Reversible thermochromic composition and reversible thermochromic microcapsule pigment containing the same

Abstract

To provide a reversible thermochromic composition that comprises a specific sulfonyl urea compound as an electron accepting compound, so that it can express a reversible thermochromic function, and a reversible thermochromic microcapsule pigment including the same.SOLUTION: A reversible thermochromic composition comprises (a) an electron donating coloring organic compound, (b) a compound having a specific structure as an electron accepting compound, and (c) a reaction medium that causes an electron exchange reaction between the (a) component and (b) component to reversibly occur in a specific temperature region. There is also provided a reversible thermochromic microcapsule pigment including the same.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a reversible thermochromic composition and a reversible thermochromic microcapsule pigment encapsulating the same. More specifically, the present invention relates to a reversible thermochromic composition that becomes discolored at temperatures above its high-temperature discoloration point and becomes colored at temperatures below its low-temperature discoloration point, and to a reversible thermochromic microcapsule pigment encapsulating the same. [Background technology]

[0002] Several proposals have been disclosed in the past regarding reversible thermochromic compositions that change color from a colored state to a discolored state, and reversible thermochromic microcapsule pigments encapsulating the same, which contain, as essential components, an electron-donating organic color-forming compound, an electron-accepting compound, and a reaction medium that reversibly induces an electron donor-acceptor reaction between the electron-donating organic color-forming compound and the electron-accepting compound in a specific temperature range (see, for example, Patent Documents 1 to 5).

[0003] Examples of the electron-accepting compound contained in the reversible thermochromic composition include compounds selected from a group of compounds having an active proton, a group of pseudo-acidic compounds (a group of compounds that are not acids but act as acids in the reversible thermochromic composition to cause the electron-donating color-forming organic compound to develop color), a group of compounds having electron vacancies, and the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-11242 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-53853 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-106052 [Patent Document 4] Japanese Patent Application Laid-Open No. 2012-229294 [Patent Document 5] JP 2013-10810 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been achieved by examining the electron-accepting compound (b) that can be used in a reversible thermochromic composition comprising (a) an electron-donating organic color-forming compound, (b) an electron-accepting compound, and (c) a reaction medium that reversibly induces an electron donor-acceptor reaction between the components (a) and (b) in a specific temperature range. As a result, it has been found that the thermochromic property can be expressed by using a specific compound. [Means for solving the problem]

[0006] The present invention provides (a) an electron-donating color-forming organic compound; (b) a compound represented by the following formula (B) as an electron-accepting compound; (c) a reaction medium that causes a reversible electron transfer reaction between the (a) component and the (b) component in a specific temperature range; The present invention relates to a reversible thermochromic composition comprising: [ka] (In the formula, X is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogen atom; Y is an alkyl group having 1 to 6 carbon atoms. Furthermore, the present invention requires a reversible thermochromic microcapsule pigment containing the reversible thermochromic composition. Furthermore, the present invention provides a reversible thermochromic liquid composition comprising the reversible thermochromic microcapsule pigment and a vehicle. Furthermore, the present invention provides a reversibly thermochromic solid molding for coating, which comprises the reversibly thermochromic microcapsule pigment and an excipient. Furthermore, the present invention also provides a reversible thermochromic molding resin composition comprising the reversible thermochromic microcapsule pigment and a molding resin. Furthermore, the present invention requires a reversible thermochromic laminate comprising a support and a reversible thermochromic layer containing the reversible thermochromic microencapsulated pigment. [Effects of the Invention]

[0007] The present invention can provide a reversible thermochromic composition that satisfies the electron donor / acceptor reaction with the electron donor / color former organic compound (a) by using a specific sulfonylurea compound as the electron acceptor compound (b), and can further provide a reversible thermochromic composition that can fully exhibit reversible thermochromic function by mixing it with a reaction medium that reversibly induces the electron donor / acceptor reaction between the components (a) and (b) in a specific temperature range, as well as a reversible thermochromic microcapsule pigment that encapsulates the same. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a graph illustrating the hysteresis characteristics in the color density-temperature curve of a reversibly thermochromic composition that is heat-discolorable. [Figure 2] 1 is a graph illustrating the hysteresis characteristics in the color density-temperature curve of a heat-discolorable, reversible thermochromic composition having color memory properties. DETAILED DESCRIPTION OF THE INVENTION

[0009] The reversible thermochromic composition according to the present invention includes a reversible thermochromic composition of the thermal decolorization type (decolorized by heating and colored by cooling) 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 reaction of components (i) and (ii) occurs. The above-mentioned reversible thermochromic composition changes color around a predetermined temperature (color change point), exhibiting a decolorized state in the temperature range above the high-temperature color change point and a colored state in the temperature range below the low-temperature color change point.Of these two states, only one specific state exists at room temperature, and the other state is maintained while the heat or cold required to manifest that state is applied, but returns to the state it exhibits at room temperature when the application of heat or cold is removed.The composition has a relatively small hysteresis width (ΔH) (ΔH = 1 to 7°C) (see Figure 1).

[0010] Furthermore, reversible thermochromic compositions that exhibit a large hysteresis width (ΔH=8 to 70°C), i.e., the shape of the curve plotting the change in color density with temperature changes follows a significantly different path when the temperature is increased from a temperature lower than the color change temperature range than when the temperature is decreased from a temperature higher than the color change temperature range, and that exhibit a colored state in a temperature range below the complete color change temperature t1 or a discolored state in a high temperature range above the complete discoloration temperature t4, and that have color memory in a specific temperature range [the temperature range between the color change onset temperature t2 and the discoloration onset temperature t3 (a temperature range where two phases are essentially maintained)], can also be applied (see Figure 2).

[0011] Components (a), (b) and (c) will be specifically explained below.

[0012] Component (A), that is, the electron-donating organic color-forming compound, is the component that determines the color, and is a compound that donates electrons to component (B), which is the color developer, to develop color.

[0013] Examples of the electron-donating color-forming organic compound include a phthalide compound, a fluoran compound, a styrinoquinoline compound, a diazarhodamine lactone compound, a pyridine compound, a quinazoline compound, and a bisquinazoline compound. Examples of the phthalide compound include a diphenylmethane phthalide compound, a phenylindolyl phthalide compound, an indolyl phthalide compound, a diphenylmethane azaphthalide compound, a phenylindolyl azaphthalide compound, and derivatives thereof. Among these, the phenylindolyl azaphthalide compound and derivatives thereof are preferred. Examples of the fluoran compound include aminofluoran compounds, alkoxyfluoran compounds, and derivatives thereof.

[0014] Examples of compounds that can be used as component (a) are listed below. 3,3-bis(4-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-n-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-propyl-2-methylindol-3-yl)-4-azaphthalide, 3,6-bis(diphenylamino)fluoran, 3,6-bis(N-phenyl-Np-tolylamino)fluoran, 3,6-dimethoxyfluoran, 3,6-di-n-butoxyfluorane, 2-methyl-6-(N-ethyl-Np-tolylamino)fluoran, 3-chloro-6-cyclohexylaminofluoran, 2-methyl-6-cyclohexylaminofluoran, 2-chloroamino-6-di-n-butylaminofluoran, 2-(2-chloroanilino)-6-di-n-butylaminofluoran, 2-(3-trifluoromethylanilino)-6-diethylaminofluoran, 2-(3-trifluoromethylanilino)-6-di-n-pentylaminofluoran, 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, 6-diethylamino-1,2-benzofluoran, 6-(N-ethyl-N-isobutylamino)-1,2-benzofluoran, 6-(N-ethyl-N-isopentylamino)-1,2-benzofluoran, 2-(3-methoxy-4-dodecoxystyryl)quinoline, 2-diethylamino-8-diethylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidin-5,1′(3′H)-isobenzofuran]-3′-one, 2-di-n-butylamino-8-di-n-butylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidin-5,1′(3′H)-isobenzofuran]-3′-one, 2-di-n-butylamino-8-diethylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidin-5,1′(3′H)-isobenzofuran]-3′-one, 2-di-n-butylamino-8-(N-ethyl-N-isoamylamino)-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidin-5,1′(3′H)-isobenzofuran]-3′-one, 2-di-n-butylamino-8-di-n-pentylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidin-5,1′(3′H)-isobenzofuran]-3′-one, 4,5,6,7-tetrachloro-3-(4-dimethylamino-2-methoxyphenyl)-3-(1-n-butyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-tetrachloro-3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-tetrachloro-3-(4-diethylamino-2-ethoxyphenyl)-3-(1-n-pentyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone, 4,5,6,7-tetrachloro-3-(4-diethylamino-2-methylphenyl)-3-(1-ethyl-2-methylindol-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, 2,6-bis(2,4-diethyloxyphenyl)-4-[4-bis(4-methyloxyphenyl)aminophenyl]pyridine, 2-(4′-dimethylaminophenyl)-4-methoxyquinazoline, 4,4'-Ethylenedioxy-bis[2-(4-diethylaminophenyl)quinazoline]

[0015] In addition, fluorans may be compounds having a substituent on the phenyl group forming the xanthene ring, or may be compounds that have a substituent on the phenyl group forming the xanthene ring and also have a substituent on the phenyl group forming the lactone ring (for example, an alkyl group such as a methyl group, or a halogen atom such as a chlorine atom), and that exhibit a blue or black color.

[0016] Component (b), ie, the electron accepting compound, is a compound that accepts electrons from component (a) and functions as a developer for component (a). Component (b) is a compound represented by the following formula (B):

[0017] The compound represented by formula (B) is as follows: [ka] (In the formula, X is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogen atom; Y is an alkyl group having 1 to 6 carbon atoms.

[0018] Regarding X, Examples of the alkyl group having 1 to 3 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, n-propyl, and isopropyl groups, and preferably methyl or ethyl groups. Examples of the alkoxy group having 1 to 3 carbon atoms include linear or branched alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, and an isopropoxy group. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with chlorine atoms being preferred. The substitution position of X is not particularly limited, but is preferably the 4-position (para-position) of the benzene ring.

[0019] Regarding Y, Examples of the alkyl group having 1 to 6 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups. Preferred are alkyl groups having 2 to 4 carbon atoms (more preferably n-propyl or n-butyl groups).

[0020] Specific examples of (B) include the following: N-phenylsulfonyl-N′-methylurea, N-phenylsulfonyl-N′-ethylurea, Np-tolylsulfonyl-N′-n-propylurea, Np-tolylsulfonyl-N′-n-butylurea, Np-tolylsulfonyl-N′-tert-butylurea, Np-ethylphenylsulfonyl-N′-n-hexylurea, Np-methoxyphenylsulfonyl-N′-ethylurea, Npn-propoxyphenylsulfonyl-N′-n-propylurea, Np-chlorophenylsulfonyl-N′-ethylurea, Nm-chlorophenylsulfonyl-N′-n-propylurea, Np-chlorophenylsulfonyl-N′-n-propylurea, Np-Bromophenylsulfonyl-N'-n-butylurea

[0021] The compound represented by formula (B) is preferably a compound in which X is a methyl group, an ethyl group, or a halogen atom and is located at the 4-position (para-position) of the benzene ring, and Y is an alkyl group having 2 to 4 carbon atoms. More preferred are compounds in which X is a methyl group or a chlorine atom and is located at the 4-position (para-position) of the benzene ring, and Y is an n-propyl group or an n-butyl group.

[0022] The component (ii) may be a compound represented by formula (B) further containing a conventionally known component (ii).

[0023] Conventionally known electron-accepting compounds include compounds selected from a group of compounds having an active proton, a group of pseudo-acidic compounds (a group of compounds that are not acids but act as an acid in the reversible thermochromic composition to cause component (A) to develop color), and a group of compounds having an electron vacancy.

