JPH115973A - Reversibly thermochromic composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition that shows a reversibly thermochromic behavior, in which a temperature increase upon heating in a decolored state is utilized as a trigger, and during the course of temperature fall after heating, it begins coloration, exhibits the maximum density of a developed color and is restored into a decolored state by using an electron-donating color-forming compound, an electron-accepting compound comprising an alkoxyphenol compound and a reaction medium as the essential components. SOLUTION: The electron-donating color-forming organic compound (A) used is conventionally known diphenylmethanphthalides, etc. The electron- accepting compound (B) used is represented by the formula (wherein R is an alkyl, desirably a 3-18C alkyl) and is exemplified by p-n-propyloxyphenol. The reaction medium (C) used to reversibly effect an electron transfer reaction in a specified temperature range is exemplified by an alcohol (e.g. decyl alcohol) or an ester. The mixing ratio among components A, B and C is 1/(0.1-50)/(5-100). The composition is used in the form of microcapsules.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a reversible thermochromic composition. Specifically, the present invention relates to a reversible thermochromic composition which reversibly generates a color-developed state and a decolored state by a temperature change.
More specifically, a reversible color change function that triggers the temperature rise due to heating from the decolored state, starts color development in the process of cooling after heating, develops the color development state with the maximum color density, and returns to the decolored state A reversible thermochromic composition comprising:

[0002]

2. Description of the Related Art Heretofore, several proposals have been disclosed for a reversible thermochromic composition which causes a reversible color change in a specific temperature range by an electron transfer reaction (Japanese Patent Publication No. 51-35).
No. 414, JP-B-51-44706, JP-B-51-44708, JP-B-52-7774, JP-B-1-29398, JP-B4-17154, and JP-A-7-186546. etc). The proposal for the conventional reversible thermochromic composition described above starts decoloring in the process of raising the temperature from the color-developing state, presents a complete decoloring state at a specific temperature or higher, starts color development in the subsequent temperature-lowering process, and starts the color-developing state. Having a function of exhibiting a reversible thermochromic property that returns to the state shown in FIG.
Reference) and are applied to the field of temperature indicator materials and toys.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have pursued a reversible thermochromic composition and have further studied.
The present inventors have found a reversible thermochromic composition exhibiting a unique discoloration behavior, which is different from a composition exhibiting a behavior of decoloring by the conventional heating and continuing to exhibit a colored state by cooling. That is, (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound,
(C) In the composition composed of the two reaction media, by applying a specific compound as the component (b), a temperature rise by heating is used as a trigger, and a color development state with a maximum color density is exhibited in a temperature decreasing process after heating. After that, a phenomenon of returning to the decolored state was found, and the present invention was completed. Since the composition of the present invention can show a color-developed state with the temperature rise caused by heating as a trigger, a temperature-indicating field, a surprising property and a taste of discoloration that cannot be achieved by the conventional thermochromic composition are required. An object of the present invention is to provide a novel reversible thermochromic composition that can be applied to various fields such as a toy field, a decoration field, and a design field.

[0004]

According to the present invention, there is provided a reversible thermochromic composition which emits and decolors by an electron transfer reaction, wherein the temperature is raised by heating from a decolored state as a trigger, and the temperature is lowered during heating. A reversible thermochromic composition having a reversible color-changing function that starts color development, develops a color-developing state with the maximum color-developing density, and then returns to a decolored state is a requirement. Further, (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound selected from alkoxyphenol compounds represented by the following general formula (1), and (c) the above-mentioned (a) and (b) A compound that is a reaction medium that causes the electron transfer reaction to occur reversibly in a specific temperature range is an essential component. Heating from the decolored state is triggered, and color development is started in the process of cooling after heating to produce the maximum color density. A reversible thermochromic composition having a reversible color change function that returns to a decolored state after developing a state is a requirement.

(R represents an alkyl group.) Further, the alkyl group of the alkoxyphenol compound represented by the general formula (1) is a straight-chain or side-chain alkyl group having 3 to 18 carbon atoms; In the component (C), chain hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons,
And one or more compounds selected from halogenated hydrocarbons; the reversible thermochromic composition encapsulated in microcapsules; and the heating temperature is (c)
And the like.

