JP2009197043A - Color-changeable ink composition for writing utensil, writing utensil and set thereof containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color-changeable ink composition for writing utensil, that forms an arbitrary handwriting by writing, exhibits rich color change variation in which the handwriting changes its colors in different color tones caused by heating or cooling or by application of discoloration liquid, and is high in commercial value, and to provide a writing utensil and a writing utensil unit containing the ink composition. <P>SOLUTION: The color-changeable ink composition for a writing utensil comprises water, a micro-encapsulated pigment filled with a reversible thermochromic composition as a coloring agent comprised of (a) an electron donating colorative organic compound, (b) an electron accepting compound, and (c) a reaction medium that controls color reaction of the (a) and (b), and a dye that changes or loses color by a reducing agent. The writing utensil is filled with the ink composition, and the writing utensil set comprises the writing utensil and a friction matter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink composition for a color-changing writing instrument, a writing instrument containing the ink composition, and a writing instrument set. More specifically, the present invention relates to an ink composition for a color-changing writing instrument that can form handwriting of various colors by application of a temperature change and a color-changing liquid, a writing instrument that contains the ink composition, and a writing instrument set.

Conventionally, as an ink composition capable of forming a handwriting that changes color, an ink composition using a dye that changes color or decolors with a reducing agent as a colorant (for example, see Patent Document 1), an ink using a reversible thermochromic material A composition (see, for example, Patent Document 2) is disclosed.
The handwriting formed by a writing instrument incorporating the ink composition can be discolored or decolored by applying a color changing solution containing a reducing agent, or by heating or cooling, but the handwriting is colored. No color, or only two states from colored to different colors are visually recognized, and it was not possible to form more multicolored handwriting.
In order to solve the above-mentioned problems, it is conceivable to prepare an ink composition containing a reversible thermochromic material having a different color change temperature. However, temperature control in the color change process is difficult, and the practicality is not always satisfied. .
Japanese Patent Publication No.54-22345 JP-A-1-54081

  The present invention is to provide an ink composition for a color-changing writing instrument capable of easily changing the handwriting to various colors by applying a temperature change and a color-changing liquid, a writing instrument containing the ink composition, and a writing instrument set. is there.

The present invention controls water, (b) an electron-donating color-forming organic compound as a colorant, (b) an electron-accepting compound, and (c) the color reaction of (a) and (b) above. A microcapsule pigment containing a reversible thermochromic composition comprising a reaction medium, and an ink composition for a color-changing writing instrument containing a dye that changes color or decolors with a reducing agent are required.
Furthermore, the microcapsule pigment exhibits a large hysteresis characteristic with respect to the color density-temperature curve and exhibits tautomerism between the colored state and the colorless state, and the pigment reaches the temperature t ₃ in the process of increasing the temperature from the colored state. Then, the color starts to disappear and becomes completely colorless in a temperature range higher than the temperature t ₃ and higher than the temperature t ₄ , and in the process of decreasing the temperature from the colorless state, the color begins to be colored when the temperature t ₂ lower than the temperature t ₃ is reached, A hysteresis characteristic that is completely colored in a temperature range lower than the temperature t ₂ and lower than the temperature t ₁ , and is selectively maintained in a colored state or a colorless state in the temperature range between the temperature t ₂ and the temperature t ₃ ; The temperature t ₁ is in the range of −30 to 0 ° C., the temperature t ₄ is in the range of 45 to 95 ° C., and contains a non-discoloring colorant.
Furthermore, a writing instrument containing the ink composition for a color-changing writing instrument is required.
Further, the rear end portion of the writing instrument is provided with a color-changing applicator containing a color-changing liquid, a friction member is provided, a cap is provided, and the cap is provided with a friction member, etc. Is a requirement.
Furthermore, a writing instrument set including the writing instrument and a friction body is a requirement.

  The present invention forms an arbitrary handwriting by writing, and the handwriting is rich in variations of color change that changes color to different colors by heating or cooling or application of a color changing liquid, and has a high commercial value ink composition for a color-changing writing instrument Objects, writing instruments that contain them, and writing instrument sets can be provided.

The ink composition for a color-changing writing instrument controls (i) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) the color reaction of (a) and (b). A reversible thermochromic microcapsule pigment encapsulating at least a reversible thermochromic composition comprising a reaction medium is used as a colorant.
Examples of the reversible thermochromic microcapsule pigment include a predetermined temperature (discoloration point) described in JP-B-51-44706, JP-B-51-44707, JP-B-1-29398, and the like. Before and after the color change, the color disappears in the temperature range above the high temperature side discoloration point, and the color develops in the temperature range below the low temperature side discoloration point. The other state is maintained while the heat or cold required to develop the state is applied, but when the heat or cold is no longer applied, the hysteresis width returns to the state exhibited in the normal temperature range. Can be applied to a microcapsule pigment encapsulating a reversible thermochromic composition having relatively small characteristics (ΔH = 1 to 7 ° C.) (see FIG. 1).

In addition, large hysteresis characteristics (ΔH _B = 8 to 50 ° C.) described in JP- _B -4-17154, JP-A-7-179777, JP-A-7-33997, JP-A-8-39936, and the like. ), That is, when the shape of the curve plotting the change in the color density due to the temperature change is lowering the temperature from the lower temperature side than the color changing temperature range, as opposed to increasing the temperature from the lower temperature side. In the specific temperature range, the color changes in a low temperature range below the complete color development temperature (t ₁ ) or the color erase state in the high temperature range above the complete color erase temperature (t ₄ ). A microcapsule pigment containing a reversible thermochromic composition having color memory in a temperature range between t _{2 and} t ₃ (substantially two-phase holding temperature range) can also be applied (see FIG. 2).

The hysteresis characteristic in the color density-temperature curve of the reversible thermochromic composition will be described.
In FIG. 2, 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) that reaches a completely decolored state, and B is a temperature t ₃ (hereinafter referred to as a decoloring start temperature). 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 complete color development state is reached (hereinafter referred to as a complete color development state). This is a point indicating a density at a color development temperature).
Discoloration temperature region is a temperature range between the t ₁ and t _4, both states of the colored state and the decolored state can coexist, a temperature range of between t ₂ and t ₃ is a region having a large difference in color density It is a real discoloration temperature range.
The length of the line segment EF is a scale indicating the discoloration contrast, and the length of the line segment HG passing through the midpoint of the line segment EF is a temperature width indicating the degree of hysteresis (hereinafter referred to as hysteresis width ΔH). If this ΔH value is small, only one specific state can exist in the normal temperature range among both states before and after the color change. Further, when the ΔH value is large, it is easy to maintain each state before and after the color change.

