JP7532181B2 - Reversible thermochromic water-based ink composition and ballpoint pen - Google Patents

Description

The present invention relates to a reversible thermochromic water-based ink composition and a ballpoint pen.

A metallic luster reversibly thermochromic ink composition for writing instruments is known that contains a reversibly thermochromic pigment, a transparent metallic luster pigment, water, and a water-soluble organic solvent, and is said to provide handwriting with metallic luster and color change, and to produce highly decorative handwriting (see, for example, Patent Document 1).

JP 2004-244489 A

Although the brilliance of the transparent metallic luster pigment contained in the ink composition described in Patent Document 1 stands out on black paper, the brilliance of handwriting formed on a medium with high brightness, such as white paper, may be insufficient.
Furthermore, if the particle size of the transparent metallic luster pigment is increased or the amount of the transparent metallic luster pigment added is increased in order to enhance the brilliance of the handwriting, settling of the transparent luster pigment may occur during storage, resulting in unevenness in the color and brilliance of the handwriting.
An object of one aspect of the present invention is to provide an ink composition that is capable of forming thermochromic handwriting that exhibits excellent glitter even on a medium with high brightness.

The reversible thermochromic aqueous ink composition comprises a reversible thermochromic microcapsule pigment encapsulating a reversible thermochromic composition comprising an electron-donating color-forming organic compound, an electron-accepting compound, and a reaction medium that determines the temperature at which the color-forming reaction between the electron-donating organic compound and the electron-accepting compound occurs, a luster pigment, water, and a thickener, and has a viscosity measured at 20°C of 7000 to 25000 mPa·s at 0.1 sec ^- 1 and 17 to 30 mPa·s at 1000 sec ^-1 .

The ink composition may be required to have a shear thinning index of 0.2 to 0.35. The ink composition may be required to have a reversible thermochromic microencapsulated pigment content of 3 to 20 mass %, a glittering pigment content of 0.1 to 15 mass %, and a thickener content of 0.17 to 0.55 mass %, based on the total mass of the ink composition.

The ballpoint pen is required to contain an ink composition. The ballpoint pen has a ballpoint pen tip having an ink flow hole provided in the center of a bottom wall of a ball holding chamber and ink flow grooves extending radially from the ink flow hole, a ball is placed on the bottom wall, and a tip end of the tip is crimped inward so that a part of the ball protrudes from the tip end and is held rotatably, and the ink flow groove may be formed to have a groove width of 0.1 to 0.2 mm. The ballpoint pen may be required to have a projected area of the ink flow groove that opens outward in the radial direction of the ballpoint pen tip from the contact part formed on the bottom wall of the ball holding chamber between the ball and the bottom wall of the ball holding chamber when the ball of the ballpoint pen tip is placed on the bottom wall of the ball holding chamber, of 0.015 to 0.03 ^mm2 per opening.

One aspect of the present invention aims to provide an ink composition that can produce thermochromic marks with excellent brilliance even on a medium with high brightness.

FIG. 2 is an explanatory diagram showing the color change behavior of a microcapsule pigment encapsulating a reversible thermochromic composition. FIG. 2 is an explanatory diagram showing the color change behavior of a microcapsule pigment encapsulating a reversible thermochromic composition having color memory properties. FIG. 1 is an explanatory diagram showing a retractable ballpoint pen that accommodates a ballpoint pen refill. FIG. 2 is a vertical cross-sectional view of a ballpoint pen tip. 5 is a cross-sectional view of the ballpoint pen tip shown in FIG. 4 along line AA.

In this specification, when the composition contains multiple substances corresponding to each component, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. Hereinafter, the embodiments of the present invention will be described in detail. However, the embodiments shown below are merely examples of ink compositions, etc., for embodying the technical concept of the present invention, and the present invention is not limited to the ink compositions, etc. shown below.

The reversible thermochromic water-based ink composition (hereinafter simply referred to as the "ink composition") contains a reversible thermochromic microcapsule pigment that encapsulates a reversible thermochromic composition consisting of an electron-donating color-forming organic compound, an electron-accepting compound, and a reaction medium that determines the temperature at which the color-forming reaction between the two occurs, a photoluminescent pigment, water, and a thickener.

(Photoluminescent pigment)
The luster pigment may be any pigment that can reflect light in a written form and exhibit luster, and examples of applicable luster pigments include surface-coated thin flake metal pigments, pigments in which a transparent base material is coated with a metal oxide, metal-coated glass flakes, metal powder pigments, and cholesteric liquid crystal type metallic luster pigments.
A plurality of types of luster pigments may be used in combination.

The surface-coated flaky metal pigment (hereinafter sometimes referred to as the first luster pigment) is formed by providing a resin layer on a metal foil. The resin layer is formed, for example, on both sides of the metal foil. The resin layer may also contain a colorant. The metal may be, for example, aluminum, and the surface may be mirror-finished. The average thickness of the first luster pigment is, for example, 0.5 μm or more and 5 μm or less, and preferably 1 μm or more and 3 μm or less. The average particle size of the first luster pigment is, for example, 5 μm or more and 200 μm or less, and preferably 10 μm or more and 60 μm or less. When the average particle size of the first luster pigment is within the above range, the first luster pigment is more effectively prevented from settling and agglomerating and being separated from the solvent, and it is possible to form a good handwriting with more suppressed unevenness in color and luster. In addition, the luster pigment is more easily removable when the handwriting is rubbed.

Here, the average thickness and average particle size of the first brilliant pigment are the arithmetic mean values of the maximum thickness and the maximum particle size of each particle measured by image analysis of images observed with a digital microscope in accordance with JIS Z 8827-1:2008. For image analysis, for example, image analysis type particle size distribution measurement software "Mac-View" manufactured by Mountech Co., Ltd. can be used.

The aspect ratio, which is the ratio of the average particle size to the average thickness of the first luster pigment, is, for example, 2 to 50, and preferably 10 to 30. When the aspect ratio is within the above range, handwriting with better luster can be formed. The true specific gravity of the first luster pigment is, for example, about 1.2 to 1.3, and has excellent dispersibility. The resin-coated flake-like metal pigment can be obtained, for example, by vacuum-depositing aluminum or the like on one side of a resin film such as polyester, coating with the desired color, and then cutting it into small pieces.

The first brilliant pigment is also called a glitter pigment, and specific examples thereof include LG neo SILVER #35, LG neo R-GOLD #35, LG neo B-GOLD #35, LG neo S-GOLD #35, LG neo SILVER #100, LG neo R-GOLD #100, LG neo B-GOLD #100, LG neo S-GOLD #100, LG neo RED #100, LG neo BLUE #100, LG neo GREEN #100, LG neo VIOLET #100, LG neo BLACK #100, and LG neo COPPER. #100, LZ neo PINK #100, LZ neo YELLOW #100, LZ neo R-GOLD #150, LZ neo B-GOLD #150, LZ neo S-GOLD #150, LZ neo RED #150, LZ neo BLUE #150, LZ neo GREEN #150, LZ neo VIOLET #150, LZ neo BLACK #150, LZ neo COPPER #150, LZ neo PINK #150, LZ neo YELLOW #150, LZ neo SILVER #200, LZ neo R-GOLD #200, LG neo B-GOLD #200, LG neo S-GOLD #200, LG neo RED #200, LG neo BLUE #200, LG neo GREEN #200, LG neo VIOLET #200, LG neo BLACK #200, LG neo COPPER #200, LG neo PINK #200, LG neo YELLOW #200, LG neo SILVER #325, LG neo R-GOLD #325, LG neo B-GOLD #325, LG neo S-GOLD #325, Elsie neo RED #325, Elsie n
eo BLUE #325, LG neo GREEN #325, LG neo VIOLET #325, LG neo BLACK #325, LG neo COPPER #325, LG neo PINK #325, LG neo YELLOW #325, LG neo SILVER #500, LG neo R-GOLD #500, LG neo B-GOLD #500, LG neo S-GOLD #500 (all manufactured by Oike Imaging Co., Ltd.), Diamond Peace LGGold No. 55, Diamond Peace DG Gold No. 55, Diamond Peace Green No. 55, Diamond Piece Blue No. 55, Diamond Piece Red No. 55, Diamond Piece Maroon No. 55, Diamond Piece Ocean Green No. 55, Diamond Piece Sky Blue No. 55, Diamond Piece Black No. 55, Diamond Piece Pink No. 55, Diamond Piece Violet No. 55, Diamond Piece Emerald No. 55, Diamond Piece Copper No. 55, Diamond Piece LG Gold H25, Diamond Piece DG Gold H25, Diamond Piece Green H25, Diamond Piece Blue H25, Diamond Piece Red H25, Diamond Piece Maroon H25, Diamond Piece Ocean Green H25, Diamond Piece Sky Blue H25, Diamond Piece Black H25, Diamond Piece Pink H25, Diamond Piece Violet H25, Diamond Piece Emerald H25, Diamond Piece Copper H25, Diamond Piece LG Gold H55, Diamond Piece DG Gold H55, Diamond Piece Green H55, Diamond Piece Blue
H55, Diamond Piece Red H55, Diamond Piece Maroon H55, Diamond Piece Ocean Green H55, Diamond Piece Sky Blue H55, Diamond Piece Black H55, Diamond Piece Pink H55, Diamond Piece Violet H55, Diamond Piece Emerald H55, Diamond Piece Copper H55, Diamond Piece LG Gold CO-40UC, Diamond Piece DG Gold CO-40UC, Diamond Piece Green CO-40UC, Diamond Piece Blue CO-40UC, Diamond Piece Red CO-40UC, Diamond Piece Pink CO-40UC, Diamond Piece Lavender CO-40UC (all manufactured by Diamond Industries Co., Ltd.). The first bright pigment may be used alone or in combination of two or more kinds.

A pigment in which a transparent substrate is coated with a metal oxide (hereinafter, sometimes referred to as a second luster pigment) can be applied to various substances for the substrate and metal oxide. Specifically, examples of the substrate having transparency include natural mica, synthetic mica such as KMg3(AlSi3O10)F2, flat glass, silica flakes, and flaky aluminum oxide. Examples of the metal oxide that coats the substrate include oxides of titanium, zirconium, chromium, vanadium, and iron, and preferably metal oxides mainly composed of titanium oxide. The second luster pigment exhibits a metallic luster of gold, silver, or metallic color depending on the coverage of the metal oxide that coats the surface of the substrate. The second luster pigment may be a layer of a metal oxide such as titanium oxide further coated with iron oxide or a non-thermochromic dye pigment.

The shape of the second luster pigment can be flat or scaly. The second luster pigment has an average thickness of, for example, 0.1 μm or more and 5 μm or less, and an average particle size of, for example, 0.2 μm or more and 200 μm or less, preferably 2 μm or more and 100 μm or less. When the average particle size of the second luster pigment is within the above range, the luster pigment is more effectively prevented from settling or agglomerating and being separated from the solvent, making it possible to form a good handwriting with less unevenness in color and luster. In addition, the luster pigment is more easily removed when the handwriting is rubbed.