The above-mentioned (a) electron-donating color-forming organic compounds include diphenylmethanephthalides known in the art,
Phenylindolyl phthalides, indolyl phthalides, diphenylmethane azaphthalides, phenyl indolyl azaphthalides, fluorans, styrinoquinolines, diaza rhodamine lactones, and the like.Examples of these compounds are given below. I do. 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3
-(4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, 3,3
-Bis (1-n-butyl-2-methylindole-3-
Yl) phthalide, 3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- [2
-Ethoxy-4- (N-ethylanilino) phenyl]-
3- (1-ethyl-2-methylindol-3-yl)
-4-azaphthalide, 3,6-dimethoxyfluoran,
3,6-di-n-butoxyfluoran, 2-methyl-6
-(N-ethyl-N-p-tolylamino) fluoran,
3-chloro-6-cyclohexylaminofluoran, 2
-Methyl-6-cyclohexylaminofluoran, 2-
(2-chloroanilino) -6-di-n-butylaminofluoran, 2- (3-trifluoromethylanilino)-
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-methyl-6-di-n-butylaminofluoran, 2-xyridino-3-
Methyl-6-diethylaminofluoran, 1,2-benz-6-diethylaminofluoran, 1,2-benz-
6- (N-ethyl-N-isobutylamino) fluoran, 1,2-benz-6- (N-ethyl-N-isoamylamino) fluoran, 2- (3-methoxy-4-dodecoxystyryl) quinoline, Spiro [5H- (1) benzopyrano (2,3-d) pyrimidine-5,1 ′ (3 ′
H) Isobenzofuran] -3'-one, 2- (diethylamino) -8- (diethylamino) -4-methyl-, spiro [5H- (1) benzopyrano (2,3-d) pyrimidine-5,1 '( 3'H) isobenzofuran] -3'-
On, 2- (di-n-butylamino) -8- (di-n-
Butylamino) -4-methyl-, spiro [5H- (1)
Benzopyrano (2,3-d) pyrimidine-5,1 '
(3'H) isobenzofuran] -3'-one, 2- (di-n-butylamino) -8- (diethylamino) -4-
Methyl-, spiro [5H- (1) benzopyrano (2,3
-D) pyrimidine-5,1 '(3'H) isobenzofuran] -3'-one, 2- (di-n-butylamino) -8
-(N-ethyl-Ni-amylamino) -4-methyl-, spiro [5H- (1) benzopyrano (2,3-d)
Pyrimidine-5,1 '(3'H) isobenzofuran]-
3′-one, 2- (di-n-butylamino) -8- (di-n-butylamino) -4-phenyl and the like. Further, pyridine-based, quinazoline-based, bisquinazoline-based compounds, and the like, which are effective for expressing fluorescent yellow to red colors can be given.

The (b) electron-accepting compound is selected from the alkoxyphenol compounds represented by the general formula (1), wherein the alkyl group of the compound has 3 to 18 carbon atoms.
It is preferred that That is, in a system having an alkyl group having less than 3 or more than 18 carbon atoms, the color development density is low, so that practicality is not satisfied. Further, the alkyl group may be a straight-chain or side-chain alkyl group, more preferably a straight-chain alkyl group, and still more preferably 8 carbon atoms.
Compounds having from 12 to 12 straight-chain alkyl groups are preferred because they effectively exhibit a color-forming function. The compounds are exemplified below. p-n-propyloxyphenol, p-n-butyloxyphenol, p-n-pentyloxyphenol, p-n-hexyloxyphenol, p-n-heptyloxyphenol, p-n-octyloxyphenol, p- n-nonyloxyphenol, pn-decyloxyphenol, pn-undecyloxyphenol, pn-dodecyloxyphenol, pn-tridecyloxyphenol, pn-tetradecyloxyphenol, p -N-pentyldecyloxyphenol, pn-heptyldecyloxyphenol, pn
-Hexyldecyloxyphenol, pn-octyldecyloxyphenol, p-isopropyloxyphenol, p-1-methylpropyloxyphenol, p
-3-methylbutyloxyphenol, p-2-methylpentyloxyphenol, p-1-ethylpentyloxyphenol, p-1-ethylhexyloxyphenol, p-3,5,5-trimethylhexyloxyphenol, p-3 , 7-dimethyloctyloxyphenol, p-1-ethylpropyloxyphenol, p-2
-Methylhexyloxyphenol, p-1-methylheptyloxyphenol, p-1-methyloctyloxyphenol and the like.

(C) As a compound which is a reaction medium for causing the electron transfer reaction according to the above (a) and (b) to occur reversibly in a specific temperature range, alcohols, esters, ketones, ethers, acid amides Conventionally, general-purpose reaction media are all effective, and one or more of these compounds can be applied. When applied to microencapsulation and secondary processing using each of the above compounds, those having a low molecular weight evaporate out of the capsule system when subjected to high heat treatment. The above compounds are effective. Alcohols have 10 carbon atoms
The above aliphatic monohydric saturated alcohols are effective, and specifically, decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol , Eicosyl alcohol, docosyl alcohol and the like.

