JP2023006756A - Reversible thermochromic ink composition for writing instrument and writing instrument accommodating the same - Google Patents

Abstract

To provide a reversible thermochromic ink composition excellent in durability and dispersion stability in an ink composition and capable of forming an excellent hand writing by highly combining a practical hand writing density and ink dischargeability, and a writing instrument housing the same.SOLUTION: An ink composition comprises a reversible thermochromic microcapsule pigment and a vehicle characterized in that microcapsules are obtained by enclosing a reversible thermochromic composition with a coating, wherein a volume-based average particle diameter (X) of the microcapsules is 0.1 to 3.0 μm, and an average cut sectional film thickness (Y) obtained from the following formula: cut sectional film thickness=(sectional outer periphery diameter-sectional inner periphery diameter)/2 (in the formula, the sectional outer periphery diameter and the sectional inner periphery diameter are calculated, about one microcapsule, from a circle converted diameter of an area of a region surrounded by the outer periphery of the film cross-section and an area of the region surrounded by an inner periphery of the film cross-section) is 0.02 to 1.0 μm.SELECTED DRAWING: Figure 2

Description

The present invention relates to a reversible thermochromic ink composition for writing instruments. The present invention also relates to a writing instrument containing the composition.

Conventionally, a writing instrument containing a reversible thermochromic ink composition for a writing instrument whose color tone changes with temperature change is known, and the handwriting formed using this writing instrument can be discolored by heating or rubbing, so it can be used for various purposes. widely used in

As a reversible thermochromic ink composition for writing instruments, (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, (c) the temperature at which the color reaction of the component (a) and the component (b) occurs The use of an ink composition containing a reversible thermochromic microcapsule pigment encapsulating a reversible thermochromic composition consisting of a reaction medium that determines is disclosed (see, for example, Patent Document 1).

The above-mentioned reversible thermochromic microcapsule pigment becomes discolored in a temperature range above the high temperature side discoloration point (complete discoloration temperature), and becomes colored in a temperature range below the low temperature side discoloration point (complete color development temperature). It has a thermochromic function that reversibly changes from a colored state to a decolored state by change, and can form handwriting with excellent storage stability by having a particle size within a specific range. In order for the handwriting to be good, the microcapsule pigment has durability. It is required that no deterioration occurs.

In order to improve the durability of microcapsule pigments, it is conceivable to increase the thickness of the microcapsule film (film thickness). Since the volume ratio of the inclusions decreases, the handwriting density tends to decrease. In addition, if the blending ratio of the microcapsule pigment is increased so as not to lower the handwriting density, the dispersion stability of the microcapsule pigment in the ink tends to decrease, and the ink dries at the tip of the writing instrument (pen tip). There was a tendency for poor writing to occur more easily.
On the other hand, by increasing the film thickness while maintaining the volume ratio of the inclusions, the handwriting density is maintained, but the particle size increases, so the dispersion stability of the microcapsule pigment in the ink and the pen tip of the writing instrument There was a tendency that the ink jettability of the ink tended to be lowered.

Japanese Patent Application Laid-Open No. 2006-335848

In the present invention, a reversible thermochromic microcapsule pigment is excellent in durability and dispersion stability in an ink composition, and furthermore, exhibits practical handwriting density and ink ejection stability as a writing instrument to produce good handwriting. To provide a formable reversible thermochromic ink composition for writing instruments and a writing instrument containing the same.

The reversible thermochromic ink composition for writing instruments according to the present invention is
(b) an electron-donating color-forming organic compound,
(b) an electron-accepting compound, and (c) a reaction medium that reversibly causes an electron transfer reaction between components (a) and (b) in a specific temperature range, and is coated with a reversible thermochromic composition. a reversible thermochromic microcapsule pigment comprising encapsulated microcapsules;
A reversible thermochromic ink composition for a writing instrument comprising a vehicle,
The volume-based average particle diameter (X) of the microcapsules is 0.1 to 3.0 μm, and
A cross section of the frozen microcapsule pigment was observed with a transmission electron microscope, and the following formula was obtained for all capsules within the observation field:
Cut cross-section film thickness = (cross-section outer diameter - cross-section inner diameter) / 2
(In the formula, the cross-sectional outer circumference diameter and the cross-sectional inner circumference diameter are the area of the area surrounded by the outer circumference of the coating cross section and the area of the area surrounded by the inner circumference of the coating cross section for one microcapsule. (calculated from
The average thickness of the cut cross-section obtained by the above-mentioned microcapsules is 0.02 to 0.7 μm when the average value thereof is taken as the average thickness of the cross-section.

A writing instrument according to the present invention contains the reversible thermochromic ink composition for writing instruments.

The ink composition according to the present invention uses a reversible thermochromic microcapsule pigment containing microcapsules having a volume-based average particle size and an average cross-sectional film thickness in specific ranges, respectively. Microcapsule pigments are excellent in durability against external forces and stimuli, and in dispersion stability in ink compositions. Furthermore, the writing instrument containing the ink composition according to the present invention exhibits the excellent characteristics of being able to form good handwritings while maintaining both practical handwriting density and ink ejection property at a high level.

1 is a graph for explaining hysteresis characteristics in a color density-temperature curve of a heat-erasable reversible thermochromic composition. 1 is a graph for explaining hysteresis characteristics in a color density-temperature curve of a heat color-erasable reversible thermochromic composition having color memory properties. 1 is a graph for explaining hysteresis characteristics in a color density-temperature curve of a reversible thermochromic composition of heat coloring type.

A reversible thermochromic ink composition for writing instruments according to the present invention (hereinafter sometimes referred to as "ink composition") comprises a reversible thermochromic microcapsule pigment and a vehicle. Each component constituting the ink composition according to the present invention will be described below.

The ink composition according to the present invention contains a reversible thermochromic microcapsule pigment (hereinafter sometimes referred to as "microcapsule pigment") as a colorant.

The microcapsule pigment used in the ink composition according to the present invention comprises microcapsules encapsulating the reversible thermochromic composition, and is typically an aggregate of microcapsules. As the reversible thermochromic composition, (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, (c) the temperature at which the color reaction of the component (a) and the component (b) occurs is It can be used for a reversible thermochromic composition of a heat decoloring type (discoloring by heating and developing color by cooling) containing at least three essential components of the reaction medium to be determined.

Examples of reversible thermochromic compositions to which such microcapsule pigments can be applied are described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, etc. In addition, it changes color before and after a predetermined temperature (color change point) as a boundary, exhibits a discolored state in a temperature range above the high temperature side color change point, and a color development state in a temperature range below the low temperature side color change point. Only one particular state exists in a region and the other state is maintained as long as the heat or cold required to bring about the state is applied, but when the application of heat or cold is removed A composition having a relatively small hysteresis width (ΔH) (ΔH=1 to 7° C.) that returns to the state exhibited in the normal temperature range can be mentioned (see FIG. 1).

Further, other examples of reversible thermochromic compositions to which such microcapsule pigments can be applied include JP-B-4-17154, JP-A-7-179777 and JP-A-7-33997. , JP-A-8-39936, JP-A-2005-1369, etc. show characteristics with a large hysteresis width (ΔH = 8 to 70 ° C.), and a curve plotting changes in color density due to temperature changes. When the temperature is raised from the lower temperature side than the color change temperature range, and when the temperature is lowered from the higher temperature side than the color change temperature range, the color changes along a significantly different path, and the color changes when the complete color temperature t is ₁ or less. The color development state in the temperature range or the color disappearance state in the high temperature range of the complete color disappearance temperature t ₄ or higher is the specific temperature range [the temperature range between the color development start temperature t ₂ and the color disappearance start temperature t ₃ (substantially two-phase (holding temperature range)] can also be used (see FIG. 2).

[Microcapsule pigment]
Each (a) component, (b) component, and (c) component will be specifically described below.
Component (a), that is, an electron-donating color-developing organic compound is a component that determines color, and is a compound that provides electrons to component (b), which is a color developer, to develop color.

Electron-donating color-developing organic compounds include phthalide compounds, fluoran compounds, stilinoquinoline compounds, diazarhodamine lactone compounds, pyridine compounds, quinazoline compounds, and bisquinazoline compounds. preferable.

Examples of phthalide compounds include diphenylmethanephthalide compounds, phenylindolylphthalide compounds, indolylphthalide compounds, diphenylmethaneazaphthalide compounds, phenylindolylazaphthalide compounds, derivatives thereof, and the like. Among them, phenylindolylazaphthalide compounds and derivatives thereof are preferred.
Examples of fluoran compounds include aminofluoran compounds, alkoxyfluoran compounds, derivatives thereof, and the like.

Compounds that can be used as the component (a) are exemplified below.
3,3-bis(4-dimethylaminophenyl)-6-dimethylaminophthalide,
3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide,
3,3-bis(1-n-butyl-2-methylindol-3-yl)phthalide,
3,3-bis(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide,
3-(2-ethoxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide,
3-(2-n-hexyloxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide,
3-[2-ethoxy-4-(N-ethylanilino)phenyl]-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide,
3-(2-acetamido-4-diethylaminophenyl)-3-(1-propyl-2-methylindol-3-yl)-4-azaphthalide,
3,6-bis(diphenylamino)fluorane,
3,6-bis(N-phenyl-Np-tolylamino)fluorane,
3,6-dimethoxyfluorane,
3,6-di-n-butoxyfluorane,
2-methyl-6-(N-ethyl-Np-tolylamino)fluorane,
3-chloro-6-cyclohexylaminofluorane,
2-methyl-6-cyclohexylaminofluorane,
2-chloroamino-6-di-n-butylaminofluorane,
2-(2-chloroanilino)-6-di-n-butylaminofluorane,
2-(3-trifluoromethylanilino)-6-diethylaminofluorane,
2-(3-trifluoromethylanilino)-6-di-n-pentylaminofluorane,
2-dibenzylamino-6-diethylaminofluorane,
2-(N-methylanilino)-6-(N-ethyl-Np-tolylamino)fluorane,
1,3-dimethyl-6-diethylaminofluorane,
2-chloro-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-diethylaminofluorane,
2-anilino-3-methoxy-6-diethylaminofluorane,
2-anilino-3-methyl-6-di-n-butylaminofluorane,
2-anilino-3-methoxy-6-di-n-butylaminofluorane,
2-xylidino-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-(N-ethyl-Np-tolylamino)fluorane,
6-diethylamino-1,2-benzofluorane,
6-(N-ethyl-N-isobutylamino)-1,2-benzofluorane,
6-(N-ethyl-N-isopentylamino)-1,2-benzofluorane,
2-(3-methoxy-4-dodecoxystyryl)quinoline,
2-diethylamino-8-diethylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one,
2-di-n-butylamino-8-di-n-butylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran] -3′-on,
2-di-n-butylamino-8-diethylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one ,
2-di-n-butylamino-8-(N-ethyl-N-isoamylamino)-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H) -isobenzofuran]-3'-one,
2-di-n-butylamino-8-di-n-pentylamino-4-methylspiro[5H-[1]benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran] -3′-on,
4,5,6,7-tetrachloro-3-(4-dimethylamino-2-methoxyphenyl)-3-(1-n-butyl-2-methylindol-3-yl)-1(3H)-iso benzofuranone,
4,5,6,7-tetrachloro-3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone,
4,5,6,7-tetrachloro-3-(4-diethylamino-2-ethoxyphenyl)-3-(1-n-pentyl-2-methylindol-3-yl)-1(3H)-isobenzo Furanones,
4,5,6,7-tetrachloro-3-(4-diethylamino-2-methylphenyl)-3-(1-ethyl-2-methylindol-3-yl)-1(3H)-isobenzofuranone,
3′,6′-bis[phenyl(2-methylphenyl)amino]spiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one,
3′,6′-bis[phenyl(3-methylphenyl)amino]spiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one,
3′,6′-bis[phenyl(3-ethylphenyl)amino]spiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one,
2,6-bis(2'-ethyloxyphenyl)-4-(4'-dimethylaminophenyl)pyridine,
2,6-bis(2′,4′-diethyloxyphenyl)-4-(4′-dimethylaminophenyl)pyridine,
2-(4′-dimethylaminophenyl)-4-methoxyquinazoline,
4,4'-ethylenedioxy-bis[2-(4-diethylaminophenyl)quinazoline]

As the fluoranes, in addition to compounds having a substituent on the phenyl group forming the xanthene ring, a substituent on the phenyl group forming the xanthene ring and a substituent on the phenyl group forming the lactone ring (e.g. , an alkyl group such as a methyl group, a halogen atom such as a chlorine atom, etc.) and exhibiting a blue or black color.

Component (b), that is, an electron-accepting compound, is a compound that receives electrons from component (a) and functions as a color developer for component (a).
The electron-accepting compounds include a group of compounds having an active proton, a group of pseudo-acidic compounds [a group of compounds that are not acids but act as acids in the reversible thermochromic composition to develop the color of component (a)], and electron A compound selected from a group of compounds having vacancies can be mentioned. Among the components (b) above, compounds selected from the group of compounds having an active proton are preferred.

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

Among the above components (b), a compound having a phenolic hydroxyl group is preferred because it can more effectively exhibit thermochromic properties.
Compounds having a phenolic hydroxyl group include a wide range of monophenol compounds to polyphenol compounds, and further include bisphenol compounds, trisphenol compounds, phenol-aldehyde condensed resins, and the like. A compound having a phenolic hydroxyl group preferably has at least two benzene rings. Moreover, the compound having a phenolic hydroxyl group may have a substituent such as an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group, a carboxy group and its ester or amide group, and a halogen atom.

Examples of metals contained in metal salts of compounds having phenolic hydroxyl groups include sodium, potassium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, lead, and molybdenum. etc. can be exemplified.

The compounds of component (b) are exemplified below.
Examples of compounds having one phenolic hydroxyl group include
phenol,
o-cresol,
m-cresol,
p-cresol,
4-ethylphenol,
4-n-propylphenol,
4-n-butylphenol,
2-tert-butylphenol,
3-tert-butylphenol,
4-tert-butylphenol,
4-n-pentylphenol,
4-tert-pentylphenol,
4-n-octylphenol,
4-tert-octylphenol,
4-n-nonylphenol,
4-n-dodecylphenol,
3-n-pentadecylphenol,
4-n-stearylphenol,
1-(4-hydroxyphenyl)decan-1-one,
4-chlorophenol,
4-bromophenol,
4-trifluoromethylphenol,
4-methylthiophenol,
4-nitrophenol,
2-phenylphenol,
4-phenylphenol,
2-benzylphenol,
2-benzyl-4-chlorophenol,
4-cumylphenol,
4-hydroxybenzophenone,
4-chloro-4'-hydroxybenzophenone,
4-fluoro-4'-hydroxybenzophenone,
4-cyclohexylphenol,
2-hydroxybenzyl alcohol,
3-hydroxybenzyl alcohol,
4-hydroxybenzyl alcohol,
4-(2-hydroxyethyl)phenol,
3-methoxyphenol,
4-ethoxyphenol,
4-n-propoxyphenol,
4-n-butoxyphenol,
4-n-heptyloxyphenol,
4-(2-methoxyethyl)phenol,
α-naphthol,
β-naphthol,
2,3-dimethylphenol,
2,4-dimethylphenol,
2,6-dimethylphenol,
2,6-di-tert-butylphenol,
2,4-dichlorophenol,
2,4-difluorophenol,
thymol,
3-methyl-4-methylthiophenol,
2-tert-butyl-5-methylphenol,
2,6-bis(hydroxymethyl)-4-methylphenol,
2,3,5-trimethylphenol,
2,6-bis(hydroxymethyl)-4-tert-octylphenol,
6-hydroxy-1,3-benzoxathiol-2-one,
2,4-bis(phenylsulfonyl)phenol,
2,4-bis(phenylsulfonyl)-5-methylphenol,
2,4-bis(4-methylphenylsulfonyl)phenol,
2-phenylphenol,
4-phenylphenol,
2,6-diphenylphenol,
3-benzylbiphenyl-2-ol,
3,5-dibenzylbiphenyl-4-ol,
4-cyano-4'-hydroxybiphenyl,
1-hydroxybenzotriazole,
1-hydroxy-5-methylbenzotriazole,
1-hydroxy-5-chlorobenzotriazole,
1-hydroxy-5-methoxybenzotriazole,
1-hydroxy-4-benzoylaminobenzotriazole,
1-hydroxy-4,5,6,7-tetrachlorobenzotriazole,
1,4-hydroxybenzotriazole,
1-hydroxy-5-nitrobenzotriazole,
1-hydroxy-5-phenylbenzotriazole,
1-hydroxy-5-benzylbenzotriazole,
1-hydroxy-5-ethylbenzotriazole,
1-hydroxy-5-n-octylbenzotriazole,
1-hydroxy-5-n-butylbenzotriazole,
n-butyl 4-hydroxybenzoate,
n-octyl 4-hydroxybenzoate,
4-hydroxybenzoic acid 2-heptadecafluorooctylethane,
benzyl 4-hydroxybenzoate,
4-hydroxybenzoic acid benzyl ester,
o-methylbenzyl 4-hydroxybenzoate,
m-methylbenzyl 4-hydroxybenzoate,
p-methylbenzyl 4-hydroxybenzoate,
p-ethylbenzyl 4-hydroxybenzoate,
4-hydroxybenzoate-p-propylbenzyl,
4-hydroxybenzoate-p-tert-butylbenzyl,
phenylethyl 4-hydroxybenzoate,
4-hydroxybenzoate-o-methylphenylethyl,
4-hydroxybenzoate-m-methylphenylethyl,
p-methylphenylethyl 4-hydroxybenzoate,
p-ethylphenylethyl 4-hydroxybenzoate,
4-hydroxybenzoate-p-propylphenylethyl,
4-Hydroxybenzoic acid-p-tert-butylphenylethyl and the like can be exemplified.