Specifically, as the reversible thermochromic composition having color memory, a complete color development temperature t ₁ is a temperature that can be obtained only in a freezing room, a cold district, etc., that is, −30 to 0 ° C., preferably −30 to − 10 ° C. and the temperature at which the complete decoloring temperature t ₄ is obtained from a frictional heat generated by a friction body, a heating body such as a hair dryer, that is, 45 to 95 ° C., preferably 50 to 90 ° C., more preferably 60 to 80 ° C. By specifying the ΔH value in the range of 40 to 60 ° C., it is possible to effectively function to maintain the color exhibited in the normal state (daily life temperature range).

Specific examples of the compounds (a), (b) and (c) are shown below.
As the component (a) of the present invention, that is, the electron-donating color-forming organic compound, diphenylmethane phthalides, phenyl indolyl phthalides, indolyl phthalides, diphenyl methane azaphthalides, phenyl indolyl azaphthalide , Fluorans, stylinoquinolines, diazarhodamine lactones, etc., and these compounds are exemplified 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-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-diethylamino Fluorane, 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-d) pyrimidine-5,1' (3′H) isobenzofuran] -3′-one, 2- (di-n-butylamino) -8- (di-n-butylamino) -4-methyl-, spiro [5H- (1) benzopyrano ( 2,3-d) pyrimidine-5,1 '(3'H) isobenzofuran] -3'-one, 2- (di-n-butylamino) -8- (diethylamino) -4-methyl-, spiro [ 5H- (1) benzopyrano (2, 3-d) Pyrimidine-5,1 '(3'H) isobenzofuran] -3'-one, 2- (di-n-butylamino) -8- (N-ethyl-Ni-amylamino) -4 -Methyl-, spiro [5H- (1) benzopyrano (2,3-d) pyrimidine-5,1 '(3'H) isobenzofuran] -3'-one, 2- (di-n-butylamino)- 8- (Di-n-butylamino) -4-phenyl, 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-methylindole-3-yl) -4,5,6,7 can be given tetrachloro phthalide like.
Furthermore, there can be mentioned pyridine-based, quinazoline-based, bisquinazoline-based compounds and the like that are effective in developing fluorescent yellow to red color development.

As the electron-accepting compound of component (b), a group of compounds having active protons, a group of pseudo-acidic compounds (a group of compounds that are not acids but act as an acid in the composition and cause component (a) to develop color), electrons There is a group of compounds having pores.
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, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) ethylpropionate, 2,2-bis (4-hydroxyphenyl)- 4-methylpentane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 2,2-bis (4-hydroxyphenyl) n-heptane, 2,2-bis It is 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.

The component (c) of the reaction medium that causes the electron transfer reaction by the components (a) and (b) to occur reversibly in a specific temperature range will be described. Examples of the component (c) include alcohols, esters, ketones, ethers, and acid amides.
The component (c) is preferably a large hysteresis characteristic regarding the color density-temperature curve (a curve plotting a change in color density due to a temperature change changes the temperature from the low temperature side to the high temperature side and the high temperature side to the low temperature side). A carboxylic acid ester compound that exhibits a ΔT value (melting point-cloud point) of 5 ° C. or higher and lower than 50 ° C., which can form a reversible thermochromic composition that exhibits color memory, and changes color when changing to the side) For example, a carboxylic acid ester having a substituted aromatic ring in the molecule, an ester of a carboxylic acid having an unsubstituted aromatic ring and an aliphatic alcohol having 10 or more carbon atoms, a carboxylic acid ester having a cyclohexyl group in the molecule, 6 carbon atoms Fatty acid and unsubstituted aromatic alcohol or phenol ester, fatty acid having 8 or more carbon atoms and branched aliphatic alcohol or ester, dicarboxylic acid And esters of aromatic alcohols or branched aliphatic alcohols, dibenzyl cinnamate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, dicetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearin, Dimyristin, distearin and the like are used.

Also, fatty acid ester compounds obtained from an odd aliphatic monohydric alcohol having 9 or more carbon atoms and an aliphatic carboxylic acid having an even number of carbon atoms, n-pentyl alcohol or n-heptyl alcohol and an even fat having 10 to 16 carbon atoms. A fatty acid ester compound having a total carbon number of 17 to 23 obtained from a group carboxylic acid is also effective.
Specifically, n-pentadecyl acetate, n-tridecyl butyrate, n-pentadecyl butyrate, n-undecyl caproate, n-tridecyl caproate, n-pentadecyl caproate, n-nonyl caprylate, n-undecyl caprylate, N-tridecyl caprylate, n-pentadecyl caprylate, n-heptyl caprate, n-nonyl caprate, n-undecyl caprate, n-tridecyl caprate, n-pentadecyl caprate, n-pentyl laurate, lauric acid n-heptyl, n-nonyl laurate, n-undecyl laurate, n-tridecyl laurate, n-pentadecyl laurate, n-pentyl myristate, n-heptyl myristate, n-nonyl myristate, n-myristate Undecyl, n-tridecyl myristate, N-pentadecyl ristinate, n-pentyl palmitate, n-heptyl palmitate, n-nonyl palmitate, n-undecyl palmitate, n-tridecyl palmitate, n-pentadecyl palmitate, n-nonyl stearate, stearic acid n-undecyl, n-tridecyl stearate, n-pentadecyl stearate, n-nonyl eicosanoate, n-undecyl eicosanoate, n-tridecyl eicosanoate, n-pentadecyl eicosanoate, n-nonyl behenate, n-behenate Examples include undecyl, n-tridecyl behenate, and n-pentadecyl behenate.