The second luster pigment is also called a pearl pigment, and specific examples include the following. Pigments in which the surface of natural mica is coated with a metal oxide such as titanium oxide include Merck's product name "Iriodin" product numbers: 100 (particle size distribution 10 μm to 60 μm: Silver Pearl), 103 (particle size distribution 10 μm to 60 μm), 120 (particle size distribution 5 μm to 25 μm: Luster Satin), 123 (particle size distribution 5 μm to 25 μm), 201 (particle size distribution 5 μm to 25 μm: Rutile Fine Gold), 205 (particle size distribution 10 μm to 60 μm: Rutile Platinum Gold), 221 (particle size distribution 5 μm to 25 μm: Rutile Fine Blue), 225 (particle size distribution 10 μm to 60 μm: Rutile Blue Pearl), 231 (particle size distribution 5 μm to Examples include 25 μm: rutile fine red), 235 (particle size distribution 10 μm to 60 μm: rutile green pearl), Engelhard's product name "Lumina Colors" product number: Lumina Gold (particle size distribution 10 μm to 48 μm: gold), Lumina Red (particle size distribution 10 μm to 48 μm: metallic red), Lumina Red Blue (particle size distribution 10 μm to 48 μm: metallic blue), Lumina Aqua Blue (particle size distribution 10 μm to 48 μm: metallic blue), Lumina Green (particle size distribution 10 μm to 48 μm: metallic green), Lumina Turquoise (particle size distribution 10 μm to 48 μm: metallic green), etc.

As a pigment in which the surface of synthetic mica is coated with a metal oxide, the product name "Artimica" manufactured by Nihon Koken Kogyo Co., Ltd. is used. Product numbers are SB-100 (particle size distribution 5 μm to 30 μm: silver), SD-100 (particle size distribution 10 μm to 60 μm: silver), SE-100 (particle size distribution 15 μm to 100 μm: silver), SF-100 (particle size distribution 44 μm to 150 μm: silver), SH-100 (particle size distribution 150 μm: silver), and m to 600 μm: silver), YB-100 (particle size distribution 5 μm to 30 μm: gold), YD-100 (particle size distribution 10 μm to 60 μm: gold), YE-100 (particle size distribution 15 μm to 100 μm: gold), YF-100 (particle size distribution 44 μm to 150 μm: gold), RB-100 (particle size distribution 5 μm to 300 μm: metallic red), RD-100 (particle size distribution 10 μm to 60 μm m: metallic red), RE-100 (particle size distribution 15 μm to 100 μm: metallic red), RF-100 (particle size distribution 44 μm to 150 μm: metallic red), RBB-100 (particle size distribution 5 μm to 30 μm: metallic purple), RBD-100 (particle size distribution 10 μm to 60 μm: metallic purple), RBE-100 (particle size distribution 15 μm to 100 μm: metallic red) talic purple), RBF-100 (particle size distribution 44 μm to 150 μm: metallic purple), VB-100 (particle size distribution 5 μm to 30 μm: metallic violet), VD-100 (particle size distribution 10 μm to 60 μm: metallic violet), VE-100 (particle size distribution 15 μm to 100 μm: metallic violet), VF-100 (particle size distribution 44 μm to 150
Examples of the pigments include BB-100 (particle size distribution 5 μm to 30 μm: metallic blue), BD-100 (particle size distribution 10 μm to 60 μm: metallic blue), BE-100 (particle size distribution 15 μm to 100 μm: metallic blue), BF-100 (particle size distribution 44 μm to 150 μm: metallic blue), GB-100 (particle size distribution 5 μm to 30 μm: metallic green), GD-100 (particle size distribution 10 μm to 60 μm: metallic green), GE-100 (particle size distribution 15 μm to 100 μm: metallic green), and GF-100 (particle size distribution 44 μm to 150 μm: metallic green).

As a pigment in which the surface of flat glass pieces is coated with a metal oxide, scaly glass pieces coated with titanium oxide are manufactured by Nippon Sheet Glass Co., Ltd. under the trade name "Metashine" MC5090RS (average particle size 90 μm: silver), MC5090RY (average particle size 90 μm: gold), MC5090RR (average particle size 90 μm: red), MC5090RV (average particle size 90 μm: purple), MC5090RB (average particle size 90 μm: blue), MC5090RG (average particle size 90 μm: green), MC1080RS (average particle size 80 μm: silver), MC1080RY (average particle size 80 μm: gold), MC1080RR (average particle size 80 μm: red), MC1080RB (average particle size 80 μm: blue), MC1080R Examples include MC1040RS (average particle diameter 40 μm: silver), MC1040RY (average particle diameter 40 μm: gold), MC1040RR (average particle diameter 40 μm: red), MC1040RB (average particle diameter 40 μm: blue), MC1040RG (average particle diameter 40 μm: green), MC1020RS (average particle diameter 20 μm: silver), MC1020RY (average particle diameter 20 μm: gold), MC1020RR (average particle diameter 20 μm: red), MC1020RB (average particle diameter 20 μm: blue), MC1020RG (average particle diameter 20 μm: green), MC1080RSS1 (average particle diameter 80 μm: silver), MC1080RYS1 (average particle diameter 80 μm: gold), etc.

Examples of pigments in which the surface of silica flakes is coated with metal oxide include Merck's Colorstream product numbers F20-00WNT AutumnMystery (particle size distribution 5 μm to 40 μm) and T20-01WNT ViolaFantasy (particle size distribution 5 μm to 40 μm).

Examples of pigments in which the surface of flaky aluminum oxide is coated with a metal oxide include Merck's product name "Xiralic" product number: T50-10 (particle size distribution 10 μm to 30 μm: silver), T60-10WNT (particle size distribution 10 μm to 30 μm: silver), T60-20WNT (particle size distribution 10 μm to 30 μm: gold), T60-24WNT (particle size distribution 10 μm to 30 μm: metallic green), and T60-23WNT (particle size distribution 10 μm to 30 μm: metallic blue). The second luster pigment may be used alone or in combination of two or more types.

As the metal-coated glass flakes, glass flakes whose surfaces are coated with gold or silver can be used. Specific examples of metal-coated glass flakes include products manufactured by Nippon Sheet Glass Co., Ltd. under the trade name "Metashine" 2020PS (average particle size 25 μm: silver), 2040PS (average particle size 40 μm: silver), and 1030GP (average particle size 30 μm: gold), etc. Metal-coated glass flakes may be used alone or in combination of two or more types.

Metal powder pigments that can be used include aluminum, brass, stainless steel, tin, zinc, bronze, nickel, copper, gold, and silver, with aluminum being preferred because it has a low specific gravity and does not settle easily in the ink. Metal powder pigments can be used alone or in combination of two or more types.

Specific examples of cholesteric liquid crystal metallic luster pigments include the product name "Helicone HC" manufactured by Wacker Chemie, product numbers: Sapphire (SLM90020), Scarabeus (SLM90120), Jade (SLM90220), Maple (SLM90320), etc. Cholesteric liquid crystal metallic luster pigments have an average thickness of, for example, 3 μm or more and 15 μm or less, preferably 5 μm or more and 10 μm or less, and an average particle size of 1 μm or more and 100 μm or less. Cholesteric liquid crystal metallic luster pigments may be used alone or in combination of two or more types.

Considering the chemical stability in the ink and the suppression of aggregation and sedimentation of the glittering pigment in the ink, which makes it easier to form thermochromic handwriting with excellent glitter and reduced color unevenness, it is preferable to use a first glittering pigment and a second glittering pigment in combination as the glittering pigment. In addition, when the first glittering pigment and the second glittering pigment are used in combination as the glittering pigment, it also becomes easier to remove the glittering pigment when rubbing the handwriting.

The content of the photoluminescent pigment is preferably 0.1 to 15% by mass, more preferably 0.1 to 10% by mass. Particularly preferably 1 to 7% by mass. If the content is within the above range, the ink is chemically stable and the photoluminescent pigment is prevented from aggregating or settling in the ink, making it easy to form thermochromic handwriting with excellent photoluminescence and reduced color unevenness.

The ink composition contains at least one type of reversible thermochromic microencapsulated pigment. The reversible thermochromic microencapsulated pigment (hereinafter simply referred to as "microencapsulated pigment") contains a reversible thermochromic composition that is composed of an electron-donating color-forming organic compound, an electron-accepting compound, and a reaction medium that determines the temperature at which the color-forming reaction between the two occurs.

As the microencapsulated pigment, there can be used a microencapsulated pigment encapsulating a heat-discolorable reversible thermochromic composition having a relatively small hysteresis width (ΔH=1° C. to 7° C.), which is described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, etc. and which changes color around a certain temperature (discoloration point), exhibits a discolored state in a temperature range above the high-temperature discoloration point, and a colored state in a temperature range below the low-temperature discoloration point, and of the two states, only one specific state exists in the room temperature range, and the other state is maintained while the heat or cold required to manifest that state is applied, but returns to the state exhibited in the room temperature range when the application of the heat or cold is removed (see FIG. 1).

It is also possible to use a microcapsule pigment encapsulating a reversible thermochromic composition exhibiting large hysteresis characteristics, as described in JP-A-2006-137886, JP-A-2006-188660, JP-A-2008-45062, JP-A-2008-280523, etc. In other words, the shape of the curve plotting the change in color density due to temperature change follows a path that is significantly different when the temperature is increased from the lower side of the color change temperature range and when the temperature is decreased from the higher side of the color change temperature range, and the colored state in a low temperature range below the complete color development temperature (t1) or the decolored state in a high temperature range above the complete decolorization temperature (t4) can be a microcapsule pigment encapsulating a reversible thermochromic composition that has color memory in a specific temperature range [temperature range between t2 and t3 (substantially two-phase retention temperature range)] (see FIG. 2).

The hysteresis characteristics in the color density-temperature curve of a microcapsule pigment encapsulating a reversible thermochromic composition having color memory properties will be described below.
In Fig. 2, the vertical axis represents color density, and the horizontal axis represents temperature. The change in color density due to temperature change progresses along the arrow. Here, A is a point indicating the density at temperature t4 (hereinafter referred to as complete decolorization temperature) at which the completely decolorized state is reached, B is a point indicating the density at temperature t3 (hereinafter referred to as decolorization onset temperature) at which decolorization starts, C is a point indicating the density at temperature t2 (hereinafter referred to as color development onset temperature) at which color development starts, and D is a point indicating the density at temperature t1 (hereinafter referred to as complete color development temperature) at which the completely colored state is reached.
The discoloration temperature range is the temperature range between t1 and t4, and the temperature range between t2 and t3, which is a range in which both the colored state and the decolored state can coexist and in which the difference in color density is large, is the substantial discoloration temperature range.
The length of the line segment EF is a measure of the contrast of the discoloration, and the length of the line segment HG passing through the midpoint of the line segment EF is a temperature range indicating the degree of hysteresis (hereinafter referred to as hysteresis range ΔH). If this ΔH value is small, only one specific state of both the states before and after the discoloration can exist in the normal temperature range. If the ΔH value is large, each state before and after the discoloration can be easily maintained.

The complete color-elimination temperature t4 is the temperature at which the color is eliminated by frictional heat generated by the friction between the friction member and the writing surface, and is, for example, in the range of 50°C to 90°C, preferably 55°C to 85°C, and more preferably 60°C to 80°C. The complete color-development temperature t1 can be a temperature that can only be obtained in a freezer or in a cold region, and is, for example, 0°C or lower, and is preferably in the range of -50°C to -5°C, and more preferably -50°C to -10°C.

The electron-donating color-forming organic compound, the electron-accepting compound, and the reaction medium are described below.

(Electron-donating color-forming organic compound)
The electron-donating organic color-forming compound is a component that determines the color, and develops color by donating electrons to an electron-accepting compound, which is a color developer.

Examples of electron-donating color-forming organic compounds include phthalide compounds, fluoran compounds, styrinquinoline compounds, diazarhodamine lactone compounds, pyridine compounds, quinazoline compounds, and bisquinazoline compounds, with phthalide compounds and fluoran compounds being preferred.

