JP6203550B2 - Reversible thermochromic water-based ink composition, writing instrument using the same, and writing instrument set - Google Patents

Description

  The present invention relates to a reversible thermochromic water-based ink composition, a writing instrument using the same, and a writing instrument set.

Conventionally, a reversible thermochromic aqueous ink composition that suppresses lightening and darkening of handwriting due to a difference in specific gravity between the reversible thermochromic microcapsule pigment and the vehicle in a water-based ink composition for writing instruments containing the reversible thermochromic microcapsule pigment. (For example, refer to Patent Documents 1 and 2).
The ink composition is capable of suppressing lightening and darkening of the handwriting. In particular, the handwriting lightens over time in an upright state (the writing tip is upward), or when transported in an upright state, This is a water-based ink composition for a writing instrument that has practicality without causing the handwriting to lighten by applying vibration during carrying.
Since the water-based ink composition for a writing instrument contains water as a solvent, it may affect the performance of the writing instrument, such as wrinkles generated over time, microorganisms growing, and writing defects and off-flavors.
Therefore, attempts have been made to add antifungal agents and preservatives to the water-based ink composition. However, since the water-based ink composition is added with polysaccharides and saccharides to improve the performance, soot and microorganisms are added. In many cases, the conditions are advantageous for breeding, and the effect may not be sufficiently exerted by adding a small amount of antifungal agents or preservatives.
Therefore, even if it is conceivable to add a preservative having a high antibacterial effect against sputum and microorganisms, those having a high antibacterial effect are often harmful to the human body. In addition, even when trying to apply food additives such as sodium dehydroacetate and potassium sorbate as highly safe preservatives, it is difficult to completely control and sterilize harmful bacteria because the preservatives have low water solubility. Met.

JP 2009-227954 A JP 2011-38048 A

  The present invention is intended to solve the above-described conventional problems, that is, it can sufficiently satisfy the writing performance for suppressing lightening and darkening of handwriting, and generation of wrinkles even after long-term storage. The present invention aims to provide a reversible thermochromic water-based ink composition excellent in antibacterial effect against harmful bacteria without causing spoilage due to the propagation of microorganisms and microorganisms, and a writing instrument and a writing instrument set using the same.

The present invention relates to a reversible thermochromic composition comprising water and (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. A reversible thermochromic microcapsule pigment encapsulating a product, a polymer flocculant selected from polyethylene oxide and water-soluble polysaccharide, and a plurality of carboxyls in the side chain as a comb-type polymer dispersant having a carboxyl group in the side chain Group-containing acrylic polymer, water-soluble resin selected from alkyd resin, styrene maleic acid copolymer, polyvinylpyrrolidone, polyvinyl alcohol , sugar alcohol having 3 carbon atoms , sugar alcohol having 4 or more carbon atoms, and cation And a reversible thermochromic water-based ink composition comprising a preservative having a property.
Further, the mass ratio of the comb polymer dispersant to the cationic preservative is 1: 1 to 1:10, and the cationic preservative is a pyridinium compound, a biguanide compound, or a chlorine compound. It is required to be selected from quaternary ammonium salt compounds, non-chlorine quaternary ammonium salt compounds, nonionic tertiary ammonium salt compounds, and to contain a non-discoloring colorant.
Furthermore, the writing instrument provided with the pen body which accommodates the said reversible thermochromic water-based ink composition in a shaft cylinder, and guide | leads out the ink composition in the said shaft cylinder is made into requirements.
Furthermore, the rear end of the pen body is in contact with an ink occlusion body composed of a fiber bundling body housed in a shaft cylinder, the ink occlusion body is impregnated with an ink composition, and the pen body is It is a requirement that it is a marking pen body and that it is provided with a friction member.
Furthermore, a writing instrument set including the writing instrument and a friction body is a requirement.

  The present invention can suppress the lightening and darkening of the handwriting, and in particular, the handwriting does not lighten over time in an upright state or the handwriting does not lighten by applying vibration during transportation or carrying. A reversible thermochromic water-based ink composition that exhibits writing performance, has excellent antibacterial effects against harmful bacteria, and does not cause spoilage or spoilage due to the growth of microorganisms even after long-term storage, and a writing instrument and writing instrument set using the same Can provide.

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. It is explanatory drawing which shows the discoloration behavior of a heat coloring type reversible thermochromic microcapsule pigment. It is explanatory drawing which shows one Example of the writing instrument of this invention. It is explanatory drawing which shows the other Example of the writing instrument of this invention.