[0024] Examples of compounds having an active proton include compounds having a phenolic hydroxyl group and derivatives thereof, carboxylic acids and derivatives thereof, acidic phosphate esters and derivatives thereof, azole compounds and derivatives thereof, 1,2,3-triazole and derivatives thereof, cyclic carbosulfimides, halohydrins having 2 to 5 carbon atoms, sulfonic acids and derivatives thereof, and inorganic acids. Preferred examples of the carboxylic acids and derivatives thereof include aromatic carboxylic acids and derivatives thereof, and aliphatic carboxylic acids having 2 to 5 carbon atoms and derivatives thereof. Examples of the pseudo-acidic compounds include metal salts of compounds having a phenolic hydroxyl group, metal salts of carboxylic acids, metal salts of acidic phosphate esters, metal salts of sulfonic acids, aromatic carboxylic acid anhydrides, aliphatic carboxylic acid anhydrides, mixed anhydrides of aromatic carboxylic acids and sulfonic acids, cycloolefin dicarboxylic acid anhydrides, urea and its derivatives, thiourea and its derivatives, guanidine and its derivatives, and halogenated alcohols. Compounds having electron vacancies include borates, borate esters, and inorganic salts.

[0025] Compounds having a phenolic hydroxyl group include a wide range of compounds, from monophenol compounds to polyphenol compounds, and further include bisphenol compounds, trisphenol compounds, phenol-aldehyde condensation resins, etc. The compound having a phenolic hydroxyl group preferably has at least two benzene rings. In addition, the compound having a phenolic hydroxyl group may have a substituent such as an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group, a carboxyl group and its ester or amide group, or a halogen atom.

[0026] Examples of metals contained in metal salts of compounds having a phenolic hydroxyl group include sodium, potassium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, lead, and molybdenum.

[0027] Specific examples of conventionally known electron-accepting compounds include phenol, o-cresol, 4-np-nonylphenol, 4-n-octylphenol, 4-n-dodecylphenol, 4-n-stearylphenol, 4-chlorophenol, 4-bromophenol, 2-phenylphenol, n-butyl 4-hydroxybenzoate, n-octyl 4-hydroxybenzoate, resorcinol, 4-tert-butylcatechol, 2,4-dihydroxy-4′-tert-butylbenzophenone, dodecyl gallate, 1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,3-bis(4-hydroxyphenyl)ethane, 1,4-bis(4-hydroxyphenyl)ethane, 1,5-bis(4-hydroxyphenyl)ethane, 1,6-bis(4-hydroxyphenyl)ethane, 1,7-bis(4-hydroxyphenyl)ethane, 1,8-bis(4-hydroxyphenyl)ethane, 1,9-bis(4-hydroxyphenyl)ethane, 1,9-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,3-bis(4-hydroxyphenyl)ethane, 1,4-bis(4-hydroxyphenyl)ethane, 1,5-bis(4-hydroxyphenyl)ethane, 1,5-bis(4-hydroxyphenyl)ethane, 1,6-bis(4-hydroxyphenyl)ethane, 1,7-bis(4-hydroxyphenyl)ethane, 1,8-bis(4-hydroxyphenyl)ethane, 1,9-bis(4-hydroxyphenyl)ethane, 1,5 ... ,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)ethyl propionate, 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, 2,2-bis(4-hydroxy-3-methylphenyl)butane, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,3-bis[2- (4-hydroxyphenyl)-2-propyl]benzene, bis(2-hydroxyphenyl)methane, 4,4'-dihydroxydiphenyl sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone, bis(4-hydroxyphenyl)sulfide, 1,1,1-tris(4-hydroxyphenyl)ethane, 4,4'-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bisphenol, 4,4'-[4-(4-hydroxyphenyl)-sec-butylidene]bis(2-methylphenol),

[0028] The component (c) of the reaction medium that reversibly induces an electron transfer reaction between the components (a) and (b) in a specific temperature range will now be described. Examples of the component (c) include alcohols, esters, ketones, ethers, and acid amides. When the reversible thermochromic composition of the present invention is applied to microencapsulation and secondary processing, compounds having a carbon number of 10 or more are preferably used in order to stably retain them in the capsules, since low molecular weight compounds will evaporate out of the capsules when subjected to high heat treatment.

[0029] As the alcohols, aliphatic monohydric saturated alcohols having 10 or more carbon atoms are effective, and examples thereof include decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, eicosyl alcohol, and docosyl alcohol.

[0030] As the esters, esters having 10 or more carbon atoms are effective, and examples thereof include esters obtained from any combination of a monocarboxylic acid having an aliphatic and alicyclic or aromatic ring and a monohydric alcohol having an aliphatic and alicyclic or aromatic ring, esters obtained from any combination of a polycarboxylic acid having an aliphatic and alicyclic or aromatic ring and a monohydric alcohol having an aliphatic and alicyclic or aromatic ring, and esters obtained from any combination of a monocarboxylic acid having an aliphatic and alicyclic or aromatic ring and a polyhydric alcohol having an aliphatic and alicyclic or aromatic ring. Examples of esters include esters obtained by combining ethyl caprylate, octyl caprylate, stearyl caprylate, myristyl caprate, docosyl caprate, 2-ethylhexyl laurate, n-decyl laurate, 3-methylbutyl myristate, cetyl myristate, isopropyl palmitate, neopentyl palmitate, nonyl palmitate, cyclohexyl palmitate, n-butyl stearate, 2-methylbutyl stearate, 3,5,5-trimethylhexyl stearate, stearyl stea ... n-Undecyl Phosphate, Pentadecyl Stearate, Stearyl Stearate, Cyclohexylmethyl Stearate, Isopropyl Behenate, Hexyl Behenate, Lauryl Behenate, Behenyl Behenate, Cetyl Benzoate, Stearyl 4-tert-Butylbenzoate, Dimyristyl Phthalate, Distearyl Phthalate, Dimyristyl Oxalate, Dicetyl Oxalate, Dicetyl Malonate, Dilauryl Succinate, Dilauryl Glutarate, Diundecyl Adipate, Dilauryl Azelaate, Di-(n-Nonyl) Sebacate, Examples include 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, and xylene glycol distearate.

[0031] 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. Examples of the ester compounds include 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, laurate, 1-ethylpropyl hydroxypropyl ester ... 1-Ethylhexyl phosphate, 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-ethyl caproate pentyl palmitate, 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 behenate Examples include 3,7-dimethyloctyl erucate, 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-bromostearate, isostearyl 2-ketomyristate, 2-ethylhexyl 2-fluoromyristate, cetyl butyrate, stearyl butyrate, and behenyl butyrate.

[0032] Furthermore, in order to cause a color change that exhibits large hysteresis characteristics in the color density-temperature curve and to impart color memory properties that depend on temperature changes, exemplified are carboxylic acid ester compounds that exhibit a ΔT value (melting point-cloud point) of 5°C or more and less than 50°C, as described in Japanese Patent Publication No. 4-17154, 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, and the like.

[0033] Also effective are fatty acid ester compounds obtained from an odd-numbered aliphatic monohydric alcohol having 9 or more carbon atoms and an even-numbered aliphatic carboxylic acid, 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. Examples of the fatty acid ester compounds include 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, Examples include ethyl, 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-undecyl eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate, n-nonyl behenate, n-undecyl behenate, n-tridecyl behenate, and n-pentadecyl behenate.

[0034] 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 ... Examples of acetophenone include 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, and cyclopentyl phenyl ketone.

[0035] 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.

[0036] 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 N-methyl caproate. amide, 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, stearate 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, 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, trilauric acid amide Rimyristic 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 include adipic acid N-butylamide, glutaric acid N-butylamide, malonic acid N-butylamide, adipic acid N-octylamide, and adipic acid N-dodecylamide.

[0037] Furthermore, the component (iii) may be a compound represented by the following formula (1). [ka] [wherein 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 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, or a halogen atom, and r and p each independently represent an integer of 1 to 3. Among the compounds represented by formula (1), when R1 is a hydrogen atom, a reversible thermochromic composition having a wider hysteresis width can be obtained, which is preferable, and it is even more preferable that R1 is a hydrogen atom and m is 0. Among the compounds represented by formula (1), the compound represented by the following formula (2) is more preferred. [ka] (wherein 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). Examples of the compound represented by formula (2) 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.

[0038] Furthermore, the component (iii) may be a compound represented by the following formula (3). [ka] (In the formula, R represents an alkyl group or alkenyl group having 8 or more carbon atoms, m and n each independently represent an integer of 1 to 3, and X and Y each independently 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 atom.) Examples of the compound represented by formula (3) include diphenylmethyl octanoate, diphenylmethyl nonanoate, diphenylmethyl decanoate, diphenylmethyl undecanoate, diphenylmethyl dodecanoate, diphenylmethyl tridecanoate, diphenylmethyl tetradecanoate, diphenylmethyl pentadecanoate, diphenylmethyl hexadecanoate, diphenylmethyl heptadecanoate, and diphenylmethyl octadecanoate.

[0039] Furthermore, the component (iii) may be a compound represented by the following formula (4). [ka] (wherein 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 represented by formula (4) 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, a diester of glutaric acid and 2-(4-benzyloxyphenyl)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-(3-methylbenzyloxy)phenyl]ethanol, a diester of adipic acid and 2-(4-benzyloxyphenyl) ... Examples include the diester of suberic acid and 2-[4-(4-chlorobenzyloxy)phenyl]ethanol, the diester of suberic acid and 2-[4-(2,4-dichlorobenzyloxy)phenyl]ethanol, the diester of suberic acid and 2-[4-(2,4-dichlorobenzyloxy)phenyl]ethanol, the diester of azelaic acid and 2-(4-benzyloxyphenyl)ethanol, the diester of sebacic acid and 2-(4-benzyloxyphenyl)ethanol, the diester of 1,10-decanedicarboxylic acid and 2-(4-benzyloxyphenyl)ethanol, the diester of 1,18-octadecanedicarboxylic acid and 2-(4-benzyloxyphenyl)ethanol, and the diester of 1,18-octadecanedicarboxylic acid and 2-[4-(2-methylbenzyloxy)phenyl]ethanol.

[0040] Furthermore, the component (iii) may be a compound represented by the following formula (5). [ka] (wherein R represents an alkyl or alkenyl group having 1 to 21 carbon atoms, and n represents an integer of 1 to 3). Examples of the compound represented by formula (5) 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, and a diester of 1,4-bis(2-hydroxyethoxy)benzene and acetic acid. Examples of such esters include esters of 1,4-bis(2-hydroxyethoxy)benzene and propionic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and valeric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and caproic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and caprylic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and capric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and lauric acid, and diesters of 1,4-bis(2-hydroxyethoxy)benzene and myristic acid.

[0041] Furthermore, the component (iii) may be a compound represented by the following formula (6). [ka] (wherein 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 represented by formula (6) 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.

[0042] Furthermore, the component (iii) may be a compound represented by the following formula (7). [ka] (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; 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; and n represents 0 or 1.) Examples of the compound represented by formula (7) 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, and hexyl 4-biphenylacetate.

[0043] Furthermore, the component (iii) may be a compound represented by the following formula (8). [ka] (In the formula, R represents an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, or a halogen atom; Y represents 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 compound represented by formula (8) include phenoxyethyl 4-butoxybenzoate, phenoxyethyl 4-pentyloxybenzoate, phenoxyethyl 4-tetradecyloxybenzoate, esters of phenoxyethyl 4-hydroxybenzoate and dodecanoic acid, and dodecyl ether of phenoxyethyl vanillate.

[0044] Furthermore, the component (iii) may be a compound represented by the following formula (9). [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 represented by formula (9) include the benzoate ester of octyl 4-hydroxybenzoate, the benzoate ester of decyl 4-hydroxybenzoate, the 4-methoxybenzoate ester of heptyl 4-hydroxybenzoate, the 2-methoxybenzoate ester of dodecyl 4-hydroxybenzoate, and the benzoate ester of cyclohexylmethyl 4-hydroxybenzoate.

[0045] Furthermore, the component (iii) may be a compound represented by the following formula (10). [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 represented by formula (10) include phenoxyethyl ether of nonyl 4-hydroxybenzoate, phenoxyethyl ether of decyl 4-hydroxybenzoate, phenoxyethyl ether of undecyl 4-hydroxybenzoate, and phenoxyethyl ether of dodecyl vanillate.

[0046] Furthermore, the component (iii) may be a compound represented by the following formula (11). [ka] (wherein 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 represented by formula (11) 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.