Examples of compounds having two phenolic hydroxyl groups include
Resorcinol,
2-methylresorcin,
4-n-hexylresorcin,
4-n-octylresorcin,
4-tert-octylresorcin,
4-benzoylresorcin,
4-nitroresorcin,
β-methyl resorcinate,
β-benzyl resorcinate,
2-chloro-4-pentanoylresorcin,
6-chloro-4-pentanoylresorcin,
2-chloro-4-hexanoylresorcin,
6-chloro-4-hexanoylresorcin,
2-chloro-4-propanoylresorcin,
6-chloro-4-propanoylresorcin,
2,6-dichloro-4-propanoylresorcin,
6-fluoro-4-propanoylresorcin,
2-chloro-4-phenylacetylresorcinol,
6-chloro-4-phenylacetylresorcin,
2-chloro-4-β-phenylpropanoylresorcin,
6-chloro-4-β-phenylpropanoylresorcin,
2-chloro-4-phenoxyacetylresorcin,
6-chloro-4-phenoxyacetylresorcin,
4-benzoyl-2-chlororesorcin,
6-chloro-4-m-methylbenzoylresorcin,
4-[1′,3′,4′,9′a-tetrahydro-6′-hydroxyspiro(cyclohexane-1,9′-[9H]-xanthene)-4′a-[2H]-yl]-1 , 3-benzenediol,
hydroquinone,
methyl hydroquinone,
trimethylhydroquinone,
catechol,
4-tert-butyl catechol,
1,6-dihydroxynaphthalene,
2,7-dihydroxynaphthalene,
1,5-dihydroxynaphthalene,
2,6-dihydroxynaphthalene,
2,4-dihydroxybenzophenone,
4,4′-dihydroxybenzophenone,
2,4-dihydroxy-2′-methylbenzophenone,
2,4-dihydroxy-3′-methylbenzophenone,
2,4-dihydroxy-4′-methylbenzophenone,
2,4-dihydroxy-4′-ethylbenzophenone,
2,4-dihydroxy-4′-n-propylbenzophenone,
2,4-dihydroxy-4′-isopropylbenzophenone,
2,4-dihydroxy-4′-n-butylbenzophenone,
2,4-dihydroxy-4'-isobutylbenzophenone,
2,4-dihydroxy-4′-tert-butylbenzophenone,
2,4-dihydroxy-4′-n-pentylbenzophenone,
2,4-dihydroxy-4′-n-hexylbenzophenone,
2,4-dihydroxy-4′-n-heptylbenzophenone,
2,4-dihydroxy-4′-n-octylbenzophenone,
2,4-dihydroxy-4′-n-decylbenzophenone,
2,4-dihydroxy-2',3'-dimethylbenzophenone,
2,4-dihydroxy-2',4'-dimethylbenzophenone,
2,4-dihydroxy-2',5'-dimethylbenzophenone,
2,4-dihydroxy-2',6'-dimethylbenzophenone,
2,4-dihydroxy-3′,4′-dimethylbenzophenone,
2,4-dihydroxy-3′,5′-dimethylbenzophenone,
2,4-dihydroxy-2',4',6'-trimethylbenzophenone,
2,4-dihydroxy-2'-methoxybenzophenone,
2,4-dihydroxy-3′-methoxybenzophenone,
2,4-dihydroxy-4'-methoxybenzophenone,
2,4-dihydroxy-2'-ethoxybenzophenone,
2,4-dihydroxy-4'-ethoxybenzophenone,
2,4-dihydroxy-4′-n-propoxybenzophenone,
2,4-dihydroxy-4′-isopropoxybenzophenone,
2,4-dihydroxy-4'-n-butoxybenzophenone,
2,4-dihydroxy-4'-isobutoxybenzophenone,
2,4-dihydroxy-4′-n-pentyloxybenzophenone,
2,4-dihydroxy-4′-n-hexyloxybenzophenone,
2,4-dihydroxy-4′-n-heptyloxybenzophenone,
2,4-dihydroxy-4′-n-octyloxybenzophenone,
2,4-dihydroxy-4′-n-nonyloxybenzophenone,
2,4-dihydroxy-2',3'-dimethoxybenzophenone,
2,4-dihydroxy-2',4'-dimethoxybenzophenone,
2,4-dihydroxy-2',5'-dimethoxybenzophenone,
2,4-dihydroxy-2',6'-dimethoxybenzophenone,
2,4-dihydroxy-3′,4′-dimethoxybenzophenone,
2,4-dihydroxy-3′,5′-dimethoxybenzophenone,
2,4-dihydroxy-3′,4′-diethoxybenzophenone,
2,4-dihydroxy-2',3',4'-trimethoxybenzophenone,
2,4-dihydroxy-2',3',6'-trimethoxybenzophenone,
2,4-dihydroxy-3′,4′,5′-trimethoxybenzophenone,
Examples include 2,4-dihydroxy-3',4',5'-triethoxybenzophenone.

Furthermore, as a bisphenol compound, for example,
1,1-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxyphenyl)propane,
1,1-bis(4-hydroxyphenyl)n-butane,
1,1-bis(4-hydroxyphenyl)n-pentane,
1,1-bis(4-hydroxyphenyl)n-hexane,
1,1-bis(4-hydroxyphenyl)n-heptane,
1,1-bis(4-hydroxyphenyl)n-octane,
1,1-bis(4-hydroxyphenyl)n-nonane,
1,1-bis(4-hydroxyphenyl)n-decane,
1,1-bis(4-hydroxy-3-methylphenyl)decane,
1,1-bis(4-hydroxyphenyl)n-dodecane,
1,1-bis(4-hydroxyphenyl)-2-methylpropane,
1,1-bis(4-hydroxyphenyl)-3-methylbutane,
1,1-bis(4-hydroxyphenyl)-3-methylpentane,
1,1-bis(4-hydroxyphenyl)-2,3-dimethylpentane,
1,1-bis(4-hydroxyphenyl)-2-ethylbutane,
1,1-bis(4-hydroxyphenyl)-2-ethylhexane,
1,1-bis(4-hydroxyphenyl)-3,7-dimethyloctane,
1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
1,1-bis(4-hydroxy-3-methyl)cyclohexane,
diphenolic acid,
1-phenyl-1,1-bis(4-hydroxyphenyl)methane,
2,2-bis(4-hydroxyphenyl)propane,
2,2-bis(4-hydroxyphenyl)n-butane,
2,2-bis(4-hydroxyphenyl)n-pentane,
2,2-bis(4-hydroxyphenyl)n-hexane,
2,2-bis(4-hydroxyphenyl)n-heptane,
2,2-bis(4-hydroxyphenyl)n-octane,
2,2-bis(4-hydroxyphenyl)n-nonane,
2,2-bis(4-hydroxyphenyl)n-decane,
2,2-bis(4-hydroxyphenyl)n-dodecane,
2,2-bis(4-hydroxyphenyl)-6,10,14-trimethylpentadecane,
1-phenyl-1,1-bis(4-hydroxyphenyl)ethane,
2,2-bis(4-hydroxyphenyl)methylpropionate,
2,2-bis(4-hydroxyphenyl)butyl propionate,
2,2-bis(4-hydroxy-3-methylphenyl)methylpropionate,
2,2-bis(4-hydroxyphenyl)ethyl propionate,
2,2-bis(4-hydroxyphenyl)-4-methylpentane,
2,2-bis(4-hydroxyphenyl)-4-methylhexane,
2,2-bis(4-hydroxyphenyl)hexafluoropropane,
2,2-bis(3,5-dihydroxymethyl-4-hydroxyphenyl)hexafluoropropane,
2,2-bis(4-hydroxy-3-methylphenyl)propane,
2,2-bis(4-hydroxy-3-methylphenyl)butane,
2,2-bis(4-hydroxy-3-isopropylphenyl)propane,
2,2-bis(3-sec-butylphenyl-4-hydroxy)propane,
2,2-bis(4-hydroxy-3-phenylphenyl)propane,
2,2-bis(3-tert-butyl-4-hydroxyphenyl)propane,
2,2-bis(3-fluoro-4-hydroxyphenyl)propane,
2,2-bis(3,5-dihydroxymethyl-4-hydroxyphenyl)propane,
9,9-bis(4-hydroxy-3-methylphenyl)fluorene,
1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene,
1,4-bis[2-(4-hydroxyphenyl)-2-propyl]benzene,
3,3-bis(4-hydroxyphenyl)oxindole,
3,3-bis(4-hydroxy-3-methylphenyl)oxindole,
bis(2-hydroxyphenyl)methane,
bis(2-hydroxy-5-methylphenyl)methane,
bis(2-hydroxy-3-hydroxymethyl-5-methyl)methane,
4,4′-[1,4-phenylenebis(1-methylethylidene)]bis(2-methylphenol),
1,1-bis(4-hydroxy-3-phenylphenyl)cyclohexane,
3,3-ethyleneoxydiphenol,
1,4-bis(4-hydroxybenzoate)-3-methylbenzene,
4,4″-dihydroxy-3″-methyl-p-terphenyl,
4,4″-dihydroxy-3″-isopropyl-p-terphenyl,
2,2-dimethyl-1,3-bis(4-hydroxybenzoyloxy)propane,
2,2′-biphenol,
4,4′″-dihydroxy-p-quaterphenyl,
4,4-dihydroxydiphenyl ether,
bis(4-hydroxyphenylthioethyl)ether bis(4-hydroxyphenyl)sulfone,
4-benzyloxy-4'-hydroxydiphenylsulfone,
4-(4-methylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(4-ethylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(4-n-propylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(4-isopropylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(4-n-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(4-isobutylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(4-sec-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(4-tert-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(3-methylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(3-ethylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(3-n-propylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(3-isopropylbenzyloxy)-4'-dihydroxyphenylsulfone,
4-(3-n-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(3-isobutylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(3-sec-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(3-tert-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-methylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-ethylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-n-propylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-isopropylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-n-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-isobutylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-sec-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
4-(2-tert-butylbenzyloxy)-4'-hydroxydiphenylsulfone,
2,4′-dihydroxydiphenyl sulfone,
3,4′-dihydroxydiphenyl sulfone,
4-hydroxydiphenyl sulfone,
4-methyl-4'-hydroxyphenylsulfone,
4-ethyl-4'-hydroxydiphenylsulfone,
4-n-propyl-4'-hydroxydiphenylsulfone,
4-isopropyl-4'-hydroxydiphenylsulfone,
4-chloro-4'-hydroxydiphenylsulfone,
4-fluoro-4'-hydroxydiphenylsulfone,
4-chloro-2-methyl-4'-hydroxydiphenylsulfone,
4-methoxy-4'-hydroxydiphenylsulfone,
4-ethoxy-4'-hydroxydiphenylsulfone,
4-n-propoxy-4'-hydroxydiphenylsulfone,
4-isopropoxy-4'-hydroxydiphenylsulfone,
4-n-butoxy-4'-hydroxydiphenylsulfone,
4-isobutoxy-4'-hydroxydiphenylsulfone,
4-sec-butoxy-4'-hydroxydiphenylsulfone,
4-tert-butoxy-4′-hydroxydiphenylsulfone,
4-n-pentyloxy-4'-hydroxydiphenylsulfone,
4-isopentyloxy-4'-hydroxydiphenylsulfone,
4-(1-propenyloxy)-4'-hydroxydiphenylsulfone,
4-(2-propenyloxy)-4'-hydroxydiphenylsulfone,
4-benzyloxy-4'-hydroxydiphenylsulfone,
4-(β-phenoxyethoxy)-4′-hydroxydiphenylsulfone,
4-(β-phenoxypropoxyl)-4′-hydroxydiphenylsulfone,
bis(2-allyl-4-hydroxydiphenyl)sulfone,
bis[4-hydroxy-3-(2-propenyl)phenyl]sulfone,
bis(3,5-dibromo-4-hydroxyphenyl)sulfone,
bis(3,5-dichloro-4-hydroxyphenyl)sulfone,
bis(3-phenyl-4-hydroxyphenyl)sulfone,
bis(4-hydroxy-3-n-propylphenyl)sulfone,
bis(4-hydroxy-3-methylphenyl)sulfone,
3,4-dihydroxydiphenyl sulfone,
3′,4′-dihydroxy-4-methyldiphenylsulfone,
3,4,4′-trihydroxydiphenyl sulfone,
bis(3,4-dihydroxyphenyl)sulfone,
2,3,4-trihydroxydiphenyl sulfone,
4-isopropoxy-4'-hydroxydiphenylsulfone,
4-n-propoxy-4'-hydroxydiphenylsulfone,
4-allyloxy-4'-hydroxydiphenylsulfone,
4-benzyloxy-4'-hydroxydiphenylsulfone,
4-(2-propenyloxy)-4'-hydroxydiphenylsulfone,
3-benzyl-4-benzyloxy-4'-hydroxydiphenylsulfone,
3-phenethyl-4-phenethyloxy-4'-hydroxydiphenylsulfone,
3-methylbenzyl-4-methylbenzyloxy-4'-hydroxydiphenylsulfone,
4-benzyloxy-3′-benzyl-4′-hydroxydiphenylsulfone,
4-phenethyloxy-3′-phenethyl-4′-hydroxydiphenylsulfone,
4-methylbenzyloxy-3'-methylbenzyl-4'-hydroxydiphenylsulfone,
α,α'-bis{4-(p-hydroxyphenylsulfone)phenoxy}-p-xylene,
4,4′-{oxybis(ethylene oxide-p-phenylenesulfonyl)}diphenol,
bis(4-hydroxyphenyl) sulfide, bis(4-hydroxy-3-methylphenyl) sulfide,
bis(3,5-dimethyl-4-hydroxyphenyl)sulfide,
bis(3-ethyl-4-hydroxyphenyl) sulfide,
bis(3,5-diethyl-4-hydroxyphenyl)sulfide,
bis(4-hydroxy-3-n-propylphenyl)sulfide,
bis(3,5-di-n-propyl-4-hydroxyphenyl)sulfide,
bis(3-tert-butyl-4-hydroxyphenyl)sulfide,
bis(3,5-di-tert-butyl-4-hydroxyphenyl)sulfide,
bis(4-hydroxy-3-n-pentylphenyl)sulfide,
bis(3-n-hexyl-4-hydroxyphenyl)sulfide,
bis(3-n-heptyl-4-hydroxyphenyl)sulfide,
bis(5-tert-octyl-2-hydroxyphenyl)sulfide,
bis(2-hydroxy-3-tert-octylphenyl)sulfide,
bis(2-hydroxy-5-n-octyl-phenyl)sulfide,
bis(5-chloro-2-hydroxyphenyl) sulfide,
bis(3-cyclohexyl-4-hydroxyphenyl)sulfide,
bis(4-hydroxyphenylthioethoxy)methane,
1,5-(4-hydroxyphenylthio)-3-oxypentane,
Examples include 1,8-bis(4-hydroxyphenylthio)-3,6-dioxaoctane.

Examples of compounds having three phenolic hydroxyl groups include pyrogallol, phloroglucinol, phloroglucinol carboxylic acid, gallic acid, octyl gallate, and dodecyl gallate.

