetylenedicarboxylate, phenyl methacrylate, benzyl acetate, dimethyl glutarate, ethyl 2-oxocyclohexanecarboxylate, ethyl phenylcyanoacetate, ethyl 1-piperazinecarboxylate, methyl benzoylformate, methyl phenylacetate, phenyl acetate, diethyl succinate, tributyrin, diethyl methylmalonate, dimethyl oxalate, diethyl 1,1-cyclopropanedicarboxylate, dibenzyl malonate, methyl 4-tert-butylbenzoate, ethyl 2-oxocyclopentanecarboxylate , methyl cyclohexanecarboxylate, ethyl 4-methoxyphenylacetate, methyl 4-fluorobenzoylacetate, dimethyl maleate, methyl terephthalaldehyde, ethyl 4-bromobenzoate, methyl 2-bromobenzoate, methyl 2-iodobenzoate, ethyl 3-iodobenzoate, ethyl 3-furancarboxylate, diallyl phthalate, benzyl bromoacetate, dimethyl bromomalonate, methyl m-toluate, diethyl 1,3-acetonedicarboxylate, methyl phenylpropiolate, 1-naphthyl butyrate, ethyl o-toluate, methyl 2-oxocyclopentanecarboxylate, isobutyl benzoate, ethyl 3-phenylpropionate, di-tert-butyl malonate, dibutyl sebacate, diethyl adipate, diethyl terephthalate, dipropyl phthalate, 1,1-ethanediol diacetate, diisopropyl adipate, diisopropyl fumarate, ethyl cinnamate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, neopentyl glycol diacrylate, triolein, ethyl benzoylacetate, ethyl p-anisate, diethyl suberate, sorbitan tristearate, sorbitan monostearate, stearic acid amide, glycerol monostearate, glycerol distearate, 3-(tert-butoxycarbonyl)phenylboronic acid, racecadotril, 4-[(6-acryloyloxy)hexyloxy]-4'-cyanobiphenyl, 2-(dimethylamino)vinyl 3-pyridyl ketone, stearyl acrylate, ethyl 4-bromophenylacetate, dibenzyl phthalate, 3,5 -Methyl dimethoxybenzoate, eugenol acetate, didodecyl 3,3'-thiodipropionate, vanillin acetate, diphenyl carbonate, ethyl oxanilate, methyl terephthalaldehyde, dimethyl 4-nitrophthalate, ethyl (4-nitrobenzoyl)acetate, dimethyl nitroterephthalate, methyl 2-methoxy-5-(methylsulfonyl)benzoate, methyl 3-methyl-4-nitrobenzoate, dimethyl 2,3-naphthalenedicarboxylate, bis(2-ethylhexyl) adipate, 4'-acetoxyacetophenone, ethyl trans-3-benzoylacrylate, ethyl coumarin-3-carboxylate, tetraethyl BAPTA ester, methyl 2,6-dimethoxybenzoate, di-tert-butyl iminodicarboxylate, benzyl p-benzyloxybenzoate, Methyl 3,4,5-trimethoxybenzoate, Methyl 3-amino-4-methoxybenzoate, Diethylene glycol distearate, Ditetradecyl 3,3'-thiodipropionate, Ethyl 4-nitrophenylacetate, Methyl 4-chloro-3-nitrobenzoate, 1,4-dipropionyloxybenzene, Dimethyl terephthalate, Ethyl 4-nitrocinnamate, Dimethyl 5-nitroisophthalate, Triethyl 1,3,5-benzenetricarboxylate, Diethyl N-(4-aminobenzoyl)-L-glutamate, 2-methyl-1-naphthyl acetate, 7-acetoxy-4-methylcoumarin, Methyl 4-amino-2-methoxybenzoate, 4,4'-diacetoxybiphenyl, Dimethyl 5-aminoisophthalate, 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylic acid diethyl benzoate, dimethyl 4,4'-biphenyldicarboxylate, 4-benzyloxyphenylethyl octanoate, 4-benzyloxyphenylethyl nonanoate, 4-benzyloxyphenylethyl decanoate, 4-benzyloxyphenylethyl undecanoate, 4-benzyloxyphenylethyl dodecanoate, 4-benzyloxyphenylethyl tridecanoate, 4-benzyloxyphenylethyl tetradecanoate, 4-benzyloxyphenylethyl pentadecanoate, 4-benzyloxyphenylethyl hexadecanoate, 4-benzyloxyphenylethyl heptadecanoate, 4-benzyloxyphenylethyl octadecanoate, 1,1-diphenylmethyl octanoate, 1,1-diphenylmethyl nonanoate, 1,1-diphenyl decanoate ester compounds such as 1,1-diphenylmethyl, 1,1-diphenylmethyl undecanoate, 1,1-diphenylmethyl dodecanoate, 1,1-diphenylmethyl tridecanoate, 1,1-diphenylmethyl tetradecanoate, 1,1-diphenylmethyl pentadecanoate, 1,1-diphenylmethyl hexadecanoate, 1,1-diphenylmethyl heptadecanoate, and 1,1-diphenylmethyl octadecanoate; cholesterol, cholesteryl bromide, β-estradiol, methylandrostenediol, pregnenolone, cholesterol benzoate, cholesterol acetate, cholesterol linoleate, cholesterol palmitate, cholesterol stearate, cholesterol n-octanoate, cholesterol oleate, 3-chlorocholestene, and cholesterol trans-cinnamate. terol, cholesterol decanoate, cholesterol hydrocinnamate, cholesterol laurate, cholesterol butyrate, cholesterol formate, cholesterol heptanoate, cholesterol hexanoate, cholesterol hydrogen succinate, cholesterol myristate, cholesterol propionate, cholesterol valerate, cholesterol hydrogen phthalate, cholesterol phenylacetate, cholesterol chloroformate, cholesterol 2,4-dichlorobenzoate, cholesterol pelargonate, cholesterol nonyl carbonate, cholesterol heptyl carbonate, cholesterol oleyl carbonate, cholesterol methyl carbonate, cholesterol ethyl carbonate, cholesterol isopropyl carbonate, cholesterol butyl carbonate ester, cholesterol isobutyl carbonate, cholesterol amyl carbonate, cholesterol n-octyl carbonate, cholesterol hexyl carbonate, allylestrenol, altrenogest, 9(10)-dehydronandrolone, estrone, ethinyl estradiol, estriol, estradiol benzoate, β-estradiol 17-cypionate, β-estradiol 17-valerate, α-estradiol, β-estradiol 17-heptanoate, gestrinone, mestranol, 2-methoxy-β-estradiol, nandrolone, (-)-norgestrel, quinestrol, trenbolone, tibolone, stanolone, androsterone, abiraterone, abiraterone acetate, dehydroepiandrosterone, Dehydroepiandrosterone acetate, ethisterone, epiandrosterone, 17β-hydroxy-17-methylandrosta-1,4-dien-3-one, methylandrostenediol, methyltestosterone, Δ9(11)-methyltestosterone, 1α-methylandrostan-17β-ol-3-one, 17α-methylandrostan-17β-ol-3-one, stanozolol, testosterone, testosterone propionate, altrenogest, 16-dehydropregnenolone acetate, 16,17-epoxypregnenolone acetate, 11α-hydroxyprogesterone, 17α-hydroxyprogesterone caproate, 17α-hydroxyprogesterone, pregnenolone acetate, 17α-hydroxyprogesterone acetate Examples of the steroid compounds include steroid compounds such as 5-methyl-1,1-dimethyl-2,2 ... Of course, the present invention is not limited to these compounds, and any material capable of dissociating the bond between the leuco dye and the color developer may be used.
　また、これらの消色剤を１種、または２種類以上組み合わせてもよい。消色剤を組合せることにより、凝固点、結晶化速度、融点、ガラス転移点の調整が可能である。 Furthermore, one or more of these decolorizing agents may be used in combination. By combining decolorizing agents, it is possible to adjust the freezing point, crystallization rate, melting point, and glass transition point.
　示温材に用いる消色剤としては、消色剤が融解している温度から、急冷過程において結晶化せず、ガラス転移点近傍で非晶化する必要がある。そのため、結晶化しにくい材料が好ましい。急冷速度を非常に速くすればほとんどの材料で非晶状態を形成するが、実用性を考慮すると、汎用的な冷却装置による急冷で非晶状態を形成する程度に結晶化にしにくい方が好ましい。さらに最も好ましいのは、融点以上の融解状態から自然に冷却する過程で非晶状態を形成する程度に結晶化しにくい材料が好ましい。この条件として、少なくとも２０℃／分以下の速度でも融点からガラス転移点まで冷却したときに非晶状態を形成する消色剤が好ましく、１℃／分以下の速度でも融点からガラス転移点まで冷却したときに非晶状態を形成する消色剤が最も好ましい。 　The decolorizing agent used in the temperature indicating material must not crystallize during the quenching process from the temperature at which the decolorizing agent melts, but must become amorphous near the glass transition point. For this reason, a material that is difficult to crystallize is preferable. If the quenching speed is very fast, most materials will form an amorphous state, but considering practicality, it is preferable that the material is difficult to crystallize to the extent that it forms an amorphous state when quenched using a general-purpose cooling device. Furthermore, the most preferable material is one that is difficult to crystallize to the extent that it forms an amorphous state during natural cooling from a molten state above the melting point. As a condition for this, a decolorizing agent that forms an amorphous state when cooled from the melting point to the glass transition point at a rate of at least 20°C/min or less is preferable, and a decolorizing agent that forms an amorphous state when cooled from the melting point to the glass transition point at a rate of 1°C/min or less is most preferable.
　示温材の色を初期化するためには、示温材の消色剤の融点以上に温度を上げる必要がある。色の初期化温度としては、管理温度付近では起こりづらい程度に高温である必要があるが、実用性を考慮すると、汎用的な加熱装置により加熱可能な温度域であることが望ましい。また温度検知材料としては、示温材を保護するためにマトリックス材やマイクロカプセルを用いるため、これらの耐熱性も考慮する必要がある。具体的には、４０℃以上２５０℃以下が好ましく、６０℃以上１５０℃以下が最も好ましい。 In order to initialize the color of the temperature indicator, it is necessary to raise the temperature above the melting point of the decolorizer in the temperature indicator. The color initialization temperature needs to be high enough that it is unlikely to occur near the control temperature, but considering practicality, it is desirable that the temperature range be within which it can be heated using a general-purpose heating device. In addition, since matrix materials and microcapsules are used as temperature detection materials to protect the temperature indicator, the heat resistance of these must also be taken into consideration. Specifically, a temperature between 40°C and 250°C is preferable, and between 60°C and 150°C is most preferable.
　示温材には、少なくとも上記のロイコ染料、顕色剤、消色剤を含む。ただし、顕色作用および消色作用を1分子中に含む材料を含む場合、顕色剤および消色剤は無くてもよい。また、結晶化により色が変わる性能が保持されれば、ロイコ染料、顕色剤、消色剤以外の材料を含むこともできる。例えば、ロイコ染料ではない染料や顔料を含むことで、消色時、顕色時の色を変更することが可能である。 The temperature-indicating material contains at least the above-mentioned leuco dye, developer, and decolorizer. However, if it contains a material that contains both developer and decolorizer functions in one molecule, the developer and decolorizer are not necessary. In addition, it can contain materials other than leuco dye, developer, and decolorizer as long as the ability to change color through crystallization is maintained. For example, by containing a dye or pigment that is not a leuco dye, it is possible to change the color when decolorizing or developing.
