JP2002129056A - Microcapsule pigment having reversible heat-discoloring property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microcapsule pigment having a reversible heat-discoloring property, which is capable of finely adjusting a discoloring temperature and is applied in various fields of such as temperature-displaying, decorating, toys, training elements and the like. SOLUTION: The microcapsule pigment having a reversible heat-discoloring property, has in a microcapsule, essential four components composed of (a) an organic compound having electron-donating and coloring property, (b) an electron-acceptable compound, (c) a reaction medium to determine the temperature in occurring of coloring reaction of the above (a) and (b), and (d) an acrylic-polymerized aromatic hydrocarbon resin as an agent for adjusting discoloring temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reversible thermochromic microcapsule pigment. More specifically, the present invention relates to a microcapsule pigment containing a composition that changes color reversibly by a change in temperature.

[0002]

2. Description of the Related Art Heretofore, reversible thermal discoloration in which color erasure is started in a temperature rising process from a color-developing state, a complete color erasure state is exhibited at a specific temperature or higher, and color development is started in a subsequent temperature lowering process and returned to a color-developed state. Several proposals have been disclosed for compositions that exhibit properties. The composition can be broadly classified into two types. The first type is discolored before and after the discoloration temperature, and only one specific state exists in the normal temperature range between the two states before and after the discoloration. I can't do it. That is, the other state is maintained while the heat or cold required for the state to develop is applied, but returns to the original state exhibited in the normal temperature range when the application of the heat or cold is stopped. A relatively small hysteresis width (ΔH) with respect to the color density curve
Is a reversible thermochromic composition that changes color (for example,
JP-B-51-44706, JP-B-1-29398
No.).

In the second type, the color changes along a route that is significantly different between a case where the temperature is increased from a temperature lower than the color change temperature range and a case where the temperature is decreased from a temperature higher than the color change temperature range. The color changes due to a large hysteresis width (ΔH) with respect to the temperature-color density curve, and even after removing the application of the heat or cold required for the color change, the temperature changes in the temperature range between the low-temperature trigger and the high-temperature trigger. It is a thermosensitive color-changing color memory composition capable of alternately storing and retaining colors discolored below the low-temperature trigger or above the high-temperature trigger (Japanese Patent Publication No. 4-17154, JP-A-7-33997).
JP, JP-A-7-179777, JP-A-8-3
No. 9936). Although the above-mentioned composition has different hysteresis widths (ΔH), it exhibits discoloration behavior as shown in the temperature-color density curve of FIG. The discoloration behavior is:
(B) Determines the temperature at which a color reaction between the electron-donating color-forming organic compound and (b) the electron-accepting compound takes place. (C) It is specified depending on the reaction medium.

[0004]

The above-mentioned (c) compounds which are effective as a reaction medium are limited in kind, and in a system to which an effective compound is applied, the temperature-color density curve is shifted to a higher temperature side. There is no means for causing the color change temperature to be delicately adjusted, and the intended color change characteristics are not always satisfied. The present inventors have made intensive studies on the reversible thermochromic composition, and found that by blending a specific compound as the fourth component, the temperature-color density curve was slightly displaced, and the present invention was found. Completed. The present invention provides a reversible thermochromic microcapsule pigment having a controlled color change temperature based on the conventional (a), (b), and (c) three-component color change characteristics. It is applicable to various fields such as temperature display, decoration, toys, teaching material elements, etc.

[0005]

The present invention relates to (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound,
(C) A reaction medium for determining the temperature at which the color reaction between (a) and (b) occurs, and (d) four essential components of an acrylic copolymerized aromatic hydrocarbon resin as a color change temperature regulator in microcapsules. A reversible thermochromic microcapsule pigment is required. Further, the (d) discoloration temperature adjuster has an average molecular weight of 2000 to 70000, and
An acrylic styrene copolymer resin having a softening point of 50 to 200 ° C., and (d) the discoloration temperature regulator is contained in an amount of 0.02 to 0.3 parts by weight based on 1 part by weight of the reaction medium. A reversible thermochromic microcapsule pigment having a particle diameter in the range of 0.01 to 6 μm, and exhibiting a hysteresis width (ΔH) of 5 ° C. or less with respect to a temperature-color density curve, and discoloring. And so on.