As the ketones, aliphatic ketones having a total carbon number of 10 or more are effective, and 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, and 5-undecanone. 2-dodecanone, 3-dodecanone, 4-dodecanone, 5-dodecanone, 2-tridecanone, 3-tridecanone, 2-tetradecanone, 2-pentadecanone, 8-pentadecanone, 2-hexadecanone, 3-hexadecanone, 9-heptadecanone, 2 -Pentadecanone, 2-octadecanone, 2-nonadecanone, 10-nonadacanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, laurone, stearone and the like.
Further, arylalkyl ketones having 12 to 24 carbon atoms in total, such as n-octadecanophenone, n-heptadecanophenone, n-hexadecanophenone, n-pentadecanophenone, n-tetradecano Phenone, 4-n-dodecanacetophenone, 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-pentylacetophene Emissions, cyclohexyl phenyl ketone, benzyl -n- butyl ketone, 4-n-butyl acetophenone, n- hexanophenone, 4-isobutyl acetophenone, 1-acetonaphthone, 2-acetonaphthone, may be mentioned cyclopentyl phenyl ketone.

  As ethers, aliphatic ethers having a total carbon number of 10 or more are effective, and 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, undecane diol dimethyl ether, dodecane diol dimethyl ether, tridecane diol dimethyl ether, decane diol diethyl ether, undecane diol diethyl ether Etc.

〔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。〕

〔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。〕 Further, as the component (c), a compound represented by the following general formula (1) described in JP-A-2006-137886, or a general formula (described below) described in JP-A-2006-188660 ( The compound represented by 2) is preferably used.

Wherein, _{R 1} represents a hydrogen atom or a methyl group, m represents an integer of 0 to _2, one is for _{X 1, X 2 - (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. ]

[Wherein, 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 The alkoxy group of number 1-4, and a halogen are shown. ]

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.
In the formula (2), R represents an alkyl group or alkenyl group having 8 or more carbon atoms, preferably an alkyl group having 10 to 24 carbon atoms, more preferably an alkyl group having 12 to 22 carbon atoms.
Examples of the compound include octanoic acid-4-benzyloxyphenylethyl, nonanoic acid-4-benzyloxyphenylethyl, decanoic acid-4-benzyloxyphenylethyl, undecanoic acid-4-benzyloxyphenylethyl, dodecanoic acid-4- Benzyloxyphenylethyl, tridecanoic acid-4-benzyloxyphenylethyl, tetradecanoic acid-4-benzyloxyphenylethyl, pentadecanoic acid-4-benzyloxyphenylethyl, hexadecanoic acid-4-benzyloxyphenylethyl, heptadecanoic acid-4- Benzyloxyphenylethyl, octadecanoic acid-4-benzyloxyphenylethyl, 1,1-diphenylmethyl octanoate, 1,1-diphenylmethyl nonanoate, 1,1-diphenylmethyl decanoate, 1,1-didecanoic acid Phenylmethyl, 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 Examples include 1,1-diphenylmethyl and 1,1-diphenylmethyl octadecanoate.

  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 as follows. (B) Component 1, (b) Component 0.1-50, preferably 0.5-20, (C) Component 1-800, preferably 5-200 (all the above ratios) Part by mass).

  The microencapsulation of the reversible thermochromic composition includes interfacial polymerization method, interfacial polycondensation method, in situ polymerization method, submerged curing coating method, phase separation method from aqueous solution, phase separation method from organic solvent, melt dispersion There are a cooling method, an air suspension coating method, a spray drying method, and the like, which are appropriately selected according to the application. Further, a secondary resin film may be provided on the surface of the microcapsule according to the purpose to impart durability, or the surface characteristics may be modified for practical use.

The form of the microcapsule pigment does not refuse application of a circular cross-section, but a non-circular cross-section is effective.
The handwriting formed by writing, the microcapsule pigment is closely oriented and fixed in close contact with the writing surface on the long diameter side (maximum outer diameter side), and exhibits a high concentration of color development. The microcapsule pigment is slightly elastically deformed into a shape that relaxes the external force against the external force caused by friction caused by the frictional material, and the destruction of the microcapsule wall film is suppressed, and it is effectively expressed without impairing the thermal discoloration function. Can be made.
The above microcapsule pigments (including those having a circular cross-sectional shape) exhibit a decrease in ink outflow in systems where the average maximum outer diameter exceeds 5.0 μm, while the average maximum outer diameter is In a system of 0.5 μm or less, it is difficult to show high density color development. Preferably, the average value of the maximum outer diameter is in the range of 1 to 4 μm, the average particle diameter of the microcapsule [(maximum outer diameter + minimum at the center) The outer diameter) / 2] is preferably in the range of 1 to 3 μm.
Here, it is preferable that the reversible thermochromic composition: wall film = 7: 1 to 1: 1 (mass ratio), 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.

Examples of dyes that change or lose color with the reducing agent include methine dyes, trimethylmethane dyes, diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, cyanine dyes, azo dyes, anthraquinone dyes, and cyanine dyes. And dyes such as dyes,
Use alone or in combination.
It is preferable to use a basic dye as the dye, and in order to improve the color developability of the dye, it is preferable to adjust the pH of the ink to a range of 1 to 6, in particular, the stability of the ink, It is more preferable to adjust the pH of the ink to a range of 3 to 5 in order to easily obtain the effect of suppressing the discoloration of the handwriting due to the pH of the writing paper surface.
In order to adjust the pH of the ink to a range of 1 to 6, malic acid, oxalic acid, succinic acid, citric acid, tartaric acid, malonic acid, glycolic acid, gluconic acid and the like can be added.

  The ink composition containing the microcapsule pigment and a dye that changes color or loses color with a reducing agent includes a shear-thinning ink containing a shear-thinning agent and a water-soluble polymer flocculant to make the microcapsule pigment into a gradual aggregation state. Mention may be made of suspended cohesive inks. 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 derivatives thereof , Hydroxyethyl cellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000, mainly composed of alkyl esters of methacrylic acid, thickening agent having gelling ability extracted from seaweed such as glucomannan, agar and carrageenan Sugars, 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, polio Shi polyoxyethylene alkyl ether-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.

