JP2016011397A - Ink composition for reversible thermochromic stamp, and stamp containing the ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition for a reversible thermochromic stamp and a stamp containing the ink composition, which satisfy demands for practical use such that a stamp image formed on an important document or the like is visible without decoloring even when the document or the like is left in a high temperature environment such as in a car in summer, and that a stamp image achieves a desired purpose.SOLUTION: The ink composition for a reversible thermochromic stamp comprises the following reversible thermochromic microcapsule pigment, water, and a thickener. The thermochromic microcapsule pigment encapsulates a thermochromic composition and exhibits large hysteresis characteristics relating to a color density-temperature curve and interchangeability between a first hue and a second hue in such a manner that, in a period of temperature elevation in the first hue, the pigment completely changes into the second hue in a temperature range from temperature tand higher; in a period of temperature descent in the second hue state, the pigment starts decoloring from the second hue when the temperature reaches tand completely changes into the first hue in a temperature range from temperature tthat is lower than temperature t, and lower, where temperature tis 15°C or lower and tis 80°C or higher. A stamp 1 containing the above ink composition is also disclosed.

Description

  The present invention relates to a reversible thermochromic stamp ink composition and a stamp incorporating the same.

Conventionally, a reversible thermochromic composition comprising, as a colorant, (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium that determines the temperature at which the color reaction occurs. An ink composition for a reversible thermochromic stamp using the encapsulated reversible thermochromic microcapsule pigment is disclosed (for example, see Patent Document 1).
Even if the printed image formed by the reversible thermochromic stamp ink composition can be decolored by heating, it can be decolored when left in a high temperature environment such as a car in summer, for example. For this reason, the image formed on important documents may be discolored and the intended purpose may not be achieved.

JP 2002-212427 A

  The present invention relates to an ink composition for a reversible thermochromic stamp that can achieve the intended purpose of a printed image without erasing even if the printed image formed on an important document or the like is left in a high temperature environment such as a car in summer. An object and a stamp incorporating it are provided.

In the present invention, (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) an electron transfer reaction by the components (a) and (b) is reversibly caused in a specific temperature range. It contains a reversible thermochromic composition composed of a reaction medium, exhibits a large hysteresis characteristic with respect to the color density-temperature curve, exhibits tautomerism between the first hue and the second hue, and rises in temperature in the first hue. In this process, when the temperature reaches t ₃ , the first hue starts to change color, completely becomes the second hue in the temperature range higher than the temperature t _{3 and} is equal to or higher than the temperature t ₄ , and the temperature drops in the second hue state. in the process, reaches the temperature t _2, the second color begins to discolor, become completely the first color at a lower temperature t ₁ the following temperature range than the temperature t _2, the temperature between the temperature t ₂ and the temperature t ₃ Hysteresis characteristics in which the first hue or the second hue is maintained in the area Are shown, the temperature temperature t ₂ is 15 ℃ below, a reversible thermal discoloration microcapsule pigment is the temperature the temperature t ₄ is equal to or higher than 80 ° C., water and, reversibly thermochromic which comprises a thickener An ink composition for sexual stamp is a requirement.
Furthermore, the ink viscosity measured at 6 rpm using a BL type viscometer at 25 ° C. is 3000 to 10000 mPa · s, and the variability (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) is 1.1. The ink viscosity measured at 6 rpm using a BL type viscometer at 25 ° C. is 3500 to 7000 mPa · s, and the degree of change (ink viscosity measured at 6 rpm / ink measured at 60 rpm) Viscosity) is 1.2 to 2.0, the thickener is an alkali-soluble acrylic emulsion, and the average particle size of the reversibly thermochromic microcapsule pigment is 0.5 to 5.0 μm. It is necessary to be there.
Furthermore, it comprises a printing material having continuous pores, a stamp formed by impregnating the printing material with the ink composition for reversible thermochromic stamp, and an ink reservoir that communicates with the printing material at the rear of the printing material. Require a stamp.

  The present invention is a reversible that satisfies a practical use in which an image formed on an important document can be visually recognized without being discolored even if left in a high temperature environment such as a car in summer, and the image can achieve the intended purpose. An ink composition for a thermochromic stamp and a stamp incorporating the same can be provided.

It is explanatory drawing which shows the discoloration behavior of the microcapsule pigment which included the reversible thermochromic composition. It is a longitudinal cross-sectional explanatory drawing of one Example of the stamp which incorporated the ink composition for reversible thermochromic stamps of this invention. It is a longitudinal cross-sectional explanatory drawing of the other Example of the stamp which incorporated the ink composition for reversible thermochromic stamps of this invention. It is a longitudinal cross-sectional explanatory drawing of the other Example of the stamp which incorporated the ink composition for reversible thermochromic stamps of this invention.

  The ink composition for a reversible thermochromic stamp according to the present invention comprises (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, At least a reversible thermochromic microcapsule pigment containing a reversible thermochromic composition comprising a reaction medium that reversibly occurs in a specific temperature range, water, and a thickener.

(I) an electron donating color-forming organic compound, (b) an electron accepting compound, (c) a reaction medium that reversibly causes an electron transfer reaction by the components (a) and (b) in a specific temperature range; A reversible thermochromic microcapsule pigment in which a reversible thermochromic composition comprising at least one of the following is encapsulated in a microcapsule will be described.
The reversible thermochromic microcapsule pigment exhibits a large hysteresis characteristic, and the shape of the curve plotting the change of the color density due to the temperature change is opposite to the case where the temperature is raised from the lower temperature side than the color change temperature range. The color changes by following a path that differs greatly from when the temperature is lowered from the high temperature side, and the color development state in the low temperature range below the complete color development temperature (t ₁ ), or the high temperature range above the complete decoloration temperature (t ₄ ) The color erasing state is a heat decoloring type having color memory in a specific temperature range [temperature range between t _{2 and} t ₃ (substantially two-phase holding temperature range)]. A reversible thermochromic microcapsule pigment encapsulating a reversible thermochromic composition (which develops color) is used.

The hysteresis characteristic in the color density-temperature curve of the microcapsule pigment encapsulating the reversible thermochromic composition will be described with reference to the graph of FIG.
In FIG. 1, the vertical axis represents color density and the horizontal axis represents temperature. The change in color density due to the temperature change proceeds along the arrow. Here, A is a point indicating a density at a temperature t ₄ (hereinafter referred to as a complete decoloring temperature) reaching a completely decolored state, and B is a temperature t ₃ (hereinafter referred to as a decoloring start temperature) at which decoloring starts. C is a point indicating a density at a temperature t ₂ at which color development starts (hereinafter referred to as a color development start temperature), and D is a temperature t ₁ at which a fully colored state is reached (hereinafter referred to as a color development start temperature). , Referred to as a complete color development temperature).
The length of the line segment EF is a scale indicating the discoloration contrast, and the length of the line segment HG is a temperature width indicating the degree of hysteresis (hereinafter referred to as hysteresis width ΔH). It is easy to maintain each state before and after the color change.
Here, the difference between t ₄ and t ₃ , or the difference between t ₂ and t ₁ (Δt) is a scale indicating the sensitivity of discoloration.

Only one specific state (coloring state) is allowed to exist in the normal temperature range among the color development and decoloring states of the reversible thermochromic composition, and the image formed by the reversible thermochromic composition is generated by heat obtained from a heat eraser or the like. In order to erase the color, the complete color erasing temperature (t ₄ ) is 80 ° C. or higher, and the color development start temperature (t ₂ ) is 15 ° C. or lower.
Here, the color development state can be maintained in a normal temperature range, and the color erasure state is maintained in normal use. Therefore, the complete color erasure temperature (t ₄ ) is 80 ° C. or more and the color development start temperature (t ₂ ). If the heating is stopped in a state where the color disappearance temperature does not reach the complete color erasing temperature (t ₄ ) from the color developing state through the color erasing start temperature (t ₃ ), the state returns to the first state again. And the state in which color development is maintained even if the cooling is stopped in a state where the color development start temperature (t ₂ ) has not reached the complete color development temperature (t ₁ ) from the decolored state. When the complete color erasing temperature (t ₄ ) is 80 ° C. or more exceeding the normal temperature range, the color development state is maintained in a high temperature environment such as a car in summer and the color development start temperature (t ₂ ) is 15 ° C. below the normal temperature range. The decolored state is maintained in normal use at the following temperatures.
Further, if the complete color erasing temperature (t ₄ ) is 90 ° C. or higher, the color development state is more maintained in a high temperature environment, and if the color development start temperature (t ₂ ) is 10 ° C. or lower, the color erasure state is normal. More maintained in use.
Therefore, the temperature setting is an important requirement for selectively displaying a color-changed image on the target surface so that it can be visually recognized, and the image can achieve the intended purpose.
In the above-described temperature setting of the complete color erasing temperature (t ₄ ), it is preferable that the color development state be higher in order to be maintained in a high temperature environment, and the complete color erasing temperature (t ₄ ) is preferably 90 °. It is -200 degreeC, More preferably, it is 100-150 degreeC.
Furthermore, in the temperature setting of the color development start temperature (t ₂ ) described above, it is preferably a lower temperature in order to maintain the decolored state in a normal use state, and −50 to 10 ° C. is preferable. -50-5 degreeC is more suitable.
In order to bring the reversible thermochromic composition into a colored state in advance, it is preferable to cool in a general-purpose freezer as a cooling means, but considering the cooling capacity of the freezer, the limit is up to −50 ° C., Accordingly, the complete color development temperature (t ₁ ) is −50 ° C. or higher.
In the present invention, the hysteresis width (ΔH) is in the range of 70 ° C. to 150 ° C.

