Reversible thermochromic print, reversible thermochromic print set

Abstract

To provide a reversible thermochromic print suitable for training use, intellectual use, and anti-counterfeiting use, which satisfy unexpectedness and playability of discoloration, because a reversible thermochromic pattern before discoloration and a non-discoloring pattern are difficult to discriminate visually or with hand, and therefore, a user cannot predict which pattern discolor.SOLUTION: A reversible thermochromic print 1 includes, on a surface of a support 2, a reversible thermochromic pattern 3 containing a reversible thermochromic material and selected from characters, symbols, and designs, and a non-discoloring pattern 4 containing a non-discoloring coloring agent and selected from characters, symbols, and designs related to the reversible thermochromic pattern, where thicknesses of the reversible thermochromic pattern and non-discoloring pattern are approximately the same. A reversible thermochromic print set consists of the reversible thermochromic print and a friction body.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a reversible thermochromic printed matter and a set of reversible thermochromic printed matter. More specifically, the present invention relates to a reversible thermochromic printed matter and a set of reversible thermochromic printed matter each having a reversible thermochromic design and a non-color-changing design. [Background technology]

[0002] 2. Description of the Related Art Prints having both a reversible thermochromic design and a non-chromic design on a support have been disclosed (see, for example, Patent Documents 1 and 2). In the above-mentioned printed matter, the reversible thermochromic pattern fades, develops or changes color due to temperature changes, allowing the visual appearance of a unique change in appearance. However, the reversible thermochromic microcapsule pigment contained in the reversible thermochromic pattern has a large particle diameter, which gives the pattern thickness, while the other non-color-changing pattern is not. As a result, the reversible thermochromic pattern and the non-color-changing pattern can be distinguished by sight or touch, which can detract from the appeal of the color change. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Microfilm of Utility Model Application No. 59-27988 (Utility Model Application No. 60-138760) Summary of the Invention [Problem to be solved by the invention]

[0004] To provide a reversible thermochromic printed matter and a set of reversible thermochromic printed matter in which it is difficult for a user to distinguish between a reversible thermochromic design and a non-color-changing design before color change in this type of printed matter, and therefore it is not possible to predict which design will change color. [Means for solving the problem]

[0005] The present invention requires a reversible thermochromic printed matter having, on the surface of a support, a reversible thermochromic pattern containing a reversible thermochromic material and selected from letters, symbols and pictures, and a non-color-changing pattern containing a non-color-changing colorant and selected from letters, symbols and pictures related to the reversible thermochromic pattern, and characterized in that the reversible thermochromic pattern and the non-color-changing pattern are approximately the same thickness. Furthermore, the thickness (D1) of the reversible thermochromic pattern is 2 to 100 μm, and the thickness (D2) of the non-chromic pattern satisfies the following formula (1): 0.7≦D2 / D1≦1.3 (1) The reversible thermochromic material in the reversible thermochromic pattern is a reversible thermochromic microcapsule pigment containing a reversible thermochromic composition that changes color from colored to colorless and is composed of at least (a) an electron-donating organic color-forming compound, (b) an electron-accepting compound, and (c) a reaction medium that controls the color reactions of (a) and (b). The non-color-changing pattern contains resin particles or microcapsule pigments, and the average particle diameters of the reversible thermochromic microcapsule pigment and the resin particles or microcapsule pigment are approximately the same. The non-color-changing pattern contains a non-color-changing colorant in the resin particles or microcapsule pigment, or the surfaces of the resin particles or microcapsule pigment are coated with a non-color-changing colorant. The average particle diameter (L1) of the reversible thermochromic microcapsule pigment contained in the reversible thermochromic pattern and the average particle diameter (L2) of the resin particles or microcapsule pigment contained in the non-color-changing pattern are expressed by the following formula (2). 0.7≦L2 / L1≦1.3 (2) The requirements are that the color of the reversible thermochromic material in the colored state and the color of the non-color-changing pattern are the same or similar colors; the reversible thermochromic microencapsulated pigment exhibits hysteresis characteristics with respect to the color concentration-temperature curve, exhibiting alternation between a colored state and a colorless state, and in the process of temperature increase from the colored state, begins to fade when temperature t3 is reached and becomes completely colorless in a temperature range of t4 or higher, which is higher than temperature t3; and in the process of temperature decrease from the colorless state, begins to color when temperature t2, which is lower than temperature t3, is reached and becomes completely colored in a temperature range of t1 or lower, which is lower than temperature t2, and temperature t4 is in the range of 30 to 90°C; and a transparent metallic gloss layer is provided to cover the reversible thermochromic pattern and the non-color-changing pattern. Further requirements include a reversible thermochromic printed material set consisting of the reversible thermochromic printed material and a friction body, and a reversible thermochromic printed material set consisting of the reversible thermochromic printed material and a writing instrument equipped with a friction member. Effect of the Invention

[0006] To provide a reversible thermochromic printed matter and a set of reversible thermochromic printed matter suitable for educational purposes, intellectual training purposes, and anti-counterfeiting purposes, which satisfy the unexpectedness and playfulness of the color change, since a user cannot predict which pattern will change color because it is difficult to distinguish between a reversible thermochromic pattern and a non-color change pattern before color change by visual inspection or touch. [Brief description of the drawings]

[0007] [Figure 1] 1 is a graph illustrating hysteresis characteristics in a color density-temperature curve of a heat-discolorable, reversible thermochromic composition. [Diagram 2] 1 is a graph illustrating the hysteresis characteristics in a color density-temperature curve of a reversible thermochromic composition having color memory properties. [Diagram 3] 1 is a graph illustrating hysteresis characteristics in a color density-temperature curve of a reversible thermochromic composition that develops color upon heating. [Figure 4] 1 is an explanatory vertical cross-sectional view showing one embodiment of a reversible thermochromic printed matter of the present invention. [Diagram 5]FIG. 2 is an explanatory vertical cross-sectional view showing another embodiment of a reversible thermochromic printed matter of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The reversible thermochromic printed matter is a printed matter having a reversible thermochromic design and a non-thermochromic design on the surface of a support such as paper, synthetic paper, or fabric. The material of the support is not particularly limited, and examples thereof include paper, synthetic paper, synthetic leather, plastic, glass, ceramics, metal, wood, and stone, with paper and synthetic paper being preferred. The shape of the support is not limited to a flat shape, and may be uneven.

[0009] The reversible thermochromic design is a design selected from characters, symbols and pictures, and comprises a reversible thermochromic material. The designs include designs of people, animals, plants, fruits, food products, vehicles, buildings, celestial bodies, patterns, and the like. Examples of the reversible thermochromic material include inorganic materials such as Ag2HgI4 and Cu2HgI4, liquid crystals, resin particles containing a reversible thermochromic composition, and reversible thermochromic microencapsulated pigments (reversible thermochromic pigments) encapsulating a reversible thermochromic composition, and reversible thermochromic microencapsulated pigments are preferably used.

[0010] The reversible thermochromic composition may be a thermally decolorizable (decolorizing by heating and coloring by cooling) reversible thermochromic composition containing at least three essential components: (i) an electron-donating color-forming organic compound, (ii) an electron-accepting compound, and (iii) a reaction medium that determines the temperature at which the color-forming reaction between the two occurs. The reversible thermochromic composition may be a reversible thermochromic composition of a heat-discoloring type (discolored by heating and colored by cooling) having a relatively small hysteresis width (ΔH) of 1 to 7° C., which is described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, etc. and which changes color around a certain temperature (discoloration point), exhibits a discolored state in a temperature range above the high-temperature discoloration point, and exhibits a colored state in a temperature range below the low-temperature discoloration point, and of the two states, only one specific state exists in the room temperature range, and the other state is maintained while the heat or cold required to express that state is applied, but returns to the state exhibited in the room temperature range when the application of the heat or cold is removed (see FIG. 1).

[0011] In addition, hysteresis width (ΔH) described in JP-B-4-17154, JP-A-7-179777, JP-A-7-33997, JP-A-8-39936, JP-A-2005-1369, JP-A-2008-280523, etc. shows a relatively large characteristic of 8°C to 80°C, that is, the shape of the curve plotting the change in color density due to temperature change is as follows: A reversible thermochromic composition of the heat-discoloring type (discolors when heated and develops color when cooled) that has color memory in a specific temperature range [temperature range between t2 and t3 (temperature range where two phases are substantially maintained)], in which the color changes along a route that is significantly different when the temperature is lowered from a higher temperature side than the discoloration temperature range and the colored state is in a low temperature range below the complete color-developing temperature (t1) or in a decolored state is in a high temperature range above the complete decolorization temperature (t4) (see Figure 2).

[0012] The hysteresis characteristic in the color density-temperature curve of the reversible thermochromic composition will now be described. In Fig. 2, the vertical axis represents color density, and the horizontal axis represents temperature. The change in color density due to temperature change progresses along the arrow. Here, A is a point indicating the density at temperature t4 (hereinafter referred to as complete decolorization temperature) where a completely decolorized state is reached, B is a point indicating the density at temperature t3 (hereinafter referred to as decolorization onset temperature) where decolorization begins, C is a point indicating the density at temperature t2 (hereinafter referred to as color development onset temperature) where color development begins, and D is a point indicating the density at temperature t1 (hereinafter referred to as complete color development temperature) where a completely colored state is reached. The discoloration temperature range is the temperature range between t1 and t4, and can exhibit either a colored state or a decolored state. The temperature range between t2 and t3, which is the region with a large difference in color density, is the actual discoloration temperature range. The length of the line segment EF is a measure of the contrast of the discoloration, and the length of the line segment HG passing through the midpoint of the line segment EF is a temperature range indicating the degree of hysteresis (hereinafter referred to as hysteresis range ΔH). If this ΔH value is small, only one of the two states before and after the discoloration can exist in the room temperature range. If the ΔH value is large, it is easy to maintain each state before and after the discoloration.