In the ink containing the polymer flocculant, the microcapsule pigment is liable to settle or float due to the specific gravity difference between the microcapsule pigment and the vehicle.
In order to eliminate this, microcapsule particles or resin particles having a specific gravity different from that of the reversible thermochromic microcapsule pigment can be added, and when the specific gravity of the reversible thermochromic microcapsule pigment is larger than the specific gravity of the vehicle, Microcapsule particles or resin particles having a specific gravity smaller than that of the vehicle are used. When the specific gravity of the reversible thermochromic microcapsule pigment is smaller than the specific gravity of the vehicle, microcapsule particles or resin particles having a specific gravity larger than that of the vehicle are used.
In other words, the specific gravity of the vehicle exists between the specific gravity of the reversible thermochromic microcapsule pigment during color development and the specific gravity of the microcapsule particles or resin particles.
By adding such microcapsule particles or resin particles, the mixed aggregate (reversible thermochromic microcapsule pigment and aggregate of microcapsule particles or resin particles) is adjusted in the vicinity of the specific gravity of the vehicle. The difference in specific gravity is reduced, and as a result, it becomes difficult to separate in ink, and it can be easily redispersed even if separated.
The microcapsule particles have the same capsule form as the reversible thermochromic microcapsule pigment, and the specific gravity can be changed depending on the type of inclusion.
The inclusions of the microcapsule particles include various liquids, gases, liquids and solids, liquids and solids, and reversible thermochromic microcapsule pigments. And (c) a reaction medium that determines the occurrence temperature of the color reaction of the both.
As the resin particles, polyolefin resin particles such as polyethylene, polystyrene, polypropylene, and ethylene vinyl acetate copolymer resin are preferably used.
The particle diameter of the resin particles is preferably 3 μm or less, more preferably 2 μm or less.
In addition to the powder particles, the resin particles may be resin emulsions or dispersion dispersions.
The microcapsule particles or resin particles may be blended in an amount of 2 to 20% by mass, preferably 5 to 20% by mass, and more preferably 5 to 15% by mass with respect to the total amount of the ink composition.
If it is less than 2% by mass, the effect of adjusting the specific gravity is insufficient, and if it exceeds 20% by mass, the balance of specific gravity may be impaired.
In the relationship among the specific gravity (X) at the time of color development of the reversible thermochromic microcapsule pigment, the specific gravity (Y) of the microcapsule particles or the resin particles, and the specific gravity (Z) of the vehicle, the formulas (1) and (2) By satisfying the relationship, or the relationship of the formulas (3) and (4), the reversible thermochromic microcapsule pigment is separated in the ink and the handwriting becomes thin, or the hard dispersibility is impaired due to the hard cake. It can be further prevented.
Formula (1) is Z + 0.02 <= X <= Z + 0.2, Preferably it is Z + 0.02 <= X <= Z + 0.15, More preferably, it is Z + 0.03 <= X <= Z + 0.1.
Formula (2) is Z-0.25 <= Y <= Z-0.03, Preferably it is Z-0.2 <= Y <= Z-0.03, More preferably, Z-0.15 <= Y <= Z--. 0.03.
On the other hand, Formula (3) is Z-0.25 <= X <= Z-0.03, Preferably it is Z-0.2 <= X <= Z-0.3, More preferably, Z-0.15 <= X <= 0.3. Z-0.03.
Formula (4) is Z + 0.02 <= Y <= Z + 0.2, Preferably it is Z + 0.02 <= Y <= Z + 015, More preferably, it is Z + 0.03 <= Y <= Z + 0.1.

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.

  Furthermore, the color tone of the colorant is mixed during writing by using a normal dye or pigment (non-color-changeable colorant) in combination with the microcapsule pigment and a dye that changes or loses color as a colorant. The handwriting can be visually recognized, and the color tone of the non-color-changing colorant can be visually recognized by applying heat or cold to the handwriting or attaching a color changing liquid.

The ink is used by filling a writing instrument such as a marking pen or a ballpoint pen with a marking pen tip or a ballpoint pen tip attached to the writing tip.
When filling the ball-point pen, the structure and shape of the ball-point pen itself are not particularly limited. For example, the ball-point pen has an ink containing tube filled with shear-thinning ink in the shaft cylinder, and the ink containing tube has a ball at the tip portion. An example is a ball-point pen that communicates with the tip mounted on the ink-jet head and has a liquid stopper for backflow prevention in close contact with the end face of the ink.
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 0.4 to 1.5 mm, more preferably 0.5 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 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.
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 in which a pen tip made of a processed body is mounted on a shaft cylinder directly or via a relay member, and the ink occlusion body of the marking pen in which the ink occlusion body and the pen tip are connected is impregnated with cohesive ink. An example is a marking pen in which a pen tip and an ink storage tube are arranged via a pen or a valve body that is opened when the pen tip is pressed, and ink is directly stored in the ink storage tube.
The nib is a porous member having continuous vents selected from the range of generally used porosity of 30 to 70%, 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 corresponding to 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 ballpoint pen and the marking pen is not limited to those described above, and a composite writing instrument (a double-headed type or a nib with a pen point with a different form or a pen point with which a different color tone is derived) is attached. It may be a pay-out type or the like.

A reducing agent is added to the color changing liquid used for changing or erasing the color changeable writing instrument ink.
Specific examples of the reducing agent include sodium sulfite, potassium sulfite, lithium sulfite, calcium sulfite, ammonium sulfite, zinc sulfite, sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, sodium hypochlorite, tin chloride, hydrosal A phyto etc. can be illustrated and sodium sulfite is used suitably from a viewpoint of discoloration or decoloring performance.
Moreover, an organic solvent and various additives can be mix | blended with the said discoloration liquid as needed, for example, erasability can be improved when alkanolamines, such as a triethanolamine, are added.