[0047] Furthermore, the component (iii) may be a compound represented by the following formula (12). [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 represented by formula (12) include a diester of 4-phenylphenol ethylene glycol ether and cyclohexanecarboxylic acid, a diester of 4-phenylphenol diethylene glycol ether and lauric acid, a diester of 4-phenylphenol triethylene glycol ether and cyclohexanecarboxylic 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.

[0048] The reversible thermochromic composition of the present invention, which uses the compound represented by formula (B) as component (b), is unlikely to lose its reversible thermochromic function, even when subjected to repeated temperature changes, by becoming discolored in a temperature range above the high-side discoloration point (complete discoloration temperature) and becoming colored in a temperature range below the low-side discoloration point (complete color development temperature), and the density of the colored state and the density of the discolored state are unlikely to change even when used repeatedly.

[0049] The reversible thermochromic composition of the present invention is a compatible solution containing the above-mentioned components (A), (B), and (C) as essential components. The ratio of each component depends on the concentration, color change temperature, color change form, and type of each component, but generally, the component ratio that achieves the desired properties is 1:1 of component (A): 0.1 to 100, preferably 0.1 to 50, more preferably 0.5 to 20, of component (B), and 1 to 800, preferably 5 to 200, more preferably 5 to 100, and even more preferably 10 to 100 of component (C) (all ratios are in parts by mass). When the mass ratio of components (A), (B), and (C) is within the above range, the reversible thermochromic composition is likely to exhibit a high color density and tend to retain less color in the decolorized state, i.e., it is easy to obtain a reversible thermochromic composition with even better contrast between the colored state and the decolorized state.

[0050] The reversible thermochromic composition may contain various light stabilizers as required. The light stabilizer is contained to prevent photodegradation of the reversible thermochromic composition consisting of components (A), (B), and (C). The component ratio that achieves the desired properties is 0.3 to 24 parts, preferably 0.3 to 16 parts, of light stabilizer per 1 part of component (A) (all ratios are in parts by mass). Among the light stabilizers, the ultraviolet absorber effectively blocks ultraviolet rays contained in sunlight and prevents photodegradation caused by the excited state due to the photoreaction of component (A). Furthermore, antioxidants, singlet oxygen quenchers, superoxide anion quenchers, ozone quenchers, etc. suppress photooxidation reactions. The light stabilizers may be used alone or in a suitable mixture of two or more.

[0051] The reversible thermochromic composition of the present invention is effective when used as is, but can also be encapsulated in microcapsules to form a reversible thermochromic microcapsule pigment (hereinafter sometimes referred to as a "microcapsule pigment"), or dispersed in a thermoplastic resin or a thermosetting resin to form reversible thermochromic resin particles (hereinafter sometimes referred to as "resin particles"). The reversible thermochromic composition is preferably encapsulated in microcapsules to form a reversible thermochromic microcapsule pigment, because encapsulation in microcapsules makes it possible to form a chemically and physically stable pigment, and furthermore, the reversible thermochromic composition can maintain the same composition under various conditions of use, thereby achieving the same effects. Microencapsulation can be performed by any of the conventionally known methods, such as isocyanate-based interfacial polymerization, melamine-formalin-based or other in situ polymerization, liquid curing coating, phase separation from an aqueous solution, phase separation from an organic solvent, melt-dispersion cooling, air suspension coating, and spray drying, and is selected appropriately depending on the application. Furthermore, a secondary resin film can be provided on the surface of the microcapsules depending on the purpose to impart durability or modify the surface properties for practical use. The reversible thermochromic microcapsule pigment preferably has a mass ratio of inclusions to wall film of 7:1 to 1:1, and by having the mass ratio of inclusions to wall film within the above range, a decrease in color density and vividness during color development is prevented. A mass ratio of inclusions to wall film of 6:1 to 1:1 is more preferable.

[0052] The average particle size of the reversible thermochromic microencapsulated pigment or resin particles is preferably 0.01 to 50 μm, more preferably 0.1 to 30 μm, and even more preferably 0.5 to 20 μm. If the average particle size of the microencapsulated pigment or resin particles exceeds 50 μm, dispersion stability and processability are poor when blended into ink, paint, or resin. On the other hand, if the average particle size is less than 0.01 μm, it becomes difficult to achieve high-concentration color development. When the microencapsulated pigment or resin particles are used in inks for writing instruments, the average particle size is preferably 0.01 to 5 μm, more preferably 0.05 to 4 μm, even more preferably 0.1 to 3 μm, and particularly preferably 0.5 to 3 μm. If the average particle size of the microencapsulated pigment or resin particles exceeds 5 μm, it becomes difficult to obtain good ink dischargeability when used in writing instruments. On the other hand, if the average particle size is less than 0.01 μm, it becomes difficult to achieve high-density color development. The average particle diameter was measured by determining the particle area using image analysis particle size distribution measurement software (manufactured by Mountec Co., Ltd., product name: MacView), calculating the diameter equivalent to a circle with a projected area (Heywood diameter) from the area of ​​the particle area, and measuring the average particle diameter of particles equivalent to a sphere of equal volume using this value. If the particle size of all or most of the particles exceeds 0.2 μm, it is also possible to measure the average particle size of particles equivalent to an equal volume sphere using the Coulter method using a particle size distribution analyzer (Beckman Coulter, Inc., product name: Multisizer 4e). Furthermore, the volumetric particle size and average particle size may be measured using a calibrated laser diffraction / scattering particle size distribution analyzer (manufactured by HORIBA, Ltd., product name: LA-300) based on values ​​measured using the above software or a measuring device using the Coulter method.

[0053] A reversible thermochromic colorant such as a reversible thermochromic composition, a reversible thermochromic microcapsule pigment, or a reversible thermochromic resin particle is dispersed in a vehicle containing water and / or an organic solvent and, if necessary, various additives to form an ink composition (hereinafter, sometimes referred to as "ink"). It can be used as a reversible thermochromic liquid composition such as printing ink used in screen printing, offset printing, process printing, gravure printing, coater printing, pad printing, etc.; paint used in brush coating, spray coating, electrostatic coating, electrodeposition coating, flow coating, roller coating, dip coating, etc.; inkjet ink; ultraviolet-curing ink; ink for writing instruments such as marking pens, ballpoint pens, fountain pens, and brush pens; ink for applicators; ink for stamps; paints; cosmetics; and coloring liquids for textiles.

[0054] The reversible thermochromic liquid composition may contain various additives. Examples of additives include resins, crosslinking agents, curing agents, drying agents, plasticizers, viscosity modifiers, dispersants, ultraviolet absorbers, antioxidants, light stabilizers, anti-settling agents, smoothing agents, gelling agents, antifoaming agents, matting agents, penetrating agents, pH adjusters, foaming agents, coupling agents, moisturizing agents, antifungal agents, preservatives, and rust inhibitors.

[0055] Examples of the vehicle for a writing instrument used in the ink for a writing instrument include an oil-based vehicle containing an organic solvent, and an aqueous vehicle containing water and, if necessary, an organic solvent. When the vehicle is an aqueous vehicle, the writing instrument ink may contain a water-soluble organic solvent that is compatible with water. The water-soluble organic solvent suppresses evaporation of water from the ink and prevents fluctuations in the specific gravity of the vehicle, maintaining good dispersion stability of the reversible thermochromic microencapsulated pigment, and stabilizing the structure of the polymer flocculant (described below) or the loose aggregates formed by the polymer flocculant and the dispersant. Examples of organic solvents include ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, thiodiethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, and N-methyl-2-pyrrolidone. The water-soluble organic solvent is preferably blended in an amount of 1 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 25% by mass, based on the total amount of ink. If the blending ratio of the water-soluble organic solvent exceeds 40% by mass, the ink viscosity tends to increase. On the other hand, if the blending ratio is less than 1% by mass, the effect of suppressing water evaporation becomes poor.

[0056] When the writing instrument ink contains a water-soluble organic solvent and the hysteresis width (ΔH) of the reversible thermochromic microencapsulated pigment blended into the writing instrument ink is large, the specific gravity of the microencapsulated pigment is greater than 1, and when adjusting the specific gravity of the vehicle, using a water-soluble organic solvent with a specific gravity greater than that of water makes it easier to adjust the specific gravity. Therefore, it is preferable to use glycerin or the like with a specific gravity greater than 1.1 as the water-soluble organic solvent.

[0057] Writing instrument inks can be formulated with shear thinning agents, and inks containing shear thinning agents (shear thinning inks) can suppress aggregation and sedimentation of microencapsulated pigments and can also suppress bleeding of handwriting, resulting in the formation of good handwriting. Furthermore, when shear-thinning ink is stored in a ballpoint pen-shaped writing instrument, it can prevent ink leakage from the gap between the ball and the tip when the writing instrument is not in use, and can prevent ink from flowing back when the writing tip is left facing upward (upright).

[0058] Examples of shear thinning agents include xanthan gum, welan gum, succinoglycan (average molecular weight: about 1,000,000 to 8,000,000), which is an organic acid-modified heteropolysaccharide whose constituent monosaccharides are glucose and galactose, alka gum, guar gum, locust bean gum and derivatives thereof, hydroxyethyl cellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000 and containing alkyl esters of methacrylic acid as the main component, glucomannan, thickening polysaccharides having gelling ability extracted from seaweed such as agar and carrageenan, benzylidene sorbitol and benzylidene xylitol or derivatives thereof, cross-linked acrylic acid polymers, inorganic substances, and the like. Examples of surfactants include nonionic surfactants with an HLB value of 8 to 12, such as fine particles, polyglycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene castor oil, polyoxyethylene lanolin / lanonin alcohol / beeswax derivatives, polyoxyethylene alkyl ethers / polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, and fatty acid amides, salts of dialkyl or dialkenyl sulfosuccinic acid, mixtures of N-alkyl-2-pyrrolidone and anionic surfactants, and mixtures of polyvinyl alcohol and acrylic resins.

[0059] A polymer flocculant can be blended into the ink for writing instruments. In inks containing a polymer flocculant (flocculating ink), the microcapsule pigment forms loose aggregates via the polymer flocculant, preventing the microcapsule pigments from coming into contact with each other and aggregating, thereby improving the dispersibility of the microcapsule pigment.

[0060] Examples of polymer flocculants include polyvinylpyrrolidone, polyethylene oxide, and water-soluble polysaccharides. Examples of water-soluble polysaccharides include tragacanth gum, guar gum, pullulan, cyclodextrin, and water-soluble cellulose derivatives. Furthermore, examples of water-soluble cellulose derivatives include methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, and hydroxypropyl methyl cellulose. Among the above polymer flocculants, hydroxyethyl cellulose is preferred because of its excellent dispersibility. The polymer flocculant is preferably blended in an amount of 0.1 to 1 mass %, more preferably 0.3 to 0.5 mass %, based on the total amount of ink. By blending within this range, the microencapsulated pigment forms loose aggregates, and the effect of improving the dispersibility of the microencapsulated pigment can be fully exerted.

[0061] The dispersibility of the microcapsule pigment can be improved by blending a dispersant into the ink for the writing instrument. In addition, a polymer flocculant and a dispersant can be used in combination. When both are used in combination, the dispersibility of the microencapsulated pigment can be improved, and the dispersibility of the loose aggregates of the microencapsulated pigment formed via the polymer flocculant can be further improved.

[0062] Examples of dispersants include synthetic resins such as polyvinylpyrrolidone, polyvinyl butyral, polyvinyl ether, styrene-maleic acid copolymer, ketone resin, hydroxyethyl cellulose and its derivatives, and styrene-acrylic acid copolymer, acrylic polymers, PO·EO adducts, and polyester amine oligomers. Among the above dispersants, acrylic polymer dispersants are preferred because they have excellent dispersibility for microencapsulated pigments, acrylic polymer dispersants having carboxy groups are more preferred, and acrylic polymer dispersants having a comb structure and carboxy groups on the side chains are even more preferred. A particularly preferred dispersant is an acrylic polymer dispersant with a comb structure having multiple carboxy groups in the side chains, and a specific example is Solsperse 43000, a product name manufactured by Lubrizol Japan Co., Ltd. The dispersant is preferably blended in an amount of 0.01 to 2% by mass, more preferably 0.1 to 1.5% by mass, based on the total amount of ink. If the blending ratio of dispersant exceeds 2% by mass, the microencapsulated pigment is likely to settle or float when subjected to external vibrations, etc. On the other hand, if the blending ratio is less than 0.01% by mass, the effect of improving dispersibility is less likely to be achieved.