Hereinafter, the components (a), (b) and (c) constituting the reversible thermochromic composition will be described.
The component (a), that is, the electron-donating color-forming organic compound is a component that determines the color and is a compound that develops a color by donating electrons to the component (b) that is a developer, and is a phthalide compound, fluoran Examples include compounds, stylinoquinoline compounds, diazarhodamine lactone compounds, pyridine compounds, quinazoline compounds, and bisquinazoline compounds. Examples of the phthalide compound include a diphenylmethane phthalide compound, a phenyl indolyl phthalide compound, an indolyl phthalide compound, a diphenyl methane azaphthalide compound, a phenyl indolyl azaphthalide compound, and derivatives thereof. Examples of the fluorane compound include aminofluorane compounds, alkoxyfluorane compounds, and derivatives thereof.
Examples of these compounds are given below.
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- (N-ethylanilino) phenyl] -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide,
3,6-diphenylaminofluorane,
3,6-dimethoxyfluorane,
3,6-di-n-butoxyfluorane,
2-methyl-6- (N-ethyl-Np-tolylamino) fluorane,
3-chloro-6-cyclohexylaminofluorane,
2-methyl-6-cyclohexylaminofluorane,
2- (2-chloroamino) -6-dibutylaminofluorane,
2- (2-chloroanilino) -6-di-n-butylaminofluorane,
2- (3-trifluoromethylanilino) -6-diethylaminofluorane,
2- (N-methylanilino) -6- (N-ethyl-Np-tolylamino) fluorane,
1,3-dimethyl-6-diethylaminofluorane,
2-chloro-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-di-n-butylaminofluorane,
2-xylidino-3-methyl-6-diethylaminofluorane,
1,2-benz-6-diethylaminofluorane,
1,2-benz-6- (N-ethyl-N-isobutylamino) fluorane,
1,2-benz-6- (N-ethyl-N-isoamylamino) fluorane,
2- (3-methoxy-4-dodecoxystyryl) quinoline,
Spiro [5H- (1) benzopyrano (2,3-d) pyrimidine-5,1 '(3'H) isobenzofuran] -3'-one,
2- (diethylamino) -8- (diethylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1 ′ (3′H) isobenzofuran] -3-one,
2- (Di-n-butylamino) -8- (di-n-butylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1 '(3' H) Isobenzofuran] -3-one,
2- (Di-n-butylamino) -8- (diethylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1 '(3'H) isobenzofuran] -3-one,
2- (Di-n-butylamino) -8- (N-ethyl-Ni-amylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1 ' (3′H) isobenzofuran] -3-one,
2- (Dibutylamino) -8- (dipentylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1 '(3'H) -isobenzofuran] -3 -On,
3- (2-methoxy-4-dimethylaminophenyl) -3- (1-butyl-2-methylindol-3-yl) -4,5,6,7-tetrachlorophthalide,
3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4,5,6,7-tetrachlorophthalide,
3- (2-ethoxy-4-diethylaminophenyl) -3- (1-pentyl-2-methylindol-3-yl) -4,5,6,7-tetrachlorophthalide,
4,5,6,7-Tetrachloro-3- [4- (dimethylamino) -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] xanthen] -3-one,
3 ', 6'-bis [phenyl (3-methylphenyl) amino] -spiro [isobenzofuran-1 (3H), 9'-[9H] xanthen] -3-one,
3 ', 6'-bis [phenyl (3-ethylphenyl) amino] -spiro [isobenzofuran-1 (3H), 9'-[9H] xanthen] -3-one,
4- [2,6-bis (2-ethoxyphenyl) -4-pyridinyl] -N, N-dimethylbenzenamine,
2- (4'-dimethylaminophenyl) -4-methoxy-quinazoline,
4,4 '-(ethylenedioxy) -bis [2- (4-diethylaminophenyl) quinazoline] and the like.
In addition to the above compounds having a substituent on the phenyl group forming the xanthene ring, the fluoranes include a substituent on the phenyl group forming the lactone ring as well as the phenyl group forming the xanthene ring (for example, Or a blue or black compound having an alkyl group such as a methyl group or a halogen atom such as a chloro group.

The component (b), that is, the electron-accepting compound, is a compound that receives electrons from the component (a) and functions as a developer of the component (a), and includes a group of compounds having active protons, a group of pseudo-acidic compounds ( Although it is not an acid, there are a group of compounds that act as an acid in the composition to cause the component (I) to develop color), a group of compounds having electron vacancies, and the like.
Examples of compounds having active protons include monophenols to polyphenols as compounds having phenolic hydroxyl groups, and alkyl groups, aryl groups, acyl groups, alkoxycarbonyl groups, carboxy groups and esters thereof as substituents. Alternatively, those having an amide group, a halogen group, etc., and bis-type and tris-type phenols, phenol-aldehyde condensation resins and the like can be mentioned. Moreover, the metal salt of the compound which has the said phenolic hydroxyl group may be sufficient.

Specific examples are given below.
Phenol, o-cresol, tertiary butylcatechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, n-butyl p-hydroxybenzoate N-octyl p-hydroxybenzoate, resorcin, dodecyl gallate, 2,2-bis (4-hydroxyphenyl) propane, 4,4-dihydroxydiphenylsulfone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4 -Hydroxyphenyl) -3-methylbu 1,1-bis (4-hydroxyphenyl) -2-methylpropane, 1,1-bis (4-hydroxyphenyl) n-hexane, 1,1-bis (4-hydroxyphenyl) n-heptane, , 1-bis (4-hydroxyphenyl) n-octane, 1,1-bis (4-hydroxyphenyl) n-nonane, 1,1-bis (4-hydroxyphenyl) n-decane, 1,1-bis ( 4-hydroxyphenyl) n-dodecane, 1,1-bis (4-hydroxyphenyl) 2-ethylhexane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) ethyl Propionate, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 2,2 Bis (4-hydroxyphenyl) n- heptane, there is 2,2-bis (4-hydroxyphenyl) n- nonane.
The compound having a phenolic hydroxyl group can develop the most effective thermochromic property, but aromatic carboxylic acids and aliphatic carboxylic acids having 2 to 5 carbon atoms, carboxylic acid metal salts, acidic phosphate esters and their It may be a compound selected from metal salts, 1,2,3-triazole and derivatives thereof.

〔式中、Ｒ_１は水素原子又はメチル基を示し、ｍは０〜２の整数を示し、Ｘ_１、Ｘ_２のいずれか一方は−（ＣＨ_２）_ｎＯＣＯＲ_２又は−（ＣＨ_２）_ｎＣＯＯＲ_２、他方は水素原子を示し、ｎは０〜２の整数を示し、Ｒ_２は炭素数４以上のアルキル基又はアルケニル基を示し、Ｙ_１及びＹ_２は水素原子、炭素数１〜４のアルキル基、メトキシ基、又は、ハロゲンを示し、ｒ及びｐは１〜３の整数を示す。〕
前記式（１）で示される化合物のうち、Ｒ_１が水素原子の場合、より広いヒステリシス幅を有する可逆熱変色性組成物が得られるため好適であり、更にＲ_１が水素原子であり、且つ、ｍが０の場合がより好適である。
なお、式（１）で示される化合物のうち、より好ましくは下記一般式（２）で示される化合物が用いられる。

式中のＲは炭素数８以上のアルキル基又はアルケニル基を示すが、好ましくは炭素数１０〜２４のアルキル基、更に好ましくは炭素数１２〜２２のアルキル基である。
前記化合物として具体的には、オクタン酸−４−ベンジルオキシフェニルエチル、ノナン酸−４−ベンジルオキシフェニルエチル、デカン酸−４−ベンジルオキシフェニルエチル、ウンデカン酸−４−ベンジルオキシフェニルエチル、ドデカン酸−４−ベンジルオキシフェニルエチル、トリデカン酸−４−ベンジルオキシフェニルエチル、テトラデカン酸−４−ベンジルオキシフェニルエチル、ペンタデカン酸−４−ベンジルオキシフェニルエチル、ヘキサデカン酸−４−ベンジルオキシフェニルエチル、ヘプタデカン酸−４−ベンジルオキシフェニルエチル、オクタデカン酸−４−ベンジルオキシフェニルエチルを例示できる。 Examples of the (c) component of the reaction medium that causes the electron transfer reaction by the (a) and (b) components to occur reversibly in a specific temperature range include alcohols, esters, ketones, and ethers.
As the component (c), a compound represented by the following general formula (1) can be used.