The discoloring applicator for storing the discoloring liquid has a simple structure applicator for directly attaching the stored discoloring liquid to the handwriting from the opening, and a cap provided with a liquid absorbing liquid such as a brush in the opening. An example of the applicator has a structure in which the liquid-absorbing liquid impregnates the color-changing liquid in the container in the fitted state, and the liquid-absorbing liquid is brought into contact with the handwriting and applied.
Also, it may be an applicator having the structure of a writing instrument, and an ink occlusion composed of a fiber bundle housed in a writing tip with a fiber tip, felt tip, plastic tip, brush tip, etc. attached to the applicator. A structure in which the body is impregnated with the color changing liquid and the color changing liquid is supplied to the writing tip part, the ink is directly stored in the shaft tube, and a liquid flow rate adjusting member composed of a comb groove-like liquid flow rate adjusting member or a fiber bundle is interposed. Marking pen, brush pen, shaft with a structure that supplies a predetermined amount of color-changing liquid to the writing tip, and a structure that supplies the color-changing liquid directly to the writing tip by a valve mechanism A structure that impregnates the color changing liquid into the occlusion body consisting of fiber bundles contained in the cylinder and supplies the color changing liquid to the writing tip with the ball-point pen tip. Liquid consisting of members and fiber bundles A structure for supplying a predetermined amount of the color changing liquid to the writing tip through the flow rate adjusting member, and a housing tube filled with the color changing liquid in the shaft cylinder, the housing pipe communicating with the ballpoint pen tip, and further the color changing A ballpoint pen having a structure in which a liquid stopper for preventing a backflow is disposed at the rear end of the liquid can be exemplified.

  The discoloring applicator (ball pen, marking pen, brush pen, etc.) is provided in a part of the writing instrument containing the ink for the discolorable writing instrument, specifically, the rear part (so-called double-headed writing instrument structure) and obtained by writing. The written handwriting can be made into a writing instrument excellent in portability that can be discolored or decolored by a single writing instrument.

Furthermore, the handwriting obtained by writing on the writing surface using the writing instrument can be discolored by heating or cooling.
When a microcapsule pigment containing a reversible thermochromic composition having color memory is used, the discolored state is maintained in a normal temperature range, so that the handwriting is heated or cooled to change the color again. There is a need.
Examples of the heating means include a method using a drier or rubbing with a finger, but it is preferable to erase the color by rubbing using a friction member or a friction body.
The friction member or the friction body is preferably an elastic body such as an elastomer or a plastic foam which is rich in elasticity and can generate frictional heat by generating appropriate friction during friction. Wood, metal, and fabric may be used.
Examples of the material of the friction member and the friction body include silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene block copolymer), and the like.
The friction member is excellent in portability by being fixed to a writing instrument.
Examples of the location where the friction member is fixed include a cap tip (top) or a shaft tube tip (portion where no writing tip is provided).

  In addition, a writing instrument set can be obtained by combining the writing instrument incorporating the ink for the color-changing writing instrument with the friction body and / or the color-changing applicator.

Examples are shown below, but the present invention is not limited to these examples.
In addition, the part in an Example is a mass part.
Example 1
Preparation of reversible thermochromic microcapsule pigment (a) 4,5,6,7-tetrachloro-3- [4- (diethylamino) -2-methylphenyl] -3- (1-ethyl-2-methyl) as component -1H-indol-3-yl) -1 (3H) -isobenzofuranone (3.0 parts), (b) component 4,4 '-(2-methylpropylidene) bisphenol (3.0 parts), 2,2- A reversible thermochromic composition consisting of 5.0 parts of bis (4′-hydroxyphenyl) -hexafluoropropane and 50.0 parts of 4-benzyloxyphenylethyl caprate as the component (c) is uniformly heated and dissolved. A solution prepared by mixing 25.0 parts of isocyanate and 50.0 parts of a co-solvent as a wall film material is emulsified and dispersed in a polyvinyl alcohol aqueous solution so as to form fine droplets. 2.5 parts of a functional aliphatic modified amine was added and stirring was continued to obtain a reversible thermochromic microcapsule pigment suspension.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle size of 2.5 μm, a complete color erasing temperature of 60 ° C., and a complete color development temperature of −20 ° C., which changes from blue to colorless according to temperature change.

Preparation of microcapsule particles 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 3.0 parts, 1,1-bis (4'-hydroxyphenyl) decane 3.0 parts, butyl palmitate 50.0 The composition consisting of parts is uniformly heated and dissolved, and a solution in which 25.0 parts of isocyanate and 50.0 parts of a co-solvent are mixed as a wall film material is emulsified and dispersed so as to form microdroplets in an aqueous polyvinyl alcohol solution. Stirring was continued while heating, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was further continued to obtain a microcapsule particle suspension.
The suspension was centrifuged to isolate microcapsule particles.
The average particle size of the microcapsule particles was 2.5 μm.

Preparation of an ink composition for a color-changing writing instrument 10.4 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to cause the microcapsule pigment to develop a blue color and left at room temperature), 5.6 parts of microcapsule particles, hydroxyethyl cellulose [manufactured by Union Carbide Japan Co., Ltd., trade name: cellosize WP-09L] 0.4 part, 17.0 parts of glycerin, reducing decoloring dye [Hodogaya Chemical Co., Ltd. Product name: SWT-Red-4] 0.3 parts, antifoaming agent 0.02 parts, preservative 1.0 part, water 65.18 parts, 10% diluted phosphoric acid solution 0.1 part was added. Then, stirring was performed uniformly, and the pH of the ink was adjusted to 3.6 to obtain an ink composition for a color-changing writing instrument.

Preparation of writing instrument The ink and the stirrer were built in the shaft cylinder, and a marking pen body (chisel type fiber pen body) was attached to the tip portion through a valve mechanism to obtain a writing instrument (marking pen).
The valve mechanism includes a valve seat, a valve body, and a spring that biases the valve body so as to press the valve seat against the valve seat, and has a structure in which the valve is opened by writing pressure applied to the pen body during writing.
The writing instrument is provided with a detachable cap, and the cap is provided with a SEBS resin as a friction member at the top.

A purple character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting has a purple color at room temperature (25 ° C.), and when the character is rubbed with a friction member attached to the cap, the character becomes pink. When the coating solution was applied from the pink handwriting, it became colorless.
This state was maintained at room temperature, and turned blue when cooled to −20 ° C. or lower.
Separately from this, when the coating liquid is applied to purple characters formed on the paper surface using the writing instrument, the color turns blue. When the blue handwriting is rubbed with a friction member, the character becomes colorless.
This state was maintained at room temperature, and turned blue when cooled to −20 ° C. or lower.