[0063] By blending a water-soluble resin into the ink for a writing instrument, it is possible to impart adhesion and viscosity to the handwriting on the paper surface. Examples of water-soluble resins include alkyd resins, acrylic resins, styrene-maleic acid copolymers, cellulose derivatives, polyvinylpyrrolidone, polyvinyl alcohol, and dextrin. Among the above-mentioned water-soluble resins, polyvinyl alcohol is preferred because it provides excellent stability to the acrylic polymer dispersant, and partially saponified polyvinyl alcohol with a saponification degree of 70 to 89 mol % is more preferred because it provides excellent solubility in the ink even in the acidic range. The water-soluble resin is preferably blended in an amount of 0.3 to 3 mass %, more preferably 0.5 to 1.5 mass %, based on the total amount of the ink.

[0064] When the viscosity of the vehicle used in the ink for a writing instrument is low, adding a specific gravity adjuster can prevent the microcapsule pigment from settling or floating up in the ink and becoming localized, thereby improving the dispersion stability of the microcapsule pigment. The dispersion stability of a microencapsulated pigment is maximized when the difference in specific gravity between the vehicle and the microencapsulated pigment is minimal, and the specific gravity adjuster brings the specific gravity of the vehicle closer to that of the microencapsulated pigment. The specific gravity of the vehicle depends on the specific gravity of the water-soluble substance dissolved in the vehicle and the amount added, so adding and dissolving a larger amount of a specific gravity adjuster with a larger specific gravity in the vehicle makes it possible to increase the specific gravity of the vehicle.

[0065] Examples of specific gravity adjusters include oxyacids of Group 6 elements having an atomic weight of 90 to 185 and salts thereof. Such a specific gravity adjuster can adjust the specific gravity of the vehicle to be closer to that of the microcapsule pigment, which has a higher specific gravity, and can prevent the microcapsule pigment from settling or floating up and becoming localized when subjected to external stimuli such as vibration, even while the ink has a low viscosity.

[0066] The oxygen acids and salts thereof are selected from the group consisting of oxygen acids of transition metal elements and salts thereof, and the oxygen acid ions thereof are said to form tetrahedrons or octahedrons in which oxygen atoms are usually 4- or 6-coordinated to metal atoms, etc. The oxygen acid and its salt may be a polyacid and its salt, i.e., a polyacid acid salt. The polyacid includes an isopolyacid, a heteropolyacid, etc., and the polyacid acid salt includes an isopolyacid acid salt, a heteropolyacid acid salt, etc.

[0067] Examples of the specific gravity adjuster include a single oxygen acid and its salt, an isopoly acid and its salt, and a heteropoly acid and its salt. Examples of the single oxygen acid include molybdic acid and tungstic acid, and examples of the salt of the single oxygen acid include sodium molybdate, potassium molybdate, ammonium molybdate, sodium tungstate, potassium tungstate, ammonium tungstate, lithium tungstate, and magnesium tungstate. Examples of isopolyacids include metamolybdic acid, paramolybdic acid, metatungstic acid, paratungstic acid, and isotungstic acid. Furthermore, examples of isopolyacid salts include sodium metamolybdate, potassium metamolybdate, ammonium metamolybdate, sodium paramolybdate, potassium paramolybdate, ammonium paramolybdate, sodium metatungstate, potassium metatungstate, ammonium metatungstate, barium metatungstate, sodium paratungstate, and sodium isotungstate. Examples of heteropolyacids include molybdophosphoric acid, molybdosilicic acid, tungstophosphoric acid, and tungstosilicic acid, and examples of heteropolyacid salts include sodium molybdophosphate, sodium molybdosilicate, sodium tungstophosphate, and sodium tungstosilicate. The above oxygen acids and salts thereof can be used singly or in a suitable mixture of two or more.

[0068] Among the above-mentioned specific gravity adjusters, metatungstic acid, paratungstic acid, sodium metatungstate, potassium metatungstate, ammonium metatungstate, barium metatungstate, sodium paratungstate, sodium isotungstate, tungstophosphoric acid, tungstosilicic acid, sodium tungstophosphate, and sodium tungstosilicate are preferred, and sodium isotungstate, sodium metatungstate, and sodium paratungstate are more preferred.

[0069] The above-mentioned sodium isotungstate, sodium metatungstate, and sodium paratungstate are not only highly safe but also have a high specific gravity themselves, so that a liquid with a high specific gravity can be easily prepared depending on the amount added, and are therefore preferably used.

[0070] The gravity adjuster is preferably blended in an amount of 2 to 20% by mass, more preferably 5 to 15% by mass, based on the total amount of ink. If the blending ratio of the gravity adjuster exceeds 20% by mass, the microcapsule pigment tends to aggregate. On the other hand, if the blending ratio is less than 2% by mass, the effect of adjusting the vehicle's specific gravity is reduced. The mass ratio of the microcapsule pigment to the specific gravity adjuster is preferably 1:0.05 to 1:4, more preferably 1:0.075 to 1:2, and even more preferably 1:0.1 to 1:1.5.

[0071] The vehicle containing the above-mentioned specific gravity adjuster is particularly effective for microencapsulated pigments with high specific gravities, and even though the ink has a low viscosity, it can suppress the sedimentation of the microencapsulated pigment in the ink when an external stimulus such as vibration is applied, thereby improving the dispersion stability of the microencapsulated pigment. The specific gravity of a microencapsulated pigment depends on the particle size, the components and their contents encapsulated in the microcapsules, the components and film thickness of the capsule wall membrane, the colored state of the microencapsulated pigment, and the temperature, but the specific gravity is preferably 1.05 to 1.20 when the microencapsulated pigment is in a fully colored state and is based on water at 20°C. Such microencapsulated pigments exhibit a large hysteresis width (ΔH), and can be decolorized by heating and retained in a decolorized state within a specific temperature range. However, microencapsulated pigments with a large hysteresis width (ΔH) often use a compound having two or more aromatic rings in the molecule as component (c), which tends to increase the specific gravity and cause them to settle and separate in the ink. The microencapsulated pigments are particularly prone to settling and separation when subjected to external stimuli such as vibration. However, in inks containing the above-mentioned specific gravity adjusters, the ink has a low viscosity, but the microcapsule pigment is prevented from settling and becoming localized, and the dispersion stability of the microcapsule pigment can be improved, so the specific gravity adjusters are preferably used. Considering the dispersion stability of the microencapsulated pigment in the ink, the specific gravity of the microencapsulated pigment, when the microencapsulated pigment is in a fully colored state and is based on water at 20°C, is preferably 1.10 to 1.20, and more preferably 1.12 to 1.15. The specific gravity of the microcapsule pigment can be measured by the following method.

[0072] (Method for measuring specific gravity of microcapsule pigments) 1. 30 ml of glycerin aqueous solution and 1 g of fully colored microcapsule pigment are placed in a screw cap bottle and mixed to obtain a microcapsule pigment dispersion. 2. 30 ml of the microcapsule pigment dispersion is adjusted to 20°C and centrifuged at 1000 rpm for 30 seconds. A refrigerated tabletop centrifuge (manufactured by Kokusan Co., Ltd., product name: H103N) can be used as the centrifuge. 3. Observe the microcapsule pigment dispersion. If most of the microcapsule pigment has settled to the bottom of the beaker, repeat steps 1 and 2 using an aqueous solution with a higher glycerin concentration than the glycerin aqueous solution used at this time, and observe the state of the dispersion. If it is confirmed that most of the microcapsule pigment is floating on the liquid surface, repeat steps 1 and 2 using an aqueous solution with a lower glycerin concentration than the glycerin aqueous solution used this time, and observe the state of the dispersion. The above series of operations is repeated until it is visually confirmed that the majority of the microencapsulated pigment does not float to the surface or settle, but that the glycerin aqueous solution is uniformly colored except for the surface and the area near the bottom of the screw cap bottle. When this state is observed, the specific gravity of the glycerin aqueous solution is measured and used as the specific gravity of the microencapsulated pigment. The specific gravity of the glycerin aqueous solution can be measured by the hydrometer method described in JIS K0061, Section 7.1, using an aqueous solution adjusted to 20°C.

[0073] Furthermore, the vehicle containing the above-mentioned specific gravity adjuster has a specific gravity in the range of 1.00 to 1.30 at 20°C when water is used as the reference substance, and the specific gravity is preferably 1.05 to 1.20, and more preferably 1.08 to 1.18. Furthermore, the specific gravity of the vehicle is preferably 0.90 to 1.20 times, and more preferably 0.95 to 1.10 times, the specific gravity of the microcapsulated pigment. When the specific gravity of the vehicle is within the above range and the ratio of the specific gravity of the vehicle to the specific gravity of the microencapsulated pigment is also within the above range, even when the ink is subjected to an external stimulus such as vibration, the microencapsulated pigment is further prevented from settling and becoming localized in the ink, even though the ink has a low viscosity, and the dispersion stability of the microencapsulated pigment can be further improved.

[0074] When the vehicle for the writing instrument is an aqueous vehicle, the vehicle contains at least water, which is preferably blended in an amount of 30 to 80% by mass, more preferably 40 to 70% by mass, based on the total amount of the ink.

[0075] When the writing instrument ink is used in a ballpoint pen, it is preferable to add to the ink a lubricant such as a higher fatty acid such as oleic acid, a nonionic surfactant having a long-chain alkyl group, a polyether-modified silicone oil, a thiophosphite triester such as thiophosphite tri(alkoxycarbonylmethyl ester) or thiophosphite tri(alkoxycarbonylethyl ester), a polyoxyethylene alkyl ether or polyoxyethylene alkylaryl ether phosphate monoester, a polyoxyethylene alkyl ether or polyoxyethylene alkylaryl ether phosphate diester, or a metal salt, ammonium salt, amine salt or alkanolamine salt thereof to prevent wear of the ball seat.

[0076] In addition, additives such as wetting agents, resins, resin particles, pH adjusters, rust inhibitors, surfactants, wetting agents, antifoaming agents, viscosity adjusters, preservatives, and antifungal agents can also be added as needed.

[0077] The microencapsulated pigment is preferably blended in an amount of 5 to 40% by mass, more preferably 10 to 40% by mass, and even more preferably 10 to 30% by mass, based on the total amount of the writing instrument ink. By blending the microencapsulated pigment in the above range, the desired color density can be obtained and a decrease in ink outflow properties can be prevented.

[0078] The ink composition of the present invention can be produced by any conventionally known method, specifically by mixing the required amounts of the above-mentioned components and stirring them with a stirrer such as a propeller stirrer, a homodisper, or a homomixer, or by dispersing them with a disperser such as a bead mill.

[0079] When the ink for a writing instrument according to the present invention is used in a ballpoint pen, its viscosity is measured at a rotation speed of 1 rpm (shear rate of 3.84 sec) in an environment of 20°C. -1 When measured under the conditions of 100 rpm (shear rate 384 sec), the viscosity is preferably 1 to 2000 mPa·s, more preferably 3 to 1500 mPa·s, and even more preferably 500 to 1000 mPa·s, because this can prevent the sedimentation or aggregation of the microcapsule pigment. -1 When measured under the conditions of (1), the viscosity is preferably 1 to 200 mPa·s, more preferably 10 to 100 mPa·s, and even more preferably 20 to 50 mPa·s, because this allows for good ink discharge from the pen tip of the ballpoint pen. By having the viscosity within the above range, it is possible to maintain high levels of dispersion stability of the microencapsulated pigment and free flow of the ink within the mechanism of the ballpoint pen. The viscosity was measured using a rheometer (TA Instruments, product name: Discovery HR-2, cone plate (diameter 40 mm, angle 1°)) at a rotation speed of 1 rpm (shear rate 3.84 sec) with the ink placed in a 20°C environment. -1 ), or rotation speed 100 rpm (shear rate 384 sec -1 ) are values ​​measured under the conditions.