Furthermore, as trisphenol compounds, for example,
4,4′,4″-methylidyne trisphenol,
4,4′,4″-methylidynetris(2-methylphenol),
4,4′-[(2-hydroxyphenyl)methylene]bis(2,3,5-trimethylphenol),
4,4′-[(4-hydroxyphenyl)methylene]bis(2-methylphenol),
4,4′-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol),
4,4′-[(4-hydroxy-3-methoxyphenyl)methylene]bisphenol,
4,4′-[(4-hydroxyphenyl)methylene]bis(2-cyclohexyl-5-methylphenol),
4,4′,4″-ethylidine trisphenol,
4,4′,4″-ethylidine tris(2-methylphenol),
4,4′-[(2-hydroxyphenyl)methylene]bis(2-cyclohexyl-5-methylphenol),
2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenol,
2,4-bis[(2-hydroxy-5-methylphenyl)methyl]-6-cyclohexylphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}methylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}propylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}butylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}pentylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}hexylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}heptylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}isobutylidene]bisphenol,
4,4′-[1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}neopentylidene]bisphenol,
2,2′-[1-{4-[1-(2-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bisphenol,
3,3′-[1-{4-[1-(3-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bisphenol,
4,4′-[1-{4-[1-(3-fluoro-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-fluorophenol),
4,4′-[1-{4-[1-(3-chloro-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-chlorophenol),
4,4′-[1-{4-[1-(3-bromo-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-bromophenol),
4,4′-[1-{4-[1-(4-hydroxy-3-methylphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-methylphenol),
4,4′-[1-{4-[1-(3-ethyl-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-ethylphenol),
4,4′-[1-{4-[1-(3-tert-butyl-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-tert-butylphenol),
4,4′-[1-{4-[1-(4-hydroxy-3-trifluoromethylphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-trifluoromethylphenol),
1,1-bis(4-hydroxyphenyl)-4-(4-hydroxy-α-ethyl)benzylcyclohexane,
4,4′-[(3-ethoxy-4-hydroxyphenyl)methylene]bisphenol,
4,4′-[(3-hydroxyphenyl)methylene]bis(2,6-dimethylphenol),
2,2′-[(4-hydroxyphenyl)methylene]bis(3,5-dimethylphenol),
4,4′-[(4-hydroxy-3-methoxyphenyl)methylene]bis(2,6-dimethylphenol),
2,2′-[(2-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol),
4,4′-[(3-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol),
4,4′-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol),
4,4′-[(3-hydroxyphenyl)methylene]bis(2-cyclohexyl-5-methylphenol),
4,4′-[(4-hydroxyphenyl-3-methoxy)methylene]bis(2-cyclohexyl-5-methylphenol),
1,1-bis(4-hydroxylphenyl)-4-hydroxyphenylcyclohexane,
4,4′-[3-(5-cyclohexyl-4-hydroxy-2-methylphenyl)-3-phenyl)propylidene]bis(2-cyclohexyl-5-methylphenol),
4,4′-[(2-hydroxyphenyl)methylene]bis(2-methylphenol),
2,4′,4″-methylidyne trisphenol,
4,4′-[(2-hydroxyphenyl)methylene]bis(3-methylphenol),
4,4′-[4-(4-hydroxyphenyl)-sec-butylidene]bis(4-hydroxyphenol),
2,2′-[(3-hydroxyphenyl)methylene]bis(3,5-dimethylphenol),
4,4′-[(2-hydroxy-3-methoxyphenyl)methylene]bis(2,5-dimethylphenol),
4,4′-[(2-hydroxy-3-methoxyphenyl)methylene]bis(2,6-dimethylphenol),
2,2′-[(2-hydroxy-3-methoxyphenyl)methylene]bis(3,5-dimethylphenol),
2,2′-[(3-hydroxy-4-methoxyphenyl)methylene]bis(3,5-dimethylphenol),
2,2′-[(4-hydroxy-3-methoxyphenyl)methylene]bis(3,5-dimethylphenol),
4,4′-[(2-hydroxyphenyl)methylene]bis(2-isopropylphenol),
4,4′-[(3-hydroxyphenyl)methylene]bis(2-isopropylphenol),
4,4′-[(4-hydroxyphenyl)methylene]bis(2-isopropylphenol),
2,2′-[(3-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol),
2,2′-[(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol),
2,2′-[(3-ethoxy-4-hydroxyphenyl)methylene]bis(3,5-dimethylphenol),
1,1-bis(4-hydroxy-3-methylphenyl)-4-(4-hydroxyphenyl)cyclohexane,
4,4′-[(2-hydroxy-3-methoxyphenyl)methylene]bis(2-isopropylphenol),
4,4′-[(3-hydroxy-4-methoxyphenyl)methylene]bis(2-isopropylphenol),
4,4′-[(4-hydroxy-3-methoxyphenyl)methylene]bis(2-isopropylphenol),
2,2′-[(2-hydroxy-3-methoxyphenyl)methylene]bis(3,5,6-trimethylphenol,
2,2′-[(3-hydroxy-4-methoxyphenyl)methylene]bis(3,5,6-trimethylphenol),
2,2′-[(4-hydroxy-3-methoxyphenyl)methylene]bis(3,5,6-trimethylphenol),
4,4′-[(3-ethoxy-4-hydroxyphenyl)methylene]bis(2-isopropylphenol),
2,2′-[(3-ethoxy-4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol),
4,4′-[(3-ethoxy-4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol),
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)cyclohexane,
4,4′-[(4-hydroxy-3-methoxyphenyl)methylene]bis(2-tert-butyl-5-methylphenol),
4,4′-[(2-hydroxyphenyl)methylene]bis(2-cyclohexylphenol),
4,4′-[(3-hydroxyphenyl)methylene]bis(2-cyclohexylphenol),
4,4′-[(3-ethoxy-4-hydroxyphenyl)methylene]bis(2-tert-butyl-6-methylphenol),
4,4′-[(3-methoxy-2-hydroxyphenyl)methylene]bis(2-cyclohexylphenol),
4,4′-[(3-hydroxy-4-methoxyphenyl)methylene]bis(2-cyclohexylphenol),
4,4′-[1-{4-[1-(3-fluoro-4-hydroxylophenyl)-1-methylethyl]phenyl}ethylidene]bis(2-tert-butylphenol),
4,4′-[1-{4-[1-(3,5-dimethyl-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2,6-dimethylphenol),
4,4′-[(3-ethoxy-4-hydroxyphenyl)methylene]bis(2-cyclohexyl-5-methylphenol),
4,4′-[(3-cyclohexyl-4-hydroxyphenyl)ethylidene]bis(2-cyclohexylphenol),
4,4′-[(5-cyclohexyl-4-hydroxy-2-methoxyphenyl)ethylidene]bis(2-cyclohexyl-5-methylphenol),
4,4′-[1-{4-[1-(3-cyclohexyl-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-cyclohexylphenol),
4,4′-[1-{4-[1-(3-fluoro-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bisphenol,
4,4′-[1-{4-[1-(3-fluoro-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2-methylphenol),
4,4′-[1-{4-[1-(3-fluoro-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis(2,6-dimethylphenol),
2,6-bis[(5-fluoro-2-hydroxyphenyl)methyl]-4-methylphenol,
2,6-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]-4-methylphenol,
2,6-bis[(4-hydroxyphenyl)methyl]-4-methylphenol,
2,6-bis[(4-hydroxyphenyl)methyl]-4-ethylphenol,
2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-methylphenol,
2,6-bis[(4-hydroxy-3-methylphenyl)methyl]-4-methylphenol,
2,6-bis[(4-hydroxy-3-methylphenyl)methyl]-4-ethylphenol,
2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-ethylphenol,
2,6-bis[(3,5-dimethyl-2-hydroxyphenyl)methyl]-4-methylphenol,
2,6-bis[(2,4-dimethyl-6-hydroxyphenyl)methyl]-4-methylphenol,
2,4-bis[(4-hydroxyphenyl)methyl]-6-cyclohexylphenol,
2,6-bis[(2,5-dimethyl-4-hydroxyphenyl)methyl]-3,4-dimethylphenol,
2,6-bis[(2,5-dimethyl-4-hydroxyphenyl)methyl]-4-ethylphenol,
2,6-bis[(4-hydroxy-2,3,6-trimethylphenyl)methyl]-4-methylphenol,
2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-cyclohexylphenol,
2,6-bis[(4-hydroxy-3-methylphenyl)methyl]-4-cyclohexylphenol,
2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-cyclohexylphenol,
2,6-bis[(4-hydroxy-2,3,5-trimethylphenyl)methyl]-4-ethylphenol,
2,4-bis[(2,5-dimethyl-4-hydroxyphenyl)methyl]-6-cyclohexylphenol,
4,4′,4″-methylidinetris(2,6-dimethylphenol),
α-(4-hydroxy-3-methylphenyl)-α,α'-bis(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene,
α′-(4-hydroxy-3-methylphenyl)-α,α-bis(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene,
α,α-bis(4-hydroxy-3-methylphenyl)-α'-(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene,
α,α'-bis(4-hydroxy-3-methylphenyl)-α-(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene,
1,1-bis(4-hydroxyphenyl)-4-[1-(4-hydroxyphenyl)-1-methylpropyl]cyclohexane,
2,6-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]-4-ethylphenol,
1,1′-bis(4-hydroxyphenyl)-4-[1-(4-hydroxyphenyl)propyl]cyclohexane,
1,1′-bis(4-hydroxy-3-methylphenyl)-4-[1-(4-hydroxyphenyl)propyl]cyclohexane,
1,1′-bis(3,5-dimethyl-4-hydroxyphenyl)-4-[1-(4-hydroxyphenyl)propyl]cyclohexane,
1-(4-hydroxyphenyl)-1-[4,4-bis(4-hydroxyphenyl)cyclohexyl]-4-isopropylcyclohexane,
4,4′-[3-(2,5-dimethyl-4-hydroxyphenyl)butylene]bis(2,5-dimethylphenol),
1,3,5-tri(4-hydroxy-3-phenylphenyl)adamantane,
1,3,5-tri(3-cyclohexyl-4-hydroxyphenyl)adamantane,
2,4-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]-6-cyclohexylphenol,
2,6-bis[(2,5-dimethyl-4-hydroxyphenyl)methyl]-4-cyclohexylphenol,
2,4-bis[(3-cyclohexyl-4-hydroxyphenyl)methyl]-6-methylphenol,
2,4-bis[(4-hydroxy-2,3,5-trimethylphenyl)methyl]-6-cyclohexylphenol,
2,6-bis[(5-fluoro-2-hydroxyphenyl)methyl]-4-fluorophenol,
2,6-bis[(3-fluoro-4-hydroxyphenyl)methyl]-4-fluorophenol,
2,4-bis[(3-fluoro-4-hydroxyphenyl)methyl]-6-methylphenol,
4,4′-[3-(5-cyclohexyl-4-hydroxy-2-methylphenyl)-3-biphenylpropylidene]bis(5-cyclohexyl-2-methylphenol),
4,4′-[3-(2,5-dimethyl-4-hydroxyphenyl)-3-phenylpropylidene]bis(2,5-dimethylphenol),
2,4-bis[(2,5-dimethyl-4-hydroxyphenyl)methyl]-6-methylphenol,
1,1,2-tris(4-hydroxyphenyl)ethane,
1,1,3-tris(4-hydroxyphenyl)propane,
1,1,4-tris(4-hydroxyphenyl)butane,
1,2,2-tris(4-hydroxyphenyl)propane,
1,2,2-tris(4-hydroxyphenyl)butane,
1,2,2-tris(4-hydroxyphenyl)pentane,
1,2,2-tris(4-hydroxyphenyl)hexane,
1,2,2-tris(4-hydroxyphenyl)heptane,
1,2,2-tris(4-hydroxyphenyl)octane,
1,2,2-tris(4-hydroxyphenyl)-3-methylbutane 1,2,2-tris(4-hydroxyphenyl)-3,3-dimethylbutane,
1,2,2-tris(4-hydroxyphenyl)-4,4-dimethylpentane,
1,3,3-tris(4-hydroxyphenyl)butane,
1,3,3-tris(4-hydroxyphenyl)pentane,
1,3,3-tris(4-hydroxyphenyl)hexane,
1,3,3-tris(4-hydroxyphenyl)heptane,
1,3,3-tris(4-hydroxyphenyl)octane,
1,3,3-tris(4-hydroxyphenyl)nonane,
1,4,4-tris(4-hydroxyphenyl)pentane,
1,4,4-tris(4-hydroxyphenyl)hexane,
1,4,4-tris(4-hydroxyphenyl)heptane,
1,4,4-tris(4-hydroxyphenyl)octane,
1,4,4-tris(4-hydroxyphenyl)nonane,
1,4,4-tris(4-hydroxyphenyl)decane,
1,2,2-tris(2-hydroxyphenyl)propane,
1,1,2-tris(3-hydroxyphenyl)propane,
1-(4-hydroxyphenyl)-2,2-bis(2-hydroxyphenyl)propane,
1,2,2-tris(3-fluoro-4-hydroxyphenyl)propane,
1,2,2-tris(3-chloro-4-hydroxyphenyl)propane,
1,2,2-tris(3-bromo-4-hydroxyphenyl)propane,
2,2-bis(3-ethyl-4-hydroxyphenyl)-1-(4-hydroxyphenyl)propane,
2,2-bis(3-tert-butyl-4-hydroxyphenyl)-1-(4-hydroxyphenyl)propane,
2,2-bis(2-hydroxy-3-biphenylyl)-1-(4-hydroxyphenyl)propane,
2,2-bis(3-trifluoromethyl-4-hydroxyphenyl)-1-(4-hydroxyphenyl)propane,
2-(3-methyl-4-hydroxyphenyl)-1,2-bis(4-hydroxyphenyl)propane,
1-(3-methyl-4-hydroxyphenyl)-2,2-bis(4-hydroxyphenyl)propane,
3-(3-methyl-4-hydroxyphenyl)-1,3-bis(4-hydroxyphenyl)butane,
1-(3-methyl-4-hydroxyphenyl)-3,3-bis(4-hydroxyphenyl)butane,
4-(3-methyl-4-hydroxyphenyl)-1,4-bis(4-hydroxyphenyl)pentane,
1-(3-methyl-4-hydroxyphenyl)-4,4-bis(4-hydroxyphenyl)pentane,
1,2-bis(3-methyl-4-hydroxyphenyl)-2-(4-hydroxyphenyl)propane,
3,3-bis(3-methyl-4-hydroxyphenyl)-1-(4-hydroxyphenyl)butane,
1,3-bis(3-methyl-4-hydroxyphenyl)-3-(4-hydroxyphenyl)butane,
4,4-bis(3-methyl-4-hydroxyphenyl)-1-(4-hydroxyphenyl)pentane,
1,4-bis(3-methyl-4-hydroxyphenyl)-4-(4-hydroxyphenyl)pentane,
1,1,2-tris(3-methyl-4-hydroxyphenyl)ethane,
1,2,2-tris(3-methyl-4-hydroxyphenyl)propane,
1,1,3-tris(3-methyl-4-hydroxyphenyl)propane,
1,3,3-tris(3-methyl-4-hydroxyphenyl)butane,
1,1,4-tris(3-methyl-4-hydroxyphenyl)butane,
1,4,4-tris(3-methyl-4-hydroxyphenyl)pentane,
4,4′-[4-(4-hydroxyphenyl)-sec-butylidene]bis(2-methylphenol)
etc. can be exemplified.

Examples of compounds having four or more phenolic hydroxyl groups include
bis[2-hydroxy-3-(2-hydroxy-5-methylbenzyl)-5-methylphenyl]methane,
4,6-bis[(4-hydroxyphenyl)methyl)-1,3-benzenediol,
4,4′-[(3,4-dihydroxyphenyl)methylene]bis(2,6-dimethylphenol),
4,4′-[(3,4-dihydroxyphenyl)methylene]bis(2-cyclohexyl-5-methylphenol),
4,4′-[(3,4-dihydroxyphenyl)methylene]bis(2-methylphenol),
4,4′-[(3,4-dihydroxyphenyl)methylene]bis(2,3,6-trimethylphenol),
1,1,2,2-tetrakis(4-hydroxyphenyl)ethane,
4,4′,4″,4′″-(1,1,2,2-ethanetetrayl)tetrakis(2-methylphenol),
4,4′,4″,4′″-(1,1,2,2-ethanetetrayl)tetrakis(2,6-dimethylphenol),
4,4′,4″,4′″-(1,4-phenylene)bis(methylidine)tetrakis(2,6-dimethylphenol),
2,2-bis[4,4-bis(4-hydroxy-3-methylphenyl)cyclohexyl]propane,
2,2′-[(3,4-dihydroxyphenyl)methylene]bis(3,5-dimethylphenol),
4,6-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]-1,3-benzenediol,
2,2′-[(3,4-dihydroxyphenyl)methylene]bis(3,5,6-trimethylphenol),
4,4′-[(3,4-dihydroxyphenyl)methylene]bis(2-cyclohexylphenol),
bis[4-hydroxy-3-(2-hydroxybenzyl)-5-methylphenyl]methane,
bis[4-hydroxy-3-(3-hydroxybenzyl)-5-methylphenyl]methane,
bis[4-hydroxy-3-(4-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(2-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(3-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(4-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(3-hydroxy-4-methylbenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(4-hydroxy-3-methylbenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(3-hydroxy-2-methylbenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(2-hydroxy-3-methylbenzyl)-5-methylphenyl]methane,
α,α′,α″,α′″-tetrakis(4-hydroxyphenyl)-p-xylene,
bis[2-hydroxy-3-(4-hydroxy-2,3,5-trimethylbenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(2,5-dimethyl-3-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(2,5-dimethyl-4-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(2,5-dimethyl-5-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(3,5-dimethyl-4-hydroxybenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(2-hydroxy-3,4,6-trimethylbenzyl)-5-methylphenyl]methane,
bis[2-hydroxy-3-(4-hydroxy-2,3,6-trimethylbenzyl)-5-methylphenyl]methane,
4,4,4′,4′-tetrakis(4-hydroxyphenyl)bicyclohexyl,
bis[4-hydroxy-3-(5-cyclohexyl-4-hydroxy-2-methylbenzyl)-5-methylphenyl]methane,
4,4,4′,4′-tetrakis(4-hydroxy-3-methylphenyl)bicyclohexyl,
4,6-bis(3,5-dimethyl-4-hydroxyphenyl)-1,2-benzenediol,
4,4,4′,4′-tetrakis(3,5-dimethyl-4-hydroxyphenyl)bicyclohexyl,
1,1-bis[5-cyclohexyl-4-hydroxy-3-(2-hydroxy-5-methylbenzyl)phenyl]cyclohexane,
1,1-bis[5-cyclohexyl-4-hydroxy-3-(3,5-dimethyl-4-hydroxybenzyl)phenyl]cyclohexane,
1,1-bis[5-cyclohexyl-4-hydroxy-3-(5-cyclohexyl-4-hydroxy-2-methylbenzyl)phenyl]cyclohexane,
4,6-bis[1-(4-hydroxyphenyl)ethyl]-1,3-benzenediol,
2,2-bis[4-hydroxy-3-(4-hydroxy-3-methylbenzyl)-5-methylphenyl]propane,
2,6-bis[(3,5-dimethyl-4-hydroxyphenyl)benzyl]-4-[α-methyl-(3,5-dimethyl-4-hydroxyphenyl)benzyl]phenol,
4,4,4′,4′-tetrakis(3-isopropyl-4-hydroxyphenyl)bicyclohexyl,
4,4′-bis[(3,4-dihydroxyphenyl)methylene]bis(2-isopropylphenol),
2,2′-bis[4,4-bis(4-hydroxyphenyl)cyclohexyl]propane,
2,4,6-tris(4-hydroxybenzyl)-1,3-benzenediol,
4,6-bis(3,5-dimethyl-4-hydroxybenzyl)-1,2,3-benzenetriol,
3,3′-[(2-hydroxyphenyl)methylene]bis(5-methyl-1,2-benzenediol),
2,6-bis(2,4-dihydroxybenzyl)-4-ethylphenol,
2,4-bis(2,4-dihydroxybenzyl)-6-cyclohexylphenol,
2,6-bis(5-tert-butyl-2,3-dihydroxybenzyl)-4-methylphenol,
2,4,6-tris(3,5-dimethyl-4-hydroxybenzyl)-1,2-benzenediol,
2,4,6-tris(3,5-dimethyl-2-hydroxybenzyl)-1,2-benzenediol,
2,6-bis(2,4-dihydroxybenzyl)-3,4-dimethylphenol,
2,6-bis[3-(2-hydroxy-5-methylbenzyl)-2,5-dimethyl-4-hydroxybenzyl]-3,4-dimethylphenol,
4,6-bis(α-methyl-4-hydroxybenzyl)-1,2,3-benzenetriol,
4,4′-[1-{4-[1-(3,5-bis(4-hydroxybenzyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[2,6-bis( 4-hydroxybenzyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(4-hydroxy-3-methylbenzyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[2, 6-bis(4-hydroxy-3-methylbenzyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(3,5-dimethyl-4-hydroxybenzyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[ 2,6-bis(3,5-dimethyl-4-hydroxybenzyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(4-hydroxy-2,3,6-trimethylbenzyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene] bis[2,6-bis(4-hydroxy-2,3,6-trimethylbenzyl)phenol],
bis[5-(2,4-dihydroxybenzyl)-4-hydroxy-3-methylphenyl]methane,
bis[3-(2,4-dihydroxybenzyl)-2,5-dimethyl-4-hydroxyphenyl]methane,
bis[3-(2,4-dihydroxy-3-methylbenzyl)-2,5-dimethyl-4-hydroxyphenyl]methane,
bis[5-(4-hydroxybenzyl)-2,3,4-trihydroxyphenyl]methane,
1,1-bis[5-(4-hydroxybenzoyl)-2,3,4-trihydroxyphenyl]ethane,
3,3′,5,5′-tetrakis(4-hydroxybenzyl)-4,4′-dihydroxybiphenyl,
3,3′,5,5′-tetrakis(4-hydroxy-3-methylbenzyl)-4,4′-dihydroxybiphenyl,
3,3′,5,5′-tetrakis(2-hydroxy-5-methylbenzyl)-4,4′-dihydroxybiphenyl,
3,3′,5,5′-tetrakis(3,5-dimethyl-4-hydroxybenzyl)-4,4′-dihydroxybiphenyl,
bis[3-(α,α-bis(4-hydroxy-3-methylphenyl)methyl-4-hydroxyphenyl]methane,
bis[3,5-bis(2-hydroxy-5-methylbenzyl)-4-hydroxyphenyl]methane,
4,4′,4″-ethylidinetris{[2-(2-hydroxy-5-methyl)benzyl]-6-methylphenol},
2,2-bis[3,5-bis(2-hydroxy-5-methylphenylmethyl)phenyl]propane,
bis[3-(α,α-bis(2,5-dimethyl-4-hydroxyphenyl)methyl-4-hydroxyphenyl]methane,
bis[5-(3,5-dimethyl-4-hydroxybenzyl)-2,3,4-trihydroxyphenyl]methane,
bis[3-(2,3,4-trihydroxybenzyl)-2,5-dimethyl-4-hydroxyphenyl]methane,
1,1-bis[3-(2,3,4-trihydroxybenzyl)-5-cyclohexyl-4-hydroxyphenyl]cyclohexane,
1,8,15,22-tetranonyl-3,5,10,12,17,19,24,26-octahydroxy[1,1,1,1]-metacyclophane,
4,4′-[1-{4-[1-(3,5-bis(4-hydroxy-2-methylbenzyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[2, 6-bis(4-hydroxy-2-methylbenzyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(2-hydroxy-5-methylbenzyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[2, 6-bis(2-hydroxy-5-methylbenzyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(3-ethyl-4-hydroxybenzyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[2, 6-bis(3-ethyl-4-hydroxybenzyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(3,5-dimethyl-2-hydroxyphenyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[ 2,6-bis(3,5-dimethyl-2-hydroxyphenyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(4-hydroxy-3-isopropylphenyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[2, 6-bis(4-hydroxy-3-isopropylphenyl)phenol],
bis[3-(α,α-bis(3,5-dimethyl-4-hydroxyphenyl)methyl-4-hydroxyphenyl]methane,
bis[3-(α,α-bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)methyl-4-hydroxyphenyl]methane,
4,4′-[4-hydroxy-3,5-bis(2-hydroxybenzyl)methylene]bis[2,6-bis(2-hydroxybenzyl)]phenol,
4,4′-[4-hydroxy-3,5-bis(4-hydroxybenzyl)methylene]bis[2,6-bis(4-hydroxybenzyl)]phenol,
4,4′,4″-ethylidinetris[2,6-bis(2-hydroxybenzyl)phenol],
4,4′,4″-ethylidinetris[2,6-bis(4-hydroxybenzyl)phenol],
2,2-bis[3,5-bis(4-hydroxy-3-methylbenzyl)-4-hydroxyphenyl]propane,
1,8,15,22-tetraethyl-3,5,10,12,17,19,24,26-octahydroxy[1,1,1,1]-metacyclophane,
α,α′,α″,α′″-tetrakis(3,5-dimethyl-4-hydroxyphenyl)-1,4-dimethylbenzene,
4,4′-[1-{4-[1-(3,5-bis(2-hydroxy-5-isopropylphenyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[2, 6-bis(2-hydroxy-5-isopropylphenyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(4-hydroxy-2,3,5-trimethylphenyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene] bis[2,6-bis(4-hydroxy-2,3,5-trimethylphenyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(3-sec-butyl-4-hydroxyphenyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[ 2,6-bis(3-sec-butyl-4-hydroxyphenyl)phenol],
4,4′-[1-{4-[1-(3,5-bis(3-tert-butyl-4-hydroxyphenyl)-4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene]bis[ 2,6-bis(3-tert-butyl-4-hydroxyphenyl)phenol],
2,6-bis{[3-(2,4-dihydroxybenzyl)-2,5-dimethyl-4-hydroxy]benzyl}-4-methylphenol,
1,1-bis[5-(2,4-dihydroxybenzyl)-3-cyclohexyl-4-hydroxyphenyl]cyclohexane,
1,1-bis[5-(2,3,4-trihydroxybenzyl)-3-cyclohexyl-4-hydroxyphenyl]cyclohexane,
2,2-bis[4,4',4″,4′″-tetrakis(3,5-dihydroxymethyl-4-hydroxyphenyl)cyclohexyl]propane and the like can be exemplified.