[Wherein, R ₁ represents a hydrogen atom or a methyl group, m represents an integer of 0 to 2, and _one of X ₁ and X ₂ represents — (CH ₂ ) _n OCOR ₂ or — (CH ₂ ) _n COOR ₂ , the other represents a hydrogen atom, n represents an integer of 0 to 2, R ₂ represents an alkyl or alkenyl group having 4 or more carbon atoms, Y ₁ and Y ₂ represent a hydrogen atom, 1 to 4 carbon atoms An alkyl group, a methoxy group, or halogen, and r and p each represent an integer of 1 to 3. ]
Among the compounds represented by the formula (1), when R ₁ is a hydrogen atom, it is preferable because a reversible thermochromic composition having a wider hysteresis width can be obtained, and R ₁ is a hydrogen atom, and , M is more preferably 0.
Of the compounds represented by the formula (1), a compound represented by the following general formula (2) is more preferably used.

R in the formula represents an alkyl group or alkenyl group having 8 or more carbon atoms, preferably an alkyl group having 10 to 24 carbon atoms, more preferably an alkyl group having 12 to 22 carbon atoms.
Specific examples of the compound include octanoic acid-4-benzyloxyphenylethyl, nonanoic acid-4-benzyloxyphenylethyl, decanoic acid-4-benzyloxyphenylethyl, undecanoic acid-4-benzyloxyphenylethyl, and dodecanoic acid. -4-benzyloxyphenylethyl, tridecanoic acid-4-benzyloxyphenylethyl, tetradecanoic acid-4-benzyloxyphenylethyl, pentadecanoic acid-4-benzyloxyphenylethyl, hexadecanoic acid-4-benzyloxyphenylethyl, heptadecanoic acid Examples thereof include -4-benzyloxyphenylethyl and octadecanoic acid-4-benzyloxyphenylethyl.

（式中、Ｒは炭素数８以上のアルキル基又はアルケニル基を示し、ｍ及びｎはそれぞれ１〜３の整数を示し、Ｘ及びＹはそれぞれ水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、ハロゲンを示す。）
前記化合物として具体的には、オクタン酸１,１−ジフェニルメチル、ノナン酸１,１−ジフェニルメチル、デカン酸１,１−ジフェニルメチル、ウンデカン酸１,１−ジフェニルメチル、ドデカン酸１,１−ジフェニルメチル、トリデカン酸１,１−ジフェニルメチル、テトラデカン酸１,１−ジフェニルメチル、ペンタデカン酸１,１−ジフェニルメチル、ヘキサデカン酸１,１−ジフェニルメチル、ヘプタデカン酸１,１−ジフェニルメチル、オクタデカン酸１,１−ジフェニルメチルを例示できる。 Furthermore, a compound represented by the following general formula (3) can also be used as the component (c).

(In the formula, R represents an alkyl group or alkenyl group having 8 or more carbon atoms, m and n each represents an integer of 1 to 3, X and Y represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, carbon, respectively. (The alkoxy group of Formula 1-4 is shown, and a halogen.)
Specific examples of the compound include 1,1-diphenylmethyl octanoate, 1,1-diphenylmethyl nonanoate, 1,1-diphenylmethyl decanoate, 1,1-diphenylmethyl undecanoate, 1,1-dodecanoic acid 1,1- Diphenylmethyl, tridecanoic acid 1,1-diphenylmethyl, tetradecanoic acid 1,1-diphenylmethyl, pentadecanoic acid 1,1-diphenylmethyl, hexadecanoic acid 1,1-diphenylmethyl, heptadecanoic acid 1,1-diphenylmethyl, octadecanoic acid An example is 1,1-diphenylmethyl.

（式中、Ｘは水素原子、炭素数１乃至４のアルキル基、メトキシ基、ハロゲン原子のいずれかを示し、ｍは１乃至３の整数を示し、ｎは１乃至２０の整数を示す。）
前記化合物としては、マロン酸と２−〔４−(４−クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、こはく酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、こはく酸と２−〔４−(３−メチルベンジルオキシ）フェニル）〕エタノールとのジエステル、グルタル酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、グルタル酸と２−〔４−(４−クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、アジピン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、ピメリン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、スベリン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、スベリン酸と２−〔４−(３−メチルベンジルオキシ）フェニル）〕エタノールとのジエステル、スベリン酸と２−〔４−(４−クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、スベリン酸と２−〔４−(２，４−ジクロロベンジルオキシ）フェニル）〕エタノールとのジエステル、アゼライン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、セバシン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、１，１０−デカンジカルボン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２−〔４−(２−メチルベンジルオキシ）フェニル）〕エタノールとのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (4) can also be used as the component (c).

(Wherein, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, or a halogen atom, m represents an integer of 1 to 3, and n represents an integer of 1 to 20)
Examples of the compound include a diester of malonic acid and 2- [4- (4-chlorobenzyloxy) phenyl)] ethanol, a diester of succinic acid and 2- (4-benzyloxyphenyl) ethanol, succinic acid and 2- Diester with [4- (3-methylbenzyloxy) phenyl)] ethanol, diester with glutaric acid and 2- (4-benzyloxyphenyl) ethanol, glutaric acid and 2- [4- (4-chlorobenzyloxy) Phenyl)] ethanol diester, adipic acid and 2- (4-benzyloxyphenyl) ethanol diester, pimelic acid and 2- (4-benzyloxyphenyl) ethanol diester, suberic acid and 2- (4- Diester with benzyloxyphenyl) ethanol, suberic acid and 2- [4- (3-methyl Benzyloxy) phenyl)] ethanol diester, suberic acid and 2- [4- (4-chlorobenzyloxy) phenyl)] ethanol diester, suberic acid and 2- [4- (2,4-dichlorobenzyloxy) ) Phenyl)] ethanol diester, azelaic acid and 2- (4-benzyloxyphenyl) ethanol diester, sebacic acid and 2- (4-benzyloxyphenyl) ethanol diester, 1,10-decanedicarboxylic acid And 2- (4-benzyloxyphenyl) ethanol diester, 1,18-octadecanedicarboxylic acid and 2- (4-benzyloxyphenyl) ethanol diester, 1,18-octadecanedicarboxylic acid and 2- [4- (2-Methylbenzyloxy) phenyl)] die with ethanol It can be exemplified ether.

（式中、Ｒは炭素数１乃至２１のアルキル基又はアルケニル基を示し、ｎは１乃至３の整数を示す。）
前記化合物としては、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとカプリン酸とのジエステル、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとウンデカン酸とのジエステル、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとラウリン酸とのジエステル、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとミリスチン酸とのジエステル、１，４−ビス（ヒドロキシメトキシ）ベンゼンと酪酸とのジエステル、１，４−ビス（ヒドロキシメトキシ）ベンゼンとイソ吉草酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンと酢酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとプロピオン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンと吉草酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとカプロン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとカプリル酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとカプリン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとラウリン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとミリスチン酸とのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (5) can also be used as the component (c).

(In the formula, R represents an alkyl group or alkenyl group having 1 to 21 carbon atoms, and n represents an integer of 1 to 3).
Examples of the compound include a diester of 1,3-bis (2-hydroxyethoxy) benzene and capric acid, a diester of 1,3-bis (2-hydroxyethoxy) benzene and undecanoic acid, and 1,3-bis (2 -Hydroxyethoxy) benzene and lauric acid diester, 1,3-bis (2-hydroxyethoxy) benzene and myristic acid diester, 1,4-bis (hydroxymethoxy) benzene and butyric acid diester, 1,4 Diesters of bis (hydroxymethoxy) benzene and isovaleric acid, diesters of 1,4-bis (2-hydroxyethoxy) benzene and acetic acid, and 1,4-bis (2-hydroxyethoxy) benzene and propionic acid Diester, diester of 1,4-bis (2-hydroxyethoxy) benzene and valeric acid Diester of 1,4-bis (2-hydroxyethoxy) benzene and caproic acid, diester of 1,4-bis (2-hydroxyethoxy) benzene and caprylic acid, 1,4-bis (2-hydroxyethoxy) benzene And diester of capric acid, 1,4-bis (2-hydroxyethoxy) benzene and lauric acid, and 1,4-bis (2-hydroxyethoxy) benzene and myristic acid.

（式中、Ｘは水素原子、炭素数１乃至４のアルキル基、炭素数１乃至４のアルコキシ基、ハロゲン原子のいずれかを示し、ｍは１乃至３の整数を示し、ｎは１乃至２０の整数を示す。）
前記化合物としては、こはく酸と２−フェノキシエタノールとのジエステル、スベリン酸と２−フェノキシエタノールとのジエステル、セバシン酸と２−フェノキシエタノールとのジエステル、１，１０-デカンジカルボン酸と２−フェノキシエタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２−フェノキシエタノールとのジエステルを例示できる。 Furthermore, a compound represented by the following general formula (6) can also be used as the component (c).

(Wherein, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, m represents an integer of 1 to 3, and n represents 1 to 20) Indicates an integer.)
Examples of the compound 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, An example is a diester of 1,18-octadecanedicarboxylic acid and 2-phenoxyethanol.