[0080] When the writing instrument ink according to the present invention is used in a ballpoint pen, the surface tension thereof is preferably 20 to 50 mN / m, and more preferably 25 to 45 mN / m, in an environment of 20° C. Having a surface tension within the above range makes it easy to suppress bleeding of written lines and strike-through onto the paper surface, and also improves the wettability of the ink to the paper surface. The surface tension was measured using a surface tension measuring instrument (manufactured by Kyowa Interface Science Co., Ltd., product name: DY-300) by placing the ink in an environment of 20°C using a vertical plate method using a platinum plate.

[0081] When the writing instrument ink according to the present invention is used in a ballpoint pen, its pH is preferably from 3 to 10, and more preferably from 4 to 9. By keeping the pH within the above range, aggregation or sedimentation of the microencapsulated pigment contained in the ink can be suppressed at low temperatures. The pH was measured by placing the ink in an environment of 20°C using a pH meter (manufactured by DKK Toa Corporation, product name: IM-40S).

[0082] When the writing instrument ink according to the present invention is used in a marking pen, its viscosity, measured at 30 rpm in an environment of 20° C., is preferably 1 to 20 mPa·s, more preferably 1 to 10 mPa·s, and even more preferably 1 to 5 mPa·s. Having a viscosity within the above range can improve the fluidity of the ink and the dispersion stability of the microencapsulated pigment. The viscosity was measured by placing the ink in an environment of 20°C using a BL-type rotational viscometer (manufactured by Toki Sangyo Co., Ltd., product name: TVB-M type viscometer, L-type rotor).

[0083] When the writing instrument ink according to the present invention is used in a marking pen, the surface tension thereof is preferably 25 to 50 mN / m, more preferably 25 to 45 mN, and even more preferably 35 to 45 mN / m in an environment of 20° C. Having a surface tension within the above range makes it easy to suppress bleeding of written lines and strike-through onto the paper surface, and also improves the wettability of the ink to the paper surface. The surface tension was measured using a surface tension measuring instrument (manufactured by Kyowa Interface Science Co., Ltd., product name: DY-300) by placing the ink in an environment of 20°C and using a vertical plate method with a glass plate.

[0084] When the writing instrument ink according to the present invention is used in a marking pen, its pH is preferably from 3 to 8, more preferably from 4 to 7, and even more preferably from 5 to 6. By keeping the pH within the above range, aggregation or sedimentation of the microencapsulated pigment contained in the ink at low temperatures can be suppressed. The pH was measured by placing the ink in an environment of 20°C using a pH meter (manufactured by DKK Toa Corporation, product name: IM-40S).

[0085] The ink for the writing implement is contained in a writing implement having a pen tip and an ink filling mechanism. Examples of writing implements include ballpoint pens, marking pens, fountain pens, brush pens, calligraphy pens, and other various writing implements.

[0086] The pen tip of the writing implement is not particularly limited, and pen tips with various types of tips can be used. Among the various types of tips, examples of ballpoint pen tips include tips in which a ball is held in a ball holding portion formed by deforming the area near the tip of a metal pipe by pressing it inward from the outer surface, tips in which a ball is held in a ball holding portion formed by cutting a metal material with a drill or the like, tips in which a resin ball receiving seat is provided inside a metal or plastic tip, and tips in which the ball held in the tip is urged forward by a spring body. The material of the ballpoint pen tip and ball is not particularly limited, and examples thereof include cemented carbide (super hard), stainless steel, ruby, ceramic, resin, rubber, and the like. The diameter of the ball is preferably 0.1 to 3.0 mm, more preferably 0.2 to 2.0 mm, and even more preferably 0.3 to 1.0 mm. The ball may also be subjected to a surface treatment such as a DLC coating.

[0087] Examples of marking pen tips include conventional porous members with interconnected pores, such as resin-processed fibers, fused heat-fusible fibers, and felt, which have a porosity selected from a range of approximately 30 to 70%, or extrusion-molded synthetic resin bodies with multiple ink outlet holes extending in the axial direction, and one end of which can be processed into a shape suitable for the purpose, such as a bullet shape, a rectangle, or a chisel shape, for practical use.

[0088] Examples of fountain pen tips (pen bodies) include those made by cutting metal plates such as stainless steel plates or gold alloy plates into a tapered shape and then bending or curving them, or those made by molding resin into the shape of a pen tip. The pen body may also have a slit in the center or a ball at the tip.

[0089] The ink filling mechanism may be, for example, an ink reservoir or ink occlusion body that can be directly filled with ink for a writing instrument. The ink container may be a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, or nylon, or a metal tubular body, and the above-mentioned chip may be directly connected, or the ink container and chip may be connected via a connecting member. The ink occlusion body is a fiber bundle formed by bundling crimped fibers in the longitudinal direction, and is contained within a covering such as a plastic cylinder or film, with the porosity adjusted to a range of approximately 40 to 90%.

[0090] When filling a ballpoint pen with ink for a writing instrument, the structure and shape of the ballpoint pen itself are not particularly limited, and an example is a ballpoint pen that has an ink reservoir filled with shear-thinning ink inside the barrel, the ink reservoir communicating with a ballpoint pen tip having a ball attached to the tip, and further has a liquid plug tightly attached to the end face of the ink to prevent backflow.

[0091] The ink backflow preventive composition is filled into the ink reservoir at the rear end of the ink reservoir. The ink backflow preventive composition comprises a non-volatile liquid and / or a hardly-volatile liquid, examples of which include petrolatum, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefin, α-olefin oligomer or co-oligomer, dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, polyether-modified silicone oil, and fatty acid-modified silicone oil. The ink backflow preventive composition may be used alone or in a suitable mixture of two or more kinds.

[0092] It is preferable to add a thickener to the ink backflow preventive composition to thicken it to a suitable viscosity. Examples of thickeners include clay-based thickeners such as silica with a hydrophobic surface treatment, fine particle silica with a methylated surface, aluminum silicate, swellable mica, hydrophobically treated bentonite or montmorillonite, fatty acid metal soaps such as magnesium stearate, calcium stearate, aluminum stearate, and zinc stearate, dextrin-based compounds such as tribenzylidene sorbitol, fatty acid amides, amide-modified polyethylene wax, hydrogenated castor oil, and fatty acid dextrins, and cellulose-based compounds. Furthermore, the above-mentioned liquid ink backflow preventive composition and a solid ink backflow preventive composition can be used in combination.

[0093] The barrel itself can also be used as the ink filling mechanism, and an example of such a mechanism is a ballpoint pen in which ink is directly filled into the barrel and a ballpoint pen tip is attached to the front end of the barrel.

[0094] A ballpoint pen equipped with a ballpoint pen tip and an ink filling mechanism may further include an ink supply mechanism for supplying the ink filled in the ink filling mechanism to the pen tip.

[0095] The ink supply mechanism is not particularly limited, but examples include: (1) a mechanism that has an ink guide core made of a fiber bundle or the like as an ink flow rate regulator and supplies ink to the pen tip; (2) a mechanism that has a comb-shaped ink flow rate regulator and supplies ink to the pen tip through this; and (3) a mechanism that supplies ink to the pen tip via a pen core consisting of multiple disks arranged in parallel with comb-shaped intervals, with slit-shaped ink guide grooves that run vertically through the disks in the axial direction and wider ventilation grooves than the grooves, and an ink guide core that is arranged in the axial center to guide ink from the ink filling mechanism to the pen tip.

[0096] The material for the pen core is not particularly limited as long as it is a synthetic resin that can be injection molded into a structure in which multiple discs are arranged in a comb-like groove pattern. Examples of synthetic resins include general-purpose polycarbonate, polypropylene, polyethylene, and acrylonitrile-butadiene-styrene copolymer (ABS resin). In particular, acrylonitrile-butadiene-styrene copolymer (ABS resin) is preferably used because it has high moldability and is easy to obtain pen core performance.

[0097] When the ballpoint pen is provided with an ink supply mechanism, the ink occlusion body can be used as the ink filling mechanism in addition to the ink reservoir and barrel.

[0098] Specific examples of the configuration of a ballpoint pen that contains writing instrument ink include: (1) a ballpoint pen in which a ballpoint pen tip is connected to an ink container directly or via a connecting member, the writing instrument ink is filled, and a ballpoint pen refill formed by filling the end face of the ink with an ink backflow preventive body is contained in the barrel; (2) a ballpoint pen in which the barrel is directly filled with writing instrument ink and is provided with a mechanism for supplying ink to the pen tip by using a comb-shaped ink flow regulator or an ink guide core made of a fiber bundle or the like as an ink flow regulator; (3) a ballpoint pen in which the barrel is directly filled with writing instrument ink and is provided with a mechanism for supplying ink to the pen tip via the above-mentioned pen core; and (4) a ballpoint pen in which the barrel contains an ink occlusion body made of a fiber bundle impregnated with writing instrument ink and is provided with a mechanism for supplying ink to the pen tip by using an ink guide core made of a fiber bundle or the like as an ink flow regulator.

[0099] When filling a marking pen with ink for a writing instrument, the structure and shape of the marking pen itself are not particularly limited, and an example is a marking pen that has an ink reservoir filled with cohesive ink inside the barrel, and the ink reservoir is connected to the marking pen tip. The ink occluder may be directly connected to the marking pen tip, or the ink occluder and the marking pen tip may be connected via a connecting member.

[0100] The marking pen having the marking pen tip and the ink filling mechanism may further have an ink supply mechanism for supplying the ink filled in the ink filling mechanism to the pen tip.

[0101] The ink supply mechanism is not particularly limited, but examples include, in addition to the ink supply mechanism provided in the ballpoint pen described above, (4) a mechanism provided with an ink flow rate regulator using a valve mechanism, which supplies ink to the pen tip by opening the valve. The valve mechanism can be a conventional, general-purpose pumping type that opens when the tip is pressed, and is preferably set to a spring pressure that can be pressed and opened by the pressure of the writing pen.

[0102] When the marking pen is provided with an ink supply mechanism, the ink filling mechanism may be an ink reservoir that can be directly filled with writing instrument ink, in addition to the ink occlusion body described above. Also, the barrel itself may serve as the ink filling mechanism, and the writing instrument ink may be directly filled therein.

[0103] Specific configurations of marking pens that contain writing instrument ink include: (1) a marking pen in which an ink occlusion body made of a fiber bundle impregnated with writing instrument ink is contained in a barrel, and a marking pen tip made of a fiber processed body or a resin molded body with capillary gaps is connected to the barrel directly or via a connecting member so that the ink occlusion body and the tip are connected; (2) a marking pen in which the barrel is filled directly with writing instrument ink and is provided with a mechanism for supplying ink to the pen tip by using a comb-shaped ink flow regulator or an ink guide core made of a fiber bundle or the like as an ink flow regulator; and (3) a marking pen in which the writing instrument ink is directly contained in the barrel. Examples of such marking pens include (4) marking pens that are filled with ink and have a mechanism for supplying ink to the pen tip via the pen core, (5) marking pens that are equipped with a marking pen refill housed in a barrel, and that have a tip and an ink reservoir connected via a valve mechanism that opens when the tip is pressed, and that have writing instrument ink directly filled into the ink reservoir, and (6) marking pens that have a marking pen tip made of a fiber processed body or a resin molded body with a capillary gap formed in an ink reservoir that contains an ink reservoir made of a fiber bundle impregnated with writing instrument ink, and that are connected directly or via a connecting member so that the ink reservoir and the tip are connected.

[0104] The ballpoint pen or marking pen may have a removable ink cartridge structure. In this case, after the ink contained in the ink cartridge of the writing instrument is used up, the writing instrument can be used again by replacing it with a new ink cartridge. Ink cartridges include those that double as the barrel that constitutes the writing instrument when connected to the writing instrument body, and those that cover and protect the barrel (rear barrel) after being connected to the writing instrument body. In the latter case, the ink cartridge may be used alone, or may be one in which the writing instrument body and ink cartridge are connected in the writing instrument before use, or one that is stored in the barrel in a disconnected state so that the user of the writing instrument can connect the ink cartridge in the barrel when using it to start use.

[0105] When a ballpoint pen or marking pen is directly filled with writing instrument ink, it is preferable to incorporate an agitator such as an agitating ball for agitating the ink into the ink reservoir or barrel into which the ink is filled, in order to facilitate redispersion of the microcapsule pigment. Examples of the shape of the agitator include a spherical body and a rod-shaped body. The material of the agitator is not particularly limited, and examples thereof include metal, ceramic, resin, and glass.