The following is a reversible thermochromic microcapsule pigment.
Characteristics of Color Density-Temperature Curve
explain in detail. In FIG. 1, the vertical axis represents color density, and the horizontal axis represents
Temperature is indicated. Changes in color density due to temperature changes are indicated by arrows.
Follow the signs. Here, A reaches a completely decolored state
Minimum temperature T_Four (Hereinafter referred to as complete decolorization temperature)
This is a point indicating the density, and B is the maximum that can maintain a complete coloration state.
High temperature T_Three (Hereinafter referred to as decolorization start temperature)
Where C is the lowest temperature at which a complete decolored state can be maintained.
Degree T_Two (Hereinafter referred to as the color development start temperature)
Where D is the maximum temperature T at which a full color state is reached. ₁ 
(Hereinafter referred to as complete color temperature)
is there. Temperature T_A In the coloration state E point and the decoloration state F point
Are in a state where both phases coexist._A Including, presenting
Discoloration can be maintained in the temperature range where the color state and the decolored state can coexist
Temperature range, the length of the line segment EF is discolored contrast
And the length of the line segment HG passing through the midpoint of the line segment EF
Is the temperature range that indicates the degree of hysteresis (hereinafter referred to as hysteresis).
Cis width ΔH), and this ΔH value is small (5 ° C.
Less than one of the two conditions before and after discoloration at room temperature
Only the state of can exist. Further, the ΔH value is large.
(5 ° C. to 80 ° C.) and each state before and after discoloration can be easily maintained.
You. In particular, reversible thermal discoloration with a small ΔH value (less than 5 ° C.)
Functional compositions are used as indicators due to their discoloration properties.
The adjustment of the discoloration temperature is important.

According to the present invention, the discoloration point on the low temperature side is shifted to the high temperature side by finely adjusting the discoloration point by blending an acrylic copolymerized aromatic hydrocarbon resin as a component (d) as a discoloration temperature regulator. What you can do. Explaining this point, by blending the component (d), T ₁ (complete color development temperature) and T ₂ (color development start temperature) are shifted to the higher temperature side as shown by the broken line of the color density-temperature curve in FIG. shift.
The shifting temperature can be arbitrarily adjusted by the component (d), that is, the type and amount of the discoloring temperature adjusting agent.

Further, the reversible thermochromic composition is used as a reversible thermochromic microcapsule pigment encapsulated in microcapsules to obtain a chemically and physically stable reversible thermochromic material. When the color-changing composition is encapsulated in microcapsules, depending on the particle size distribution of the capsule particle size, a color tone change due to a temperature change, particularly a color developing behavior at the time of a temperature drop occurs. This is approximately 1 to 50 μm, preferably 1 to 30 μm, although it varies depending on the application when producing the microcapsule pigment.
Although the microcapsule pigment having a particle size of is used, the particle size varies, and not all the microcapsule pigments exhibit the particle size in the above range. There are also microcapsule pigments that have The microcapsule pigment having a particle size of about 0.01 to 3 μm can be applied to process printing inks and writing implement inks by high mesh decomposition,
(C) Due to the supercooling property of the components, as shown by the solid line of the color density-temperature curve in FIG. When the temperature of the microcapsule pigment decreases, the color shifts to a lower temperature of 2 to 30 ° C. than the temperature at which the color develops, or the color gradually develops so that no sharp discoloration is exhibited and the original discoloration characteristics are hardly obtained. However, by blending the component (d) into the microcapsule pigment having a small particle size, the cloud point of the reversible thermochromic composition is increased, and the crystallinity of the composition itself is improved, whereby (c) 3) By suppressing the supercooling property of the components
Color Concentration - show good color behavior sensitively colored with as indicated by the dashed temperature curve T ₁ (complete coloring temperature) and T ₂ (coloring starting temperature) is shifted to the high temperature side.

The component (d) will be described. As the acrylic copolymerized aromatic hydrocarbon resin as the component (d), specifically, an acrylic styrene copolymerized resin [manufactured by Sanyo Chemical Co., Ltd., trade names: Hymer SBM100, Hymer S
BM73F].

[0010] The (d) discoloration temperature adjuster is added in an amount of 0.01 to 0.3 part by weight, preferably 0.01 to 0.2 part by weight, per 1 part by weight of the component (c). You. 0.
If the amount is less than 01 parts by weight, it is difficult to exhibit a desired discoloration temperature adjusting effect, and if it exceeds 0.3 parts by weight, the discoloration sensitivity is liable to be impaired, and it is difficult to exhibit sharp discoloration behavior.