（式中、Ｒは炭素数４乃至２２のアルキル基、シクロアルキルアルキル基、シクロアルキル基、炭素数４乃至２２のアルケニル基のいずれかを示し、Ｘは水素原子、炭素数１乃至４のアルキル基、炭素数１乃至４のアルコキシ基、ハロゲン原子のいずれかを示し、ｎは０又は１を示す。）
前記化合物としては、４−フェニル安息香酸デシル、４−フェニル安息香酸ラウリル、４−フェニル安息香酸ミリスチル、４−フェニル安息香酸シクロヘキシルエチル、４−ビフェニル酢酸オクチル、４−ビフェニル酢酸ノニル、４−ビフェニル酢酸デシル、４−ビフェニル酢酸ラウリル、４−ビフェニル酢酸ミリスチル、４−ビフェニル酢酸トリデシル、４−ビフェニル酢酸ペンタデシル、４−ビフェニル酢酸セチル、４−ビフェニル酢酸シクロペンチル、４−ビフェニル酢酸シクロヘキシルメチル、４−ビフェニル酢酸ヘキシル、４−ビフェニル酢酸シクロヘキシルメチルを例示できる。
更に、前記（ハ）成分として下記一般式（８）で示される化合物を用いることもできる。

（式中、Ｒは炭素数３乃至７のアルキル基を示し、Ｘは水素原子、メチル基、ハロゲン原子のいずれかを示し、Ｙは水素原子、メチル基のいずれかを示し、Ｚは水素原子、炭素数１乃至４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を示す。）
前記化合物としては、４−ブトキシ安息香酸フェニルエチル、４−ブトキシ安息香酸フェノキシエチル、４−ペンチルオキシ安息香酸フェノキシエチルを例示できる。 Furthermore, a compound represented by the following general formula (7) can also be used as the component (c).

(In the formula, R represents any 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, and X represents a hydrogen atom and an alkyl having 1 to 4 carbon atoms. A group, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, and n represents 0 or 1.)
Examples of the compound include decyl 4-phenylbenzoate, lauryl 4-phenylbenzoate, myristyl 4-phenylbenzoate, cyclohexylethyl 4-phenylbenzoate, octyl 4-biphenylacetate, nonyl 4-biphenylacetate, 4-biphenylacetic acid Decyl, 4-biphenyl lauryl acetate, 4-biphenyl acetate myristyl, 4-biphenyl acetate tridecyl, 4-biphenyl acetate pentadecyl, 4-biphenyl acetate cetyl, 4-biphenyl acetate cyclopentyl, 4-biphenyl acetate cyclohexyl methyl, 4-biphenyl acetate hexyl And cyclohexylmethyl 4-biphenylacetate.
Furthermore, a compound represented by the following general formula (8) can also be used as the component (c).

(In the formula, R represents an alkyl group having 3 to 7 carbon atoms, X represents a hydrogen atom, a methyl group or a halogen atom, Y represents a hydrogen atom or a methyl group, and Z represents 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 the compound include phenylethyl 4-butoxybenzoate, phenoxyethyl 4-butoxybenzoate, and phenoxyethyl 4-pentyloxybenzoate.

  The blending ratio of the components (a), (b), and (c) depends on the concentration, the color change temperature, the color change form, and the type of each component. In general, the component ratio at which a desired color change characteristic is obtained is (Ii) For component 1, (b) component 0.1-50, preferably 0.5-20, more preferably 2-20, (c) component 1-800, more preferably 5-200. More preferably, it is 10 to 200 (all of the above ratios are parts by mass). Moreover, you may use each component in mixture of 2 or more types, respectively.

The reversible thermochromic composition is encapsulated in a microcapsule wall film and used as a reversible thermochromic microcapsule pigment. This is because the reversible thermochromic composition can be kept in the same composition under the various use conditions and can exhibit the same effects.
Methods for microencapsulating the reversible thermochromic composition include interfacial polymerization, interfacial polycondensation, in situ polymerization, in-liquid curing coating, phase separation from aqueous solution, and phase separation from organic solvent. There are a melt dispersion cooling method, an air suspension coating method, a spray drying method, and the like, which are appropriately selected according to use. Furthermore, a secondary resin film may be provided on the surface of the microcapsule according to the purpose to impart durability, or the surface characteristics may be modified for practical use.
Here, the mass ratio of the reversible thermochromic composition to the microcapsule wall membrane satisfies the range of 7: 1 to 1: 1, preferably 6: 1 to 1: 1.
When the ratio of the reversible thermochromic composition to the wall film is larger than the above range, the thickness of the wall film becomes too thin, and the resistance to pressure and heat tends to decrease, and the ratio of the wall film to the reversible thermochromic composition When the value is larger than the above range, color density and sharpness during color development tend to be reduced.

The reversible thermochromic microcapsule pigment has an average particle diameter of 0.1 to 15 μm, preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, which satisfies the practicality.
When the average particle size exceeds 15 μm, the microcapsule pigment may lack dispersion stability, and when the average particle size is less than 0.1 μm, it is difficult to exhibit high density color development.
When the average particle size is 0.5 to 5.0 μm, the microcapsule pigment can easily enter into the fibers on the paper surface. It is possible to prevent fading.
The particle size is measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by Horiba, Ltd .; LA-300), and the average particle size (median diameter) is calculated on the basis of the numerical value. To do.

The blending ratio of the reversible thermochromic microcapsule pigment is 10 to 40% by mass, preferably 10 to 35% by mass, and more preferably 10 to 30% by mass with respect to the total amount of the ink composition.
If the amount is less than 10% by mass, the color density tends to decrease. If the amount exceeds 40% by mass, the dispersion stability in the ink composition becomes poor.

  The reversible thermochromic microcapsule pigment includes antioxidants, ultraviolet absorbers, infrared absorbers, dissolution aids, antiseptic / antifungal agents, non-thermochromic dyes and pigments as long as they do not affect their functions. Various additives such as can be added.

As the medium, water and, if necessary, a water-soluble organic solvent are used.
Examples of the water-soluble organic solvent include glycols such as glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,3-butylene glycol, ethylene glycol monomethyl ether, and their lower alkyl ethers, 2-pyrrolidone, N- Examples include vinyl pyrrolidone, and glycerin and propylene glycol are preferably used.

Examples of the thickener include xanthan gum, welan gum, succinoglycan (average molecular weight of about 1 to 8 million) whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose, guar gum, locust bean gum and derivatives thereof, hydroxy A thickening polysaccharide having a gelling ability extracted from seaweeds such as ethyl cellulose, alkyl alginate, alkyl ester of methacrylic acid and having a molecular weight of 100,000 to 150,000, glycomannan, agar and carrageenin, Benzylidene sorbitol and benzylidene xylitol or their derivatives, crosslinkable acrylic acid polymer, inorganic fine particles, polyglycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene Nonionic surfactants having an HLB value of 8 to 12, such as castor oil, polyoxyethylene lanolin, lanolin alcohol, beeswax derivative, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, fatty acid amide, Examples thereof include salts of dialkyl or dialkenylsulfosuccinic acid, which can be used alone or in combination.
As the thickener, an alkali-soluble acrylic emulsion is preferably used.
When an alkali-soluble acrylic emulsion is used as the thickener, the pH of the ink composition is adjusted to 6 to 11, preferably 7 to 11, and more preferably 7 to 10.

Further, a binder resin can be added for the purpose of adjusting the stickiness of the printed image and adjusting the viscosity.
The binder resin is selected from a resin emulsion, an alkali-soluble resin, and a water-soluble resin.
Examples of the resin emulsion include polyacrylic acid ester, styrene-acrylic acid copolymer, polyvinyl acetate, ethylene-vinyl acetate copolymer, ethylene-vinyl chloride copolymer, methacrylic acid-maleic acid copolymer, ethylene- Examples include aqueous dispersions such as methacrylic acid copolymers, α-olefin-maleic acid copolymers, polyesters, and polyurethanes. Examples of the alkali-soluble resins include styrene-maleic acid copolymers and ethylene-maleic acid copolymers. Styrene-acrylic acid copolymer, and the like. Examples of the water-soluble resin include polyvinyl alcohol, polyvinyl butyral, and the like, and one or a mixture of two or more can be used.

In addition, additives such as pH adjusters, preservatives, and antifungal agents can be added as necessary.
Examples of the pH adjuster include inorganic basic salts such as ammonia, sodium carbonate, sodium phosphate, sodium hydroxide and sodium acetate, and organic basic compounds such as water-soluble amine compounds such as triethanolamine and diethanolamine.
Examples of the preservative or antifungal agent include carboxylic acid, sodium salt of 1,2-benzisothiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2, 3, 5, 6 -Tetrachloro-4- (methylsulfonyl) pyridine and the like.
In addition, an antifoaming agent such as a fluorine-based surfactant that improves the permeability of the solvent, a nonion, an anion, a cationic surfactant, or dimethylpolysiloxane may be added.
It should be noted that a non-thermochromic dye or pigment is blended in the ink composition so that a thermochromic image exhibiting tautomerism from colored (1) to colored (2) can be formed by temperature change. Can do.

The ink composition has an ink viscosity of 3000 to 10000 mPa · s, preferably 3500 to 7000 mPa · s, more preferably 4000 to 6000 mPa · s, measured at 6 ° C. using a BL type viscometer at 25 ° C. Degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) is 1.1 to 2.5, preferably 1.2 to 2.0, so that a stamp provided with a printing material having continuous pores can be applied. Can meet the application.
When the ink viscosity is less than 3000 mPa · s, the printed image formed on the paper surface using the ink composition tends to spread. If it exceeds 10,000 mPa · s, the fluidity of the microcapsule pigment is insufficient in the continuous pores, and the smooth flow of the ink composition to the printing surface cannot be ensured, and an unclear image is formed by continuous printing operation. .
If the degree of change is less than 1.1, the printed image formed on the paper surface using the ink composition tends to bleed, and if it exceeds 2.5, the microcapsule pigment has insufficient fluidity in the continuous pores. A smooth flow of the ink composition to the ink cannot be ensured, and an unclear image is formed by a continuous printing operation.