Carboxylic acids and derivatives thereof include, for example,
3,5-di(α-methylbenzyl)salicylic acid,
4-(2-p-methoxyphenyloxyethoxy)salicylic acid,
4-hydroxyphenylbenzoic acid,
4-chlorobenzoic acid,
4-[2-(p-methoxyphenoxy)ethyloxy]salicylic acid,
4-[3-(p-tolylsulfonyl)propyloxy]salicylic acid,
5-[p-(2-p-methoxyphenoxyethoxy)cumyl]salicylic acid,
4-octyloxycarbonylaminosalicylic acid,
3,5-distyrenated salicylic acid,
N-(p-toluenesulfonyl)-glycine,
N-(p-toluenesulfonyl)-alanine,
N-(p-toluenesulfonyl)-β-alanine,
N-phenylaminocarbonyl-glycine,
N-phenylaminocarbonyl-valine,
N-(m-tolylaminocarbonyl)-phenylalanine,
N-(m-tolylaminocarbonyl)-cysteine-S-benzyl,
N-(m-tolylaminocarbonyl)-methionine,
N-(m-tolylaminocarbonyl)-tyrosine,
N-(p-tolylaminocarbonyl)-phenylalanine,
N-(p-tolylaminocarbonyl)-cysteine-S-benzyl,
N-(p-tolylaminocarbonyl)-methionine,
N-(phenylaminocarbonyl)-methionine,
N-(p-tolylaminocarbonyl)-tyrosine,
2-O-(phenylaminocarbonyl)-mandelic acid,
2-O-(p-tolylaminocarbonyl)-mandelic acid,
2-O-(m-tolylaminocarbonyl)-mandelic acid,
2-O-(o-tolylaminocarbonyl)-mandelic acid,
2-O-(1-naphthylaminocarbonyl)-mandelic acid,
2-O-(3-isopropenyl-α,α-dimethylbenzylaminocarbonyl)-mandelic acid,
2-O-(benzylaminocarbonyl)-mandelic acid,
2-O-(phenethylaminocarbonyl)-mandelic acid,
2-O-(phenylaminocarbonyl)-lactic acid,
2-O-(p-tolylaminocarbonyl)-lactic acid,
2-O-(m-tolylaminocarbonyl)-lactic acid,
2-O-(o-tolylaminocarbonyl)-lactic acid,
2-O-(1-naphthylaminocarbonyl)-lactic acid,
2-O-(3-isopropenyl-α,α-dimethylbenzylaminocarbonyl)-lactic acid,
2-O-(benzylaminocarbonyl)-lactic acid,
Examples include 2-O-(phenethylaminocarbonyl)-lactic acid and the like.

Acidic phosphoric ester compounds include, for example, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, isodecyl acid phosphate, isotridecyl acid phosphate, oleyl acid phosphate, tetracosylate. Examples include luacid phosphate, monobutyl phosphate, dibutyl phosphate, monoisodecyl phosphate, bis(2-ethylhexyl) phosphate and the like.

As the component (b), a compound having a phenolic hydroxyl group is preferable because it can more effectively express the heat discoloration property. , acidic phosphates and metal salts thereof, and 1,2,3-triazoles and derivatives thereof.

The (c) component of the reaction medium that reversibly causes the electron transfer reaction by the (a) component and the (b) component in a specific temperature range will be described.
Component (c) includes alcohols, esters, ketones, ethers, and acid amides.

When the reversible thermochromic composition is encased in microcapsules and applied to secondary processing, low molecular weight substances evaporate out of the capsules when subjected to high heat treatment. Compounds of several tens or more are preferably used.

As alcohols, aliphatic monohydric saturated alcohols having 10 or more carbon atoms are effective. Examples include heptadecyl alcohol, octadecyl alcohol, eicosyl alcohol, and docosyl alcohol.

As esters, esters having 10 or more carbon atoms are effective, and arbitrary combinations of monovalent carboxylic acids having aliphatic and alicyclic or aromatic rings and monohydric alcohols having aliphatic and alicyclic or aromatic rings are used. Esters obtained from any combination of polycarboxylic acids having aliphatic and alicyclic or aromatic rings and monohydric alcohols having aliphatic and alicyclic or aromatic rings, aliphatic and alicyclic Alternatively, esters obtained from any combination of a monovalent carboxylic acid having an aromatic ring and a polyhydric alcohol having an aliphatic, alicyclic or aromatic ring, such as ethyl caprylate, octyl caprylate, and 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, stearic acid n -butyl, 2-methylbutyl stearate, 3,5,5-trimethylhexyl stearate, n-undecyl stearate, pentadecyl stearate, stearyl stearate, cyclohexylmethyl stearate, isopropyl behenate, hexyl behenate, lauryl behenate , behenyl behenate, cetyl benzoate, 4-tert-butyl stearyl 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 trimyristate, 1,4-cyclohexanediol didecyl, 1,4-cyclohexanedimethanol dimyristate, xylene glycol dicaprinate, xylene glycol distearate A rate etc. can be illustrated.

Esters of saturated fatty acids and branched fatty alcohols, and ester compounds of unsaturated fatty acids or branched or substituted saturated fatty acids with branched or C 16 or more fatty alcohols are also effective. be.

Examples of ester compounds include 2-ethylhexyl butyrate, 2-ethylhexyl behenate, 2-ethylhexyl myristate, 2-ethylhexyl caprate, 3,5,5-trimethylhexyl laurate, and 3,5,5-trimethyl palmitate. Hexyl, 3,5,5-trimethylhexyl stearate, 2-methylbutyl caproate, 2-methylbutyl caprylate, 2-methylbutyl caprate, 1-ethylpropyl palmitate, 1-ethylpropyl stearate, 1-ethyl behenate Propyl, 1-ethylhexyl laurate, 1-ethylhexyl myristate, 1-ethylhexyl palmitate, 2-methylpentyl caproate, 2-methylpentyl caprylate, 2-methylpentyl caprate, 2-methylpentyl laurate, stearic acid 2-methylbutyl, 2-methylbutyl stearate, 3-methylbutyl stearate, 1-methylheptyl stearate, 2-methylbutyl behenate, 3-methylbutyl behenate, 1-methylheptyl stearate, 1-methylheptyl behenate, capron 1-ethylpentyl acid, 1-ethylpentyl palmitate, 1-methylpropyl stearate, 1-methyloctyl stearate, 1-methylhexyl stearate, 1,1-dimethylpropyl laurate, 1-methylpentyl caprate, 2-methylhexyl palmitate, 2-methylhexyl stearate, 2-methylhexyl behenate, 3,7-dimethyloctyl laurate, 3,7-dimethyloctyl myristate, 3,7-dimethyloctyl palmitate, stearic acid 3,7-dimethyloctyl, 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, isostearyl 2-ketomyristate, 2-ethylhexyl 2-fluoromyristate, cetyl butyrate, stearyl butyrate, Behenyl butyrate and the like can be exemplified.

Furthermore, in order to discolor with a large hysteresis characteristic with respect to the color density-temperature curve and to provide color memory depending on temperature change, a temperature of 5 ° C. or more and less than 50 ° C. described in JP-B-4-17154 is used. Carboxylic acid ester compounds exhibiting a ΔT value (melting point - clouding point), for example, a carboxylic acid ester containing a substituted aromatic ring in the molecule, a carboxylic acid containing an unsubstituted aromatic ring, and an aliphatic alcohol having 10 or more carbon atoms Esters, carboxylic acid esters containing a cyclohexyl group in the molecule, esters of fatty acids with 6 or more carbon atoms and unsubstituted aromatic alcohols or phenols, esters of fatty acids with 8 or more carbon atoms and branched aliphatic alcohols, dicarboxylic acids and aromatics dibenzyl cinnamate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, dicetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearin, di Examples include myristin, distearin, and the like.

Further, a fatty acid ester compound obtained from an odd aliphatic monohydric alcohol having 9 or more carbon atoms and an even aliphatic carboxylic acid having an even number of carbon atoms, n-pentyl alcohol or n-heptyl alcohol, and an even number having 10 to 16 carbon atoms A fatty acid ester compound having a total carbon number of 17-23 obtained from an aliphatic carboxylic acid is also effective.

Examples of fatty acid ester compounds include n-pentadecyl acetate, n-tridecyl butyrate, n-pentadecyl butyrate, n-undecyl caproate, n-tridecyl caproate, n-pentadecyl caproate, n-nonyl caprylate, and n caprylate. -undecyl, n-tridecyl caprylate, n-pentadecyl caprylate, n-heptyl caprate, n-nonyl caprate, n-undecyl caprate, n-tridecyl caprate, n-pentadecyl caprate, n-pentyl laurate , n-heptyl laurate, n-nonyl laurate, n-undecyl laurate, n-tridecyl laurate, n-pentadecyl laurate, n-pentyl myristate, n-heptyl myristate, n-nonyl myristate, myristic n-undecyl acid, n-tridecyl myristate, n-pentadecyl myristate, n-pentyl palmitate, n-heptyl palmitate, n-nonyl palmitate, n-undecyl palmitate, n-tridecyl palmitate, n-palmitate -Pentadecyl, n-nonyl stearate, n-undecyl stearate, n-tridecyl stearate, n-pentadecyl stearate, n-nonyl eicosanoate, n-undelsi eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate , n-nonyl behenate, n-undecyl behenate, n-tridecyl behenate, n-pentadecyl behenate and the like.

Effective ketones are aliphatic ketones having a total carbon number of 10 or more, such as 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, and 5-undecanone. , 2-dodecanone, 3-dodecanone, 4-dodecanone, 5-dodecanone, 2-tridecanone, 3-tridecanone, 2-tetradecanone, 2-pentadecanone, 8-pentadecanone, 2-hexadecanone, 3-hexadecanone, 9-heptadecanone, 2 -pentadecanone, 2-octadecanone, 2-nonadecanone, 10-nonadecanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, laurone, stearone and the like.

Furthermore, arylalkyl ketones having a total carbon number of 12 to 24, such as n-octadecanophenone, n-heptadecanophenone, n-hexadecanophenone, n-pentadecanophenone, n-tetradecanophenone. nophenone, 4-n-dodecaacetophenone, n-tridecanophenone, 4-n-undecanoacetophenone, n-laurophenone, 4-n-decanoacetophenone, n-undecanophenone, 4-n-nonylacetophenone, n-decanophenone, 4-n-octylacetophenone, n-nonanophenone, 4-n-heptylacetophenone, n-octanophenone, 4-n-hexylacetophenone, 4-n-cyclohexylacetophenone, 4-tert-butylpropiophenone , n-heptaphenone, 4-n-pentylacetophenone, cyclohexylphenyl ketone, benzyl-n-butyl ketone, 4-n-butylacetophenone, n-hexanophenone, 4-isobutylacetophenone, 1-acetonaphtone, 2-acenaphthone, cyclopentylphenyl A ketone etc. can be illustrated.

Aliphatic ethers having a total carbon number of 10 or more are effective as ethers. , 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. can be exemplified.

Acid amides include, for example, acetamide, propionamide, butyric acid amide, caproic acid amide, caprylic acid amide, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, olein Acid amide, erucamide, benzamide, caproic acid anilide, caprylic acid anilide, capric acid anilide, lauric acid anilide, myristate anilide, palmitic acid anilide, stearic acid anilide, behenic acid anilide, oleic acid anilide, erucic acid anilide, capron acid N-methylamide, caprylic acid N-methylamide, capric acid N-methylamide, lauric acid N-methylamide, myristate 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, myristate N-ethylamide, palmitic acid N-ethylamide, stearic acid N-ethylamide, oleic acid N-ethylamide, lauric acid N-butylamide, myristate N-butylamide , N-butylamide palmitate, N-butylamide stearate, N-butylamide oleate, N-octylamide laurate, N-octylamide myristate, N-octylamide palmitate, N-octylamide stearate, N-oleic acid - octylamide, lauric acid N-dodecylamide, myristate N-dodecylamide, palmitic acid N-dodecylamide, stearic acid N-dodecylamide, oleic acid N-dodecylamide, dilauric acid amide, dimyristate amide, dipalmitin Acid amide, distearic amide, dioleic amide, trilauric amide, trimyristic amide, tripalmitic amide, tristearic amide, trioleic amide, succinic amide, adipic amide, glutaric amide, malonic amide , azelaic acid amide, maleic acid amide, succinic acid N-methylamide, adipic acid N-methylamide, glutaric acid N-methylamide, malonic acid N-methylamide, azelaic acid N-methylamide, succinic acid N-ethylamide, adipic acid N-ethylamide , glutaric acid N-ethylamide, malonic acid N-ethylamide, azelaic acid N-ethylamide, succinic acid N-butylamide, adipate Examples include acid N-butylamide, glutaric acid N-butylamide, malonic acid N-butylamide, adipic acid N-octylamide, adipic acid N-dodecylamide and the like.

〔式中、Ｒ_１は水素原子またはメチル基を示し、ｍは０～２の整数を示し、Ｘ_１およびＸ_２のいずれか一方は－（ＣＨ_２）_ｎＯＣＯＲ_２または（ＣＨ_２）_ｎＣＯＯＲ_２、他方は水素原子を示し、ｎは０～２の整数を示し、Ｒ_２は炭素数４以上のアルキル基またはアルケニル基を示し、Ｙ_１およびＹ_２はそれぞれ独立して、水素原子、炭素数１～４のアルキル基、メトキシ基、ハロゲン原子のいずれかを示し、ｒおよびｐはそれぞれ独立して、１～３の整数を示す。〕 Moreover, the compound represented by the following formula (1) may be used as the component (c).

[In the formula, R ₁ represents a hydrogen atom or a methyl group, m represents an integer of 0 to 2, and one of X ₁ and X ₂ is -(CH ₂ ) _n OCOR ₂ or (CH ₂ ) _n COOR ₂ , the other represents a hydrogen atom, n represents an integer of 0 to 2, R ₂ represents an alkyl group or alkenyl group having 4 or more carbon atoms, Y ₁ and Y ₂ each independently represent a hydrogen atom, a carbon represents an alkyl group, a methoxy group or a halogen atom of numbers 1 to 4; r and p each independently represents an integer of 1 to 3; ]

Among the compounds represented by formula (3), when R ₁ is a hydrogen atom, it is preferable because a reversible thermochromic composition having a wider hysteresis width can be obtained, and further R ₁ is a hydrogen atom and m is 0 is more preferred.

（式中、Ｒは炭素数８以上のアルキル基またはアルケニル基を示し、好ましくは炭素数１０～２４のアルキル基であり、より好ましくは炭素数１２～２２のアルキル基である。） Among the compounds represented by the formula (1), the compounds represented by the following formula (2) are more preferable.

(In the formula, R represents an alkyl group or alkenyl group having 8 or more carbon atoms, preferably an alkyl group having 10 to 24 carbon atoms, more preferably an alkyl group having 12 to 22 carbon atoms.)

Examples of compounds represented by formula (2) include 4-benzyloxyphenylethyl octanoate, 4-benzyloxyphenylethyl nonanoate, 4-benzyloxyphenylethyl decanoate, 4-benzyloxyphenylethyl undecanoate, and dodecane. 4-benzyloxyphenylethyl acid, 4-benzyloxyphenylethyl tridecanoate, 4-benzyloxyphenylethyl tetradecanoate, 4-benzyloxyphenylethyl pentadecanoate, 4-benzyloxyphenylethyl hexadecanoate, 4-benzyloxy heptadecanoate Examples include phenylethyl, 4-benzyloxyphenylethyl octadecanoate, and the like.

（式中、Ｒは炭素数８以上のアルキル基またはアルケニル基を示し、ｍおよびｎはそれぞれ独立して、１～３の整数を示し、ＸおよびＹはそれぞれ独立して、水素原子、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基、ハロゲン原子のいずれかを示す。） Furthermore, a compound represented by the following formula (3) may be used as the component (c).

(Wherein, R represents an alkyl group or alkenyl group having 8 or more carbon atoms, m and n each independently represent an integer of 1 to 3, X and Y each independently represent a hydrogen atom, a carbon number 1 to 4 alkyl groups, C 1 to 4 alkoxy groups, or halogen atoms.)

Examples of compounds represented by formula (3) include 1,1-diphenylmethyl octanoate, 1,1-diphenylmethyl nonanoate, 1,1-diphenylmethyl decanoate, 1,1-diphenylmethyl undecanoate, and dodecane. 1,1-diphenylmethyl acid, 1,1-diphenylmethyl tridecanoate, 1,1-diphenylmethyl tetradecanoate, 1,1-diphenylmethyl pentadecanoate, 1,1-diphenylmethyl hexadecanoate, 1,1-heptadecanoate Examples include diphenylmethyl, 1,1-diphenylmethyl octadecanoate, and the like.

（式中、Ｘは水素原子、炭素数１～４のアルキル基、メトキシ基、ハロゲン原子のいずれかを示し、ｍは１～３の整数を示し、ｎは１～２０の整数を示す。） Furthermore, a compound represented by the following formula (4) may be used as the component (c).

(Wherein, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, or a halogen atom, m represents an integer of 1 to 3, and n represents an integer of 1 to 20.)

Examples of the compound represented by formula (4) include diesters of malonic acid and 2-[4-(4-chlorobenzyloxy)phenyl]ethanol, and succinic acid and 2-(4-benzyloxyphenyl)ethanol. Diesters, diesters of succinic acid and 2-[4-(3-methylbenzyloxy)phenyl]ethanol, diesters of glutaric acid and 2-(4-benzyloxyphenyl)ethanol, glutaric acid and 2-[4-( 4-chlorobenzyloxy)phenyl]ethanol, diesters of adipic acid and 2-(4-benzyloxyphenyl)ethanol, diesters of pimelic acid and 2-(4-benzyloxyphenyl)ethanol, suberic acid and 2-(4-benzyloxyphenyl)ethanol diester, suberic acid diester with 2-[4-(3-methylbenzyloxy)phenyl]ethanol, suberic acid with 2-[4-(4-chlorobenzyloxy ) phenyl] ethanol, diester of suberic acid with 2-[4-(2,4-dichlorobenzyloxy)phenyl]ethanol, diester of azelaic acid with 2-(4-benzyloxyphenyl)ethanol, sebacine diester of acid with 2-(4-benzyloxyphenyl)ethanol, diester of 1,10-decanedicarboxylic acid with 2-(4-benzyloxyphenyl)ethanol, 1,18-octadecanedicarboxylic acid with 2-(4 -benzyloxyphenyl)ethanol, diesters of 1,18-octadecanedicarboxylic acid and 2-[4-(2-methylbenzyloxy)phenyl]ethanol, and the like.

（式中、Ｒは炭素数１～２１のアルキル基またはアルケニル基を示し、ｎは１～３の整数を示す。） Furthermore, a compound represented by the following formula (5) may be used as the component (c).

(Wherein, R represents an alkyl or alkenyl group having 1 to 21 carbon atoms, and n represents an integer of 1 to 3.)

Examples of the compound represented by formula (5) include a diester of 1,3-bis(2-hydroxyethoxy)benzene and capric acid and a diester of 1,3-bis(2-hydroxyethoxy)benzene and undecanoic acid. , a diester of 1,3-bis(2-hydroxyethoxy)benzene and lauric acid, a diester of 1,3-bis(2-hydroxyethoxy)benzene and myristic acid, a diester of 1,4-bis(hydroxymethoxy)benzene and Diesters of butyric acid, diesters of 1,4-bis(hydroxymethoxy)benzene with isovaleric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene with acetic acid, 1,4-bis(2-hydroxy ethoxy)benzene with propionic acid, 1,4-bis(2-hydroxyethoxy)benzene with valeric acid, 1,4-bis(2-hydroxyethoxy)benzene with caproic acid, 1, Diesters of 4-bis(2-hydroxyethoxy)benzene and caprylic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and capric acid, 1,4-bis(2-hydroxyethoxy)benzene and laurin Examples include diesters with acids, diesters with 1,4-bis(2-hydroxyethoxy)benzene and myristic acid, and the like.