Examples of the phthalide compound include diphenylmethane phthalide compounds, phenylindolyl phthalide compounds, indolyl phthalide compounds, diphenylmethane azaphthalide compounds, phenylindolyl azaphthalide compounds, and derivatives thereof, with phenylindolyl azaphthalide compounds and derivatives thereof being preferred.
Examples of the fluoran compound include aminofluoran compounds, alkoxyfluoran compounds, and derivatives thereof.

Examples of such electron donating organic color formers include:
3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide,
3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide,
3,3-bis(1-n-butyl-2-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-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-propylindol-3-yl)-4-azaphthalide,
3,6-bis(diphenylamino)fluoran,
3,6-dimethoxyfluoran,
3,6-di-n-butoxyfluoran,
2-methyl-6-(N-ethyl-N-p-tolylamino)fluoran,
3-chloro-6-cyclohexylaminofluoran,
2-methyl-6-cyclohexylaminofluoran,
2-(2-chloroamino)-6-dibutylaminofluoran,
2-(2-chloroanilino)-6-di-n-butylaminofluoran,
2-(3-trifluoromethylanilino)-6-diethylaminofluoran,
2-(3-trifluoromethylanilino)-6-dipentylaminofluoran,
2-(dibenzylamino)-6-diethylaminofluoran,
2-(N-methylanilino)-6-(N-ethyl-N-p-tolylamino)fluoran,
1,3-dimethyl-6-diethylaminofluoran,
2-chloro-3-methyl-6-diethylaminofluoran,
2-anilino-3-methyl-6-diethylaminofluoran,
2-anilino-3-methoxy-6-diethylaminofluoran,
2-anilino-3-methyl-6-di-n-butylaminofluoran,
2-anilino-3-methoxy-6-di-n-butylaminofluoran,
2-xylidino-3-methyl-6-diethylaminofluoran,
2-anilino-3-methyl-6-(N-ethyl-N-p-tolylamino)fluoran,
1,2-Benz-6-diethylaminofluoran,
1,2-Benz-6-(N-ethyl-N-isobutylamino)fluoran,
1,2-Benz-6-(N-ethyl-N-isoamylamino)fluoran,
2-(3-methoxy-4-dodecoxystyryl)quinoline,
spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1'(3'H)isobenzofuran]-3'-one, 2-(diethylamino)-8-(diethylamino)-4-methyl,
spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1'(3'H)isobenzofuran]-3'-one, 2-(di-n-butylamino)-8-(di-n-butylamino)-4-methyl,
spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1'(3'H)isobenzofuran]-3'-one, 2-(di-n-butylamino)-8-(diethylamino)-4-methyl,
spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1'(3'H)isobenzofuran]-3'-one, 2-(di-n-butylamino)-8-(N-ethyl-Ni-amylamino)-4-methyl,
spiro[5H-(1)benzopyrano(2,3-d)pyrimidin-5,1'(3'H)isobenzofuran]-3'-one, 2-(dibutylamino)-8-(dipentylamino)-4-methyl,
4,5,6,7-tetrachloro-3-[4-(dimethylamino)-2-methoxyphenyl]-3-(1-butyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone,
4,5,6,7-tetrachloro-3-[4-(diethylamino)-2-ethoxyphenyl]-3-(1-ethyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone,
4,5,6,7-tetrachloro-3-[4-(diethylamino)-2-ethoxyphenyl]-3-(1-pentyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone,
4,5,6,7-tetrachloro-3-[4-(diethylamino)-2-methylphenyl]-3-(1-ethyl-2-methyl-1H-indol-3-yl)-1(3H)-isobenzofuranone,
3',6'-bis[phenyl(2-methylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one,
3',6'-bis[phenyl(3-methylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one,
3',6'-bis[phenyl(3-ethylphenyl)amino]-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one,
2,6-bis(2'-ethyloxyphenyl)-4-(4'-dimethylaminophenyl)pyridine,
2,6-bis(2',4'-diethyloxyphenyl)-4-(4'-dimethylaminophenyl)pyridine,
2-(4'-dimethylaminophenyl)-4-methoxy-quinazoline,
4,4'-(ethylenedioxy)-bis[2-(4-diethylaminophenyl)quinazoline] and the like.

Fluorans include compounds having a substituent on the phenyl group that forms the xanthene ring, and compounds that have a substituent on the phenyl group that forms the xanthene ring and also have a substituent on the phenyl group that forms the lactone ring (e.g., an alkyl group such as a methyl group, or a halogen atom such as a chloro group), and that exhibit a blue or black color.

(Electron Accepting Compound)
The electron-accepting compound accepts electrons from the electron-donating organic color-forming compound and functions as a color developer.

Examples of the electron-accepting compound include compounds selected from the group of compounds having an active proton, the group of pseudo-acidic compounds (compounds that are not acids but act as acids in the reversible thermochromic composition to cause the electron-donating color-forming organic compound to develop color), and the group of compounds having electron vacancies, and compounds selected from the group of compounds having an active proton are preferred.

Examples of compounds having an active proton include compounds having a phenolic hydroxyl group and derivatives thereof, and carboxylic acids and derivatives thereof. Preferred are aromatic carboxylic acids and derivatives thereof, aliphatic carboxylic acids and derivatives thereof having 2 to 5 carbon atoms, 2-hydroxycarboxylic acid derivatives, N-substituted amino acid derivatives, acidic phosphate esters and derivatives thereof, azole compounds and derivatives thereof, 1,2,3-triazole and derivatives thereof, cyclic carbosulfimides, halohydrins having 2 to 5 carbon atoms, sulfonic acids and derivatives thereof, and inorganic acids.

Examples of pseudo-acidic compounds include metal salts of compounds having a phenolic hydroxyl group, metal salts of carboxylic acids, metal salts of acidic phosphates, metal salts of sulfonic acids, aromatic carboxylic acid anhydrides, aliphatic carboxylic acid anhydrides, mixed acid anhydrides of aromatic carboxylic acids and sulfonic acids, cycloolefin dicarboxylic acid anhydrides, urea and its derivatives, thiourea and its derivatives, guanidine and its derivatives, and halogenated alcohols.

Examples of compounds that have electron vacancies include borates, borate esters, and inorganic salts.

Among the electron-accepting compounds listed above, compounds having a phenolic hydroxyl group are preferred from the viewpoint of more effectively expressing the thermochromic properties.

Compounds having a phenolic hydroxyl group include a wide range of compounds, from monophenol compounds to polyphenol compounds, and further include bisphenol compounds and trisphenol compounds, as well as phenol-aldehyde condensation resins. Compounds having a phenolic hydroxyl group preferably have at least two benzene rings. Compounds having a phenolic hydroxyl group may have substituents such as alkyl groups, aryl groups, acyl groups, alkoxycarbonyl groups, carboxy groups and their esters, amide groups, and halogen groups.

Metals contained in metal salts of compounds having a phenolic hydroxyl group include, for example, sodium, potassium, calcium, zinc, zirconium, aluminum, magnesium, nickel, cobalt, tin, copper, iron, vanadium, titanium, lead, and molybdenum.

Examples of the compound 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,
4,4'-dihydroxybenzophenone,
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,
2-heptadecafluorooctylethane 4-hydroxybenzoate,
benzyl 4-hydroxybenzoate,
4-hydroxybenzoic acid benzyl ester,
4-hydroxybenzoic acid-o-methylbenzyl
m-methylbenzyl 4-hydroxybenzoate,
p-methylbenzyl 4-hydroxybenzoate,
p-ethylbenzyl 4-hydroxybenzoate,
p-propylbenzyl 4-hydroxybenzoate,
p-tert-butylbenzyl 4-hydroxybenzoate,
phenylethyl 4-hydroxybenzoate,
4-hydroxybenzoic acid-o-methylphenylethyl ester,
4-hydroxybenzoic acid-m-methylphenylethyl ester,
p-methylphenylethyl 4-hydroxybenzoate,
p-Ethylphenylethyl 4-hydroxybenzoate,
p-propylphenylethyl 4-hydroxybenzoate,
Examples thereof include p-tert-butylphenylethyl 4-hydroxybenzoate.

Examples of compounds having two phenolic hydroxyl groups include:
Resorcinol,
2-methylresorcinol,
4-n-hexylresorcinol,
4-n-octylresorcinol,
4-tert-octylresorcinol,
4-benzoylresorcinol,
4-nitroresorcinol,
β-Methyl resorcylate,
β-benzyl resorcylate,
2-chloro-4-pentanoylresorcinol,
6-chloro-4-pentanoylresorcinol,
2-chloro-4-hexanoylresorcinol,
6-chloro-4-hexanoylresorcinol,
2-chloro-4-propanoylresorcinol,
6-chloro-4-propanoylresorcinol,
2,6-dichloro-4-propanoylresorcinol,
6-fluoro-4-propanoylresorcinol,
2-chloro-4-phenylacetylresorcinol,
4-phenylacetyl-6-chlororesorcinol,
2-chloro-4-β-phenylpropanoylresorcinol,
6-chloro-4-β-phenylpropanoylresorcinol,
2-chloro-4-phenoxyacetylresorcinol,
6-chloro-4-phenoxyacetylresorcinol,
4-benzoyl-2-chlororesorcinol,
6-chloro-4-m-methylbenzoylresorcinol,
4-[1',3',4',9'a-tetrahydro-6'-hydroxyspiro(cyclohexane-1,9'-[9H]-xanthene)-4'a-[2H]-yl]-1,3-benzenediol,
Hydroquinone,
Methylhydroquinone,
Trimethylhydroquinone, catechol,
4-tert-butylcatechol,
1,6-dihydroxynaphthalene,
2,7-dihydroxynaphthalene,
1,5-dihydroxynaphthalene,
2,6-dihydroxynaphthalene,
2,4-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,
2,4-dihydroxy-3',4',5'-triethoxybenzophenone, and the like.