The colorant contained in the ink composition includes (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 of the both occurs. A reversible thermochromic microcapsule pigment comprising microcapsules encapsulating a reversible thermochromic composition that is decolored by heating containing at least the essential three components.
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. Applying a reversible thermochromic microcapsule pigment containing a reversible thermochromic composition that has a relatively small characteristic (ΔH = 1 to 7 ° C.) (decolored by heating and develops color by cooling) (Fig. 1 Irradiation).

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 reversible thermochromic composition having a color memory property in a temperature range between t _{2 and} t ₃ (substantially two-phase holding temperature range) (decolored by heating and developed by cooling). Reversible thermochromic micro Capsule pigments 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, it is possible to exhibit any of the states of the colored state and the decolored state, between t ₂ and t ₃ is a region having a large difference in color density The temperature range is substantially the two-phase holding 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 can be obtained only in a freezing room, a cold district, etc., that is, −50 to 0 ° C., preferably −40 to − 5 ° C., more 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, ie 45 to 95 ° C., preferably 50 to 90
By specifying the temperature in the range of 60 ° C., more preferably in the range of 60 to 80 ° C., and specifying the ΔH value in the range of 40 to 100 ° 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 Fluoranes, styrinoquinolines, diazarhodamine lactones, pyridines, quinazolines, bisquinazolines and the like.
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, And a compound having an alkyl group such as a methyl group or a halogen atom such as a chloro group.

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, 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.

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 esters, ketones, ethers, alcohols, and acid amides.
As the component (c), the color density-temperature curve has a large hysteresis characteristic (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 exhibiting a ΔT value (melting point-cloud point) of 5 ° C. or more and less than 50 ° C., which can form a reversible thermochromic composition exhibiting color memory, which changes color when changing to Carboxylic acid ester having a substituted aromatic ring in the molecule, carboxylic acid ester having an unsubstituted aromatic ring and an aliphatic alcohol ester having 10 or more carbon atoms, carboxylic acid ester having a cyclohexyl group in the molecule, 6 or more 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 aroma Ester of alcohol or branched aliphatic alcohol, dibenzyl cinnamate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, dicetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearin, dimyristin, Distearin or the like is 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, 5-undecanone, 2 -Dodecanone, 3-dodecanone, 4-dodecanone, 5-dodecanone, 2-tridecanone, 3-tridecanone, 2-tetradecanone, 2-pentadecanone, 8-pentadecanone, 2-hexadecanone, 3-hexadecanone, 9-heptadecanone, 2-pentadecanone 2-octadecanone, 2-nonadecanone, 10-nonadecanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, laurone, stearone and the like.
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 include dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, didodecyl ether, ditrityl ether. Decyl ether, ditetradecyl ether, dipentadecyl ether, dihexadecyl ether, dioctadecyl ether, decane diol dimethyl ether, undecane diol dimethyl ether, dodecane diol dimethyl ether, tridecane diol dimethyl ether, decane diol diethyl ether, undecane diol diethyl ether, etc. Can be mentioned.

  As the alcohols, aliphatic monovalent saturated alcohols having 10 or more carbon atoms are effective. Decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl Alcohol, octadecyl alcohol, eicosyl alcohol, docosyl alcohol, etc. can be mentioned.

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

〔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。 Moreover, the compound shown by following General formula (1) can also be used as said (c) component.

[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.

  Further, as the electron-accepting compound, a specific alkoxyphenol compound having a linear or side chain alkyl group having 3 to 18 carbon atoms may be used (Japanese Patent Laid-Open Nos. 11-129623 and 11-5973), Hydroxybenzoic acid esters (Japanese Patent Laid-Open No. 2001-105732), gallic acid esters and the like (Japanese Patent Publication No. 51-44706, Japanese Patent Laid-Open No. 2003-253149) are used. A microcapsule pigment containing a reversible thermochromic composition that is decolored by cooling) can also be applied (see FIG. 3).

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 (B) Component 1 is in the range of (b) Component 0.1-50, preferably 0.5-20, (c) Component 1-800, preferably 5-200. Part by mass).
Here, in the reversible thermochromic microcapsule pigment or the ink, a colorant such as a non-thermochromic dye or pigment is blended to change the color from color (1) to color (2). Changes can also be exhibited.