　示温材を第１温度検知材料に適用するにあたり、示温材を被覆し、分散させる技術が必要になる。具体的には、前記の組み合わせの示温材とマトリックス材を混合することで形成する相分離構造体を少なくとも含むか、示温材をマイクロカプセル化したものを少なくとも含む。その形態の例を以下に示す。
（マトリックス材）
　マトリックス材は、示温材と混合したときに、示温材の顕色性および消色性を損なわない材料である必要がある。そのため、それ自身が顕色性を示さない材料であることが好ましい。このような材料として、電子受容体ではない非極性材料を用いることができる。 When applying a temperature indicator to the first temperature detection material, a technique for coating and dispersing the temperature indicator is required. Specifically, the technique includes at least a phase separation structure formed by mixing the above-mentioned combination of the temperature indicator and a matrix material, or includes at least a microencapsulated temperature indicator. Examples of the form are shown below.
(Matrix material)
The matrix material must be a material that does not impair the color-developing and color-decoloring properties of the temperature-indicating material when mixed with the temperature-indicating material. Therefore, it is preferable that the matrix material is a material that does not exhibit color development by itself. As such a material, a non-polar material that is not an electron acceptor can be used.
　また、マトリックス材中に示温材が分散した相分離構造を形成させるために、マトリックス材としては次の２つの条件を満たす材料を用いる必要がある。２つの条件とは、温度インジケータの使用温度で固体状態であること、ロイコ染料、消色剤、および顕色剤と相溶性の低い材料であること、である。ロイコ染料、顕色剤、消色剤、いずれかの材料がマトリックス材と固溶した状態では、温度検知機能は損なわれてしまうためである。また、使用温度で固体状態のマトリックス材を用いることにより、温度検知材料が取り扱いやすくなる。 In addition, in order to form a phase-separated structure in which the temperature indicator is dispersed within the matrix material, the matrix material must satisfy the following two conditions. The two conditions are that the material must be in a solid state at the operating temperature of the temperature indicator, and that it must have low compatibility with the leuco dye, decolorant, and developer. This is because if the leuco dye, developer, or decolorant is in a solid state with the matrix material, the temperature detection function will be impaired. Furthermore, by using a matrix material that is in a solid state at the operating temperature, the temperature detection material becomes easier to handle.
　以上の条件を満たすマトリックス材としては、ハンセン溶解度パラメーターにより予測される分子間の双極子相互作用によるエネルギーδｐおよび分子間の水素結合によるエネルギーδｈがそれぞれ３以下である材料を好ましく用いることができる。具体的には、極性基を有さない材料、炭化水素のみで構成される材料を好ましく用いることができる。具体的には、パラフィン系、マイクロクリスタリン系、オレフィン系、ポリプロピレン系、ポリエチレン系などのワックスや、プロピレン、エチレン、スチレン、シクロオレフィン、シロキサン、テルペンなどの骨格を多く持つ低分子材料や高分子材料、これらの共重合体などが挙げられる。 As a matrix material that satisfies the above conditions, a material in which the energy δp due to dipole interactions between molecules and the energy δh due to hydrogen bonds between molecules predicted by the Hansen solubility parameters are each 3 or less can be preferably used. Specifically, materials that do not have polar groups and materials composed only of hydrocarbons can be preferably used. Specific examples include waxes such as paraffin, microcrystalline, olefin, polypropylene, and polyethylene, low molecular weight materials and polymeric materials with many skeletons such as propylene, ethylene, styrene, cycloolefin, siloxane, and terpene, and copolymers of these.
　これらの中でも、融点以上で低粘度の融解液になり、融点以下で容易に固体化する材料が取扱い性がよい。また、有機溶媒に溶け、有機溶媒の揮発過程で固体化する材料も取扱い性がよい。具体的には、パラフィンワックス、マイクロクリスタリンワックス、ポリオレフィン、ポリエチレン、ポリプロピレン、シクロオレフィン、ポリスチレン、テルペン樹脂、スチレン樹脂、シリコーン樹脂、シリコーンオイルなどが挙げられる。 Among these, materials that become a low-viscosity molten liquid above their melting point and easily solidify below their melting point are easy to handle. Materials that dissolve in organic solvents and solidify during the evaporation process of the organic solvent are also easy to handle. Specific examples include paraffin wax, microcrystalline wax, polyolefin, polyethylene, polypropylene, cycloolefin, polystyrene, terpene resin, styrene resin, silicone resin, and silicone oil.
　ポリオレフィンとしては、例えば、低分子ポリエチレン、低分子ポリプロピレンなどが挙げられる。ポリオレフィンの分子量および液体状態での粘度は特に限定されないが、液体状態で低粘度であると気泡の内包が少なく成形性がよい。具体的には、分子量５万以下であって、融点近傍での粘度が５～５００００ｍＰａ・ｓであることが好ましく、分子量１万以下であって、融点近傍での粘度が１０～１００００ｍＰａ・ｓであることがさらに好ましい。 Examples of polyolefins include low molecular weight polyethylene and low molecular weight polypropylene. There are no particular limitations on the molecular weight of the polyolefin and its viscosity in liquid state, but a low viscosity in liquid state results in fewer air bubbles being included and good moldability. Specifically, it is preferable for the molecular weight to be 50,000 or less and for the viscosity near the melting point to be 5 to 50,000 mPa·s, and it is even more preferable for the molecular weight to be 10,000 or less and for the viscosity near the melting point to be 10 to 10,000 mPa·s.
　また、これらのマトリックス材は、複数種を併用することも可能である。 It is also possible to use multiple types of these matrix materials in combination.
　また、使用温度において液体状態である材料でも、示温材と相分離構造を示せば、マトリックス材として用いることが可能である。マトリックス材が高粘度の液体であれば、固体状態のマトリックス材と同様に取り扱い性に優れる。しかしながら、マトリックス材が高粘度の場合でも、長期間の使用においてマトリックス材中の示温材の沈降・凝集は避けられず、最終的には２相に分離してしまう。そのため、温度検知材料としての長期安定性は低くなる。
＜相分離構造体＞
　図４Ａ及び図４Ｂは、第１温度検知材料の相分離構造を示す模式図であり、図４Ａは消色している状態の場合、図４Ｂは顕色している状態の場合である。相分離構造体１（第１温度検知材料１）は、マトリックス材３中に示温材２が分散した構造を形成している。 In addition, even if the material is in a liquid state at the operating temperature, it can be used as a matrix material if it exhibits a phase-separated structure with the temperature indicator. If the matrix material is a high-viscosity liquid, it is easy to handle, just like a solid matrix material. However, even if the matrix material is highly viscous, sedimentation and aggregation of the temperature indicator in the matrix material cannot be avoided during long-term use, and it will eventually separate into two phases. Therefore, the long-term stability as a temperature detection material will be low.
<Phase-separated structure>
4A and 4B are schematic diagrams showing the phase-separated structure of the first temperature detection material, where Fig. 4A shows the phase-separated structure in a decolorized state and Fig. 4B shows the phase-separated structure in a color-developed state. The phase-separated structure 1 (first temperature detection material 1) forms a structure in which a temperature indicator 2 is dispersed in a matrix material 3.
　図５Ａ及び図５Ｂは、第１温度検知材料の光学顕微鏡写真であり、図５Ａは消色している状態の場合、図５Ｂは顕色している状態の場合である。光学顕微鏡写真から、相分離構造体１について、マトリックス材３中に示温材２が分散した構造を形成していることが確認できる。 FIGS. 5A and 5B are optical microscope photographs of the first temperature detection material, with FIG. 5A showing the material in a decolorized state and FIG. 5B showing the material in a developed state. From the optical microscope photographs, it can be seen that the phase separation structure 1 forms a structure in which the temperature indicator 2 is dispersed in the matrix material 3.
　相分離構造体１は、マトリックス材３の融点が示温材２の融点と近いものを用いている。示温材２の顕色開始温度は示温材２のガラス転移点近傍であり、その温度においてマトリックス材３は融解しないため、示温材２の変色過程において温度検知材料は固体状態を保持する。一方で、示温材２が融点以上において固体から液体に状態変化し、色の初期化が生じる際、マトリックス材３も融解する。そのため、加熱式マーキング装置に適用する際など、示温材２の色の初期化とともに温度検知材料を融解することができ、初期化温度よりわずかに高い温度に加熱することで温度検知材料を吐出、マーキングすることが可能である。 The phase separation structure 1 uses a matrix material 3 whose melting point is close to that of the temperature indicator 2. The color development start temperature of the temperature indicator 2 is close to the glass transition point of the temperature indicator 2, and since the matrix material 3 does not melt at that temperature, the temperature detection material maintains its solid state during the color change process of the temperature indicator 2. On the other hand, when the temperature indicator 2 changes state from solid to liquid above its melting point and color initialization occurs, the matrix material 3 also melts. Therefore, when applied to a heating type marking device, the temperature detection material can be melted along with the color initialization of the temperature indicator 2, and the temperature detection material can be ejected and marked by heating to a temperature slightly higher than the initialization temperature.
　一方で、マトリックス材３の融点が示温材２の融点と離れた温度のものを用いても問題ない。例えば、マトリックス材３の融点が示温材２の融点よりも高い場合、示温材２が固体から液体に状態変化し、色の初期化が生じる際、マトリックス材３が融解しないため、温度検知材料は固体状態を保持することが可能である。 On the other hand, there is no problem if the melting point of the matrix material 3 is different from that of the temperature-indicating material 2. For example, if the melting point of the matrix material 3 is higher than that of the temperature-indicating material 2, when the temperature-indicating material 2 changes state from solid to liquid and the color is initialized, the matrix material 3 does not melt, and the temperature detection material can maintain its solid state.
　また、マトリックス材３と示温材２とは相分離しており、且つマトリックス材３が示温材の色変化に影響を与えないことから、示温材２の温度検知機能をそのまま保持することが可能である。 In addition, since the matrix material 3 and the temperature indicator 2 are phase-separated and the matrix material 3 does not affect the color change of the temperature indicator, it is possible to maintain the temperature detection function of the temperature indicator 2.
　マトリックス材３中に内包する示温材２の濃度は特に限定されないが、示温材２:１重量部に対して、マトリックス材３を０．１重量部以上１００重量部以下含むことが好ましい。示温材２：１重量部に対するマトリックス材３の濃度が１００重量部以下であると、温度検知材料としての視認性の低下を抑制できる。また、マトリックス材３の濃度を、示温材２の濃度と同等以上とすることにより、マトリックス材３および示温材２のそれぞれが繋がりあった構造（以下、共連続構造という。）になるのを抑制することができる。共連続構造でもマトリックス材３と示温材２とは相分離しているため、温度検知材料としての機能は損なわれないが、マトリックス材３中から示温材２が液漏れすることで長期安定性を損なう恐れがある。また、示温材２が結晶化する際、隣接する示温材２間にて結晶成長が進展してしまい、顕色時間の再現性の低下や色ムラ発生のリスクが高まることが懸念される。そのため、示温材２：１重量部に対して、マトリックス材３は１重量部以上１０重量部以下にすることがさらに好ましい。 The concentration of the temperature indicator 2 contained in the matrix material 3 is not particularly limited, but it is preferable that the matrix material 3 is contained in an amount of 0.1 to 100 parts by weight per 1 part by weight of the temperature indicator 2. When the concentration of the matrix material 3 is 100 parts by weight or less per 1 part by weight of the temperature indicator 2, the decrease in visibility as a temperature detection material can be suppressed. In addition, by making the concentration of the matrix material 3 equal to or greater than the concentration of the temperature indicator 2, it is possible to suppress the formation of a structure in which the matrix material 3 and the temperature indicator 2 are connected to each other (hereinafter referred to as a co-continuous structure). Even in a co-continuous structure, the matrix material 3 and the temperature indicator 2 are phase-separated, so the function as a temperature detection material is not impaired, but there is a risk that the temperature indicator 2 will leak from the matrix material 3, thereby impairing long-term stability. In addition, when the temperature indicator 2 crystallizes, crystal growth progresses between adjacent temperature indicators 2, which is a concern as it may reduce the reproducibility of the color development time and increase the risk of color unevenness. Therefore, it is more preferable to use 1 part by weight or more of matrix material 3 and 10 parts by weight or less for each 1 part by weight of temperature indicator material 2.
