JP2023142355A - Ink composition for reversible thermochromic stamp and stamp using the same - Google Patents

Abstract

To provide an ink composition for reversible thermochromic stamp and a stamp using the same, which can satisfy dry resistance even when a printing surface is exposed to ambient air, allow a user to clearly view an appearance of changing a color of the ink from a chromatic color (1) to a chromatic color (2) by a temperature change, can suppress bleed through, and can obtain a printed image which can prevent damage to a good appearance of a paper surface and contamination to other paper.SOLUTION: An ink composition for reversible thermochromic stamp comprises: a reversible thermochromic pigment whose average particle diameter is 0.5-5.0 μm and which includes a reversible thermochromic composition which is formed of (a) an electron donative coloration organic compound, (b) an electron reception compound, and (c) a reaction medium for reversibly generating, in a specific temperature region, an electron transfer reaction by the components (a) and (b); a non coloration colorant; and a moisturizing agent included by 30 mass% or greater in the whole ink composition. In the ink composition for reversible thermochromic stamp, a brightness value in a state of color discharge of the reversible thermochromic pigment, is 90 or lower, and there is also provided a stamp 1 using the same ink composition for reversible thermochromic stamp.SELECTED DRAWING: Figure 4

Description

The present invention relates to a reversible thermochromic stamp ink composition and a stamp using the same. More specifically, the present invention relates to a reversible thermochromic stamp ink composition capable of producing an image whose color changes from colored (1) to colored (2) due to temperature changes, and a stamp using the same.

Conventionally, an ink composition for a stamp for obtaining a color-changing impression image that changes color from colored (1) to colored (2) depending on a temperature change has been disclosed (for example, Patent Documents 1 and 2). reference).
A non-thermochromic dye or pigment is blended into the ink composition so as to form a thermochromic image that exhibits chromatism from color (1) to color (2) due to temperature changes. It is stated that.
However, the stamp surface is exposed to the atmosphere for a long time, and it is necessary to add a large amount of humectant to the ink to prevent the ink from drying on the stamp surface. Therefore, the printed image has poor drying properties, and the ink may penetrate into the paper surface and reach the back surface, causing strike-through of the printed image, impairing its appearance, or contaminating other papers.

Japanese Patent Application Publication No. 2002-121427 Japanese Patent Application Publication No. 2015-209444

The present invention pursues the printing image obtained with this type of reversible thermochromic stamp ink composition, which satisfies drying resistance even when the stamp surface is exposed to the atmosphere, and changes color (1) due to temperature changes. A reversible thermal method that produces a clearly visible printed image with a color change (2) that does not easily cause bleed through and does not spoil the appearance of the paper or contaminate other papers. The present invention aims to provide a color-changing ink composition for stamps and a stamp using the same.

The present invention reversibly performs an electron transfer reaction between (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) the components (a) and (b) above in a specific temperature range. a reversible thermochromic pigment with an average particle diameter of 0.5 to 5.0 μm, including a reversible thermochromic composition consisting of a reaction medium to be generated, a non-chromic coloring agent, and 30% by mass or more based on the total amount of the ink composition. A reversible thermochromic stamp ink composition comprising at least a humectant and a lightness value of 90 or less in a state where the reversible thermochromic pigment is decolored is required. do.
Furthermore, the non-color-changing colorant has a maximum absorption wavelength of 380-480 nm in the range of 380-780 nm, and is a non-color-changing colorant excluding colorants that do not have an absorption wavelength of 580 nm or more. , the non-discoloring coloring agent is a dye, the humectant is (poly)glycerin, and the ink composition contains 30 to 90% by mass of the (poly)glycerin, etc. do.
Furthermore, the present invention requires a stamp comprising a stamp material having continuous pores, the stamp material being impregnated with the reversible thermochromic stamp ink composition.

The present invention satisfies drying resistance even when the stamp surface is exposed to the atmosphere, allows the appearance of color change from colored (1) to colored (2) due to temperature changes to be clearly visible, and prevents bleed-through. To provide a reversible thermochromic stamp ink composition with high commercial value, capable of producing a printed image that does not easily cause the appearance of the paper surface or stain other papers, and a stamp using the same.

1 is a graph illustrating hysteresis characteristics in a color density-temperature curve of a heat-erasable reversible thermochromic composition. 1 is a graph illustrating hysteresis characteristics in a color density-temperature curve of a reversible thermochromic composition having color memory properties. 1 is a graph illustrating hysteresis characteristics in a color density-temperature curve of a heat coloring type reversible thermochromic composition. FIG. 1 is an explanatory longitudinal cross-sectional view of an embodiment of a stamp incorporating the reversible thermochromic stamp ink composition of the present invention.

The reversible thermochromic composition comprises (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) the three essential components of a reaction medium that determines the temperature at which the color reaction of both of the above occurs. Examples include reversible thermochromic compositions of the heat-decolorable type (decolorized by heating and colored by cooling) that include at least the following.
The reversible thermochromic composition has a temperature that changes at a predetermined temperature (color change point) as described in Japanese Patent Publication No. 51-44706, Japanese Patent Publication No. 51-44707, Japanese Patent Publication No. 1-29398, etc. It changes color before and after, exhibits a decolored state in a temperature range above the high temperature side discoloration point, and a colored state in a temperature range below the low temperature side discoloration point, and of the above two states, only one specific state exists in the normal temperature range, The other state is maintained as long as the heat or cold required to bring it about is applied, but once the heat or cold is no longer applied, it returns to the state it exhibits at room temperature, with a hysteresis width ( A reversible thermochromic composition having a relatively small ΔH) of 1 to 7° C. can be used (see FIG. 1).

In addition, Japanese Patent Publication No. 4-17154, Japanese Patent Application Publication No. 7-179777, Japanese Patent Application Publication No. 7-33997, Japanese Patent Application Publication No. 8-39936, Japanese Patent Application Publication No. 2005-1369, Japanese Patent Application Publication No. 2008-280523, etc. In other words, the shape of the curve plotting the change in coloring density due to temperature change shows a relatively large hysteresis width (ΔH) of 8°C to 80°C. The discoloration follows _a very different path depending on whether the temperature is raised or lowered from a temperature higher than the discoloration temperature range. Thermal decolorization has a color memory property in a specific temperature range [temperature range between t ₂ and t ₃ (substantially two-phase retention temperature range)] where the decolorization state at a high temperature range above the color temperature (t ₄ ) A reversible thermochromic composition (which loses color when heated and develops color when cooled) can also be applied (see FIG. 2).

The hysteresis characteristic in the color density-temperature curve of the reversible thermochromic composition will be explained.
In FIG. 2, the vertical axis represents color density, and the horizontal axis represents temperature. Changes in color density due to temperature changes progress along the arrows. Here, A is a point indicating the density at a temperature t ₄ (hereinafter referred to as complete decolorization temperature) at which a completely decolorized state is reached, and B is a point indicating the density at a temperature t ₃ (hereinafter referred to as decolorization start temperature) at which decolorization starts. C is a point indicating the density at a temperature t ₂ (hereinafter referred to as the color development start temperature) at which color development starts, and D is a point indicating the density at the temperature t ₁ (hereinafter referred to as complete color development temperature) at which a complete color development state is reached. This point indicates the density at the color development temperature.
The discoloration temperature range is the temperature range between t ₁ and t ₄ , which can exhibit either a colored state or a discolored state, and is a region between t ₂ and t ₃ where there is a large difference in color density. The temperature range is the actual discoloration temperature range.
In addition, the length of the line segment EF is a measure of the contrast of discoloration, and the length of the line segment HG passing through the midpoint of the line segment EF is the temperature width (hereinafter referred to as hysteresis width ΔH) indicating the degree of hysteresis. If this ΔH value is small, only one of the two states before and after discoloration can exist in the normal temperature range. Further, when the ΔH value is large, each state before and after discoloration can be easily maintained.