Examples of bisphenol compounds include:
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)methyl propionate,
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'-hydroxydiphenyl sulfone,
4-(4-methylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(4-ethylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(4-n-propylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(4-isopropylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(4-n-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(4-isobutylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(4-sec-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(4-tert-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(3-methylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(3-ethylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(3-n-propylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(3-isopropylbenzyloxy)-4'-dihydroxyphenyl sulfone,
4-(3-n-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(3-isobutylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(3-sec-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(3-tert-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-methylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-ethylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-n-propylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-isopropylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-n-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-isobutylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-sec-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-tert-butylbenzyloxy)-4'-hydroxydiphenyl sulfone,
2,4'-dihydroxydiphenyl sulfone,
3,4'-dihydroxydiphenyl sulfone,
4-hydroxydiphenyl sulfone,
4-methyl-4'-hydroxyphenyl sulfone,
4-ethyl-4'-hydroxydiphenyl sulfone,
4-n-propyl-4'-hydroxydiphenyl sulfone,
4-isopropyl-4'-hydroxydiphenyl sulfone,
4-chloro-4'-hydroxydiphenyl sulfone,
4-fluoro-4'-hydroxydiphenyl sulfone,
4-chloro-2-methyl-4'-hydroxydiphenyl sulfone,
4-methoxy-4'-hydroxydiphenyl sulfone,
4-ethoxy-4'-hydroxydiphenyl sulfone,
4-n-propoxy-4'-hydroxydiphenyl sulfone,
4-isopropoxy-4'-hydroxydiphenyl sulfone,
4-n-butoxy-4'-hydroxydiphenyl sulfone,
4-isobutoxy-4'-hydroxydiphenyl sulfone,
4-sec-butoxy-4'-hydroxydiphenyl sulfone,
4-tert-butoxy-4'-hydroxydiphenyl sulfone,
4-n-pentyloxy-4'-hydroxydiphenyl sulfone,
4-isopentyloxy-4'-hydroxydiphenyl sulfone,
4-(1-propenyloxy)-4'-hydroxydiphenyl sulfone,
4-(2-propenyloxy)-4'-hydroxydiphenyl sulfone,
4-benzyloxy-4'-hydroxydiphenyl sulfone,
4-(β-phenoxyethoxy)-4'-hydroxydiphenyl sulfone,
4-(β-phenoxypropoxyl)-4'-hydroxydiphenyl sulfone,
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-methyldiphenyl sulfone,
3,4,4'-trihydroxydiphenyl sulfone,
bis(3,4-dihydroxyphenyl)sulfone,
2,3,4-trihydroxydiphenyl sulfone,
4-isopropoxy-4'-hydroxydiphenyl sulfone,
4-n-propoxy-4'-hydroxydiphenyl sulfone,
4-allyloxy-4'-hydroxydiphenyl sulfone,
4-benzyloxy-4'-hydroxydiphenyl sulfone,
4-(2-propenyloxy)-4'-hydroxydiphenyl sulfone,
3-benzyl-4-benzyloxy-4'-hydroxydiphenyl sulfone,
3-phenethyl-4-phenethyloxy-4'-hydroxydiphenyl sulfone,
3-methylbenzyl-4-methylbenzyloxy-4'-hydroxydiphenyl sulfone,
4-benzyloxy-3'-benzyl-4'-hydroxydiphenyl sulfone,
4-phenethyloxy-3'-phenethyl-4'-hydroxydiphenyl sulfone,
4-methylbenzyloxy-3'-methylbenzyl-4'-hydroxydiphenyl sulfone,
α,α'-bis{4-(p-hydroxyphenylsulfone)phenoxy}-p-xylene,
4,4'-{oxybis(ethylene oxide-p-phenylene sulfonyl)}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,
1,8-bis(4-hydroxyphenylthio)-3,6-dioxaoctane and the like.

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

Examples of trisphenol compounds include
4,4',4"-Methylidynetrisphenol,
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"-ethylidynetrisphenol,
4,4',4"-ethylidynetris(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-hydroxyphenyl)-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"-Methylidynetrisphenol,
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'-[(4-3-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-hydroxyphenyl)-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"-Methylidynetris(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.

Examples of the compound 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,
1,1,2,2-tetrakis(4-hydroxy-3-methylphenyl)ethane,
1,1,2,2-tetrakis(3,5-dimethyl-4-hydroxyphenyl)ethane,
1,1,4,4-tetrakis(3,5-dimethyl-4-hydroxyphenyl)benzene,
2,2'-bis[4,4-(4-hydroxy-3-methylphenyl)cyclohexyl]propane,
2,2'-[(3,4-dihydroxyphenyl)methylene]bis(3,5-dimethylphenol),
3,6-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]catechol,
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[3-(2-hydroxybenzyl)-4-hydroxy-5-methylphenyl]methane,
bis[3-(3-hydroxybenzyl)-4-hydroxy-5-methylphenyl]methane,
bis[3-(4-hydroxybenzyl)-4-hydroxy-5-methylphenyl]methane,
Bis[3-(2-hydroxybenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[3-(2-hydroxybenzyl)-3-hydroxy-5-methylphenyl]methane,
bis[3-(2-hydroxybenzyl)-4-hydroxy-5-methylphenyl]methane,
Bis[3-(3-hydroxy-2-methylbenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[3-(4-hydroxy-3-methylbenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[3-(3-hydroxy-4-methylbenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[3-(2-hydroxy-3-methylbenzyl)-2-hydroxy-5-methylphenyl]methane,
α,α',α",α'"-tetrakis(4-hydroxyphenyl)benzene, bis[3-(3,6-dimethyl-2-hydroxybenzyl)-2-hydroxy-5-methylphenyl]methane,
[3-(3,6-dimethyl-2-hydroxybenzyl)-2-hydroxy-5-methylphenyl][3-(2,5-dimethyl-4-hydroxybenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[3-(2,5-dimethyl-4-hydroxybenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[3-(3,5-dimethyl-4-hydroxybenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[3-(2-hydroxy-3,4,6-trimethylbenzyl)-2-hydroxy-5-methylphenyl]methane,
Bis[2-hydroxy-3-(4-hydroxy-2,3,5-trimethylbenzyl)-5-methylphenyl]methane,
4,4',4",4'"-tetrakis(4-hydroxyphenyl)-1,1'-bicyclohexyl,
2,2'-bis[4,4-bis(4-hydroxyphenyl)cyclohexyl]propane,
4,4',4",4'"-tetrakis(4-hydroxy-3-methylphenyl)-1,1'-bicyclohexyl,
Bis[3-(5-cyclohexyl-4-hydroxy-2-methylbenzyl)-4-hydroxy-5-methylphenyl]methane,
4,4',4",4'"-tetrakis(3,5-dimethyl-4-hydroxyphenyl)-1,1'-bicyclohexyl,
1,1-bis[3-(2-hydroxy-5-methylbenzyl)-5-cyclohexyl-4-hydroxyphenyl]cyclohexane,
1,1-bis[3-(3,5-dimethyl-4-hydroxybenzyl)-5-cyclohexyl-4-hydroxyphenyl]cyclohexane,
1,1-bis[3-(5-cyclohexyl-4-hydroxy-2-methylbenzyl)-5-cyclohexyl-4-hydroxyphenyl]cyclohexane,
4,6-bis[α-methyl-(4-hydroxyphenyl)benzyl-1,3-benzenediol,
2,2-bis[3-(4-hydroxy-3-methylbenzyl)-4-hydroxy-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(4-hydroxy-3-isopropylphenyl)-1,1'-bicyclohexyl,
4,4'-bis[(3,4-dihydroxyphenyl)methylene]bis(2-isopropylphenol) 2,4,6-tris(4-hydroxybenzyl)-1,3-benzenediol,
4,6-bis(3,5-dimethyl-4-hydroxybenzyl)pyrogallol,
3,3'-[(2-hydroxyphenyl)methylene]bis(5-methylcatechol),
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)resorcinol,
2,4,6-tris(3,5-dimethyl-2-hydroxybenzyl)resorcinol,
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)pyrogallol,
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"-ethylidynetris{[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"-ethylidynetris[2,6-bis(2-hydroxybenzyl)phenol],
4,4',4"-ethylidynetris[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.

Carboxylic acids and their derivatives include, for example:
3,5-di(α-methylbenzyl)salicylic acid,
4-(2-p-methoxyphenyloxyethoxy)salicylic acid,
4-hydroxyphenylbenzoic acid,
p-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-(p-tolylaminocarbonyl)-methionine,
N-(phenylaminocarbonyl)-methionine,
N-(p-tolylaminocarbonyl)-tyrosine,
N-(m-tolylaminocarbonyl)-methionine,
N-(p-tolylaminocarbonyl)-methionine,
N-(phenylaminocarbonyl)-methionine,
N-(m-tolylaminocarbonyl)-valine,
N-(m-tolylaminocarbonyl)-phenylglycine,
N-(m-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,
2-O-(phenethylaminocarbonyl)-lactic acid and the like.

Examples of acidic phosphate ester compounds include 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, tetracosyl acid phosphate, monobutyl phosphate, dibutyl phosphate, monoisodecyl phosphate, bis(2-ethylhexyl)phosphate, etc.

As described above, the electron-accepting compound is preferably a compound having a phenolic hydroxyl group, since it can more effectively express the thermochromic property, but compounds selected from the group consisting of aromatic carboxylic acids, aliphatic carboxylic acids having 2 to 5 carbon atoms, carboxylic acid metal salts, acidic phosphate esters and their metal salts, and 1,2,3-triazole and its derivatives can also be effectively used.

(Reaction medium that determines the temperature at which the color reaction occurs)
The reversible thermochromic composition includes an electron-accepting compound and a reaction medium that determines the temperature at which a color reaction between an electron-donating organic color-forming compound and the electron-accepting compound occurs. The reaction medium causes the electron-donating reaction between the electron-donating organic color-forming compound and the electron-accepting compound to occur reversibly in a specific temperature range.

Examples of reaction media include esters, ketones, ethers, alcohols, and acid amides.

The reaction medium may be a carboxylate compound that shows a ΔT value (melting point-cloud point) of 5°C or more and less than 50°C and is capable of forming a reversible thermochromic composition that exhibits color memory and changes color while showing a large hysteresis characteristic in the color density-temperature curve (the curve plotting the change in color density due to temperature change is different when the temperature is changed from a low temperature side to a high temperature side than when the temperature is changed from a high temperature side to a low temperature side).
Examples of such carboxylate ester compounds include carboxylate esters containing a substituted aromatic ring in the molecule, esters of carboxylic acids containing an unsubstituted aromatic ring and aliphatic alcohols having 10 or more carbon atoms, carboxylate esters containing a cyclohexyl group in the molecule, esters of fatty acids having 6 or more carbon atoms and unsubstituted aromatic alcohols or phenols, esters of fatty acids having 8 or more carbon atoms and branched aliphatic alcohols, esters of dicarboxylic acids and aromatic alcohols or branched aliphatic alcohols, dibenzyl cinnamate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, dicetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearin, dimyristin, and distearin.

In addition, as the reaction medium, for example, a fatty acid ester compound obtained from an aliphatic monohydric alcohol having an odd number of carbon atoms of 9 or more and an aliphatic carboxylic acid having an even number of carbon atoms, and a fatty acid ester compound having 17 to 23 carbon atoms obtained from n-pentyl alcohol or n-heptyl alcohol and an aliphatic carboxylic acid having an even number of carbon atoms of 10 to 16 are also effective.
Examples of such aliphatic ester compounds include n-pentadecyl acetate, n-tridecyl butyrate, n-pentadecyl butyrate, n-undecyl caproate, n-tridecyl caproate, n-pentadecyl caproate, n-nonyl caprylate, n-undecyl caprylate, n-tridecyl caprylate, n-pentadecyl caprylate, n-heptyl caprate, n-nonyl caprate, n-undecyl caprate, n-tridecyl caprate, n-pentadecyl caprate, n-pentyl laurate, n-heptyl laurate, n-nonyl laurate, n-undecyl laurate, n-tridecyl laurate, n-pentadecyl laurate, n-pentyl myristate, n-heptyl myristate, n-nonyl myristate, n-undecyl myristate, n-tridecyl myristate, n-pentadecyl myristate, n-pentyl palmitate, n-heptyl palmitate, n-nonyl palmitate, n-undecyl palmitate, n-tridecyl palmitate, n-pentadecyl palmitate, n-nonyl stearate, n-undecyl stearate, n-tridecyl stearate, n-pentadecyl stearate, n-nonyl eicosanoate, n-undecyl eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate, n-nonyl behenate, n-undecyl behenate, n-tridecyl behenate, and n-pentadecyl behenate.

As ketones, aliphatic ketones having 10 or more carbon atoms are effective, such as 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, 5-undecanone, 2-dodecanone, 3-dodecanone, 4-dodecanone, 5-dodecanone, 2-tridecanone, 3-tridecanone, 2-tetradecanone, 2-pentadecanone, 8-pentadecanone, 2-hexadecanone, 3-hexadecanone, 9-heptadecanone, 2-pentadecanone, 2-octadecanone, 2-nonadecanone, 10-nonadecanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, laurone, stearone, etc.