[0008] As the esters, esters having 10 or more carbon atoms are effective. The esters of a monovalent carboxylic acid having an aliphatic and alicyclic or aromatic ring and a monohydric alcohol having an aliphatic and alicyclic or aromatic ring are useful. Esters and aliphatics obtained from any combination of esters, aliphatic and alicyclic or aromatic polyhydric carboxylic acids and aliphatic and alicyclic or aromatic monohydric alcohols obtained from any combination And esters obtained from any combination of a monovalent carboxylic acid having an alicyclic or aromatic ring and a polyhydric alcohol having an aliphatic and an alicyclic or aromatic ring, and specifically, ethyl caprylate and caprylic acid. Octyl, 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 stearate
-Trimethylhexyl, n-undecyl stearate,
Pentadecyl stearate, stearyl stearate,
Cyclohexylmethyl stearate, isopropyl behenate, hexyl behenate, lauryl behenate, behenyl behenate, cetyl benzoate, stearyl p-tert-butyl benzoate, dimyristyl phthalate, distearyl phthalate, dimyristyl oxalate, dicetyl oxalate ,
Dicetyl malonate, dilauryl succinate, dilauryl glutarate, diundecyl adipate, dilauryl azelate, di- (n-nonyl) sebacate, dineopentyl 1,18-octadecylmethylenedicarboxylate, ethylene glycol dimyristate, propylene glycol dilaurate, Propylene glycol distearate,
Hexylene glycol dipalmitate, 1,5-pentanediol distearate, 1,2,6-hexanetriol trimiristate, 1,4-cyclohexanedioldidecyl, 1,4-cyclohexanedimethanol dimyristate, xylene Examples thereof include glycol dicaprinate and xylene glycol distearate.

Esters of saturated fatty acids and branched aliphatic alcohols, unsaturated fatty acids or branched or substituted saturated fatty acids and esters of aliphatic alcohols having 16 or more carbon atoms, cetyl butyrate, Ester compounds selected from stearyl butyrate and behenyl butyrate are also effective. Specifically, 2-ethylhexyl butyrate, 2-ethylhexyl behenate, 2-ethylhexyl myristate, 2-ethylhexyl caprate, lauric acid 3,
5,5-trimethylhexyl, palmitic acid 3,5,5
-Trimethylhexyl, 3,5,5-trimethylhexyl stearate, 2-methylbutyl caproate, 2-methylbutyl caprylate, 2-methylbutyl caprate,
1-ethylpropyl palmitate, 1-ethylpropyl stearate, 1-ethylpropyl behenate, 1-ethylhexyl laurate, 1-ethylhexyl myristate, 1-ethylhexyl palmitate, 2-caproic acid
Methylpentyl, 2-methylpentyl caprylate, 2-methylpentyl caprate, 2-methylpentyl laurate, 2-methylbutyl stearate, 2 stearic acid
-Methylbutyl, 3-methylbutyl stearate, 1-methylheptyl stearate, 2-methylbutyl behenate, 3-methylbutyl behenate, 1-methylheptyl stearate, 1-methylheptyl behenate, 1-ethylpentyl caproate, palmitin 1-ethylpentyl acid, 1-methylpropyl stearate, 1 stearic acid
-Methyloctyl, 1-methylhexyl stearate,
1,1-dimethylpropyl laurate, 1-capric acid
Methylpentyl, 2-methylhexyl palmitate, 2-methylhexyl stearate, 2-methylhexyl behenate, 3,7-dimethyloctyl laurate, 3,7-dimethyloctyl myristate, 3,7 palmitate
-Dimethyloctyl, 3,7-dimethyloctyl stearate, 3,7-dimethyloctyl behenate, 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, 2
-Isostearyl ketomyristate, 2-ethylhexyl 2-fluoromyristate, cetyl butyrate, stearyl butyrate, behenyl butyrate and the like.

Further, carboxylic acid ester compounds disclosed in Japanese Patent Publication No. 4-17154, for example, a carboxylic acid ester having a substituted aromatic ring in the molecule, a carboxylic acid having an unsubstituted aromatic ring in the molecule, and a carboxylic acid having 10 or more carbon atoms Esters of aliphatic alcohols, 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, fatty acids having 8 or more carbon atoms and branched aliphatic alcohols or esters, dicarboxylic acids Esters of acids and aromatic or branched aliphatic alcohols, dibenzyl cinnamate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, dicetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearin , Dimyristin, Stearic and the like.

A fatty acid ester compound obtained from an odd aliphatic monohydric alcohol having 9 or more carbon atoms and an aliphatic carboxylic acid having an even carbon number, n-pentyl alcohol or n-heptyl alcohol and an even aliphatic compound having 10 to 16 carbon atoms. Fatty acid ester compounds having a total of 17 to 23 carbon atoms obtained from aliphatic carboxylic acids are also effective. Specifically, n-pentadecyl acetate, n-tridecyl butyrate, n-pentadecyl butyrate, n-undecyl caproate, n-tridecyl caproate, n-pentadecyl caproate, n-nonyl caprylate, n-undecyl caprylate, N-tridecyl caprylate, n-pentadecyl caprylate, n-caprate
Heptyl, n-nonyl caprate, n-undecyl caprate, n-tridecyl caprate, n-pentadecyl caprate, n-pentyl laurate, n-laurate
Heptyl, n-nonyl laurate, n-undecyl laurate, n-tridecyl laurate, n-pentadecyl laurate, n-pentyl myristate, n-heptyl myristate, 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-stearate
-Nonyl, n-undecyl stearate, n-tridecyl stearate, n-pentadecyl stearate, n-nonyl eicosanoate, n-undecy eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate, n-nonyl behenate , N-undecyl behenate, n-tridecyl behenate and n-pentadecyl behenate.