Components (a), (b), and (c) contained in the reversible thermochromic pigment will be specifically explained below.
Component (a) of the present invention, that is, an electron-donating color-forming organic compound, is a component that determines color, and is a compound that donates electrons to component (b), which is a color developer, to develop color.
Examples of the electron-donating color-forming organic compounds include phthalide compounds, fluoran compounds, styrinoquinoline compounds, diazalhodamine lactone compounds, pyridine compounds, quinazoline compounds, bisquinazoline compounds, etc. Among these, phthalide compounds, fluoran compounds, Styrinoquinoline compounds and diazalhodamine lactone compounds are preferred.
Examples of the phthalide compounds include diphenylmethane phthalide compounds, phenylindolylphthalide 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 shown 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)fluorane,
3,6-dimethoxyfluorane,
3,6-di-n-butoxyfluorane,
2-methyl-6-(N-ethyl-Np-tolylamino)fluoran,
3-chloro-6-cyclohexylaminofluorane,
2-methyl-6-cyclohexylaminofluorane,
2-(2-chloroamino)-6-dibutylaminofluorane,
2-(2-chloroanilino)-6-di-n-butylaminofluorane,
2-(3-trifluoromethylanilino)-6-diethylaminofluorane,
2-(3-trifluoromethylanilino)-6-dipentylaminofluorane,
2-(dibenzylamino)-6-diethylaminofluorane,
2-(N-methylanilino)-6-(N-ethyl-Np-tolylamino)fluoran,
1,3-dimethyl-6-diethylaminofluorane,
2-chloro-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-diethylaminofluorane,
2-anilino-3-methoxy-6-diethylaminofluorane,
2-anilino-3-methyl-6-di-n-butylaminofluorane,
2-anilino-3-methoxy-6-di-n-butylaminofluorane,
2-xylidino-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-(N-ethyl-Np-tolylamino)fluoran,
1,2-benz-6-diethylaminofluorane,
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)pyrimidine-5,1'(3'H)isobenzofuran]-3'-one, 2-(diethylamino)-8-(diethylamino)-4-methyl ,
Spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1'(3'H)isobenzofuran]-3'-one, 2-(di-n-butylamino)-8-(di- -n-butylamino)-4-methyl,
spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1'(3'H)isobenzofuran]-3'-one, 2-(di-n-butylamino)-8-(diethylamino )-4-methyl,
spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1'(3'H)isobenzofuran]-3'-one, 2-(di-n-butylamino)-8-(N -ethyl-N-i-amylamino)-4-methyl,
Spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-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]xanthene]-3-one,
3',6'-bis[phenyl(3-methylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one,
3',6'-bis[phenyl(3-ethylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-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, examples of fluoranes include compounds having a substituent on the phenyl group forming the xanthene ring and also substituents on the phenyl group forming the lactone ring (e.g. , an alkyl group such as a methyl group, or a halogen atom such as a chloro group) that exhibits blue or black color.

The component (b), ie, the electron-accepting compound, is a compound that receives electrons from the component (a) and functions as a color developer for the component (a).
Examples of the electron-accepting compounds include compounds having active protons and derivatives thereof, pseudo-acidic compounds (not acids, but compounds that act as acids in the composition and cause component (a) to develop color), and electron-vacuum compounds. There are compounds selected from the group of compounds having pores, among which compounds selected from the group of compounds having active protons are preferred.
Examples of compounds having active protons 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 the like. metal salts, acidic phosphoric acid esters and their metal salts, azole compounds and their derivatives, 1,2,3-triazoles and their derivatives, and among these, those that exhibit effective thermochromic properties. A compound having a phenolic hydroxyl group is preferable because it can provide the following.
The compounds having a phenolic hydroxyl group include a wide range from monophenol compounds to polyphenol compounds, and further include bis-type, tris-type phenols, and phenol-aldehyde condensation resins. Among compounds having a phenolic hydroxyl group, those having at least two or more benzene rings are preferred. Further, 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, and a halogen group.
Examples of metals contained in the metal salt of the compound having active protons include sodium, potassium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, lead, and molybdenum. It will be done.

Specific examples are given below.
Phenol, o-cresol, tert-butylcatechol, 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-dihydroxydiphenylsulfone, 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)-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-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, and the like.
Compounds having the above-mentioned phenolic hydroxyl group can exhibit the most effective thermochromic properties, but aromatic carboxylic acids, aliphatic carboxylic acids having 2 to 5 carbon atoms, carboxylic acid metal salts, acidic phosphoric esters and their It may also be a compound selected from metal salts, 1,2,3-triazoles and derivatives thereof.

The component (c) of the reaction medium that reversibly causes the electron transfer reaction by the components (a) and (b) above in a specific temperature range will be explained.
Examples of the component (iii) include alcohols, esters, ketones, ethers, and acid amides.
When applying the above compounds to microencapsulation and secondary processing, low molecular weight compounds tend to evaporate out of the capsule when subjected to high heat treatment. The following compounds are preferably used.
As alcohols, aliphatic monohydric saturated alcohols having 10 or more carbon atoms are effective, specifically decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl Examples include alcohol, heptadecyl alcohol, octadecyl alcohol, eicosyl alcohol, docosyl alcohol, and the like.

As the esters, esters having 10 or more carbon atoms are effective, and any combination of a monohydric carboxylic acid having an aliphatic and alicyclic ring or an aromatic ring and a monohydric alcohol having an aliphatic ring and an alicyclic ring or an aromatic ring is effective. Esters, aliphatic and alicyclic acids obtained from any combination of aliphatic and alicyclic or aromatic ring-containing polyhydric carboxylic acids and aliphatic and alicyclic or aromatic ring-containing monohydric alcohols. Alternatively, examples include esters obtained from any combination of a monohydric carboxylic acid having an aromatic ring and a polyhydric alcohol having an aliphatic and alicyclic ring or an aromatic ring. Specifically, ethyl caprylate, octyl caprylate, caprylic Stearyl acid, myristyl caprate, docosyl caprate, 2-ethylhexyl laurate, n-decyl laurate, 3-methylbutyl myristate, cetyl myristate, isopropyl palmitate, neopentyl palmitate, nonyl palmitate, cyclohexyl palmitate, stearin n-butyl stearate, 2-methylbutyl stearate, 3,5,5-trimethylhexyl stearate, n-undecyl stearate, pentadecyl stearate, stearyl stearate, cyclohexylmethyl stearate, isopropyl behenate, hexyl behenate, behen Lauryl acid, behenyl behenate, cetyl benzoate, stearyl p-tert-butylbenzoate, dimyristyl phthalate, distearyl phthalate, dimyristyl oxalate, dicetyl oxalate, dicetyl malonate, dilauryl succinate, dilauryl glutarate, adipine diundecyl acid, dilauryl azelate, di-(n-nonyl) sebacate, dineopentyl 1,18-octadecylmethylenedicarboxylate, 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 Examples include distearate and the like.

Also, esters of saturated fatty acids and branched aliphatic alcohols, esters of unsaturated fatty acids or saturated fatty acids with branches or substituents and aliphatic alcohols that are branched or have 16 or more carbon atoms, cetyl butyrate, stearyl butyrate, and Ester compounds selected from behenyl butyrate are also effective.
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-ethylhexyl laurate, 1-ethylhexyl myristate, 1-ethylhexyl palmitate, 2-methylpentyl caproate, 2-methylpentyl caprylate, 2-methylpentyl caprate, 2-methylpentyl laurate, 2-stearate Methylbutyl, 2-methylbutyl stearate, 3-methylbutyl stearate, 1-methylheptyl stearate, 2-methylbutyl behenate, 3-methylbutyl behenate, 1-methylheptyl stearate, 1-methylheptyl behenate, caproic acid 1 -Ethylpentyl, 1-ethylpentyl palmitate, 1-methylpropyl stearate, 1-methyloctyl stearate, 1-methylhexyl stearate, 1,1-dimethylpropyl laurate, 1-methylpentyl caprate, palmitic acid 2-Methylhexyl, 2-methylhexyl stearate, 2-methylhexyl behenate, 3,7-dimethyloctyl laurate, 3,7-dimethyloctyl myristate, 3,7-dimethyloctyl palmitate, 3-stearate, 7-dimethyloctyl, 3,7-dimethyloctyl behenate, stearyl oleate, behenyl oleate, stearyl linoleate, behenyl linoleate, 3,7-dimethyloctyl erucate, stearyl erucate, isostearyl erucate, isostearic acid Cetyl, stearyl isostearate, 2-methylpentyl 12-hydroxystearate, 2-ethylhexyl 18-bromostearate, isostearyl 2-ketomyristate, 2-ethylhexyl 2-fluoromyristate, cetyl butyrate, stearyl butyrate, behenyl butyrate etc.