[0106] It is preferable that writing instruments such as ballpoint pens or marking pens be provided with a cap that is attached to cover the writing tip (tip tip) or with a retraction mechanism that allows the writing tip to protrude and retract from the writing instrument body (barrel), which can prevent the writing tip from drying out and becoming unable to write, or from becoming contaminated or damaged. A writing instrument with a retractable mechanism can be any writing instrument that has a structure in which the writing tip is stored in a barrel exposed to the outside air and the writing tip protrudes from the barrel opening when the retractable mechanism is activated.For example, a writing instrument with a retractable mechanism (retractable writing instrument) can be made by producing the above-mentioned ballpoint pen refill or marking pen refill, storing the refill in a barrel, and configuring it so that the writing tip protrudes from the barrel opening when the retractable mechanism is activated. When a writing instrument is provided with a retractable mechanism, it can also be a composite type retractable writing instrument (retractable ballpoint pen or retractable marking pen) that contains multiple ballpoint pen refills or marking pen refills in the barrel, and in which the writing tip of one of the refills is made to retract from the barrel opening by activation of the retractable mechanism.

[0107] Examples of retraction mechanisms include: (1) a side-slide retraction mechanism in which an operating part (clip) that can move back and forth in the radial direction protrudes radially outward from the rear side wall of the barrel, and the writing tip is retracted from the front end opening of the barrel by sliding the operating part forward; (2) a rear-end knock retraction mechanism in which the operating part at the rear end of the barrel is pressed forward to cause the writing tip to retract from the front end opening of the barrel; (3) a side-knock retraction mechanism in which the operating part that protrudes from the outer surface of the barrel side wall is pressed radially inward to cause the writing tip to retract from the front end opening of the barrel; and (4) a rotary retraction mechanism in which the operating part at the rear of the barrel is rotated to cause the writing tip to retract from the front end opening of the barrel.

[0108] The shapes of ballpoint pens and marking pens are not limited to the configurations described above, and they may be equipped with tips of different shapes, or with pen tips that dispense ink of different colors, or they may be composite writing instruments (double-headed, retractable pen tip, etc.) that are equipped with tips of different shapes and dispense ink of different colors from each tip.

[0109] The handwriting obtained by writing on a surface to be written on using a writing instrument containing the above-mentioned ink for a writing instrument can be discolored by rubbing with a finger or by using a heating or cooling tool. Examples of the heating tool include an electrically heated discoloring tool equipped with a resistance heating element such as a PTC element, a heat discoloring tool filled with a medium such as hot water, a heat discoloring tool using steam or laser light, and the application of a hair dryer. However, friction members and friction bodies are preferred because they can change color in a simple manner. Examples of cooling devices include electrically operated thermochromic devices using a Peltier element, thermochromic devices filled with a refrigerant such as cold water or ice chips, refrigerants, refrigerators, freezers, and the like.

[0110] As the friction member and friction body, an elastic body such as an elastomer or a plastic foam, which has a high elastic feel and can generate appropriate friction and frictional heat when rubbed, is preferred, but plastic molded bodies, stone, wood, metal, cloth, etc. can also be used. Although a general eraser used for erasing pencil marks may be used to rub the marks, eraser dust is generated during the rubbing, and therefore the above-mentioned friction member and friction body which hardly generate eraser dust are preferably used. Examples of materials for the friction member and friction body include silicone resin, SEBS resin (styrene-ethylene-butadiene-styrene block copolymer), etc. Silicone resin tends to adhere to areas that have been erased by rubbing, and handwriting tends to be repelled when writing is repeated, so SEBS resin is more preferably used.

[0111] The friction member or friction body may be a separate component of any shape from the writing instrument, but by providing it in the writing instrument, the writing instrument can be made highly portable. Also, a writing instrument set can be obtained by combining a writing instrument with a friction member or friction body of any shape that is separate from the writing instrument.

[0112] In the case of a writing instrument with a cap, the location where the friction member or friction body is provided is not particularly limited. For example, the cap itself may be formed from a friction member, the barrel itself may be formed from a friction member, or if a clip is provided, the clip itself may be formed from a friction member, or the friction member or friction body may be provided at the tip (top) of the cap or the rear end of the barrel (the part where the writing tip is not provided), etc. When the writing implement is a retractable writing implement, the location where the friction member or friction body is provided is not particularly limited. For example, the barrel itself may be formed from a friction member, and if a clip is further provided, the clip itself may be formed from a friction member, or the friction member or friction body may be provided near the barrel opening, at the rear end of the barrel (the part where the writing tip is not provided), or at the knock portion.

[0113] The ink can also be used as a stamp ink. Water is used as the medium for the ink for stamping, but a water-soluble organic solvent can also be used if necessary. When a microcapsule pigment is used in a stamp ink, glycerin or propylene glycol is preferred among water-soluble organic solvents. The water-soluble organic solvent is preferably blended in an amount of 30 to 60% by mass, more preferably 30 to 55% by mass, and even more preferably 40 to 50% by mass, based on the total amount of the ink. By blending the water-soluble organic solvent in the above range, the ink will not dry out or absorb moisture, making it easier to obtain a clear print. If the blending ratio of the water-soluble organic solvent exceeds 60% by mass, the moisture absorption tends to increase, causing the printed image to bleed or become mottled, making it difficult to obtain a clear printed image. On the other hand, if the blending ratio is less than 30% by mass, the printed surface dries out, causing the printed image to fade, making it difficult to obtain a clear printed image.

[0114] An organic solvent can also be used as the medium. Examples of organic solvents include castor oil fatty acid alkyl esters, cellosolve-based solvents, alkylene glycol-based solvents, ester-based solvents, hydrocarbon-based solvents, halogenated hydrocarbon-based solvents, alcohol-based solvents, ether-based solvents, ketone-based solvents, propionic acid-based solvents, highly polar solvents, and mixed solvents thereof.

[0115] The ink for stamping may also contain a thickener. Among the thickeners, alkali-soluble acrylic emulsions are preferred. When an alkali-soluble acrylic emulsion is used as the thickener, the pH of the ink is preferably 6-11, more preferably 7-11, and even more preferably 7-10.

[0116] By adding a binder resin to the ink for stamping, it is possible to improve the adhesion of the printed image and adjust the viscosity of the ink. Examples of the binder resin include a resin emulsion, an alkali-soluble resin, and a water-soluble resin.

[0117] In addition, additives such as wetting agents, resins, resin particles, pH adjusters, rust inhibitors, surfactants, wetting agents, antifoaming agents, viscosity adjusters, preservatives, and antifungal agents can also be added as needed.

[0118] The microencapsulated pigment is preferably blended in the stamp ink in an amount of 10 to 40% by mass, more preferably 10 to 35% by mass, and even more preferably 10 to 30% by mass, based on the total amount of the ink. If the blending ratio of the microencapsulated pigment exceeds 40% by mass, the dispersion stability of the microencapsulated pigment in the ink tends to decrease. On the other hand, if the blending ratio is less than 10% by mass, the color density tends to decrease.

[0119] The above-mentioned ink for stamps can be used as ink for stamp pads and ink for stamps provided with a stamp material having continuous pores. For example, a stamp pad can be impregnated with ink to obtain a stamp pad that supplies ink to the printing surface of a stamp that comes into contact with it.Also, a stamp can be obtained by impregnating ink into a stamp material having continuous pores.

[0120] The stamp can form an image on various surfaces. Furthermore, the image formed by the stamp ink can be discolored by rubbing it with a finger or by applying the heating or cooling tool described above. The heating tool is preferably the friction member or friction body described above, since it can be discolored by a simple method.

[0121] The friction member or friction body may be a member of any shape that is separate from the stamp, but by providing it on the stamp, it can be made highly portable. Also, a stamp set can be obtained by combining a stamp with a friction member or friction body of any shape that is separate from the stamp.

[0122] When applying or printing the reversible thermochromic liquid composition, the material of the support is not particularly limited and all materials are effective, such as paper, synthetic paper, fiber, fabric, synthetic leather, leather, plastic, glass, ceramic material, metal, wood, stone, etc. The shape of the support is not limited to a flat surface, but may be uneven. A reversible thermochromic laminate (reversible thermochromic printed matter) can be obtained by providing a reversible thermochromic layer containing a reversible thermochromic colorant on a support. In the case where a non-thermochromic colored layer (non-thermochromic image) is pre-formed on the support, the colored layer or image can be made to appear or disappear by the reversible thermochromic layer due to a change in temperature, further diversifying the manner of change.

[0123] The reversible thermochromic colorant can be melt-blended with an excipient and molded to form a reversible thermochromic solid molded article for application, which can be used as a solid writing material or a solid cosmetic. Examples of solid writing materials include crayons, pencil leads, mechanical pencil leads, solid gel markers, and the like. Examples of solid cosmetics include foundation, eyeliner, eyebrow pencil, eyeshadow, lipstick, etc.

[0124] Examples of excipients used in solid writing materials include waxes, gelling agents, clay minerals, and the like. Among the excipients, it is preferable to contain at least one of polyolefin wax, sucrose fatty acid ester, and dextrin fatty acid ester, as these are likely to improve the density of the writing.

[0125] In order to provide a solid writing material with excellent mechanical strength and thermal discoloration properties, and to facilitate handling during production, the excipient preferably has a mass average molecular weight (Mw) of 2,000 to 50,000, more preferably 10,000 to 30,000, and more preferably a number average molecular weight (Mn) of 1,000 to 10,000. The weight average molecular weight and number average molecular weight are values ​​measured by gel permeation chromatography (GPC) using polystyrene as a standard.

[0126] The excipient is preferably blended in an amount of 0.2 to 70% by mass, more preferably 0.5 to 40% by mass, based on the total amount of the solid writing material. When the blending ratio of the excipient is within the above range, the shape of the solid writing material can be easily obtained, and the writing density of the solid writing material can easily be increased. If the blending ratio of the excipient exceeds 70% by mass, it becomes difficult to obtain a sufficient writing density, whereas if the blending ratio is less than 0.2% by mass, it becomes difficult to obtain a shape suitable for a writable core material.

[0127] By blending a filler into the solid writing material, it is possible to improve the strength of the solid writing material and adjust the writing feel. Among fillers, talc or calcium carbonate is preferred because it has excellent moldability and is less likely to impair thermochromic properties when a microcapsule pigment is used. The filler is preferably blended in the range of 10 to 65% by mass based on the total amount of the solid writing material. If the blending ratio of the filler exceeds 65% by mass, the color development and writing feel tend to deteriorate. On the other hand, if the blending ratio is less than 10% by mass, the strength of the solid writing material tends to deteriorate.

[0128] The strength of the solid writing material can be improved by blending a binder resin into the solid writing material. Among the binder resins, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, and polyvinyl alcohol are preferred, and molding stability can be improved by using these resins in combination with polyester polyol. The binder resin is preferably blended in the range of 0.5 to 5% by mass based on the total amount of the solid writing material.

[0129] By incorporating a hindered amine compound into the solid writing material, it is possible to make the afterimage of the erased portion of the writing surface less visible, thereby ensuring rewritability without impairing the appearance of the writing surface and improving marketability.

[0130] In addition, additives such as viscosity adjusters, antifungals, preservatives, antibacterial agents, UV inhibitors, antioxidants, lubricants, and fragrances may also be added as needed.

[0131] The solid writing material may be used alone as a writing material, or may be used as an inner core with an outer shell covering the outer periphery to form a core-sheath structure (double core). The shell may contain additives such as non-thermochromic colorants, antifungal agents, preservatives, antibacterial agents, ultraviolet absorbers, antioxidants, lubricants, and fragrances, if necessary.

[0132] The solid writing material can be used to write on various writing surfaces, and furthermore, since it uses a reversible thermochromic colorant, the handwriting written on the writing surface can be discolored by rubbing with a finger or by applying the heating or cooling tool described above. As the heating tool, the friction member and friction body described above are preferred because they can be discolored by a simple method.