As the ketones, aliphatic ketones having a total carbon number of 10 or more are effective, and 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, 5-undecanone, Undecanone, 2-dodecanone, 3-dodecanone, 4-dodecanone, 5-dodecanone, 2-tridecanone, 3-tridecanone, 2-tetradecanone, 2-pentadecanone, 8-pentadecanone, 2-hexadecanone, 3-hexadecanone, 9-heptacanone, Examples thereof include 2-pentadecanone, 2-octadecanone, 2-nonadecanone, 10-nonadacanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, lauron, and stearone. Further, arylalkyl 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-octyl acetophenone, n-nonanophenone, 4-n-heptyl acetophenone, n-
Octanophenone, 4-n-hexyl acetophenone,
4-n-cyclohexyl acetophenone, 4-tert
-Butylpropiophenone, n-heptaphenone, 4-
n-Pentyl acetophenone, cyclohexyl phenyl ketone, benzyl-n-butyl ketone, 4-n-butyl acetophenone, n-hexanophenone, 4-isobutyl acetophenone, 1-acetonaphthone, 2-acetonaphthone, cyclopentyl phenyl ketone, and the like. .

As ethers, aliphatic ethers having a total carbon number of 10 or more are effective, such as dipentyl ether,
Dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, didodecyl ether, ditridecyl ether, ditetradecyl ether, dipentadecyl ether, dihexadecyl ether, dioctadecyl ether, decane Examples thereof include diol dimethyl ether, undecane diol dimethyl ether, dodecane diol dimethyl ether, tridecane diol dimethyl ether, decane diol diethyl ether, and undecane diol diethyl ether.

As the acid amide, the following compounds can be exemplified. Acetamide, propionamide, butyric amide, caproic amide, caprylic amide, capric amide, lauric amide, myristic amide, palmitic amide, stearic amide, behenic amide, oleic amide, erucamide, benzamide , Caproic anilide, caprylic anilide, capric anilide, lauric anilide, myristic anilide, palmitic anilide, stearic anilide,
Behenic acid anilide, oleic acid anilide, erucic acid anilide, caproic acid N-methylamide, caprylic acid N-
Methylamide, capric acid N-methylamide, lauric acid N-methylamide, myristic acid N-methylamide,
Palmitic acid N-methylamide, stearic acid N-methylamide, behenic acid N-methylamide, oleic acid N
-Methylamide, erucic acid N-methylamide, lauric acid N-ethylamide, myristic acid N-ethylamide,
Palmitic acid N-ethylamide, stearic acid N-ethylamide, oleic acid N-ethylamide, lauric acid N
-Butylamide, N-butylamide myristic acid, N-butylamide palmitate, N-butylamide stearate, N-butylamide oleate, N-octylamide laurate, N-octylamide myristic acid, N-octylamide palmitate, 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 amide, dimyristic amide, dipalmitic amide, distearic amide, dioleic amide, trilauric amide, trimylic amide,
Tripalmitic acid amide, tristearic acid amide, trioleic acid amide, succinic amide, adipic amide, glutaric amide, malonamide, azelaic amide, maleic amide, succinic N-methylamide, adipic N-methylamide , Glutaric acid N-methylamide, malonic acid N-methylamide, azelaic acid N
-Methylamide, succinic N-ethylamide, adipic N-ethylamide, glutaric N-ethylamide, malonic N-ethylamide, azelaic N-ethylamide, succinic N-butylamide, adipic N-butylamide, glutaric N-butylamide , Malonic acid N-butylamide, adipic acid N-octylamide, adipic acid N-dodecylamide.

Further, a compound selected from the group consisting of chain hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons can be used in combination with the above-mentioned component (c). By adding one or more of the above compounds, a reversible thermochromic composition having higher coloring density and excellent practicability can be obtained.

Among the above-mentioned chain hydrocarbons, saturated chain hydrocarbons include pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, heneicosane, docosane, trichosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, Triacontan and the like can be exemplified. Examples of unsaturated chain hydrocarbons include 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene,
Nonadecene, 1-eicosene, 1-heneicosene, 1
-Dococene, 1-tricosene, 1-tetracosene, 1-
Pentacocene, 1-hexacocene, 1-heptacocene,
Examples thereof include 1-octacocene, 1-nonacocene, and 1-triaconten.

Examples of the alicyclic hydrocarbon include cyclooctane, cyclododecane, n-pentadecylcyclohexane, n-octadecylcyclohexane, n-nonadecylcyclohexane, decahydronaphthalene and the like.

The aromatic hydrocarbons include dodecylbenzene, biphenyl, ethylbiphenyl, 4-benzylbenzene, phenyltolylmethane, diphenylethane,
1,3-diphenylbenzene, dibenzyltoluene, methylnaphthalene, 2,7-diisopropylnaphthalene,
Examples thereof include methyltetralin and naphthylphenylmethane.