[0013] Components (a), (b) and (c) contained in the reversible thermochromic composition will be specifically described below. The component (A), ie, the electron-donating organic color-forming compound, is a component that determines the color, and is a compound that develops color by donating electrons to the component (B), which is a color developer. Examples of the electron-donating color-forming organic compound include phthalide compounds, fluoran compounds, styrinquinoline compounds, diazarhodamine lactone compounds, pyridine compounds, quinazoline compounds, and bisquinazoline compounds. Of these, phthalide compounds, fluoran compounds, styrinquinoline compounds, and diazarhodamine lactone compounds are preferred. Examples of the phthalide compound include diphenylmethane phthalide compounds, phenylindolyl phthalide compounds, indolyl phthalide compounds, diphenylmethane azaphthalide compounds, phenylindolyl azaphthalide compounds, and derivatives thereof. Among these, phenylindolyl azaphthalide compounds and derivatives thereof are preferred. Examples of these compounds are given below. 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide, 3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide, 3,3-bis(1-n-butyl-2-methylindol-3-yl)phthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(2-ethoxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-(2-hexyloxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-[2-ethoxy-4-(N-ethylanilino)phenyl]-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-(2-acetamido-4-diethylaminophenyl)-3-(1-propylindol-3-yl)-4-azaphthalide, 3,6-bis(diphenylamino)fluoran, 3,6-dimethoxyfluoran, 3,6-di-n-butoxyfluoran, 2-methyl-6-(N-ethyl-Np-tolylamino)fluoran, 3-chloro-6-cyclohexylaminofluoran, 2-methyl-6-cyclohexylaminofluoran, 2-(2-chloroamino)-6-dibutylaminofluoran, 2-(2-chloroanilino)-6-di-n-butylaminofluoran, 2-(3-trifluoromethylanilino)-6-diethylaminofluoran, 2-(3-trifluoromethylanilino)-6-dipentylaminofluoran, 2-(dibenzylamino)-6-diethylaminofluoran, 2-(N-methylanilino)-6-(N-ethyl-Np-tolylamino)fluoran, 1,3-dimethyl-6-diethylaminofluoran, 2-chloro-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methoxy-6-diethylaminofluoran, 2-anilino-3-methyl-6-di-n-butylaminofluoran, 2-anilino-3-methoxy-6-di-n-butylaminofluoran, 2-xylidino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-(N-ethyl-Np-tolylamino)fluoran, 1,2-Benz-6-diethylaminofluoran, 1,2-Benz-6-(N-ethyl-N-isobutylamino)fluoran, 1,2-Benz-6-(N-ethyl-N-isoamylamino)fluoran, 2-(3-methoxy-4-dodecoxystyryl)quinoline, Spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1′(3′H)isobenzofuran]-3′-one, 2-(diethylamino)-8-(diethylamino)-4-methyl, Spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1′(3′H)isobenzofuran]-3′-one, 2-(di-n-butylamino)-8-(di-n-butylamino)-4-methyl, Spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1′(3′H)isobenzofuran]-3′-one, 2-(di-n-butylamino)-8-(diethylamino)-4-methyl, Spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1′(3′H)isobenzofuran]-3′-one, 2-(di-n-butylamino)-8-(N-ethyl-Ni-amylamino)-4-methyl, Spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1′(3′H)isobenzofuran]-3′-one, 2-(dibutylamino)-8-(dipentylamino)-4-methyl, 4,5,6,7-tetrachloro-3-[4-(dimethylamino)-2-methoxyphenyl]-3-(1-butyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-tetrachloro-3-[4-(diethylamino)-2-ethoxyphenyl]-3-(1-ethyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-tetrachloro-3-[4-(diethylamino)-2-ethoxyphenyl]-3-(1-pentyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-tetrachloro-3-[4-(diethylamino)-2-methylphenyl]-3-(1-ethyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone, 3',6'-bis[phenyl(2-methylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one, 3',6'-bis[phenyl(3-methylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one, 3',6'-bis[phenyl(3-ethylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one, 2,6-bis(2′-ethyloxyphenyl)-4-(4′-dimethylaminophenyl)pyridine, 2,6-bis(2′,4′-diethyloxyphenyl)-4-(4′-dimethylaminophenyl)pyridine, 2-(4′-dimethylaminophenyl)-4-methoxy-quinazoline, 4,4'-(Ethylenedioxy)-bis[2-(4-diethylaminophenyl)quinazoline] etc. can be mentioned. In addition to the above-mentioned compounds having a substituent on the phenyl group forming the xanthene ring, the fluorans may also be compounds that have a substituent on the phenyl group forming the xanthene ring and also have a substituent (e.g., an alkyl group such as a methyl group, or a halogen atom such as a chloro group) on the phenyl group forming the lactone ring, and exhibit a blue or black color.

[0014] The component (b), ie, the electron accepting compound, is a compound that accepts electrons from the component (a) and functions as a developer for the component (a). The electron-accepting compound may be a compound selected from a group of compounds having an active proton and derivatives thereof, a group of pseudo-acidic compounds (a group of compounds which are not acids but act as an acid in the composition to cause component (A) to develop color), a group of compounds having an electron vacancy, and the like. Among these, a compound selected from a group of compounds having an active proton is preferred. Examples of compounds having an active proton and derivatives thereof include compounds having a phenolic hydroxyl group and metal salts thereof, carboxylic acids and metal salts thereof, preferably aromatic carboxylic acids, aliphatic carboxylic acids having 2 to 5 carbon atoms and metal salts thereof, acidic phosphate esters and metal salts thereof, as well as azole compounds and derivatives thereof, and 1,2,3-triazole and derivatives thereof. Among these, compounds having a phenolic hydroxyl group are preferred because they can exhibit effective thermochromic properties. The compounds having a phenolic hydroxyl group include a wide range of compounds from monophenol compounds to polyphenol compounds, and further include bis-type and tris-type phenols and phenol-aldehyde condensation resins. Among the compounds having a phenolic hydroxyl group, those having at least two benzene rings are preferred. In addition, these compounds may have a substituent, and examples of the substituent include an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group, a carboxyl group and its ester or amide group, a halogen group, and the like. Examples of the metal contained in the metal salt of the compound having an active proton include sodium, potassium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, lead, and molybdenum.

[0015] Some specific examples are given below. Phenol, o-cresol, tertiary butyl catechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, n-butyl p-hydroxybenzoate, n-octyl p-hydroxybenzoate, resorcinol, dodecyl gallate, 4,4-dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl)sulfide, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)propane, 1 ,1-bis(4-hydroxyphenyl)n-butane, 1,1-bis(4-hydroxyphenyl)n-pentane, 1,1-bis(4-hydroxyphenyl)n-hexane, 1,1-bis(4-hydroxyphenyl)n-heptane, 1,1-bis(4-hydroxyphenyl)n-octane, 1,1-bis(4-hydroxyphenyl)n-nonane, 1,1-bis(4-hydroxyphenyl)n-decane, 1,1-bis(4-hydroxyphenyl)n-dodecane, 1,1-bis(4-hydroxyphenyl)-2-methylpropane, 1,1-bis(4-hydroxyphenyl)n-butyl ... 1,1-bis(4-hydroxyphenyl)-3-methylbutane, 1,1-bis(4-hydroxyphenyl)-3-methylpentane, 1,1-bis(4-hydroxyphenyl)-2,3-dimethylpentane, 1,1-bis(4-hydroxyphenyl)-2-ethylbutane, 1,1-bis(4-hydroxyphenyl)-2-ethylhexane, 1,1-bis(4-hydroxyphenyl)-3,7-dimethyloctane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1-phenyl-1,1-bi bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)n-butane, 2,2-bis(4-hydroxyphenyl)n-pentane, 2,2-bis(4-hydroxyphenyl)n-hexane, 2,2-bis(4-hydroxyphenyl)n-heptane, 2,2-bis(4-hydroxyphenyl)n-octane, 2,2-bis(4-hydroxyphenyl)n-nonane, 2,2-bis(4-hydroxyphenyl)n-decane, 2,2-bis(4-hydroxyphenyl)n-dodecane, 2,2-bis(4-hydroxyphenyl)ethylpropionate, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxyphenyl)-4-methylhexane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,1-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, bis(2-hydroxyphenyl)methane, 1,1,1-tris(4-hydroxyphenyl)ethane, 3,3-bis(3-methyl-4-hydroxyphenyl)butane, etc. The compound having a phenolic hydroxyl group is capable of exhibiting the most effective thermal discoloration properties, but it may also be a compound selected from aromatic carboxylic acids and aliphatic carboxylic acids having 2 to 5 carbon atoms, carboxylic acid metal salts, acidic phosphate esters and their metal salts, 1,2,3-triazole and its derivatives.