Furthermore, in order to exhibit large hysteresis characteristics with respect to the color density-temperature curve and change color, and to provide color memory depending on temperature changes, it is necessary to Carboxylic acid ester compounds exhibiting a ΔT value (melting point - clouding point), for example, carboxylic acid esters containing substituted aromatic rings in the molecule, esters of carboxylic acids containing unsubstituted aromatic rings and aliphatic alcohols having 10 or more carbon atoms. , carboxylic acid ester containing a cyclohexyl group in the molecule, ester of fatty acid with 6 or more carbon atoms and unsubstituted aromatic alcohol or phenol, ester of fatty acid with 8 or more carbon atoms and branched aliphatic alcohol, dicarboxylic acid and aromatic alcohol, or Esters of branched aliphatic alcohols, dibenzyl cinnamate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, dicetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearin, dimyristin, distearin, etc. can be mentioned.

Fatty acid ester compound obtained from an odd-numbered aliphatic monohydric alcohol having 9 or more carbon atoms and an even-numbered aliphatic carboxylic acid, n-pentyl alcohol or n-heptyl alcohol and an even-numbered aliphatic carboxylic acid having 10 to 16 carbon atoms. Fatty acid ester compounds having a total of 17 to 23 carbon atoms obtained from acids 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, lauric acid n-heptyl, n-nonyl laurate, n-undecyl laurate, n-tridecyl laurate, n-pentadecyl laurate, n-pentyl myristate, n-heptyl myristate, n-nonyl myristate, n- myristate Undecyl, 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-undersi eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate, behenic acid Examples include n-nonyl, n-undecyl behenate, n-tridecyl behenate, and n-pentadecyl behenate.

As the ketones, aliphatic ketones having a total carbon number of 10 or more are effective, such as 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, 5-undecanone, 2-decanone, -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.
Furthermore, arylalkyl ketones having a total carbon number of 12 to 24, such as n-octadecanophenone, n-heptadecanophenone, n-hexadecanophenone, n-pentadecanophenone, n-tetradecanophenone, Nophenone, 4-n-dodecaacetophenone, n-tridecanophenone, 4-n-undecanoacetophenone, n-laurophenone, 4-n-decanoacetophenone, n-undecanophenone, 4-n-nonylacetophenone, n-decanophenone, 4-n-octylacetophenone, n-nonanophenone, 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, cyclopentylphenyl Examples include ketones.

As the ethers, aliphatic ethers having a total carbon number of 10 or more are effective, such as dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, didodecyl ether, and ditriether. Decyl ether, ditetradecyl ether, dipentadecyl ether, dihexadecyl ether, dioctadecyl ether, decanediol dimethyl ether, undecane diol dimethyl ether, dodecane diol dimethyl ether, tridecane diol dimethyl ether, decane diol diethyl ether, undecane diol diethyl ether, etc. Can be mentioned.

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, and 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, caproic acid anilide - 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, palmitin Acid N-butylamide, stearic 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 Amide, lauric acid N-dodecylamide, myristic acid N-dodecylamide, palmitic acid N-dodecylamide, stearic acid N-dodecylamide, oleic acid N-dodecylamide, dilauric acid amide, dimiristic acid amide, dipalmitic acid amide , distearamide, dioleic acid amide, trilauric acid amide, trimyristic acid amide, tripalmitic acid amide, tristearic acid amide, trioleic acid amide, succinic acid amide, adipic acid amide, glutaric acid amide, malonic acid amide, azelain 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 Acid N-ethylamide, malonic acid N-ethylamide, azelaic acid N-ethylamide, succinic acid N-butylamide, adipic acid N-butylamide, glutaric acid N-butylamide, malonic acid N-butylamide, adipic acid N-octylamide, adipic acid Examples include N-dodecylamide and the like.

〔式中、Ｒ_１は水素原子又はメチル基を示し、ｍは０～２の整数を示し、Ｘ_１、Ｘ_２のいずれか一方は－（ＣＨ_２）_ｎＯＣＯＲ_２又は－（ＣＨ_２）_ｎＣＯＯＲ_２、他方は水素原子を示し、ｎは０～２の整数を示し、Ｒ_２は炭素数４以上のアルキル基又はアルケニル基を示し、Ｙ_１及びＹ_２は水素原子、炭素数１～４のアルキル基、メトキシ基、又は、ハロゲンを示し、ｒ及びｐは１～３の整数を示す。〕
前記式（１）で示される化合物のうち、Ｒ_１が水素原子の場合、より広いヒステリシス幅を有する可逆熱変色性組成物が得られるため好適であり、更にＲ_１が水素原子であり、且つ、ｍが０の場合がより好適である。
なお、式（１）で示される化合物のうち、より好ましくは下記一般式（２）で示される化合物が用いられる。

式中のＲは炭素数８以上のアルキル基又はアルケニル基を示すが、好ましくは炭素数１０～２４のアルキル基、更に好ましくは炭素数１２～２２のアルキル基である。
前記化合物として具体的には、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を例示できる。 Further, as the component (iii), a compound represented by the following general formula (1) can also be used.

[In the formula, R ₁ represents a hydrogen atom or a methyl group, m represents an integer of 0 to 2, and either X ₁ or X ₂ is -(CH ₂ ) _n OCOR ₂ or -(CH ₂ ) _n COOR ₂ , the other represents a hydrogen atom, n represents an integer of 0 to 2, R ₂ represents an alkyl group or alkenyl group having 4 or more carbon atoms, Y ₁ and Y ₂ are hydrogen atoms, and C 1 to 4 represents an alkyl group, methoxy group, or halogen, and r and p represent integers of 1 to 3. ]
Among the compounds represented by the formula (1), when R ₁ is a hydrogen atom, it is preferable because a reversible thermochromic composition having a wider hysteresis width can be obtained, and furthermore, R ₁ is a hydrogen atom, and , m is more preferably 0.
Note that among the compounds represented by formula (1), a compound represented by the following general formula (2) is more preferably used.

R in the formula represents an alkyl group or an 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.
Specifically, the compounds include 4-benzyloxyphenylethyl octoate, 4-benzyloxyphenylethyl nonanoate, 4-benzyloxyphenylethyl decanoate, 4-benzyloxyphenylethyl undecanoate, and dodecanoic acid. -4-benzyloxyphenylethyl, -4-benzyloxyphenylethyl tridecanoate, -4-benzyloxyphenylethyl tetradecanoate, -4-benzyloxyphenylethyl pentadecanoate, -4-benzyloxyphenylethyl hexadecanoate, heptadecanoic acid Examples include -4-benzyloxyphenylethyl and -4-benzyloxyphenylethyl octadecanoate.

（式中、Ｒは炭素数８以上のアルキル基又はアルケニル基を示し、ｍ及びｎはそれぞれ１～３の整数を示し、Ｘ及びＹはそれぞれ水素原子、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基、ハロゲンを示す。）
前記化合物として具体的には、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－ジフェニルメチルを例示できる。 Furthermore, a compound represented by the following general formula (3) can also be used as the component (iii).