Example 2
Preparation of reversible thermochromic microcapsule pigment (a) 3.0 parts of 4- [2,6-bis (2-ethoxyphenyl) -4-pyridiel] -N, N-dimethylbenzenamine as component (b) component 4,4 '-(2-methylpropylidene) bisphenol 3.0 parts, 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 5.0 parts, (ha) component 4-benzyl caprate A reversible thermochromic composition composed of 50.0 parts of oxyphenylethyl was uniformly heated and dissolved, and a solution in which 25.0 parts of isocyanate and 50.0 parts of a co-solvent were mixed as a wall film material in an aqueous polyvinyl alcohol solution. After emulsifying and dispersing into fine droplets and stirring while warming, 2.5 parts of a water-soluble aliphatic modified amine is added, and stirring is continued to continue the reversible thermochromic microcapsule face. A suspension of the material was obtained.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle size of 2.5 μm, a complete color erasing temperature of 60 ° C., a complete color development temperature of −20 ° C., and changes color from yellow to colorless according to temperature change.

Preparation of microcapsule particles 1,1-bis (4′-hydroxyphenyl) decane 3.0 parts, 2,2-bis (4′-hydroxyphenyl) hexafluoropropane 3.0 parts, butyl palmitate 50.0 parts A composition comprising 25.0 parts of isocyanate and 50.0 parts of a co-solvent as a wall film material is uniformly heated and dissolved, and then emulsified and dispersed in a polyvinyl alcohol aqueous solution so as to form fine droplets. Stirring was continued while warming, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was further continued to obtain a microcapsule particle suspension.
The suspension was centrifuged to isolate microcapsule particles.
The average particle size of the microcapsule particles was 2.5 μm.

Preparation of ink composition for color-changing writing instrument 10.4 parts of the reversibly thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to cause the microcapsule pigment to develop a yellow color and left at room temperature), 5.6 parts of microcapsule particles, hydroxyethyl cellulose [manufactured by Union Carbide Japan Co., Ltd., trade name: cellosize WP-09L] 0.4 part, 17.0 parts of glycerin, reducing decoloring dye [Hodogaya Chemical Co., Ltd. Product name: SWT-Red-4] 0.3 parts, antifoaming agent 0.02 parts, preservative 1.0 part, water 65.18 parts, 10% diluted phosphoric acid solution 0.1 part was added. Then, stirring was performed uniformly, and the pH of the ink was adjusted to 3.6 to obtain an ink composition for a color-changing writing instrument.

Preparation of writing instrument The ink and the stirrer were built in the shaft cylinder, and a marking pen body (chisel type fiber pen body) was attached to the tip portion through a valve mechanism to obtain a writing instrument (marking pen).
The valve mechanism includes a valve seat, a valve body, and a spring that biases the valve body so as to press the valve seat against the valve seat, and has a structure in which the valve is opened by writing pressure applied to the pen body during writing.
The writing instrument is provided with a detachable cap, and the cap is provided with a SEBS resin as a friction member at the top.

An orange highlight (handwriting) was formed by writing on the characters printed on the paper using the writing instrument.
The handwriting is orange at room temperature (25 ° C.) and turns pink when rubbed with a friction member attached to the cap. When the coating solution was applied from the pink handwriting, it became colorless.
This state was maintained at room temperature, and turned yellow when cooled to -20 ° C or lower.
Separately from this, writing on the letters printed on the paper using the writing instrument to form an orange highlight (handwriting), it turns yellow when the coating solution is applied, and further colorless when rubbed with a friction member Become.
This state was maintained at room temperature, and turned yellow when cooled to -20 ° C or lower.

Example 3
Preparation of reversible thermochromic microcapsule pigment (I) 2- (Dibutylamino) -8- (Diventylamino) -4-methyl-spiro [5H- [1] benzopyrano [2,3-g] pyrimidine as component (a) 1.5 parts of -5,1 '(3H) -isobenzofuran] -3-one, 10.0 parts of 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane as component (b), ) A reversible thermochromic composition comprising 50.0 parts of 4-benzyloxyphenylethyl caprate as a component was uniformly heated and dissolved, and 25.0 parts of isocyanate and 50.0 parts of a co-solvent were mixed as a wall film material. The solution is emulsified and dispersed in polyvinyl alcohol aqueous solution so as to form fine droplets. After stirring while heating, 2.5 parts of a water-soluble aliphatic modified amine is added, and further stirring is continued to achieve reversible thermochromic properties. To obtain a microcapsule pigment suspension.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle diameter of 2.5 μm, a complete color erasing temperature of 60 ° C., and a complete color development temperature of −20 ° C., and changes from pink to colorless according to temperature change.

Preparation of microcapsule particles 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 3.0 parts, 1,1-bis (4'-hydroxyphenyl) decane 3.0 parts, cetyl caprate 50.0 The composition consisting of parts is uniformly heated and dissolved, and a solution in which 25.0 parts of isocyanate and 50.0 parts of a co-solvent are mixed as a wall film material is emulsified and dispersed so as to form microdroplets in an aqueous polyvinyl alcohol solution. Stirring was continued while heating, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was further continued to obtain a microcapsule particle suspension.
The suspension was centrifuged to isolate microcapsule particles.
The average particle size of the microcapsule particles was 2.5 μm.

Preparation of ink composition for color-changing writing instrument: 10.4 parts of the reversible thermochromic microcapsule pigment (cooled to -20 ° C. or lower in advance to develop the color of the microcapsule pigment in a pink color and left at room temperature) 5.6 parts of microcapsule particles, hydroxyethyl cellulose [manufactured by Union Carbide Japan Co., Ltd., trade name: Cellosize WP-09L] 0.4 part, 17.0 parts of glycerin, reducing decoloring dye [Hodogaya Chemical Industries ( Co., Ltd., trade name: SWT-Orange-1] 0.06 part, reducing decoloring dye [Hodogaya Chemical Co., Ltd., trade name: Diamond Green GH] 0.3 part, malic acid 0.6 Part, acid dye [Orient Kogyo Co., Ltd., trade name: Water Blue 106-L] 0.01 part, antifoaming agent 0.02 part, preservative 1.0 part, water 65.51 part, 10% dilution Phosphate solution 0.1 part was added, it stirred uniformly, the pH of the ink was adjusted to 3.4, and the ink composition for discolorable writing instruments was obtained.