The reversible thermochromic stamp ink composition is used as a stamp pad ink composition or a stamp ink composition provided with a printing material having continuous pores.
The stamp pad is impregnated with the stamp pad ink composition to obtain a stamp pad for supplying the ink composition to the stamp surface to be contacted, or the stamp ink composition having a continuous pore has a continuous ink. A stamp is obtained by impregnating a stamp material provided with the stamp material.
A stamp provided with a printing material having continuous pores is formed by impregnating a rubber-like elastic body having continuous pores, which is a printing material, with an ink composition, and when pressed against the target surface, the ink composition is targeted from the opening of the continuous pores. The surface shape of the stamp is transferred. A portion where transfer is not desired is a concave portion, or the opening is closed to prevent the ink composition from adhering to the target surface.
Examples of the surface shape of the stamp include characters such as date and symbol, “confidential”, “CONFIDENTIAL”, “done”, and “received”.
The printing material having continuous pores is stored in the stamp base material so that the printing surface is exposed, and the exposed surface is preferably provided with a cap to prevent the ink composition from being dried or accidentally contacted when not in use.
In addition, the structure which increases the frequency | count of stamping by providing the ink storage part which supplies an ink composition to a printing material in the rear part of the printing material which has a continuous pore may be sufficient.
The stamp material may be impregnated with the ink composition in advance and attached to the stamp, or the stamp material with the stamp material attached thereto may be impregnated with the ink composition.
In the case where the ink composition is impregnated in the stamp material to which the stamp material is attached, the ink composition can be impregnated from the front surface of the printing material, or the ink can be impregnated from the rear surface of the printing material.
Similarly, a stamp having an ink storage part may be pre-filled with ink in the ink storage part, or may be filled with an ink composition in an ink storage part of a stamp provided with a printing material and an ink storage part.

The image formed by the reversible thermochromic stamp ink composition can be discolored by applying a heating color changer or a cool color changer.
Examples of the heating color changing tool include an energization heating color changing tool equipped with a resistance heating element such as a PTC element, a heating color changing tool filled with a medium such as hot water, a heating color changing tool using steam or laser light, and an application of a hair dryer. However, preferably, an energization heating discoloration tool is used.
Examples of the energization heating color changing tool include an energization heating color changing tool using a thermal head, a heat roller, and a hot stamp.
Examples of the cool / heat color changer include energization / cool change color tools using Peltier elements, cool / heat change colors filled with refrigerants such as cold water and ice pieces, refrigerators, freezers, and cold storage materials.

Further, a stamp set is obtained by combining the stamp and an ink composition containing a colorant that is decolored by heating in the shaft cylinder, and a writing tool provided with a pen body at the writing tip is obtained. A stamp set can also be obtained by combining tools.
As the colorant contained in the ink composition of the writing instrument, the same reversible thermochromic microcapsule pigment as described above is used.

  Examples of the ink composition containing a colorant that is decolored by heating include shear-thinning ink containing shear-thinning agent, and cohesiveness obtained by suspending microcapsule pigments in a loosely-aggregated state with a water-soluble polymer flocculant. Ink can be mentioned. Furthermore, an ink in which the specific gravity difference between the microcapsule pigment and the vehicle is adjusted to 0.05 or less can also be mentioned.

By adding the shear thinning agent, it is possible to suppress agglomeration and sedimentation of the microcapsule pigment, and it is possible to suppress bleeding of the handwriting, so that a good handwriting can be formed.
Furthermore, when the writing instrument filled with the ink is in the form of a ballpoint pen, ink leakage from the gap between the ball and the tip when not in use is prevented, or the ink flows backward when the writing tip is left upward (upright state). Can be prevented.
Examples of the shear thinning agent include xanthan gum, welan gum, succinoglycan (average molecular weight of about 1 to 8 million) whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose, guar gum, locust bean gum and the like Derivatives, hydroxyethylcellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000, mainly composed of alkyl esters of methacrylic acid, thickening with gelation ability extracted from seaweeds such as glucomannan, agar and carrageenan Polysaccharides, benzylidene sorbitol and benzylidene xylitol or derivatives thereof, crosslinkable acrylic acid polymer, inorganic fine particles, polyglycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol fatty acid ester, poly Carboxymethyl ethylene alkyl ethers, polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ether, nonionic HLB value, such as fatty acid amide is 8-12 surfactants, salts of dialkyl or dialkenyl sulfosuccinic acid. Examples thereof include a mixture of N-alkyl-2-pyrrolidone and an anionic surfactant, and a mixture of polyvinyl alcohol and an acrylic resin.

Examples of the water-soluble polymer flocculant include polyvinyl pyrrolidone, polyethylene oxide, water-soluble polysaccharides, water-soluble cellulose derivatives and the like. Specific examples of water-soluble polysaccharides include tragacanth gum, guar gum, pullulan, cyclodextrin, and specific examples of water-soluble cellulose derivatives include methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, etc. Can be mentioned.
Any water-soluble polymer flocculant that exhibits a gentle bridging action between pigment particles can be applied to the ink, and among these, a water-soluble cellulose derivative works most effectively.
The polymer flocculant can be blended in an amount of 0.05 to 20% by mass based on the total amount of the ink composition.

Water and, if necessary, a water-soluble organic solvent can be added to the ink.
Examples of the water-soluble organic solvent include ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, 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, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolide And the like can be given.

  In addition, when the ink is filled in a ballpoint pen, a higher fatty acid such as oleic acid, a nonionic surfactant having a long-chain alkyl group, a polyether-modified silicone oil, thiophosphorous acid tri (alkoxycarbonylmethyl ester), Thiophosphorous acid triesters such as thiophosphorous acid tri (alkoxycarbonylethyl ester), phosphoric acid monoester of polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether, polyoxyethylene alkyl ether or phosphorus of polyoxyethylene alkyl aryl ether It is preferable to prevent wear of the ball seat by adding a lubricant such as an acid diester or a metal salt, ammonium salt, amine salt or alkanolamine salt thereof.

In addition, resins such as acrylic resin, styrene maleic acid copolymer, cellulose derivative, polyvinyl pyrrolidone, polyvinyl alcohol, and dextrin can be added as necessary to impart fixing properties and viscosity to the paper surface.
In addition, pH adjusters such as inorganic salts such as sodium carbonate, sodium phosphate and sodium acetate, organic basic compounds such as water-soluble amine compounds, benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, saponin, etc. Rust preventive agent, coalic acid, sodium salt of 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetrachloro-4- (Methylsulfonyl) pyridine and other preservatives or antifungal agents, urea, nonionic surfactants, reduced or non-reduced starch hydrolysates, oligosaccharides such as trehalose, sucrose, cyclodextrin, glucose, dextrin, sorbit, man Knit, Pi Wetting agents such as sodium phosphate, defoamers, dispersing agents, a surfactant may be added a fluorine-based surfactant or a nonionic improve the ink permeability.

A writing instrument is obtained by filling the ink into a marking pen or a ballpoint pen with a marking pen tip or a ballpoint pen tip attached to the tip of the writing.
The structure and shape of the ballpoint pen itself are not particularly limited. For example, the ballpoint pen has an ink storage tube filled with shear-thinning ink in a shaft cylinder, and the ink storage tube communicates with a tip having a ball attached to the tip. In addition, a ballpoint pen in which a liquid stopper for backflow prevention is in close contact with the end face of the ink can be exemplified.
The ballpoint pen tip will be described in more detail. A tip formed by holding a ball in a ball holding portion obtained by pressing and deforming the vicinity of the tip of a metal pipe inward from the outer surface, or a metal material is cut by a drill or the like A chip formed by holding the ball in the ball holding part formed by the above, a chip provided with a resin ball receiving seat inside a metal or plastic chip, or a ball held by the chip is moved forward by a spring body Energized items can be applied.
The ball is 0.3 to 3.0 mm, preferably 0.3 to 1.5 mm, more preferably 0.4 to 1.0 mm, such as cemented carbide, stainless steel, ruby, ceramic, resin, and rubber. A thing of a diameter is applicable.
For example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, or nylon, or a metal is used as the ink storage tube for storing the ink.
In addition to directly connecting the chip to the ink storage tube, the ink storage tube and the chip may be connected via a connecting member (holder).
The ink storage tube may be a refill type in which the refill is accommodated in a shaft cylinder made of resin, metal, or the like. The shaft cylinder may be directly filled with ink.