[0016] The component (iii) of the reaction medium that reversibly induces an electron donor-acceptor reaction by the components (a) and (b) in a specific temperature range will now be described. Examples of the component (iii) include alcohols, esters, ketones, ethers, and acid amides. When component (C) is used for the microencapsulation and secondary processing described below, compounds having a carbon number of 10 or more are preferably used in order to stably retain the component in the capsule, since low molecular weight compounds tend to evaporate outside the capsule when subjected to high heat treatment. As the alcohols, aliphatic monohydric saturated alcohols having 10 or more carbon atoms are effective, and specific examples thereof include decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, eicosyl alcohol, docosyl alcohol, etc.

[0017] As the esters, esters having 10 or more carbon atoms are effective, and examples thereof include esters obtained from any combination of a monovalent carboxylic acid having an aliphatic and an alicyclic or aromatic ring and a monohydric alcohol having an aliphatic and an alicyclic or aromatic ring, esters obtained from any combination of a polyvalent carboxylic acid having an aliphatic and an alicyclic or aromatic ring and a monohydric alcohol having an aliphatic and an alicyclic or aromatic ring, esters obtained from any combination of a monovalent carboxylic acid having an aliphatic and an alicyclic or aromatic ring and a polyhydric alcohol having an aliphatic and an alicyclic or aromatic ring, Specific examples of the esters include ethyl caprylate, octyl caprylate, stearyl caprylate, myristyl caprate, docosyl caprate, 2-ethylhexyl laurate, n-decyl laurate, 3-methylbutyl myristate, myristyl myristate, cetyl myristate, isopropyl palmitate, neopentyl palmitate, nonyl palmitate, cyclohexyl palmitate, n-butyl stearate, 2-methylbutyl stearate, and 3,5,5-trimethylhexyl stearate. , n-undecyl stearate, pentadecyl stearate, stearyl stearate, cyclohexylmethyl stearate, isopropyl behenate, hexyl behenate, lauryl behenate, behenyl behenate, cetyl benzoate, stearyl p-tert-butylbenzoate, dimyristyl phthalate, distearyl phthalate, dimyristyl oxalate, dicetyl oxalate, dicetyl malonate, dilauryl succinate, dilauryl glutarate, diundecyl adipate, dilauryl azelaate, di-(n-noni) sebacate 1,18-octadecylmethylenedicarboxylate dineopentyl, ethylene glycol dimyristate, propylene glycol dilaurate, propylene glycol distearate, hexylene glycol dipalmitate, 1,5-pentanediol distearate, 1,2,6-hexanetriol trimyristate, 1,4-cyclohexanediol didecyl, 1,4-cyclohexanedimethanol dimyristate, xylene glycol dicaprinate, xylene glycol distearate, and the like.

[0018] Also effective are esters of saturated fatty acids and branched fatty alcohols, esters of unsaturated fatty acids or branched or substituted saturated fatty acids and branched fatty alcohols or fatty alcohols having 16 or more carbon atoms, and ester compounds selected from cetyl butyrate, stearyl butyrate, and behenyl butyrate. Specifically, 2-ethylhexyl butyrate, 2-ethylhexyl behenate, 2-ethylhexyl myristate, 2-ethylhexyl caprate, 3,5,5-trimethylhexyl laurate, 3,5,5-trimethylhexyl palmitate, 3,5,5-trimethylhexyl stearate, 2-methylbutyl caproate, 2-methylbutyl caprylate, 2-methylbutyl caprate, 1-ethylpropyl palmitate, 1-ethylpropyl stearate, 1-ethylpropyl behenate, 1-ethylpropyl laurate, xyl, 1-ethylhexyl myristate, 1-ethylhexyl palmitate, 2-methylpentyl caproate, 2-methylpentyl caprylate, 2-methylpentyl caprate, 2-methylpentyl laurate, 2-methylbutyl stearate, 2-methylbutyl stearate, 3-methylbutyl stearate, 1-methylheptyl stearate, 2-methylbutyl behenate, 3-methylbutyl behenate, 1-methylheptyl stearate, 1-methylheptyl behenate, 1-ethylpentyl caproate, 1-Ethylpentyl palmitate, 1-methylpropyl stearate, 1-methyloctyl stearate, 1-methylhexyl stearate, 1,1-dimethylpropyl laurate, 1-methylpentyl caprate, 2-methylhexyl palmitate, 2-methylhexyl stearate, 2-methylhexyl behenate, 3,7-dimethyloctyl laurate, 3,7-dimethyloctyl myristate, 3,7-dimethyloctyl palmitate, 3,7-dimethyloctyl stearate, 3,7-dimethyloctyl behenate Examples of suitable oleic acid esters include ethyl octyl, stearyl oleate, behenyl oleate, stearyl linoleate, behenyl linoleate, 3,7-dimethyloctyl erucate, stearyl erucate, isostearyl erucate, cetyl isostearate, stearyl isostearate, 2-methylpentyl 12-hydroxystearate, 2-ethylhexyl 18-bromostearinate, isostearyl 2-ketomyristate, 2-ethylhexyl 2-fluoromyristate, cetyl butyrate, stearyl butyrate, and behenyl butyrate.

[0019] Furthermore, in order to change color while exhibiting a large hysteresis characteristic with respect to the color density-temperature curve and to impart color memory depending on temperature change, carboxylic acid ester compounds exhibiting a ΔT value (melting point-cloud point) of 5° C. or more and less than 50° C. as described in JP-B-4-17154 may be mentioned, such as carboxylic acid esters containing a substituted aromatic ring in the molecule, esters of carboxylic acids containing an unsubstituted aromatic ring and aliphatic alcohols having 10 or more carbon atoms, carboxylic acid esters containing a cyclohexyl group in the molecule, esters of fatty acids having 6 or more carbon atoms and unsubstituted aromatic alcohols or phenols, esters of fatty acids having 8 or more carbon atoms and branched aliphatic alcohols, esters of dicarboxylic acids and aromatic alcohols or branched aliphatic alcohols, dibenzyl cinnamate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, dicetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearin, dimyristin, distearin, etc.

[0020] Fatty acid ester compounds obtained from an odd-numbered aliphatic monohydric alcohol having 9 or more carbon atoms and an aliphatic carboxylic acid having an even number of carbon atoms, and fatty acid ester compounds having a total of 17 to 23 carbon atoms obtained from n-pentyl alcohol or n-heptyl alcohol and an even-numbered aliphatic carboxylic acid having 10 to 16 carbon atoms are also effective. Specifically, n-pentadecyl acetate, n-tridecyl butyrate, n-pentadecyl butyrate, n-undecyl caproate, n-tridecyl caproate, n-pentadecyl caproate, n-nonyl caprylate, n-undecyl caprylate, n-tridecyl caprylate, n-pentadecyl caprylate, n-heptyl caprate, n-nonyl caprate, n-undecyl caprate, n-tridecyl caprate, n-pentadecyl caprate, n-pentyl laurate, n-heptyl laurate, n-nonyl laurate, n-undecyl laurate, n-tridecyl laurate, n-pentadecyl laurate, n-pentyl myristate, n-heptyl myristate, myristic Examples of the glyceryl stearate include n-nonyl myristate, n-undecyl myristate, n-tridecyl myristate, n-pentadecyl myristate, n-pentyl palmitate, n-heptyl palmitate, n-nonyl palmitate, n-undecyl palmitate, n-tridecyl palmitate, n-pentadecyl palmitate, n-nonyl stearate, n-undecyl stearate, n-tridecyl stearate, n-pentadecyl stearate, n-nonyl eicosanoate, n-undelsyl eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate, n-nonyl behenate, n-undecyl behenate, n-tridecyl behenate, and n-pentadecyl behenate.

[0021] As the ketones, aliphatic ketones having a total carbon number of 10 or more are effective, and examples thereof include 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, 5-undecanone, 2-dodecanone, 3-dodecanone, 4-dodecanone, 5-dodecanone, 2-tridecanone, 3-tridecanone, 2-tetradecanone, 2-pentadecanone, 8-pentadecanone, 2-hexadecanone, 3-hexadecanone, 9-heptadecanone, 2-pentadecanone, 2-octadecanone, 2-nonadecanone, 10-nonadecanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, laurone, stearone, and the like. Further, aryl alkyl ketones having a total carbon number of 12 to 24, for example, n-octadecanophenone, n-heptadecanophenone, n-hexadecanophenone, n-pentadecanophenone, n-tetradecanophenone, 4-n-dodecaacetophenone, n-tridecanophenone, 4-n-undecanoacetophenone, n-laurophenone, 4-n-decanoacetophenone, n-undecanophenone, 4-n-nonylacetophenone, n-decanophenone, 4-n-octylacetophenone, n ... nophenone, 4-n-heptylacetophenone, n-octanophenone, 4-n-hexylacetophenone, 4-n-cyclohexylacetophenone, 4-tert-butylpropiophenone, n-heptaphenone, 4-n-pentylacetophenone, cyclohexyl phenyl ketone, benzyl-n-butyl ketone, 4-n-butylacetophenone, n-hexanophenone, 4-isobutylacetophenone, 1-acetonaphthone, 2-acetonaphthone, cyclopentyl phenyl ketone, and the like.

[0022] As the ethers, aliphatic ethers having a total of 10 or more carbon atoms are effective, and examples thereof include dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, didodecyl ether, ditridecyl ether, ditetradecyl ether, dipentadecyl ether, dihexadecyl ether, dioctadecyl ether, decanediol dimethyl ether, undecanediol dimethyl ether, dodecanediol dimethyl ether, tridecanediol dimethyl ether, decanediol diethyl ether, and undecanediol diethyl ether.