（式中、Ｘは水素原子、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基、ハロゲン原子のいずれかを示し、ｍは１～３の整数を示し、ｎは１～２０の整数を示す。） Furthermore, a compound represented by the following formula (6) may be used as the component (c).

(Wherein, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; m represents an integer of 1 to 3; n represents 1 to 20 indicates an integer of

Examples of the compound represented by formula (6) include a diester of succinic acid and 2-phenoxyethanol, a diester of suberic acid and 2-phenoxyethanol, a diester of sebacic acid and 2-phenoxyethanol, and 1,10-decanedicarboxylic acid. and 2-phenoxyethanol, and diesters of 1,18-octadecanedicarboxylic acid and 2-phenoxyethanol.

（式中、Ｒは炭素数４～２２のアルキル基、シクロアルキルアルキル基、シクロアルキル基、炭素数４～２２のアルケニル基のいずれかを示し、Ｘは水素原子、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基、ハロゲン原子のいずれかを示し、ｎは０または１を示す。） Furthermore, a compound represented by the following formula (7) may be used as the component (c).

(Wherein, R represents an alkyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, a cycloalkyl group, or an alkenyl group having 4 to 22 carbon atoms, X is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, group, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, and n is 0 or 1.)

Examples of the compound represented by formula (7) include decyl 4-phenylbenzoate, lauryl 4-phenylbenzoate, myristyl 4-phenylbenzoate, cyclohexylethyl 4-phenylbenzoate, octyl 4-biphenylacetate, 4- nonyl biphenylacetate, decyl 4-biphenylacetate, lauryl 4-biphenylacetate, myristyl 4-biphenylacetate, tridecyl 4-biphenylacetate, pentadecyl 4-biphenylacetate, cetyl 4-biphenylacetate, cyclopentyl 4-biphenylacetate, 4-biphenylacetate Examples include cyclohexylmethyl, 4-biphenylhexylacetate, 4-biphenylacetate cyclohexylmethyl and the like.

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

(Wherein, R represents an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms, X represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms , a halogen atom, Y is a hydrogen atom or a methyl group, and Z is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, or a halogen atom. )
Examples of compounds represented by formula (8) include phenoxyethyl 4-butoxybenzoate, phenoxyethyl 4-pentyloxybenzoate, phenoxyethyl 4-tetradecyloxybenzoate, phenoxyethyl 4-hydroxybenzoate and dodecanoic acid. and dodecyl ether of phenoxyethyl vanillate.

（式中、Ｒは炭素数４～２２のアルキル基、炭素数４～２２のアルケニル基、シクロアルキルアルキル基、シクロアルキル基のいずれかを示し、Ｘは水素原子、アルキル基、アルコキシ基、ハロゲン原子のいずれかを示し、Ｙは水素原子、アルキル基、アルコキシ基、ハロゲン原子のいずれかを示し、ｎは０または１を示す。） Furthermore, a compound represented by the following formula (9) may be used as the component (c).

(Wherein, R represents an alkyl group having 4 to 22 carbon atoms, an alkenyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, or a cycloalkyl group, and X represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, Y is a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and n is 0 or 1.)

Examples of the compound represented by formula (9) include benzoate of octyl 4-hydroxybenzoate, decyl 4-hydroxybenzoate, 4-methoxy benzoate of heptyl 4-hydroxybenzoate, 4 2-methoxybenzoate of dodecyl-hydroxybenzoate, benzoate of cyclohexylmethyl-4-hydroxybenzoate, and the like can be exemplified.

（式中、Ｒは炭素数３～１８のアルキル基、炭素数６～１１のシクロアルキルアルキル基、炭素数５～７のシクロアルキル基、炭素数３～１８のアルケニル基のいずれかを示し、Ｘは水素原子、炭素数１～４のアルキル基、炭素数１～３のアルコキシ基、ハロゲン原子のいずれかを示し、Ｙは水素原子、炭素数１～４のアルキル基、メトキシ基、エトキシ基、ハロゲン原子のいずれかを示す。） Further, the component (c) may be a compound represented by the following formula (10).

(Wherein, R represents an alkyl group having 3 to 18 carbon atoms, a cycloalkylalkyl group having 6 to 11 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or an alkenyl group having 3 to 18 carbon atoms, X is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a halogen atom; Y is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, or an ethoxy group; , indicates one of the halogen atoms.)

Examples of the compound represented by formula (10) include phenoxyethyl ether of nonyl 4-hydroxybenzoate, phenoxyethyl ether of decyl 4-hydroxybenzoate, phenoxyethyl ether of undecyl 4-hydroxybenzoate, and dodecyl vanillate. Phenoxyethyl ether etc. can be illustrated.

（式中、Ｒは炭素数３～８のシクロアルキル基または炭素数４～９のシクロアルキルアルキル基を示し、ｎは１～３の整数を示す。） Furthermore, a compound represented by the following formula (11) may be used as the component (c).

(Wherein, R represents a cycloalkyl group having 3 to 8 carbon atoms or a cycloalkylalkyl group having 4 to 9 carbon atoms, and n represents an integer of 1 to 3.)

Examples of the compound represented by formula (11) include diesters of 1,3-bis(2-hydroxyethoxy)benzene and cyclohexanecarboxylic acid, and 1,4-bis(2-hydroxyethoxy)benzene and cyclohexanepropionic acid. and diesters of 1,3-bis(2-hydroxyethoxy)benzene and cyclohexanepropionic acid.

（式中、Ｒは炭素数３～１７のアルキル基、炭素数３～８のシクロアルキル基、炭素数５～８のシクロアルキルアルキル基のいずれかを示し、Ｘは水素原子、炭素数１～５のアルキル基、メトキシ基、エトキシ基、ハロゲン原子のいずれかを示し、ｎは１～３の整数を示す。） Furthermore, a compound represented by the following formula (12) may be used as the component (c).

(Wherein, R is an alkyl group having 3 to 17 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, or a cycloalkylalkyl group having 5 to 8 carbon atoms; X is a hydrogen atom; 5, an alkyl group, a methoxy group, an ethoxy group, or a halogen atom, and n is an integer of 1 to 3.)

Examples of the compound represented by formula (12) include diesters of 4-phenylphenol ethylene glycol ether and cyclohexanecarboxylic acid, diesters of 4-phenylphenol diethylene glycol ether and lauric acid, and 4-phenylphenol triethylene glycol ether. Diesters of cyclohexanecarboxylic acid, diesters of 4-phenylphenol ethylene glycol ether and octanoic acid, diesters of 4-phenylphenol ethylene glycol ether and nonanoic acid, diesters of 4-phenylphenol ethylene glycol ether and decanoic acid, 4 - A diester of phenylphenol ethylene glycol ether and myristic acid can be exemplified.

Furthermore, as an electron-accepting compound, a specific alkoxyphenol compound having a linear or side-chain alkyl group having 3 to 18 carbon atoms is used (JP-A-11-129623, JP-A-11-5973), or a specific Using a hydroxybenzoic acid ester (JP-A-2001-105732), using a gallic acid ester (JP-B-51-44706, JP-A-2003-253149) heat coloring type (coloring by heating, It is also possible to apply a reversible thermochromic composition that decolorizes by cooling (see FIG. 3).

The above reversible thermochromic composition is a compatible body containing the above (a) component, (b) component, and (c) component as essential components, and the ratio of each component is the concentration, color change temperature, color change form Although it depends on the type of each component, generally the component ratio at which the desired properties can be obtained is 0.1 to 100, preferably 0.1 to 50 , more preferably 0.5 to 20, component (c) 5 to 200, preferably 5 to 100, more preferably 10 to 100 (all the above proportions are parts by mass).

Furthermore, various light stabilizers may be added to the reversible thermochromic composition, if necessary.
The light stabilizer is contained in order to prevent photodegradation of the reversible thermochromic composition consisting of component (a), component (b), and component (c). 0.3 to 24% by mass, preferably 0.3 to 16% by mass. Among the light stabilizers, the ultraviolet absorber effectively cuts ultraviolet rays contained in sunlight or the like, and prevents photodegradation caused by the excited state due to the photoreaction of the component (a). In addition, antioxidants, singlet oxygen quenchers, superoxide anion quenchers, ozone quenchers and the like suppress the oxidation reaction caused by light.
The light stabilizer may be used alone, or two or more of them may be used in combination.

In the present invention, microcapsules have a specific structure. The specific structure is expressed by the average particle size (X) and the average cross-sectional film thickness (Y) of the microcapsules contained in the microcapsule pigment or the microcapsules contained in the ink composition.

In the present invention, an average particle size (median size) based on volume is used as the average particle size.
As an optimum method for measuring the average particle size, a laser diffraction/scattering particle size distribution measuring device calibrated by a direct measurement method, for example, a laser diffraction particle size distribution measuring device LA-300 (trade name, Horiba Co., Ltd. manufactured by Seisakusho).

As a direct measurement method used for calibration,
(i) an image analysis method in which the area (two-dimensional) of individual particles is measured from an image taken with a microscope to measure the equivalent diameter;
(ii) Coulter method (Electrical sensing band The laser measurement method is calibrated based on the values obtained by these methods.

Measurement of the average particle size by the image analysis method, for example, using the image analysis type particle size distribution measurement software "Macview" (trade name, manufactured by Mountec Co., Ltd.) to determine the particle area, projected from the area of the particle area The area circle equivalent diameter (Heywood diameter) can be calculated, and the average particle diameter of particles equivalent to a sphere of equal volume can be measured.
In addition, the measurement of the average particle size by the Coulter method is applicable when the particle size of all particles or most of the particles exceeds 0.2 μm. It can be measured using the device "Multisizer 4e".

Further, for the microcapsule pigment contained in the ink composition according to the present invention, the average cross-sectional film thickness (Y) of the microcapsules is specified. The cut cross-sectional film thickness can be obtained by image analysis of a cross-sectional image of the frozen microcapsule pigment. in particular,
(i) freezing a dispersion of microcapsule pigments, such as an aqueous dispersion,
(ii) prepare a thin section sample with a thickness of 50 μm by a microtome,
(iii) Observing a field of view with about 100 to 200 microcapsules in the field of view with a transmission electron microscope, for example, HT7700 (trade name, manufactured by Hitachi High-Tech Co., Ltd.),
(iv) measuring the area of the region surrounded by the outer periphery of the coating cross section and the area of the region surrounded by the inner periphery of the coating cross section for each microcapsule in the field of view;
(v) Calculate the cross-sectional outer diameter and the cross-sectional inner peripheral diameter from the two areas obtained,
(vi) for all microcapsules in the field of view,
Cut cross-section film thickness = (cross-section outer diameter - cross-section inner diameter) / 2
Based on, the cut cross-sectional film thickness is calculated, and the average value is taken as the average cut cross-sectional film thickness.
Determination of the cross-sectional outer diameter and the cross-sectional inner diameter in (iv) and (v) can be performed by the image analysis software described above.
In addition, the calculation of the average cross-sectional film thickness in the present invention is intended for capsules for which the cross-sectional film thickness has been measured and calculated by the above (iv) and (v).

In the present invention, the cut cross-sectional film thickness does not simply correspond to the thickness of the microcapsule coating, but is a parameter different from the film thickness. It is generally very difficult to measure the coating thickness of microcapsules. This is because, in order to directly observe the thickness of the coating, it is necessary to observe a cut plane passing through the center of the microcapsule. However, it is difficult to obtain such a cross section for all microcapsules with a particle size distribution. Furthermore, although microcapsules often have a shape close to a sphere, they may become deformed due to expansion or contraction of the inclusions, and it may be difficult to determine the center of the microcapsule. These reasons combine to make it difficult to measure coating thickness. On the other hand, in the present invention, instead of the thickness of the film, attention is focused on the thickness of the cut cross-section. This cut cross-sectional film thickness does not match the film thickness. This is because, in many cases, the cutting plane formed during thin section sample preparation does not pass through the center of the microcapsules to be cut. In addition, since actual microcapsules have a distribution of particle diameters, it becomes difficult to measure the particle diameter of the microcapsules and the thickness of the film.

On the other hand, the present invention was completed based on the finding that the ink composition exhibits excellent effects when such parameters and the average particle size satisfy certain conditions.
First, the microcapsules contained in the ink composition according to the present invention have a volume-based average particle diameter (X) of 0.1 to 3.0 μm, preferably 0.3 to 2.0 μm, and more preferably. is 0.3 to 1.5 μm, more preferably 0.3 to 1.0 μm. If the volume-based average particle diameter (X) of the microcapsules is excessively small, the color density generally tends to decrease, and if it is excessively large, it causes sedimentation of the microcapsules and deterioration of the ink ejection property of the writing instrument. It is necessary to be careful because there is a Therefore, when the volume-based average particle size (X) is within the above range, it is possible to improve the dispersion stability of the ink composition and the ink ejection property with a writing instrument while maintaining the color density.

Moreover, in order to maintain the ejection property and ejection stability from the nib of the ink composition, it is preferable that the content of coarse microcapsules is small. Specifically, the content of microcapsules with a particle diameter of 8 μm or more (hereinafter sometimes referred to as “large particle content”) is 1% by volume or less based on the total volume of microcapsules in the microcapsule pigment. Preferably.

Further, the microcapsules contained in the ink composition according to the present invention have an average cut surface thickness (Y) of 0.02 to 0.7 μm, preferably 0.04 to 0.6 μm, and preferably 0.05 to 0.05 μm. It is more preferably 0.5 μm. A reversible thermochromic microcapsule pigment having an excellent balance between durability and color density can be obtained by keeping the average cut surface thickness (Y) within an appropriate range.

Furthermore, the microcapsules contained in the ink composition according to the present invention preferably have a ratio Y/X between the average particle diameter (X) and the average cross-sectional thickness (Y) satisfying the following formula (1), and (1a) It is more preferable to satisfy (1b), and sometimes it is preferable to satisfy (1b). The ratio Y/X preferably satisfies the following formula (2), more preferably satisfies (2a), and sometimes preferably satisfies (2b). By setting the ratio Y/X within an appropriate range, it is possible to obtain a reversible thermochromic microcapsule pigment having an excellent balance between durability and dispersion stability of the ink composition while maintaining color density.
Y/X<0.3 (1)
Y/X<0.25 (1a)
Y/X<0.2 (1b)
0.02<Y/X (2)
0.03<Y/X (2a)
0.04<Y/X (2b)

[Method for producing microcapsules]
The microcapsule pigment used in the ink composition according to the present invention comprises microcapsules in which the reversible thermochromic composition containing the above components (a), (b) and (c) is encapsulated in a coating. .

By encapsulating the reversible thermochromic composition in microcapsules, a chemically and physically stable pigment can be constructed, and the reversible thermochromic composition can be maintained at the same composition under various conditions of use. The same action and effect can be obtained.

In addition, microencapsulation can be performed by conventionally known isocyanate-based interfacial polymerization methods, melamine-formalin-based in situ polymerization methods, in-liquid curing coating methods, phase separation methods from aqueous solutions, phase separation methods from organic solvents, and melting. Depending on the application, the method may be appropriately selected from production methods such as a dispersion cooling method, an air suspension coating method, and a spray drying method. Furthermore, depending on the purpose, the surface of the microcapsules may be further provided with a secondary resin film to impart durability, or the surface characteristics may be modified for practical use.

In the microcapsule pigment used in the ink composition of the present invention, the average particle diameter (X) and the average cross-sectional thickness (Y) of the microcapsules contained in the microcapsule pigment must satisfy specific conditions. . In order to meet specific requirements, it is necessary to adjust the microcapsule manufacturing conditions.
As described above, there are various methods for producing microcapsules, and appropriate conditions vary according to each method. It also varies depending on the components that constitute the reversible thermochromic composition used and the components that form the microcapsule coating. For this reason, in order to produce the microcapsules according to the present invention, it is common practice to create a calibration curve for different production conditions and search for optimum conditions within the calibration curve.

For example, when trying to produce microcapsules by an interfacial polymerization method, the average particle diameter (X) and average cross-sectional thickness (Y) of the microcapsules are the polymerization temperature, the polymerization time, the reversible thermochromic composition and the coating material. and the stirring speed of the reaction solution. Several types of microcapsules are produced by changing only one of these parameters, and the average particle size (X) and average cross-sectional film thickness (Y) are measured to create a calibration curve. When the production conditions for the desired microcapsules cannot be determined only by the calibration curve, another parameter is changed to create a calibration curve. In this manner, microcapsules having a desired average particle size (X) and average cross-sectional thickness (Y) can be produced.

[Reversible thermochromic ink composition for writing instrument and writing instrument containing the same]
A reversible thermochromic ink composition for writing instruments according to the present invention comprises a microcapsule pigment and a vehicle.
The blending ratio of the microcapsule pigment in the ink composition is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 40% by mass, based on the total mass of the ink composition. is more preferable, and 10 to 30% by mass is even more preferable. When the blending ratio of the microcapsule pigment is within the above range, it is possible to obtain the desired color density and to prevent deterioration of the ink ejection property.

Vehicles commonly used for writing instruments can be used. For example, one containing water and/or an organic solvent and, if necessary, various additives can be used. By dispersing the microcapsule pigment in a vehicle to form an ink composition, it is possible to prepare ink compositions for ballpoint pens, marking pens, fountain pens, brush pens, calligraphy pens, and the like.
A writing instrument according to the present invention accommodates this ink composition.

The vehicle includes an oily vehicle containing an organic solvent, or an aqueous vehicle containing water and, if necessary, an organic solvent. An aqueous vehicle is preferable as the vehicle applied to the present invention. When the vehicle is an aqueous vehicle, the ink composition may contain a water-soluble organic solvent that is compatible with water. The water-soluble organic solvent suppresses evaporation of water in the ink, prevents variation in the specific gravity of the vehicle, and maintains good dispersion stability of the microcapsule pigment. It can stabilize the structure of the loose aggregates formed by the dispersant.

The organic solvent is not particularly limited, and for example,
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol monophenyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, 3-methoxybutanol, 3-methoxy-3 - glycol ether solvents such as methylbutanol,
glycol solvents such as diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, ethylene glycol, thioethylene glycol;
benzyl alcohol, methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, tert-butanol, propargyl alcohol, allyl alcohol, 3-methyl-1-butyn-3-ol, ethylene glycol monomethyl ether acetate, alcohol solvents such as glycerin, sorbitol and other higher alcohols;
alcohol amines such as triethanolamine, diethanolamine, monoethanolamine, etc.;
Examples include sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone and the like.

The organic solvent can be used alone or in combination of two or more.
When the ink composition according to the present invention contains a water-soluble organic solvent, the blending ratio of the water-soluble organic solvent is not particularly limited, but should be 1 to 40% by mass based on the total mass of the ink composition. is preferred, 5 to 30 mass % is more preferred, and 10 to 25 mass % is even more preferred. If the blending ratio of the water-soluble organic solvent exceeds 40% by mass, the viscosity of the ink tends to increase. On the other hand, if the blending ratio is less than 1% by mass, the effect of suppressing water evaporation is poor.

Water is not particularly limited, and examples thereof include tap water, ion-exchanged water, ultrafiltered water, and distilled water.
The blending ratio of the organic solvent or water is not particularly limited, but is preferably 10 to 90% by mass, more preferably 30 to 80% by mass, based on the total mass of the ink composition. .