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.
Examples of the material of the capsule include epoxy resin, urea resin, urethane resin, and isocyanate resin.
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.

As the microcapsule pigment, those having an average particle diameter of 0.1 to 5.0 μm, preferably 0.1 to 4.0 μm, more preferably 0.5 to 3.0 μm are used.
Further, the mass ratio of the reversible thermochromic composition to the microcapsule wall film is a reversible thermochromic composition: wall film = 7: 1 to 1: 1 (mass ratio), preferably 6: 1 to 1: 1. It is preferable to satisfy the range.
When the average particle diameter of the microcapsule pigment exceeds 5.0 μm, it is difficult to obtain a smooth writing feeling, and when the average value of the maximum outer diameter is less than 0.1 μm, it is difficult to exhibit high color density.
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 particle size and particle size distribution were measured using a laser diffraction / scattering particle size distribution measuring apparatus (manufactured by Horiba, Ltd .; LA-300), and the average particle size (median diameter) based on the numerical values. Is calculated on a volume basis.

The reversible thermochromic microcapsule pigment can be blended in an amount of 5 to 40% by mass, preferably 10 to 40% by mass, and more preferably 15 to 35% by mass with respect to the total amount of the ink composition.
If it is less than 5% by mass, the color density is insufficient, and if it exceeds 40% by mass, the ink outflow tends to be reduced and the writing performance tends to be impaired.

As a medium used for the ink, water and, if necessary, a water-soluble organic solvent are used.
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, and 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- Pyrrolidone, or the like is used.
Note that the microcapsule pigment encapsulating the reversible thermochromic composition having a large hysteresis width has a specific gravity of more than 1, so that the water-soluble organic solvent to be applied is preferably more than 1.1.
Glycerin is preferably used as the water-soluble organic solvent, and can be blended in an amount of 5 to 40% by mass, preferably 25 to 40% by mass, and more preferably 30 to 35% by mass with respect to the total amount of the ink composition.

By adding a water-soluble polymer flocculant into the ink, the flocculant causes a loose bridging action between the microcapsule pigments and exhibits a loose flocculent state. Such an ink exhibiting a loose aggregation state can suppress the separation of the microcapsule pigment.
A water-soluble polymer is used as the polymer flocculant, and examples thereof include polyvinyl pyrrolidone, polyethylene oxide, and water-soluble polysaccharides.
Examples of the water-soluble polysaccharides include tragacanth gum, guar gum, pullulan, cyclodextrin, water-soluble cellulose derivatives and the like. Specific examples of water-soluble cellulose derivatives include methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose. Etc.
In the ink composition of the present invention, any water-soluble polymer showing a loose bridging action between microcapsule pigment particles can be applied, and among these, a water-soluble cellulose derivative functions effectively.
Two or more kinds of the polymer flocculants can be used in combination.

Along with the polymer flocculant, a comb-type polymer dispersant having a carboxyl group in the side chain and a cationic preservative are used in combination, so that the dispersibility of loose aggregates of microcapsule pigments by the polymer flocculant is reduced. Further improve.
The comb polymer dispersant having a carboxyl group in the side chain is not particularly limited as long as it is a comb polymer compound having a plurality of carboxyl groups in the side chain, but a plurality of carboxyl groups in the side chain. An acrylic polymer compound having the following formula is suitable. Examples of the compound include trade name: Solsperse 43000 manufactured by Nippon Lubrizol Corporation.

The cationic preservative suppresses settling of the microcapsule pigment due to vibration when the ink composition is filled into a writing instrument as described above and put to practical use.
This is due to the ionic synthesis of the microcapsule pigment loose agglomerates by the comb-type polymer dispersant having a carboxyl group in the side chain and the cationic preservative, thereby reducing the cohesive strength of the microcapsule pigment loose agglomerates. It is because the dispersibility of the microcapsule pigment in the ink composition can be improved by further strengthening.
The mass ratio of the comb-type polymer dispersant having a carboxyl group in the side chain and the preservative having a cationic property is 1: 1 to 1:10, preferably 1: 1 to 1: 5. By satisfying the above, it is possible to improve the cohesive force of the loose aggregate of the microcapsule pigment, and to sufficiently exhibit the dispersibility of the aggregate of the microcapsule pigment and the suppression of sedimentation of the microcapsule pigment due to vibration.