[0023] Examples of acid amides include acetamide, propionic acid amide, butyric acid amide, caproic acid amide, caprylic acid amide, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, benzamide, caproic acid anilide, caprylic acid anilide, capric acid anilide, lauric acid anilide, myristic acid anilide, palmitic acid anilide, stearic acid anilide, behenic acid anilide, oleic acid anilide, erucic acid anilide, and caproic acid N-methylamide. Caprylic acid N-methylamide, capric acid N-methylamide, lauric acid N-methylamide, myristic acid N-methylamide, palmitic acid N-methylamide, stearic acid N-methylamide, behenic acid N-methylamide, oleic acid N-methylamide, erucic acid N-methylamide, lauric acid N-ethylamide, myristic acid N-ethylamide, palmitic acid N-ethylamide, stearic acid N-ethylamide, oleic acid N-ethylamide, lauric acid N-butylamide, myristic acid N-butylamide, palmitic acid N-butylamide, stearic acid N-ethylamide, Phosphoric acid N-butylamide, oleic acid N-butylamide, lauric acid N-octylamide, myristic acid N-octylamide, palmitic acid N-octylamide, stearic acid N-octylamide, oleic acid N-octylamide, lauric acid N-dodecylamide, myristic acid N-dodecylamide, palmitic acid N-dodecylamide, stearic acid N-dodecylamide, oleic acid N-dodecylamide, dilauric acid amide, dimyristic acid amide, dipalmitic acid amide, distearic acid amide, dioleic acid amide, trilauric acid amide, tri Myristic acid amide, tripalmitic acid amide, tristearic acid amide, trioleic acid amide, succinic acid amide, adipic acid amide, glutaric acid amide, malonic acid amide, azelaic acid amide, maleic acid amide, succinic acid N-methylamide, adipic acid N-methylamide, glutaric acid N-methylamide, malonic acid N-methylamide, azelaic acid N-methylamide, succinic acid N-ethylamide, adipic acid N-ethylamide, glutaric acid N-ethylamide, malonic acid N-ethylamide, azelaic acid N-ethylamide, succinic acid N-butylamide,Examples of the amides include adipic acid N-butylamide, glutaric acid N-butylamide, malonic acid N-butylamide, adipic acid N-octylamide, and adipic acid N-dodecylamide.

[0024] Furthermore, as the component (iii), a compound represented by the following general formula (1) can also be used. [ka] [In the formula, R1 represents a hydrogen atom or a methyl group, m represents an integer of 0 to 2, and either X1 or X2 represents -(CH2) n OCOR2 or -(CH2) n COOR2, the other represents a hydrogen atom, n represents an integer of 0 to 2, R2 represents an alkyl or alkenyl group having 4 or more carbon atoms, Y1 and Y2 represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, or a halogen, and r and p represent integers of 1 to 3. Among the compounds represented by the formula (1), when R1 is a hydrogen atom, a reversible thermochromic composition having a wider hysteresis width can be obtained, which is preferable, and further when R1 is a hydrogen atom and m is 0, it is more preferable. Among the compounds represented by formula (1), it is more preferable to use a compound represented by the following general formula (2). [ka] In the formula, R represents an alkyl or alkenyl group having 8 or more carbon atoms, preferably an alkyl group having 10 to 24 carbon atoms, and more preferably an alkyl group having 12 to 22 carbon atoms. Specific examples of the compound include 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, and 4-benzyloxyphenylethyl octadecanoate.

[0025] Furthermore, as the component (iii), a compound represented by the following general formula (3) can also be used. [ka] (In the formula, R represents an alkyl or alkenyl group having 8 or more carbon atoms, m and n each represent an integer of 1 to 3, and X and Y each represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen.) Specific examples of the compound include 1,1-diphenylmethyl octanoate, 1,1-diphenylmethyl nonanoate, 1,1-diphenylmethyl decanoate, 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.

[0026] Furthermore, a compound represented by the following general formula (4) can also be used as the component (iii). [ka] (In the formula, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, or a halogen atom, m represents an integer of 1 to 3, and n represents an integer of 1 to 20.) Examples of the compound include a diester of malonic acid and 2-[4-(4-chlorobenzyloxy)phenyl]ethanol, a diester of succinic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of succinic acid and 2-[4-(3-methylbenzyloxy)phenyl]ethanol, a diester of glutaric acid and 2-(4-benzyloxyphenyl)ethanol, a diester of glutaric acid and 2-[4-(4-chlorobenzyloxy)phenyl]ethanol, a diester of adipic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of pimelic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of suberic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of suberic acid and 2-[4-(3-methylbenzyloxy)phenyl]ethanol, and a diester of malonic acid and 2-[4-(4-chlorobenzyloxy)phenyl]ethanol. Examples of such esters include a diester of 2-(4-benzyloxyphenyl)ethanol with suberic acid, a diester of 2-(4-(2,4-dichlorobenzyloxy)phenyl)ethanol with suberic acid, a diester of 2-(4-benzyloxyphenyl)ethanol with suberic acid, a diester of 2-(4-benzyloxyphenyl)ethanol with azelaic acid, a diester of 2-(4-benzyloxyphenyl)ethanol with sebacic acid, a diester of 1,10-decanedicarboxylic acid and 2-(4-benzyloxyphenyl)ethanol with 1,18-octadecanedicarboxylic acid, and a diester of 1,18-octadecanedicarboxylic acid and 2-(4-benzyloxyphenyl)ethanol with 2-[4-(2-methylbenzyloxy)phenyl)]ethanol.

[0027] Furthermore, a compound represented by the following general formula (5) can also be used as the component (iii). [ka] (In the formula, R represents an alkyl group or alkenyl group having 1 to 21 carbon atoms, and n represents an integer of 1 to 3.) Examples of the compound include a diester of 1,3-bis(2-hydroxyethoxy)benzene and capric acid, a diester of 1,3-bis(2-hydroxyethoxy)benzene and undecanoic acid, a diester of 1,3-bis(2-hydroxyethoxy)benzene and lauric acid, a diester of 1,3-bis(2-hydroxyethoxy)benzene and myristic acid, a diester of 1,4-bis(hydroxymethoxy)benzene and butyric acid, a diester of 1,4-bis(hydroxymethoxy)benzene and isovaleric acid, a diester of 1,4-bis(2-hydroxyethoxy)benzene and acetic acid, and a diester of 1,4-bis(hydroxymethoxy)benzene and acetic acid. Examples include a diester of 4-bis(2-hydroxyethoxy)benzene and propionic acid, a diester of 1,4-bis(2-hydroxyethoxy)benzene and valeric acid, a diester of 1,4-bis(2-hydroxyethoxy)benzene and caproic acid, a diester of 1,4-bis(2-hydroxyethoxy)benzene and caprylic acid, a diester of 1,4-bis(2-hydroxyethoxy)benzene and capric acid, a diester of 1,4-bis(2-hydroxyethoxy)benzene and lauric acid, and a diester of 1,4-bis(2-hydroxyethoxy)benzene and myristic acid.

[0028] Furthermore, as the component (iii), a compound represented by the following general formula (6) can also be used. [ka] (In the formula, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, m represents an integer of 1 to 3, and n represents an integer of 1 to 20.) Examples of the compound include a diester of succinic acid and 2-phenoxyethanol, a diester of suberic acid and 2-phenoxyethanol, a diester of sebacic acid and 2-phenoxyethanol, a diester of 1,10-decanedicarboxylic acid and 2-phenoxyethanol, and a diester of 1,18-octadecanedicarboxylic acid and 2-phenoxyethanol.

[0029] Furthermore, a compound represented by the following general formula (7) can also be used as the component (iii). [ka] (In the formula, R represents any one of an alkyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, a cycloalkyl group, and an alkenyl group having 4 to 22 carbon atoms; X represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom; and n represents 0 or 1.) Examples of the compound include decyl 4-phenylbenzoate, lauryl 4-phenylbenzoate, myristyl 4-phenylbenzoate, cyclohexylethyl 4-phenylbenzoate, octyl 4-biphenylacetate, nonyl 4-biphenylacetate, decyl 4-biphenylacetate, lauryl 4-biphenylacetate, myristyl 4-biphenylacetate, tridecyl 4-biphenylacetate, pentadecyl 4-biphenylacetate, cetyl 4-biphenylacetate, cyclopentyl 4-biphenylacetate, cyclohexylmethyl 4-biphenylacetate, hexyl 4-biphenylacetate, and cyclohexylmethyl 4-biphenylacetate.

[0030] Furthermore, as the component (iii), a compound represented by the following general formula (8) can also be used. [ka] (In the formula, R represents any one of an alkyl group having 3 to 18 carbon atoms and an aliphatic acyl group having 3 to 18 carbon atoms; X represents any one of a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, and a halogen atom; Y represents any one of a hydrogen atom and a methyl group; and Z represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, and a halogen atom.) Examples of the compound include phenoxyethyl 4-butoxybenzoate, phenoxyethyl 4-pentyloxybenzoate, phenoxyethyl 4-tetradecyloxybenzoate, an ester of phenoxyethyl 4-hydroxybenzoate with dodecanoic acid, and dodecyl ether of phenoxyethyl vanillate.