Additives suitable for the purpose and type of writing instrument can be added to the vehicle. Additives contained in the vehicle include shear thinning agents, polymer flocculants, dispersants, water-soluble resins, specific gravity adjusters, surfactants, rust inhibitors, pH adjusters, bubble absorbers, wetting agents, Antifoaming agent, cross-linking agent, curing agent, desiccant, plasticizer, viscosity modifier, UV absorber, antioxidant, light stabilizer, anti-settling agent, smoothing agent, gelling agent, matting agent, penetrating agent, foaming agents, coupling agents, moisturizing agents, antifungal agents, antiseptics, antirust agents, and the like.

Ink compositions include shear thinning inks (gel inks) that include a shear thinning agent in the vehicle.

The shear thinning property is a property that the viscosity is high when left standing, and the viscosity decreases when a shearing stress is applied. Shear-thinning ink is highly viscous when left stationary without shear stress. The viscosity of the ink composition in the vicinity of the ball is lowered by the stress, and as a result, the ink composition is ejected from the gap between the ball and the ball accommodating portion and adheres to the non-writing surface.

In addition, the shear-thinning ink can suppress aggregation and sedimentation of the microcapsule pigment, and can suppress bleeding of handwriting, so that good handwriting can be formed. Furthermore, the ball-point pen containing the shear-thinning ink composition prevents ink leakage from the gap between the ball and the tip when not in use, and the ink composition when left with the writing tip facing upward (upright state). backflow can be prevented.

Shear-thinning agents include, for example, water-soluble polysaccharides, polymers having a molecular weight of 100,000 to 150,000 mainly composed of alkyl esters of methacrylic acid, poly-N-vinylcarboxylic acid amide cross-linked products, benzylidene sorbitol and their Examples include derivatives, benzylidene xylitol and its derivatives, alkali-thickening acrylic resins, crosslinkable acrylic acid polymers, inorganic fine particles, nonionic surfactants with an HLB value of 8 to 12, metal salts and amine salts of dialkylsulfosuccinic acid, etc. can.

The shear thinning agent can be used alone or in combination of two or more.

Examples of water-soluble polysaccharides include xanthan gum, welan gum, zetasea gum, diutan gum, macrohomopsis gum, and succinoglycan (average molecular weight of about 1 million to 8 million), guar gum, locust bean gum and its derivatives, hydroxyethylcellulose, alginic acid alkyl esters, glucomannan, carbohydrates with gelling ability extracted from seaweed such as agar and carrageenin.

When the vehicle according to the present invention contains a shear thinning agent, the blending ratio of the shear thinning agent is not particularly limited, but is 0.1 to 20% by mass based on the total mass of the ink composition. Preferably.

Ink compositions also include flocculating inks containing polymeric flocculants in the vehicle.
In an ink composition containing a polymer flocculant (aggregating ink), microcapsule pigments form loose aggregates via the polymer flocculant, and the microcapsule pigments are prevented from coming into contact with each other and flocculating. Therefore, the dispersibility of the microcapsule pigment can be improved.

Polymer flocculants include polyvinylpyrrolidone, polyethylene oxide, water-soluble polysaccharides, and the like.

Examples of water-soluble polysaccharides include tragacanth gum, guar gum, pullulan, cyclodextrin, and water-soluble cellulose derivatives.

Furthermore, examples of water-soluble cellulose derivatives include methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose and the like.

Among the above polymer flocculants, hydroxyethyl cellulose is preferable because of its excellent dispersibility.

Specifically, as the polymer flocculant, manufactured by Sumitomo Seika Co., Ltd., product names: HEC A grade, HEC S grade, HEC CF grade, Daicel Finechem Co., Ltd., product names: HEC Daicel SP type, HEC Daicel SE type, The same EE type, manufactured by Dow Chemical Japan Co., Ltd., product name: CELLOSIZE WP type, the same QP type, the same EP type, manufactured by Sansho Co., Ltd., product name: SANHEC, etc. can be exemplified.

When the vehicle according to the present invention contains a polymer flocculant, the blending ratio of the polymer flocculant is not particularly limited, but should be 0.1 to 1% by mass based on the total mass of the ink composition. is preferred, and 0.3 to 0.5% by mass is more preferred. Within the above range, the microcapsule pigment forms loose aggregates, and the effect of improving the dispersibility of the microcapsule pigment can be sufficiently exhibited.

The ink composition according to the present invention can contain a dispersant to enhance the dispersibility of the microcapsule pigment in the ink composition.
In addition, a polymer flocculant and a dispersant can be used in combination, and when both are used in combination, the dispersibility of the microcapsule pigment in the ink composition can be improved, and the microcapsule pigment can be formed via the polymer flocculant. It is possible to further improve the dispersibility of loose aggregates of microcapsule pigments.

Dispersants include, for example, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl ether, styrene-maleic acid copolymers, ketone resins, hydroxyethyl cellulose and its derivatives, synthetic resins such as styrene-acrylic acid copolymers, acrylic polymers, Examples include PO/EO adducts and polyester amine-based oligomers.

Among the above-described dispersants, acrylic polymer dispersants are preferable, and acrylic polymer dispersants having carboxy groups are more preferable, since they are excellent in dispersibility of microcapsule pigments. is more preferable.
Especially preferred as the dispersant is an acrylic polymer dispersant having a comb-shaped structure having a plurality of carboxyl groups in the side chains.

When the ink composition according to the present invention contains a dispersant, the blending ratio of the dispersant is not particularly limited, but it is preferably 0.01 to 2% by mass based on the total mass of the ink composition. , more preferably 0.1 to 1.5% by mass. If the blending ratio of the dispersant exceeds 2% by mass, the microcapsule pigment tends to settle or float when vibration or the like is applied from the outside. On the other hand, if the blending ratio is less than 0.01% by mass, the effect of improving the dispersibility is difficult to manifest.

Water-soluble resins such as alkyd resins, acrylic resins, styrene-maleic acid copolymers, cellulose derivatives, polyvinylpyrrolidone, polyvinyl alcohol and dextrin can be blended into the ink composition according to the present invention. In addition, it is possible to impart stickiness and viscosity to the paper surface.
The water-soluble resin can be used alone or in combination of two or more.

When the ink composition according to the present invention contains an acrylic polymer dispersant, polyvinyl alcohol is preferable among the above water-soluble resins because the stability of the acrylic polymer dispersant is excellent. Further, partially saponified polyvinyl alcohol having a degree of saponification of 70 to 89 mol % is more preferable because the ink composition is highly soluble even in an acidic region.
When the ink composition according to the present invention contains a water-soluble resin, the blending ratio of the water-soluble resin is not particularly limited, but should be 0.3 to 3% by mass based on the total mass of the ink composition. is preferred, and 0.5 to 1.5% by mass is more preferred.

The ink composition according to the present invention can be blended with a specific gravity adjuster, and when the viscosity of the vehicle is low, microcapsule pigments are contained in the composition in the ink when the ink composition receives an external stimulus such as vibration. can be suppressed from localizing by settling or surfacing.

The specific gravity of microcapsule pigments depends on the particle size of the microcapsules contained in the microcapsule pigments, the ingredients contained in the microcapsules and their content, the ingredients and film thickness of the capsule coating, the color development state of the microcapsule pigments, and the temperature. However, its specific gravity is preferably 1.05 to 1.20, more preferably 1.10 to 1, when the microcapsule pigment is in a completely colored state and water is used as a reference substance in an environment of 20 ° C. .20, more preferably in the range of 1.12 to 1.15. In addition, microcapsule pigments with a large hysteresis width (ΔH) often use the component (C) having two or more aromatic rings in the molecule, and have a large specific gravity as described above. In an ink composition containing a specific gravity modifier, even if the viscosity of the vehicle is low, the microcapsule pigment settles or floats in the ink composition when subjected to external vibrations during transportation, etc. is suppressed.
Incidentally, the specific gravity of the microcapsule pigment can be measured by the following method.

(Method for measuring specific gravity of microcapsule pigment)
1. 30 ml of an aqueous glycerin solution and 1 g of a completely colored microcapsule pigment are put into a screw tube bottle and mixed to obtain a microcapsule pigment dispersion.
2. 30 ml of the microcapsule pigment dispersion is adjusted to 20° C. and centrifuged at 1000 rpm for 30 seconds. As the centrifuge, a cooling/desktop centrifuge "H103N" (trade name, manufactured by Kokusan Co., Ltd.) can be used.
3. Observe the microcapsule pigment dispersion.
If most of the microcapsule pigment is precipitated at the bottom of the beaker, an aqueous solution with a higher glycerin concentration than the glycerin aqueous solution at this time is used, and operations 1 and 2 are repeated to observe the state of the dispersion.

If it is confirmed that most of the microcapsule pigment is floating on the liquid surface, use an aqueous solution with a lower glycerin concentration than the glycerin aqueous solution at this time, and repeat the operations 1 and 2 to observe the state of the dispersion. .

The above series of operations is not a state in which most of the microcapsule pigment is floating or sedimenting on the liquid surface, but the area other than the liquid surface of the glycerin aqueous solution and the vicinity of the bottom of the screw tube bottle is uniformly colored. Repeat until the condition is visually confirmed. When this state is observed, the specific gravity of the glycerin aqueous solution is measured and taken as the specific gravity of the microcapsule pigment. The specific gravity of the glycerin aqueous solution can be measured by the float method described in Section 7.1 of JIS K0061 with the temperature of the aqueous solution adjusted to 20°C.

The sedimentation and floating stability of the microcapsule pigment is maximized when the difference in specific gravity between the vehicle and the microcapsule pigment is minimal, and the specific gravity modifier brings the specific gravity of the vehicle close to that of the microcapsule pigment. Since the specific gravity of the vehicle depends on the specific gravity of the water-soluble substance dissolved in the vehicle and the amount added, the specific gravity of the vehicle can be increased by adding a larger amount of a specific gravity adjuster having a large specific gravity to the vehicle and dissolving it. You can make it bigger.

Examples of the specific gravity adjuster include those that can be dissolved in the vehicle and adjusted so that the specific gravity of the vehicle approaches the specific gravity of the microcapsule pigment. Salt can be exemplified.

The above-mentioned oxyacids and salts thereof are selected from the group consisting of oxyacids of transition metal elements and salts thereof, and the oxyacid ions are tetrahedrons in which oxygen atoms are usually 4- or 6-coordinated to a metal atom or the like. Or it is said to form an octahedron.
The tetrahedral or octahedral unit may be a single unit or a polyacid having a structure in which they are bonded via edges and vertices, and a polyacid salt thereof. Polyacids are polyacids formed by the condensation of oxyacids of metal elements. Polyacids composed of only one type of metal and having all the condensed anions of the same type are called isopolyacids. A polyacid condensed with is called a heteropolyacid. And each salt is called an isopolyacid salt and a heteropolyacid salt. The above polyacids include isopolyacids, heteropolyacids and the like, and the above polyacid salts include isopolyacid salts, heteropolyacid salts and the like.

Specific gravity adjusting agents include single oxyacids and salts thereof, isopolyacids and salts thereof, heteropolyacids and salts thereof, and the like.
Examples of single oxyacids include molybdic acid, tungstic acid, and the like, and examples of single oxyacid salts include sodium molybdate, potassium molybdate, ammonium molybdate, sodium tungstate, potassium tungstate, and tungsten. Examples include ammonium tungstate, lithium tungstate, and magnesium tungstate.

Examples of isopolyacids include metamolybdic acid, paramolybdic acid, metatungstic acid, paratungstic acid, and isotungstic acid. Ammonium molybdate, sodium paramolybdate, potassium paramolybdate, ammonium paramolybdate, sodium metatungstate, potassium metatungstate, ammonium metatungstate, barium metatungstate, sodium paratungstate, sodium isotungstate, etc. I can give an example.
Examples of heteropolyacids include molybdophosphoric acid, molybdosilicic acid, tungstophosphoric acid, and tungstosilicic acid. Examples of heteropolyacid salts include sodium molybdophosphate, sodium molybdosilicate, sodium tungstophosphate, and sodium tungstosilicate. I can give an example.
The above oxyacids and salts thereof can be used singly or in combination of two or more.

Among the above specific gravity adjusting agents, metatungstic acid, paratungstic acid, sodium metatungstate, potassium metatungstate, ammonium metatungstate, barium metatungstate, sodium paratungstate, sodium isotungstate, tungstic acid, Preferred are tungstosilicate, sodium tungstophosphate, and sodium tungstosilicate, and more preferred are sodium isotungstate, sodium metatungstate, and sodium paratungstate.
The above sodium isotungstate, sodium metatungstate, and sodium paratungstate are not only highly safe but also have a high specific gravity. , is preferred.

When the ink composition according to the present invention contains a specific gravity modifier, the blending ratio of the specific gravity modifier is not particularly limited, but is preferably 2 to 20% by mass based on the total mass of the ink composition. , more preferably 5 to 15% by mass. If the blending ratio of the specific gravity modifier exceeds 20% by mass, the microcapsule pigment tends to aggregate. On the other hand, if the blending ratio of the specific gravity modifier is less than 2% by mass, the effect of adjusting the specific gravity of the vehicle becomes poor.
The mass ratio of the microcapsule pigment to the specific gravity modifier is preferably 0.05 to 4.0, more preferably 0.075 to 2.0, still more preferably 0.1 to 1.5.

The ink composition according to the present invention can be blended with a surfactant to adjust the surface tension of the ink composition to an appropriate range.
Surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and the like, and any of them can be suitably used.

Examples of surfactants include phosphate ester surfactants, silicone surfactants, surfactants having an acetylene bond in their structure, fluorine surfactants, and the like. It is appropriately selected according to the components of the ink composition, the application, and the like.
When the ink composition according to the present invention contains a surfactant, the blending ratio of the surfactant is not particularly limited, but should be 0.01 to 2% by mass based on the total mass of the ink composition. is preferred, and 0.05 to 1% by mass is more preferred.

When the hysteresis width (ΔH) of the microcapsule pigment compounded in the ink composition is large, its specific gravity is greater than 1. When adjusting the specific gravity of the vehicle, a water-soluble organic solvent having a larger specific gravity than water can be used to adjust the specific gravity. As the water-soluble organic solvent, it is preferable to use glycerin or the like having a specific gravity of more than 1.1.

The ink composition according to the present invention may also contain other additives, if necessary. Other additives include, for example,
Rust inhibitors such as benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, saponin, etc.
carbolic acid, sodium salt of 1,2-benzothiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl parahydroxybenzoate, 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine preservatives or fungicides such as
pH adjusters such as ammonia, sodium carbonate, sodium hydrogen phosphate, potassium hydrogen phosphate, sodium hydroxide, potassium hydroxide, sodium acetate, monoethanolamine, diethanolamine, and triethanolamine;
Ascorbic acids, erythorbic acids, α-tocopherol, catechins, synthetic polyphenols, kojic acid, alkyl hydroxylamines, oxime derivatives, α-glucosylrutin, α-lipoic acid, phosphonates, phosphinates, sulfites, sulfoxylates , dithionite, thiosulfate, thiourea dioxide and other foam absorbents,
Wetting agents such as reduced or non-reduced starch hydrolysates, disaccharides such as trehalose, oligosaccharides, sucrose, cyclodextrin, glucose, dextrin, sorbitol, mannitol, and sodium pyrophosphate,
Antifoaming agents and the like can be exemplified.

Moreover, when the ink composition according to the present invention is contained in a ball-point pen, it is preferable that the ink composition contains a lubricant. The lubricant improves the lubricity between the ball seat provided inside the tip body and the ball provided at the front end of the tip body, thereby easily preventing wear of the ball seat and improving the writing feel. It is something that can be done.

Examples of lubricants include higher fatty acids such as oleic acid, nonionic surfactants having long-chain alkyl groups, polyether-modified silicone oils, tri(alkoxycarbonylmethyl) thiophosphite and tri(alkoxycarbonyl) thiophosphite. thiophosphite triesters such as ethyl esters), phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, phosphoric acid diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, and metals thereof Phosphate surfactants such as salts, ammonium salts, amine salts, and alkanolamine salts can be exemplified.

When the ink composition according to the present invention is applied to a ball-point pen having a ball-point pen tip consisting of a tip body provided with a metal ball seat and a metal ball, a phosphoric acid ester-based surfactant is used as a lubricant. is preferably used.
Phosphate ester-based surfactants have the property that the phosphate group is likely to adsorb to metals. The surfactant adheres to the ball and the ball receiving seat, forming a lubricating layer composed of a phosphoric acid ester surfactant on the surface of the ball and the ball receiving seat, thereby improving the lubricity between the ball and the ball receiving seat. It can be improved to rotate the ball smoothly. In addition, it is possible to suppress wear of the ball receiving seat and improve writing feeling such as writing feeling.

In addition, the ink composition according to the present invention can also be blended with a non-thermochromic colorant such as a general dye or pigment, and exhibits color change behavior from colored (1) to colored (2).

The method for producing the ink composition according to the present invention is not particularly limited, and any conventionally known method can be used. Specifically, the ink composition is obtained by stirring the mixture containing the above components with various stirrers such as propeller stirring, homodispers, and homomixers, or by dispersing with various dispersers such as bead mills. can manufacture things.

When the ink composition according to the present invention is used in a ball-point pen, the viscosity of the ink composition is determined by sedimentation or agglomeration of the microcapsule pigment when measured at a rotational speed of 1 rpm (shear rate of 3.84 sec ⁻¹ ) in an environment of 20°C. is preferably from 1 to 2000 mPa·s, more preferably from 3 to 1500 mPa·s, and still more preferably from 500 to 1000 mPa·s. In addition, when measured at a rotational speed of 100 rpm (shear rate of 384 sec ⁻¹ ) in an environment of 20° C., the viscosity is preferably 1 because the ink ejection property from the pen tip of the ballpoint pen can be improved. It is in the range of up to 200 mPa·s, more preferably 10 to 100 mPa·s, still more preferably 20 to 50 mPa·s. When the viscosity is within the above range, the dispersion stability of the microcapsule pigment and the free flowability of the ink composition in the mechanism of the ballpoint pen can be maintained at a high level.
The viscosity was measured using a rheometer "Discovery HR-2, cone plate (diameter 40 mm, angle 1°)" (trade name, manufactured by TA Instruments Japan Co., Ltd.) under an environment of 20°C. It can be measured at a rotation speed of 1 rpm (shear rate of 3.84 sec ^-1 ) or at a rotation speed of 100 rpm (shear rate of 384 sec ^-1 ).

When the ink composition according to the present invention is used for a ball-point pen, its surface tension is preferably in the range of 20-50 mN/m, more preferably 25-45 mN/m in an environment of 20°C. When the surface tension is within the above range, bleeding of writing lines and strike-through to the paper surface can be easily suppressed, and the wettability of the ink composition to the paper surface can be improved.
The surface tension was measured using a surface tension measuring instrument "DY-300" (trade name, manufactured by Kyowa Interface Science Co., Ltd.), placing the ink composition in an environment of 20 ° C., and measuring a vertical flat plate using a platinum plate. It can be measured by the method.

When the ink composition according to the present invention is used in ballpoint pens, the pH is preferably in the range of 3-10, more preferably 4-9. When the pH is within the above range, aggregation or sedimentation of the microcapsule pigment contained in the ink composition in a low temperature range can be suppressed.
The pH can be measured by placing the ink composition in an environment of 20° C. using a pH meter “IM-40S” (trade name, manufactured by Toa DKK Co., Ltd.).

When the ink composition according to the present invention is used for a marking pen, its viscosity is preferably 1 to 20 mPa·s, more preferably 1 to 10 mPa·s, when measured at a rotation speed of 30 rpm in an environment of 20°C. s, more preferably in the range of 1 to 5 mPa·s. When the viscosity is within the above range, the fluidity of the ink composition and the dispersion stability of the microcapsule pigment can be improved.
The viscosity was measured by placing the ink composition in an environment of 20°C using a BL-type rotational viscometer "TVB-M-type viscometer (L-type rotor)" (trade name, manufactured by Toki Sangyo Co., Ltd.). can be measured.