Examples of the cationic preservative include pyridinium compounds, biguanide compounds, chlorine quaternary ammonium salt compounds, non-chlorine quaternary ammonium salt compounds, nonionic tertiary ammonium salt compounds, nitrogen sulfur compounds, and the like. It is done.
An example of the pyridinium compound is cetylpyridinium chloride.
Examples of the biguanide compounds include polyhexamethylene biguanide, polyhexamethylene biguanide hydrochloride, and polyaminopropyl biguanide.
Examples of the chlorinated quaternary ammonium salt compound include benzalkonium chloride, benzethonium chloride and decalinium chloride.
Examples of the non-chlorine quaternary ammonium salt compounds include alkyldimethylbenzylammonium chloride, didecyldimethylammonium chloride, didecyldimethylammonium adipate, didecyldimethylammonium gluconate, didecylmonomethylhydroxyethylammonium chloride, didecylmonomethylhydroxyethyl. Examples include ammonium adipate, didecyl monomethylhydroxyethylammonium gluconate, didecylmonomethylhydroxyethylammonium sulfonate, and didecyldimethylammonium propionate.
Examples of the nonionic tertiary ammonium salt compound include trialkylamine.
As other preservatives, 2-bromo-2-nitropropane-1,3-diol (bronopol) 1,4bis (3,3 ′-(1-decylpyridinium) methyloxy) butanedibromide, 3-iodo- 2-proponyl butyl carbamate, sodium-pyridine thiol-1-oxy and the like.

The water-soluble resin can impart adhesion and viscosity to the paper surface, and the above-described comb-type polymer dispersant having a carboxyl group in the side chain and a cationic preservative in ink. Has a function to enhance the sex.
Examples of the water-soluble resin include alkyd resins, acrylic resins, styrene maleic acid copolymers, cellulose derivatives, polyvinyl pyrrolidone, polyvinyl alcohol, dextrin, and preferably polyvinyl alcohol is used.
Furthermore, the polyvinyl alcohol is more preferably used because partially saponification type polyvinyl alcohol having a saponification degree of 70 to 89 mol% is rich in solubility even in an acidic region.
The addition amount of the water-soluble resin is 0.3 to 3.0% by mass, preferably 0.5 to 1.5% by mass in the ink.

Examples of the sugar alcohol having 3 or more carbon atoms include glycerin, erythritol, threitol, ribitol, xylitol, arabinitol, sorbitol, iditol, mannitol, poremitol, perseitol, octitol, other linear oligosaccharide alcohols, branched oligosaccharide alcohols, reduction Starch decomposition products (reduced starch saccharification product) etc. are mentioned.
In addition, among the sugar alcohols, by using a sugar alcohol having 3 carbon atoms and a sugar alcohol having 4 or more carbon atoms in combination, a moisturizing effect is imparted to function as a cap-off property imparting agent or a specific gravity adjusting agent for the ink composition. In addition, it is possible to provide a function of improving the outflow property of the ink (ejection property from the pen body).

  In addition, benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, saponin and other anticorrosive agents, urea, nonionic surfactants, reduced or non-reduced starch hydrolysates, trehalose, etc. Wetting agents such as saccharides, oligosaccharides, sucrose, cyclodextrin, glucose, dextrin, sorbit, mannitol, sodium pyrophosphate, antifoaming agents, fluorine surfactants and nonionic surfactants that improve ink permeability May be used.

The ink composition suppresses aggregation and sedimentation in a low temperature range of the reversibly thermochromic microcapsule pigment contained by adjusting the pH to 3 to 8, preferably 4 to 7, more preferably 5 to 6. be able to.
When the pH exceeds 8, it tends to impair ink outflow properties when left in a low temperature range, that is, a temperature range where the ink freezes, and when the pH is less than 3, the reversible thermochromic composition encapsulated in the capsule. The color developability becomes strong, and there may be a problem that a color residue is generated at the time of decoloring.
The water-soluble resin is preferably a water-soluble resin that is soluble in the ink composition when the pH of the ink composition is in the range of 3 to 8.