[0031] Furthermore, as the component (iii), a compound represented by the following general formula (9) can also be used. [ka] (In the formula, R represents any one of an alkyl group having 4 to 22 carbon atoms, an alkenyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, and a cycloalkyl group; X represents any one of a hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom; Y represents any one of a hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom; and n represents 0 or 1.) Examples of the compound include the benzoate ester of octyl p-hydroxybenzoate, the benzoate ester of decyl p-hydroxybenzoate, the p-methoxybenzoate ester of heptyl p-hydroxybenzoate, the o-methoxybenzoate ester of dodecyl p-hydroxybenzoate, and the benzoate ester of cyclohexylmethyl p-hydroxybenzoate.

[0032] Furthermore, as the component (iii), a compound represented by the following general formula (10) can also be used. [ka] (In the formula, R represents any one of an alkyl group having 3 to 18 carbon atoms, a cycloalkylalkyl group having 6 to 11 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, and an alkenyl group having 3 to 18 carbon atoms; X represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a halogen atom; and Y represents any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, and a halogen atom.) Examples of the compound include phenoxyethyl ether of nonyl p-hydroxybenzoate, phenoxyethyl ether of decyl p-hydroxybenzoate, phenoxyethyl ether of undecyl p-hydroxybenzoate, and phenoxyethyl ether of dodecyl vanillate.

[0033] Furthermore, as the component (iii), a compound represented by the following general formula (11) can also be used. [ka] (In the formula, R represents a cycloalkyl group having 3 to 8 carbon atoms or a cycloalkylalkyl group having 4 to 9 carbon atoms, and n represents an integer of 1 to 3.) Examples of the compound include a diester of 1,3-bis(2-hydroxyethoxy)benzene and cyclohexanecarboxylic acid, a diester of 1,4-bis(2-hydroxyethoxy)benzene and cyclohexanepropionic acid, and a diester of 1,3-bis(2-hydroxyethoxy)benzene and cyclohexanepropionic acid.

[0034] Furthermore, as the component (iii), a compound represented by the following general formula (12) can also be used. [ka] (In the formula, R represents an alkyl group having 3 to 17 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, or a cycloalkylalkyl group having 5 to 8 carbon atoms; X represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a methoxy group, an ethoxy group, or a halogen atom; and n represents an integer of 1 to 3.) Examples of the compound include a diester of 4-phenylphenol ethylene glycol ether and cyclohexane carboxylic acid, a diester of 4-phenylphenol diethylene glycol ether and lauric acid, a diester of 4-phenylphenol triethylene glycol ether and cyclohexane carboxylic acid, a diester of 4-phenylphenol ethylene glycol ether and octanoic acid, a diester of 4-phenylphenol ethylene glycol ether and nonanoic acid, a diester of 4-phenylphenol ethylene glycol ether and decanoic acid, and a diester of 4-phenylphenol ethylene glycol ether and myristic acid.

[0035] Furthermore, reversible thermochromic compositions of the heat-coloring type (which develops color when heated and loses color when cooled) that use specific alkoxyphenol compounds having a straight-chain or side-chain alkyl group having 3 to 18 carbon atoms as the electron-accepting compound (JP Patent Publication Nos. 11-129623 and 11-5973), specific hydroxybenzoic acid esters (JP Patent Publication No. 2001-105732), or gallic acid esters (JP Patent Publication Nos. 51-44706 and 2003-253149) can also be applied (see FIG. 3).

[0036] The ratio of each component of the reversible thermochromic composition depends on the concentration, color change temperature, color change form, and type of each component, but generally, the component ratio that gives the desired properties is in the range of 1 part of component (a) to 0.1 to 100, preferably 0.1 to 50, and more preferably 0.5 to 20, of component (b) and 1 to 800, preferably 5 to 200, and more preferably 10 to 100, of component (c) (all the above ratios are parts by mass).

[0037] Furthermore, various light stabilizers can be added as necessary. The light stabilizer is contained in order to prevent photodegradation of the reversible thermochromic composition consisting of components (a), (b) and (c), and is contained in a ratio of 0.3 to 24 mass%, preferably 0.3 to 16 mass%, per 1 mass% of component (a). Among the light stabilizers, the ultraviolet absorber effectively blocks ultraviolet rays contained in sunlight and the like, and prevents photodegradation caused by the excited state due to the photoreaction of component (a). The antioxidant, singlet oxygen quencher, superoxide anion quencher, ozone quencher and the like suppress oxidation reactions caused by light. The light stabilizers may be used alone or in combination of two or more kinds.

[0038] The reversible thermochromic composition can be used as a reversible thermochromic microencapsulated pigment by being encapsulated in a microcapsule. Microencapsulation may be carried out by any of the known methods, such as interfacial polymerization, in situ polymerization, liquid curing coating, phase separation from an aqueous solution, phase separation from an organic solvent, melt dispersion cooling, air suspension coating, spray drying, etc., and may be appropriately selected depending on the application. Furthermore, a secondary resin film may be provided on the surface of the microcapsule depending on the purpose to impart durability or modify the surface properties for practical use. The microcapsule pigment preferably has a mass ratio of inclusions / wall film of 7 / 1 to 1 / 1. By having the wall film ratio within this range, it is possible to prevent a decrease in color density and vividness during color development, and more preferably, the mass ratio of inclusions / wall film is 6 / 1 to 1 / 1. By encapsulating the pigment in the microcapsules, a chemically and physically stable pigment can be obtained.

[0039] By blending a non-thermochromic colorant into the reversible thermochromic microencapsulated pigment, it is possible to make the pigment into one that exhibits alternation from color (1) to a different color (2) due to a change in temperature.

[0040] The reversible thermochromic microencapsulated pigment satisfies practical application when its particle size is in the range of 0.5 to 30 μm, preferably 1.0 to 20 μm, and more preferably 1.0 to 10 μm. The particle size and average particle size were measured by determining the particle area using Mountec's image analysis particle size distribution measurement software "Mac View", calculating the projected area circle equivalent diameter (Heywood diameter) from the area of ​​the particle area, and measuring the particle size and average particle size of the particles equivalent to an equal volume sphere using this value. In addition, if the particle size of all particles or the majority of particles exceeds 0.2 μm, it is also possible to measure the particle size and average particle size of the particles equivalent to an equal volume sphere by the Coulter method using a particle size distribution measurement device (Beckman Coulter, Inc., product name: Multisizer 4e). Furthermore, the volumetric particle size and average particle size (median size) may be measured using a laser diffraction / scattering particle size distribution analyzer (device name: LA-960V2, manufactured by HORIBA, Ltd.) calibrated based on values ​​measured using a measuring device based on the Coulter method.

[0041] The reversible thermochromic material can be dispersed in a vehicle containing water and / or an organic solvent and, if necessary, various additives, to prepare a printing ink or inkjet ink for use in screen printing, offset printing, process printing, gravure printing, etc., and then printed on a support to form a reversible thermochromic pattern. By incorporating a non-thermochromic colorant into the ink, it is possible to make the ink capable of changing from color (1) to a different color (2) due to a change in temperature.

[0042] The non-color-changing design contains a non-color-changing colorant and is a design selected from letters, symbols, and pictures, and is related to the reversible thermochromic design. The designs include designs of people, animals, plants, fruits, food products, vehicles, buildings, celestial bodies, patterns, and the like. The non-discoloring colorant may be a general dye or pigment, and the dye may be an acid dye, a basic dye, or a direct dye. Examples of the pigment that can be used include inorganic pigments such as carbon black and ultramarine, organic pigments such as azo pigments, phthalocyanine pigments, indigo pigments, thioindigo pigments, threne pigments, quinacridone pigments, anthraquinone pigments, threne pigments, diketopyrrolopyrrole pigments, dioxazine pigments, perylene pigments, perinone pigments, and isoindolinone pigments, and fluorescent pigments. The non-discoloring colorant can be dispersed in a vehicle containing water and / or an organic solvent and, if necessary, various additives to prepare a printing ink or inkjet ink for use in screen printing, offset printing, process printing, gravure printing, etc., and then printed to form a non-discoloring pattern on a support.

[0043] When the reversible thermochromic material in the reversible thermochromic pattern is a reversible thermochromic resin particle containing a reversible thermochromic composition that changes from colored to colorless and is composed of at least (a) an electron-donating organic color-forming compound, (b) an electron-accepting compound, and (c) a reaction medium that controls the color reactions of (a) and (b), or a reversible thermochromic microcapsule pigment that encapsulates a reversible thermochromic composition that changes from colored to colorless and is composed of at least (a) an electron-donating organic color-forming compound, (b) an electron-accepting compound, and (c) a reaction medium that controls the color reactions of (a) and (b), the reversible thermochromic resin particle or the reversible thermochromic microcapsule pigment has a relatively large particle diameter, so the pattern tends to be thick. Therefore, in order to thicken the non-color-changing pattern, it is possible to overprint ink containing a non-color-changing colorant, but it is preferable to make the thickness of the patterns approximately the same by adding reversible thermochromic resin particles, or resin particles or microcapsule pigments having approximately the same particle diameter as the reversible thermochromic microcapsule pigment, to the ink to form the non-color-changing pattern. Furthermore, by using microcapsule pigments with the same wall film (capsule coating) for the microcapsule pigments contained in the reversible thermochromic pattern and the non-color-changing pattern, the surface conditions of the patterns can be made similar to each other, making it difficult to distinguish between the patterns, which is advantageous.