[0133] The friction member or friction body may be a component of any shape that is separate from the solid writing body or the exterior of a solid writing implement in which the solid writing body is housed in an exterior container, but by providing it on the solid writing body or the exterior of a solid writing implement in which the solid writing body is housed in an exterior container, it can be made highly portable.Specific examples include a form in which the friction member is provided on an exterior in the shape of a pencil, crayon, or the like, made of wood or paper.Furthermore, a solid writing body set can be obtained by combining the solid writing body with a friction member or friction body of any shape that is separate from the solid writing body.

[0134] The reversible thermochromic colorant can be melt-blended with a thermoplastic resin, a thermosetting resin, wax, or the like to form pellets, powder, or a paste, and used as a reversible thermochromic molding resin composition. The above-mentioned reversible thermochromic molding resin composition can be subjected to general-purpose injection molding, extrusion molding, blow molding, cast molding or the like to obtain molded articles in the form of three-dimensional objects of any shape, films, sheets, plates, filaments, rods, pipes and the like. Furthermore, by melt-blending it with a thermoplastic resin, toner and powder coatings can be obtained.

[0135] In addition, by blending a non-thermochromic colorant such as a general dye or pigment into the above-mentioned reversibly thermochromic liquid composition, solid molding for coating, or resin composition for molding, the color change behavior from color (1) to color (2) is exhibited.

[0136] On the above-mentioned molded body or laminate, a layer containing a light stabilizer and / or a transparent metallic luster pigment can be laminated to improve light resistance, or a top coat layer can be provided to improve durability. Examples of light stabilizers include ultraviolet absorbers, antioxidants, singlet oxygen quenchers, superoxide anion quenchers, and ozone quenchers. Examples of transparent metallic luster pigments include pigments having a core material such as natural mica, synthetic mica, glass flakes, alumina, or transparent film flakes whose surface is coated with a metal oxide such as titanium oxide.

[0137] Specific examples of products using the reversible thermochromic composition and the microcapsule pigment or resin particles containing the same include the following. (1)Toys Dolls and animal-shaped toys, hair for dolls and animal-shaped toys, doll houses and furniture, clothes, doll accessories such as hats, bags, shoes, accessory toys, stuffed toys, drawing toys, toy picture books, puzzle toys such as jigsaw puzzles, building block toys, block toys, clay toys, fluid toys, tops, kites, musical instrument toys, cooking toys, gun toys, catching toys, background toys, toys imitating vehicles, animals, plants, buildings, food, etc. (2) Clothing Clothing such as T-shirts, sweatshirts, blouses, dresses, swimwear, raincoats, skiwear, footwear such as shoes and shoelaces, cloth accessories such as handkerchiefs, towels, wrapping cloths, gloves, ties, hats, scarves, mufflers, etc. (3) Indoor decorations Curtains, curtain strings, tablecloths, rugs, cushions, carpets, rugs, upholstery, seats, mats, picture frames, artificial flowers, photo frames, etc. (4) Furniture Bedding such as futons, pillows, mattresses, lighting fixtures, heating and cooling appliances, etc. (5) Ornaments Rings, bracelets, tiaras, earrings, hair clips, false nails, ribbons, scarves, watches, glasses, etc. (6) Stationery Writing implements, stamps, erasers, writing pads, rulers, notebooks, adhesive tape, etc. (7)Daily necessities Lipstick, eye shadow, foundation, eyeliner, eyebrow pencil, nail polish, hair dye, false nails, false nail paint, and other cosmetics, toothbrushes, etc. (8) Kitchen utensils Cups, plates, chopsticks, spoons, forks, pots, frying pans, etc. (9) Other Calendars, labels, cards, recording materials, various types of printed materials for preventing counterfeiting, picture books and other books, bags, packaging containers, embroidery thread, sports equipment, fishing tackle, coasters, musical instruments, hand warmers, ice packs, wallets and other bags, umbrellas, vehicles, buildings, temperature detection indicators, training tools, etc. [Example]

[0138] Examples are shown below. Unless otherwise specified, "parts" in the examples refer to "parts by mass."

[0139] Example 1 Preparation of reversible thermochromic composition As component (a), 1 part of 2-(3-trifluoromethylanilino)-6-di-n-pentylaminofluoran, as component (b), 2 parts of Np-tolylsulfonyl-N'-n-butylurea, as component (c), 5 parts of stearyl alcohol, 20 parts of cetyl alcohol, and 25 parts of stearyl laurate were mixed and dissolved by heating to obtain a reversible thermochromic composition that reversibly changes color from black to colorless. The above-mentioned reversible thermochromic composition had a reversible thermochromic function of becoming in a decolorized state at a temperature equal to or higher than the complete decolorization temperature t4 and in a colored state at a temperature equal to or lower than the complete color development temperature t1 even when the temperature was repeatedly changed.

[0140] Examples 2 to 8 Preparation of reversible thermochromic composition A reversible thermochromic composition was obtained in the same manner as in Example 1, except that the types and amounts of components (a), (b), and (c) were changed to those shown in Table 1 below. Each of the reversibly thermochromic compositions obtained reversibly changed from a colored state to a discolored state. The color change of each reversibly thermochromic composition is shown in Table 1. All of the above reversible thermochromic compositions had a reversible thermochromic function of becoming in a decolorized state at temperatures equal to or higher than t4 and in a colored state at temperatures equal to or lower than t1 even when the temperature was repeatedly changed.

[0141] [Table 1]

[0142] [Discoloration temperature measurement] Each of the reversible thermochromic compositions obtained in Examples 1 to 8 was filled into a transparent glass capillary tube with an inner diameter of 1 mm and a length of 78 mm to a height of about 10 mm from the bottom of the capillary tube to obtain a sample for measuring discoloration temperature. The entire portion of each color-change temperature measurement sample containing the reversible thermochromic composition was immersed in a transparent heat transfer liquid, and the color change state of the reversible thermochromic composition was visually observed while changing the temperature of the transparent heat transfer liquid. The complete color-changing temperature t1, color-changing onset temperature t2, color-fading onset temperature t3, and complete color-fading temperature t4 were measured, and ΔH [hysteresis width: (intermediate temperature between t3 and t4) - (intermediate temperature between t1 and t2)] was calculated. The results are shown in Table 2 below. The numbers in the table indicate "°C."

[0143] [Table 2]

[0144] Example 9 Preparation of reversible thermochromic microencapsulated pigments 6.5 parts of 2-(3-trifluoromethylanilino)-6-di-n-pentylaminofluoran as component (a), 10 parts of Np-tolylsulfonyl-N'-n-butylurea as component (b), and 50 parts of 4-benzyloxyphenylethyl caprate as component (c) were mixed and dissolved by heating to obtain a reversible thermochromic composition that reversibly changes color from black to colorless. This reversible thermochromic composition was added to a mixed solution consisting of 35 parts of aromatic isocyanate prepolymer as a wall material and 40 parts of a cosolvent, and then emulsified and dispersed in an 8% aqueous polyvinyl alcohol solution. After stirring while heating, 2.5 parts of a water-soluble aliphatic modified amine was added and stirring was continued to prepare a microcapsule dispersion. From the above microcapsule dispersion, a reversible thermochromic microcapsule pigment with an average particle size of 2.0 μm was obtained by centrifugation. The resulting microcapsule pigment reversibly changed color from black to colorless. Furthermore, the microcapsule pigment exhibited a reversible thermochromic function, in that it disappeared at temperatures above t4 and developed a color at temperatures below t1 even after repeated temperature changes.

[0145] Example 10 Preparation of reversible thermochromic microencapsulated pigments 6.5 parts of 2-(3-trifluoromethylanilino)-6-di-n-pentylaminofluoran as component (a), 10 parts of Np-chlorophenylsulfonyl-N'-n-propylurea as component (b), and 50 parts of 4-benzyloxyphenylethyl caprate as component (c) were mixed and dissolved by heating to obtain a reversible thermochromic composition that reversibly changes color from black to colorless. This reversible thermochromic composition was added to a mixed solution consisting of 35 parts of aromatic isocyanate prepolymer as a wall material and 40 parts of a cosolvent, and then emulsified and dispersed in an 8% aqueous polyvinyl alcohol solution. After stirring while heating, 2.5 parts of a water-soluble aliphatic modified amine was added and stirring was continued to prepare a microcapsule dispersion. From the above microcapsule dispersion, a reversible thermochromic microcapsule pigment with an average particle size of 2.0 μm was obtained by centrifugation. The resulting microcapsule pigment reversibly changed color from black to colorless. Furthermore, the microcapsule pigment exhibited a reversible thermochromic function, in that it disappeared at temperatures above t4 and developed a color at temperatures below t1 even after repeated temperature changes.

[0146] [Discoloration temperature measurement] A reversible thermochromic ink was prepared by mixing 40 parts of each of the microcapsule pigments obtained in Examples 9 and 10, 52 parts of an ethylene-vinyl acetate copolymer resin emulsion, 5 parts of a thickener, and 3 parts of a leveling agent. A solid pattern was screen-printed on high-quality paper using the ink to obtain a sample for measuring the discoloration temperature. Each discoloration temperature measurement sample was placed in the measurement section of a color difference meter (Tokyo Denshoku Co., Ltd., product name: TC-3600). The sample section was heated and cooled at a rate of 2°C / min. The brightness value was measured as the color density at each temperature, and a color density-temperature curve was created. t1, t2, t3, t4, and ΔH were calculated from the color density-temperature curve. The results are shown in Table 3 below. The values ​​in the table are in degrees Celsius.

[0147] [Table 3]

[0148] Application example 1 Fabrication of a reversible thermochromic toy (reversible thermochromic miniature car) Ten parts of the reversible thermochromic composition of Example 1 were added to an oil vehicle consisting of 20 parts of polyacrylic acid ester, 40 parts of xylene, and 30 parts of methyl isobutyl ketone, and the mixture was stirred and mixed for 20 minutes while heating at 70°C to prepare a reversible thermochromic liquid composition, which is a paint used in spray painting. The entire body of a white miniature car made by injection molding ABS resin as a support was spray painted with the above paint and dried to create a reversible thermochromic layer, producing a reversible thermochromic toy (reversible thermochromic miniature car). The reversible thermochromic toy was completely black at room temperature (25°C), but when immersed in warm water at 40°C, the reversible thermochromic layer disappeared, changing from black to white. When removed from the warm water, it turned black again in a room temperature (25°C) environment. This change could be repeated.

[0149] Application example 2 Fabrication of a doll toy with hair using reversible thermochromic composite fiber Five parts of the reversible thermochromic composition of Example 4, one part of a dispersant, 94 parts of nylon 12 with a melting point of 180°C, and 0.1 parts of a pink general pigment were melt-mixed in an extruder at 200°C to prepare a reversible thermochromic molding resin composition in pellet form for the core. The above pellets were fed into an extruder for forming the core, and nylon 12 natural pellets were fed into an extruder for forming the sheath. Using a composite fiber spinning device, the fibers were spun at 200°C through 18 nozzles so that the core:sheath volume ratio was 6:4, to prepare a reversible thermochromic composite fiber consisting of 18 single filaments with an outer diameter of 90 μm. Furthermore, the reversible thermochromic composite fiber was implanted in the head of a doll in a conventional manner to produce a doll toy with hair made of the reversible thermochromic composite fiber. The hair attached to the doll toy was completely black at room temperature (25°C), but when immersed in warm water at 40°C, the reversible thermochromic composite fiber lost its color, changing from black to pink. When removed from the warm water, it returned to black again in a room temperature (25°C) environment. This change could be repeated.