When the ink composition according to the present invention is used for a marking pen, its surface tension is preferably 25 to 50 mN/m, more preferably 25 to 45 mN, still more preferably 35 to 45 mN/m in an environment of 20°C. Range. When the surface tension is within the above range, bleeding of writing lines and strike-through to the paper surface can be easily suppressed, and the wettability of the ink composition to the paper surface can be improved.

The surface tension was measured using a surface tension measuring instrument "DY-300" (trade name, manufactured by Kyowa Interface Science Co., Ltd.), placing the ink composition in an environment of 20 ° C., and a vertical plate method using a glass plate. can be measured by

When the ink composition according to the present invention is used in a marking pen, its pH is preferably in the range of 3-8, more preferably 4-7, even more preferably 5-6. When the pH is within the above range, aggregation or sedimentation of the microcapsule pigment contained in the ink composition in a low temperature range can be suppressed.
The pH can be measured by placing the ink composition in an environment of 20° C. using a pH meter “IM-40S” (trade name, manufactured by Toa DKK Co., Ltd.).

When the ink composition according to the present invention is used in a ballpoint pen, the structure and shape of the ballpoint pen itself are not particularly limited. Used.

A ball-point pen tip consists of a tip body and a ball provided at the front end of the tip body. A tip made of a metal material, a tip made of a ball holding part formed by cutting with a drill or the like holding a ball, a resin made inside a metal or plastic tip body Examples include a tip provided with a ball receiving seat, or a tip in which a ball held by the tip is urged forward by a spring body.

The material of the tip body and the ball is not particularly limited, and examples thereof include cemented carbide (carbide), stainless steel, ruby, ceramics, resin, rubber, and the like. Furthermore, the ball can be subjected to surface treatment such as DLC coating.
The diameter of the ball is generally 0.2 to 3 mm, preferably 0.2 to 2 mm, more preferably 0.2 to 1.5 mm, still more preferably 0.2 to 1 mm, particularly preferably 0.2 to 0.5 mm. are applicable.

In general, microcapsules contained in microcapsule pigments have a larger average particle size than general-purpose pigment particles. The ink discharge from the tip is likely to be impaired, and writing defects such as blurring and line skipping may occur, and handwriting density may be impaired. However, the ink composition according to the present invention in which the average particle size of the microcapsules contained in the microcapsule pigment is in the range of 0.3 to 2 μm is used as a ball having a small diameter, particularly a ball having a diameter of 0.2 to 0.5 mm. When stored in a ballpoint pen provided at the writing tip, the ink ejection property from the pen tip is further improved, so that writing defects can be suppressed and a ballpoint pen that can form clear and high-density handwriting can be obtained. Therefore, it is preferable.

As an ink filling mechanism, for example, an ink container that can be directly filled with an ink composition can be exemplified.
As the ink container, for example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, or nylon, or a metal tubular body is used.
A ballpoint pen refill (hereinafter sometimes referred to as a "refill") is formed by connecting a ballpoint pen tip to an ink container directly or via a connecting member and directly filling the ink container with an ink composition. be able to. A ball-point pen can be formed by housing this refill in the barrel.

An ink backflow preventer is filled at the trailing end of the ink composition filled in the ink containing body. Ink backflow preventers include liquid or solid plugs.

The liquid plug consists of a non-volatile liquid and/or a sparingly volatile liquid, such as petroleum jelly, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefins, oligomers or co-oligomers of α-olefins, dimethyl Examples include silicone oil, methylphenyl silicone oil, amino-modified silicone oil, polyether-modified silicone oil, and fatty acid-modified silicone oil.

The nonvolatile liquid and/or the hardly volatile liquid can be used singly or in combination of two or more.

It is preferable to add a thickening agent to the non-volatile liquid and/or the low-volatility liquid to thicken it to a suitable viscosity.

Examples of thickening agents include silica whose surface is hydrophobically treated, fine particle silica whose surface is methylated, aluminum silicate, swelling mica, clay-based thickeners such as bentonite and montmorillonite, which are hydrophobically treated, and magnesium stearate. , fatty acid metal soaps such as calcium stearate, aluminum stearate, and zinc stearate; tribenzylidene sorbitol, fatty acid amides, amide-modified polyethylene waxes; .

Examples of solid plugs include solid plugs made of polyethylene, polypropylene, and polymethylpentene.
As an ink backflow preventer, the liquid plug and the solid plug can be used in combination.

Further, a ball-point pen having a ball-point pen tip and an ink filling mechanism is provided by using the barrel itself as an ink filling mechanism, directly filling the ink composition into the barrel, and attaching the ball-point pen tip to the front end of the barrel. can also be formed.

When the ink composition filled in the ink filling mechanism has a low viscosity, the ballpoint pen provided with the ballpoint pen tip and the ink filling mechanism further supplies the ink composition filled in the ink filling mechanism to the pen tip. ink supply mechanism.

The ink supply mechanism is not particularly limited, and includes, for example: (1) a mechanism having an ink guide wick made of a fiber bundle or the like as an ink flow rate regulator, interposed therebetween to supply the ink composition to the nib; (2) A mechanism having a comb groove-shaped ink flow rate regulator through which the ink composition is supplied to the pen tip; A slit-shaped ink guide groove that extends through the body in the axial direction and a ventilation groove wider than the groove are provided, and an ink guide core is arranged in the axial center for guiding the ink composition from the ink filling mechanism to the nib. and a mechanism for supplying the ink composition to the pen tip through the pen core.

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

When the ball-point pen is provided with the above-described ink supply mechanism, the ink filling mechanism may be an ink storage body capable of being filled with an ink composition, in addition to the above-described ink container or barrel.

The ink occluding body is a fiber bundle formed by bundling crimped fibers in the longitudinal direction. adjusted and configured.

Further, the ink containing body contains an ink occluding body impregnated with the ink composition, and an ink supplying mechanism is provided at the front end of the ink containing body so as to be connected to the ink occluding body, and is connected to the ink supplying mechanism. By connecting the ballpoint pen tip to the ink supply mechanism either directly or via a connecting member, it is possible to form a ballpoint pen refill that includes the ballpoint pen tip, the ink filling mechanism, and the ink supply mechanism. Alternatively, an ink storage body impregnated with an ink composition is housed in the ink storage body, and an ink supply mechanism is provided inside the ink storage body so as to be connected to the ink storage body, and is connected to the ink supply mechanism. A ballpoint pen refill can also be formed by connecting the ballpoint pen tip directly or via a connecting member to the ink container.

Specifically, the configuration of the ball-point pen containing the ink composition according to the present invention is as follows: (1) An ink containing body filled with the ink composition is provided in the barrel, and the ink containing body is provided directly or with a connecting member. (2) a comb groove-like ink flow controller in which the ink composition is directly filled in the shaft cylinder; (3) A ballpoint pen having a mechanism for supplying an ink composition to the nib by interposing an ink guide core made of a fiber bundle or the like as an ink flow rate regulator; (4) A ballpoint pen having a mechanism for supplying an ink composition to the nib through a core; A ball-point pen or the like having a mechanism for supplying an ink composition to the nib by interposing an ink guide core as an ink flow rate regulator can be exemplified.

When the ink composition according to the present invention is used in a marking pen, the structure and shape of the marking pen itself are not particularly limited. Alternatively, it is used by filling a marking pen.

As a marking pen tip, for example, a porous material with continuous pores selected from the range of about 30 to 70% in porosity, such as resin-processed fiber, fusion-bonded body of heat-fusible fiber, felt body, etc. A member, or a synthetic resin extruded body having a plurality of ink outlet holes extending in the axial direction can be exemplified, and one end can be processed into a shape according to the purpose, such as a cannonball shape, a rectangular shape, a chisel shape, etc., for practical use. be done.

As an ink filling mechanism, for example, an ink occlusion body that can be filled with an ink composition can be exemplified.
The ink occluding body is a bundle of crimped fibers bundled in the longitudinal direction, and is incorporated in a covering such as a plastic cylinder or a film, and the porosity is adjusted to a range of approximately 40 to 90%. Configured.

An ink occluding body impregnated with an ink composition is accommodated in a barrel, and a marking pen tip is connected to the barrel directly or via a connecting member so as to be connected to the ink occluding body. can be formed.

Further, by housing an ink occluding body impregnated with an ink composition in the ink containing body and connecting the marking pen tip to the ink containing body directly or via a connecting member so as to be connected to the ink occluding body, Marking pen refills (hereinafter sometimes referred to as "refills") can be formed. A marking pen can be formed by housing this refill in a barrel.

As the ink container, for example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, or nylon, or a metal tubular body is used.

A marking pen comprising a marking pen tip and an ink filling mechanism may further comprise an ink supply mechanism for supplying the pen tip with an ink composition filled in the ink filling mechanism.

The ink supply mechanism is not particularly limited, and includes, for example: (1) a mechanism having an ink guide wick made of a fiber bundle or the like as an ink flow rate regulator, interposed therebetween to supply the ink composition to the nib; (2) A mechanism having a comb groove-shaped ink flow rate regulator through which the ink composition is supplied to the pen tip; A slit-shaped ink guide groove that extends through the body in the axial direction and a ventilation groove wider than the groove are provided, and an ink guide core is arranged in the axial center for guiding the ink composition from the ink filling mechanism to the nib. and (4) a mechanism provided with an ink flow control body by a valve mechanism and supplying the ink composition to the pen tip by opening the valve.

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

As the valve mechanism, a general-purpose pumping type that is opened by pressing the tip can be used, and a spring pressure that can be opened by writing pressure is preferable.

When the marking pen is provided with an ink supply mechanism, the ink filling mechanism may be an ink containing body that can be directly filled with the ink composition, in addition to the above-described ink occluding body. Alternatively, the ink composition may be directly filled by using the barrel itself as an ink filling mechanism.

Further, the ink containing body contains an ink occluding body impregnated with the ink composition, and an ink supplying mechanism is provided at the front end of the ink containing body so as to be connected to the ink occluding body, and is connected to the ink supplying mechanism. A marking pen refill comprising a marking pen tip, an ink filling mechanism, and an ink supply mechanism can also be formed by connecting the marking pen tip to the ink supply mechanism either directly or via a connecting member. Alternatively, an ink storage body impregnated with ink is housed in the ink storage body, an ink supply mechanism is provided inside the ink storage body so as to be connected to the ink storage body, and marking is provided so as to be connected to the ink supply mechanism. A marking pen refill can also be formed by connecting the pen tip to the ink reservoir either directly or via a connecting member.

Specifically, the configuration of the marking pen containing the ink composition according to the present invention is as follows: (1) An ink occluding body composed of a bundle of fibers impregnated with the ink composition is contained in the shaft cylinder, and a capillary gap is formed. (2) a marking pen in which a marking pen tip made of a fiber processed body or a resin molded body is connected to a barrel directly or via a connecting member so that the ink occluding body and the tip are connected to each other; The marking pen is directly filled with the ink composition, and has a mechanism for supplying the ink composition to the nib by interposing a comb groove-like ink flow control body or an ink guide core made of a fiber bundle or the like as an ink flow control body. (3) A marking pen in which an ink composition is directly filled in a barrel and provided with a mechanism for supplying the ink composition to the nib through the pen core; (4) A valve that is opened by pressing the tip. (5) A marking pen comprising a tip and an ink container via a mechanism, and an ink composition directly filled in the ink container; A marking pen tip made of a fiber processed body or a resin molded body having an ink container containing an occluding body and having a capillary gap formed thereon is connected directly or via a connecting member so that the ink occluding body and the tip are connected. A marking pen or the like connected to the ink container can be exemplified.

In the case where the ballpoint pen or marking pen is directly filled with the ink composition, the ink container or barrel filled with the ink composition may be filled with the ink in order to facilitate the redispersion of the microcapsule pigment. It is preferable to incorporate a stirring body such as a stirring ball for stirring the composition. Examples of the shape of the stirrer include a spherical body and a rod-like body. The material of the stirrer is not particularly limited, and examples thereof include metals, ceramics, resins, and glass.

Furthermore, the above-mentioned writing implements such as ballpoint pens or marking pens can also be in the form of ink cartridges as a detachable structure. In this case, after the ink composition stored in the ink cartridge of the writing instrument has been used up, it can be used by replacing it with a new ink cartridge.

As the ink cartridge, one that is connected to the body of the writing instrument and serves as a barrel constituting the writing instrument, and one that covers and protects the barrel (rear barrel) after being connected to the body of the writing instrument is used. In the latter, in addition to using the ink cartridge alone, the writing instrument body and the ink cartridge are connected to the writing instrument before use, and the user of the writing instrument can use it by connecting the ink cartridge inside the barrel when using it. It can be any of those housed in the barrel unconnected to begin with.

Furthermore, the writing instrument having the above configuration is provided with a cap that is attached so as to cover the pen tip (writing tip) to make it a cap-type writing instrument. It is possible to prevent the part from being contaminated and damaged.

In addition, a ballpoint pen or marking pen in which a refill is stored in a barrel can be made into a retractable writing instrument by providing a retractable mechanism that allows the writing tip to retract and retract from the barrel. can be prevented from being contaminated or damaged.
Any retractable writing instrument can be used as long as it has a structure in which the writing tip is housed in the barrel with the writing tip exposed to the outside air, and the writing tip protrudes from the barrel opening by the operation of the retraction mechanism. .

For example, (1) an operating portion (clip) movable in the front-rear direction is protruded radially outward from the rear side wall of the barrel, and the operating portion is slid forward to open the front end of the barrel. (2) A rear end knock that causes the writing tip to appear and retract from the front end opening of the barrel by pushing forward an operation part provided at the rear end of the barrel. (3) a side-knock type retracting mechanism for retracting the writing tip from the front end opening of the barrel by pressing an operating portion protruding from the outer surface of the side wall of the barrel radially inward; A rotating retractable mechanism or the like that retracts and retracts the writing tip from the front end opening of the barrel can be exemplified by rotating the operating portion at the rear portion of the cylinder.

Furthermore, the form of the ball-point pen or marking pen is not limited to the above-described configuration, and in addition to attaching tips of different forms, attaching tips that lead out ink compositions of different color tones, and using tips of different forms. A composite writing instrument (a double-headed type, a nib extension type, etc.) may be used in which the color tone of the ink composition drawn out from each tip is different while being attached.
In addition, it is also possible to provide a composite type retractable writing instrument in which a plurality of refills are accommodated in the barrel, and the writing tip of any one of the refills is retracted from the opening of the barrel by the actuation of the retraction mechanism.

The average particle size of the microcapsules contained in the ink composition according to the present invention is 0.1 to 3.0 μm, and the range of the average particle size is preferably adjusted according to the type of writing instrument to which the ink composition is applied. . For example, the ink filling mechanism is configured to directly fill the ink composition, and the ink supply mechanism has a slit-shaped configuration in which a large number of discs are arranged in parallel with a comb groove-like interval, and the discs are axially traversed. A writing utensil equipped with a pen core having an ink guide groove and a vent groove wider than the groove, and an ink guide core for guiding the ink composition from the ink filling mechanism to the pen tip at the center of the axis ( In the ink composition contained in a direct liquid writing instrument, the average particle size of the microcapsules is preferably in the range of 0.3 to 2.0 μm, more preferably in the range of 0.3 to 1.5 μm. More preferably, it is in the range of 0.3 to 1.0 μm.

An ink composition containing microcapsules having an average particle size within the above range has excellent dispersion stability in the ink composition even when the ink composition has a low viscosity, and aggregation or sedimentation of the microcapsule pigment is suppressed. Therefore, the ink discharge from the pen tip is less likely to be hindered, and writing defects such as blurring and line skipping are less likely to occur. In addition, in the writing instrument having the above-described structure, the low-viscosity ink composition is directly filled into the ink filling mechanism, so that a large amount of ink can be discharged and clear handwriting can be formed. Since the effect of appropriately adjusting the ink flow rate from the mechanism is exhibited, the ink composition can be more stably ejected from the pen tip.

Therefore, by applying the ink composition according to the present invention in which the average particle size of the microcapsules is within the above range to a direct liquid writing instrument, the ink composition can be stably discharged from the pen tip, resulting in a clear and dense handwriting. It is preferably used because high handwriting can be formed.

Furthermore, the ink composition according to the present invention is contained in a ballpoint pen (direct liquid ballpoint pen), which is a ballpoint tip with a ball having a diameter of 0.2 to 0.5 mm, in a direct liquid writing instrument. is more preferable.

Since the diameter of the ball provided at the pen tip of the direct liquid ballpoint pen is small, especially when applying an ink composition containing microcapsule pigments having a larger average particle diameter than general-purpose pigments, the ink ejection from the pen tip is poor. However, by applying an ink composition in which the microcapsules have an average particle size of 0.3 to 2.0 μm, the ink ejection property from the pen tip is improved, and blurring, line skipping, etc. Therefore, it is possible to obtain a ball-point pen capable of forming a clear handwriting with high handwriting density, which is more preferably used.

It is possible to form a handwriting by writing on a writing surface using a writing instrument containing the ink composition of the present invention, and the handwriting can be formed by rubbing with a finger or by changing the temperature with a heating or cooling device. can be discolored.

As a heating tool, a friction member and friction body that can be heated by frictional heat, an electric heating discoloring tool equipped with a resistance heating element such as a PTC element, a heating discoloring tool filled with a medium such as hot water, steam, laser light, etc. Application of a heat discoloring tool, a hair dryer, and the like can be mentioned, but a friction member and a friction body are preferable because they can be discolored by a simple method.

Examples of the cooling device include an electrically-cold heat discoloring device using a Peltier element, a cold heat discoloring device filled with a refrigerant such as cold water or ice chips, a cooling agent, a refrigerator or a freezer, and the like.

As the friction member and the friction body, elastic bodies such as elastomers and plastic foams, which are rich in elasticity and can generate frictional heat by generating moderate friction when rubbed, are preferable. Metal, fabric, etc. can also be used.

A general eraser that is used to erase handwriting with a pencil may be used to rub the handwriting, but since eraser scum is generated during rubbing, the above friction member and Friction bodies are preferably used.

Examples of materials for the friction member and friction body include silicone resin and SEBS resin (styrene-ethylene-butadiene-styrene block copolymer). The SEBS resin is more preferably used because the silicone resin tends to adhere to areas erased by rubbing, and the handwriting tends to be repelled when repeatedly written.

The above-mentioned friction member or friction body may be a member of any shape separate from the writing instrument, but by providing it in the writing instrument, the portability can be improved. A writing instrument set can also be obtained by combining a writing instrument with a friction member or friction body of arbitrary shape that is separate from the writing instrument.

When the writing instrument is a cap-type writing instrument, the place where the friction member or the friction body is provided is not particularly limited. When provided, the clip itself can be formed of a friction member, or a friction member or friction body can be provided at the cap tip (top) or barrel rear end (portion where the writing tip is not provided).

When the writing instrument is a retractable writing instrument, the location where the friction member or the friction body is provided is not particularly limited. A friction member or a friction body can be provided near the opening of the barrel, the rear end of the barrel (the portion where the writing tip is not provided), or the knock portion.

Examples are shown below. In addition, unless otherwise specified, "parts" in the examples indicate "mass parts".

・Example 1
(Preparation of reversible thermochromic microcapsule pigment)
(a) 4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluorane as component, (b) 8 parts of 2,2-bis(4-hydroxyphenyl)hexafluoropropane as component, A reversible thermochromic composition was prepared by mixing 50 parts of 4-benzyloxyphenylethyl caprate as the component (c). This composition was added to a mixed solution comprising 45 parts of an aromatic isocyanate prepolymer as a coating material and 40 parts of a co-solvent. This mixed solution was emulsified and dispersed in a 10% aqueous solution of polyvinyl alcohol, and after stirring with a homomixer at a stirring speed of 10,000 rpm while heating, 2.5 parts of a water-soluble modified aliphatic amine was added and further stirred. was continued to prepare a microcapsule dispersion. A reversible thermochromic microcapsule pigment was obtained by filtering the above microcapsule dispersion with a filter press.