Examples of the halogenated hydrocarbon include 1-bromodecane, 1-bromoundecane, 1-bromododecane, 1-bromotridecane, 1-bromotetradecane,
1-bromopentadecane, 1-bromohexadecane, 1
-Bromoheptadecane, 1-bromooctadecane, 1-
Bromoeicosane, 1-bromodocosane, 1-chlorodecane, 1-chlorotetradecane, 1-chlorohexadecane, 1-chloroheptadecane, 1-chlorooctadecane, 1-chloroeicosane, 1-chlorodocosan, 1-
Examples thereof include iodotetradecane, 1-iodohexadecane, 1-iodoheptadecane, and 1-iodooctadecane.

Further, waxes or middle molecular weight polymers may be added to the component (c). When the above hydrocarbons are contained in the waxes and the medium molecular weight polymers, the same effect is exerted. Examples of the waxes and medium molecular weight polymers include paraffin wax having a melting point of 50 to 120 ° C, microcrystalline wax, petrolactam, oxidized paraffin wax, and petrolactam oxide. Shellac, sugarcane wax, carnauba wax, candelilla wax, caster wax, hardened tallow oil, hardened fish oil, hardened rapeseed oil, montan wax, palm wax, amberjack,
Hazerow, wool fat, etc. Polyethylene wax, montanic acid wax, ethylene-vinyl acetate copolymer wax, ethylene acrylic copolymer wax, vinyl ether wax, etc. Examples include palm oil, babassu oil, liquid paraffin, polybutene, polybutadiene, polystyrene oligomer, and the like.

The composition of the present invention comprises the above (a), (b),
(C) A compatibilizer containing a component as an essential component, and the ratio of each component depends on the concentration, discoloration temperature, discoloration form, and type of each component. ,
The component (b) is in the range of 0.1 to 50, preferably 0.5 to 20, and the component (c) is 5 to 100, preferably 20 to 50, relative to the component 1. Parts by weight).

The color change characteristics of the reversible thermochromic composition comprising a mixture of the components (a), (b) and (c) will be described with reference to a graph showing a color density-temperature curve in FIG. In FIG. 1, the vertical axis represents color density, and the horizontal axis represents temperature. The change in the color density due to the temperature change proceeds along the arrow. Here, the temperature T ₁ indicates the complete melting temperature of the reversible thermochromic composition,
₂ indicates the color development temperature, T ₃ indicates the complete color development temperature,
T ₄ shows the complete decoloring temperature. Therefore, the composition which has been heated to a temperature exceeding T ₁ will have a temperature T ₂ during the cooling process.
Color density begins to color to reach darker, becomes completely colored state at a temperature T _3, exhibits a maximum color density, thinner color density when further cooled, completely decolorized when it reaches the temperature T _4. Composition was cooled to below the temperature T _4, by heating to a temperature exceeding T ₁ again reversibly to reproduce the discolouration behavior.

It is not clear why the composition of the present invention gives the color density-temperature curve shown in the above-mentioned graph.
The high crystallinity of the component (b) is related to the behavior of the component (c) due to melting, which affects the electron transfer reaction of the component (a) and the component (b), and exhibits the discoloration behavior of emission and decoloration. It is inferred. To explain this point, in the compatible solution of the components (a), (b), and (c), the component is brought into a solution state by heating at a temperature equal to or higher than the melting point of the component (c), and the (b) alkoxy is in a crystallized state. Since the phenol compound is redissolved and the component (a) is present in an independent state, it is in a decolored state. During the cooling process from this state, the component (c) gradually starts to solidify, The component and the component (ii) are ionized and combined to form a color. It is presumed that when the temperature is further decreased, the crystallization of the component (b) starts, the bond between the components (a) and (b) is broken, and the color starts to be erased, and finally, a colorless and decolored state is exhibited.

Thus, the discoloration behavior of the reversible thermochromic composition of the present invention (FIG. 1) is based on the discoloration behavior of the conventional heating-decoloring type reversible thermochromic composition (the color density-temperature curve of FIG. 9). The behavior is completely different from the example shown in the graph shown in FIG.

Although the reversible thermochromic composition of the present invention is effective when used as it is, it is preferable to use it in a microcapsule. It consists of acidic substances, basic substances,
Even if it comes in contact with chemically active substances such as peroxides or other solvent components, it does not lower its function, of course, it can maintain heat stability, and it is reversible under various use conditions. The thermochromic composition is kept at the same composition,
This is because the same operation and effect can be achieved. The microcapsule pigment containing the reversible thermochromic composition has a particle size of 0.1 to 100 μm, preferably 3 to 30 μm.
The range of m satisfies the practicality. The microencapsulation is carried out by a conventionally known interfacial polymerization method, in situ polymerization method, in-liquid curing coating method, phase separation method from aqueous solution, phase separation method from organic solvent, melting dispersion cooling method, air suspension. There are a coating method, a spray drying method, and the like, which are appropriately selected according to the application. Further, a secondary resin film may be provided on the surface of the microcapsules according to the purpose to impart durability, or the surface characteristics may be modified for practical use.