In addition, ketones include aryl alkyl ketones having 12 to 24 carbon atoms, such as n-octadecanophenone, n-heptadecanophenone, n-hexadecanophenone, n-pentadecanophenone, n-tetradecanophenone, 4-n-dodecaacetophenone, n-tridecanophenone, 4-n-undecanoacetophenone, n-laurophenone, 4-n-decanoacetophenone, n-undecanophenone, 4-n-nonylacetophenone, n-decanophenone, 4-n-octylacetophenone, n -nonanophenone, 4-n-heptylacetophenone, n-octanophenone, 4-n-hexylacetophenone, 4-n-cyclohexylacetophenone, 4-tert-butylpropiophenone, n-heptaphenone, 4-n-pentylacetophenone, cyclohexyl phenyl ketone, benzyl-n-butyl ketone, 4-n-butylacetophenone, n-hexanophenone, 4-isobutylacetophenone, 1-acetonaphthone, 2-acetonaphthone, cyclopentyl phenyl ketone, etc.

As ethers, aliphatic ethers having 10 or more carbon atoms are effective, such as dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, didodecyl ether, ditridecyl ether, ditetradecyl ether, dipentadecyl ether, dihexadecyl ether, dioctadecyl ether, decanediol dimethyl ether, undecanediol dimethyl ether, dodecanediol dimethyl ether, tridecanediol dimethyl ether, decanediol diethyl ether, undecanediol diethyl ether, etc.

As alcohols, aliphatic monohydric saturated alcohols having 10 or more carbon atoms are effective, such as decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, eicosyl alcohol, and docosyl alcohol.

Examples of acid amides include hexanoic acid amide, heptanoic acid amide, octanoic acid amide, nonanoic acid amide, decanoic acid amide, undecanoic acid amide, lauric acid amide, tridecanoic acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, and docosanoic acid amide.

（ここで、Ｒ１は水素原子又はメチル基であり、ｑ１は０～２の整数であり、Ｘ１のいずれか一方は－（ＣＨ２）ｋＯＣＯＲ’又は－（ＣＨ２）ｋＣＯＯＲ’であり、他方は水素原子であり、ｋは０～２の整数であり、Ｒ’は炭素数４以上のアルキル基又はアルケニル基であり、Ｙ１はそれぞれ独立に炭素数１以上４以下のアルキル基若しくはメトキシ基、又はハロゲンであり、ｐ１はそれぞれ独立に０～３の整数である。） The reaction medium may also be a compound represented by the following general formula (1):

(wherein R1 is a hydrogen atom or a methyl group, q1 is an integer of 0 to 2, one of X1 is -(CH2)kOCOR' or -(CH2)kCOOR' and the other is a hydrogen atom, k is an integer of 0 to 2, R' is an alkyl group or an alkenyl group having 4 or more carbon atoms, each Y1 is independently an alkyl group or a methoxy group having 1 to 4 carbon atoms, or a halogen, and each p1 is independently an integer of 0 to 3.)

In the compound represented by general formula (1), when R1 is a hydrogen atom, a reversible thermochromic composition having a wider hysteresis width is obtained, which is preferable, and further, when R1 is a hydrogen atom and m is 0, it is more preferable.

（ここで、Ｒ１ａは、炭素数８以上のアルキル基又はアルケニル基、好ましくは炭素数１０以上２４以下のアルキル基、更に好ましくは炭素数１２以上２２以下のアルキル基である。） The compound represented by the general formula (1) is more preferably a compound represented by the following general formula (1a):

(Here, R1a is an alkyl group or alkenyl group having 8 or more carbon atoms, preferably an alkyl group having 10 to 24 carbon atoms, and more preferably an alkyl group having 12 to 22 carbon atoms.)

Examples of the compound represented by general formula (1a) include 4-benzyloxyphenylethyl octanoate, 4-benzyloxyphenylethyl nonanoate, 4-benzyloxyphenylethyl decanoate, 4-benzyloxyphenylethyl undecanoate, 4-benzyloxyphenylethyl dodecanoate, 4-benzyloxyphenylethyl tridecanoate, 4-benzyloxyphenylethyl tetradecanoate, 4-benzyloxyphenylethyl pentadecanoate, 4-benzyloxyphenylethyl hexadecanoate, 4-benzyloxyphenylethyl heptadecanoate, and 4-benzyloxyphenylethyl octadecanoate.

（ここで、Ｒ２は炭素数８以上のアルキル基又はアルケニル基であり、ｐ２はそれぞれ独立に０～３の整数であり、Ｘ２はそれぞれ独立に炭素数１以上４以下のアルキル基、炭素数１以上４以下のアルコキシ基、又はハロゲンである。） The reaction medium may also be a compound represented by the following general formula (2):

(Here, R2 is an alkyl group or alkenyl group having 8 or more carbon atoms, p2 is independently an integer from 0 to 3, and X2 is independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen.)

Examples of the compound represented by general formula (2) include 1,1-diphenylmethyl octanoate, 1,1-diphenylmethyl nonanoate, 1,1-diphenylmethyl decanoate, 1,1-diphenylmethyl undecanoate, 1,1-diphenylmethyl dodecanoate, 1,1-diphenylmethyl tridecanoate, 1,1-diphenylmethyl tetradecanoate, 1,1-diphenylmethyl pentadecanoate, 1,1-diphenylmethyl hexadecanoate, 1,1-diphenylmethyl heptadecanoate, and 1,1-diphenylmethyl octadecanoate.

（ここで、Ｘ３はそれぞれ独立に炭素数１以上４以下のアルキル基、メトキシ基、又はハロゲン原子のいずれかであり、ｐ３はそれぞれ独立に０～３の整数であり、ｑ３は１以上２０以下の整数である。） The reaction medium may also be a compound represented by the following general formula (3):

(wherein, each X3 is independently any one of an alkyl group having 1 to 4 carbon atoms, a methoxy group, or a halogen atom, each p3 is independently an integer of 0 to 3, and q3 is an integer of 1 to 20.)

Examples of compounds represented by general formula (3) include a diester of malonic acid and 2-[4-(4-chlorobenzyloxy)phenyl)]ethanol, a diester of succinic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of succinic acid and 2-[4-(3-methylbenzyloxy)phenyl)]ethanol, a diester of glutaric acid and 2-(4-benzyloxyphenyl)ethanol, a diester of glutaric acid and 2-[4-(4-chlorobenzyloxy)phenyl)]ethanol, a diester of adipic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of pimelic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of suberic acid and 2-(4-benzyloxyphenyl)ethanol, a diester of suberic acid and 2-[4-(3-methyl diester of 2-(4-benzyloxy)phenyl)ethanol, diester of suberic acid and 2-(4-(4-chlorobenzyloxy)phenyl)ethanol, diester of suberic acid and 2-(4-(2,4-dichlorobenzyloxy)phenyl)ethanol, diester of azelaic acid and 2-(4-benzyloxyphenyl)ethanol, diester of sebacic acid and 2-(4-benzyloxyphenyl)ethanol, diester of 1,10-decanedicarboxylic acid and 2-(4-benzyloxyphenyl)ethanol, diester of 1,18-octadecanedicarboxylic acid and 2-(4-benzyloxyphenyl)ethanol, diester of 1,18-octadecanedicarboxylic acid and 2-(4-methylbenzyloxy)phenyl)ethanol, etc.

（ここで、Ｒ４はそれぞれ独立に炭素数１以上２１以下のアルキル基又はアルケニル基であり、ｐ４はそれぞれ独立に１以上３以下の整数である。） The reaction medium may also be a compound represented by the following general formula (4):

(wherein, each R4 is independently an alkyl or alkenyl group having 1 to 21 carbon atoms, and each p4 is independently an integer of 1 to 3.)

Examples of compounds represented by general formula (4) include diesters of 1,3-bis(2-hydroxyethoxy)benzene and capric acid, diesters of 1,3-bis(2-hydroxyethoxy)benzene and undecanoic acid, diesters of 1,3-bis(2-hydroxyethoxy)benzene and lauric acid, diesters of 1,3-bis(2-hydroxyethoxy)benzene and myristic acid, diesters of 1,3-bis(2-hydroxyethoxy)benzene and palmitic acid, diesters of 1,3-bis(2-hydroxyethoxy)benzene and cyclohexanoic acid carboxylic acid, diesters of 1,3-bis(2-hydroxyethoxy)benzene and cyclohexanoic acid propionic acid, diesters of 1,4-bis(hydroxymethoxy)benzene and butyric acid, and diesters of 1,4-bis(hydroxymethoxy)benzene and isopropyl alcohol. Examples include diesters of valeric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and acetic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and propionic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and valeric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and caproic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and caprylic acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and capric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and lauric acid, diesters of 1,4-bis(2-hydroxyethoxy)benzene and myristic acid, and diesters of 1,4-bis(2-hydroxyethoxy)benzene and cyclohexanepropionic acid.

（ここで、Ｘ５はそれぞれ独立に炭素数１以上４以下のアルキル基、炭素数１以上４以下のアルコキシ基、又はハロゲン原子のいずれかであり、ｐ５はそれぞれ独立に０以上３以下の整数であり、ｑ５は１以上２０以下の整数である。） The reaction medium may also be a compound represented by the following general formula (5):

(wherein, each X5 is independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; each p5 is independently an integer of 0 to 3; and each q5 is an integer of 1 to 20.)

Examples of compounds represented by general formula (5) include a diester of succinic acid and 2-phenoxyethanol, a diester of suberic acid and 2-phenoxyethanol, a diester of sebacic acid and 2-phenoxyethanol, a diester of 1,10-decanedicarboxylic acid and 2-phenoxyethanol, and a diester of 1,18-octadecanedicarboxylic acid and 2-phenoxyethanol.

（ここで、Ｒ６は炭素数４以上２２以下のアルキル基、シクロアルキルアルキル基、シクロアルキル基、炭素数４以上２２以下のアルケニル基のいずれかであり、Ｘ６は水素原子、炭素数１以上４以下のアルキル基、炭素数１以上４以下のアルコキシ基、ハロゲン原子のいずれかであり、ｑ６は０又は１である。） The reaction medium may also be a compound represented by the following general formula (6):

(wherein R6 is any one of an alkyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, a cycloalkyl group, and an alkenyl group having 4 to 22 carbon atoms; X6 is any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom; and q6 is 0 or 1.)

Examples of the compound represented by the general formula (6) include decyl 4-phenylbenzoate, lauryl 4-phenylbenzoate, myristyl 4-phenylbenzoate, cyclohexylethyl 4-phenylbenzoate, octyl 4-biphenylacetate, nonyl 4-biphenylacetate, decyl 4-biphenylacetate, lauryl 4-biphenylacetate, myristyl 4-biphenylacetate, tridecyl 4-biphenylacetate, pentadecyl 4-biphenylacetate, cetyl 4-biphenylacetate, cyclopentyl 4-biphenylacetate, cyclohexylmethyl 4-biphenylacetate, hexyl 4-biphenylacetate, and cyclohexylmethyl 4-biphenylacetate.

（ここで、Ｒ７は炭素数３以上１８以下のアルキル基、又は炭素数３以上１８以下の脂肪族アシル基のいずれかであり、Ｘ７は水素原子、炭素数１以上３以下のアルキル基、炭素数１又は２のアルコキシ基、ハロゲン原子のいずれかであり、Ｙ７は水素原子、メチル基のいずれかであり、Ｚ７は水素原子、炭素数１以上４以下のアルキル基、炭素数１又は２のアルコキシ基、ハロゲン原子のいずれかである。） The reaction medium may also be a compound represented by the following general formula (7):

(Here, R7 is either an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X7 is either a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, or a halogen atom; Y7 is either a hydrogen atom or a methyl group; and Z7 is either 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 general formula (7) include phenoxyethyl 4-butoxybenzoate, phenoxyethyl 4-pentyloxybenzoate, phenoxyethyl 4-tetradecyloxybenzoate, esters of phenoxyethyl 4-hydroxybenzoate and dodecanoic acid, and dodecyl ether of phenoxyethyl vanillate.