(In the formula, R represents an alkyl group or an 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, or a carbon Indicates an alkoxy group of numbers 1 to 4 and a halogen.)
Specifically, the compounds include 1,1-diphenylmethyl octoate, 1,1-diphenylmethyl nonanoate, 1,1-diphenylmethyl decanoate, 1,1-diphenylmethyl undecanoate, and 1,1-diphenylmethyl dodecanoate. Diphenylmethyl, 1,1-diphenylmethyl tridecanoate, 1,1-diphenylmethyl tetradecanoate, 1,1-diphenylmethyl pentadecanoate, 1,1-diphenylmethyl hexadecanoate, 1,1-diphenylmethyl heptadecanoate, octadecanoic acid An example is 1,1-diphenylmethyl.

（式中、Ｘは水素原子、炭素数１乃至４のアルキル基、メトキシ基、ハロゲン原子のいずれかを示し、ｍは１乃至３の整数を示し、ｎは１乃至２０の整数を示す。）
前記化合物としては、マロン酸と２－〔４－(４－クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、こはく酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、こはく酸と２－〔４－(３－メチルベンジルオキシ）フェニル）〕エタノールとのジエステル、グルタル酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、グルタル酸と２－〔４－(４－クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、アジピン酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、ピメリン酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、スベリン酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、スベリン酸と２－〔４－(３－メチルベンジルオキシ）フェニル）〕エタノールとのジエステル、スベリン酸と２－〔４－(４－クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、スベリン酸と２－〔４－(２，４－ジクロロベンジルオキシ）フェニル）〕エタノールとのジエステル、アゼライン酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、セバシン酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、１，１０－デカンジカルボン酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２－（４－ベンジルオキシフェニル）エタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２－〔４－(２－メチルベンジルオキシ）フェニル）〕エタノールとのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (4) can also be used as the component (iii).

(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 compounds include diesters of malonic acid and 2-[4-(4-chlorobenzyloxy)phenyl)]ethanol, diesters of succinic acid and 2-(4-benzyloxyphenyl)ethanol, and diesters of succinic acid and 2-[4-benzyloxyphenyl]ethanol. Diester with [4-(3-methylbenzyloxy)phenyl)]ethanol, diester with glutaric acid and 2-(4-benzyloxyphenyl)ethanol, glutaric acid with 2-[4-(4-chlorobenzyloxy)] phenyl)] diester with ethanol, diester with adipic acid and 2-(4-benzyloxyphenyl)ethanol, diester with pimelic acid and 2-(4-benzyloxyphenyl)ethanol, diester with suberic acid and 2-(4- benzyloxyphenyl) ethanol, suberic acid and 2-[4-(3-methylbenzyloxy)phenyl)] ethanol diester, suberic acid and 2-[4-(4-chlorobenzyloxy)phenyl)] Diester with ethanol, diester with suberic acid and 2-[4-(2,4-dichlorobenzyloxy)phenyl)]ethanol, diester with azelaic acid and 2-(4-benzyloxyphenyl)ethanol, with sebacic acid Diester with 2-(4-benzyloxyphenyl)ethanol, diester with 1,10-decanedicarboxylic acid and 2-(4-benzyloxyphenyl)ethanol, diester with 1,18-octadecanedicarboxylic acid and 2-(4-benzyl) Examples include diesters with oxyphenyl)ethanol and diesters with 1,18-octadecanedicarboxylic acid and 2-[4-(2-methylbenzyloxy)phenyl)]ethanol.

（式中、Ｒは炭素数１乃至２１のアルキル基又はアルケニル基を示し、ｎは１乃至３の整数を示す。）
前記化合物としては、１，３－ビス（２－ヒドロキシエトキシ）ベンゼンとカプリン酸とのジエステル、１，３－ビス（２－ヒドロキシエトキシ）ベンゼンとウンデカン酸とのジエステル、１，３－ビス（２－ヒドロキシエトキシ）ベンゼンとラウリン酸とのジエステル、１，３－ビス（２－ヒドロキシエトキシ）ベンゼンとミリスチン酸とのジエステル、１，４－ビス（ヒドロキシメトキシ）ベンゼンと酪酸とのジエステル、１，４－ビス（ヒドロキシメトキシ）ベンゼンとイソ吉草酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンと酢酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンとプロピオン酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンと吉草酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンとカプロン酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンとカプリル酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンとカプリン酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンとラウリン酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンとミリスチン酸とのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (5) can also be used as the component (iii).

(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 compounds 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, and a diester of 1,3-bis(2-hydroxyethoxy)benzene and undecanoic acid. -Diester of benzene and lauric acid, diester of 1,3-bis(2-hydroxyethoxy)benzene and myristic acid, diester of 1,4-bis(hydroxymethoxy)benzene and butyric acid, 1,4 - Diesters of bis(hydroxymethoxy)benzene and isovaleric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and acetic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and propionic acid Diester, diester of 1,4-bis(2-hydroxyethoxy)benzene and valeric acid, diester of 1,4-bis(2-hydroxyethoxy)benzene and caproic acid, 1,4-bis(2-hydroxyethoxy) ) diester of benzene and caprylic acid, diester of 1,4-bis(2-hydroxyethoxy)benzene and capric acid, diester of 1,4-bis(2-hydroxyethoxy)benzene and lauric acid, 1,4 An example is a diester of -bis(2-hydroxyethoxy)benzene and myristic acid.

（式中、Ｘは水素原子、炭素数１乃至４のアルキル基、炭素数１乃至４のアルコキシ基、ハロゲン原子のいずれかを示し、ｍは１乃至３の整数を示し、ｎは１乃至２０の整数を示す。）
前記化合物としては、こはく酸と２－フェノキシエタノールとのジエステル、スベリン酸と２－フェノキシエタノールとのジエステル、セバシン酸と２－フェノキシエタノールとのジエステル、１，１０-デカンジカルボン酸と２－フェノキシエタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２－フェノキシエタノールとのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (6) can also be used as the component (iii).

(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; )
The compounds include diesters of succinic acid and 2-phenoxyethanol, diesters of suberic acid and 2-phenoxyethanol, diesters of sebacic acid and 2-phenoxyethanol, diesters of 1,10-decanedicarboxylic acid and 2-phenoxyethanol, An example is a diester of 1,18-octadecanedicarboxylic acid and 2-phenoxyethanol.

（式中、Ｒは炭素数４乃至２２のアルキル基、シクロアルキルアルキル基、シクロアルキル基、炭素数４乃至２２のアルケニル基のいずれかを示し、Ｘは水素原子、炭素数１乃至４のアルキル基、炭素数１乃至４のアルコキシ基、ハロゲン原子のいずれかを示し、ｎは０又は１を示す。）
前記化合物としては、４－フェニル安息香酸デシル、４－フェニル安息香酸ラウリル、４－フェニル安息香酸ミリスチル、４－フェニル安息香酸シクロヘキシルエチル、４－ビフェニル酢酸オクチル、４－ビフェニル酢酸ノニル、４－ビフェニル酢酸デシル、４－ビフェニル酢酸ラウリル、４－ビフェニル酢酸ミリスチル、４－ビフェニル酢酸トリデシル、４－ビフェニル酢酸ペンタデシル、４－ビフェニル酢酸セチル、４－ビフェニル酢酸シクロペンチル、４－ビフェニル酢酸シクロヘキシルメチル、４－ビフェニル酢酸ヘキシル、４－ビフェニル酢酸シクロヘキシルメチルを例示できる。 Furthermore, a compound represented by the following general formula (7) can also be used as the component (iii).