Each of the components (a), (b) and (c) may be a mixture of two or more compounds, and a light stabilizer may be added as long as the function is not hindered. Can be. Examples of the light stabilizer include an ultraviolet absorber, a visible light absorber, an infrared absorber, an antioxidant, a carotene, a dye, an amine, which prevent light deterioration caused by an excited state due to a photoreaction of the component (a). Compounds that suppress the oxidation reaction, such as singlet oxygen quenchers such as phenols, nickel complexes, and sulfides, superoxide anion quenchers such as complexes of oxide dismutase and cobalt, and nickel, and ozone quenchers. , 0.3 to 24% by weight,
Preferably, it is blended in the system at a ratio of 0.8 to 16% by weight. Among them, the ultraviolet absorber, an antioxidant and / or
Alternatively, a system using a singlet oxygen quencher is particularly effective for improving light resistance. Further, an anti-aging agent, an antistatic agent, a polarity-imparting agent, a thixotropic agent, an antifoaming agent and the like can be added as required to improve the function. Further, the above-described conventional reversible thermochromic composition may be blended in an appropriate ratio, or a general dye / pigment (non-thermochromic) may be blended.

The reversible thermochromic composition or the microcapsule pigment containing the same is dispersed in a medium containing a binder which is a film forming material and applied as a reversible thermochromic material such as ink or paint. More known methods, for example, screen printing, offset printing, gravure printing, coater, printing means such as tampo printing, transfer, brush coating, spray coating, electrostatic coating, electrodeposition coating, flow coating, roller coating, dip coating, Paper, synthetic paper,
Cloth, flocking or brushed cloth, non-woven fabric, synthetic leather, leather,
It can be formed on a support such as plastic, glass, ceramics, wood, and stone, or can be dispersed in the support. Furthermore, in the form of microcapsule pigments,
It can be applied as a material that is kneaded and integrated into a molten thermoplastic plastic.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The reversible thermochromic composition of the present invention comprises:
For example, it is used as a colorant for paints, printing inks, writing inks, paints, and the like, or as a colorant contained in a molded product obtained by molding with a thermoplastic resin or a thermosetting resin.

[0029]

The following table shows the compositions of the components (a), (b) and (c) of the reversible thermochromic composition of the present invention (Examples 1 to 29).
The color change, the complete melting temperature (T ₁ ), the color development start temperature (T ₂ ), the complete color development temperature (T ₃ ), and the complete decolorization temperature (T ₄ ) are shown, but the present invention is not limited to the examples. Absent. The numbers in parentheses in the table indicate parts by weight, and the numbers indicating the following amounts are all parts by weight.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

Here, the discoloration characteristics of the reversible thermochromic composition of the above-mentioned example were determined by printing on a support an ink prepared by dispersing a microcapsule pigment prepared in the following manner in a vehicle, and measuring with a colorimeter. Obtained. Preparation of microcapsule pigment (a), (b), and (c) The components were heated and dissolved at 120 ° C to form a compatible solution, and then encapsulated in an epoxy resin film by an interfacial polymerization method of an epoxy resin / amine curing agent. Thus, a reversible thermochromic microcapsule pigment in the form of microcapsules was obtained. Measurement Sample and Measurement Method Using a reversible thermochromic ink obtained by dispersing 40 parts of the reversible thermochromic microcapsule pigment in an ethylene-vinyl acetate emulsion, a printed matter printed on high-quality paper by screen printing as a measurement sample, Color difference meter [TC-3600
Type color difference meter, manufactured by Tokyo Denshoku Co., Ltd.)
Heating and cooling were performed at a temperature range of 50 ° C. at a rate of 10 ° C./min, and the lightness values displayed on the color difference meter at each temperature were plotted on a graph. Further, for Examples 19 to 29,
The lightness value at the complete coloring temperature (T ₃ ) and the complete erasing temperature (T ₃ )
₄ ) The brightness values at the time are shown in the table below.

[0034]

[Table 4]

Examples 2, 4, 8, 10, 19, and 2
The change in temperature and the change in color density of a printed matter printed using the thermochromic microcapsule pigments containing the reversible thermochromic compositions 0 and 21 will be described with reference to a graph.

Example 2 (See FIG. 2) As the colorless printed matter cooled to 20 ° C. or lower is heated, the color slightly develops at around 32 ° C. to give a light blue color. When the composition is further heated to a temperature equal to or higher than the complete melting temperature (T ₁ : 36 ° C.) at which the component (c) of the composition melts, the light blue color disappears and returns to completely colorless, and the temperature is increased to 36 ° C. or higher. When the printed matter is allowed to cool, the color starts to be developed at a temperature lower than the color development start temperature (T ₂ : 30 ° C.), and the blue color gradually becomes darker. At the full color development temperature (T ₃ : 24 ° C.), the blue color becomes deepest. , Exhibiting the maximum color density. As the color is further cooled, the blue color gradually fades, and when the temperature becomes lower than the complete decoloring temperature (T ₄ : 20 ° C.), the color returns to a colorless state. When heated to 36 ° C. or more again, the same color change is repeatedly and reversibly generated. In addition, when the mixture is heated again from the complete melting temperature (T ₁ : 36 ° C.) or more while cooling from 30 ° C. to 20 ° C., the color changes from blue to colorless, and the same color change is exhibited even when cooled from this state. .

