JPH054994B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermochromic material that reversibly changes color at a predetermined temperature. The applicant has previously proposed (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound that reacts with the compound to reversibly color the compound, and (c) a temperature at which the reaction occurs. A reversible thermochromic material consisting of a composition containing three components that determine the color change temperature (color change temperature) and control the sensitivity of color change.
44706, 44707, 44709, 44908, Unexamined Japanese Patent Publication 1973-
Nos. 105554, 51-31682, 54-58727, etc.), but the thermochromic material of the present invention further increases the degree of freedom in selecting the component (c). The thermochromic material of the present invention includes (a) an electron-donating color-forming organic compound, (b) a compound having a phenolic hydroxyl group and its metal salt, an aromatic carboxylic acid, and a carbon number of 2.
-5 aliphatic carboxylic acids and metal salts thereof,
Acidic phosphoric acid ester and its metal salt, 1,2,3
-Triazole and its derivatives, carbon number 2 to 5
one or more compounds selected from halohydrins and derivatives thereof, (c) one or more aliphatic carboxylic anhydrides, or one or more aliphatic carboxylic anhydrides and alcohol. As an essential component, one or more compounds selected from compounds, esters, ketones, ethers, acid amides, aliphatic carboxylic acids having 6 or more carbon atoms, thiols, sulfides, disulfides, and nitrile compounds are essential components. It consists of a composition containing as follows. The electron-donating color-forming organic compound of component (a) is diarylphthalides, polyarylcarbinols,
These are so-called leuco dyes such as leucouramines, acylouramines, arylauramines, rhodamine B lactams, indolines, spiropyrans, and fluorans. Examples of these compounds are shown below. Crystal violet lactone, malachite green lactone, Michler hydrol, crystal violet carbinol, malachite green carbinol, N-(2,3-dichlorophenyl)leucouramine, N-benzoyluramine, rhodamine B lactam, N-acetyl auramine, N-phenyl auramine, 2-(phenyliminoethylidene)-3,3-dimethylindoline, N-3,3-trimethylindolinobenzospiropyran, 8-methoxy-N-3,3 -Trimethylindolinobenzospiropyran, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-6-benzyloxyfluorane, 1,2-benz-6-diethylamino Fluoran, 3,6-di-P-toluidino-4,
5-dimethylfluorane-phenylhydrazide-
γ-lactam, 3-amino-5-methylfluorane, 2-methyl-3-amino-6-methyl-7-
Methylfluorane, 2,3-butylene-6-di-
n-butylaminofluorane, 3-diethylamino-7-anilinofluorane, 3-diethylamino-7-(para-toluidino)-fluorane, 7-acetamino-3-diethylaminofluorane, 2
-bromo-6-cyclohexylaminofluorane, 2,7-dichloro-3-methyl-6-n-butylaminofluorane, and the like. As a compound having a phenolic hydroxyl group,
There are monophenols to polyphenols,
Furthermore, as a substituent, an alkyl group, an aryl group,
Examples include acyl groups, alkoxycarbonyl groups, and halogens. Examples of these compounds are shown below. Tert-butylphenol, nonylphenol, dodecylphenol, styrene tate phenol, 2,2-methylenebis-(4-methyl-6-tert-butylphenol), α-
Naphthol, β-naphthol, hydroquinone monomethyl ether, guaiacol, eugenol, P-chlorophenol, P-bromophenol, O-chlorophenol, O-bromophenol, O-phenylphenol, P-phenylphenol, P-(P -chlorophenyl)-phenol, O-(O-chlorophenyl)-phenol, P
-Methyl oxybenzoate, ethyl P-oxybenzoate, propyl P-oxybenzoate, butyl P-oxybenzoate, octyl P-oxybenzoate,