　マトリックス材３中に分散した示温材２からなる相の長径は、１００ｎｍ以上１ｍｍ以下であることが好ましく、１００ｎｍ以上１００μｍ以下であることがより好ましい。示温材２からなる相の大きさは特に限定されないが、１００ｎｍ以上とすることにより示温材２とマトリックス材３の界面による検知温度への影響を抑制できる。また、１ｍｍ以下とすることにより、示温材２とマトリックス材３とを区別して視認することが困難となり、温度検知材料の色ムラを抑えることができる。示温材２からなる相の大きさは、界面活性剤を添加することや冷却工程において攪拌しながら冷却することにより、小さくすることができる。なお、示温材２からなる相の長径とは、示温材２からなる相を楕円に近似したときの近似楕円の長径である。 The major axis of the phase consisting of the temperature indicator 2 dispersed in the matrix material 3 is preferably 100 nm or more and 1 mm or less, and more preferably 100 nm or more and 100 μm or less. The size of the phase consisting of the temperature indicator 2 is not particularly limited, but by making it 100 nm or more, the influence of the interface between the temperature indicator 2 and the matrix material 3 on the detection temperature can be suppressed. Furthermore, by making it 1 mm or less, it becomes difficult to distinguish and visually recognize the temperature indicator 2 and the matrix material 3, and color unevenness of the temperature detection material can be suppressed. The size of the phase consisting of the temperature indicator 2 can be reduced by adding a surfactant or by cooling while stirring in the cooling process. The major axis of the phase consisting of the temperature indicator 2 is the major axis of an ellipse when the phase consisting of the temperature indicator 2 is approximated to an ellipse.
　上記の条件を満たす温度検知材料中への示温材２の分散の手法として、示温材２をマイクロカプセル化して、マイクロカプセルを分散媒に分散させる手法もある。マイクロカプセル膜を分散媒と考え、マイクロカプセル化した示温材２をそのまま用いることも可能である。 As a method for dispersing the temperature-indicating material 2 in a temperature-detecting material that satisfies the above conditions, there is a method in which the temperature-indicating material 2 is microencapsulated and the microcapsules are dispersed in a dispersion medium. It is also possible to use the microencapsulated temperature-indicating material 2 as it is, considering the microcapsule membrane as the dispersion medium.
　温度検知材料中には、結晶化により色が変わる性能が保持されれば、ロイコ染料、顕色剤、消色剤以外の材料を含むこともできる。たとえば、相分離構造体１中にマイクロカプセルなどを含むこともできる。これにより、２種以上の示温材２を温度検知材料に含むことが可能であり、２通り以上の温度変化を検知する材料を作製することが可能である。 The temperature sensing material can contain materials other than the leuco dye, developer, and decolorizer, so long as the ability to change color through crystallization is maintained. For example, microcapsules can be included in the phase separation structure 1. This makes it possible to include two or more types of temperature indicators 2 in the temperature sensing material, making it possible to create a material that can detect two or more types of temperature changes.
　示温材２をマイクロカプセル化することにより、示温材２の光や湿度等に対する耐環境性が向上し、保存安定性、変色特性の安定化等が可能となる。また、マイクロカプセル化により、インクを調製した際に、ロイコ染料、顕色剤、消色剤が他の樹脂剤、添加剤等の化合物から受ける影響を抑制することが可能である。 By microencapsulating the temperature-indicating material 2, the temperature-indicating material 2's environmental resistance to light, humidity, etc. is improved, and storage stability and discoloration characteristics can be stabilized. Microencapsulation also makes it possible to suppress the effects of other resins, additives, and other compounds on the leuco dye, developer, and decolorizing agent when preparing the ink.
　マイクロカプセル化には、公知の各種手法を適用することが可能である。例えば、乳化重合法、懸濁重合法、コアセルベーション法、界面重合法、スプレードライング法等を挙げることができるが、これらに限定されるものではない。また、２種以上異なる方法を組み合わせてもよい。 Various known methods can be used for microencapsulation. Examples include, but are not limited to, emulsion polymerization, suspension polymerization, coacervation, interfacial polymerization, and spray drying. Two or more different methods may be combined.
　マイクロカプセルに用いる樹脂被膜としては、多価アミンとカルボニル化合物から成る尿素樹脂被膜、メラミン・ホルマリンプレポリマ、メチロールメラミンプレポリマ、メチル化メラミンプレポリマーから成るメラミン樹脂被膜、多価イソシアネートとポリオール化合物から成るウレタン樹脂被膜、多塩基酸クロライドと多価アミンから成るアミド樹脂被膜、酢酸ビニル、スチレン、（メタ）アクリル酸エステル、アクリロニトリル、塩化ビニル等の各種モノマー類から成るビニル系の樹脂被膜が挙げられるが、これらに限定されるものではない。さらに、形成した樹脂被膜の表面処理を行い、インクや塗料化する際の表面エネルギーを調整することで、マイクロカプセルの分散安定性を向上させる等、追加の処理をすることもできる。 The resin coatings used for the microcapsules include, but are not limited to, urea resin coatings made of polyamines and carbonyl compounds, melamine-formaldehyde prepolymers, methylol melamine prepolymers, melamine resin coatings made of methylated melamine prepolymers, urethane resin coatings made of polyisocyanates and polyol compounds, amide resin coatings made of polybasic acid chlorides and polyamines, and vinyl resin coatings made of various monomers such as vinyl acetate, styrene, (meth)acrylic acid esters, acrylonitrile, and vinyl chloride. In addition, additional treatments can be performed, such as by surface treating the formed resin coating and adjusting the surface energy when making it into ink or paint, to improve the dispersion stability of the microcapsules.
　また、マイクロカプセルの直径は、保存安定性等が課題となるため、０．１～１００μｍ程度の範囲が好ましく、さらに好ましくは、０．１～１０μｍの範囲がよい。 In addition, since storage stability and other issues are an issue, the diameter of the microcapsules is preferably in the range of about 0.1 to 100 μm, and more preferably in the range of 0.1 to 10 μm.
　相分離構造体１は、乳鉢などで砕いて、粉体化することも可能である。これによりマイクロカプセルと同様の取り扱いが可能である。 The phase-separated structure 1 can also be crushed in a mortar or other container to produce a powder. This allows it to be handled in the same way as microcapsules.
　相分離構造体１およびマイクロカプセルは、溶媒や樹脂材料等と混合し、溶媒インク化することも可能である。その際、インク化のための分散安定化や、溶剤への耐性向上や、光や湿度等に対する耐環境性が向上などのため、シランカップリング処理、表面グラフト化、コロナ処理などにより表面処理をしても構わない。また、相分離構造体１およびマイクロカプセルを、さらにマトリックス材３やマイクロカプセルで被覆することも可能である。
＜相分離構造体の製造方法＞
　第１温度検知材料（相分離構造体１）は、例えば、以下の方法で作製することができる。温度検知材料の製造方法は、ロイコ染料と、顕色剤と、消色剤と、マトリックス材と、をマトリックス材の融点以上の温度に加温し、混合する混合工程と、混合工程で得られる混合物を、マトリックス材の凝固点以下の温度に冷却する冷却工程と、を備える。冷却工程において、マトリックス材と示温材とは速やかに相分離し、マトリックス材中にロイコ染料と、顕色剤と、消色剤とからなる相が分散した相分離構造を形成する。 The phase-separated structure 1 and the microcapsules can be mixed with a solvent, a resin material, or the like to form a solvent ink. In this case, surface treatment such as silane coupling treatment, surface grafting, corona treatment, or the like may be performed to stabilize the dispersion for forming the ink, improve resistance to the solvent, and improve environmental resistance to light, humidity, etc. The phase-separated structure 1 and the microcapsules can also be further covered with a matrix material 3 or microcapsules.
<Method of producing a phase-separated structure>
The first temperature detection material (phase-separated structure 1) can be produced, for example, by the following method. The method for producing the temperature detection material includes a mixing step of heating and mixing a leuco dye, a color developer, a decolorizer, and a matrix material to a temperature equal to or higher than the melting point of the matrix material, and a cooling step of cooling the mixture obtained in the mixing step to a temperature equal to or lower than the freezing point of the matrix material. In the cooling step, the matrix material and the temperature indicator quickly undergo phase separation to form a phase-separated structure in which phases consisting of the leuco dye, the color developer, and the decolorizer are dispersed in the matrix material.
　マトリックス材の融点以上に加温し液体状態にする際、示温材と、マトリックス材の相溶性次第で、示温材とマトリックス材が相溶する（示温材が微小に分散し、目視上相溶しているように見える）場合と、相溶しない（示温材とマトリックス材が２相に分離する）場合がある。このとき、相溶している方が取扱いやすさの観点において好ましい。示温材とマトリックス材は、マトリックス材が固体状態である使用温度のときは相分離する必要があるが、マトリックス材が液体状態である加温状態ではその限りではない。使用温度で示温材とマトリックス材とが相分離し、加温状態で示温材とマトリックス材とが相溶するためには、特に含有量の多い消色剤の極性がある程度の範囲内にあるとよい。消色剤の極性が小さすぎると使用温度でマトリックス材と相溶してしまい、極性が大きすぎると、加温状態でマトリックス材と分離してしまう。具体的な極性の計算方法としてハンセン溶解度パラメーターにより予測される分子間の双極子相互作用によるエネルギーδｐおよび分子間の水素結合によるエネルギーδｈがそれぞれ１以上１０以下である材料を好ましく用いることができる。しかしながら、消色剤の極性が大きく、加温状態でも示温材とマトリックス材が相溶しない材料についても、撹拌しながら冷却することで、相分離構造を形成させることは可能である。また、界面活性剤を添加して、相溶させてもよい。 When the matrix material is heated above its melting point to become liquid, it may be compatible with the matrix material (the temperature indicator is finely dispersed and appears to be compatible to the naked eye) or it may not be compatible (the temperature indicator and matrix material separate into two phases) depending on the compatibility between the two materials. In this case, compatibility is preferable from the viewpoint of ease of handling. The temperature indicator and the matrix material need to be phase-separated at the operating temperature when the matrix material is in a solid state, but this is not the case when the matrix material is in a liquid state under heating. In order for the temperature indicator and the matrix material to phase-separate at the operating temperature and to be compatible with each other under heating, it is preferable that the polarity of the decolorizing agent, which is particularly high in content, is within a certain range. If the polarity of the decolorizing agent is too small, it will be compatible with the matrix material at the operating temperature, and if the polarity is too large, it will separate from the matrix material under heating. As a specific method for calculating polarity, it is preferable to use a material in which the energy δp due to intermolecular dipole interactions and the energy δh due to intermolecular hydrogen bonds predicted by the Hansen solubility parameters are 1 to 10. However, even in materials in which the polarity of the decolorizing agent is high and the temperature indicator and matrix material are not compatible even when heated, it is possible to form a phase separation structure by cooling with stirring. A surfactant may also be added to make them compatible.