（ここで、Ｒ８は炭素数４以上２２以下のアルキル基、炭素数４以上２２以下のアルケニル基、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であり、Ｘ８は、それぞれ独立にアルキル基、アルコキシ基、ハロゲン原子のいずれかであり、ｐ８は０又は１であり、ｑ８は０以上５以下であり、ｒ８は０以上４以下である。） The reaction medium may also be a compound represented by the following general formula (8):

(Here, R8 is any one of an alkyl group having 4 to 22 carbon atoms, an alkenyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, and a cycloalkyl group; each X8 is independently any one of an alkyl group, an alkoxy group, and a halogen atom; p8 is 0 or 1; q8 is 0 to 5; and r8 is 0 to 4.)

Examples of compounds represented by general formula (8) include the benzoate ester of octyl p-hydroxybenzoate, the benzoate ester of decyl p-hydroxybenzoate, the p-methoxybenzoate ester of heptyl p-hydroxybenzoate, the o-methoxybenzoate ester of dodecyl p-hydroxybenzoate, and the benzoate ester of cyclohexylmethyl p-hydroxybenzoate.

（ここで、Ｒ９は炭素数３以上１７以下のアルキル基、炭素数３以上８以下のシクロアルキル基、炭素数５以上８以下のシクロアルキルアルキル基であり、Ｘ９は水素原子、炭素数１以上５以下のアルキル基、メトキシ基、エトキシ基、ハロゲン原子であり、ｐ９は１以上３以下の整数である。） The reaction medium may also be a compound represented by the following general formula (9):

(wherein R9 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; X9 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a methoxy group, an ethoxy group, or a halogen atom; and p9 is an integer of 1 to 3.)

Examples of compounds represented by general formula (9) include a diester of 4-phenylphenol ethylene glycol ether and cyclohexane carboxylic acid, a diester of 4-phenylphenol diethylene glycol ether and lauric acid, a diester of 4-phenylphenol triethylene glycol ether and cyclohexane carboxylic acid, a diester of 4-phenylphenol ethylene glycol ether and octanoic acid, a diester of 4-phenylphenol ethylene glycol ether and nonanoic acid, a diester of 4-phenylphenol ethylene glycol ether and decanoic acid, and a diester of 4-phenylphenol ethylene glycol ether and myristic acid.

The blending ratio of the electron donating organic color-forming compound, the electron accepting compound, and the reaction medium depends on the concentration, color change temperature, color change form, and the type of these components, but from the viewpoint of obtaining the desired color change characteristics, the electron accepting compound is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 50 parts by mass or less, more preferably 20 parts by mass or less, per 1 part by mass of the electron donating organic color-forming compound, and the reaction medium is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 800 parts by mass or less, more preferably 200 parts by mass or less.

The method for encapsulating the reversible thermochromic composition in the microcapsules is not particularly limited, and examples thereof include the interfacial polymerization method, the interfacial polycondensation method, the in situ polymerization method, the liquid hardening coating method, the phase separation method from an aqueous solution, the phase separation method from an organic solvent, the melt dispersion cooling method, the air suspension coating method, and the spray drying method, and may be appropriately selected depending on the application.

Materials for the microcapsules include organic resins, such as epoxy resins, urea resins, urethane resins, and isocyanate resins.

By providing a secondary resin coating on the surface of the microcapsules according to the purpose, durability can be imparted, and the surface properties can be modified for practical use.

The mass ratio of the microcapsule (i.e., the microcapsule wall portion not encapsulating the reversible thermochromic composition) to the reversible thermochromic composition is preferably 1 part by mass or more, more preferably 1 part by mass or more, and preferably 7 parts by mass or less, more preferably 6 parts by mass or less, of the reversible thermochromic composition per part by mass of the microcapsule. By making the reversible thermochromic composition 7 parts by mass or less per part by mass of the microcapsule, it becomes easy to make the microcapsule wall have an appropriate wall thickness without becoming too thin, and it becomes easy to improve the heat resistance and pressure resistance of the microcapsule pigment. In addition, by making the reversible thermochromic composition 1 part by mass or more per part by mass of the microcapsule, it becomes easy to improve the color density and clarity when the microcapsule pigment develops color.

The average particle size of the microcapsules is, for example, in the range of 0.01 to 50 μm, preferably 0.1 to 30 μm, and more preferably 0.5 to 20 μm, which is practical.

The average particle diameter of the microcapsule pigment may be determined, for example, by using Mountech's image analysis particle size distribution measurement software "MacView" to determine the particle area, calculating the projected area circle equivalent diameter (Heywood diameter) from the area of the particle area, and measuring the average particle diameter of the particles equivalent to a sphere of equal volume using this value.

In addition, when the particle diameter of all or most of the particles exceeds 0.2 μm, the average particle diameter of the microencapsulated pigment may be measured as the average particle diameter of particles equivalent to an equal volume sphere by the Coulter method using, for example, a particle size distribution measuring device "Multisizer 4e" manufactured by Beckman Coulter, Inc. In addition, the volume-based particle diameter and average particle diameter (median diameter) of the microencapsulated pigment may be measured using, for example, a laser diffraction/scattering type particle size distribution measuring device "LA-300" manufactured by Horiba, Ltd., calibrated based on values measured using a standard sample or a measuring device using the Coulter method (electrical detection zone method). __

The microencapsulated pigments can be used alone or in combination of two or more types. The content of the microencapsulated pigment in the ink composition is preferably 3 to 20% by mass, and more preferably 5 to 15% by mass. When the content of the microencapsulated pigment is within the above range, a better balance is achieved between the color development of the microencapsulated pigment in the handwriting and the brilliance of the luster pigment.

The total content of the microencapsulated pigment and the luster pigment in the ink composition is, for example, 2 to 45% by mass, preferably 3 to 40% by mass, and more preferably 5 to 30% by mass. When the total content of the microencapsulated pigment and the luster pigment is within the above range, better color development and luster can be achieved, and better erasing and removability can also be achieved.

The ratio of the content of the microencapsulated pigment to the total content of the luster pigment in the ink composition is, for example, 0.5 to 200, preferably 1 to 150, more preferably 1 to 100, and even more preferably 1.5 to 50. When the ratio of the content of the microencapsulated pigment to the total content of the luster pigment is within the above range, a better balance is achieved between the color development of the microencapsulated pigment in the handwriting and the luster of the luster pigment.

The ink composition contains at least one type of thickener. By containing a thickener, it is possible to suppress the settling and aggregation of the glitter pigment. The thickener may function as a shear thinning agent. Examples of thickeners include polysaccharides, particularly heteropolysaccharides. Specific examples include xanthan gum, welan gum, succinoglycan (average molecular weight of about 1 to 8 million), which is an organic acid-modified heteropolysaccharide whose constituent monosaccharides are glucose and galactose, guar gum, locust bean gum and its derivatives, diutan gum, etc. Xanthan gum is preferable as the polysaccharide. The thickeners can be used alone or in combination of two or more types.

The content of the thickener in the ink composition is preferably 0.17 to 0.55% by mass, and more preferably 0.2 to 0.5% by mass. If the content of the thickener is 0.17% by mass or more, sufficient ink viscosity is obtained, and aggregation and sedimentation of the microcapsule pigment and the glittering pigment can be sufficiently suppressed. On the other hand, if the content of the thickener is 0.55% by mass or less, the ink viscosity does not become too high, and good handwriting can be formed.

The ink composition preferably contains a sugar mixture containing 30% by mass or more of starch saccharification products with 8 or more sugars and/or their reduced products (hereinafter referred to as sugars). This can further improve drying resistance and provide anti-sagging performance.

The sugar mixture preferably contains 50% by mass or more of saccharides with 8 or more sugars, and more preferably contains 70% by mass or more of saccharides with 8 or more sugars. In order to impart drying resistance, it is necessary to form a certain amount of a dry film, but monosaccharides or disaccharides do not form a sufficient dry film, so the effect on drying resistance is small, and when applied to a ballpoint pen, sagging is likely to occur when the tip is left facing downward (upside down) due to their high water absorption. In addition, about 3 to 7 sugars have lower water absorption than monosaccharides or disaccharides, but do not achieve sufficient drying resistance. Furthermore, if a large amount is added to obtain sufficient drying resistance, the water absorption may become high and cause sagging, or the added sugar may not be completely dissolved, increasing the solid content in the ink composition and decreasing drying resistance. Sugars have the characteristic that as the molecular weight increases, their hygroscopicity decreases and they are more likely to form a dry film. Therefore, by using sugars with 8 or more sugars, sagging under high humidity conditions can be prevented and drying resistance can be improved. Furthermore, it also improves heat resistance, acid resistance, microbial resistance, and other properties, and can maintain a stable state in the ink.

As sugars with 8 or more sugars, starch saccharification products obtained by enzymatic decomposition of starch, and reduced starch saccharification products obtained by reducing the terminal groups of the starch saccharification products can be used. Furthermore, when starch is decomposed, sugars with various degrees of polymerization are produced, so it is technically difficult to completely isolate only the sugars with 8 or more sugars, and the production costs are high. Therefore, in a sugar mixture containing sugars with 7 or less sugars, a sugar mixture containing 30% by mass or more of the sugars with 8 or more sugars can be used, which allows the ink to fully obtain the above-mentioned properties and imparts drying resistance and sagging prevention properties. Examples of sugar mixtures include products obtained by decomposing starch (e.g., enzymatic decomposition), etc.

The content of the sugar mixture in the ink composition is preferably 0.5 to 10% by mass. If it is 0.5% by mass or more, the drying resistance is effectively improved, and if it is 10% by mass or less, problems such as the viscosity of the ink composition increasing due to incorporation, causing bleeding or blobbing, or impeding tracking, can be easily avoided, and there is no adverse effect on the good drying resistance. The content of the sugar mixture is more preferably 1 to 8% by mass.

The ink composition may contain known components as long as they do not impair the effects of the present invention. For example, the ink composition may contain alkyd resins, acrylic resins, styrene-maleic acid copolymers, cellulose derivatives, polyvinylpyrrolidone, polyvinyl alcohol, etc., if necessary, to provide adhesion to the paper surface and viscosity.

Furthermore, various additives may be contained as necessary. Examples of additives include higher fatty acids such as oleic acid, nonionic surfactants having long-chain alkyl groups, polyether-modified silicone oils, thiophosphite triesters such as tri(alkoxycarbonylmethyl ester) thiophosphite and tri(alkoxycarbonylethyl ester) thiophosphite, monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, or lubricants such as metal salts, ammonium salts, amine salts, and alkanolamine salts thereof.

In addition, inorganic salts such as sodium carbonate, sodium phosphate, and sodium acetate, pH adjusters such as organic basic compounds such as water-soluble amine compounds, rust inhibitors such as benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, and saponin, carbolic acid, sodium salt of 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetrachloro-4-(methyl It may also contain preservatives or antifungals such as (phenylsulfonyl)pyridine, ascorbic acid, ascorbic acid derivatives, natural or synthetic polyphenols, N-vinylpyrrolidone oligomers, kojic acid, hydroxylamines, oxime derivatives, α-glucosyl rutin, oxygen absorbers such as phosphonates, phosphinates, sulfites, sulfoxylates, dithionites, thiosulfates, thiourea dioxide, formamidinesulfinic acid, glutathione, and reaction products of n-butylaldehyde and aniline, as well as defoamers and dispersants.