Dodecyl P-oxybenzoate, 3-isopropylcatechol, P-tert-butylcatechol, 4,4-methylenediphenol, 4,4-thiobis-(6-tert-butyl-3-methylphenol), 1,1- Bis-(4-hydroxyphenyl)-cyclohexane, 4,4-butylidene-bis-(6-tert-butyl-3-methylphenol), bisphenol A, bisphenol S, 1,2-dioxynaphthalene, 2 ,3-
Dioxynaphthalene, chlorcatechol, bromocatechol, 2,4-dihydroxybenzophenone, phenolphthalein, O-cresolphthalein, methyl protocatechuate, ethyl protocatechuate, propyl protocatechuate,
Octyl protocatechuate, dodecyl protocatechuate, 2,4,6-trioxymethylbenzene, 2,3,4-trioxyethylbenzene,
Methyl gallate, ethyl gallate, propyl gallate, butyl gallate, hexyl gallate, octyl gallate, dodecyl gallate, cetyl gallate, stearyl gallate, 2,3,5-trioxynaphthalene, tannic acid, phenol There are resins, etc. Examples of metal salts of compounds having a phenolic hydroxyl group include sodium, potassium, lithium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, There are metal salts of lead, molybdenum, and other metals. Aromatic carboxylic acids and aliphatic carboxylic acids having 2 to 5 carbon atoms include maleic acid, fumaric acid, benzoic acid, toluic acid, P-tert-butylbenzoic acid, chlorobenzoic acid, bromobenzoic acid, ethoxybenzoic acid, gallic acid, naphthoic acid, phthalic acid,
naphthalene dicarboxylic acid, acetic acid, propionic acid,
Examples include butyric acid and valeric acid. Examples of carboxylic acid metal salts include metal salts of monocarboxylic acids to polycarboxylic acids. Examples of these compounds are shown below. Acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, behenic acid, crotonic acid, oleic acid, elaidic acid, linoleic acid, linolenic acid, monochlor Acetic acid, monobromoacetic acid, monofluoroacetic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, ricinoleic acid, 12-hydroxystearic acid, lactic acid, pyruvic acid, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, malic acid, Tartaric acid, citrusic acid, maleic acid, fumaric acid, naphthenic acid, benzoic acid, toluic acid, phenylacetic acid, P-tertiarybutylbenzoic acid, cinnamic acid,
Chlorbenzoic acid, bromobenzoic acid, ethoxybenzoic acid, mandelic acid, protocatechuic acid, vanillic acid, resorcinic acid, dioxybenzoic acid, dioxychlorobenzoic acid, gallic acid, naphthoic acid, hydroxynaphthoic acid, phthalic acid, monophthalic acid Sodium, potassium, lithium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, such as ethyl ester, naphthalene dicarboxylic acid, naphthalene dicarboxylic acid monomethyl ester, trimellitic acid, pyromellitic acid, etc.
There are metal salts of metals such as lead and molybdenum. Examples of the acidic phosphate ester compound include ester groups such as alkyl groups, branched alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, aryl groups, and derivatives thereof. Acidic phosphoric acid ester compounds include monoesters and diesters, and may also be mixtures thereof. In the following compounds, the mixture of monoester and diester is called acid phosphate. Examples of acidic phosphoric acid ester compounds are shown below. Methyl acid phosphate, ethyl acid phosphate, n-propyl acid phosphate, n-butyl acid phosphate, 2-ethylhexyl acid phosphate, n-octyl acid phosphate, isodecyl acid phosphate , n-decyl acid phosphate, lauryl acid phosphate, myristyl acid phosphate, cetyl acid phosphate,
stearyl acid phosphate, docosyl acid phosphate, oleyl acid phosphate, 2-chloroethyl acid phosphate,