The above-mentioned (a) the electron-donating color-forming organic compound includes conventionally known diphenylmethanephthalides,
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.

As the electron accepting compound of the component (b), a group of compounds having an active proton, a group of pseudo-acidic compounds [not an acid, but a compound which acts as an acid in the composition to form a color of the component (a)] Group], and a compound group having electron vacancies. When the compound having an active proton is exemplified, the compound having a phenolic hydroxyl group includes monophenols to polyphenols, and further, as a substituent thereof, an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group, a carboxy group and an ester thereof. Or those having an amide group, a halogen group, etc., and bis-type,
Examples thereof include phenol-aldehyde condensation resins such as tris-type phenol. Further, a metal salt of the compound having a phenolic hydroxyl group may be used.

Specific examples will be described below. Phenol, o-
Cresol, tert-butylcatechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, 4- (4- (1-methylethoxyphenyl) Sulfonylphenol, 4- (4-butyloxyphenyl) sulfonylphenol, 4- (4-pentyloxyphenyl) sulfonylphenol, 4- (4-hexyloxyphenyl) sulfonylphenol, 4- (4-heptyloxyphenyl) sulfonylphenol , 4- (4-octyloxyphenyl) sulfonylphenol, n-butyl p-hydroxybenzoate, n-octyl p-hydroxybenzoate, resorcinol, dodecyl gallate, 2,2
-Bis (4-hydroxyphenyl) propane, 4,4-
Dihydroxydiphenyl sulfone, 1,1-bis (4-
(Hydroxyphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, 1-phenyl-1,1
-Bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -3-methylbutane,
1,1-bis (4-hydroxyphenyl) -2-methylpropane, 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-bis (4-hydroxyphenyl) n-dodecane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) ethyl propionate, 2,2-bis (4 -Hydroxyphenyl) -4-methylpentane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane,
There are 2,2-bis (4-hydroxyphenyl) n-heptane, 2,2-bis (4-hydroxyphenyl) n-nonane, and the like. Although the compound having the phenolic hydroxyl group can exhibit the most effective thermochromic properties,
Their metal salts, aromatic carboxylic acids and C2-5
Aliphatic carboxylic acids and their metal salts, carboxylic acid metal salts, acidic phosphoric acid esters and their metal salts,
A compound selected from 2,3-triazole and a derivative thereof may be used. Furthermore, a fluoroalcohol compound can also be used, and is exemplified below. 2-hydroxyhexafluoroisopropylbenzene, 1,3-bis (2-hydroxyhexafluoroisopropyl) benzene, 1,4-bis (2-hydroxyhexafluoroisopropyl) benzene, 1,3-bis (2-hydroxymethyl-hexa) Fluoroisopropyl) benzene, 1,3
-Bis (3-hydroxy-1,1-bistrifluoromethylpropyl) benzene, 1,4-bis (2-hydroxymethyl-hexafluoroisopropyl) benzene,
There are 1,4-bis (3-hydroxy-1,1-bistrifluoromethylpropyl) benzene, 2-hydroxymethyl-hexafluoroisopropylbenzene, 3-hydroxy-1,1-bistrifluoromethylpropylbenzene, and the like.

Although the reversible thermochromic composition of the present invention comprising the two components (a) and (b) can provide reversible heat coloring, it is limited to the adjustment of the discoloration temperature. By using the component (c), the discoloration temperature can be adjusted practically. (C) The above (a),
Compounds which are reaction media for causing the electron transfer reaction according to (b) to occur reversibly in a specific temperature range include hydrocarbons, halogenated hydrocarbons, sulfides, ethers, ketones, esters, and acid amides. Conventionally, general-purpose reaction media such as alcohols and waxes are all effective, and semi-liquid substances such as medium molecular weight polymers may be used. 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.

The sulfides include di-n-octyl sulfide, di-n-nonyl sulfide, di-n-decyl sulfide, di-n-dodecyl sulfide, di-n-
Tetradecyl sulfide, di-n-hexadecyl sulfide, di-n-octadecyl sulfide, octyldodecyl sulfide, diphenyl sulfide, dibenzyl sulfide, ditolyl sulfide, diethyl phenyl sulfide, dinaphthyl sulfide, 4,4'-dichloro-
Examples thereof include diphenyl sulfide and 2,4,5,4'-tetrachloro-diphenyl sulfide.