(In the formula, R represents an alkyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, a cycloalkyl group, or an alkenyl group having 4 to 22 carbon atoms, and X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. group, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, and n represents 0 or 1.)
The compounds include decyl 4-phenylbenzoate, lauryl 4-phenylbenzoate, myristyl 4-phenylbenzoate, cyclohexylethyl 4-phenylbenzoate, octyl 4-biphenylacetate, nonyl 4-biphenylacetate, and 4-biphenylacetic acid. Decyl, 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.

（式中、Ｒは炭素数３乃至１８のアルキル基、炭素数３乃至１８の脂肪族アシル基のいずれかを示し、Ｘは水素原子、炭素数１乃至３のアルキル基、炭素数１又は２のアルコキシ基、ハロゲン原子のいずれかを示し、Ｙは水素原子、メチル基のいずれかを示し、Ｚは水素原子、炭素数１乃至４のアルキル基、炭素数１又は２のアルコキシ基、ハロゲン原子のいずれかを示す。）
前記化合物としては、４－ブトキシ安息香酸フェノキシエチル、４－ペンチルオキシ安息香酸フェノキシエチル、４－テトラデシルオキシ安息香酸フェノキシエチル、４－ヒドロキシ安息香酸フェノキシエチルとドデカン酸とのエステル、バニリン酸フェノキシエチルのドデシルエーテルを例示できる。 Furthermore, a compound represented by the following general formula (8) can also be used as the component (iii).

(In the formula, R represents either an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms; represents either an alkoxy group or a halogen atom, Y represents either a hydrogen atom or a methyl group, and Z represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, or a halogen atom. )
Examples of the above compounds include phenoxyethyl 4-butoxybenzoate, phenoxyethyl 4-pentyloxybenzoate, phenoxyethyl 4-tetradecyloxybenzoate, ester of phenoxyethyl 4-hydroxybenzoate and dodecanoic acid, and phenoxyethyl vanillate. An example is dodecyl ether.

（式中、Ｒは炭素数４乃至２２のアルキル基、炭素数４乃至２２のアルケニル基、シクロアルキルアルキル基、シクロアルキル基のいずれかを示し、Ｘは水素原子、アルキル基、アルコキシ基、ハロゲン原子のいずれかを示し、Ｙは水素原子、アルキル基、アルコキシ基、ハロゲン原子のいずれかを示し、ｎは０又は１を示す。）
前記化合物としては、ｐ－ヒドロキシ安息香酸オクチルの安息香酸エステル、ｐ－ヒドロキシ安息香酸デシルの安息香酸エステル、ｐ－ヒドロキシ安息香酸ヘプチルのｐ－メトキシ安息香酸エステル、ｐ－ヒドロキシ安息香酸ドデシルのo-メトキシ安息香酸エステル、ｐ－ヒドロキシ安息香酸シクロヘキシルメチルの安息香酸エステルを例示できる。 Furthermore, a compound represented by the following general formula (9) can also be used as the component (iii).

(In the formula, R represents an alkyl group having 4 to 22 carbon atoms, an alkenyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, or a cycloalkyl group, and X represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen (Y represents either a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and n represents 0 or 1.)
Examples of the above compounds include benzoate ester of octyl p-hydroxybenzoate, benzoate ester of decyl p-hydroxybenzoate, p-methoxybenzoate ester of heptyl p-hydroxybenzoate, and o-dodecyl p-hydroxybenzoate. Examples include methoxybenzoic acid ester and benzoic acid ester of cyclohexylmethyl p-hydroxybenzoate.

（式中、（式中、Ｒは炭素数３乃至１８のアルキル基、炭素数６乃至１１のシクロアルキルアルキル基、炭素数５乃至７のシクロアルキル基、炭素数３乃至１８のアルケニル基のいずれかを示し、Ｘは水素原子、炭素数１乃至４のアルキル基、炭素数１乃至３のアルコキシ基、ハロゲン原子のいずれかを示し、Ｙは水素原子、炭素数１乃至４のアルキル基、メトキシ基、エトキシ基、ハロゲン原子のいずれかを示す。）
前記化合物としては、ｐ－ヒドロキシ安息香酸ノニルのフェノキシエチルエーテル、ｐ－ヒドロキシ安息香酸デシルのフェノキシエチルエーテル、ｐ－ヒドロキシ安息香酸ウンデシルのフェノキシエチルエーテル、バニリン酸ドデシルのフェノキシエチルエーテルを例示できる。 Furthermore, a compound represented by the following general formula (10) can also be used as the component (iii).

(wherein, R is 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, or an alkenyl group having 3 to 18 carbon atoms. X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogen atom, and Y represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a methoxy group. group, ethoxy group, or halogen atom.)
Examples of the compounds 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.

（式中、Ｒは炭素数３乃至８のシクロアルキル基又は炭素数４乃至９のシクロアルキルアルキル基を示し、ｎは１乃至３の整数を示す。）
前記化合物としては、１，３－ビス（２－ヒドロキシエトキシ）ベンゼンとシクロヘキサンカルボン酸とのジエステル、１，４－ビス（２－ヒドロキシエトキシ）ベンゼンとシクロヘキサンプロピオン酸とのジエステル、１，３－ビス（２－ヒドロキシエトキシ）ベンゼンとシクロヘキサンプロピオン酸とのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (11) can also be used as the component (iii).

(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 compounds 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. An example is a diester of (2-hydroxyethoxy)benzene and cyclohexanepropionic acid.

（式中、Ｒは炭素数３乃至１７のアルキル基、炭素数３乃至８のシクロアルキル基、炭素数５乃至８のシクロアルキルアルキル基を示し、Ｘは水素原子、炭素数１乃至５のアルキル基、メトキシ基、エトキシ基、ハロゲン原子を示し、ｎは１乃至３の整数を示す。）
前記化合物としては、４－フェニルフェノールエチレングリコールエーテルとシクロヘキサンカルボン酸とのジエステル、４－フェニルフェノールジエチレングリコールエーテルとラウリン酸とのジエステル、４－フェニルフェノールトリエチレングリコールエーテルとシクロヘキサンカルボン酸とのジエステル、４－フェニルフェノールエチレングリコールエーテルとオクタン酸とのジエステル、４－フェニルフェノールエチレングリコールエーテルとノナン酸とのジエステル、４－フェニルフェノールエチレングリコールエーテルとデカン酸とのジエステル、４－フェニルフェノールエチレングリコールエーテルとミリスチン酸とのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (12) can also be used as the component (iii).

(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, and X is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. group, methoxy group, ethoxy group, halogen atom, n is an integer from 1 to 3.)
Examples of the compounds 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, - Diester of phenylphenol ethylene glycol ether and octanoic acid, diester of 4-phenylphenol ethylene glycol ether and nonanoic acid, diester of 4-phenylphenol ethylene glycol ether and decanoic acid, 4-phenylphenol ethylene glycol ether and myristin Examples include diesters with acids.

Furthermore, specific alkoxyphenol compounds having a linear or side chain alkyl group having 3 to 18 carbon atoms are used as electron-accepting compounds (Japanese Unexamined Patent Application Publication No. 11-129623, JP-A No. 11-5973), Heat coloring type using hydroxybenzoic acid ester (Japanese Patent Publication No. 2001-105732) or gallic acid ester (Japanese Patent Publication No. 51-44706, Japanese Patent Application Publication No. 2003-253149). It is also possible to apply a reversible thermochromic composition (which disappears upon cooling) (see FIG. 3).

The reversible thermochromic composition has the components (a), (b), and (c) as essential components, and the proportion of each component depends on the concentration, color change temperature, color change form, and type of each component. In general, the component ratio at which desired properties can be obtained is (a) component 1 to (b) component 0.1 to 100, preferably 0.1 to 50, more preferably 0.5 to 20, The component (c) ranges from 5 to 200, preferably from 5 to 100, more preferably from 10 to 100 (all of the above ratios are parts by mass).