Preparation of writing instrument The ink and the stirrer were built in the shaft cylinder, and a marking pen body (chisel type fiber pen body) was attached to the tip portion through a valve mechanism to obtain a writing instrument (marking pen).
The valve mechanism includes a valve seat, a valve body, and a spring that biases the valve body so as to press the valve seat against the valve seat, and has a structure in which the valve is opened by writing pressure applied to the pen body during writing.
The direct liquid writing instrument is provided with a detachable cap, and a SEBS resin is attached as a friction member to the rear end of the shaft tube.

A blue character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting has a blue color at room temperature (25 ° C.), and when the character is rubbed with a friction member attached to the cap, the character turns green. When the coating solution was applied from the green handwriting, it turned pale blue.
This state was maintained at room temperature, and turned blue-green upon cooling to −20 ° C. or lower.
Apart from this, when the coating liquid is applied to blue letters formed on the paper surface using the writing instrument, a blue-green color is obtained. When the blue-green handwriting is rubbed with a friction member, the character turns light blue.
This state was maintained at room temperature, and turned blue-green upon cooling to −20 ° C. or lower.

Example 4
Preparation of reversible thermochromic microcapsule pigment A (i) 4,5,6,7-tetrachloro-3- [4- (diethylamino) -2-methylphenyl] -3- (1-ethyl-2-) as component Methyl-1H-indol-3-yl) -1 (3H) -isobenzofuranone (3.0 parts), (ro) component 4,4 '-(2-methylpropylidene) bisphenol (3.0 parts), 2,2 -A reversible thermochromic composition comprising 5.0 parts of bis (4'-hydroxyphenyl) -hexafluoropropane and 50.0 parts of 4-benzyloxyphenylethyl caprate as the component (c) is uniformly heated and dissolved. Then, a solution prepared by mixing 25.0 parts of isocyanate and 50.0 parts of a co-solvent as a wall film material is emulsified and dispersed to form fine droplets in an aqueous polyvinyl alcohol solution. 2.5 parts of a soluble aliphatically modified amine was added and stirring was continued to obtain a reversible thermochromic microcapsule pigment suspension.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle size of 2.5 μm, a complete color erasing temperature of 60 ° C., and a complete color development temperature of −20 ° C., which changes from blue to colorless according to temperature change.

Preparation of reversible thermochromic microcapsule pigment B (a) 3.0 parts of 4- [2,6-bis (2-ethoxyphenyl) -4-pyridiel] -N, N-dimethylbenzenamine as component (b) As component, 3.0 parts of 4,4 '-(2-methylpropylidene) bisphenol, 5.0 part of 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane, (ha) capric acid 4- A reversible thermochromic composition composed of 50.0 parts of benzyloxyphenylethyl is uniformly heated and dissolved, and a solution in which 25.0 parts of isocyanate and 50.0 parts of a co-solvent are mixed as a wall film material in an aqueous polyvinyl alcohol solution. The mixture is emulsified and dispersed to form fine droplets, and stirring is continued while heating. Then, 2.5 parts of a water-soluble aliphatic modified amine is added, and stirring is further continued to form a reversible thermochromic microcapsule. A pigment suspension was obtained.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle size of 2.5 μm, a complete color erasing temperature of 60 ° C., a complete color development temperature of −20 ° C., and changes color from yellow to colorless according to temperature change.

Preparation of microcapsule particles 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 3.0 parts, 1,1-bis (4'-hydroxyphenyl) decane 3.0 parts, cetyl caprate 50.0 The composition consisting of parts is uniformly heated and dissolved, and a solution in which 25.0 parts of isocyanate and 50.0 parts of a co-solvent are mixed as a wall film material is emulsified and dispersed so as to form microdroplets in an aqueous polyvinyl alcohol solution. Stirring was continued while heating, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was further continued to obtain a microcapsule particle suspension.
The suspension was centrifuged to isolate microcapsule particles.
The average particle size of the microcapsule particles was 2.5 μm.

Preparation of ink composition for color-changing writing instrument: 3.1 parts of the reversible thermochromic microcapsule pigment A (previously cooled to −20 ° C. or less to cause the microcapsule pigment to develop a blue color and left at room temperature) 7.3 parts of the reversible thermochromic microcapsule pigment B (previously cooled to −20 ° C. or lower to cause the microcapsule pigment to develop a yellow color and left at room temperature), 5.6 parts of microcapsule particles , Hydroxyethylcellulose [Union Carbide Japan Co., Ltd., trade name: Cello size WP-09L] 0.4 part, glycerin 17.0 parts, reducing decoloring dye [Hodogaya Chemical Co., Ltd., trade name: SWT -Red-4] 0.3 part, acid dye [Orient Kogyo Co., Ltd., trade name: Water Blue 106-L] 0.01 part, antifoaming agent 0.02 part, preservative 1.0 part, water 65 .17 parts, 0.1 part of a 10% diluted phosphoric acid solution was added and stirred uniformly, and the pH of the ink was adjusted to 3.6 to obtain an ink composition for a color-changing writing instrument.

Preparation of writing instrument The ink and the stirrer were built in the shaft cylinder, and a marking pen body (chisel type fiber pen body) was attached to the tip portion through a valve mechanism to obtain a writing instrument (marking pen).
The valve mechanism includes a valve seat, a valve body, and a spring that biases the valve body so as to press the valve seat against the valve seat, and has a structure in which the valve is opened by writing pressure applied to the pen body during writing.
The writing instrument is provided with a detachable cap, and a SEBS resin is attached as a friction member to the rear end portion of the shaft cylinder.

A black highlight (handwriting) was formed by writing on the characters printed on the paper using the writing instrument.
The handwriting has a black color at room temperature (25 ° C.) and turns pale purple when rubbed with a friction member attached to the cap. When the coating solution was applied from the light purple handwriting, it turned pale blue.
This state was maintained at room temperature, and turned green when cooled to -20 ° C or lower.
Separately from this, writing on the letters printed on the paper using the writing instrument to form black highlights (handwriting), it turns green when the coating solution is applied, and light blue when rubbed with a friction member become.
This state was maintained at room temperature, and turned green when cooled to -20 ° C or lower.