The ink composition has a surface tension adjusted to 25 to 45 mN / m, preferably 30 to 45 mN / m, more preferably 30 to 40 mN / m.
By adjusting the surface tension within the above range, it is difficult to cause blurring when written, and the ink can be left in a temperature range below 0 ° C. where the ink freezes or even in a high temperature range, for example, 50 ° C. It is difficult to cause variations in handwriting density and writing width depending on the storage environment and use environment without impairing the flowability.
When the surface tension is less than 25 mN / m, the outflow property of the ink tends to be unstable, and the handwriting density becomes non-uniform. Further, when the surface tension exceeds 45 mN / m, line breakage is likely to occur, and the ink outflow amount decreases due to the storage environment and use environment described above, and the handwriting density decreases, and the writing width tends to vary. .

The pen body is preferably a marking pen body, and examples thereof include a pen body made of fiber, felt, plastic, or the like.
The tip shape of the marking pen body may be either a bullet type or a chisel type.
In addition, a brush pen body and a ballpoint pen body can be used. As the brush pen body, a fiber bundling body in which fibers are closely bundled in the longitudinal direction, a plastic porous body having continuous pores, and a heat-sealing of synthetic resin fibers. Examples thereof include a resin processed body, and a soft resin or elastomer extrusion processed body.
As the ballpoint pen body, metal is cut to form a ball receiving seat and an ink lead-out portion inside, a plurality of inward protruding portions are provided on the inner surface near the tip of the metal pipe by pressing deformation from the outer surface, An ink outflow gap extending radially outward from the central portion between the inward protruding portions is exemplified.
The ball held by the ballpoint pen body has an outer diameter of 0.3 to 2.0 mm, preferably 0.4 to 1.5 mm, more preferably 0.5 to 0.5 mm, such as cemented carbide, stainless steel, ruby and ceramic. A 1.0 mm ball is effective.
The ballpoint pen body is provided with a resilient member that bounces the rear end of the ball forward so that the ball is pressed against the inner edge of the tip of the pen body when not writing, and the ball is pressed by writing pressure when writing. The ink can be made to flow backward by allowing it to retreat.
As the shaft cylinder, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, or nylon is preferably used.
In addition, as a structure of the writing instrument for containing the ink composition, a direct liquid writing instrument having a structure in which a valve mechanism is arranged in the shaft cylinder and the ink in the shaft cylinder is led to the pen body by opening the valve, Direct ink writing instruments with a structure in which ink is directly stored in the ink flow adjusting member composed of a comb groove-like ink flow adjusting member and a fiber bundle are included. A solid writing instrument having a structure in which the body is impregnated, the pen body is attached to the writing tip, and the rear end of the pen body is in contact with the ink occlusion body directly or via a connecting member is preferable.
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 fiber bundle may be one that has been processed by resin processing, heat sealing, or plasticizer.

The handwriting formed from the writing instrument containing the ink composition can be discolored by friction with a finger or application of a heating tool or a cooling tool.
Examples of the heating tool include an energization heating color changing tool equipped with a resistance heating element, a heating color changing tool filled with hot water, and a hair dryer. Preferably, a friction member or a friction body that can change color by a simple method is used. Is used.
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.
Although it is possible to rub the handwriting by using an eraser, it is preferable to use a friction member or a friction body as described above because erase scraps are generated at the time of friction.
As the material of the friction member and the friction body, silicone resin, SEBS resin (styrene ethylene butadiene styrene block copolymer), and polyester resin are preferably used, but the silicone resin adheres to the portion erased by friction. Since the handwriting tends to be repelled when writing repeatedly, SEBS resin and polyester resin are more preferably used.
The friction member may be an arbitrary-shaped member (friction body) that is separate from the writing instrument, but is excellent in portability by being fixed to the writing instrument.
In the case of a writing instrument having a cap, the location where the friction member is provided is not particularly limited. For example, when the cap itself is formed of a friction member, the shaft tube itself is formed of a friction member, or a clip is provided. The clip itself can be formed of a friction member, or the friction member can be provided at the tip end (top) of the cap or the rear end of the shaft cylinder (the portion where the writing tip is not provided).
In the case of a retractable writing instrument, the location where the friction member is provided is not particularly limited, but for example, the shaft cylinder itself is formed with a friction member, or when the clip is provided, the clip itself is formed with a friction member, A friction member can be provided in the vicinity of the shaft tube opening, the rear end portion of the shaft tube (the portion where the writing tip portion is not provided) or the knock portion.
Examples of the cooling / heating tool include a cooling / heating discoloration tool using a Peltier element, a cooling / heating discoloration tool filled with a coolant such as cold water and ice pieces, a refrigerator and a freezer.
Moreover, a writing instrument set can be obtained by combining the writing instrument and a friction body.