2,3-dipromo-2,3-dichloropropyl acid phosphate, dichloropropyl acid phosphate, cyclohexyl acid phosphate, phenyl acid phosphate, O-tolyl acid phosphate, 2,3-xyl acid phosphate Ruacid phosphate, P-cumenyl acid phosphate, mesityl acid phosphate, 1-naphthyl acid phosphate, 2-naphthyl acid phosphate, 1-anthryl acid phosphate, benzyl acid phosphate ate, phenethyl acid phosphate, styryl acid phosphate, cinnamyl acid phosphate, trityl acid phosphate, phenyl methyl phosphate, phenylethyl phosphate, phenyl n-propyl phosphate, phenyl n-butyl phosphate, phenyl n-octyl phosphate, phenyl lauryl phosphate, phenyl cyclohexyl phosphate, phenyl (2,3-xylyl) phosphate, cyclohexyl stearyl phosphate, cyclohexyl cetyl phosphate, dimethyl phosphate,
Diethyl phosphate, di-n-propyl phosphate, di-n-butyl phosphate, di-n-hexyl phosphate, di(2-ethylhexyl) phosphate, di-n-decyl phosphate, dilauryl phosphate, dimyristyl phosphate, Dicetyl phosphate, distearyl phosphate, dibehenyl phosphate, diphenyl phosphate, dicyclohexyl phosphate, diO-
Tolyl phosphate, bis(diphenylmethyl)
Examples include phosphate, bis(triphenylmethyl) phosphate, di(2,3-xylyl) phosphate, dibenzyl phosphate, di(1-naphthyl) phosphate, and the like. As metal salts of acidic phosphate ester compounds,
The above compounds sodium, potassium, lithium,
Calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin,
There are metal salts of metals such as copper, iron, vanadium, titanium, lead, and molybdenum. Examples of triazole compounds include 1,2,3-triazole, 4(5)-hydroxy-1,2,3-triazole, 5(6)-methyl-1,2,3-benzotriazole, 5-chloro-1, 2,3-benzotriazole, 7-nitro-1,2,3-benzotriazole, 4-benzoylamino-1,2,
3-benzotriazole, 4-hydroxy-1,
2,3-benzotriazole, naphtho-1,2,
3-triazole, 5,5'-bis(1,2,3-
benzotriazole), 1,2,3-benzotriazole-4-sulfooctylamide, and the like. Specific examples of halohydrin and its derivatives are shown below. 2,2,2-trichloroethanol, 2,2,
2-tribromoethanol, 2,2,2-trifluoroethanol, 1,1,1-trichloro-2
-Methyl-2-propanol, 1,1,1-tribromo-2-methyl-2-propanol, 4,
4,4-tribromobutanol, 1,3-dipromo-2-propanol, 2,3-dipromo-1-
Propanol, 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol,
2,2-bis(bromomethyl)-3-bromo-1
-propanol, 2,2-bis(chloromethyl)
-3-chloro-1-propanol, 2,2-bis(bromomethyl)-1,3-propanediol,
2,2-bis(chloromethyl)-1,3-pronediol, 2,2-bis(fluoromethyl)-1,
3-Propanediol, N-phenyl-N'-(1
-hydroxy-2,2,2-trichloroethyl)
Thiourea, N-(1-hydroxy-2,2,2-
trichloroethyl)-thiobenzamide, N-(1
-hydroxy-2,2,2-tribromoethyl)
-thioacetamide, 3-(N-1-hydroxy-2,2,2-trichloroethyl)aminopyridine, 4-(2'-hydroxy-3',3',3'-trichloropropyl)pyridine, 2-( 1'-Hydroxy-
2',2',2'-trichloroethyl)furan, N-3
-pyridyl-N'-(1-hydroxy, 2,2,2
-trichloroethyl)urea, etc. Next, component (c) will be described. The aliphatic carboxylic acid anhydride may not only be an anhydride of the same kind of acid but also an anhydride of different kinds of acids. A specific example is given below. Caproic anhydride, enanthic anhydride, caprylic anhydride, pelargonic anhydride, capric anhydride, undecanoic anhydride, lauric anhydride, tridecanoic anhydride, myristic anhydride, pentadecanoic anhydride, palmitic anhydride, hexadecanoic anhydride, stearic anhydride Acid, arachidic anhydride, behenic anhydride, cerotic anhydride, octacosanoic anhydride, melisic anhydride, oleic anhydride, elaidic anhydride, linoleic anhydride, erucic anhydride, brassic anhydride, formic acid-acetic anhydride, propionic acid -acetic anhydride, isovaleric acid-acetic anhydride, caproic acid-acetic anhydride, enanthic acid-acetic anhydride, caprylic acid-acetic anhydride, pelargonic acid-acetic anhydride, capric acid-acetic anhydride, lauric acid - acetic anhydride, myristic acid-acetic anhydride, palmitic acid-acetic anhydride, stearic acid-acetic anhydride, caproic acid-lauric anhydride, caproic acid-myristic anhydride, caproic acid-palmitic anhydride, caproic acid-stearic anhydride, caproic acid-behenic anhydride, oleic acid-caprylic anhydride, oleic acid-lauric anhydride, oleic acid-myristic anhydride, oleic acid-palmitic anhydride,