Examples of the ethers include aliphatic ethers having 10 or more carbon atoms, such as dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, didodecyl ether, and the like. 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, undecanediol diethyl ether, etc. . Alicyclic ethers such as s-trioxane; As aromatic ethers, phenyl ether, benzyl phenyl ether, dibenzyl ether, di-p
-Tolyl ether, 1-methoxynaphthalene, 3,4
Examples thereof include 5-trimethoxytoluene.

Examples of the ketones include aliphatic ketones having a total carbon number of 10 or more, for example, 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, 5-undecanone, 6-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,
-Octadecanone, 2-nonadecanone, 10-nonadacanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, lauron, stearone and the like. 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-octylacetophenone, n-nonanophenone, 4-n-heptylacetophenone, n-octanophenone, 4 -N-hexylacetophenone, 4-n-
Cyclohexyl acetophenone, 4-tert-butyl propiophenone, n-heptaphenone, 4-n-pentyl acetophenone, cyclohexyl phenyl ketone,
Benzyl-n-butyl ketone, 4-n-butylacetophenone, n-hexanophenone, 4-isobutylacetophenone, 1-acetonaphthone, 2-acetonaphthone,
Cyclopentyl phenyl ketone and the like. Aryl aryl ketones, for example, benzophenone, benzyl phenyl ketone, dibenzyl ketone and the like. Alicyclic ketones, for example, cyclooctanone, cyclododecanone, cyclopentadecanone, 4-tert-butylcyclohexanone and the like can be exemplified.

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,
Stearyl caprate, docosyl caprate, 2-ethylhexyl laurate, n-decyl laurate, 3-methylbutyl myristate, cetyl myristate, isopropyl palmitate, neopentyl palmitate, nonyl palmitate, cyclohexyl palmitate, n-stearate Butyl, 2-methylbutyl stearate, 3,5,5-trimethylhexyl stearate, n-undecyl stearate, pentadecyl stearate, stearyl stearate, cyclohexyl methyl stearate, isopropyl behenate, hexyl behenate, lauryl behenate, Behenyl behenate, cetyl benzoate, p-
tert-butyl stearyl benzoate, dimyristyl phthalate, distearyl phthalate, dimyristyl oxalate, dicetyl oxalate, dicetyl malonate, dilauryl succinate, dilauryl glutarate, diundecyl adipate, dilauryl azelate, di-lauryl sebacate (n −
Nonyl), dineopentyl 1,18-octadecylmethylenedicarboxylate, ethylene glycol dimyristate, propylene glycol dilaurate, propylene glycol distearate, hexylene glycol dipalmitate, 1,5-pentanediol dimyristate,
1,2,6-hexanetriol trimiristate,
Examples thereof include 1,4-cyclohexanediol didecyl, 1,4-cyclohexane dimethanol dimyristate, xylene 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.

Furthermore, the 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-undersi eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate, n-nonyl behenate , N-undecyl behenate,
Examples include n-tridecyl behenate and n-pentadecyl behenate.

Examples of the alcohols include saturated aliphatic monohydric alcohols such as decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol and octadecyl alcohol. , Eicosyl alcohol,
Docosyl alcohol and the like. Aliphatic unsaturated alcohols such as allyl alcohol and oleyl alcohol; Cycloaliphatic alcohols, for example, cyclopentanol, cyclohexanol, cyclooctanol, cyclododecanol,
4-tert-butylcyclohexanol and the like. Aromatic alcohols, for example, 4-methylbenzyl alcohol, benzhydrol and the like. Polyhydric alcohols, such as polyethylene glycol, can be exemplified.

As the acid amides, the following compounds can be exemplified. Acetamide, propionamide, butyric amide, caproic amide, caprylic amide, capric amide, lauric amide, myristic amide,
Palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, 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, N-butylamide palmitate, N-butylamide stearate, N-butylamide oleate, N-octylamide laurate, N-octylamide myristic, N-octylamide palmitate, N-stearic acid -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 amide, Trimyristic amide, Tripalmitic amide, Tristearic acid amide, Trioleic amide, Succinamide, Adipamide,
Glutaramide, malonamide, azelaic amide, maleic amide, succinic N-methylamide, adipic N-methylamide, glutaric N-methylamide, malonic N-methylamide, azelaic N-methylamide, succinic N- Ethylamide, adipic acid N-
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-octylamide , Adipic acid N
-Dodecylamide and the like.