　マトリックス材の凝固点以下に冷却し、相分離構造を形成させる際、示温材とマトリックス材との相溶性次第で、示温材の分散構造の大きさが異なる。特に含有量の多い消色剤とマトリックス材について、ある程度相溶性がよいと細かく分散し、相溶性が悪いと大きく分散する。分散構造の大きさは特に限定されないが、１００ｎｍ未満になると、示温材とマトリックス材との界面の影響が出てくるため、検知温度に影響が出ることがある。また、１ｍｍを超えると、示温材とマトリックス材のそれぞれを視認することが可能になり、温度検知体の色ムラが大きくなる。そのため、分散構造の大きさは１００ｎｍ以上、１ｍｍ以下が好ましく、特に、１００ｎｍ以上、１００μｍ以下が最も好ましい。この分散構造を実現するためにも、具体的な極性の計算方法としてハンセン溶解度パラメーターにより予測される分子間の双極子相互作用によるエネルギーδｐおよび分子間の水素結合によるエネルギーδｈがそれぞれ１以上１０以下である消色剤を好ましく用いることができる。また、冷却工程において、撹拌しながら冷却することや界面活性剤を添加することで、分散構造の大きさを小さくすることも可能である。
＜加熱式マーキング装置＞
　第１温度検知材料は、様々な加熱式マーキング装置に適用することができる。加熱式マーキング装置は、加熱により材料を低粘度に制御し、材料を吐出、印刷する装置であり、加熱式インクジェットプリンタや加熱式ディスペンサやグルーガン等が挙げられる。相分離構造体からなる温度検知材料は、マトリックス材および示温材の融点以上に加熱することで低粘度な液体状態となるため、インク化することなく、加熱式マーキング装置にて印刷可能である。さらに、印刷時の加熱により色の初期化が可能であるため、印刷直後からの温度検知材料による温度管理が可能である。このことは、加熱式マーキング装置とは別に、温度検知材料を初期化するための加熱装置が不要になることを意味するため、設備コストの観点から有用である。加熱式マーキング装置により印刷するタイミングとしては、管理温度下にて温度管理した被印字対象物に温度検知材料を印刷したり、室温下などにて被印字対象物に温度検知材料を印刷した後、温度検知材料が顕色する前に管理温度帯に被印字対象物を移動させたりすること等が考えられる。
＜インク化＞
　予めマトリックス材料中に示温材が分散した相分離構造体や、マイクロカプセル化した第１温度検知材料を作製し、溶剤と混合することにより、温度検知インクを作製することが可能である。温度検知インクは、ペン、スタンプ、クレヨン、インクジェットなどのインクや印刷用の塗料に適用することが可能となる。 When the matrix material is cooled below its freezing point to form a phase separation structure, the size of the dispersion structure of the temperature indicator varies depending on the compatibility between the temperature indicator and the matrix material. In particular, for a decolorizing agent and a matrix material with a high content, if the compatibility is good to a certain extent, the temperature indicator is finely dispersed, and if the compatibility is poor, the temperature indicator is largely dispersed. The size of the dispersion structure is not particularly limited, but if it is less than 100 nm, the interface between the temperature indicator and the matrix material will be affected, which may affect the detection temperature. In addition, if it exceeds 1 mm, it becomes possible to visually recognize each of the temperature indicator and the matrix material, and the color unevenness of the temperature detector will increase. Therefore, the size of the dispersion structure is preferably 100 nm or more and 1 mm or less, and most preferably 100 nm or more and 100 μm or less. In order to realize this dispersion structure, a decolorizing agent in which the energy δp due to the dipole interaction between molecules and the energy δh due to the hydrogen bond between molecules, which are predicted by the Hansen solubility parameter as a specific polarity calculation method, are 1 to 10, can be preferably used. In the cooling step, it is also possible to reduce the size of the dispersed structure by cooling with stirring or by adding a surfactant.
<Heat-type marking device>
The first temperature detection material can be applied to various heating marking devices. The heating marking device is a device that controls the viscosity of a material to be low by heating, and ejects and prints the material, and examples of such devices include a heating inkjet printer, a heating dispenser, and a glue gun. The temperature detection material made of a phase separation structure becomes a low-viscosity liquid state by heating it to a temperature above the melting point of the matrix material and the temperature indicator, so it can be printed by a heating marking device without being turned into ink. Furthermore, since the color can be initialized by heating during printing, temperature control by the temperature detection material is possible immediately after printing. This means that a heating device for initializing the temperature detection material is not required separately from the heating marking device, and is therefore useful from the viewpoint of equipment costs. As for the timing of printing by the heating marking device, the temperature detection material can be printed on a print target object that has been temperature-controlled under a controlled temperature, or the temperature detection material can be printed on the print target object at room temperature or the like, and then the print target object is moved to a controlled temperature zone before the temperature detection material develops its color.
<Inkification>
It is possible to prepare a temperature sensing ink by preparing a phase separation structure in which a temperature indicator is dispersed in a matrix material or a microencapsulated first temperature sensing material in advance and mixing it with a solvent. The temperature sensing ink can be applied to inks for pens, stamps, crayons, inkjet printers, and the like, and to paints for printing.
　温度検知インクは、溶剤中に第１温度検知材料が分散した形態を示す。そのためには、示温材を包含するマトリックス材料やマイクロカプセルと相溶性が低い溶剤を用いる必要がある。 The temperature sensing ink has a form in which the first temperature sensing material is dispersed in a solvent. To achieve this, it is necessary to use a solvent that has low compatibility with the matrix material and microcapsules that contain the temperature-indicating material.
　マトリックス材料を用いた相分離構造体を温度検知材料として用いる場合、溶剤としては、極性の高い溶媒を用いることが好ましい。極性の高い溶媒としては、水、グリセリン、メタノール、エタノール、プロパノールなどのアルコール類を好ましく用いることができる。他にも、アセトン、メチルエチルケトン、シクロヘキサノンなどのケトン類、酢酸エチル、酢酸メチル、プロピオン酸エチル、プロピオン酸メチルなどのエステル類、ジメチルエーテル、テトラヒドロフランなどのエーテル類等を用いることができる。 When a phase-separated structure using a matrix material is used as a temperature sensing material, it is preferable to use a highly polar solvent as the solvent. As highly polar solvents, water, glycerin, and alcohols such as methanol, ethanol, and propanol can be preferably used. Other examples that can be used include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, esters such as ethyl acetate, methyl acetate, ethyl propionate, and methyl propionate, and ethers such as dimethyl ether and tetrahydrofuran.
　マイクロカプセル化した温度検知材料を用いる場合、溶剤としては、マイクロカプセルの材質が耐性をもつ溶媒を用いることが好ましい。マイクロカプセルの材質として極性の高い材質を用いた場合、極性の低い有機溶媒を用いたほうが良く、具体的には、ヘキサン、ベンゼン、トルエンなどの無極性溶媒、石油、鉱物油、シリコーンオイルなどの油類が特に好ましく、他には、アセトン、メチルエチルケトン、シクロヘキサノンなどのケトン類、酢酸エチル、酢酸メチル、プロピオン酸エチル、プロピオン酸メチルなどのエステル類、ジメチルエーテル、テトラヒドロフランなどのエーテル類等があげられる。 When using a microencapsulated temperature sensing material, it is preferable to use a solvent that the microcapsule material is resistant to. When using a highly polar material for the microcapsule material, it is better to use an organic solvent with low polarity. Specifically, non-polar solvents such as hexane, benzene, toluene, and oils such as petroleum, mineral oil, and silicone oil are particularly preferable. Other examples include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, esters such as ethyl acetate, methyl acetate, ethyl propionate, and methyl propionate, and ethers such as dimethyl ether and tetrahydrofuran.
　マイクロカプセルの材質として極性の低い材質を用いた場合、極性の高い溶媒を用いたほうが良く、具体的には、水、グリセリン、メタノール、エタノール、プロパノールなどのアルコール類を好ましく用いることができる。他にも、アセトン、メチルエチルケトン、シクロヘキサノンなどのケトン類、酢酸エチル、酢酸メチル、プロピオン酸エチル、プロピオン酸メチルなどのエステル類、ジメチルエーテル、テトラヒドロフランなどのエーテル類等を用いることができる。 When a material with low polarity is used as the material for the microcapsules, it is better to use a solvent with high polarity. Specifically, water, glycerin, and alcohols such as methanol, ethanol, and propanol can be preferably used. Other examples that can be used include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, esters such as ethyl acetate, methyl acetate, ethyl propionate, and methyl propionate, and ethers such as dimethyl ether and tetrahydrofuran.
　これらの温度検知インクは液体状態においても温度及び時間検知機能を有し、さらに被印字対象等に印字、筆記、押印等することにより溶媒が揮発することで、温度検知材料のみが印字物を構成する。この印字物を、温度インジケータとして使用することができる。 These temperature sensing inks have temperature and time sensing capabilities even in a liquid state, and when they are printed, written, stamped, etc. on a target object, the solvent evaporates, leaving only the temperature sensing material to form the printed matter. This printed matter can be used as a temperature indicator.
　温度検知インクには、温度及び時間検知機能に影響しない程度であれば、有機溶媒や水などの溶液に添加物をさらに添加してもよい。例えば、顔料を含むことで、消色時、顕色時の色を変更することが可能である。 Additives may be added to the temperature sensing ink in the form of a solution such as organic solvent or water, as long as they do not affect the temperature and time detection functions. For example, by including a pigment, it is possible to change the color when the ink is erased or developed.
　温度検知インクは、各種添加剤や溶媒が使用可能である。また温度検知材料や添加剤の量を変えることで、粘度を調整することも可能である。これにより、オフセット印刷、グラビア印刷、フレキソ印刷、ラベルプリンタ、サーマルプリンタなどの様々な印刷装置用インクとして適用可能である。
＜インクジェット用インク＞
　インク溶液の抵抗が高い場合、帯電制御式インクジェットプリンタにおけるインクの吐出部において、インク粒子がまっすぐ飛ばず、曲がる傾向がある。そのため、インク溶液の抵抗は概ね２０００Ωｃｍ以下にする必要がある。 Various additives and solvents can be used for the temperature sensing ink. It is also possible to adjust the viscosity by changing the amount of the temperature sensing material or additives. This makes it applicable as an ink for various printing devices such as offset printing, gravure printing, flexographic printing, label printers, and thermal printers.
<Inkjet ink>
When the resistance of an ink solution is high, the ink droplets tend to bend rather than fly straight at the ink ejection section of a charge-controlled inkjet printer, so the resistance of the ink solution needs to be approximately 2000 Ωcm or less.
　インクに含まれる樹脂、有機溶媒（特に、インクジェットプリンタ用インクの有機溶媒としてよく用いられるメチルエチルケトン、エタノール等）は導電性が低いので、インク溶液の抵抗は５０００～数万Ωｃｍ程度と大きい。抵抗が高いと、帯電制御式インクジェットプリンタでは所望の印字が困難となる。そこで、インク溶液の抵抗を下げるために、インクに導電剤を添加する必要がある。 The resins and organic solvents contained in the ink (particularly methyl ethyl ketone, ethanol, etc., which are often used as organic solvents in inkjet printer inks) have low conductivity, so the resistance of the ink solution is high, at around 5,000 to tens of thousands of Ω cm. If the resistance is high, it becomes difficult to print as desired with a charge-controlled inkjet printer. Therefore, in order to lower the resistance of the ink solution, it is necessary to add a conductive agent to the ink.