The ink composition contains water, but may contain a water-soluble organic solvent in addition to water. When a water-soluble organic solvent is contained, it is preferable to contain it to the extent that various problems such as poor ink tracking due to an increase in ink viscosity, poor drying of handwriting, and bleeding of handwriting do not occur, or the ink composition may not contain a water-soluble organic solvent. Examples of water-soluble organic solvents include glycol-based water-soluble organic solvents, and specific examples include ethylene glycol, diethylene glycol, thiodiethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, 1,3-butylene glycol, glycerin, and furfuryl alcohol.

The ink composition has a viscosity of 7000 to 25000 mPa·s measured at a shear rate of 0.1 sec ^-1 , and a viscosity of 17 to 30 mPa·s measured at a shear rate of 1000 sec ^-1 . The preferred viscosity of the ink composition is 7500 to 20000 mPa·s at a shear rate of 0.1 sec ^-1 , and 20 to 30 mPa·s at a shear rate of 1000 sec ^-1 . When the viscosity of the ink composition is in the above range, the precipitation and aggregation of the glittering pigment in the ink composition in a stationary state is suppressed, and the ink discharge from the ballpoint pen tip during writing is improved, and a thermochromic handwriting with excellent glittering properties can be formed. The viscosity of the ink composition can be adjusted to a desired range by appropriately selecting the ink composition such as the microcapsule pigment, the content of the glittering pigment, and the content of the thickener.
The viscosity of the ink composition can be measured at 20° C. using a rheometer "DHR-2" manufactured by TA Instruments.

Furthermore, the water-based ink composition preferably has a shear thinning index n, measured at 20° C. and represented by the following formula (1), of 0.20 to 0.35, and more preferably 0.25 to 0.35.
T = Kjn (1)
Here, T is the shear stress [N/m ² ], K is the viscosity coefficient (constant), and J is the shear rate [sec ^-1 ].
This allows the ink at the tip of the pen to be ejected without pooling in the gap between the ball and the ball-gripping portion when writing, resulting in clear handwriting with excellent brilliance and color development.

The shear thinning index n can be measured, for example, using a rheometer "DHR-2" manufactured by TA Instruments Co., Ltd., and n is calculated by applying the shear rates of 0.1 sec ^-1 and 1000 sec ^-1 and the shear stresses (shear stresses) obtained at these shear rates to the above formula (1).

The ink composition is prepared by adding and stirring the glitter pigment, microencapsulated pigment, and various additives as necessary to an aqueous medium containing water and a water-soluble organic solvent, and then adding a dispersion in which a thickener has been dispersed in a separately prepared solvent, or the thickener itself, and stirring the mixture.

The ink composition can be used as a writing ink for ballpoint pens.

The ink composition can be applied to a ballpoint pen having a barrel that contains the ink composition and a ballpoint pen tip that dispenses the ink composition contained in the barrel.

The structure and shape of the ballpoint pen itself are not particularly limited. For example, a ballpoint pen may have an ink reservoir tube filled with an ink composition inside a barrel, the ink reservoir tube communicating with a ballpoint pen tip having a ball attached to the tip, and a backflow prevention plug in close contact with the end face of the ink composition contained in the ink reservoir tube. A ballpoint pen constructed using an ink composition of the above configuration has good ink ejection properties from the writing tip and excellent handwriting formation properties.

Examples of ballpoint pen tips that can be used include ballpoint pen tips in which the ball is held in a ball-holding portion formed by pressing the tip of a metal pipe inward from the outside, ballpoint pen tips in which the ball is held in a ball-holding portion formed by cutting a metal material with a drill or the like, ballpoint pen tips in which a resin ball receiving seat is provided inside a metal or plastic tip, and ballpoint pen tips in which the ball held in the ballpoint pen tip is biased forward by a spring body. The ball can be made of cemented carbide, stainless steel, ruby, ceramic, resin, rubber, etc., and can have a diameter of, for example, 0.3 mm to 2.0 mm, preferably 0.3 mm to 1.5 mm, and more preferably 0.3 mm to 1.0 mm.

As an example of a more specific structure of a ballpoint pen tip that can be applied to a ballpoint pen, there is a ballpoint pen tip that is formed by cutting a metal material with a drill or the like and holds a ball in a ball-holding chamber, has an ink flow hole in the center of the bottom wall of the ball-holding chamber, and has ink flow grooves that extend radially from the ink flow hole, and places a ball on the bottom wall and crimps the tip end inward, so that a part of the ball protrudes from the tip end and is held rotatably.

The inner diameter of the ink flow hole is preferably set within the range of 40% to 80% of the ball diameter, and more preferably within the range of 50% to 70%. In addition, the amount of movement (clearance) in the direction of the ball's vertical axis (axis perpendicular to the radial direction of the ballpoint pen tip) within the ballpoint pen tip is preferably set within the range of 25 to 60 μm, and more preferably within the range of 40 to 60 μm.

The ink flow grooves are not particularly limited in number, shape, or depth, but taking into consideration the following: improving the ink discharge from the ballpoint pen tip to provide a good writing feel and good handwriting formability; making it difficult for the ink to move within the ink flow grooves when no shear force is applied to the ink due to the rotation of the ball, such as when not writing; and suppressing air from flowing in from the pen tip and mixing with the ink when the pen tip is facing upwards, it is preferable that the ink flow grooves have a width of 0.1 to 0.2 mm. Furthermore, when the ball is placed on the bottom wall of the ball holding chamber, the projected area of the ink flow groove that opens outward in the radial direction of the ball point pen tip from the contact part between the ball holding chamber and the ball, which is formed on the bottom wall of the ball holding chamber (hereinafter sometimes referred to as the opening projected area of the ink flow groove) is preferably 0.015 to ^0.03 mm2 per opening, taking into consideration improving the ink discharge from the ball point pen tip, improving the writing feel and handwriting formability, while suppressing clogging and retention of the luster pigment within the ball point pen tip.
The projected area of the ink flow groove is the area of the ink flow groove projected onto a plane.

The method for measuring the opening projected area of the ink flow groove is as follows: a ball is placed on the bottom wall of the ball holding chamber and rotated to form a wear mark on the bottom wall of the ball holding chamber, and the wear mark is used as the contact point between the ball and the bottom wall of the ball holding chamber. Imaginary circles of maximum diameter are drawn that are tangent to each of the outermost boundary lines of the contact point. The outline of the ink flow groove that opens outward in the radial direction of the ballpoint pen tip is traced around the imaginary circle, and the area enclosed by the outline is determined.
In addition, when the ball and the ball holding chamber abut at the boundary between the ball holding chamber and the ink flow hole, the contour of the ink flow groove that opens outward in the radial direction of the ballpoint pen tip is traced of the imaginary circle of maximum diameter that touches each boundary, and the opening projected area of the ink flow groove is determined from the area surrounded by the contour line.
The opening projected area is measured using a microscope VHX-6000 (lens VH-ZST) manufactured by Keyence Corporation, by photographing a front view of the ballpoint pen tip from the front to the rear in the radial direction and horizontally at 200 times magnification, and the opening projected area of the ink flow groove can be measured from the photographed image using the image measurement function.

The ink reservoir tube that contains the ink composition is, for example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, or nylon, or a metal tubular body. The ink reservoir tube may be directly connected to the tip, or the ink reservoir tube and the tip may be connected via a connecting member (tip holder).

The ballpoint pen may have an ink reservoir in the form of a ballpoint pen refill housed in a barrel made of resin, metal, etc., or the barrel itself with the ballpoint pen body attached to the tip may be used as the ink reservoir, with ink filled directly into the barrel.

When the ink reservoir tube is in the form of a ballpoint pen refill, the ballpoint pen refill comprises an ink reservoir tube that contains an ink composition, and a ballpoint pen body that is attached to the ink reservoir tube directly or via a connecting member and that holds the ball rotatably.

In addition, when the ink composition is applied to a retractable ballpoint pen, the structure and shape of the retractable ballpoint pen are not particularly limited, and any structure in which the writing tip provided on the ballpoint pen refill is stored in the barrel while being exposed to the outside air and the writing tip protrudes from the barrel opening by the operation of the retractable mechanism can be used. Examples of the operation method of the retractable mechanism include a knock type, a rotation type, a slide type, etc. An example of the knock type is a configuration in which a knock part is provided at the rear end of the barrel or the side of the barrel, and the writing tip is caused to protrude and retract from the barrel front end opening by pressing the knock part, or a configuration in which the writing tip is caused to protrude and retract from the barrel front end opening by pressing a clip part provided on the barrel. An example of the rotation type is a configuration in which a rotating part is provided at the rear of the barrel, and the writing tip is caused to protrude and retract from the barrel front end opening by rotating the rotating part. The sliding type can be exemplified by a configuration in which a sliding part is provided on the side of the barrel, and the writing tip part is made to protrude and retract from the front end opening of the barrel by operating the slide, or a configuration in which the writing tip part is made to protrude and retract from the front end opening of the barrel by sliding a clip part provided on the barrel. The retractable ballpoint pen may be a composite type retractable ballpoint pen that contains multiple ballpoint pen refills in the barrel, and the writing tip part of one of the ballpoint pen refills protrudes and retracts from the front end opening of the barrel by operating the retractable mechanism.

Figure 3 is a schematic partial cross-sectional view showing an example of a retractable ballpoint pen 1. The retractable ballpoint pen 1 has a ballpoint pen refill 9 housed in a barrel 2 so that it can be retracted. A friction member 10 is disposed at the rear end of the barrel 2. The ballpoint pen refill 9 includes an ink reservoir tube that contains an ink composition, and a ballpoint pen body that is attached to the ink reservoir tube and rotatably holds a ball.

The rear end of the ink composition contained in the ink reservoir tube is filled with an ink backflow preventive body. The ink backflow preventive body is made of a non-volatile liquid or a difficult-to-volatile liquid. Specific examples include petrolatum, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefin, α-olefin oligomer or cooligomer, dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, polyether-modified silicone oil, fatty acid-modified silicone oil, etc., and one type may be used alone or two or more types may be used in combination. It is preferable to add a thickener to at least one of the non-volatile liquid and the difficult-to-volatile liquid to thicken it to a suitable viscosity. Examples of thickeners include silica with a hydrophobic surface, fine silica particles with a methylated surface, aluminum silicate, swellable mica, clay-based thickeners such as hydrophobically treated bentonite and montmorillonite, fatty acid metal soaps such as magnesium stearate, calcium stearate, aluminum stearate, and zinc stearate, tribenzylidene sorbitol, fatty acid amides, amide-modified polyethylene wax, hydrogenated castor oil, dextrin-based compounds such as fatty acid dextrins, and cellulose-based compounds. Furthermore, a liquid ink backflow preventer and a solid ink backflow preventer can be used in combination.

The shape of the ballpoint pen is not limited to the above, but may be a double-ended writing instrument equipped with pen bodies of different shapes or pen bodies that dispense ink compositions of different colors.

The handwriting obtained by writing on a surface using a ballpoint pen containing a reversible thermochromic water-based ink composition can be discolored by a heating or cooling device. Examples of heating devices include an electrical heating and discoloring device equipped with a resistance heating element, a heating and discoloring device filled with hot water, or a hair dryer, but preferably, a friction member is used as a means for discoloring in a simple manner. In other words, the ballpoint pen may further include a friction member.