An ink backflow preventer is filled at the rear end of the ink stored in the ink storage tube.
The ink backflow prevention body composition is composed of a non-volatile liquid or a hardly volatile liquid.
Specifically, petroleum jelly, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefin, α-olefin oligomer or co-oligomer, dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, Examples thereof include polyether-modified silicone oil and fatty acid-modified silicone oil, and one or more can be used in combination.
The non-volatile liquid and / or the hardly volatile liquid is preferably thickened to a suitable viscosity by adding a thickener. As the thickener, the surface is treated with hydrophobic silica, and the surface is methylated. Fine particle silica, aluminum silicate, swellable mica, hydrophobic thickener such as bentonite and montmorillonite, fatty acid metal soap such as magnesium stearate, calcium stearate, aluminum stearate, zinc stearate, tribenzylidene sorbitol, Examples thereof include fatty acid amide, amide-modified polyethylene wax, hydrogenated castor oil, dextrin compounds such as fatty acid dextrin, and cellulose compounds.
Furthermore, the liquid ink backflow prevention body and the solid ink backflow prevention body can be used in combination.

In addition, when filling a marking pen, the structure and shape of the marking pen itself are not particularly limited. For example, a fiber in which an ink occlusion body made of a fiber converging body is built in a shaft cylinder and a capillary gap is formed. A marking pen tip made of a processed body is attached to the shaft cylinder directly or via a connecting member (holder), and the ink occlusion body of the marking pen formed by connecting the ink occlusion body and the tip is impregnated with cohesive ink. An example is a marking pen in which a tip and an ink storage tube are arranged via a marking pen that has been pressed, or a valve element that is opened when the pen tip is pressed, and ink is directly stored in the ink storage tube.
The chip is a porous member having continuous ventilation holes selected from the range of generally 30 to 70% of conventional porosity, such as a resin processed body of fibers, a fusion processed body of heat-meltable fibers, and a felt body. One end is processed into a shape suitable for the purpose such as a bullet shape, a rectangular shape, a chisel shape, etc.
The ink occlusion body is formed by converging crimped fibers in the longitudinal direction, and is configured to be included in a covering body such as a plastic cylinder or a film and to adjust the porosity to a range of approximately 40 to 90%. Is done.
The valve body can be of a general-purpose pumping type, but is preferably set to a spring pressure that can be released by writing pressure.

  Furthermore, the form of the writing instrument is not limited to that described above, and it is a composite writing instrument (a double-headed type or a pen-tip feeding type, etc.) on which a chip with a different form is mounted or a chip for deriving different color inks is mounted. May be.

Examples are shown below, but the present invention is not limited thereto.
In addition, the part in an Example shows a mass part.
Example 1
Production of reversible thermochromic microcapsule pigment A (a) 1 part of 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide as component (B) a component comprising 5 parts of 2,2-bis (4-hydroxyphenyl) hexafluoropropane and (c) a component comprising 50 parts of a diester compound of adipic acid and 2- (4-benzyloxyphenyl) ethanol A reversible thermochromic composition having a memory property is heated and dissolved, and a solution in which 30.0 parts by mass of an aromatic isocyanate prepolymer and 40.0 parts by mass of a co-solvent are mixed as a wall film material in an 8% aqueous polyvinyl alcohol solution. The mixture was emulsified and dispersed, and stirred while warming. Then, 2.5 parts by mass of a water-soluble aliphatic modified amine was added, and further stirring was continued to provide a reversible thermochromic dye. A black capsule suspension was obtained. The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The average particle size of the microcapsule pigment is 2.5 μm, t ₁ : 4 ° C., t ₂ : 14 ° C., t ₃ : 77 ° C., t ₄ : 85 ° C., ΔH: 72 ° C., reversible thermochromic property. Composition: wall film = 2.6: 1.0 The film showed a behavior having hysteresis characteristics and reversibly changed from blue to colorless and from colorless to blue.

Preparation of ink composition for reversible thermochromic stamp 20.0 parts of the above microcapsule pigment A (previously cooled to 4 ° C. or less to develop blue color), 50.0 parts of glycerin, alkali-soluble acrylic emulsion [ Rohm and Haas Japan Co., Ltd., trade name: Primal DR73] 1.5 parts, 0.9 parts triethanolamine, 10.0 parts polyvinylpyrrolidone 50% aqueous solution, 0.2 parts silicone antifoaming agent, permeation A reversible thermochromic stamp ink composition was obtained by mixing 0.5 parts of a leveling agent, 0.2 parts of a preservative, and 16.7 parts of water.
The ink viscosity of the pre-reversible thermochromic stamp ink composition measured at 6 ° C. using a BL type viscometer at 25 ° C. is 4700 mPa · s, and the ink viscosity measured at 60 rpm is 2400 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 1.95. The pH at 25 ° C. was 8.7.

Stamp production (see Fig. 2)
The ink composition was impregnated in the stamping material 2 having continuous pores, fixed to the stamp base material 3 so that the stamping surface of the stamping material was exposed, and the tail plug 4 and the cap 5 were fitted to obtain a stamp.
When the stamp is repeatedly pressed against the target surface (paper), the ink composition smoothly flows out from the stamp surface of the stamp material and moves to the target surface, and a clear image is continuously formed without blurring the image. I was able to.
The image was decolored and colorless when heated using an energization heating discoloration tool equipped with a resistance heating element and a heat roller, and this state could be maintained at room temperature.
In addition, when the paper surface after erasing was placed in a freezer and cooled to a temperature of 4 ° C. or lower, the discoloration behavior in which the printed image turned blue again was exhibited, and the behavior could be reproduced repeatedly.

Example 2
Production of reversible thermochromic microcapsule pigment B (I) 3- (2-Ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide 1 part as component The component (b) comprises 5 parts of 2,2-bis (4-hydroxyphenyl) hexafluoropropane, and the component (c) comprises 50 parts of a diester of 1,4-bis (2-hydroxyethoxy) benzene and caproic acid. A reversible thermochromic composition having color memory is heated and dissolved, and a solution obtained by mixing 30.0 parts by mass of an aromatic isocyanate prepolymer and 40.0 parts by mass of a co-solvent as a wall film material is used as an 8% aqueous polyvinyl alcohol solution. After emulsifying and dispersing in the solution and continuing stirring while warming, 2.5 parts by weight of a water-soluble aliphatic modified amine was added, and further stirring was continued to provide a reversible thermochromic micro A capsule suspension was obtained. The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle size of 2.3 μm, t ₁ : −4 ° C., t ₂ : 4 ° C., t ₃ : 62 ° C., t ₄ : 82 ° C., ΔH: 72 ° C., reversible thermal discoloration. Composition: wall film = 2.6: 1.0 A behavior having a hysteresis characteristic was exhibited, and the color changed reversibly from blue to colorless and from colorless to blue.

Preparation of ink composition for reversible thermochromic stamp 18.0 parts of the microcapsule pigment B (previously cooled to −4 ° C. or less to develop blue color), 50.0 parts of glycerin, alkali-soluble acrylic emulsion [Rohm and Haas Japan Co., Ltd., trade name: Primal TT935] 3.3 parts, 0.9 parts of triethanolamine, 10.0 parts of a 50% aqueous solution of polyvinylpyrrolidone, 0.2 parts of a silicon-based antifoaming agent, A reversible thermochromic stamp ink composition was obtained by mixing 0.5 part of a permeation leveling agent, 0.2 part of a preservative, and 16.9 parts of water.
The ink viscosity of the pre-reversible thermochromic stamp ink composition measured at 6 rpm using a BL-type viscometer at 25 ° C. is 4000 mPa · s, and the ink viscosity measured at 60 rpm is 3000 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 1.33. The pH at 25 ° C. was 8.0.

Stamp production (see Fig. 3)
The ink composition is impregnated into the printing material 2 having continuous pores and the storage unit 6 having continuous pores with a porosity higher than that of the printing material, and the storage unit 6 is accommodated in the stamp base material 3 and comes into contact with the storage unit The stamp 3 was fitted together, and the tail plug 4 and the cap 5 were fitted to obtain a stamp.
When the stamp is repeatedly pressed against the target surface (paper), the ink composition smoothly flows out of the stamp surface of the stamp material and moves to the target surface, so that a clear image is formed more continuously without bleeding. We were able to.
The image was decolored and colorless when heated using an energization heating discoloration tool equipped with a resistance heating element and a heat roller, and this state could be maintained at room temperature.
In addition, when the paper surface after erasing was placed in a freezer and cooled to a temperature of −4 ° C. or lower, the discoloration behavior in which the printed image turned blue again was exhibited, and the behavior could be reproduced repeatedly.

Example 3
Production of reversible thermochromic microcapsule pigment C (I) 2-part (2-chloroanilino) -6-di-n-butylaminofluorane as component 1 and 2,2-bis (4-hydroxy) as component (B) Phenyl) hexafluoropropane 3 parts, 1,1-bis (4-hydroxyphenyl) -n-decane 3 parts, (ha) Diester 50 of 1,4-bis (2-hydroxyethoxy) benzene and caproic acid as component 8% of a solution in which a reversible thermochromic composition having color memory property composed of parts is heated and dissolved, and 30.0 parts by mass of an aromatic isocyanate prepolymer and 40.0 parts by mass of a co-solvent are mixed as a wall film material. After emulsifying and dispersing in an aqueous polyvinyl alcohol solution and continuing stirring while warming, 2.5 parts by weight of a water-soluble aliphatic modified amine was added, and stirring was further continued to achieve reversible thermochromic micro A capsule suspension was obtained. The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The average particle diameter of the microcapsule pigment is 1.8 μm, t ₁ : −7 ° C., t ₂ : 1 ° C., t ₃ : 58 ° C., t ₄ : 80 ° C., ΔH: 72 ° C., reversible thermal discoloration. Composition: wall film = 2.6: 1.0 A behavior having a hysteresis characteristic was exhibited, and the color changed reversibly from pink to colorless and from colorless to pink.