Examples of the reversible thermochromic water-based ink composition of the present invention, a writing instrument using the same, and a writing instrument set are shown below, but the present invention is not limited thereto.
In addition, the part in an Example shows a mass part.
The surface tension of the ink was measured with an automatic surface tension meter (CBVP-A3) manufactured by Kyowa Interface Science Co., Ltd. at a temperature of 20 ° C.

Example 1
Preparation of reversible thermochromic microcapsule pigment (I) 2- (dibutylamino) -8- (dipentylamino) -4-methyl-spiro [5H- [1] benzopyrano [2,3-g] pyrimidine-5 as component (a) , 1 ′ (3′H) -isobenzofuran] -3-one 1.0 part, (b) component 4,4 ′-(2-ethylhexane-1,1-diyl) diphenol 3.0 part, A reversible thermochromic composition having color memory consisting of 5.0 parts of 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane and 50.0 parts of 4-benzyloxyphenylethyl caprate as component (c) A microcapsule pigment suspension containing the product 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, a complete color erasing temperature of 58 ° C., a complete color development temperature of −20 ° C., and changes from pink to colorless according to temperature change.

Preparation of reversible thermochromic aqueous ink composition 20.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop a pink color), 0.5 parts of hydroxyethyl cellulose, comb-shaped Polymer dispersant [manufactured by Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000] 0.4 part, 1,4 bis (3,3 ′-(1-decylpyridinium) methyloxy) butanedibromide [Taisho Technos ( Co., Ltd., trade name: Bioside NEO] 0.5 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, sorbitol 15.0 parts, antifoaming agent 0.2 parts, water 47.9 parts. Thus, a reversible thermochromic water-based ink composition was obtained.
The ink composition had a pH of 7.00 and a surface tension of 41.5 mN / m.

Production of filling-type writing instrument (see Fig. 4)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. The pen body 3 (chisel type) was assembled in a connected state, and the cap 6 was attached to obtain a filling type writing instrument 1 (marking pen).
A SEBS resin is attached as a friction member 7 to the rear end portion of the shaft cylinder.

Using the writing instrument, writing was performed on characters printed on the paper surface to form pink highlights (handwriting).
The handwriting has a pink color at room temperature (25 ° C.). When the handwriting is rubbed with a friction body attached to the shaft tube, the handwriting is discolored and becomes colorless, and this state is maintained at room temperature. Then, by cooling to −20 ° C. or lower, the original pink color was restored, and the discoloration behavior was reproduced repeatedly.

Example 2
Preparation of reversible thermochromic microcapsule pigment (a) 3.0 parts of 4- [2,6-bis (2-ethoxyphenyl) -4-pyridinyl] -N, N-dimethylbenzenamine as component (b) Reversible thermal discoloration having color memory consisting of 10.0 parts of 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane and 50.0 parts of 4-benzyloxyphenylethyl caprate as component (c) A microcapsule pigment suspension encapsulating the composition 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 59 ° C., and a complete color development temperature of −20 ° C., and changes from yellow to colorless according to temperature change.

Preparation of reversible thermochromic aqueous ink composition 20.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop yellow color), 0.5 parts of hydroxyethyl cellulose, comb-shaped high 0.4 parts of a molecular dispersant [Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000], 0.5 parts of polyhexamethylene biguanide [Lonza Japan Co., Ltd., trade name: Proxel IB], polyvinyl alcohol 0. 5 parts, 15.0 parts of glycerin, 15.0 parts of xylitol, 0.2 part of antifoaming agent and 47.9 parts of water were mixed to obtain a reversible thermochromic aqueous ink composition.
The ink composition had a pH of 7.80 and a surface tension of 40.5 mN / m.

Production of filling-type writing instrument (see Fig. 4)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. The pen body 3 (chisel type) was assembled in a connected state, and the cap 6 was attached to obtain a filling type writing instrument 1 (marking pen).
A SEBS resin is attached as a friction member 7 to the rear end portion of the shaft cylinder.

A yellow highlight (handwriting) was formed by writing on the characters printed on the paper using the writing instrument.
The handwriting has a yellow color at room temperature (25 ° C.). When the handwriting is rubbed with a friction body attached to the shaft tube, the handwriting is decolored and becomes colorless, and this state is maintained at room temperature. By cooling to −20 ° C. or lower, the original yellow color was restored, and the discoloration behavior was reproduced repeatedly.