　導電剤としては、錯体を用いることが好ましい。導電剤は用いる溶剤に溶解することが必要で、色調に影響を与えないことも重要である。また導電剤は一般には塩構造のものが用いられる。これは分子内に電荷の偏りを有するので、高い導電性が発揮できるものと推定される。 It is preferable to use a complex as the conductive agent. The conductive agent must be soluble in the solvent used, and it is also important that it does not affect the color tone. Furthermore, conductive agents with a salt structure are generally used. This is thought to be because the charge is biased within the molecule, allowing it to exhibit high conductivity.
　以上のような観点で検討した結果、導電剤は塩構造で、陽イオンはテトラアルキルアンモニウムイオン構造が好適である。アルキル鎖は直鎖、分岐どちらでもよく、炭素数が大きいほど溶媒に対する溶解性は向上する。しかし炭素数が小さいほど、僅かの添加率で抵抗を下げることが可能となる。インクに使う際の現実的な炭素数は２～８程度である。 After considering the above points, it was found that the conductive agent should have a salt structure and the cation should have a tetraalkylammonium ion structure. The alkyl chain can be either straight or branched, and the larger the carbon number, the better the solubility in the solvent. However, the smaller the carbon number, the more it is possible to reduce resistance with a small addition rate. A practical number of carbons for use in ink is around 2 to 8.
　陰イオンはヘキサフルオロフォスフェートイオン、テトラフルオロボレートイオン等が溶剤に対する溶解性が高い点で好ましい。 Hexafluorophosphate ions, tetrafluoroborate ions, etc. are preferred anions because they have high solubility in solvents.
　なお、過塩素酸イオンも溶解性は高いが、爆発性があるので、インクに用いるのは現実的ではない。それ以外に、塩素、臭素、ヨウ素イオンも挙げられるが、これらは鉄やステンレス等の金属に接触するとそれらを腐食させる傾向があるので好ましくない。 Although perchlorate ions are also highly soluble, they are explosive, so it is not practical to use them in ink. Other examples include chlorine, bromine, and iodine ions, but these are undesirable as they tend to corrode metals such as iron and stainless steel when they come into contact with them.
　以上より、好ましい導電剤は、テトラエチルアンモニウムヘキサフルオロフォスフェート、テトラプロピルアンモニウムヘキサフルオロフォスフェート、テトラブチルアンモニウムヘキサフルオロフォスフェート、テトラペンチルアンモニウムヘキサフルオロフォスフェート、テトラヘキシルアンモニウムヘキサフルオロフォスフェート、テトラオクチルアンモニウムヘキサフルオロフォスフェート、テトラエチルアンモニウムテトラフルオロボレート、テトラプロピルアンモニウムテトラフルオロボレート、テトラブチルアンモニウムテトラフルオロボレート、テトラペンチルアンモニウムテトラフルオロボレート、テトラヘキシルアンモニウムテトラフルオロボレート、テトラオクチルアンモニウムテトラフルオロボレート等が挙げられる。
＜第２温度検知材料＞
　本実施形態に係る温度インジケータに含まれる第１温度検知材料は、図２Ｂに示した通り、Ｔ１近傍より高い温度域において、変色速度が低下することが課題である。これに対し、本実施形態に係る温度インジケータは、第１温度検知材料に加えて、更に第２温度検知材料を含むことで、Ｔ１近傍より高い温度域に到達したことを第２温度検知材料の変色にて示すことが可能である。 In view of the above, preferred conductive agents include tetraethylammonium hexafluorophosphate, tetrapropylammonium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, tetrapentylammonium hexafluorophosphate, tetrahexylammonium hexafluorophosphate, tetraoctylammonium hexafluorophosphate, tetraethylammonium tetrafluoroborate, tetrapropylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, tetrapentylammonium tetrafluoroborate, tetrahexylammonium tetrafluoroborate, and tetraoctylammonium tetrafluoroborate.
<Second Temperature Sensing Material>
The first temperature detection material included in the temperature indicator according to this embodiment has an issue in that the color change rate decreases in a temperature range higher than the vicinity of T1, as shown in Fig. 2B. In response to this, the temperature indicator according to this embodiment further includes a second temperature detection material in addition to the first temperature detection material, and is therefore able to indicate that a temperature range higher than the vicinity of T1 has been reached by a color change of the second temperature detection material.
　図６Ａは、第２温度検知材料の変色速度の温度依存性を示す図である。食品や医薬品の品質劣化を模擬するにあたり、第１温度検知材料の変色速度が遅くなってしまう温度域において、変色速度が速い第２温度検知材料を用いることで、機能補完することが目的になる。そのため、ある温度（変色開始温度をＴ２とする）で急峻に変色開始する材料が好ましく、変色速度についても、ある温度以上で急激に変色速度が大きくなる材料が好ましい。なお、Ｔ２は、「色変化開始温度」とも称呼される場合がある。 FIG. 6A shows the temperature dependence of the discoloration rate of the second temperature detection material. In simulating the quality deterioration of food or medicine, the purpose is to complement the function by using a second temperature detection material with a fast discoloration rate in a temperature range where the discoloration rate of the first temperature detection material becomes slow. For this reason, a material that starts to discolor abruptly at a certain temperature (discoloration onset temperature is T2) is preferable, and a material whose discoloration rate increases rapidly above a certain temperature is also preferable. Note that T2 is sometimes referred to as the "color change onset temperature."
　図６Ｂは、第１温度検知材料と第２温度検知材料の変色速度の温度依存性を示す図である。第１温度検知材料は、食品や医薬品の管理温度を逸脱した際、管理温度近傍では緩やかに変色する材料が求められるが、第２温度検知材料には、食品や医薬品が非常に高温に晒された際、異常加熱が発生したことを検知するために、高温にて非常に早く変色する材料が求められる。そのため、第２温度検知材料の変色速度としては、第１温度検知材料の変色速度よりも速くなる方が良い。 Figure 6B is a diagram showing the temperature dependence of the discoloration speed of the first and second temperature detection materials. The first temperature detection material is required to be a material that changes color slowly near the controlled temperature when the controlled temperature of food or medicine is exceeded, but the second temperature detection material is required to be a material that changes color very quickly at high temperatures in order to detect abnormal heating when food or medicine is exposed to very high temperatures. Therefore, it is better for the discoloration speed of the second temperature detection material to be faster than that of the first temperature detection material.
　第２温度検知材料は、第１温度検知材料（示温材）のガラス転移点Ｔｇよりも高く、且つ、第１温度検知材料（示温材）の融点Ｔｍよりも低い温度範囲内で不可逆的に色変化する。また、第２温度検知材料の変色開始温度Ｔ２（色変化開始温度）は、第１温度検知材料の変色速度の極大値Ｔ１の近傍にあることが好ましい。これにより、第１温度検知材料の変色速度が遅くなってしまう温度域において、すみやかに第２温度検知材料の変色が発生するため、温度インジケータの変色により、温度異常状態を示すことが可能である。第２温度検知材料の変色開始温度Ｔ２が、第１温度検知材料の顕色開始温度Ｔaや示温材のガラス転移点Ｔｇより低いと、第１温度検知材料の変色速度が温度上昇に対して増加するという機能が発現するより低い温度で第２温度検知材料の変色が発生してしまい、TTIとしての機能が失われることになる。また、第２温度検知材料の変色開始温度をＴ２が、第１温度検知材料の消色開始温度Ｔｄや示温材の融点Ｔｍより高いと、食品や医薬品が非常に高温に晒された際、第１温度検知材料と第２温度検知材料のいずれも発色しない温度域ができてしまい、第２温度検知材料を含む意味合いが薄くなってしまう。なお、第１温度検知材料の変色速度の極大値Ｔ１は、「色変化速度最大温度」とも称呼される場合がある。 The second temperature detection material irreversibly changes color within a temperature range that is higher than the glass transition point Tg of the first temperature detection material (temperature indicator) and lower than the melting point Tm of the first temperature detection material (temperature indicator). In addition, it is preferable that the discoloration start temperature T2 (color change start temperature) of the second temperature detection material is close to the maximum value T1 of the discoloration speed of the first temperature detection material. This allows the second temperature detection material to discolor quickly in a temperature range where the discoloration speed of the first temperature detection material slows down, making it possible to indicate an abnormal temperature state by the discoloration of the temperature indicator. If the discoloration start temperature T2 of the second temperature detection material is lower than the color development start temperature Ta of the first temperature detection material or the glass transition point Tg of the temperature indicator, the second temperature detection material will discolor at a lower temperature than the temperature at which the function of the discoloration speed of the first temperature detection material increasing with increasing temperature is expressed, and the function as a TTI will be lost. Furthermore, if the discoloration start temperature T2 of the second temperature detection material is higher than the discoloration start temperature Td of the first temperature detection material or the melting point Tm of the thermochromic material, when the food or medicine is exposed to very high temperatures, a temperature range will be created where neither the first nor the second temperature detection material will develop color, making the inclusion of the second temperature detection material less meaningful. Note that the maximum discoloration rate T1 of the first temperature detection material is sometimes referred to as the "maximum color change rate temperature."
　第１温度検知材料の結晶化速度は、図２Ｂのようなグラフになるが、示温材の種類によっては、結晶が準安定相（配向が乱れた結晶）を形成する温度域と、安定相を形成する温度域を有するものがある。このことなどにより、結晶化速度は図２Ｂのような単一のピークではなく、複数のピークに分かれる場合や見かけ上ブロード（最大値からの変化率が緩やか）なピークになる場合がある。特に結晶化速度の最大値を取る温度Ｔ1以上の温度にて、緩やかに速度が低下するピークになることが多い。変色速度も同様である。そのため、第２温度検知材料の変色開始温度Ｔ２は、第１温度検知材料の変色速度の極大値Ｔ１の近傍にて、第１温度検知材料の種類に応じて、適宜最適な温度に調整することが良い。 The crystallization rate of the first temperature detection material is shown in a graph as in Figure 2B, but some types of temperature indicators have a temperature range where the crystals form a metastable phase (crystals with disordered orientation) and a temperature range where they form a stable phase. For this reason, the crystallization rate may not be a single peak as in Figure 2B, but may be divided into multiple peaks or may appear to be a broad peak (with a gradual rate of change from the maximum value). In particular, at temperatures above the temperature T1 at which the crystallization rate reaches its maximum value, the rate often peaks and gradually decreases. The same is true for the discoloration rate. For this reason, it is advisable to adjust the discoloration start temperature T2 of the second temperature detection material to an appropriate optimum temperature in the vicinity of the maximum value T1 of the discoloration rate of the first temperature detection material, depending on the type of first temperature detection material.
　第１温度検知材料の具体的な変色温度に関し、食品や医薬品の品質管理に適用することを想定すると、変色開始温度に関係するガラス転移点Ｔｇは－４０℃以上６０℃以下であり、且つ、初期化温度に関係する融点Ｔｍは６０℃以上１５０℃以下であり、且つ、ＴｇとＴｍとの温度差は、１００℃以上１５０℃以下であることが好ましい。このような温度関係であれば、変色速度の極大値Ｔ１の－２０℃以上６０℃以下の範囲に第２温度検知材料の変色開始温度Ｔ２を調整することが好ましい。 As regards the specific discoloration temperature of the first temperature detection material, assuming application to the quality control of food and pharmaceuticals, it is preferable that the glass transition point Tg related to the discoloration onset temperature is -40°C or higher and 60°C or lower, the melting point Tm related to the initialization temperature is 60°C or higher and 150°C or lower, and the temperature difference between Tg and Tm is 100°C or higher and 150°C or lower. With such a temperature relationship, it is preferable to adjust the discoloration onset temperature T2 of the second temperature detection material to the range of -20°C or higher and 60°C or lower of the maximum value T1 of the discoloration rate.