[0150] Application example 3 Preparation of a reversible thermochromic writing implement (reversible thermochromic ballpoint pen) A reversible thermochromic liquid composition for a writing instrument ink was prepared by mixing 25 parts of the microcapsule pigment of Example 9 (previously cooled to -25°C or below to develop a black color), 0.3 parts of a shear-thinning agent (xanthan gum), 10 parts of urea, 10 parts of glycerin, 0.5 parts of a nonionic penetrant (manufactured by San Nopco Ltd., product name: Nopco SW-WET-366), 0.1 parts of a modified silicone antifoaming agent (manufactured by San Nopco Ltd., product name: Nopco 8034), 0.5 parts of a phosphate ester surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., product name: Plysurf AL), 0.5 parts of a pH adjuster (triethanolamine), 0.2 parts of an antifungal agent (manufactured by Lonza Japan Co., Ltd., product name: Proxel XL-2), and 52.9 parts of water. The above-mentioned writing instrument ink was sucked and filled into an ink reservoir tube made of polypropylene pipe, and then connected to a ballpoint pen tip having a 0.5 mm diameter carbide ball at its tip via a resin holder. Next, a viscoelastic ink backflow preventive material (liquid stopper) mainly composed of polybutene was filled into the rear end of the ink reservoir tube to prepare a ballpoint pen refill. The above-mentioned refill was incorporated into the barrel to obtain a reversible thermochromic ballpoint pen (retractable reversible thermochromic ballpoint pen). The ballpoint pen has a tip attached to a ballpoint pen refill housed in a barrel exposed to the outside air, and the tip protrudes from the front opening of the barrel by operating a clip-shaped slide mechanism attached to the rear side wall of the barrel. SEBS resin is attached to the rear end of the barrel as a friction member. When the above ballpoint pen was used to write on a piece of paper to form black letters (handwriting), the handwriting was black at room temperature (25°C), and when the letters were rubbed with a friction member, the letters disappeared and became colorless, and this state could be maintained unless the paper was cooled to below -25°C. Furthermore, when the paper was placed in a freezer and cooled to below -25°C, the letters again turned black, and this color change behavior could be reproduced repeatedly.

[0151] Application example 4 Fabrication of reversible thermochromic stamps A reversible thermochromic liquid composition serving as a stamp ink was prepared by mixing 20 parts of the microcapsule pigment of Example 10 (previously cooled to -25°C or below to develop a black color), 50 parts of glycerin, 1.5 parts of an alkali-soluble acrylic emulsion (manufactured by Rohm and Haas Japan Co., Ltd., product name: Primal DR73), 0.9 parts of triethanolamine, 10 parts of a 50% aqueous solution of polyvinylpyrrolidone, 0.2 parts of a silicone-based antifoaming agent, 0.5 parts of a penetrating leveling agent, 0.2 parts of a preservative, and 16.7 parts of water. The above-mentioned stamp ink was impregnated into a stamp material with continuous pores, and the stamp material was fixed to the stamp base material so that the printing surface of the stamp material was exposed. A cap was then fitted to produce a reversible thermochromic stamp. The rear end of the stamp base material was fitted with SEBS resin as a friction member. When the above stamp was repeatedly pressed against the surface to be stamped (paper), the ink smoothly flowed out of the printing surface of the stamping material and transferred to the surface to be stamped, allowing for the continuous formation of clear prints without bleeding. The print was black at room temperature (25°C), and when rubbed with a friction member, the print faded to a colorless state, a state that could be maintained unless cooled to -25°C or below. Furthermore, when the paper surface was placed in a freezer and cooled to -25°C or below, the print again turned black, and this color change behavior could be reproduced repeatedly.

[0152] Application example 5 Preparation of a reversible thermochromic solid writing implement A mixture for the inner core was prepared by kneading 40 parts of the microcapsule pigment of Example 9, 35 parts of filler, 10 parts of an excipient (manufactured by Toyokuni Oil Mills, product name: HS Crysta 4100), 10 parts of an excipient (manufactured by Sanyo Chemical Industries, Ltd., product name: SANWAX 131-P), 2 parts of a styrene-acrylic acid copolymer, 2 parts of polyvinyl alcohol, and 1 part of a hindered amine light stabilizer in a kneader. Next, 69 parts of filler, 10 parts of a sucrose fatty acid ester, 10 parts of the excipient, and 10 parts of an ethylene-vinyl acetate copolymer were kneaded in a kneader to prepare a mixture for the outer shell. The above-mentioned kneaded material for the inner core was wrapped around the outer periphery of the kneaded material for the outer shell so that it would become the inner core, and compression-molded using a press to form a solid writing material with a core-sheath structure into an outer diameter of φ3 mm and a length of 60 mm (the inner core was φ2 mm and the outer shell thickness was 0.5 mm). Note that the above dimensions are set values, and a reversible thermochromic solid writing material was produced by cooling to -25°C after compression molding and returning to room temperature. The solid writing body was molded into a round outer barrel (wooden shaft) to obtain a pencil. Furthermore, a cylindrical friction body made of SEBS resin was fixed to the rear end of the pencil via a metal connecting member to produce a reversible thermochromic solid writing implement with a friction body (reversible thermochromic pencil with friction body). When the solid writing implement was used to write on paper to form black letters (handwriting), the handwriting was black at room temperature (25°C). When the letters were rubbed with the friction member, the letters faded and became colorless. This state could be maintained unless the paper was cooled to -25°C or below. Furthermore, when the paper was placed in a freezer and cooled to -25°C or below, the letters again turned black, a discoloration behavior that could be repeatedly reproduced.

[0153] Application example 6 Fabrication of a reversible thermochromic writing implement (reversible thermochromic marking pen) 23 parts of the microcapsule pigment of Example 10 (previously cooled to -25°C or below to develop a black color) was mixed with a polymer flocculant (hydroxyethyl cellulose) [manufactured by Dow Chemical Japan, product name: CELLOSIZE A reversible thermochromic liquid composition for a writing instrument ink was prepared by mixing 0.4 parts of an acrylic polymer dispersant (manufactured by Lubrizol Japan Corp., product name: Solsperse 43000), 0.4 parts of a preservative (sodium 2-pyridinethiol 1-oxide) (manufactured by Lonza Japan Co., Ltd., product name: Sodium Omadine), 0.2 parts of a preservative (sodium 2-iodo-2-propynyl N-butylcarbamate) (manufactured by Lonza Japan Co., Ltd., product name: Glykasil 2000), 30 parts of glycerin, 0.01 parts of an antifoaming agent, 0.03 parts of a pH adjuster (10% diluted phosphoric acid solution), and 45.76 parts of water in an aqueous vehicle. The ink reservoir, made of polyester sliver coated with a synthetic resin film, was impregnated with the above-mentioned writing instrument ink and housed in a barrel made of polypropylene resin. A resin-processed pen body (bullet-shaped) made of polyester fiber was attached to the tip of the barrel via a resin holder, and a cap was attached to produce a reversible thermochromic marking pen (cap-type reversible thermochromic marking pen). The rear end of the barrel was fitted with SEBS resin as a friction member. When the marking pen was used to write black letters (handwriting) on ​​a piece of paper, the handwriting was black at room temperature (25°C), and when the letters were rubbed with a friction member, the letters disappeared and became colorless, and this state could be maintained unless the paper was cooled to below -25°C. Furthermore, when the paper was placed in a freezer and cooled to below -25°C, the letters again showed a discoloration behavior, turning black, and this discoloration behavior could be reproduced repeatedly.

[0154] Application example 7 Preparation of reversible thermochromic laminate (reversible thermochromic recording material) A reversible thermochromic liquid composition for printing ink was prepared by uniformly mixing 40 parts of the microcapsule pigment of Example 9 in an aqueous vehicle consisting of 50 parts of a urethane resin emulsion, 3 parts of a leveling agent, and 1 part of a thickener. The above printing ink was solid-printed using a screen printing plate onto the surface of a transparent polyester film (25 μm thick) with an adhesive layer on the backside as a support, to a dry film thickness of approximately 15 μm, and then dried and cured to form a reversible thermochromic layer. A transparent protective layer containing epoxy acrylate oligomer, polyester acrylate oligomer, and acrylate monomer was then formed on top of this, and polymerized by ultraviolet irradiation to produce a reversible thermochromic laminate (reversible thermochromic recording material). The above recording material was then attached to a white polyester film (188 μm thick) as a substrate and used in practical applications as an information display card. The reversible thermochromic recording material was once cooled to -25°C or below to allow the reversible thermochromic layer to completely develop a black color, after which character information was printed using a thermal printer equipped with a thermal head. The recording material displayed clear white character information (cut-out characters) on a black background, and the white character information was visible as long as it was maintained at a temperature above -25°C and below 71°C. Furthermore, when the recording material was cooled to below -25°C, causing the reversible thermochromic layer to completely turn black, the white cut-out characters were no longer visible. From this state, white cut-out characters could be formed on the reversible thermochromic layer again using a thermal printer, and the recording material could be reused many times.

[0155] Application example 8 Preparation of reversible thermochromic printed material (reversible thermochromic T-shirt) A reversible thermochromic liquid composition serving as a printing ink was prepared by uniformly mixing 30 parts of the microcapsule pigment of Example 10 (previously cooled to -25°C or below to develop a black color) and 0.1 parts of a yellow general pigment in an aqueous vehicle consisting of 60 parts of an acrylic emulsion (solid content 45%), 0.2 parts of an antifoaming agent, 1 part of a viscosity modifier, and 8.8 parts of water. The above printing ink was printed onto a white T-shirt (made of cotton) as a support, using a 100-mesh screen to create a pattern of numerous stars. The ink was then dried and hardened to form a reversible thermochromic layer, producing a reversible thermochromic printed material (reversible thermochromic T-shirt). At room temperature (25°C), numerous black star patterns were visible on the surface of the T-shirt. When heated to 69°C or higher, the reversible thermochromic layer disappeared and the yellow star patterns became visible. When cooled to -25°C or lower, the black star patterns were again visible. This change could be repeated. Furthermore, by heating the T-shirt with an iron or other device, the star pattern on the surface of the T-shirt could be partially discolored, forming a pattern in which only the desired star pattern was discolored, allowing the T-shirt pattern to be freely changed. Furthermore, the discolored state could be maintained at room temperature (25°C), and after heating the entire T-shirt to over 69°C to completely discolor the star pattern, it was possible to cool it down to below -25°C and cause the black star pattern to reappear. [Explanation of symbols]

[0156] t1 full color temperature t2 color development start temperature t3 decolorization start temperature t4 complete color erasure temperature T1 complete decolorization temperature T2 decolorization start temperature T3 color development start temperature T4 full color temperature ΔH Hysteresis width

Claims

1. (a) an electron-donating color-forming organic compound; (b) a compound represented by the following formula (B) as an electron-accepting compound; (c) a reaction medium that causes a reversible electron transfer reaction between the (a) component and the (b) component in a specific temperature range; A reversible thermochromic composition comprising: 【Chemistry 1】 (In the formula, X is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogen atom; Y is an alkyl group having 1 to 6 carbon atoms.

2. 2. The reversible thermochromic composition according to claim 1, wherein X is any one of a methyl group, an ethyl group, and a halogen atom.

3. 3. The reversible thermochromic composition according to claim 1, wherein Y is an alkyl group having 2 to 4 carbon atoms.

4. The reversible thermochromic composition according to any one of claims 1 to 3, wherein the component (ii) is contained in an amount of 0.1 to 100 parts by mass and the component (iii) is contained in an amount of 1 to 800 parts by mass relative to 1 part by mass of the component (i).

5. A reversible thermochromic microcapsule pigment encapsulating the reversible thermochromic composition according to any one of claims 1 to 4.

6. A reversible thermochromic liquid composition comprising the reversible thermochromic microcapsule pigment according to claim 5 and a vehicle.

7. 7. The reversible thermochromic liquid composition according to claim 6, which is selected from the group consisting of printing ink, writing ink, applicator ink, stamp ink, inkjet ink, paint, ultraviolet curable ink, coloring material, cosmetics, and textile coloring liquid.

8. A writing implement containing the reversible thermochromic liquid composition according to claim 7.

9. 9. The writing implement according to claim 8, further comprising a friction member that discolors handwriting made with the writing implement due to frictional heat.

10. A reversibly thermochromic solid molding for coating, comprising the reversibly thermochromic microcapsule pigment according to claim 5 and an excipient.

11. The reversibly thermochromic solid molded article for application according to claim 10, which is a solid writing material or a solid cosmetic.

12. A reversible thermochromic molding resin composition comprising the reversible thermochromic microcapsule pigment according to claim 5 and a molding resin.

13. A reversibly thermochromic molded article obtained by molding the reversibly thermochromic molding resin composition according to claim 12.

14. A reversible thermochromic laminate comprising a support and a reversible thermochromic layer comprising the reversible thermochromic microcapsule pigment according to claim 5.

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