Furthermore, various light stabilizers can be added if necessary.
The light stabilizer is contained in order to prevent photodeterioration of the reversible thermochromic composition consisting of components (a), (b), and (c), and is 0.3% by mass of component (a). It is contained in a proportion of ~24% by weight, preferably 0.3~16% by weight. Among the light stabilizers, the ultraviolet absorber effectively blocks ultraviolet rays contained in sunlight and the like, thereby preventing photodeterioration caused by the excited state caused by the photoreaction of component (a). Furthermore, antioxidants, singlet oxygen quenchers, superoxide anion quenchers, ozone quenchers, and the like suppress oxidation reactions caused by light.
The light stabilizers may be used alone or in combination of two or more.

The reversible thermochromic composition is used as a reversible thermochromic pigment by being dispersed in a thermoplastic resin or thermosetting resin, or by being encapsulated in microcapsules.
Note that microencapsulation can be carried out using known interfacial polymerization methods, in-situ polymerization methods, in-liquid curing coating methods, phase separation methods from aqueous solutions, phase separation methods from organic solvents, melt-dispersion cooling methods, and in-air suspension coating methods. , spray drying method, etc., which are appropriately selected depending on the application. Furthermore, depending on the purpose, a secondary resin film can be further provided on the surface of the microcapsules to impart durability or to modify the surface characteristics for practical use.
It is preferable that the microcapsule pigment has an inclusion/wall film ratio in the range of 7/1 to 1/1 (mass ratio), and when the ratio of the wall film is within the above range, the color density and It is possible to prevent a decrease in sharpness, and more preferably the ratio of inclusions/wall film is 6/1 to 1/1 (mass ratio).
By encapsulating the pigment in the microcapsules, a chemically and physically stable pigment can be constructed.

The average particle diameter of the reversible thermochromic pigment is within the range of 0.5 to 5.0 μm, preferably 0.5 to 3.0 μm, and more preferably 1.0 to 3.0 μm, which satisfies practicality.
Since the average particle size is in the range of 0.5 to 5.0 μm, the reversible thermochromic pigment is difficult to penetrate into the paper and is present in large quantities on the paper surface. It can prevent the non-discoloring colorant from penetrating into the inside, and it can also prevent the non-discoloring colorant from being visible from the back side of the paper due to print-through, and also prevent it from contaminating other paper located below. be able to.
The reversible thermochromic pigment having an average particle diameter in the range of 0.5 to 5 μm preferably accounts for 70 volume % or more, more preferably 80 volume % or more of the total reversible thermochromic pigment, and 70 volume % or more. If it is less than %, it becomes difficult to prevent the non-discoloring colorant from bleeding through.
In addition, to measure the particle size and average particle size, the area of the particle is determined using the image analysis particle size distribution measurement software "Macview" manufactured by Mountech, and the projected area circle equivalent diameter (Heywood) is calculated from the area of the particle area. This is the value measured as the particle diameter and average particle diameter of particles equivalent to an equal volume sphere based on the calculated value. In addition, if the particle diameter of all or most of the particles exceeds 0.2 μm, equal volume spheres should be measured by the Coulter method using a particle size distribution analyzer (manufactured by Beckman Coulter, Inc., product name: Multisizer 4e). It is also possible to measure the particle size of the corresponding particles and the average particle size.
Furthermore, using a laser diffraction/scattering particle size distribution measuring device (device name: LA-960V2, manufactured by Horiba, Ltd.) that was calibrated based on the values measured using a measuring device using the Coulter method, The particle diameter and average particle diameter (median diameter) may be measured.

Next, a stamp ink composition containing the reversible thermochromic pigment will be described.
The blending ratio of the reversible thermochromic pigment is 10 to 40% by weight, preferably 10 to 35% by weight, and more preferably 10 to 30% by weight based on the total amount of the ink composition.
If it is less than 10% by mass, the coloring density tends to decrease, and if it exceeds 40% by mass, the dispersion stability in the ink composition becomes poor.

By incorporating a non-thermochromic coloring agent into the ink composition, a thermochromic print image that exhibits chromatism from colored (1) to colored (2) with a different color due to temperature changes can be formed.
As the non-discoloring colorant, general dyes and pigments can be used, and dyes that can exhibit various vivid colors are preferably used.
As the dye, an acid dye, a basic dye, or a direct dye can be used.
The pigments include inorganic pigments such as carbon black and ultramarine blue, azo pigments, phthalocyanine pigments, indigo pigments, thioindigo pigments, threne pigments, quinacridone pigments, anthraquinone pigments, sulon pigments, diketopyrrolopyrrole pigments, and dioxazine. Organic pigments and fluorescent pigments such as perylene pigments, perinone pigments, and isoindolinone pigments can be used.
In addition, the non-color-changing colorant has a maximum absorption wavelength of 380-480 nm in the visible light range of 380-780 nm, and excludes colorants that do not have an absorption wavelength of 580 nm or more. That is, it is preferable to exclude a yellow colorant (yellow, a color similar to yellow), and the tautochromic color change from color (1) to color (2) can be clearly recognized.
To explain why non-color-changing colorants are used, excluding colorants whose maximum absorption wavelength is 380 to 480 nm and which does not have an absorption wavelength of 580 nm or more, yellow colorants are difficult to visually recognize; This is because although it is difficult to visually recognize the strike-through of the printed image, it is difficult to clearly visually recognize the tautochromic color change from color (1) to color (2), which is a different color.
In addition, the reversible thermochromic pigment and the non-chromatic coloring agent exhibit a tautochromic color change from colored (1) to colored (2) with a different tone using pigments of the same color. The color-changing colorant can be made to exhibit a tautochromic color change from a color (1) to a color (2) having a different hue by using pigments of different colors.

The ink composition for stamps contains a humectant in an amount of 30% by mass or more, preferably 30 to 90% by mass, more preferably 40 to 90% by mass based on the total amount of the ink composition, to suppress drying of the stamp surface. can do.
The humectant used in the present invention is not particularly limited as long as it can be generally used as a humectant, and includes (poly)glycerin.
As the (poly)glycerin, glycerin, diglycerin, triglycerin, tetraglycerin, pentaglycerin, and hexaglycerin are used, preferably glycerin, diglycerin, and triglycerin are used, and glycerin is more preferably used.

If necessary, water or a water-soluble organic solvent may be added as a medium to the stamp ink composition.
Examples of the water-soluble organic solvent include glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,3-butylene glycol, and ethylene glycol monomethyl ether, and their lower alkyl ethers, 2-pyrrolidone, and N-vinylpyrrolidone. , urea, etc., and propylene glycol is preferably used.

Furthermore, a thickener and a binder resin can be added as necessary.
The thickeners include xanthan gum, welan gum, succinoglycan (average molecular weight of about 1 million to 8 million), which is an organic acid-modified heteropolysaccharide whose constituent monosaccharides are glucose and galactose, guar gum, locust bean gum and its derivatives, hydroxy Ethylcellulose, alginate alkyl esters, polymers with a molecular weight of 100,000 to 150,000 whose main components are methacrylic acid alkyl esters, glycomannan, thickening polysaccharides with gelling ability extracted from seaweed such as agar and carrageenan, Benzylidene sorbitol and benzylidene xylitol or derivatives thereof, crosslinkable acrylic acid polymer, inorganic fine particles, polyglycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene castor oil, polyoxyethylene lanolin/lanolin alcohol・Examples include nonionic surfactants with an HLB value of 8 to 12, such as beeswax derivatives, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, fatty acid amide, and salts of dialkyl or dialkenyl sulfosuccinic acids. They can be used alone or in combination.
etc.
As the thickener, an alkali-soluble acrylic emulsion is preferably used.
When an alkali-soluble acrylic emulsion is used as the thickener, the pH of the ink composition is adjusted to 6 to 11, preferably 7 to 11, more preferably 7 to 10.