　図７Ａは、第２温度検知材料の色濃度と温度との関係を示す図である。第２温度検知材料は、昇温過程で、変色開始温度Ｔ２以上に温度を上げると変色する。この際、再び温度が降下したとしても、色戻りしないことが要求される。色が元に戻ってしまうと、温度の変化の有無を把握することができないためである。すなわち、一度変色したら色戻りしない不可逆性の示温材を好ましく用いることができる。 FIG. 7A shows the relationship between the color density and temperature of the second temperature detection material. The second temperature detection material changes color when the temperature is raised above the discoloration starting temperature T2 during the heating process. At this time, it is required that the color does not return to its original state even if the temperature drops again. If the color returns to its original state, it will be impossible to determine whether the temperature has changed or not. In other words, it is preferable to use an irreversible temperature indicator that does not return to its original color once it has changed color.
　図７Ｂは、第１温度検知材料及び第２温度検知材料の色濃度と温度の関係を示す図である。第２温度検知材料の変色開始温度Ｔ２は、第１温度検知材料の顕色開始温度Ｔaよりも高く、消色開始温度Ｔｄよりも低いことが特徴である。 FIG. 7B shows the relationship between the color density and temperature of the first and second temperature detection materials. The second temperature detection material's discoloration start temperature T2 is higher than the color development start temperature Ta of the first temperature detection material and lower than the decolorization start temperature Td.
　また、第１温度検知材料は消色温度Ｔｄ以上に加熱することで色を初期化できるという特徴があるが、第２温度検知材料にはこの機能を求めていない。第１温度検知材料の変色開始温度は食品や医薬品の管理温度近傍、すなわち冷凍・冷蔵などの低温域であることが多く、初期化機能が無いと温度検知材料の保管・運用自体が難しくなる。それに対し、第２温度検知材料は、異常加熱されたことを検知することを目的としており、初期化機能がなくても、常温での保管・運用が可能であることが多いためである。勿論、初期化機能を有する材料を用いることも可能であるが、ある温度にて急峻に変色する不可逆性の示温材は、汎用的な材料が多数存在するため、それらを用いることで、温度インジケータの低コスト化を図ることが可能である。 The first temperature detection material has the characteristic that its color can be initialized by heating it above the decolorization temperature Td, but this function is not required for the second temperature detection material. The first temperature detection material often begins to discolor at temperatures close to the management temperatures for food and medicine, i.e., in the low temperature range such as freezing and refrigeration, and without the initialization function, the temperature detection material itself becomes difficult to store and use. In contrast, the second temperature detection material is intended to detect abnormal heating, and it can often be stored and used at room temperature even without the initialization function. Of course, it is possible to use a material with an initialization function, but there are many general-purpose materials that are irreversible temperature indicators that change color sharply at a certain temperature, so by using them, it is possible to reduce the cost of the temperature indicator.
　第２温度検知材料としては、第１温度検知材料の変色速度の極大値Ｔ１近傍の温度にて急峻に変色する不可逆性の示温材を幅広く用いることが可能である。例えば、感熱材、感熱紙、感熱シート、感熱塗料、感熱インク、感熱マイクロカプセルなど、汎用的な示温材を温度インジケータの構造に合せて選択することが可能である。
＜温度インジケータの構成＞
　本実施形態に係る温度インジケータは、第１温度検知材料および第２温度検知材料に加えて、これらを直接的又は間接的に支持する基材を含んでいてもよい。本実施形態に係る温度インジケータは、基材と、前記第１温度検知材料および前記第２温度検知材料とを少なくとも含んでいれば、様々な構成を用いることができる。第１温度検知材料と第２温度検知材料とが接触していても良いし、基材内にて離れていても良い。またインクの中に第１温度検知材料のマイクロカプセルと第２温度検知材料のマイクロカプセルを含むことなどにより、見かけ上１種の温度検知材料として取り扱うことも可能である。 As the second temperature detection material, a wide variety of irreversible temperature indicators that undergo a steep color change at a temperature near the maximum value T1 of the color change rate of the first temperature detection material can be used. For example, general-purpose temperature indicators such as heat-sensitive materials, heat-sensitive paper, heat-sensitive sheets, heat-sensitive paints, heat-sensitive inks, and heat-sensitive microcapsules can be selected according to the structure of the temperature indicator.
<Temperature indicator configuration>
The temperature indicator according to the present embodiment may include a substrate that directly or indirectly supports the first and second temperature sensing materials in addition to the first and second temperature sensing materials. The temperature indicator according to the present embodiment may have various configurations as long as it includes at least the substrate and the first and second temperature sensing materials. The first and second temperature sensing materials may be in contact with each other or may be separated from each other within the substrate. It is also possible to treat the ink as a single type of temperature sensing material by including microcapsules of the first and second temperature sensing materials in the ink.
　温度インジケータは以下の形態に限定されるものではないが、一例を示す。 The temperature indicator is not limited to the following form, but is an example.
　図８は、最も簡易的な温度インジケータの例を示す模式図である。温度インジケータ４は、基材５と第１温度検知材料１と第２温度検知材料６とを有し、第１温度検知材料１と第２温度検知材料６をそれぞれ基材５の一主面上に配置している。なお、第１温度検知材料が基材５の一主面に配置され、第２温度検知材料６が基材５の他主面に配置されてもよい。 FIG. 8 is a schematic diagram showing an example of the simplest temperature indicator. The temperature indicator 4 has a substrate 5, a first temperature detection material 1, and a second temperature detection material 6, and the first temperature detection material 1 and the second temperature detection material 6 are each disposed on one main surface of the substrate 5. Note that the first temperature detection material may be disposed on one main surface of the substrate 5, and the second temperature detection material 6 may be disposed on the other main surface of the substrate 5.
　温度検知材料が基材から剥離しないように、第１温度検知材料１と第２温度検知材料６の一方、あるいは双方を透明基材や透明性のある接着剤などで覆っても良い。この温度インジケータにおいて、第１温度検知材料１の色が変色していれば、食品や医薬品が管理温度から逸脱し、品質劣化が進行していることを検知することができる。第２温度検知材料６の色が変色していれば、食品や医薬品が管理温度よりも顕著に高い温度に晒されたことを検知することができる。 One or both of the first temperature detection material 1 and the second temperature detection material 6 may be covered with a transparent substrate or a transparent adhesive to prevent the temperature detection material from peeling off from the substrate. In this temperature indicator, if the color of the first temperature detection material 1 changes, it can be detected that the food or medicine has deviated from the controlled temperature and is beginning to deteriorate. If the color of the second temperature detection material 6 changes, it can be detected that the food or medicine has been exposed to a temperature significantly higher than the controlled temperature.
　図８の温度インジケータ４では、第１温度検知材料１は加熱により初期化可能である。そのため、第１温度検知材料１のみを選択的に加熱することで、温度インジケータ４の初期化が可能である。第２温度検知材料６に初期化できない材料を用いる場合、第１温度検知材料１と第２温度検知材料６とを近い位置（近接するように）に配置すると、第１温度検知材料１を選択的に初期化することは難しくなる。一方で、第３者に簡単に初期化されてしまうことを防ぐ（第３者が初期化してしまったことを検知する）ことができる。この場合も、レーザー加熱などの微細加温など、第３者が取り扱うことが難しい加熱方法を用いることで、温度インジケータの初期化は可能である。 In the temperature indicator 4 in Figure 8, the first temperature detection material 1 can be initialized by heating. Therefore, the temperature indicator 4 can be initialized by selectively heating only the first temperature detection material 1. If a material that cannot be initialized is used for the second temperature detection material 6, it becomes difficult to selectively initialize the first temperature detection material 1 if the first temperature detection material 1 and the second temperature detection material 6 are placed in close positions (so that they are close to each other). On the other hand, it is possible to prevent a third party from easily initializing it (to detect initialization by a third party). In this case, too, it is possible to initialize the temperature indicator by using a heating method that is difficult for a third party to handle, such as fine heating using laser heating.
　なお、近接とは、両者が接触している状態を含み、一方と他方との間の間隔がゼロ（即ち、接触状態）又は両者の間に間隔が有る場合、その両者の距離が近いことをいう。例えば、上記の微細加熱以外の加熱方法では両者のうちの一方のみの選択的な加熱が難しいような距離は、両者の距離が近いということができる。例えば、両者の距離が、４０ｍｍ以下である場合、両者の距離が近いということができる。
（基材）
　本実施形態において、基材の材料は、温度インジケータに要求される機能によって自由に選択できる。温度検知材料の初期化温度としては、６０℃以上１５０℃以下が最も好ましいため、温度インジケータを初期化することを想定する場合、この温度より耐熱性が高い基材であれば材質に依らず適用可能である。たとえば、紙やプラスチックなどの有機材料や、セラミックスや金属などの無機材料や、それらの複合材料など自由に選択可能である。高強度、耐熱性、耐候性、耐薬品性、断熱性、導電性など、温度インジケータに要求される特性に合わせて選択する。シールを用いることで、検知したい対象物に対して密着させる（ラベル化する）ことも可能である。また、透明性の有無も特に限定されない。温度検知材料が基材に接していない面から変化過程を観察可能である。透明基材や透明性のある接着剤などで温度検知材料を覆っている場合も同様に、変化過程を観察可能である。一方で、接着剤に透明性が無い場合でも、基材に透明性があれば、基材の外側から温度検知材料の変色過程を観察可能である。 Note that "close" includes a state in which the two are in contact with each other, and means that the distance between the two is close when there is zero space between them (i.e., a contact state) or when there is a space between them. For example, the distance between the two can be said to be close when it is difficult to selectively heat only one of the two using a heating method other than the above-mentioned fine heating. For example, the distance between the two can be said to be close when it is 40 mm or less.
(Base material)
In this embodiment, the material of the substrate can be freely selected depending on the function required for the temperature indicator. Since the initialization temperature of the temperature detection material is most preferably 60°C or more and 150°C or less, when it is assumed that the temperature indicator is initialized, any substrate that has a higher heat resistance than this temperature can be applied regardless of the material. For example, organic materials such as paper and plastic, inorganic materials such as ceramics and metals, and composite materials thereof can be freely selected. The material is selected according to the characteristics required for the temperature indicator, such as high strength, heat resistance, weather resistance, chemical resistance, heat insulation, and conductivity. By using a seal, it is also possible to adhere (label) the object to be detected. In addition, there is no particular limitation on the presence or absence of transparency. The change process can be observed from the surface where the temperature detection material is not in contact with the substrate. The change process can also be observed in the same way when the temperature detection material is covered with a transparent substrate or a transparent adhesive. On the other hand, even if the adhesive is not transparent, if the substrate is transparent, the discoloration process of the temperature detection material can be observed from the outside of the substrate.
　基材のデザイン等も限定されない。温度検知材料の変色特性以外の情報を印刷することや、温度検知材料の色を検査するために有効になる色を印刷することなどが可能である。 There are no limitations on the design of the substrate. It is possible to print information other than the color-changing characteristics of the temperature-sensing material, or to print a color that is useful for inspecting the color of the temperature-sensing material.
　基材は、数種の材料で層構造を形成してもよい。たとえば、図９のように、温度検知材料１の周りを囲うように基材５を形成させてもよい。これにより、温度検知材料１の基材５に対する平滑性が高くなるため、第１温度検知材料１の色濃度の濃淡が少なくなる。 The substrate may be a layered structure made of several materials. For example, as shown in FIG. 9, the substrate 5 may be formed to surround the temperature detection material 1. This increases the smoothness of the temperature detection material 1 relative to the substrate 5, reducing the variation in color density of the first temperature detection material 1.