Oleic acid-stearic anhydride, oleic behenic anhydride, stearic acid-caprylic anhydride, stearic acid-capric anhydride, stearic acid-lauric anhydride, stearic acid-myristic anhydride, stearic acid- Examples include palmitic anhydride. In addition, the following compound is used as component (c) in combination with the aliphatic carboxylic acid anhydride, and when component (c) is an acid anhydride alone, fine adjustment to slightly shift the discoloration temperature exhibited by the thermochromic material is possible. It will be done. Compounds used in combination with the aliphatic carboxylic anhydride include alcohols, esters, ketones, ethers, acid amides, aliphatic carboxylic acids having 6 or more carbon atoms, thiols, sulfides, disulfides, and Selected from nitrile compounds. Alcohols include monohydric alcohols, polyhydric alcohols, and derivatives thereof. Examples of these compounds are shown below. n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, n-lauryl alcohol, n-myristyl alcohol, n-cetyl alcohol, n-stearyl alcohol, n-icosyl alcohol, n-docosyl alcohol, n-
-mericyl alcohol, isocetyl alcohol,
Isostearyl alcohol, isodocosyl alcohol, oleyl alcohol, cyclohexanol, cyclopentanol, benzyl alcohol,
Cinnamyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol,
Examples include polyethylene glycol, propylene glycol, butylene glycol, hexylene glycol, cyclohexane-1,4-diol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, sorbitol, mannitol, and the like. Examples of compounds as esters are shown below. Amyl acetate, octyl acetate, butyl propionate, octyl propionate, phenyl propionate, ethyl caproate, amyl caproate, ethyl caprylate, amyl caprylate, ethyl caprate, amyl caprate, octyl caprate,
Methyl laurate, ethyl laurate, butyl laurate, hexyl laurate, octyl laurate, dodecyl laurate, myristyl laurate, cetyl laurate, stearyl laurate,
Methyl myristate, ethyl myristate, butyl myristate, hexyl myristate, octyl myristate, lauryl myristate, myristyl myristate, cetyl myristate, stearyl myristate, methyl palmitate, ethyl palmitate, butyl palmitate, palmitic acid Hexyl, octyl palmitate, lauryl palmitate, myristyl palmitate, cetyl palmitate, stearyl palmitate, methyl stearate, ethyl stearate, butyl stearate, hexyl stearate, octyl stearate, lauryl stearate, myristyl stearate , cetyl stearate, stearyl stearate, methyl behenate, ethyl behenate, propyl behenate, butyl behenate, ethyl benzoate, butyl benzoate, amyl benzoate, phenyl benzoate, ethyl acetoacetate, methyl oleate, olein butyl acid, butyl acrylate, diethyl oxalate, dibutyl oxalate, diethyl malonate, dibutyl malonate, dibutyl tartrate, dibutyl sebatate, dimethyl sebatate, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, dibutyl fumarate, Examples include diethyl maleate, dibutyl maleate, triethyl citrate, 12-hydroxystearic acid triglyceride, castor oil, dioxystearic acid methyl ester, and 12-hydroxystearic acid methyl ester. The following compounds are exemplified as ketones. Diethyl ketone, ethyl butyl ketone, methylhexyl ketone, mesityl oxide, cyclohexanone, methylcyclohexanone, acetophenone, propiophenone, benzophenone, 2,4