[0044] Examples of the resin constituting the resin particles include polystyrene, acrylic resin, epoxy resin, melamine resin, polyester, polyvinyl chloride, polybutadiene, benzoguanamine resin, polyamide, urethane resin, polymethyl methacrylate, acrylic-urethane copolymer resin, phenol resin, polyethylene, polypropylene, polyacrylonitrile, polyacetal, ethylene-propylene copolymer resin, ethylene-vinyl acetate copolymer resin, styrene-acrylic copolymer resin, styrene-butadiene copolymer resin, styrene-acrylonitrile copolymer resin, and acrylonitrile-butadiene copolymer resin. The resin particles may be resin particles in which a non-discoloring colorant is uniformly dispersed, or resin particles whose surfaces are coated with a non-discoloring colorant. The interior of the microcapsule pigment may be hollow, or may contain component (c) of a reversible thermochromic composition comprising at least a conventionally known (a) electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium for controlling the color-forming reaction of (a) and (b). Examples of the component (iii) include alcohols, esters, ketones, ethers, and acid amides. One example is a microcapsule pigment that changes color from white to colorless and encapsulates a compound selected from crystalline alcohols, esters, ethers, and ketones having a melting point in the range of -40°C to +95°C. The microcapsule pigment may be a microcapsule pigment encapsulating a non-discoloring colorant, or a microcapsule pigment containing a non-discoloring colorant in the microcapsule wall membrane, or the surface of the microcapsule pigment may be coated with a non-discoloring colorant for use.

[0045] The thickness of the reversible thermochromic pattern and the non-chromic pattern formed on the support is approximately the same, making it difficult to distinguish them by visual inspection or touch, and the user cannot predict which pattern will change color, allowing the enjoyment of the color change to be enjoyed. The thickness (D1) of the reversible thermochromic pattern is 2 to 100 μm, preferably 5 to 50 μm, and more preferably 10 to 50 μm, and the thickness (D2) of the non-chromic pattern satisfies the following formula (1), so that the difference in thickness between the patterns becomes difficult to distinguish. 0.7≦D2 / D1≦1.3 (1) The formula (1) preferably satisfies 0.8≦D2 / D1≦1.2, and more preferably satisfies 0.9≦D2 / D1≦1.1. The thickness of the pattern can be measured by measuring the cross section of the pattern using a microscope (Microscope VHX-6000, manufactured by Keyence Corporation).

[0046] In order to make the thickness of the reversible thermochromic pattern and the non-color-changing pattern approximately the same, it is easier to satisfy productivity if the average particle diameter of the reversible thermochromic microcapsule pigment contained in the first pattern and the average particle diameter of the resin particles or microcapsule pigment contained in the second pattern are approximately the same. When the average particle diameter (L1) of the reversible thermochromic microcapsule pigment contained in the reversible thermochromic pattern and the average particle diameter (L2) of the resin particles or microcapsule pigment contained in the non-color-changing pattern satisfy formula (2), the thickness tends to be approximately the same. 0.7≦L2 / L1≦1.3 (2) The formula (2) preferably satisfies 0.8≦L2 / L1≦1.2, and more preferably satisfies 0.9≦L2 / L1≦1.1.

[0047] The reversible thermochromic pattern and the non-color-changing pattern are patterns related to each other, and examples of such patterns include educational and intellectual development applications in which a reversible thermochromic pattern consisting of a plurality of characters of similar colors, a non-color-changing pattern consisting of a plurality of characters of similar colors, and a non-color-changing pattern that is equal to a meaningful word when the reversible thermochromic pattern changes color; educational and intellectual development applications in which a non-color-changing pattern consisting of a document explaining the reversible thermochromic pattern is formed, with one of a plurality of different patterns of similar colors being a reversible thermochromic pattern and the others being non-color-changing patterns; puzzle-solving applications in which a reversible thermochromic pattern consisting of a plurality of characters of similar colors and a non-color-changing pattern consisting of a plurality of characters are randomly formed, and only the reversible thermochromic pattern is changed color to allow the meaningful word to be recognized; and anti-counterfeiting applications in which one of a plurality of identical symbols of similar colors is a reversible thermochromic pattern, and the other symbols are non-color-changing patterns.

[0048] Since the color of the reversible thermochromic pattern when the reversible thermochromic material contained in the reversible thermochromic pattern is in a colored state and the color of the non-color-changing pattern are the same color or similar colors, it becomes difficult to distinguish between the patterns, making the device suitable for applications in which correct or incorrect answers are selected alternatively. Note that similar colors refer to the color closest to the color in question and the hue adjacent to both sides of that color on the Munsell 40 hue wheel (the numbers expressed in JIS Z 8721 (1993) 3.1 "Method of expressing hue" are within ±2.5, i.e., a range of 5.0). In addition, when the reversible thermochromic design changes color from a color (1) to a different color (2) because the color of the reversible thermochromic design in the decolorized state of the reversible thermochromic material contained in the reversible thermochromic design is the same color or a similar color as the color of the non-color-changing design, it can be difficult to distinguish between the designs, and therefore the design can be used for selecting correct or incorrect answers in an alternative manner.

[0049] In the case where the reversible thermochromic microencapsulated pigment exhibits hysteresis characteristics with respect to the color concentration-temperature curve, and exhibits alternation between a colored state and a colorless state, and in the process of increasing temperature from a colored state, the pigment begins to lose color when it reaches temperature t3 and becomes completely colorless in a temperature range of t4 or higher, which is higher than temperature t3, and in the process of decreasing temperature from the colorless state, the pigment begins to become colored when it reaches temperature T2, which is lower than temperature T3, and becomes completely colored in a temperature range of t1 or lower, which is lower than temperature t2, by setting temperature t4 in the range of 30 to 90°C, preferably 30 to 80°C, and more preferably 30 to 70°C, the color changes due to body heat when touched with the hand, or due to frictional heat caused by rubbing with a finger or using a friction body, thereby enabling easy color change.

[0050] A transparent metallic gloss layer can be provided on the reversible thermochromic pattern and the non-chromic pattern, making the minute thickness difference between the first and second patterns less noticeable and also making the color difference between the patterns less noticeable. Examples of the transparent metallic luster pigment contained in the transparent metallic luster layer include pigments having a core material such as natural mica, synthetic mica, glass pieces, alumina, and transparent film pieces whose surface is coated with a metal oxide such as titanium oxide. In addition, a transparent resin layer can be provided on the reversible thermochromic design and the non-chromic design, making the minute difference in thickness between the first design and the second design less noticeable. By having the outer surface of the transparent resin layer be matte, the difference in color between the patterns can be made less noticeable. The transparent resin layer may contain light stabilizers such as ultraviolet absorbers, antioxidants, singlet oxygen quenchers, superoxide anion quenchers, and ozone quenchers.

[0051] The reversible thermochromic pattern can be changed in color by touch, rubbing with fingers, or application of a friction body, a heat-color changing tool, or a cold-heat-color changing tool. The heating device may be an electrically heated discoloration device equipped with a resistance heating element or a heat discoloration device filled with hot water or the like, and the cooling device may be an electrically heated discoloration device using a Peltier element or a cold-heat discoloration device filled with a refrigerant such as cold water or ice chips, but it is preferable to use a friction body that can be discolored in a simple manner. The friction body is preferably an elastic body such as an elastomer or plastic foam, which has a high elastic feel and can generate appropriate friction and generate frictional heat when rubbed, but it may also be a plastic molded body, stone, wood, metal, or fabric. Although it is possible to use an eraser for friction, it is preferable to use a friction body such as that described above, since the friction generates eraser dust. Examples of the material of the friction body include silicone resin, SBS resin (styrene-butadiene-styrene copolymer), and SEBS resin (styrene-ethylene-butylene-styrene block copolymer). By combining the reversible thermochromic printed material with a friction body, a reversible thermochromic printed material set having excellent portability can be obtained. Furthermore, by combining the reversible thermochromic printed matter with a writing instrument equipped with a friction member, a reversible thermochromic printed matter set can be obtained that is highly portable and also allows the user to write on the printed matter, improving convenience. The location where the friction member is fixed can be the tip (top) of the cap, or the tip (part where no writing tip is provided) of the barrel, or the like. The ink contained in the writing instrument may be a non-thermochromic ink, but by using ink that can be erased by heating, it is possible to make the writing instrument more convenient by allowing repeated writing. The colorant contained in the heat-decolorizable ink can be the thermochromic material described above. The writing implement may be a solid writing implement such as a pencil or a crayon. EXAMPLES

[0052] Examples are shown below, but the present invention is not limited to these examples. In the examples, "parts" refers to parts by weight. Example 1 (see FIG. 4) Preparation of reversible thermochromic prints A synthetic paper substrate 2 was coated with 50.0 parts of 4-benzyloxyphenylethyl caprate encapsulating a reversible thermochromic composition having color memory, the composition consisting of (a) 4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluoran as a component, (b) 4.5 parts of 4,4'-(2-methylpropylidene)bisphenol and 7.5 parts of 2,2-bis(4'-hydroxyphenyl)hexafluoropropane as a component, and (c) 50.0 parts of 4-benzyloxyphenylethyl caprate. The characters "tsu", "ku", and "e" were randomly printed using a reversible thermochromic screen printing ink consisting of 30 parts of a microcapsule pigment with color memory (t1: -20°C, t2: -9°C, t3: 40°C, t4: 57°C, ΔH: 63°C, average particle size: 2.0 μm, color change from black to colorless), 5 parts of blue pigment, 50 parts of an acrylic resin emulsion (solid content 45%), 1 part of viscosity modifier, 0.2 parts of defoamer, and 13.8 parts of water, and then dried to form a reversible thermochromic pattern 3. Next, black pigment Using a black screen printing ink consisting of 5 parts of acrylic resin emulsion (solid content 45%), 50 parts of acrylic resin emulsion (solid content 45%), 1 part of viscosity modifier, 0.2 parts of defoaming agent, and 43.8 parts of water, characters other than "tsu", "ku", and "e" were randomly printed and dried, and the black screen printing ink was repeatedly used to overprint the characters other than "tsu", "ku", and "e" a total of three times to form a non-color-changing pattern 4, thereby obtaining a reversible thermochromic printed matter 1. The thickness of the reversible thermochromic pattern was 30 μm, and the thickness of the non-thermochromic pattern was 25 μm.