Example 4 (See FIG. 3) A printed matter which is colorless at room temperature of 25 ° C. is heated to a temperature equal to or higher than the complete melting temperature (T ₁ : 47 ° C.) at which the component (c) melts, and then allowed to cool. Then, the color starts to be developed at a temperature lower than the color development start temperature (T ₂ : 38 ° C.), and the blue color gradually becomes darker.
At the full color development temperature (T ₃ : 33 ° C.), the blue color becomes darkest,
Presents the maximum color density. As the color is further cooled, the blue color gradually becomes lighter, and when the temperature becomes lower than the complete decoloring temperature (T ₄ : 30 ° C.), the color returns to a colorless state. When heated again to 47 ° C or higher,
The same color change is reversibly generated repeatedly. Incidentally, 38
When the mixture is heated again from the complete melting temperature (T ₁ : 47 ° C.) or more while cooling from 30 ° C. to 30 ° C., the color changes from blue to colorless, and the same color change is exhibited even when cooled from this state.

Example 8 (See FIG. 4) A colorless printed matter cooled to 14 ° C. or lower was heated to a temperature higher than the complete melting temperature (T ₁ : 44 ° C.) at which the component (c) melts, and then cooled. The color begins to develop at a temperature lower than the color development start temperature (T ₂ : 36 ° C.), and the blue-green color gradually becomes darker. At the full color development temperature (T ₃ : 24 ° C.), the blue-green color becomes the highest and the maximum color density becomes Present. The blue-green color gradually decreases as the cooling is further performed, and returns to a colorless state when the temperature becomes lower than the complete decoloring temperature (T ₄ : 14 ° C.). When heated to 44 ° C. or higher again, the same color change is repeatedly exhibited reversibly. still,
When heated again from the complete melting temperature (T ₁ : 44 ° C.) or more in the process of cooling from 36 ° C. to 14 ° C., the color changes from blue-green to colorless, and the same color change is reversible even when cooled from this state. To occur.

Example 10 (see FIG. 5) A colorless printed matter cooled to 2 ° C. or lower was heated to a temperature higher than the complete melting temperature (T ₁ : 36 ° C.) at which the component (c) melts, and then cooled to develop color. The color starts to develop at a temperature lower than the starting temperature (T ₂ : 30 ° C.), and the orange color gradually becomes darker. At the full color developing temperature (T ₃ : 15 ° C.), the orange color becomes darkest and exhibits the maximum color density. The orange color gradually becomes darker as it is further cooled, and returns to a colorless state when the temperature becomes lower than the complete decoloring temperature (T ₄ : 2 ° C.). When heated again to 36 ° C. or higher, the same color change is repeatedly and reversibly generated. In the course of cooling from 30 ° C. to 2 ° C., the complete melting temperature (T ₁ :
When heated above 36 ° C.), the color changes from orange to colorless, and the same color change occurs reversibly when cooled from this state.

Example 19 (See FIG. 6) A colorless printed matter cooled to 8 ° C. or lower was heated to a temperature equal to or higher than the complete melting temperature (T ₁ : 46 ° C.) at which the component (c) was melted, and then cooled to develop color. The color begins to develop at a temperature below the starting temperature (T ₂ : 37 ° C.), and the pink color gradually becomes darker.
At the full color development temperature (T ₃ : 34 ° C.), the pink color becomes darkest and exhibits the maximum color development density. As the color is further cooled, the pink color gradually becomes darker, and when the temperature falls below the complete decoloring temperature (T ₄ : 8 ° C.), the colorless state is restored. When heated again to 46 ° C. or higher, the same color change is repeatedly and reversibly generated.
In addition, when the mixture is heated to a temperature equal to or higher than the complete melting temperature (T ₁ : 46 ° C.) again during the process of cooling from 46 ° C. to 2 ° C., the color changes from pink to colorless. Reversibly occurs.

Example 20 (See FIG. 7) A colorless printed matter cooled to 20 ° C. or lower was heated to a temperature equal to or higher than the complete melting temperature (T ₁ : 44 ° C.) at which the component (c) was melted, and then cooled to develop color. The color starts to develop at a temperature lower than the starting temperature (T ₂ : 38 ° C.), the pink color gradually becomes darker, and the pink color becomes darkest at the full color developing temperature (T ₃ : 35 ° C.), and exhibits the maximum color density. . As it cools further, the pink color gradually becomes darker, and the complete decoloring temperature (T ₄ : 20)
When the temperature falls below (° C), the colorless state is restored. When heated again to 44 ° C. or higher, the same color change is repeatedly and reversibly generated. In addition, when the mixture is heated again from the complete melting temperature (T ₁ : 44 ° C.) or more in the process of cooling from 44 ° C. to 20 ° C., the color changes from pink to colorless. Reversibly occurs.