　図９の一例では、第１温度検知材料１の上部を透明基材で覆っている。この透明基材および透明性のある接着剤７に、紫外線遮断材料などを含ませることで、温度検知材料１の光退色を抑制することなども可能である。また、紫外線、湿度、酸素などを検知して透明性が損なわれる材料を設けるなど、温度検知材料の変色特性以外の機能を温度インジケータに持たせることも可能である。 In the example shown in FIG. 9, the top of the first temperature detection material 1 is covered with a transparent base material. By incorporating an ultraviolet blocking material or the like into this transparent base material and the transparent adhesive 7, it is possible to suppress the photofading of the temperature detection material 1. It is also possible to give the temperature indicator functions other than the discoloration property of the temperature detection material, such as providing a material that loses its transparency upon detecting ultraviolet rays, humidity, oxygen, etc.
　図９の一例では、最上部に第２温度検知材料６を配置している。この構造では、第１温度検知材料の色を視認可能な面を第２温度検知材料が覆っているため、第２温度検知材料は初期状態において透明性を有する必要がある。この場合、例えば、透明感熱シールなどを好ましく用いることができる。図１０の一例のように、第２温度検知材料の配置位置をずらし、第１温度検知材料の色が視認可能であれば、第２温度検知材は透明性のない感熱シールでも問題ない。 In the example shown in Figure 9, the second temperature detection material 6 is placed at the top. In this structure, the second temperature detection material covers the surface where the color of the first temperature detection material is visible, so the second temperature detection material needs to be transparent in its initial state. In this case, for example, a transparent heat-sensitive sticker can be preferably used. As in the example shown in Figure 10, if the position of the second temperature detection material is shifted and the color of the first temperature detection material is visible, there is no problem with the second temperature detection material being a non-transparent heat-sensitive sticker.
　図９の一例などでは、たとえば、温度インジケータに第１温度検知材料と第２温度検知材料をそれぞれ付与するタイミングを変えることで、実運用しやすくすることが可能である。第２温度検知材料を付与する前の温度インジケータであれば、初期化が可能であるため、温度インジケータを食品や医薬品に付与する直前に加熱初期化し、その後に第２温度検知材料を付与することで、それ以降は第３者が初期化できない温度インジケータとし取り扱うことが可能である。 In the example shown in Figure 9, for example, by changing the timing at which the first temperature detection material and the second temperature detection material are applied to the temperature indicator, it is possible to make it easier to use in practice. Since the temperature indicator can be initialized before the second temperature detection material is applied, the temperature indicator can be initialized by heating just before being applied to food or medicine, and then the second temperature detection material can be applied, so that it can be treated as a temperature indicator that cannot be initialized by third parties thereafter.
　次に、実施例および比較例を示しながら本発明を更に具体的に説明する。なお、本発明はこれらの実施例に限定されるものではない。 Next, the present invention will be explained in more detail with reference to examples and comparative examples. Note that the present invention is not limited to these examples.
（第１温度検知材料の作製）
　ロイコ染料として３，３－ビス（ｐ－ジメチルアミノフェニル）－６－ジメチルアミノフタリド（山田化学工業製ＣＶＬ）を１重量部、顕色剤として東京化成工業製没食子酸オクチルを１重量部、消色剤として東京化成工業製ビタミンＫ４を１００重量部、マトリックス材料として三井化学製ハイワックス２００Ｐを１００重量部用いた。これらの材料を、消色剤およびマトリックス材の融点以上である１５０℃で溶かして混合し、自然冷却により固化させることで、相分離構造を有する温度検知材料を作製した。
（第１温度検知材料の付与）
　作製した第１温度検知材料について、武蔵エンジニアリング製ジェットディスペンサＡｅｒｏＪｅｔにて１５０℃で加熱し、液体状態にすることで、基材上に吐出した。基材としては、汎用のコート紙を用いた。
（第２温度検知材料の付与、および温度インジケータの作製）
　第２温度検知材料として、東芝テック製クリアサーマルラベルを用いた。基材上に吐出した第１温度検知材料の近接位置に第２温度検知材料を貼付けることで、温度インジケータを作製した。
（変色特性の評価）
　温度インジケータ作製後、１分以内に物品の管理温度として想定し、示温材のガラス転移点（５℃程度）以下である０℃に５分保持した後、３０℃/分で示温材のガラス転移点以上の２５℃まで昇温し、その状態での温度インジケータの色濃度の時間変化を観察した。その結果を、図１１Ａ及び図１１Ｂ並びに図１２に示す。なお、図１１Ａは出願図面の仕様上、白黒画像になっており、カラー画像にした場合、黒はその濃度に応じた濃さの青色になる（図１３Ａ及び図１５Ａも同様。）。図１１Ｂは出願図面の仕様上、白黒画像になっており、カラー画像にした場合、黒はその濃度に応じた濃さの灰褐色になる（図１３Ｂ及び図１５Ｂも同様。）。 (Preparation of first temperature detection material)
The following materials were used: 1 part by weight of 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (CVL manufactured by Yamada Chemical Industry Co., Ltd.) as the leuco dye, 1 part by weight of octyl gallate manufactured by Tokyo Chemical Industry Co., Ltd. as the color developer, 100 parts by weight of Vitamin K4 manufactured by Tokyo Chemical Industry Co., Ltd. as the decolorizer, and 100 parts by weight of Hi-Wax 200P manufactured by Mitsui Chemicals Co., Ltd. as the matrix material. These materials were melted and mixed at 150°C, which is higher than the melting points of the decolorizer and matrix material, and then allowed to solidify by natural cooling, to produce a temperature detection material having a phase separation structure.
(Application of First Temperature Detection Material)
The prepared first temperature detection material was heated to 150° C. using a jet dispenser AeroJet manufactured by Musashi Engineering Co., Ltd., turned into a liquid state, and then discharged onto a substrate. General-purpose coated paper was used as the substrate.
(Application of second temperature sensing material and preparation of temperature indicator)
As the second temperature detection material, a clear thermal label manufactured by Toshiba Tec was used. A temperature indicator was produced by attaching the second temperature detection material to a position adjacent to the first temperature detection material discharged onto the substrate.
(Evaluation of discoloration properties)
After the temperature indicator was made, it was held at 0°C, which is below the glass transition point of the temperature indicator (about 5°C), for 5 minutes, assuming that the temperature indicator was the controlled temperature of the article, and then heated at 30°C/min to 25°C, which is above the glass transition point of the temperature indicator, and the change in color density of the temperature indicator over time was observed. The results are shown in Figures 11A, 11B, and 12. Note that Figure 11A is a black and white image due to the specifications of the application drawings, and if it were a color image, the black would be blue with a depth corresponding to the density (similar to Figures 13A and 15A). Figure 11B is a black and white image due to the specifications of the application drawings, and if it were a color image, the black would be gray-brown with a depth corresponding to the density (similar to Figures 13B and 15B).
　図１１Ａ及び図１１Ｂの画像、および図１２の色濃度データより、２５℃の温度下において、図１１Ａの第１温度検知材料が時間とともに顕色（青色に顕色）していく様子が確認された。これは２５℃という温度が、消色剤のガラス転移点以上であり、示温材が結晶化したためである。一方で、図１１Ｂの第２温度検知材料は全く変色しなかった。これにより、第１温度検知材料が、管理温度以上の温度にて温度と時間の積算にて変色する過程が確認できた。 From the images in Figures 11A and 11B, and the color density data in Figure 12, it was confirmed that at a temperature of 25°C, the first temperature detection material in Figure 11A developed color (turned blue) over time. This is because 25°C is above the glass transition point of the decolorizer, causing the temperature indicator to crystallize. On the other hand, the second temperature detection material in Figure 11B did not change color at all. This confirmed the process by which the first temperature detection material changes color as a result of the accumulation of temperature and time at temperatures above the control temperature.
　次に、再び温度インジケータ作製後、１分以内に物品の管理温度として想定し、示温材のガラス転移点以下である０℃に５分保持した後、３０℃/分で示温材の融点（１１０℃程度）以上の１５０℃まで昇温し、その過程での温度インジケータの色濃度の温度依存性を観察した。その結果を、図１３Ａ及び図１３Ｂ並びに図１４に示す。図１３Ａ及び図１３Ｂの画像並びに図１４の色濃度データより、図１３Ａの第１温度検知材料が２５℃近傍から変色開始し、そのまま顕色状態を保持した状態で、第２温度検知材料が８０℃近傍から変色開始した。その後、第１温度検知材料が示温材の融点の１１０℃近傍より消色し、色が初期化される様子が確認された。これにより、第１温度検知材料の初期化が起こる前に、第２温度検知材料が高温加熱により変色する過程が確認できた。 Next, after preparing the temperature indicator again, the temperature was kept at 0°C, which is below the glass transition point of the temperature indicator, for 5 minutes within 1 minute, assuming that the temperature is the management temperature of the item, and then the temperature was raised at 30°C/min to 150°C, which is above the melting point of the temperature indicator (approximately 110°C), and the temperature dependency of the color density of the temperature indicator during this process was observed. The results are shown in Figures 13A, 13B, and 14. From the images in Figures 13A and 13B and the color density data in Figure 14, the first temperature detection material in Figure 13A began to change color at approximately 25°C, and while maintaining the color development state, the second temperature detection material began to change color at approximately 80°C. It was then confirmed that the first temperature detection material lost color near the melting point of the temperature indicator, 110°C, and the color was initialized. This confirmed the process in which the second temperature detection material changed color due to high-temperature heating before the initialization of the first temperature detection material occurred.
　次に、再び温度インジケータ作製後、１分以内に物品の管理温度として想定し、示温材のガラス転移点以下である０℃に５分保持した後、１５℃、２５℃、３５℃、４５℃、５５℃、６５℃、７５℃、８５℃、９５℃、１０５℃、１１５℃の各温度のホットプレートに速やかに静置した際の温度インジケータの色濃度の時間変化を観察した。その結果を、図１５Ａ及び図１５Ｂに示す。図１５Ａの第１温度検知材料の変色速度が最も速くなったのは５５℃であり、図１５Ｂの第２温度検知材料の変色開始は８５℃以上から見られた。すなわち、第１温度検知材料の変色速度の極大値Ｔ１は５５℃近傍であり、第２温度検知材料の変色開始温度をＴ２は７５℃～８５℃の間にあることが分かった。これにより、Ｔ１≦Ｔ２の関係が成立し、Ｔ２はＴ１より２０～３０℃程度高いことが確認できた。 Next, after preparing the temperature indicator again, the temperature was kept at 0°C, which is below the glass transition point of the temperature indicator, for 5 minutes, assuming that the temperature is the management temperature of the item, and then the temperature indicator was quickly placed on a hot plate at each of the following temperatures: 15°C, 25°C, 35°C, 45°C, 55°C, 65°C, 75°C, 85°C, 95°C, 105°C, and 115°C. The color density of the temperature indicator was observed over time. The results are shown in Figures 15A and 15B. The color change rate of the first temperature detection material in Figure 15A was the fastest at 55°C, and the color change of the second temperature detection material in Figure 15B began at 85°C or higher. In other words, it was found that the maximum color change rate T1 of the first temperature detection material was near 55°C, and the color change start temperature T2 of the second temperature detection material was between 75°C and 85°C. This confirmed that the relationship T1≦T2 was established, and that T2 was about 20 to 30°C higher than T1.