The reversible thermochromic composition can be obtained by including the essential four components consisting of the components (a), (b), (c) and (d). In addition, (a),
The mixing ratio of the components (b) and (c) depends on the density, the discoloration temperature, the discoloration form, and the type of each component. In general, the component ratio at which a desired discoloration characteristic is obtained is (a) component 1 For
(B) component 0.1 to 50, preferably 0.5 to 20,
(C) Component is in the range of 1 to 800, preferably 5 to 200 (all the above parts are parts by weight).

Incidentally, a light stabilizer can also be contained in order to prevent light deterioration of the reversible thermochromic composition. Examples of the light stabilizer include an ultraviolet absorber, an antioxidant, and a carotene, a pigment, an amine, a phenol, a nickel complex, and a sulfide, which prevent photodeterioration caused by an excited state due to a photoreaction of the component (a). Compounds that suppress the oxidation reaction such as singlet oxygen quenchers, superoxide anion quenchers such as complexes of oxide dismutase with cobalt and nickel, and ozone quenchers.

The above-described reversible thermochromic composition is encapsulated in microcapsules and used as a microcapsule pigment. Thereby, the reversible thermochromic composition can be maintained under the same composition under various use conditions, and a chemically and physically stable pigment can be formed, and the same effect can be obtained. The microencapsulation includes conventionally known interfacial polymerization methods, in situ polymerization methods, in-liquid curing coating methods, phase separation methods from aqueous solutions, phase separation methods from organic solvents, melt dispersion cooling methods, air suspension coating. And a spray-drying method, which are appropriately selected according to the application. Further, a secondary resin film may be further provided on the surface of the microcapsule according to the purpose to impart durability, or the surface characteristics may be modified for practical use. When the reversible thermochromic composition is encapsulated in the microcapsules, the light stabilizer may be encapsulated in the microcapsules together with the reversible thermochromic composition, or used when applied as a coloring material. It can also be added in the vehicle. In addition, the light stabilizer can be included in a microcapsule and also added to a vehicle.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The reversible thermochromic microcapsule pigment of the present invention can be obtained by conventional microencapsulation means, dispersed in various vehicles and used as printing inks or paints in the form of printed matter or paint. You can get things. Also, various molded products can be obtained by blending with a molding resin by a general-purpose molding means. Further, it can be dispersed in a wax-like or paste-like medium to form a coloring material. The color change can be diversified by appropriately using a non-thermochromic dye or pigment. Examples are shown below, but the present invention is not limited to the examples.

[0028]

EXAMPLES The method for preparing the reversible thermochromic microcapsule pigments of Examples 1 to 5 will be described below. Example 1 Preparation of microcapsule pigment enclosing a reversible thermochromic composition As component (a) 3- [2-ethoxy-4- (N-ethylanilino) phenyl] -3- (1-ethyl-2-methyl-) Indole-3-yl) -4-azaphthalide 1.5
Parts by weight, 6.0 parts by weight of 2,2-bis (4-hydroxyphenyl) hexafluoropropane as the component (b),
(C) 50.0 parts by weight of neopentyl stearate as a component, and (D) an acrylic styrene copolymer resin (manufactured by Sanyo Chemical Co., Ltd., trade name: Hymer SBM100,
Average molecular weight: 15,000, softening point: 104 ° C.] A reversible thermochromic composition consisting of 5.0 parts by weight is uniformly dissolved, and as a wall material, 30.0 parts by weight of an aromatic isocyanate prepolymer and 35.0 parts by weight of ethyl acetate are used. Was added and the solution dissolved at 70 ° C. was emulsified in a 15% gelatin solution. At the time of emulsification, the stirring power of the homomixer is adjusted so that the particle size becomes 5.0 to 8.0 μm. After the emulsification, stirring is continued for about 1 hour. By weight, the mixture was further stirred for 6 hours to obtain a reversible thermochromic microcapsule pigment suspension. The microcapsule pigment was isolated from the reversible thermochromic microcapsule pigment suspension by centrifugation. The microcapsule pigment exhibits a reversible thermochromic property from blue to colorless.