Example 5
Preparation of reversible thermochromic microcapsule pigment (a) 4,5,6,7-tetrachloro-3- [4- (diethylamino) -2-methylphenyl] -3- (1-ethyl-2-methyl) as component -1H-indol-3-yl) -1 (3H) -isobenzofuranone (3.0 parts), (b) component 4,4 '-(2-methylpropylidene) bisphenol (3.0 parts), 2,2- A reversible thermochromic composition consisting of 5.0 parts of bis (4′-hydroxyphenyl) -hexafluoropropane and 50.0 parts of 4-benzyloxyphenylethyl caprate as the component (c) is uniformly heated and dissolved. A solution prepared by mixing 25.0 parts of isocyanate and 50.0 parts of a co-solvent as a wall film material is emulsified and dispersed in a polyvinyl alcohol aqueous solution so as to form fine droplets. 2.5 parts of a functional aliphatic modified amine was added and stirring was continued to obtain a reversible thermochromic microcapsule pigment suspension.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle size of 2.5 μm, a complete color erasing temperature of 60 ° C., and a complete color development temperature of −20 ° C., which changes from blue to colorless according to temperature change.

Preparation of microcapsule particles 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 3.0 parts, 1,1-bis (4'-hydroxyphenyl) decane 3.0 parts, butyl palmitate 50.0 The composition consisting of parts is uniformly heated and dissolved, and a solution in which 25.0 parts of isocyanate and 50.0 parts of a co-solvent are mixed as a wall film material is emulsified and dispersed so as to form microdroplets in an aqueous polyvinyl alcohol solution. Stirring was continued while heating, 2.5 parts of a water-soluble aliphatic modified amine was added, and stirring was further continued to obtain a microcapsule particle suspension.
The suspension was centrifuged to isolate microcapsule particles.
The average particle size of the microcapsule particles was 2.5 μm.

Preparation of an ink composition for a color-changing writing instrument 10.4 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to cause the microcapsule pigment to develop a blue color and left at room temperature), 5.6 parts of microcapsule particles, hydroxyethyl cellulose [manufactured by Union Carbide Japan Co., Ltd., trade name: cellosize WP-09L] 0.4 part, 17.0 parts of glycerin, reducing decoloring dye [Hodogaya Chemical Co., Ltd. Product name: SWT-Red-4] 0.3 parts, antifoaming agent 0.02 parts, preservative 1.0 part, water 65.18 parts, 10% diluted phosphoric acid solution 0.1 part was added. Then, stirring was performed uniformly, and the pH of the ink was adjusted to 3.6 to obtain an ink composition for a color-changing writing instrument.

Preparation of writing instrument The ink and the stirrer were built in the shaft cylinder, and a marking pen body (chisel type fiber pen body) was attached to the tip portion through a valve mechanism to obtain a writing instrument (marking pen).
The valve mechanism includes a valve seat, a valve body, and a spring that biases the valve body so as to press the valve seat against the valve seat, and has a structure in which the valve is opened by writing pressure applied to the pen body during writing.
The writing instrument is provided with a detachable cap.

Preparation of writing instrument set The writing instrument set was obtained by combining the writing instrument and a rectangular SEBS resin friction body.

A purple character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting has a purple color at room temperature (25 ° C.), and when characters are rubbed with a friction body, the characters turn pink. When the coating solution was applied from the pink handwriting, it became colorless.
This state was maintained at room temperature, and turned blue when cooled to −20 ° C. or lower.
Separately from this, when the coating liquid is applied to purple characters formed on the paper surface using the writing instrument, the color turns blue. When the blue handwriting is rubbed with a friction body, the character becomes colorless.
This state was maintained at room temperature, and turned blue when cooled to −20 ° C. or lower.

It is explanatory drawing which shows the discoloration behavior of a heat decoloring type reversible thermochromic microcapsule pigment. It is explanatory drawing which shows the discoloration behavior of the heat decoloring type reversible thermochromic microcapsule pigment having color memory.

Explanation of symbols

t ₁ Complete color development temperature of reversible thermochromic microcapsule pigment t ₂ Color development start temperature of reversible thermochromic microcapsule pigment t ₃ Decolorization start temperature of reversible thermochromic microcapsule pigment t ₄ Reversible thermochromic microcapsule pigment Full color erasing temperature

Claims (9)

  From water, (a) an electron-donating color-forming organic compound as a colorant, (b) an electron-accepting compound, and (c) a reaction medium that controls the color reaction of (a) and (b) above An ink composition for a color-changing writing instrument comprising a microcapsule pigment encapsulating the reversible thermochromic composition and a dye that changes color or loses color with a reducing agent. The microcapsule pigment, color density - exhibit photochromic colored state and the colorless state shows a large hysteresis characteristic with respect to temperature curve, the pigment is the process of temperature increase from the colored state, decoloring and reach a temperature t ₃ in is started, become completely colorless state at a temperature t ₄ above temperature range than the temperature t _3, the process of the temperature is lowered from colorless state, it begins to color to reach a temperature t ₂ less than the temperature t _3, the temperature t ₂ In the temperature range lower than the temperature t ₁ or less, the film is completely colored, and in the temperature range between the temperature t ₂ and the temperature t ₃ , it exhibits a hysteresis characteristic in which the colored state or the colorless state is selectively maintained, and the temperature t ₁ is in the range of -30 to 0 ° C., claim 1 discoloring ink composition for a writing instrument, wherein the temperature _{t 4} is in the range of 45 to 95 ° C..   The ink composition for a color-changing writing instrument according to claim 1 or 2, wherein the pH of the ink is in the range of 1 to 6.   The ink composition for a color-changing writing instrument according to any one of claims 1 to 3, comprising a non-color-changing colorant.   A writing instrument containing the ink composition for a color-changing writing instrument according to any one of claims 1 to 4.   6. The writing instrument according to claim 5, further comprising a color-changing applicator containing a color-changing liquid at a rear end portion of the writing instrument.   The writing instrument according to claim 5 or 6, comprising a friction member.   The writing instrument according to claim 7, comprising a cap, and a friction member provided on the cap.   A writing instrument set comprising the writing instrument according to claim 5 and a friction body.

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