The binder resin is used to adjust the adhesion and viscosity of a printed image, and includes resin emulsions, alkali-soluble resins, and water-soluble resins.
Examples of the resin emulsion include polyacrylic acid ester, styrene-acrylic acid copolymer, polyvinyl acetate, ethylene-vinyl acetate copolymer, ethylene-vinyl chloride copolymer, methacrylic acid-maleic acid copolymer, and ethylene-vinyl chloride copolymer. Examples include aqueous dispersions of methacrylic acid copolymers, α-olefin-maleic acid copolymers, polyesters, and polyurethanes, and examples of the alkali-soluble resins include styrene-maleic acid copolymers and ethylene-maleic acid copolymers. , styrene-acrylic acid copolymer, etc. Examples of the water-soluble resin include polyvinyl alcohol, polyvinyl butyral, etc., and they can be used alone or in combination of two or more.

In addition, a pH adjuster, a preservative, a fungicide, etc. can be added as necessary.
Examples of the pH adjuster include inorganic salts such as ammonia, sodium carbonate, sodium phosphate, sodium hydroxide, and sodium acetate, and organic basic compounds such as water-soluble amine compounds such as triethanolamine and diethanolamine.
The preservatives or antifungal agents include carbolic acid, sodium salt of 1,2-benzisothiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6 -tetrachloro-4-(methylsulfonyl)pyridine and the like.
In addition, antifoaming agents such as fluorosurfactants, nonionic, anionic, and cationic surfactants, and dimethylpolysiloxane, which improve the permeability of solvents, can also be added.

The ink composition for stamps preferably has an ink viscosity of 3000 to 10000 mPa·s, more preferably 3500 to 7000 mPa·s, even more preferably 4000 mPa·s, as measured at 25° C. and 6 rpm using a BL type viscometer. ~6000 mPa・s, and the thixotropy (ink viscosity measured at 6 rpm/ink viscosity measured at 60 rpm) is preferably 1.1 to 2.5, more preferably 1.2 to 2.0. be.
When the ink viscosity is less than 3000 mPa·s, the printed image formed on the paper surface using the ink composition tends to bleed. If it exceeds 10,000 mPa・s, the fluidity of the reversible thermochromic pigment in the continuous pores will be insufficient, making it impossible to ensure smooth flow of the ink composition onto the stamp surface, resulting in the formation of an unclear print image due to continuous stamping operations. be done.
If the thixotropy is less than 1.1, the printed image formed on paper using the ink composition tends to bleed, and if it exceeds 2.5, the fluidity of the reversible thermochromic pigment in the continuous pores is insufficient. , it becomes impossible to ensure smooth flow of the ink composition onto the stamp surface, and an unclear print image is formed due to continuous stamping operations.

The brightness value of the reversible thermochromic pigment of the ink composition for a reversible thermochromic stamp is 90 or less, preferably 88 or less, more preferably 85 or less.
The brightness value was measured by uniformly applying 10 g/ ^m2 of the reversible thermochromic stamp ink composition on white paper with a brightness value of 92 and drying it.The reversible thermochromic pigment in the reversible thermochromic layer formed was decolorized. The brightness value in this state can be measured using a fluorescence spectrodensitometer [FD-7, manufactured by Konica Minolta, Inc.].
Further, the absorption wavelength and maximum absorption wavelength of the non-chromic coloring agent in a state where the reversible thermochromic pigment is decolored can be measured using an ultraviolet-visible near-infrared spectrophotometer [V670ST, manufactured by JASCO Corporation].

The ink composition for a stamp is used as an ink composition for a stamp pad and an ink composition for a stamp provided with a stamp material having continuous pores.
A stamp pad may be obtained by impregnating a stamp pad with the ink composition for a stamp pad to supply the ink composition to the stamp surface of the stamp to be brought into contact, or an ink composition for a stamp provided with a stamp material having continuous pores may be impregnated with the ink composition for a stamp pad to provide the ink composition to the stamp surface of the stamp to be contacted. A stamp can be obtained by impregnating the stamp material of a stamp with a stamp material having the above-mentioned properties.
A stamp with a stamp material having continuous pores is made by impregnating an ink composition into a rubber-like elastic body having continuous pores, which is the stamp material, and when it is pressed against the target surface, the ink composition is released from the openings of the continuous pores into the target surface. The surface shape of the stamp is transferred to the surface. Areas where transfer is not desired are recessed or the openings are closed to prevent the ink composition from adhering to the target surface.
The stamp material having continuous pores is preferably housed in a stamp base material so that its stamp surface is exposed, and the exposed surface is preferably provided with a cap to prevent the ink composition from drying out when not in use or from being contaminated by accidental contact.
Note that an ink storage portion for supplying an ink composition to the stamp material may be provided at the rear of the stamp material having continuous pores.

The printed image formed by the ink composition can be discolored by rubbing with a finger or by applying a heating or cooling tool.
Examples of the heating tool include an electrical heating discoloration tool equipped with a resistance heating element, a heat discoloration tool filled with hot water, etc., and a hair dryer. Preferably, a friction member is used as a means for changing color by a simple method. used.
As the friction member, an elastic body such as an elastomer or a plastic foam that has a rich elastic feel and can generate appropriate friction and generate frictional heat during rubbing is suitable.
Note that an eraser can be used to rub the printed image, but since eraser scum is generated during friction, the above-mentioned friction member that hardly generates eraser scum is preferably used.
As the material of the friction member, silicone resin, SEBS resin (styrene ethylene butylene styrene block copolymer), polyester resin, polyester elastomer, etc. are used.
Although a stamp set can be obtained by combining the friction member with a stamp and a friction body which is a separate member of an arbitrary shape, by providing the friction member on the stamp, the stamp set becomes superior in portability.
Examples of the cooling device include a cold color changing device using a Peltier element, a cold color changing device filled with a refrigerant such as cold water or ice chips, and a refrigerator or freezer.

Examples are described below. Note that parts in the examples are parts by mass.
Example 1
Preparation of reversible thermochromic microcapsule pigment A
(a) As a component, spiro[5H-(1)benzopyrano(2,3-d)pyrimidine-5,1'(3'H)isobenzofuran]-3'-one, 2-(dibutylamino)-8-( 1.0 parts of (dipentylamino)-4-methyl, 6.0 parts of 2,2-bis(4'-hydroxyphenyl)-hexafluoropropane as component (b), 4-benzyloxyphenyl caprate as component (c) A reversible thermochromic composition with color memory consisting of 50.0 parts of ethyl was dissolved by heating, and a solution was prepared by mixing 30.0 parts of an aromatic isocyanate prepolymer and 40.0 parts of a co-solvent as a wall material. After emulsifying and dispersing in an 8% aqueous polyvinyl alcohol solution and continuing stirring while heating, 2.5 parts of a water-soluble aliphatic modified amine was added and stirring was continued to form a reversible thermochromic microcapsule pigment suspension. Obtained.
The suspension was centrifuged to isolate reversible thermochromic microcapsule pigment A.
The average particle diameter of the microcapsule pigment is 2.5 μm, t1: -20°C, t2: -10°C, t3: 48°C, t4: 58°C, ΔH: 68°C, reversible thermochromic composition. :Wall film=2.6:1.0, the color changed reversibly from pink to colorless and from colorless to pink.

Preparation of ink composition for reversible thermochromic stamp Reversible thermochromic microcapsule pigment A 17.5 parts Blue dye [Water Blue 106L (NP)] 1.0 part Humectant (glycerin) 50.0 parts Resin emulsion A 13 .2 parts [Urethane resin emulsion, solid content acid value 5.6, NeoRezR-650 (trade name), manufactured by Kusumoto Kasei Co., Ltd., solid content 38%]
pH adjuster (triethanolamine) 0.5 parts Thickener 4.0 parts [Primal TT935 (trade name), manufactured by Rohm & Haas Japan Co., Ltd.]
Penetrant: 0.5 parts Preservative: 0.2 parts Water: 13.1 parts The above formulations were mixed to obtain a reversible thermochromic stamp ink composition that reversibly changes from purple to blue and from blue to purple. .