The resulting reversible thermochromic microcapsule pigment has _a complete coloring temperature t1 of −20° C. and a complete decoloring temperature _t4 of 60° C. From the colored state, it can be reversibly changed from black to colorless by heating. changed to

The average particle size (X) of the microcapsules contained in the reversible thermochromic microcapsule pigment was measured using a laser diffraction/scattering particle size distribution analyzer (LA-300 (trade name, Co., Ltd.) calibrated by an image analysis method. HORIBA, Ltd.)) was used for measurement. The obtained volume-based average particle size (X) was 0.75 μm. The content of microcapsules having a particle diameter of 8 μm or more (large particle content) was 0% by volume based on the total volume of microcapsules in the microcapsule pigment.

The average cross-sectional thickness (Y) of the microcapsules contained in the reversible thermochromic microcapsule pigment is obtained by freezing an aqueous dispersion of the microcapsule pigment in which the reversible thermochromic composition is in a colored state, and deforming the microcapsule pigment. A 50 μm-thick thin section sample was prepared by microtome, and the observed image was analyzed and measured by a transmission electron microscope (HT7700 (trade name, manufactured by Hitachi High-Tech Co., Ltd.)). There were 150 microcapsules in the field of view of the observation image. By image analysis, the cross-sectional film thickness of all microcapsules was calculated, and the average cross-sectional film thickness (Y) obtained from the average value was 0.08 μm.

(Preparation of reversible thermochromic ballpoint pen)
25 parts of the microcapsule pigment of Example 1 (previously cooled to −20° C. or lower to develop a black color), 0.2 parts of a shear thinning agent (xanthan gum), 10 parts of urea, and 10 parts of glycerin and 0.5 parts of a nonionic permeability imparting agent (manufactured by San Nopco Co., Ltd., product name: Nopco SW-WET-366), and a modified silicone antifoaming agent (manufactured by San Nopco Co., Ltd., product name: Nopco 8034). 1 part, 0.5 parts of a phosphate ester surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Plysurf AL), 0.5 parts of a pH adjuster (triethanolamine), and an antifungal agent [Lonza Japan Co., Ltd., product name: Proxel XL-2 (S)] 0.2 parts and 53 parts of water were mixed to prepare a reversible thermochromic ink composition for writing instruments.

After the obtained ink composition was suction-filled into an ink storage tube made of a polypropylene pipe, it was connected via a resin holder to a ball-point pen tip having a cemented carbide ball with a diameter of 0.5 mm held at the tip. . Next, from the rear end of the ink storage tube, a viscoelastic ink backflow preventer (liquid plug) mainly composed of polybutene is filled, and the tail plug is fitted to the rear of the pipe, and degassed by centrifugal separation. and obtained a ballpoint pen refill.

Next, the above refill was incorporated into the barrel to produce a retractable ballpoint pen.
The above-mentioned ballpoint pen is housed in the barrel with the tip provided on the ballpoint pen refill exposed to the outside air, and is operated by a clip-shaped retracting mechanism (slide mechanism) provided on the rear side wall of the barrel. The tip protrudes from the front end opening of the barrel. SEBS resin is attached as a friction member to the rear end of the barrel.

- Examples 2 to 28, and Comparative Examples 1 and 2
(Preparation of reversible thermochromic microcapsule pigment)
The addition amount and stirring speed of the coating material of Example 1 were changed as shown in Table 1 to obtain reversible thermochromic microcapsule pigments used in writing instruments of Examples 2 to 28 and Comparative Examples 1 and 2. .

(Preparation of reversible thermochromic ballpoint pen)
Using an ink composition prepared in the same manner as the ink composition of Example 1, reversible thermochromic ballpoint pens of Examples 2 to 28 and Comparative Examples 1 and 2 having the same structure as in Example 1 were produced. bottom.

(initial written test)
Using the ballpoint pens of Examples 1 to 28 and Comparative Examples 1 and 2, in a room temperature (20 ° C.) environment, parallel to the short direction of A4 size test paper (portrait), 12 per line. Circles (15 mm long and 8 mm short) on the ellipse were handwritten in a spiral so that the circles were in contact with each other, and 3 consecutive lines were written. Writing paper A conforming to old JIS P3201 was used as the test paper.

(Evaluation of handwriting density)
The handwriting obtained in the initial writing test was visually confirmed, and the handwriting density was evaluated according to the following criteria. The evaluation results are shown in Table 1 below.
A: The handwriting density is very high and clear.
B: The handwriting density is high.
C: Slightly low handwriting density, but sufficiently visible.
D: The handwriting density is somewhat low, but there is no practical problem.
E: The handwriting density is light and the visibility is low. There are practical problems.

(Evaluation of ink jettability)
The handwriting obtained in the initial writing test was visually confirmed, and the ink ejection property was evaluated according to the following criteria. The evaluation results are shown in Table 1 below.
A: There is no blurring or line skipping in the handwriting.
B: Slight blurring and line skipping are observed in the handwriting, but there is no practical problem.
C: There are many blurs and line skips in the handwriting. There are practical problems.

(storage over time)
Each ball-point pen subjected to the initial writing test was allowed to stand in a constant temperature bath set at 50° C. for 60 days with the writing tip facing downward, and after 60 days had passed, it was removed from the constant temperature bath.

(Evaluation of dispersion stability)
The state of the ink contained in the refill in each ball-point pen that had been stored over time was visually confirmed, and the dispersion stability was evaluated according to the following criteria. The evaluation results are shown in Table 1 below.
A: No sedimentation of microcapsule pigment was observed in the ink in the refill, and the appearance was the same as the initial stage.
B: Slight separation was observed in the ink in the refill due to agglomeration and sedimentation of the microcapsule pigment, but there is no practical problem.
C: Separation due to aggregation and settling of the microcapsule pigment was observed in the ink in the refill. There are practical problems.

(Evaluation of durability of microcapsule coating)
Each ballpoint pen that has been stored over time as described above is placed in a room temperature (20 ° C) environment in a direction parallel to the short side of an A4 size test paper (portrait), 12 elliptical circles per line ( 15 mm in major diameter and 8 mm in minor diameter) was handwritten in a spiral so that the circles were in contact with each other in three consecutive lines. Writing paper A conforming to old JIS P3201 was used as the test paper.

The resulting handwriting was visually confirmed, and the film durability of the microcapsule pigment was evaluated according to the following criteria from the difference between the handwriting density in the initial writing test and the handwriting density of each ballpoint pen after storage over time. The evaluation results are shown in Table 1 below.
A: The handwriting density does not change at all compared to the handwriting obtained in the initial writing test.
B: The handwriting density is almost unchanged compared to the handwriting obtained in the initial writing test.
C: The handwriting density is slightly lighter than the handwriting obtained in the initial writing test.
D: The handwriting density is somewhat lighter than the handwriting obtained in the initial writing test, but there is no practical problem.
E: The handwriting density is significantly lighter than the handwriting obtained in the initial writing test. There are practical problems.

Coating material addition amount and stirring speed when preparing reversible thermochromic microcapsule pigments obtained in Examples 1 to 28 and Comparative Examples 1 and 2, microcapsules contained in microcapsule pigment (ink composition) Average particle diameter (X), average cross-sectional film thickness (Y), Y/X, and large particle content of, as well as handwriting density evaluation, ink ejection property evaluation, dispersion stability evaluation, and film durability evaluation results are shown in Table 1 below.

Application example 1
(Preparation of reversible thermochromic ballpoint pen)
25 parts of the reversible thermochromic microcapsule pigment of Example 5 (previously cooled to -20° C. or less to develop a black color), 0.2 parts of a shear thinning agent (xanthan gum), and 10 parts of urea , 10 parts of glycerin, 0.5 parts of a nonionic permeability imparting agent (manufactured by San Nopco Co., Ltd., product name: Nopco SW-WET-366), and a modified silicone antifoaming agent (manufactured by San Nopco Co., Ltd., product name: Nopco 8034) 0.1 part, 0.5 part of a phosphate ester surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Plysurf AL), and 0.5 part of a pH adjuster (triethanolamine) A reversible thermochromic ink composition for writing instruments was prepared by mixing 0.2 parts of an antifungal agent [manufactured by Lonza Japan Co., Ltd., product name: Proxel XL-2 (S)] and 53 parts of water.

After the above ink composition was filled in an ink storage tube made of a polypropylene pipe by suction, it was connected via a resin holder to a ball-point pen tip holding a stainless steel ball with a diameter of 0.5 mm at its tip. Next, from the rear end of the ink storage tube, a viscoelastic ink backflow preventer (liquid plug) mainly composed of polybutene is filled, and the tail plug is fitted to the rear part of the pipe. After the cylinder was assembled and the cap was fitted, degassing was performed by centrifugation to produce a ball-point pen. SEBS resin is attached as a friction member to the rear end of the rear barrel.

A black character (handwriting) was formed by writing on paper using the above ballpoint pen. It changed color to colorless, and this state could be maintained as long as it was not cooled to -20°C or below. When the paper surface was placed in a freezer and cooled to −20° C. or lower, the letters showed a discoloration behavior in which the letters turned black again, and this discoloration behavior could be reproduced repeatedly.

In addition, the reversible thermochromic microcapsule pigment used in the ball-point pen was excellent in dispersion stability and film durability, and the above-mentioned ball-point pen had good ink ejection properties, and the handwriting formed by the ball-point pen was clear. Met.

Application example 2
(Preparation of reversible thermochromic microcapsule pigment A)
4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluorane, 2-di-n-butylamino-8-di-n-pentylamino-4-methylspiro[5H-[1 ] Benzopyrano[2,3-d]pyrimidine-5,1′(3′H)-isobenzofuran]-3′-one was replaced with 1 part. A synthetic microcapsule pigment A was prepared.

The above-mentioned reversible thermochromic microcapsule pigment _A has a complete coloring temperature t1 of -20°C and a complete coloration temperature _t4 of 60°C. changed to

(Preparation of reversible thermochromic marking pen)
20 parts of the above microcapsule pigment A (preliminarily cooled to -20 ° C. or less to develop a pink color) was added to a polymer flocculant (hydroxyethyl cellulose) (manufactured by Dow Chemical Japan Co., Ltd., product name: CELLOSIZE EP-09). ) 0.4 parts, an acrylic polymer dispersant (manufactured by Nippon Lubrizol Co., Ltd., product name: Solsperse 43000) 0.4 parts, and a preservative (2-pyridinethiol 1-oxide sodium) (Lonza Japan Co., Ltd. 0.2 parts of antiseptic (3-iodo-2-propynyl N-butyl carbamate) (manufactured by Lonza Japan Co., Ltd., product name: Glycasil 2000) and 0.2 parts of glycerin 18. part, 0.2 part of an antifoaming agent, 1 part of a pH adjuster (10% diluted phosphoric acid solution), 8 parts of a specific gravity adjuster (sodium polytungstate) (manufactured by SOMETU, product name: SPT), It was mixed in an aqueous vehicle consisting of 46.6 parts of water to prepare a reversible thermochromic ink composition for writing instruments.

An ink occluding body made of polyester sliver covered with a synthetic resin film is impregnated with the above ink composition, housed in a barrel made of polypropylene resin, and a plurality of inks extending in the axial direction are attached to the tip of the barrel via a holder. A marking pen was manufactured by assembling resin-processed pen bodies (cannonball-shaped) made of extruded bodies of polyacetal resin having ink outlet holes in a connected state, and attaching caps. SEBS resin is mounted on the top of the cap as a friction member.

When a pink character (handwriting) was formed by writing on paper using the above marking pen, the handwriting was pink at room temperature (25 ° C.). The color disappeared and became colorless, and this state could be maintained unless cooled to -20°C or lower. When the paper surface was placed in a freezer and cooled to −20° C. or lower, the characters showed a discoloration behavior in which the characters turned pink again, and this discoloration behavior could be reproduced repeatedly.

In addition, the reversible thermochromic microcapsule pigment used in the marking pen was excellent in dispersion stability and coating durability. The handwriting was clear.

Application example 3
(Preparation of reversible thermochromic microcapsule pigment B)
4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluorane was replaced with 5 parts of 6-(N-ethyl-N-isopentylamino)-1,2-benzofluorane A reversible thermochromic microcapsule pigment B was prepared in the same formulation and method as in Example 16, except for the above.

The above reversible thermochromic microcapsule pigment B has _a complete coloring temperature t1 of -20°C and a complete decoloring temperature _t4 of 59°C. changed to

(Preparation of reversible thermochromic ballpoint pen)
25 parts of the microcapsule pigment B (previously cooled to −20° C. or less to develop a red color), 0.2 parts of a shear thinning agent (xanthan gum), 10 parts of urea, and 10 parts of glycerin , Nonionic penetration imparting agent (manufactured by San Nopco Co., Ltd., product name: Nopco SW-WET-366) 0.5 parts, modified silicone antifoaming agent (manufactured by San Nopco Co., Ltd., product name: Nopco 8034) 0.1 part, 0.5 part of phosphate ester surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: PLYSURF AL), 0.5 part of pH adjuster (triethanolamine), antifungal agent [ Proxel XL-2 (S) manufactured by Lonza Japan Co., Ltd.] and 53 parts of water were mixed to prepare a reversible thermochromic ink composition for writing instruments.

After the above ink composition was filled in an ink storage tube made of a polypropylene pipe by suction, it was connected via a resin holder to a ball-point pen tip having a cemented carbide ball with a diameter of 0.3 mm held at its tip. Next, from the rear end of the ink storage tube, a viscoelastic ink backflow preventer (liquid plug) mainly composed of polybutene is filled, and the tail plug is fitted to the rear of the pipe, and degassed by centrifugal separation. and obtained a ballpoint pen refill.
Next, the above refill was incorporated into the barrel to produce a retractable ballpoint pen.

The above-mentioned ballpoint pen is housed in the barrel with the tip provided on the ballpoint pen refill exposed to the outside air, and is operated by a clip-shaped retracting mechanism (slide mechanism) provided on the rear side wall of the barrel. The tip protrudes from the front end opening of the barrel. SEBS resin is attached as a friction member to the rear end of the barrel.

A red character (handwriting) was formed by writing on paper using the above ballpoint pen. It changed color to colorless, and this state could be maintained as long as it was not cooled to -20°C or below. When the paper surface was placed in a freezer and cooled to −20° C. or below, the characters showed a discoloration behavior that turned red again, and this discoloration behavior could be reproduced repeatedly.

In addition, the reversible thermochromic microcapsule pigment used in the ballpoint pen was excellent in dispersion stability and film durability of the coating. It was clear.

Application example 4
(Preparation of reversible thermochromic microcapsule pigment C)
4.5 parts of 2-(2-chloroanilino)-6-di-n-butylaminofluorane, 3′,6′-bis[3-phenyl(3-methylphenyl)amino]-spiro[isobenzofuran-1 (3H),9'-[9H]xanthene]-3-one was replaced with 2 parts, but reversible thermochromic microcapsule pigment C was prepared in the same formulation and method as in Example 19.

The reversible thermochromic microcapsule pigment C has a complete coloring temperature t ₁ of −20° C. and a complete decoloring temperature t ₄ of 60° C. From the colored state, it can be reversibly changed from blue to colorless by heating. changed to

(Preparation of reversible thermochromic marking pen)
23 parts of the above microcapsule pigment C (preliminarily cooled to -20 ° C. or less to develop a blue color) was added to a polymer flocculant (hydroxyethyl cellulose) (manufactured by Dow Chemical Japan Co., Ltd., product name: CELLOSIZE WP-09). ) 0.4 parts, an acrylic polymer dispersant (manufactured by Nippon Lubrizol Co., Ltd., product name: Solsperse 43000) 0.4 parts, and a preservative (2-pyridinethiol 1-oxide sodium) (Lonza Japan Co., Ltd. 0.2 parts of antiseptic (3-iodo-2-propynyl N-butyl carbamate) (manufactured by Lonza Japan Co., Ltd., product name: Glycasil 2000) and 0.2 parts of glycerin 30. part, 0.01 part of an antifoaming agent, 0.03 part of a pH adjuster (10% diluted phosphoric acid solution), and 45.76 parts of water in an aqueous vehicle. An ink composition was prepared.

The above-mentioned ink composition is impregnated into an ink occluding body made of polyester sliver covered with a synthetic resin film, placed in a barrel made of polypropylene resin, and a resin-processed pen body (chisel type) made of polyester fiber is placed at the tip of the barrel. , assembled in a connected state via a resin holder, attached a cap, and produced a marking pen. SEBS resin is attached as a friction member to the rear end of the barrel.

When a blue character (handwriting) was formed by writing on paper using the above marking pen, the handwriting was blue at room temperature (25 ° C.). The color disappeared and became colorless, and this state could be maintained unless cooled to -20°C or lower. When the paper surface was placed in a freezer and cooled to −20° C. or lower, the letters showed a discoloration behavior in which the letters turned blue again, and this discoloration behavior could be reproduced repeatedly.

In addition, the reversible thermochromic microcapsule pigment used in the marking pen was excellent in dispersion stability and coating durability. The handwriting was clear.

t ₁ complete color development temperature t ₂ color development start temperature t ₃ color development start temperature t ₄ complete color development temperature T ₁ complete color development temperature T ₂ color development start temperature T ₃ color development start temperature T ₄ complete color development temperature ΔH hysteresis width

Claims (11)

(b) an electron-donating color-forming organic compound,
(b) an electron-accepting compound, and (c) a reaction medium that reversibly causes an electron transfer reaction between components (a) and (b) in a specific temperature range, and a reversible thermochromic composition is applied as a coating. a reversible thermochromic microcapsule pigment comprising encapsulated microcapsules;
A reversible thermochromic ink composition for a writing instrument comprising a vehicle,
The volume-based average particle diameter (X) of the microcapsules is 0.1 to 3.0 μm, and
A cross section of the frozen microcapsule pigment was observed with a transmission electron microscope, and the following formula was obtained for all capsules within the observation field:
Cut cross-section film thickness = (cross-section outer diameter - cross-section inner diameter) / 2
(In the formula, the cross-sectional outer circumference diameter and the cross-sectional inner circumference diameter are the area of the area surrounded by the outer circumference of the film cross section and the area of the area surrounded by the inner circumference of the film cross section for one microcapsule. (calculated from
When the average cross-sectional thickness is obtained by obtaining the cross-sectional thickness obtained by the average cross-sectional thickness of the microcapsules, the average cross-sectional thickness (Y) of the microcapsules is 0.02 to 0.7 μm.
A thermochromic ink composition for writing instruments. The ink composition according to claim 1, wherein the average particle size (X) and the average cross-sectional thickness (Y) satisfy the following formula (1).
Y/X<0.3 (1) 3. The ink composition according to claim 1, wherein the average particle size (X) is 0.3 to 2.0 μm. The ink composition according to any one of claims 1 to 3, wherein the content of microcapsules having a particle diameter of 8 µm or more is 1% by volume or less based on the total volume of the microcapsules in the microcapsule pigment. . The ink composition according to any one of claims 1 to 4, wherein the reversible thermochromic microcapsule pigment has a blending ratio of 5 to 40 mass% based on the total mass of the ink composition. An ink composition according to any one of claims 1 to 5, wherein said vehicle is an aqueous vehicle. A writing instrument containing the reversible thermochromic ink composition for a writing instrument according to any one of claims 1 to 6. 8. The writing instrument according to claim 7, which is a ballpoint pen. 9. The ball-point pen according to claim 8, comprising a ball with a diameter of 0.2 to 0.5 mm at the writing tip. The writing instrument according to claim 7, which is a marking pen The writing instrument according to any one of claims 7 to 10, further comprising a friction member capable of discoloring handwriting formed by said writing instrument with frictional heat.

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