Preparation of ink composition for reversible thermochromic stamp The microcapsule pigment C (previously cooled to -7 ° C. or lower and colored pink) 16.0 parts, glycerin 50.0 parts, alkali-soluble acrylic Emulsions [Rohm and Haas Japan Co., Ltd., trade name: Primal TT935] 4.4 parts, 0.9 parts of triethanolamine, 10.0 parts of a 50% aqueous solution of polyvinylpyrrolidone, 0.2 parts of a silicon-based antifoaming agent A reversible thermochromic stamp ink composition was obtained by mixing 0.5 part of a permeation leveling agent, 0.2 part of a preservative and 17.8 parts of water.
The ink viscosity of the pre-reversible thermochromic stamp ink composition measured at 6 rpm using a BL type viscometer at 25 ° C. is 8000 mPa · s, and the ink viscosity measured at 60 rpm is 6600 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 1.21. The pH at 25 ° C. was 7.6.

Stamp production (see Fig. 4)
The ink composition is impregnated in the printing material 2 having continuous pores and the storage unit 6 having continuous pores having a porosity higher than that of the printing material, and the storage unit is accommodated in the replacement unit 7 and brought into contact with the storage unit. Then, the stamp material was fixed, the replacement part and the stamp base material 3 were screwed together, and the tail plug 4 and the cap 5 were fitted to obtain a stamp.
When the stamp is repeatedly pressed against the target surface (paper), the ink composition smoothly flows out of the stamp surface of the stamp material and moves to the target surface, so that a clear image is formed more continuously without bleeding. We were able to.
The image was decolored and colorless when heated using an energization heating discoloration tool equipped with a resistance heating element and a heat roller, and this state could be maintained at room temperature.
In addition, when the paper surface after erasing was put into a freezer and cooled to a temperature of −7 ° C. or lower, the discoloration behavior that the pink image became pink again was exhibited, and the behavior could be reproduced repeatedly.
Further, the stamp could be put to practical use by removing the replacement unit from the stamp base material and mounting a plurality of other replacement units.
Another replacement part contains the same ink, a replacement part with the same printing material, a different color ink, a replacement part with the same printing material, the same ink, and different A replacement part provided with an image printing material and a replacement part containing different color inks were prepared.

Example 4
Production of reversible thermochromic microcapsule pigment D (I) 3- (2-Ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide 1 part as component Reversible thermal discoloration having color memory consisting of 5 parts 2,2-bis (4-hydroxyphenyl) hexafluoropropane as component (b) and 50 parts diester compound of succinic acid and 2-phenoxyethanol as component c The aqueous composition is dissolved by heating, and a solution prepared by mixing 30.0 parts by mass of an aromatic isocyanate prepolymer and 40.0 parts by mass of a co-solvent as a wall film material is emulsified and dispersed in an aqueous 8% polyvinyl alcohol solution, followed by heating. After stirring, 2.5 parts by weight of water-soluble aliphatic modified amine was added, and stirring was further continued to obtain a reversible thermochromic microcapsule suspension. It was. The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The average particle diameter of the microcapsule pigment is 2.5 μm, t ₁ : 6 ° C., t ₂ : 8 ° C., t ₃ : 92 ° C., t ₄ : 106 ° C., ΔH: 92 ° C., reversible thermochromic property. Composition: wall film = 2.6: 1.0 The film showed a behavior having hysteresis characteristics and reversibly changed from blue to colorless and from colorless to blue.

Preparation of ink composition for reversible thermochromic stamp 20.0 parts of the above microcapsule pigment D (previously cooled to 6 ° C. or less and colored blue) 50.0 parts of glycerin, alkali-soluble acrylic emulsion [ Rohm and Haas Japan Co., Ltd., trade name: Primal TT935] 1.6 parts, alkali-soluble acrylic emulsion [Rohm and Haas Japan Co., Ltd., trade name: Primal DR73] 0.8 parts, Tri 0.9 parts of ethanolamine, 10.0 parts of polyvinylpyrrolidone 50% aqueous solution, 0.2 parts of silicon-based antifoaming agent, 0.5 part of permeation leveling agent, 0.2 part of preservative, 15.8 parts of water By mixing, an ink composition for a reversible thermochromic stamp was obtained.
The ink viscosity of the pre-reversible thermochromic stamp ink composition measured at 6 ° C. using a BL-type viscometer at 25 ° C. is 5500 mPa · s, and the ink viscosity measured at 60 rpm is 3550 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 1.55. The pH at 25 ° C. was 8.3.

Preparation of Stamp The ink composition was impregnated into a stamp material having continuous pores, fixed to a stamp substrate so that the stamp surface of the stamp material was exposed, and a tail plug and a cap were fitted to obtain a stamp.
When the stamp is repeatedly pressed against the target surface (paper), the ink composition smoothly flows out from the stamp surface of the stamp material and moves to the target surface, and a clear image is continuously formed without blurring the image. I was able to.
The image was decolored and colorless when heated using an energization heating discoloration tool equipped with a resistance heating element and a heat roller, and this state could be maintained at room temperature.
In addition, when the paper surface after erasing was placed in a freezer and cooled to a temperature of 6 ° C. or lower, the discoloration behavior in which the printed image turned blue again was exhibited, and the behavior could be reproduced repeatedly.

Example 5
Preparation of ink composition for reversible thermochromic stamp 18.0 parts of the above microcapsule pigment D (previously cooled to 6 ° C. or less to develop a blue color), 50.0 parts of glycerin, alkali-soluble acrylic emulsion [ Rohm and Haas Japan Co., Ltd., trade name: Primal TT935] 5.5 parts, 0.9 parts of triethanolamine, 10.0 parts of a 50% aqueous solution of polyvinyl pyrrolidone, 0.2 parts of a silicone-based antifoaming agent, permeation A reversible thermochromic stamp ink composition was obtained by mixing 0.5 parts of a leveling agent, 0.2 parts of a preservative, and 14.7 parts of water.
The ink viscosity of the reversible thermochromic stamp ink composition measured at 6 rpm using a BL type viscometer at 25 ° C. is 10000 mPa · s, and the ink viscosity measured at 60 rpm is 9000 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 1.11. The pH at 25 ° C. was 7.2.

Preparation of stamp The ink composition is impregnated into a printing material having continuous pores and a storage part having continuous pores with a porosity higher than that of the printing material, and the storage part is accommodated and brought into contact with the storage part to fix the printing material. A stamp base, a sheath disposed on the outer periphery of the stamp base so as to be slidable with respect to the stamp base, and when not in use, a sheath having a lower end positioned below the stamp surface of the stamp by resilience, and a sheath A stamp having a pair of shutter members arranged in the section and shielding the printing material when not in use was obtained.
When the stamp is repeatedly pressed against the target surface (paper), the ink composition smoothly flows out of the stamp surface of the stamp material and moves to the target surface, so that a clear image is formed more continuously without bleeding. We were able to.
The image was decolored and colorless when heated using an energization heating discoloration tool equipped with a resistance heating element and a heat roller, and this state could be maintained at room temperature.
In addition, when the paper surface after erasing was placed in a freezer and cooled to a temperature of 6 ° C. or lower, the discoloration behavior in which the printed image turned blue again was exhibited, and the behavior could be reproduced repeatedly.

Example 6
Preparation of ink composition for reversible thermochromic stamp 25.0 parts of microcapsule pigment D prepared in Example 5 (previously cooled to 6 ° C. or less to develop blue color), 50.0 parts of glycerin, alkali acceptable Soluble acrylic emulsion [Rohm and Haas Japan Ltd., trade name: Primal DR73] 1.1 parts, 0.9 parts triethanolamine, 10.0 parts polyvinylpyrrolidone 50% aqueous solution, silicon-based antifoaming agent 0 2 parts, 0.5 part of a permeation leveling agent, 0.2 part of a preservative, and 12.1 parts of water were mixed to obtain an ink composition for a reversible thermochromic stamp.
The ink viscosity of the pre-reversible thermochromic stamp ink composition measured at 6 rpm with a BL-type viscometer at 25 ° C. is 3000 mPa · s, and the ink viscosity measured at 60 rpm is 1500 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 2.0. The pH at 25 ° C. was 8.9.

Preparation of Stamp The ink composition was impregnated into a belt-shaped printing material for rotary stamping having continuous pores on which a marking surface consisting of numbers from 0 to 9 was formed.
The stamp was obtained by incorporating the stamp into a rotary stamp.
When the stamp is repeatedly pressed against the target surface (paper), the ink composition smoothly flows out of the stamp surface of the stamp material and moves to the target surface, so that a clear image is formed more continuously without bleeding. We were able to.
The image was decolored and colorless when heated using an energization heating discoloration tool equipped with a resistance heating element and a heat roller, and this state could be maintained at room temperature.
In addition, when the paper surface after erasing was placed in a freezer and cooled to a temperature of 6 ° C. or lower, the discoloration behavior in which the printed image turned blue again was exhibited, and the behavior could be reproduced repeatedly.