　以上より、本実施例に係る温度インジケータは、ある温度域において、時間と温度の積算で色が変化することで温度検知可能であり、その温度域以上の温度において、色が急峻に変化することで異常加熱されたことを検知可能であることが確認できた。
<<変形例>>
　本発明は上記実施形態及び実施例に限定されることなく、本発明の範囲内において種々の変形例を採用することができる。例えば、上記実施形態において、複数の第１温度検知材料及び複数の第２温度検知材料は、基材上に配置されるようにしてもよく、その場合、第３者に簡単に初期化されてしまうことを防ぐ観点から、近接する第１温度検知材料及び第２温度検知材料が１組以上存在するようにしてもよく、全ての第１温度検知材料のそれぞれが、少なくとも一つの第２温度検知材料に近接していることが好ましい。例えば、上記実施形態において、第２温度検知材料は、第１温度検知材料のガラス転移点と第１温度検知材料の融点との間の真ん中の温度である中間温度以上であり、且つ、第１温度検知材料の融点以下である温度範囲内に、第２温度検知材料の色変化が開始する温度である色変化開始温度を有していてもよい。 From the above, it was confirmed that the temperature indicator of this embodiment can detect temperature within a certain temperature range by changing color as a result of the accumulation of time and temperature, and can detect abnormal heating by a sudden change in color at temperatures above that temperature range.
<<Modifications>>
The present invention is not limited to the above-mentioned embodiment and examples, and various modifications can be adopted within the scope of the present invention. For example, in the above-mentioned embodiment, the plurality of first temperature detection materials and the plurality of second temperature detection materials may be arranged on a substrate, and in that case, from the viewpoint of preventing easy initialization by a third party, one or more pairs of adjacent first temperature detection materials and second temperature detection materials may be present, and it is preferable that each of all the first temperature detection materials is adjacent to at least one second temperature detection material. For example, in the above-mentioned embodiment, the second temperature detection material may have a color change start temperature, which is a temperature at which the color change of the second temperature detection material starts, within a temperature range that is equal to or higher than an intermediate temperature that is the middle temperature between the glass transition point of the first temperature detection material and the melting point of the first temperature detection material, and is equal to or lower than the melting point of the first temperature detection material.
　１…第１温度検知材料、２…示温材、３…マトリックス材、４…温度インジケータ、５…基材、６…第２温度検知材料、７…透明基材および透明性のある接着剤 1...First temperature detection material, 2...Temperature indicator, 3...Matrix material, 4...Temperature indicator, 5...Substrate, 6...Second temperature detection material, 7...Transparent substrate and transparent adhesive

Claims (15)

  1. 　非晶質の結晶化現象により色変化する第１温度検知材料と、
    　前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内で不可逆的に色変化する第２温度検知材料と、
    　を含む、
    　温度インジケータ。     A first temperature detection material that changes color due to an amorphous crystallization phenomenon;
    a second temperature sensing material that irreversibly changes color within a temperature range that is higher than the glass transition point of the first temperature sensing material and lower than the melting point of the first temperature sensing material;
    including,
    Temperature indicator.
  2. 　請求項１に記載の温度インジケータにおいて、
    　前記第１温度検知材料は、
    　前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内に、色変化速度が最大値になる色変化速度最大温度を有する、
    　温度インジケータ。     2. The temperature indicator of claim 1,
    The first temperature sensing material is
    a color change rate maximum temperature at which the color change rate is maximum within a temperature range that is higher than the glass transition point of the first temperature detection material and lower than the melting point of the first temperature detection material;
    Temperature indicator.
  3. 　請求項１に記載の温度インジケータにおいて、
    　前記第２温度検知材料は、
    　前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内に、前記第２温度検知材料の色変化が開始する温度である色変化開始温度を有する、
    　温度インジケータ。     2. The temperature indicator of claim 1,
    The second temperature sensing material is
    a color change onset temperature, which is a temperature at which a color change of the second temperature detection material starts, within a temperature range that is higher than the glass transition point of the first temperature detection material and lower than the melting point of the first temperature detection material;
    Temperature indicator.
  4. 　請求項２に記載の温度インジケータにおいて、
    　前記第２温度検知材料は、
    　前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内に、前記第２温度検知材料の色変化が開始する温度である色変化開始温度を有し、
    　前記第１温度検知材料の前記色変化速度最大温度は、前記第２温度検知材料の前記色変化開始温度以下である、
    　温度インジケータ。     3. The temperature indicator according to claim 2,
    The second temperature sensing material is
    a color change onset temperature at which a color change of the second temperature detection material starts is within a temperature range that is higher than the glass transition point of the first temperature detection material and lower than the melting point of the first temperature detection material;
    The color change rate maximum temperature of the first temperature detection material is equal to or lower than the color change start temperature of the second temperature detection material.
    Temperature indicator.
  5. 　請求項２に記載の温度インジケータにおいて、
    　前記第２温度検知材料は、
    　前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内に、前記第２温度検知材料の色変化が開始する温度である色変化開始温度を有し、
    　前記第２温度検知材料の前記色変化開始温度は、
    　前記第１温度検知材料の前記色変化速度最大温度から２０℃だけ低い第１温度以上であり、且つ、前記第１温度検知材料の前記色変化速度最大温度から６０℃だけ高い第２温度以下である温度範囲内にある、
    　温度インジケータ。     3. The temperature indicator according to claim 2,
    The second temperature sensing material is
    a color change onset temperature at which a color change of the second temperature detection material starts is within a temperature range that is higher than the glass transition point of the first temperature detection material and lower than the melting point of the first temperature detection material;
    The color change start temperature of the second temperature detecting material is
    Within a temperature range that is equal to or higher than a first temperature that is 20° C. lower than the maximum color change rate temperature of the first temperature sensing material and equal to or lower than a second temperature that is 60° C. higher than the maximum color change rate temperature of the first temperature sensing material.
    Temperature indicator.
  6. 　請求項５に記載の温度インジケータにおいて、
    　前記第１温度検知材料の前記ガラス転移点は－４０℃以上６０℃以下であり、前記第１温度検知材料の前記融点は、６０℃以上１５０℃以下であり、且つ、前記ガラス転移点と前記融点との温度差は１００℃以上１５０℃以下である、
    　温度インジケータ。     6. The temperature indicator according to claim 5,
    The glass transition point of the first temperature detection material is −40° C. or more and 60° C. or less, the melting point of the first temperature detection material is 60° C. or more and 150° C. or less, and the temperature difference between the glass transition point and the melting point is 100° C. or more and 150° C. or less.
    Temperature indicator.
  7. 　請求項１に記載の温度インジケータにおいて、
    　前記第２温度検知材料の色変化が開始する温度である色変化開始温度は、
    　前記第１温度検知材料の前記ガラス転移点と前記第１温度検知材料の前記融点との間の真ん中の温度である中間温度以上であり、且つ、前記第１温度検知材料の前記融点以下である温度範囲内にある、
    　温度インジケータ。     2. The temperature indicator of claim 1,
    The color change onset temperature, which is the temperature at which the color change of the second temperature detection material starts, is
    The temperature range is equal to or higher than an intermediate temperature that is a middle temperature between the glass transition point of the first temperature detection material and the melting point of the first temperature detection material, and is equal to or lower than the melting point of the first temperature detection material.
    Temperature indicator.
  8. 　請求項１に記載の温度インジケータにおいて、
    　前記第１温度検知材料は、ロイコ染料、顕色剤及び消色剤を含む示温材を含む、
    　温度インジケータ。     2. The temperature indicator of claim 1,
    The first temperature detection material includes a temperature indicator including a leuco dye, a color developer, and a decolorizer.
    Temperature indicator.
  9. 　請求項８に記載の温度インジケータにおいて、
    　前記第１温度検知材料は、マトリックス材を含む、
    　温度インジケータ。     9. The temperature indicator of claim 8,
    The first temperature sensing material includes a matrix material.
    Temperature indicator.
  10. 　請求項９に記載の温度インジケータにおいて、
    　前記第１温度検知材料は、前記マトリックス材中に前記示温材が分散した相分離構造を有する、
    　温度インジケータ。     10. The temperature indicator of claim 9,
    The first temperature detection material has a phase-separated structure in which the temperature indicating material is dispersed in the matrix material.
    Temperature indicator.
  11. 　請求項１に記載の温度インジケータにおいて、
    　前記第１温度検知材料及び前記第２温度検知材料を、直接的又は間接的に支持する基材を含む、
    　温度インジケータ。     2. The temperature indicator of claim 1,
    A substrate that directly or indirectly supports the first temperature sensing material and the second temperature sensing material.
    Temperature indicator.
  12. 　請求項１に記載の温度インジケータにおいて、
    　前記第２温度検知材料は、感熱材料である、
    　温度インジケータ。     2. The temperature indicator of claim 1,
    the second temperature sensing material is a heat sensitive material;
    Temperature indicator.
  13. 　請求項１２に記載の温度インジケータにおいて、
    　前記感熱材料は、感熱紙、感熱シート、感熱塗料、感熱インク、又は、感熱マイクロカプセルである、
    　温度インジケータ。     13. The temperature indicator of claim 12,
    The heat-sensitive material is heat-sensitive paper, heat-sensitive sheet, heat-sensitive paint, heat-sensitive ink, or heat-sensitive microcapsules.
    Temperature indicator.
  14. 　請求項１に記載の温度インジケータにおいて、
    　前記第１温度検知材料と前記第２温度検知材料とが近接している、
    　温度インジケータ。     2. The temperature indicator of claim 1,
    The first temperature sensing material and the second temperature sensing material are in close proximity to each other.
    Temperature indicator.
  15. 　非晶質の結晶化現象により色変化する第１温度検知材料と、
    　前記第１温度検知材料のガラス転移点よりも高く、且つ、前記第１温度検知材料の融点よりも低い温度範囲内で不可逆的に色変化する第２温度検知材料と、
    　を含む温度インジケータを製造する温度インジケータ製造方法であって、
    　前記第１温度検知材料の色を初期化した後、前記第１温度検知材料の変色が開始する前に、前記第２温度検知材料を前記第１温度検知材料の近接位置に付与する、
    　温度インジケータ製造方法。     A first temperature detection material that changes color due to an amorphous crystallization phenomenon;
    a second temperature sensing material that irreversibly changes color within a temperature range that is higher than the glass transition point of the first temperature sensing material and lower than the melting point of the first temperature sensing material;
    A method for manufacturing a temperature indicator comprising the steps of:
    applying the second temperature sensing material to a position adjacent to the first temperature sensing material after initializing the color of the first temperature sensing material and before the first temperature sensing material begins to change color;
    Temperature indicator manufacturing method.
PCT/JP2022/047874 2022-12-26 2022-12-26 Temperature indicator and method for producing temperature indicator WO2024142146A1 (en)

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JP2019128166A (en) * 2018-01-22 2019-08-01 株式会社日立製作所 Temperature detection label and article management system using the same
JP2019127498A (en) * 2018-01-22 2019-08-01 株式会社日立製作所 Temperature detection ink, initialization method thereof, temperature indicator and object management system
JP2020003281A (en) * 2018-06-27 2020-01-09 セイコーインスツル株式会社 Temperature detection device, temperature detection device issuance device, and method for temperature detection
US20220178761A1 (en) * 2020-12-08 2022-06-09 Temptime Corporation Time-temperature exposure indicator with delayed threshold response

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019128166A (en) * 2018-01-22 2019-08-01 株式会社日立製作所 Temperature detection label and article management system using the same
JP2019127498A (en) * 2018-01-22 2019-08-01 株式会社日立製作所 Temperature detection ink, initialization method thereof, temperature indicator and object management system
JP2020003281A (en) * 2018-06-27 2020-01-09 セイコーインスツル株式会社 Temperature detection device, temperature detection device issuance device, and method for temperature detection
US20220178761A1 (en) * 2020-12-08 2022-06-09 Temptime Corporation Time-temperature exposure indicator with delayed threshold response

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