Example 2 Preparation of a microcapsule pigment containing a reversible thermochromic composition The component (a) is 3- [2-ethoxy-4- (N-ethylanilino) phenyl] -3- (1-ethyl-2). -Methyl-indol-3-yl) -4-azaphthalide 1.5
Parts by weight, 6.0 parts by weight of 2,2-bis (4-hydroxyphenyl) hexafluoropropane as the component (b),
(C) 50.0 parts by weight of neopentyl stearate as a component, and (D) an acrylic styrene copolymer resin (manufactured by Sanyo Chemical Co., Ltd., trade name: Hymer SBM100,
Average molecular weight: 15,000, softening point: 104 ° C.] A reversible thermochromic composition consisting of 5.0 parts by weight is uniformly dissolved, and as a wall material, 30.0 parts by weight of an aromatic isocyanate prepolymer and 35.0 parts by weight of ethyl acetate are used. Was added and the solution dissolved at 70 ° C. was emulsified in a 15% gelatin solution. At the time of emulsification, the stirring power of the homomixer is adjusted so that the particle diameter becomes 1.0 to 2.0 μm. After the emulsification, stirring is continued for about 1 hour. By weight, the mixture was further stirred for 6 hours to obtain a reversible thermochromic microcapsule pigment suspension. The microcapsule pigment was isolated from the reversible thermochromic microcapsule pigment suspension by centrifugation. The microcapsule pigment exhibits a reversible thermochromic property from blue to colorless.

Example 3 Preparation of Microcapsule Pigment Containing Reversible Thermochromic Composition (A) 1,2-benz-6- (N-ethyl-)
N-isobutylamino) fluorane 1.0 part by weight,
As component (b), 3.0 parts by weight of 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 3.0 parts by weight of 1,1-bis (4-hydroxyphenyl) n-decane, as component (c) Stearyl caprate 40.0 parts by weight, cetyl caprate 10.0 parts by weight, low molecular weight acrylic styrene copolymer resin (manufactured by Sanyo Chemical Co., Ltd., trade name: Hymer SBM73F, average molecular weight 40000, softening point) 120 ° C.] A reversible thermochromic composition consisting of 5.0 parts by weight was uniformly dissolved, and 30.0 parts by weight of an aromatic isocyanate prepolymer and 35.0 parts by weight of ethyl acetate were added as a wall film material. Dissolve the solution
Emulsified in 15% gelatin solution. At the time of emulsification, the stirring power of the homomixer is adjusted so that the particle size becomes 1.0 to 3.0 μm. After the emulsification, stirring is continued for about 1 hour, and then the water-soluble aliphatic modified amine 2.5 By weight, the mixture was further stirred for 6 hours to obtain a reversible thermochromic microcapsule pigment suspension. The microcapsule pigment was isolated from the reversible thermochromic microcapsule pigment suspension by centrifugation. The microcapsule pigment exhibits a pink to colorless reversible thermochromic property.

Example 4 Preparation of Microcapsule Pigment Containing Reversible Thermochromic Composition (A) 3,3-bis- (2-ethoxy-4-)
1.0 parts by weight of diethylaminophenyl) 4-azaphthalide, 5.0 parts by weight of 2,2-bis (4-hydroxyphenyl) hexafluoropropane as the component (b), (c)
25.0 parts by weight of 2-methylpentyl behenate and 25.0 parts by weight of 2-ethylhexyl behenate as components;
(D) Uniformly dissolves a reversible thermochromic composition comprising 5.0 parts by weight of an acrylic styrene copolymer resin (trade name: Hymer SBM100, average molecular weight 15,000, softening point 104 ° C) manufactured by Sanyo Chemical Industries, Ltd. as a component. Then, 30.0 parts by weight of an aromatic isocyanate prepolymer and 35.0 parts by weight of ethyl acetate were added as wall material, and a solution dissolved at 70 ° C. was emulsified in a 15% gelatin solution. At the time of emulsification, the stirring power of the homomixer is adjusted so that the particle diameter becomes 2.0 to 4.0 μm. After the emulsification, stirring is continued for about 1 hour, and then the water-soluble aliphatic modified amine 2.5 By weight, the mixture was further stirred for 6 hours to obtain a reversible thermochromic microcapsule pigment suspension. The microcapsule pigment was isolated from the reversible thermochromic microcapsule pigment suspension by centrifugation. In addition, the said microcapsule pigment shows a reversible thermochromic property from blue-green to colorless.