Example 21 (see FIG. 8) A colorless printed matter cooled to 16 ° C. or lower was heated to a temperature equal to or higher than the complete melting temperature (T ₁ : 40 ° C.) at which the component (c) melts, and then cooled to develop color. Color development starts at a temperature equal to or lower than the starting temperature (T ₂ : 36 ° C.), the pink color gradually becomes deeper, and at the full color developing temperature (T ₃ : 27 ° C.), the pink color becomes deepest and exhibits the maximum color density. . Note that the color density in the state where the maximum color density was shown was higher than the color density in the state where the composition of Example 20 exhibited the maximum color density. As the color is further cooled, the pink color gradually becomes darker, and when the temperature becomes lower than the complete decoloring temperature (T ₄ : 16 ° C.), the color returns to a colorless state. When heated again to 40 ° C. or higher, the same color change is repeatedly and reversibly generated. During the process of cooling from 40 ° C. to 16 ° C., the complete melting temperature (T ₁ : 40)
(° C.) or more, the color changes from pink to colorless, and the same color change occurs reversibly when cooled from this state.

[0043]

The reversible thermochromic composition of the present invention is triggered by a temperature rise by heating from a decolored state, starts color development in a temperature decreasing process after heating, exhibits a color development state of a maximum color density, and is decolorized. It exhibits a unique reversible thermochromic behavior that returns to a state, provides discoloration characteristics not found in conventional thermochromic compositions, and is used in a variety of fields, such as thermometer materials, temperature detection materials, anti-counterfeiting, training elements, toys, decoration, etc. Applied to satisfy the specificity. Especially in the toy field, since the color development state can be easily brought out by thermal means slightly higher than the living temperature range, it is possible to satisfy the unexpectedness and taste of change, and
Productivity can be enhanced in combination with the reversible color reproduction function. Furthermore, the change can be diversified by using in combination with a conventional heat-decoloring type thermochromic composition.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a graph showing a temperature-color density curve of the reversible thermochromic composition of the present invention.

FIG. 2 shows the temperature of Example 2 of the reversible thermochromic composition of the present invention.
FIG. 4 is an explanatory diagram of a graph showing a color density curve.

FIG. 3 shows the temperature of Example 4 of the reversible thermochromic composition of the present invention.
FIG. 4 is an explanatory diagram of a graph showing a color density curve.

FIG. 4 shows the temperature of Example 8 of the reversible thermochromic composition of the present invention.
FIG. 4 is an explanatory diagram of a graph showing a color density curve.

FIG. 5 is an explanatory diagram of a graph showing a temperature-color density curve of Example 10 of the reversible thermochromic composition of the present invention.

FIG. 6 is an explanatory diagram of a graph showing a temperature-color density curve of Example 19 of the reversible thermochromic composition of the present invention.

FIG. 7 is an explanatory diagram of a graph showing a temperature-color density curve of Example 20 of the reversible thermochromic composition of the present invention.

FIG. 8 is an explanatory diagram of a graph showing a temperature-color density curve of Example 21 of the reversible thermochromic composition of the present invention.

FIG. 9 is an explanatory diagram of a graph showing a temperature-color density curve of a conventional reversible thermochromic composition.

[Explanation of symbols]

T ₁ complete melting temperature T ₂ color initiation temperature T ₃ complete coloring temperature T ₄ complete decoloring temperature

Claims (6)

[Claims] Claims: 1. A reversible thermochromic composition which develops and decolors by an electron transfer reaction, in which a temperature rise due to heating from a decolored state is used as a trigger to start coloring in a temperature decreasing process after heating.
A reversible thermochromic composition having a reversible color-changing function for returning to a decolored state after developing a color-developed state having a maximum color-developing density. (2) an electron-donating color-forming organic compound,
(B) an electron-accepting compound selected from the alkoxyphenol compounds represented by the following general formula (1): (c) a reaction medium that reversibly causes the electron transfer reaction according to (a) and (b) in a specific temperature range. With the compound as an essential component, the temperature is raised by heating from the decolored state as a trigger, color development is started in the temperature decreasing process after heating, the color developed state of the maximum color density is developed, and then returned to the decolored state The reversible thermochromic composition according to claim 1, which has a reversible color changing function. Embedded image (R represents an alkyl group.) 3. The reversible thermochromic composition according to claim 2, wherein the alkyl group of the alkoxyphenol compound represented by the general formula (1) is a linear or branched alkyl group having 3 to 18 carbon atoms. 4. In the component (c), chain hydrocarbons,
The reversible thermochromic composition according to claim 2, comprising one or more compounds selected from alicyclic hydrocarbons, aromatic hydrocarbons, and halogenated hydrocarbons. 5. The method according to claim 2, wherein the microcapsules are included.
A reversible thermochromic composition according to any one of claims 1 to 4. 6. The reversible thermochromic composition according to claim 2, wherein the heating temperature is a temperature not lower than the melting point of the compound (c).