- Pentanedione, acetonyl acetone, diacetone alcohol, ketone wax, etc. The following compounds are exemplified as ethers. Butyl ether, hexyl ether, diisopropyl benzyl ether, diphenyl ether,
Examples include dioxane, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol diphenyl ether, and ethylene glycol monophenyl ether. Examples of acid amide compounds are shown below. 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 alinide, capric acid alinide,
Lauric acid anilide, myristic acid anilide, palmitic acid anilide, stearic acid anilide, behenic acid anilide, oleic acid anilide, erucic acid anilide, caproic acid anilide, caprylic acid anilide, capric acid anilide, lauric acid anilide 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-methylamide
-Ethylamide, myristic acid N-ethylamide, palmitic acid N-ethylamide, stearic acid N-ethylamide, oleic acid N-ethylamide, lauric acid N-butylamide, myristic acid N-butylamide, palmitic acid N-butylamide, stearic acid N-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 acid N-
dodecylamide, palmitic acid N-dodecylamide, stearic acid N-dodecylamide, oleic acid N-dodecylamide, distearic acid amide,
Dipalmitic acid amide, Dimyristic acid amide,
dilauric acid amide, dioleic acid amide, tristearic acid amide, tripalmitic acid amide,
trimyristic acid amide, trilauric 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-titylamide, azelaic acid N-methylamide, succinic acid N-ethylamide, adipic acid N-methylamide
-ethylamide, glutaric acid N-ethylamide,
Malonic acid N-ethylamide, azelaic acid N-ethylamide, succinic acid N-butylamide, adipic acid N-butylamide, glutaric acid N-butylamide, malonic acid N-butylamide, adipic acid N-butylamide
-octylamide, adipic acid N-dodecylamide, etc. Aliphatic carboxylic acids having 6 or more carbon atoms include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melisic acid. , isomyristic acid, isopalmitic acid, isostearic acid,
Oleic acid, elaidic acid, linoleic acid, linolenic acid, eleostearic acid, arachidonic acid, 2-
Oxylauric acid, 2-oxymyristic acid, 2
-Oxypalmitic acid, 2-oxystearic acid, 3-oxystearic acid, 12-hydroxystearic acid, ricinoleic acid, 2-bromurauric acid, 2-bromyristic acid, 2-brompalmitic acid, 2-bromostearic acid, 18-bromstearic acid, 2-chlorostearic acid, 18-chlorostearic acid, dioxypalmitic acid, dioxystearic acid, 3-ethyl-3-lauryl-3
Oxypropionic acid, 2-methyl-3-oxystearic acid, 2-ketostearic acid, 2-ketopalmitic acid, azelaic acid monoethyl ester, azelaic acid monobutyl ester, azelaic acid monooctyl ester, sebacic acid mominoethyl ester , sebacic acid monobutyl ester,
Examples include sebacic acid monooctyl ester, sebacic acid monolauryl ester, 1,12-dodecamethylene dicarboxylic acid, 1,14-tetradecamethylene dicarboxylic acid, 1,16-hexadecamethylene dicarboxylic acid, and dimer acid. Examples of thiol compounds are shown below. n-decyl mercaptan, n-dodecyl mercaptan, n-myristyl mercaptan, n-cetyl mercaptan, n-stearyl mercaptan,
Examples include iso-dodecyl mercaptan, iso-myristyl mercaptan, iso-cetyl mercaptan, and dodecylbenzyl mercaptan. Examples of sulfide compounds are shown below. Di-n-octyl sulfide, di-n-nonyl sulfide, di-n-decyl sulfide, di-n
-Dodecyl sulfide, di-n-myristyl sulfide, di-n-cetyl sulfide, di-n-stearyl sulfide, di-t-dodecyl sulfide, octyldodecyl sulfide, diphenyl sulfide , dibenzyl sulfide, ditolyl sulfide, diethyl phenyl sulfide, 4,4-