Example 5 Preparation of Microcapsule Pigment Containing Reversible Thermochromic Composition 1.0 parts by weight of 1,3-dimethyl-6-diethylaminofluoran as component (a) and 2,2 as component (b) −
3.0 parts by weight of bis (4-hydroxyphenyl) hexafluoropropane, 3.0 parts by weight of 1,1-bis (4-hydroxyphenyl) n-decane, 50.0 parts by weight of n-heptyl stearate as a component (c) Part, low molecular weight acrylic styrene copolymer resin [Sanyo Chemical Co., Ltd.]
Product name: Hymer SBM73F, average molecular weight 400
00, softening point: 120 ° C.] A reversible thermochromic composition consisting of 5.0 parts by weight was uniformly dissolved, and 30.0 parts by weight of an aromatic isocyanate prepolymer and 3 parts of ethyl acetate were used as wall material.
5.0 parts by weight and dissolved at 70 ° C.
Emulsified in gelatin solution. At the time of emulsification, the stirring power of the homomixer is adjusted so that the particle size becomes 0.8 to 1.5 μm. After the emulsification, stirring is continued for about 1 hour, and then the water-soluble aliphatic modified amine 2.5 By weight, the mixture was further stirred for 6 hours to obtain a reversible thermochromic microcapsule pigment suspension. The microcapsule pigment was isolated from the reversible thermochromic microcapsule pigment suspension by centrifugation.
The microcapsule pigment exhibits orange to colorless reversible thermochromic properties.

Comparative Example 1 Preparation of a Microcapsule Pigment Containing a Reversible Thermochromic Composition A reversible thermochromic microcapsule pigment was prepared in the same manner as in Example 1 except that the acrylic styrene copolymer resin of Example 1 was omitted. Obtained.

Comparative Example 2 Preparation of Microcapsule Pigment Encapsulating Reversible Thermochromic Composition A reversible thermochromic microcapsule pigment was prepared in the same manner as in Example 2 except that the acrylic styrene copolymer resin of Example 2 was omitted. Obtained.

Comparative Example 3 Preparation of Microcapsule Pigment Encapsulating a Reversible Thermochromic Composition A reversible thermochromic microcapsule pigment was prepared in the same manner as in Example 3 except that the acrylic styrene copolymer resin of Example 3 was omitted. Obtained.

Comparative Example 4 Preparation of a Microcapsule Pigment Encapsulating a Reversible Thermochromic Composition A reversible thermochromic microcapsule pigment was prepared in the same manner as in Example 4 except that the acrylic styrene copolymer resin of Example 4 was omitted. Obtained.

Comparative Example 5 Preparation of Microcapsule Pigment Containing Reversible Thermochromic Composition The procedure of Example 5 was repeated except that the acrylic styrene copolymer resin of Example 5 was omitted. Obtained.

Measurement of Particle Diameter The microcapsule pigments of Examples 1 to 5 and Comparative Examples 1 to 5 were measured for particle diameter by using a laser type particle size distribution analyzer [LA-300: manufactured by Dig Co., Ltd.].

Preparation of Measurement Samples 40 parts by weight of each of the microcapsule pigments of Examples 1 to 5 and Comparative Examples 1 to 5 were added to an ethylene-vinyl acetate emulsion 60.
Using a reversible thermochromic ink dispersed in parts by weight, a circle of a predetermined size was printed on high quality paper by screen printing.

Measurement of Discoloration Temperature Each of the printed materials is set at a predetermined position of a color difference meter [TC-3600 type color difference type, manufactured by Tokyo Denshoku Co., Ltd.], and heated at a temperature range of 50 ° C. at a rate of 10 ° C./min. After cooling, each temperature was measured.

The following table shows the particle size, T ₁ (complete color development temperature), and T ₂ of the reversible thermochromic microcapsule pigments of each example.
(Coloring start temperature), T ₃ (color erasing start temperature), T ₄ (complete color erasing temperature) and ΔH (hysteresis width).

[0042]

[Table 1]

The following table shows the particle size, T ₁ (complete coloring temperature), and T ₂ of the reversible thermochromic microcapsule pigment of each comparative example.
(Color development start temperature), T ₃ (color erasure start temperature), and T ₄ (complete color erasure temperature).