Example 2
Preparation of reversible thermochromic microcapsule pigment B
(a) Component: 1.5 parts of 3',6'-bis[phenyl(3-methylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one; It has color memory properties, consisting of 6.0 parts of 2,2-bis(4'-hydroxyphenyl)-hexafluoropropane as the (b) component and 50.0 parts of 4-benzyloxyphenylethyl caprate as the (c) component. A reversible thermochromic composition was dissolved by heating, and a solution containing 30.0 parts of an aromatic isocyanate prepolymer and 40.0 parts of a co-solvent as a wall film material was emulsified and dispersed in an 8% aqueous polyvinyl alcohol solution. After continuing stirring while warming, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was continued to obtain a reversible thermochromic microcapsule pigment suspension.
The suspension was centrifuged to isolate reversible thermochromic microcapsules B.
The average particle diameter of the microcapsule pigment is 2.5 μm, t1: -20°C, t2: -10°C, t3: 48°C, t4: 58°C, ΔH: 68°C, reversible thermochromic composition. :Wall film=2.6:1.0, the color changed reversibly from blue to colorless and from colorless to blue.

Preparation of ink composition for reversible thermochromic stamps Microcapsule pigment B 17.5 parts Vermilion dye (Daiwa IJ Red 319H) 0.1 part Moisturizer (glycerin) 50.0 parts Resin emulsion A 13.2 parts [Urethane-based Resin emulsion, solid content acid value 5.6, NeoRezR-650 (product name), manufactured by Kusumoto Kasei Co., Ltd., solid content 38%]
pH adjuster (triethanolamine) 0.5 parts Thickener 4.0 parts [Primal TT935 (trade name), manufactured by Rohm & Haas Japan Co., Ltd.]
Penetrant: 0.5 parts Preservative: 0.2 parts Water: 14.0 parts The above formulations were mixed to obtain a reversible thermochromic stamp ink composition that reversibly changes from purple to vermilion and from blue to vermilion. .

Preparation of reversible thermochromic microcapsule pigment C
(a) 3.0 parts of 1,3-dimethyl-6-diethylaminofluorane as component, 3.0 parts of 4,4'-(2-ethylhexane-1,1-diyl)diphenol as component (b), A reversible thermochromic composition with color memory, consisting of 5.0 parts of 2,2-bis(4'-hydroxyphenyl)-hexafluoropropane and 50.0 parts of 4-benzyloxyphenylethyl caprate as component (c). A mixture of 30.0 parts of an aromatic isocyanate prepolymer and 40.0 parts of a co-solvent as a wall film material was emulsified and dispersed in an 8% polyvinyl alcohol aqueous solution, and stirred while heating. After this, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was continued to obtain a reversible thermochromic microcapsule pigment suspension.
The suspension was centrifuged to isolate reversible thermochromic microcapsules C.
The average particle diameter of the microcapsule pigment is 2.5 μm, t1: -20°C, t2: -10°C, t3: 48°C, t4: 58°C, ΔH: 68°C, reversible thermochromic composition. :Wall film=2.6:1.0, the color changed reversibly from orange to colorless and from colorless to orange.

The table below shows the formulations of the examples. In Examples 3 to 7, reversible thermochromic stamp ink compositions were obtained in the same manner as in Example 1.

The table below shows the formulations of comparative examples. In Comparative Examples 1 to 4, reversible thermochromic stamp ink compositions were obtained in the same manner as in Example 1.

Measurement of brightness value, absorption wavelength, and maximum absorption wavelength 10 g/m ² of each of the reversible thermochromic stamp ink compositions of Examples 1 to 7 and Comparative Examples 1 to 4 was uniformly applied to white paper with a brightness value of 92. The brightness value of the reversible thermochromic pigment in the reversibly thermochromic layer formed by drying was measured using a fluorescence spectrodensitometer [FD-7, manufactured by Konica Minolta Co., Ltd.], and was measured from 380 nm to 800 nm. The absorption wavelength and maximum absorption wavelength were measured using an ultraviolet-visible near-infrared spectrophotometer [V670ST, manufactured by JASCO Corporation].

Preparation of reversible thermochromic stamp Each of the ink compositions for reversible thermochromic stamps of Examples 1 to 7 and Comparative Examples 1 to 4 was poured into a stamp material (ethylene vinyl acetate copolymer) having continuous pores, and the stamp surface was It was fixed to the stamp base material (3) so as to be exposed, and a cap (5) was fitted to obtain a stamp. A friction member made of SEBS resin was provided as a tail plug (4) at the rear end of the stamp base material (3).
The thermochromic pigment of the print image formed on the surface of white wood-free paper (68 g/m ² ) using each of the above-mentioned reversible thermochromic stamps has a color in the developed state [colored (1)] and a color in the decolored state [colored (2)], the discoloration of the printed image, and the state of show-through on the paper surface were visually observed. Note that Comparative Examples 2 and 3 do not change color, so the color of the printed image is shown.
Discoloration of the print image (color change before and after discoloration)
◎: More clearly visible.
○: Can be clearly seen.
△: Hard to visually recognize.
×: Not clearly visible.
Reverse-facing property 〇: The printed image is not visible from the back side of the paper.
×: The printed image is visible from the back side of the paper.

Brightness value, absorption wavelength region and maximum absorption wavelength of paper surface coated with reversible thermochromic stamp ink compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 4, and each reversible thermochromic stamp ink composition The thermochromic pigment of the print image obtained by the stamp containing the object has a color in the developed state [colored (1)] and a color in the decolorized state [colored (2)], the discoloration of the print image, and the print-through of the paper surface. The status is shown in the table below.

t ₁ Complete color development temperature of heat-erasable reversible thermochromic composition t ₂ Color initiation temperature of heat-erasable reversible thermochromic composition t ₃ Color erasure of heat-erasable reversible thermochromic composition Starting temperature t ₄ Complete discoloration temperature of the heat discoloration type reversible thermochromic composition T ₁ Complete discoloration temperature of the heat discoloration type reversible thermochromic composition T ₂ Complete discoloration temperature of the heat discoloration type reversible thermochromic composition Decolorization start temperature T ₃ Color development start temperature of heat coloring type reversible thermochromic composition T ₄ Complete color development temperature of heat coloring type reversible thermochromic composition ΔH Hysteresis width 1 Stamp 2 Stamp material 3 Stamp base material 4 Friction member 5 Cap

Claims (7)

A reaction medium that reversibly causes an electron transfer reaction between (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) the components (a) and (b) above in a specific temperature range. A reversible thermochromic pigment having an average particle diameter of 0.5 to 5.0 μm, including a reversible thermochromic composition comprising a reversible thermochromic composition, a non-chromic coloring agent, and a humectant in an amount of 30% by mass or more based on the total amount of the ink composition. An ink composition for a reversible thermochromic stamp comprising at least the following, wherein the ink composition for a reversible thermochromic stamp has a lightness value of 90 or less in a state in which the reversible thermochromic pigment is decolored. 2. The non-color-changing colorant has a maximum absorption wavelength in the range of 380-480 nm in the range of 380-780 nm, and is a non-color-changing colorant excluding colorants that do not have an absorption wavelength of 580 nm or more. reversible thermochromic stamp ink composition. The reversible thermochromic stamp ink composition according to claim 1 or 2, wherein the non-chromic coloring agent is a dye. The reversible thermochromic stamp ink composition according to any one of claims 1 to 3, wherein the humectant is (poly)glycerin. The ink composition for reversible thermochromic stamps according to claim 4, which contains the (poly)glycerin in an amount of 30 to 90% by mass based on the total amount of the ink composition. A stamp comprising a stamp material having continuous pores, the stamp material being impregnated with the reversible thermochromic stamp ink composition according to any one of claims 1 to 5. The stamp according to claim 6, comprising a friction body.

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