Examples include dichlorodiphenyl sulfide, dilaurylthiodipropionate, distearylthiodipropionate, tetra(laurylthiopropionic acid) pentaerythritol ester, and tetra(stearylthiopropionate)pentaerythritol. Examples of disulfide compounds are shown below. Di-n-decyl disulfide, di-n-dodecyl disulfide, di-n-myristyl disulfide, di-n-cetyl disulfide, di-n-stearyl disulfide, diphenyl disulfide ,
dibenzyl disulfide, ditolyl disulfide,
Examples include dinaphthyl disulfide and 4,4-dichlorodiphenyl disulfide. The above three components (a), (b) and (c) are mixed in a weight ratio of 1:
The thermochromic material of the present invention can be obtained by mixing and melting in a ratio of 0.1 to 10:1 to 100 to obtain a homogeneous composition. The thermochromic material of the present invention becomes liquid or paste at a temperature slightly higher than its color change temperature, and contains a strong acidic substance or component (a) that irreversibly colors the electron-donating color-forming organic compound of component (a). Its properties may be impaired when it comes into contact with other substances, such as substances that interfere with the reactions of (b) and (b). The above-mentioned problem can be solved by forming the thermochromic material into microcapsules with particle diameters of several μm to about 30 μm using the well-known microencapsulation method, and also allows two or more different types of discoloration to be produced in the same system. It is also possible to coexist with a thermochromic material that indicates temperature, expanding its uses. A specific example will be explained below. The thermochromic material of each example was obtained by mixing and melting components (a), (b), and (c) at about 100°C to form a homogeneous composition. Examples 11 and 12 are examples of thermochromic materials encapsulated in microcapsules. Table 1 shows the composition, color change temperature, and color change of the thermochromic materials of Examples 1 to 10. The numbers in parentheses in the table are composition ratios expressed in parts by weight, and the discoloration temperature indicates the center point of the temperature range where discoloration occurs in °C.The color change is shown on the left side of the arrow. The color at a temperature higher than the discoloration temperature is shown on the right side. Details of component (a) in the table are as follows. CVL: Crystal Violet Lactone Leuco Dye A: Spiro [isobenzofuran-1
(3H), 9′-[9H]xanthene]-3-one,
6′-ethylamino-3′-methyl-2′-(phenylamino)-leuco dye B: spiro[12-H-benzo[α]xanthene-12.1′(3′H)-isobenzofuran]
-3'-one, 9-(diethylamino)-leuco dye C: spiro[isobenzofuran-1
(3H), 9′-[9H]xanthene]-3-one,
6′-(diethylamino)-2′-[cyclohexyl(phenylmethyl)amino]- leuco dye D: spiro[isobenzofuran-1
(3H), 9′-[9H]xanthene]-3-one,
2'-chloro-6'-(diethylamino)-3'-methyl-

【table】

Claims (1)

[Scope of Claims] 1. Essential components include (a) an electron-donating color-forming organic compound, (b) a compound having a phenolic hydroxyl group and its metal salt, an aromatic carboxylic acid and its metal salt, and a carbon number of 2 to 5. aliphatic carboxylic acid and its metal salt, acidic phosphoric acid ester and its metal salt, 1,
2,3-triazole and its derivatives, carbon number 2
A thermochromic material comprising a composition containing one or more compounds selected from halohydrins and their derivatives as described in (3) to (5) an aliphatic carboxylic acid anhydride. 2. The thermochromic material according to claim 1, which is encapsulated in microcapsules.