[0044]

[Table 2]

The color change temperatures of the examples and comparative examples will be described below with reference to schematic diagrams. The discoloration temperature characteristic of the microcapsule pigment containing the reversible thermochromic composition of Example 1 was 13 ° C. as compared with Comparative Example 1 at T ₁ (complete coloring temperature).
From 16 ° C to 16 ° C, T ₂ (color onset temperature) from 16 ° C to 18 ° C
To show the discoloration temperature curve as shown in FIG. Example 2
The discoloration temperature characteristics of the microcapsule pigment containing the reversible thermochromic composition of Example ₁ were as follows: T ₁ (complete color development temperature) was 2 ° C. to 14 ° C., and T ₂ (color development start temperature) was 14
FIG. 3 shows a discoloration temperature curve shifted from 18 ° C. to 18 ° C. The discoloration temperature characteristic of the microcapsule pigment containing the reversible thermochromic composition of Example 3 was higher than that of Comparative Example 3 by T.
FIG. 3 shows a discoloration temperature curve in which ₁ (complete color development temperature) shifts from 8 ° C. to 21 ° C. and T ₂ (color development start temperature) shifts from 28 ° C. to 30 ° C. The discoloration temperature characteristics of the microcapsule pigment containing the reversible thermochromic composition of Example 4 are shown in Comparative Example 4.
T ₁ (complete coloring temperature) from 20 ° C. to 25 ° C.,
T ₂ (color development start temperature) shifts from 32 ° C. to 34 ° C., and shows a discoloration temperature curve as shown in FIG. The discoloration temperature characteristic of the microcapsule pigment containing the reversible thermochromic composition of Example 5 was T ₁ (complete coloring temperature) of 2 ° C. as compared with Comparative Example 5.
16 ° C. from, T ₂ (coloring starting temperature) is 20 ° C. from 18 ° C.
And shows a discoloration temperature curve as shown in FIG.

[0046]

Industrial Applicability The present invention can provide a reversible thermochromic microcapsule pigment capable of fine-tuning the color change temperature, and has applicability in various fields such as temperature display, decoration, toys, training elements, and the like.
In addition, microcapsule pigments with small particle diameters are not only finely adjusted in discoloration temperature, but also have excellent thermal discoloration function that develops sharp colors, so they can be applied to writing implement inks, spray inks, and process printing by high mesh decomposition. A reversible thermochromic microcapsule pigment that can be applied to various fields such as ink and gravure ink can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a temperature-color density curve of a microcapsule pigment containing a reversible thermochromic composition.

FIG. 2 is an illustration showing a temperature-color density curve of a reversible thermochromic microcapsule pigment of the present invention in which a low-temperature side color change point of a conventional microcapsule pigment is shifted to a high temperature side.

FIG. 3 is a graph showing a temperature-color density curve of a reversible thermochromic microcapsule pigment of the present invention in which the low-temperature side color change point of a conventional microcapsule pigment having a small particle size is shifted to a high temperature side.

[Explanation of symbols]

T ₁ complete coloring temperature T ₂ color initiation temperature T ₃ decoloring starting temperature T ₄ complete decoloring temperature T the temperature of the midpoint in color density at a temperature T _G decoloring process of the midpoint in color density in the _H coloring process ΔH hysteresis width (T _H -T _G)

Claims (5)

[Claims] (1) an electron-donating color-forming organic compound,
(B) an electron-accepting compound, (c) a reaction medium for determining the temperature at which the color reaction between (a) and (b) occurs, and (d) an acrylic copolymerized aromatic hydrocarbon resin as a color change temperature regulator A reversible thermochromic microcapsule pigment in which the essential four components are encapsulated in microcapsules. 2. The method according to claim 1, wherein (d) the discoloring temperature adjusting agent is 2,000.
Having an average molecular weight of ~ 70000 and a softening point of 50
The reversible thermochromic microcapsule pigment according to claim 1, which is an acrylic styrene copolymer resin at a temperature of from 200 to 200 ° C. 3. The reversible thermochromic microcapsule according to claim 1, wherein (d) the discoloring temperature adjusting agent is contained in an amount of 0.02 to 0.3 parts by weight based on 1 part by weight of the reaction medium. Pigment. 4. The reversible thermochromic microcapsule pigment according to claim 1, wherein the particle diameter is in the range of 0.01 to 6 μm. 5. A color change in a temperature-color density curve by showing a hysteresis width (ΔH) of 5 ° C. or less.
The reversible thermochromic microcapsule pigment according to any one of the above.