[0053] The reversible thermochromic design and the non-color-changing design of the reversible thermochromic printed matter were black and could not be distinguished by visual inspection, and even when the thicknesses of the designs were compared, they could not be distinguished by visual inspection or touch. When the reversible thermochromic printed material was rubbed with a friction material made of SEBS resin, only the characters "tsu," "ku," and "e" turned blue, allowing the character "tsukue" to be understood, and therefore the material could be used as a teaching tool. Furthermore, the reversible thermochromic pattern that had turned blue turned black when cooled to below -20°C, satisfying the practicality of repeated use.

[0054] Example 2 Preparation of a set of reversible thermochromic printed materials The reversible thermochromic printed matter obtained in Example 1 was combined with a friction body made of SEBS resin to obtain a reversible thermochromic printed matter set. As in Example 1, when the reversible thermochromic printed material set was rubbed with a friction body, only the characters "tsu," "ku," and "e" turned blue, allowing the character "tsukue" to be understood, and therefore the set could be used as a teaching tool. Furthermore, the reversible thermochromic pattern that had turned blue turned black when cooled to below -20°C, satisfying the practicality of repeated use.

[0055] Example 3 (see FIG. 4) Preparation of reversible thermochromic prints A reversible thermochromic composition having color memory properties, the composition consisting of (a) 4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluoran as a component, (b) 4.5 parts of 4,4'-(2-methylpropylidene)bisphenol and 7.5 parts of 2,2-bis(4'-hydroxyphenyl)hexafluoropropane as a component, and (c) 50.0 parts of 4-benzyloxyphenylethyl caprate as a component, was encapsulated on synthetic paper as a support 2. The characters "tsu," "ku," and "e" were randomly printed using a reversible thermochromic screen printing ink consisting of 30 parts of microcapsule pigment (t1: -20°C, t2: -9°C, t3: 40°C, t4: 57°C, ΔH: 63°C, average particle size: 2.0 μm, color change from black to colorless), 5 parts of blue pigment, 50 parts of acrylic resin emulsion (solid content 45%), 1 part of viscosity modifier, 0.2 parts of defoamer, and 13.8 parts of water, and then dried to form reversible thermochromic pattern 3. Next, using a black screen printing ink consisting of 30 parts of microcapsule pigment (average particle size: 2.0 μm, changes color from white to colorless) encapsulating 66.5 parts of 4-benzyloxyphenylethyl caprate, 5 parts of black pigment, 1 part of viscosity modifier, 0.2 parts of defoamer, and 63.8 parts of water, characters other than "tsu," "ku," and "e" were randomly printed and dried to form a non-color-changing pattern 4, thereby obtaining a reversible thermochromic printed matter 1. The thickness of the reversible thermochromic pattern was 30 μm, and the thickness of the non-thermochromic pattern was 28 μm.

[0056] The reversible thermochromic design and the non-color-changing design of the reversible thermochromic printed matter were black and could not be distinguished by visual inspection, and even when the thicknesses of the designs were compared, they could not be distinguished by visual inspection or touch. When the reversible thermochromic printed material was rubbed with a friction body, only the characters "tsu," "ku," and "e" turned blue, allowing the child to understand the character "tsukue," and therefore the material could be used as a teaching tool. Furthermore, the reversible thermochromic pattern that had turned blue turned black when cooled to below -20°C, satisfying the practicality of repeated use.

[0057] Example 4 Preparation of a set of reversible thermochromic printed materials A reversible thermochromic printed matter set was obtained by combining the reversible thermochromic printed matter obtained in Example 3 with a writing instrument containing ink that can be erased by heating and equipped with a friction member at the rear of the barrel. As in Example 3, when the reversible thermochromic printed material set was rubbed with the friction body of a writing implement, only the characters "tsu," "ku," and "e" turned blue, allowing the character "tsukue" to be understood, and therefore the set could be used as a teaching tool. Furthermore, the reversible thermochromic pattern that had turned blue turned black when cooled to below -20°C, satisfying the practicality of repeated use. Furthermore, the writing implement could also be used to draw a picture of a desk on the printed matter.

[0058] Example 5 Preparation of reversible thermochromic prints A picture of a banana was printed on a synthetic paper substrate using a reversible thermochromic offset ink containing 30 parts of a reversible thermochromic microcapsule pigment (t1: 19°C, t2: 26°C, t3: 31°C, t4: 38°C, ΔH: 12°C, average particle size: 1.5μm, color change from black to colorless) encapsulating a reversible thermochromic composition consisting of 1.0 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluoran as component (A), 8.0 parts of 1,1-bis(4-hydroxyphenyl)n-decane as component (B), and 50.0 parts of n-nonyl stearate as component (C), 5 parts of a yellow pigment, and 65.0 parts of a linseed oil-based offset ink vehicle. The ink was then dried to form a reversible thermochromic pattern. Next, a picture of an apple and the words "Which one will turn yellow?" were printed using a black offset ink made by mixing 30 parts of a microencapsulated pigment (average particle size: 1.7 μm, changes color from white to colorless) encapsulating 50.0 parts of n-nonyl stearate, 5 parts of a black pigment, and 65.0 parts of a linseed oil-based offset ink vehicle, and then dried to form a non-color-changing pattern, resulting in a reversible thermochromic print. The thickness of the reversible thermochromic pattern was 5 μm, and the thickness of the non-thermochromic pattern was 5.5 μm.

[0059] The reversible thermochromic design and the non-color-changing design of the reversible thermochromic printed matter were black and could not be distinguished by visual inspection, and even when the thicknesses of the designs were compared, they could not be distinguished by visual inspection or touch. When the reversible thermochromic printed matter was rubbed with a finger, only the banana picture turned yellow, so that it could be used as an educational tool (for solving puzzles). The reversible thermochromic pattern which had turned yellow turned black when cooled to below 19° C., satisfying the practicality of repeated use.

[0060] Example 6 Preparation of a set of reversible thermochromic printed materials The reversible thermochromic printed matter obtained in Example 5 was combined with a friction body made of SEBS resin to obtain a reversible thermochromic printed matter set. The reversible thermochromic printed material set could be used as an educational tool (for solving puzzles) because when the reversible thermochromic printed material was rubbed with a friction body, only the banana picture turned yellow. The reversible thermochromic pattern which had turned yellow turned black when cooled to below 19° C., satisfying the practicality of repeated use.

[0061] Example 7 Preparation of reversible thermochromic prints On a synthetic paper as a support, 1.0 part of 2-(dibutylamino)-8-(dipentylamino)-4-methyl-spiro[5H-[1]benzopyrano[2,3-g]pyrimidine-5,1'(3'H)-isobenzofuran]-3-one as component (A), 8.0 parts of hexadecyl 4-hydroxybenzoate as component (B), 20.0 parts of hexadecane as component (C), 5.0 parts of low molecular weight polystyrene resin (softening point 75°C) as component (D), and 1, A picture of grapes was printed using a reversible thermochromic offset ink containing 30 parts of a reversible thermochromic microcapsule pigment (T1: 10°C, T2: 17°C, T3: 32°C, T4: 44°C, ΔH: 24.5°C, average particle size: 1.5 μm, color change from colorless to pink) encapsulating a reversible thermochromic composition consisting of 1.0 part of 4-didecyloxybenzene, 5 parts of a blue pigment, and 65.0 parts of a linseed oil-based offset ink vehicle, and then dried to form a reversible thermochromic pattern. Next, a picture of an apple and the words "Which one will turn purple?" were printed using a blue offset ink made by mixing 30 parts of hollow microcapsule pigment (average particle size: 1.7 μm), 5 parts of blue pigment, and 65.0 parts of linseed oil-based offset ink vehicle, and then dried to form a non-color-changing pattern, resulting in a reversible thermochromic print. The thickness of the reversible thermochromic pattern was 5 μm, and the thickness of the non-thermochromic pattern was 5.8 μm.

[0062] The reversibly thermochromic design and the non-color-changing design of the reversibly thermochromic printed matter were blue in color and could not be distinguished by visual inspection, and even when the thicknesses of the designs were compared, they could not be distinguished by visual inspection or touch. When the reversible thermochromic printed matter was rubbed with a friction material made of SEBS resin, only the grape pattern changed color to purple, making it possible to use the matter as a teaching tool. Furthermore, the reversible thermochromic pattern that had turned purple turned blue when cooled to below 10°C, satisfying the practicality of repeated use.

[0063] Example 8 Preparation of a set of reversible thermochromic printed materials The reversible thermochromic printed matter obtained in Example 7 was combined with a friction body made of SEBS resin to obtain a reversible thermochromic printed matter set. The reversible thermochromic printed material set could be used as a teaching tool because when the reversible thermochromic printed material was rubbed with a friction body, only the grape pattern changed color to purple. Furthermore, the reversible thermochromic pattern that had turned purple turned blue when cooled to below 10°C, satisfying the practicality of repeated use.