Example 7
Preparation of Stamp The ink composition prepared in Example 4 was impregnated into a printing material having continuous pores, fixed to the stamp base material so that the printing surface of the printing material was exposed, and a tail plug and a cap were fitted to obtain a stamp.
In addition, a guide piece that moves up and down by a spring mechanism in the vertical direction at the time of stamping is provided around the printing material so that the printing material contacts the symmetrical surface evenly by contacting the symmetrical surface (paper). Consists of.

Production of reversible thermochromic microcapsule pigment E (I) As component (A) As component (3- (4-Diethylamino-2-hexyloxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) 2.0 parts of -4-azaphthalide, 4.0 parts of 1,1-bis (4′-hydroxyphenyl) hexafluoropropane as component (b), 1,1-bis (4′-hydroxyphenyl) n-decane 4 0.0 part, reversible thermochromic composition having color memory composed of 50.0 parts of capric acid-4-benzyloxyphenylethyl as component (c) is dissolved by heating, and an aromatic isocyanate prepolymer as a wall film material A solution prepared by mixing 30.0 parts and 40.0 parts of a co-solvent was emulsified and dispersed in an 8% aqueous polyvinyl alcohol solution, and stirred while heating. 2.5 parts of min was added and stirring was continued to obtain a reversible thermochromic microcapsule suspension. The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle size of 2.0 μm, t ₁ : −14 ° C., t ₂ : −6 ° C., t ₃ : 48 ° C., t ₄ : 62 ° C., ΔH: 65 ° C., reversible heat. Color-changing composition: wall film = 2.6: A behavior having a hysteresis characteristic of 1.0 was exhibited, and the color changed reversibly from blue to colorless and from colorless to blue.

Preparation of writing instrument 25.7 parts of the reversible thermochromic microcapsule pigment E (previously cooled to -14 ° C. or less to develop blue color), 0.2 part of succinoglycan (shear thinning agent), urea 5.5 parts, 7.5 parts of glycerin, 0.2 parts of modified silicone antifoaming agent, 0.1 part of antifungal agent, 1.0 part of lubricant, 1.0 part of triethanolamine, 58.8 parts of water Were mixed to prepare a reversible thermochromic water-based ink composition.
The ink composition was sucked and filled into a polypropylene pipe having an inner diameter of 4.4 mm, and connected to a ballpoint pen tip via a resin holder.
Next, a viscoelastic ink backflow prevention body (liquid stopper) mainly composed of polybutene is filled from the rear part of the polypropylene pipe, and a tail plug is fitted to the rear part of the pipe. After the cylinder was assembled and the cap was fitted, a deaeration process was performed by centrifugation to obtain a writing instrument (ballpoint pen).
The ballpoint pen tip has a stainless steel ball having a diameter of 0.5 mm held at the tip of the tip formed by cutting a metal to form a ball receiving seat and an ink outlet portion, and the ball is a spring body. Thus, a SEBS friction member is fixed to the rear barrel as a friction body at the rear part.

A stamp set was obtained by combining the stamp and the writing instrument.
On the paper surface, blue letters (handwriting) were written using the writing instrument, and then a printed image was formed using the stamp.
The handwriting and the printed image were discolored and became colorless when heated using an electric heating color changing tool equipped with a resistance heating element and a heat roller, and this state could be maintained at room temperature.
In addition, when the paper surface after erasing was put in a freezer and cooled to a temperature of −14 ° C. or lower, handwriting and an image appeared again, and the behavior could be reproduced repeatedly.
Next, a character (handwriting) is written on the paper surface using the writing instrument, and then an image is formed using the stamp and is rubbed using a friction member provided on the writing instrument. Although it was erased by heat, the printed image was slightly erased by frictional heat, but since it did not reach the complete decolorization temperature, it was restored immediately and it was possible to determine the authenticity from its discoloration behavior.

Comparative Example 1
Preparation of ink composition for reversible thermochromic stamp 25.0 parts of microcapsule pigment D produced in Example 4 (previously cooled to 6 ° C. or less to develop blue color), 50.0 parts of glycerin, xanthan gum 0 .5 parts, triethanolamine 0.5 parts, polyvinylpyrrolidone 50% aqueous solution 10.0 parts, silicon-based antifoaming agent 0.2 parts, permeation leveling agent 0.5 parts, preservative 0.2 parts, water 13.1 parts were mixed to obtain a reversible thermochromic stamp ink composition.
The ink viscosity of the pre-reversible thermochromic stamp ink composition measured at 6 rpm using a BL-type viscometer at 25 ° C. is 10500 mPa · s, and the ink viscosity measured at 60 rpm is 1750 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 6.0.

Preparation of Stamp The ink composition was impregnated into a stamp material having continuous pores, fixed to a stamp substrate so that the stamp surface of the stamp material was exposed, and a tail plug and a cap were fitted to obtain a stamp.
When the stamp was pressed against the target surface (paper), the ink was not supplied to the printing surface in a uniform state, so the initial printed image was non-uniform and a clear image could not be formed.
Furthermore, since the ink composition does not flow out smoothly when continuously imprinted, a clear image cannot be formed continuously, and the image gradually fades with each imprint, resulting in an unclear image. Been formed.

Comparative Example 2
Preparation of ink composition for reversible thermochromic stamp 25.0 parts of microcapsule pigment D prepared in Example 4 (previously cooled to 6 ° C. or less and colored blue) 50.0 parts of glycerin, sodium alginate 0.2 parts, 0.5 parts triethanolamine, 10.0 parts polyvinylpyrrolidone 50% aqueous solution, 0.2 parts silicon antifoaming agent, 0.5 parts penetration leveling agent, 0.2 parts preservative, 13.4 parts of water was mixed to obtain a reversible thermochromic stamp ink composition.
The ink viscosity of the pre-reversible thermochromic stamp ink composition measured at 6 rpm using a BL-type viscometer at 25 ° C. is 1300 mPa · s, and the ink viscosity measured at 60 rpm is 920 mPa · s. The degree (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) was 1.41.

Preparation of Stamp The ink composition was impregnated into a stamp material having continuous pores, fixed to a stamp substrate so that the stamp surface of the stamp material was exposed, and a tail plug and a cap were fitted to obtain a stamp.
When the stamp is repeatedly pressed against the target surface (paper), the ink composition moves from the stamp surface to the target surface to form a print image, but the initial print image is blurred and blurred due to excessive ink ejection. As a result, a clear image could not be formed.
Further, with the stamp, the microcapsule pigment in the ink composition settled with time, and it was impossible to form a print image.

t ₁ Complete color development temperature of microcapsule pigment encapsulating reversible thermochromic composition t ₂ Color development start temperature of microcapsule pigment encapsulating reversible thermochromic composition t ₃ Microcapsule pigment encapsulating reversible thermochromic composition Decolorization start temperature t ₄ Complete decolorization temperature of microcapsule pigment encapsulating reversible thermochromic composition ΔH Hysteresis width 1 Stamp 2 Printing material 3 Stamp base material 4 Tail plug 5 Cap 6 Ink storage section 7 Replacement section

Claims (7)

(B) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium that reversibly causes an electron-donating reaction by the components (a) and (b) above in a specific temperature range. In the process of enveloping the reversible thermochromic composition, exhibiting a large hysteresis characteristic with respect to the color density-temperature curve, exhibiting tautomerism between the first hue and the second hue, and in the process of increasing the temperature in the first hue, Upon reaching the temperature t _3, the first color begins to discolor, become completely second color at higher temperatures t ₄ above temperature range than the temperature t _3, in the process of temperature in the second color state is lowered, the temperature Upon reaching t _2, the second color begins to discolor, become completely the first color at a lower temperature t ₁ the following temperature range than the temperature t _2, the temperature range between the temperature t ₂ and the temperature t ₃ 1 The hysteresis characteristic that the hue or the second hue is maintained is shown. Degrees t ₂ is at a temperature of 15 ℃ or less, and a reversible thermochromic microcapsule pigment is the temperature the temperature t ₄ is equal to or higher than 80 ° C., water and, for reversible thermochromic stamp comprising a thickener Ink composition.   The ink viscosity measured at 6 rpm using a BL type viscometer at 25 ° C. is 3000 to 10000 mPa · s, and the degree of change (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) is 1.1 to 2. The reversible thermochromic stamp ink composition according to claim 1, which is 5.   The ink viscosity measured at 6 rpm using a BL type viscometer at 25 ° C. is 3500 to 7000 mPa · s, and the degree of change (ink viscosity measured at 6 rpm / ink viscosity measured at 60 rpm) is 1.2 to 2 The reversibly thermochromic stamp ink composition according to claim 2, which is 0.0.   The ink composition for a reversible thermochromic stamp according to any one of claims 1 to 3, wherein the thickener is an alkali-soluble acrylic emulsion.   The ink composition for reversible thermochromic stamp according to any one of claims 1 to 4, wherein the reversibly thermochromic microcapsule pigment has an average particle size of 0.5 to 5.0 µm.   A stamp comprising a printing material having continuous pores, the printing material being impregnated with the ink composition for a reversible thermochromic stamp according to any one of claims 1 to 5.   The stamp according to claim 6, wherein an ink storage portion communicating with the printing material is provided at a rear portion of the printing material.

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