As the friction member, an elastic body or a viscoelastic body such as an elastomer or a plastic foam, which has a high elasticity and can generate moderate friction and generate frictional heat when rubbed, is suitable. It is also possible to rub the handwriting with an eraser, but since eraser dust is generated during friction, the above-mentioned friction member, which generates almost no eraser dust, is preferably used. As the material for the friction member, silicone resin, SEBS resin (styrene ethylene butadiene styrene block copolymer), polyester resin, alpha-olefin copolymer, etc. are used.

The friction member may be a member (friction body) of any shape that is separate from the writing instrument, and may be combined with the writing instrument to form a writing instrument set; however, providing the friction member on the writing instrument provides excellent portability.
In the case of a writing instrument with a cap, the location where the friction member is provided is not particularly limited, but for example, the cap itself can be formed from a friction member, the barrel itself can be formed from a friction member, if a clip is provided, the clip itself can be formed from a friction member, or a friction member can be provided at the tip (top) of the cap or the rear end of the barrel (the part where the writing tip is not provided).
In the case of a retractable writing instrument, the location where the friction member is provided is not particularly limited. For example, the barrel itself may be made of a friction member, or if a clip is provided, the clip itself may be made of a friction member, or the friction member may be provided near the barrel opening, at the rear end of the barrel (the portion where the writing tip is not provided), or at the knock portion.

Examples of cooling devices include thermochromic devices using a Peltier element, thermochromic devices filled with a refrigerant such as cold water or ice chips, and refrigerators and freezers.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "parts" are based on mass.
The average particle size of the microcapsulated pigment in the present invention is the average particle size (median size) based on volume. In measuring the particle size, an image analysis type particle size distribution measuring software (MacView, manufactured by Mountec Co., Ltd.), a Coulter method (electrical detection zone method) particle size measuring device, a laser diffraction/scattering type particle size distribution measuring device (device name: LA-300, manufactured by Horiba, Ltd.), or the like can be used.
When using a laser diffraction/scattering type particle size distribution analyzer, the measurement is performed using an analyzer that has been calibrated using a standard sample or another analyzer such as the Coulter method (electrical detection zone method).
In the case where the values obtained differ depending on the measuring device, the values obtained using the image analysis-based particle size distribution measuring software take precedence.
In this example, the volume-based average particle size (median size) and particle size were measured using the laser diffraction/scattering type particle size distribution measuring device (device name: LA-300, manufactured by Horiba, Ltd.) calibrated by the Coulter method (electrical detection zone method).

Preparation of Microcapsule Pigment 1 Microcapsule pigment 1 was prepared by encapsulating in microcapsules a reversible thermochromic composition a having color memory, which is composed of 1.0 part of spiro[5H-(1)benzopyrano[2,3-d]pyrimidine-5,1'(3'H)isobenzofuran]-3'-one, 2-(diethylamino)-8-(diethylamino)-4-methyl as an electron donating organic color former, 3.0 parts of 1,1-bis(4-hydroxyphenyl)-2-ethylhexane as an electron accepting compound, 5.0 parts of 2,2-bis(4'-hydroxyphenyl)-hexafluoropropane, and 50.0 parts of 4-benzyloxyphenylethyl caprate as a reaction medium.
The average particle size of the microcapsule pigment 1 was 2.0 μm, the complete decolorization temperature (t4) was 53° C., the complete color development temperature (t1) was −20° C., and the color changed from pink to colorless due to temperature change.

Preparation of Microcapsule Pigment 2 Microcapsule pigment 2 was prepared by encapsulating in microcapsules a reversible thermochromic composition b having color memory, which is composed of an electron-donating color-forming organic compound and 1.0 part of 3,6-bis(diphenylamino)fluoran as a component, 3.0 parts of 1,1-bis(4-hydroxyphenyl)-2-ethylhexane and 5.0 parts of 2,2-bis(4'-hydroxyphenyl)-hexafluoropropane as an electron-accepting compound, and 50.0 parts of 4-benzyloxyphenylethyl caprate as a reaction medium.
The average particle size of the microencapsulated pigment 2 was 1.8 μm, the complete decolorization temperature (t4) was 55° C., the complete color development temperature (t1) was −20° C., and the color changed from blue to colorless due to temperature change.

Preparation of ink compositions No. 1 to 10 were prepared for ballpoint pens having the compositions shown in Table 1 below. The composition values in the table represent mass %, and "-" indicates that no component was added. No. 1 to No. 8 are examples, and No. 9 and No. 10 are comparative examples.

Each component in the table is explained in detail below.
(C) First brilliant pigment 1: LG neo SILVER #325; manufactured by Oike Imaging Co., Ltd.; contains aluminum as a vapor-deposited metal; average particle size 44 μm, average thickness 2 μm
(D) First brilliant pigment 2: LG neo SILVER #500; manufactured by Oike Imaging Co., Ltd.; contains aluminum as a vapor-deposited metal; average particle size: 28 μm, average thickness: 2 μm
(E) Second brilliant pigment 1: Iriodin 103; manufactured by Merck; particle size distribution: 10 μm to 60 μm
(F) Second brilliant pigment 2: Iriodin 123; manufactured by Merck; particle size distribution: 5 μm to 25 μm
(G) Thickener: Xanthan gum; Trade name "Kelzan"; manufactured by Sansho Co., Ltd. (H) Water-soluble organic solvent: Glycerin (I) Sugar: Dextrin; Trade name "Sandec 30"; manufactured by Sanwa Starch Co., Ltd. (J) Surfactant: Phosphate-based surfactant; Trade name "Plysurf AL"; manufactured by Daiichi Kogyo Seiyaku Kogyo Co., Ltd. (K) pH adjuster: Triethanolamine (L) Preservative: (1,2-benzisothiazol-3(2H)-one; Trade name "Proxel XL-2"; manufactured by Lonza Japan Ltd.

Preparation of ballpoint pen tip (see Figures 4 and 5)
A stainless steel wire was cut using a drill or the like to provide a ball holding chamber 913, an ink circulation hole 915 having an inner diameter of 0.42 mm in the center of a bottom wall 914 of the ball holding chamber, and ink circulation grooves 916 extending radially from the ink circulation hole 915. A ball 912 made of cemented carbide and having a diameter of 0.7 mm was placed on the bottom wall, and the tip tip 918 was crimped inward to cause a part of the ball 912 to protrude from the tip tip and to be held in a rotatable manner, thereby obtaining the ballpoint pen tip 91 shown in FIG. 4.
The amount of movement (clearance) of the ball 912 in the ball-point pen tip 91 in the direction of the vertical axis (the axis perpendicular to the radial direction of the ball-point pen tip) was 46 μm.
The ink flow groove 916 had a groove width of 0.15 mm.
Fig. 5 is a cross-sectional view of the ballpoint pen tip of Fig. 4 taken along line A-A, with the ball removed. When the ball 912 is placed on the bottom wall 914 of the ball-holding chamber, the contact between the ball 912 and the bottom wall 914 of the ball-holding chamber is the boundary 919 between the bottom wall 914 of the ball-holding chamber and the ink flow hole 915, and the imaginary circle of maximum diameter that contacts the boundary is a circle formed with the boundary 914 as its circumference, and the projected area of the ink flow groove opening 916A is 0.021 ^mm2 per opening.

Each of the ink compositions obtained was filled into an ink reservoir made of polypropylene resin by suction, and connected to the ballpoint pen tip via a tip holder. Next, an ink backflow prevention body (liquid plug) was filled into the rear end of the ink reservoir, and a tail plug was fitted to the rear of the pipe to obtain a ballpoint pen refill.
When the ink reservoir and the ballpoint pen tip are connected via the tip holder, a coil spring is incorporated in the ballpoint pen tip 91 to bias the ball 912 toward the tip end 918 .

Using the obtained ballpoint pen refill, a retractable ballpoint pen as shown in FIG. 3 was produced. SEBS (styrene ethylene butadiene styrene block copolymer) resin was used for the friction member. The following tests were carried out using the obtained ballpoint pen. The results are shown in the table below.

(Evaluation of handwriting brilliance)
A straight line was written using the ballpoint pen obtained. The glitter of the handwriting was visually observed and evaluated according to the following evaluation criteria. Note that white paper (writing paper A conforming to JIS P3210) and black paper (manufactured by Nagatoya Shoten Co., Ltd., product name: Color Paper B5 medium weight black, thickness 0.09 mm, density 80 g/m2) were used as the medium for the writing test.
The evaluation criteria were A and B as pass, and C as fail.
Evaluation Criteria A: A strong metallic luster was observed throughout the writing.
B: A gentle metallic luster was observed.
C: The metallic luster was weak and problematic in practical use.

(Evaluation of color development and erasability of handwriting)
When the color development of the written marks obtained in the above evaluation and the color erasing when rubbed with a friction member were visually observed, the color development and color erasing of the written marks formed with inks Nos. 1 to 10 were clearly visible.

(Evaluation of temporal stability)
After the ballpoint pen was left for 60 days with the tip facing up, a straight line was written on the medium for the writing test, and the glitter of the writing was visually observed and evaluated according to the following evaluation criteria. The evaluation of stability over time corresponds to the evaluation of pigment dispersion stability. The evaluation criteria were A and B as pass, and C as fail.
Evaluation Criteria A: The luster was good.
B: The initial writing was slightly weak in brilliance, but as writing continued, handwriting with good brilliance was immediately formed. No practical problem.
C: The glitter of the initial writing was weak, and even with continued writing, it took a long time before a writing mark with good glitter could be formed. There was a concern in practical use.

Reference Signs List 1 Retractable ballpoint pen 2 Barrel 21 Slide hole 3 Front shaft 31 Front end hole 4 Intermediate shaft 5 Rear shaft 6 Rotating member 7 Clip body 8 Elastic body 9 Ballpoint pen refill 91 Ballpoint pen tip 911 Tip body 912 Ball 913 Ball holding chamber 914 Ball holding chamber bottom wall 915 Ink flow hole 916 Ink flow groove 916A Ink flow groove opening 917 Rear hole 918 Tip tip 919 Boundary 92 Ink reservoir tube 93 Tail plug 10 Friction member

Claims (3)

A ballpoint pen containing a reversible thermochromic water-based ink composition,
a ball-point pen tip having an ink flow hole provided in the center of a bottom wall of a ball-holding chamber and ink flow grooves extending radially from the ink flow hole, a ball placed on the bottom wall, and a tip end portion of the ball being crimped inwardly so that a part of the ball protrudes from the tip end and is held rotatably, the groove width of the ink flow groove being 0.1 to 0.2 mm;
When the ball of the ballpoint pen tip is placed on the bottom wall of the ball holding chamber, the projected area of the ink flow groove that opens on the outer side in the radial direction of the ballpoint pen tip from the contact part between the ball and the bottom wall of the ball holding chamber formed on the bottom wall of the ball holding chamber is 0.015 to 0.03 mm per opening. ² and
The ink composition includes a reversible thermochromic microencapsulated pigment encapsulating a reversible thermochromic composition comprising an electron donating organic color former, an electron accepting compound, and a reaction medium that determines the temperature at which a color-developing reaction between the electron donating organic color former and the electron accepting compound occurs, a glittering pigment, water, and a thickener, the content of the reversible thermochromic microencapsulated pigment relative to the total content of the glittering pigment is 1 to 100, the content of the glittering pigment is 1 to 7 mass%, and the viscosity measured at 20° C. is 0.1 sec or less. ^-1 7000 to 25000 mPa·s at 1000 sec ^-1 A ballpoint pen having a viscosity of 20 to 30 mPa·s. 2. The ballpoint pen according to claim 1, wherein the ball has a movable amount in the longitudinal direction of the ball of 25 to 60 μm. The ballpoint pen according to claim 1 or 2, further comprising a friction member.

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