[0064] Example 9 Preparation of reversible thermochromic prints A reversible thermochromic composition having color memory properties, the composition comprising: (a) 4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluoran as a support; (b) 4.5 parts of 4,4'-(2-methylpropylidene)bisphenol and 7.5 parts of 2,2-bis(4'-hydroxyphenyl)hexafluoropropane as components; and (c) 50.0 parts of 4-benzyloxyphenylethyl caprate as a component, and containing the reversible thermochromic composition on a synthetic paper support. A reversible thermochromic screen printing ink consisting of 30 parts of microcapsule pigment (t1: -20°C, t2: -9°C, t3: 40°C, t4: 57°C, ΔH: 63°C, average particle size: 2.0 μm, color change from black to colorless), 5 parts of red pigment, 50 parts of acrylic resin emulsion (solid content 45%), 1 part of viscosity modifier, 0.2 parts of defoamer, and 13.8 parts of water was used to print only the letter "E" out of the letters "REAL", and then dried to form a reversible thermochromic pattern. Next, the letters "R AL" out of the letters "REAL" were printed using a black screen printing ink consisting of 30 parts of a microcapsule pigment (average particle size: 2.0 μm, changes color from white to colorless) encapsulating 50.0 parts of 4-benzyloxyphenylethyl caprate, 5 parts of a black pigment, 50 parts of an acrylic resin emulsion (solid content 45%), 1 part of a viscosity modifier, 0.2 parts of an antifoaming agent, and 13.8 parts of water, and then dried to form a non-color-changing pattern, thereby obtaining a reversible thermochromic print. The thickness of the reversible thermochromic pattern was 30 μm, and the thickness of the non-thermochromic pattern was 26 μm.

[0065] The reversible thermochromic design and the non-color-changing design of the reversible thermochromic printed matter were black and could not be distinguished by visual inspection, and even when the thicknesses of the designs were compared, they could not be distinguished by visual inspection or touch. When the reversible thermochromic printed material was rubbed with a friction body, only the letter "E" turned red, making it possible to use it to prevent counterfeiting. The reversible thermochromic pattern, which had turned red, turned black when cooled to below -20°C, satisfying the practicality of repeated use.

[0066] Example 10 (see FIG. 5) Preparation of reversible thermochromic prints A reversible thermochromic matrix having a color memory property and containing a reversible thermochromic composition having a color memory property, the reversible thermochromic composition comprising (a) 4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluoran as a component, (b) 4.5 parts of 4,4'-(2-methylpropylidene)bisphenol and 7.5 parts of 2,2-bis(4'-hydroxyphenyl)hexafluoropropane as a component, and (c) 50.0 parts of 4-benzyloxyphenylethyl caprate as a component, was placed on a synthetic paper as a support 2. The characters "tsu," "ku," and "e" were randomly printed using a reversible thermochromic screen printing ink consisting of 30 parts of microcapsule pigment (t1: -20°C, t2: -9°C, t3: 40°C, t4: 57°C, ΔH: 63°C, average particle size: 2.0 μm, color change from black to colorless), 5 parts of pink pigment, 50 parts of acrylic resin emulsion (solid content 45%), 1 part of viscosity modifier, 0.2 parts of defoamer, and 13.8 parts of water, and then dried to form reversible thermochromic pattern 3. Next, characters other than "tsu," "ku," and "e" were randomly printed and dried using a black screen printing ink consisting of 30 parts of a microcapsule pigment (average particle size: 2.0 μm, changes color from white to colorless) encapsulating 50.0 parts of 4-benzyloxyphenylethyl caprate, 5 parts of black pigment, 1 part of viscosity modifier, 0.2 parts of defoamer, and 63.8 parts of water, to form non-discoloring pattern 4. The thickness of the reversible thermochromic pattern was 30 μm, and the thickness of the non-thermochromic pattern was 28 μm. Next, the reversible thermochromic pattern and the non-color-changing pattern were printed using an ink containing a transparent metallic luster pigment (Iriodin 205) and dried to form a transparent metallic luster layer 5, thereby obtaining a reversible thermochromic printed matter 1.

[0067] The reversibly thermochromic design and the non-thermochromic design of the reversibly thermochromic printed matter were gold in color and could not be distinguished by visual inspection, and even when the thicknesses of the designs were compared, they could not be distinguished by visual inspection or touch. When the reversible thermochromic printed material was rubbed with a friction body, only the characters "tsu," "ku," and "e" changed color to pink, allowing the child to understand the character "tsukue," and therefore the material could be used as a teaching tool. Furthermore, the reversible thermochromic pattern that had turned pink turned gold when cooled to below -20°C, satisfying the practicality of repeated use.

[0068] Example 11 Preparation of a set of reversible thermochromic printed materials The reversible thermochromic printed matter obtained in Example 10 was combined with a writing instrument containing ink that can be erased by heating and equipped with a friction member at the rear of the barrel to obtain a reversible thermochromic printed matter set. As in Example 10, when the reversible thermochromic printed material set was rubbed with the friction body of a writing instrument, only the characters "tsu," "ku," and "e" turned pink, allowing the character "tsukue" to be understood, and therefore the set could be used as a teaching tool. Furthermore, the reversible thermochromic pattern that had turned pink turned gold when cooled to below -20°C, satisfying the practicality of repeated use. Furthermore, the writing implement could also be used to form a picture of a desk on a printed matter. [Explanation of symbols]

[0069] t1 Complete color development temperature of heat-discolorable reversible thermochromic composition t2 Color development start temperature of heat-discolorable reversible thermochromic composition t3: The starting temperature of discoloration of reversible thermochromic composition that discolors when heated t4 Complete decolorization temperature of heat-decolorizing type reversible thermochromic composition T1 Complete decolorization temperature of heat-coloring type reversible thermochromic composition T2: The starting temperature of discoloration of a reversible thermochromic composition that develops color by heating T3: Color development start temperature of heat-coloring type reversible thermochromic composition T4 Complete color development temperature of heat-coloring type reversible thermochromic composition ΔH Hysteresis width 1. Reversible thermochromic prints 2 Support 3. Reversible thermochromic patterns 4. Non-discoloring patterns

Claims

1. The reversible thermochromic printed matter is characterized in that it comprises, on the surface of a support, a reversible thermochromic design containing a reversible thermochromic material and selected from letters, symbols and designs, and a non-color-changing design containing a non-color-changing colorant and selected from letters, symbols and designs related to the reversible thermochromic design, and the thickness of the reversible thermochromic design and the non-color-changing design are substantially the same.

2. The thickness of the reversible thermochromic pattern (D １ ) is 2 to 100 μm, and the thickness of the non-discoloring pattern (D ２ 2. The reversible thermochromic printed matter according to claim 1, wherein ##STR1## satisfies the following formula (1): 0.7≦D ２ / D １ ≦1.3 (1)

3. 2. The reversible thermochromic printed matter according to claim 1, wherein the reversible thermochromic material in the reversible thermochromic pattern is a reversible thermochromic microcapsule pigment encapsulating a reversible thermochromic composition that changes color from colored to colorless and is composed of at least (i) an electron-donating color-forming organic compound, (ii) an electron-accepting compound, and (iii) a reaction medium that controls the color reaction of (i) and (ii), and the non-color-changing pattern contains resin particles or microcapsule pigment, and the average particle diameter of the reversible thermochromic microcapsule pigment and the resin particles or microcapsule pigment are approximately the same.

4. 4. A reversible thermochromic printed matter according to claim 3, wherein the resin particles or microcapsule pigments contained in the non-color-changing pattern contain a non-color-changing colorant, or the surfaces of the resin particles or microcapsule pigments are coated with a non-color-changing colorant.

5. The average particle diameter (L １ ) and the average particle diameter (L ２ 5. The reversible thermochromic printed matter according to claim 3 or 4, wherein ) satisfies the following formula (2): 0.7≦L ２ / L １ ≦1.3 (2)

6. 5. The reversible thermochromic printed matter according to claim 1, wherein the color of the reversible thermochromic pattern in the colored state of the reversible thermochromic material is the same color or a similar color to the color of the non-color-changing pattern.

7. The reversible thermochromic microencapsulated pigment exhibits hysteresis characteristics in the color density-temperature curve, and exhibits alternation between a colored state and a colorless state. In the process of increasing the temperature from the colored state, ３ When the temperature reaches T ３ Higher temperature T ４ In the temperature range above, the color becomes completely colorless. In the process of decreasing the temperature from the colorless state, ３ Lower temperature T ２ When the temperature reaches T ２ Lower temperature T １ It exhibits hysteresis characteristics in which it becomes completely colored in the temperature range below temperature T ４ 4. The reversible thermochromic printed matter according to claim 3, wherein the temperature is in the range of 30 to 90°C.

8. 5. The reversibly thermochromic printed matter according to claim 1, further comprising a transparent metallic luster layer covering the reversibly thermochromic design and the non-color-changing design.

9. A reversible thermochromic printed material set comprising the reversible thermochromic printed material according to any one of claims 1 to 4 and a friction body.

10. A reversibly thermochromic printed matter set comprising the reversibly thermochromic printed matter according to any one of claims 1 to 4 and a writing implement equipped with a friction member.

11. 11. The set of reversibly thermochromic printed matter according to claim 10, wherein the writing implement contains ink that can be erased by heating.

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