Example 3
Preparation of reversible thermochromic microcapsule pigment (a) 3.0 parts of 1,3-dimethyl-6-diethylaminofluorane as component (4) 4,4 '-(2-ethylhexane-1, 1- Diyl) Color comprising 3.0 parts of diphenol, 5.0 parts of 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane, and 50.0 parts of 4-benzyloxyphenylethyl caprate as component (c) A microcapsule pigment suspension containing a reversible thermochromic composition having a memory property 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., and a complete color development temperature of −20 ° C., which changes from orange to colorless according to temperature change.

Preparation of reversible thermochromic water-based ink composition 25.0 parts of the microcapsule pigment (previously cooled to -20 ° C. or less to develop an orange color), 0.5 part of hydroxyethyl cellulose, a comb polymer dispersant [ Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000] 0.4 part, polyhexamethylene biguanide [Lonza Japan Co., Ltd. trade name: Proxel IB] 0.5 part, polyvinyl alcohol 0.5 part, glycerin 15.0 parts, 15.0 parts of sorbitol, 0.2 part of an antifoaming agent and 42.9 parts of water were mixed to obtain a reversible thermochromic aqueous ink composition.
The ink composition had a pH of 7.75 and a surface tension of 41.4 mN / m.

Production of filling-type writing instrument (see Fig. 5)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. The pen body 3 (cannonball type) was assembled in a connected state, and a cap 6 was attached to obtain a filling pen 1 (marking pen).
The cap is formed by attaching SEBS resin as a friction member 7 on the top.

An orange character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting has an orange color at room temperature (25 ° C.). When the character is rubbed with a friction member attached to the cap, the character is discolored and becomes colorless, and this state is maintained at room temperature. Then, by cooling to −20 ° C. or lower, the original orange color was restored, and the discoloration behavior was repeatedly reproduced.

Example 4
Preparation of reversible thermochromic microcapsule pigment (a) 4.5 parts of 2- (2-chloroamino) -6-dibutylaminofluorane as component (4), 4,4 '-(2-ethylhexane- 1,1-diyl) diphenol 3.0 parts, 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 5.0 parts, (ha) 4-benzyloxyphenylethyl caprate as component 50.0 A microcapsule pigment suspension containing a reversible thermochromic composition having color memory properties consisting of parts was obtained.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle diameter of 2.4 μm, a complete color erasing temperature of 56 ° C., a complete color development temperature of −20 ° C., and changes color from black to colorless according to temperature change.

Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop black color), 0.5 part of hydroxyethyl cellulose, comb-shaped high 0.4 parts of molecular dispersant [manufactured by Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000], 3-iodo-2-proponylbutylcarbamate [trade name: Glycasil 2000] produced by Lonza Japan Co., Ltd. 5 parts, 0.5 parts of polyvinyl alcohol, 15.0 parts of glycerin, 15.0 parts of sorbitol, 0.2 part of antifoaming agent and 42.9 parts of water were mixed to obtain a reversible thermochromic aqueous ink composition. .
The ink composition had a pH of 6.90 and a surface tension of 39.8 mN / m.

Production of filling-type writing instrument (see Fig. 5)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. The pen body 3 (cannonball type) was assembled in a connected state, and a cap 6 was attached to obtain a filling pen 1 (marking pen).
The cap is formed by attaching SEBS resin as a friction member 7 on the top.

A black character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting is black at room temperature (25 ° C.), and when rubbed with a friction body attached to the cap, the handwriting is decolored and colorless, and this state is maintained at room temperature, By cooling to −20 ° C. or lower, the original black color was restored, and the discoloration behavior was reproduced repeatedly.

Example 5
Preparation of reversible thermochromic microcapsule pigment (a) 4,5,6,7-tetrachloro-3- [4- (dimethylamino) -2-methylphenyl] -3- (1-ethyl-2-) as component 2. 2.0 parts of methyl-1H-indol-3-yl) -1 (3H) -isobenzofuranone, 4,4 ′-(2-ethylhexane-1,1-diyl) diphenol as component (b) 0 parts, 5.0 parts of 2,2-bis (4′-hydroxyphenyl) -hexafluoropropane, and 50.0 parts of 4-benzyloxyphenylethyl caprate as component (c), reversible heat having color memory A microcapsule pigment suspension containing the color-changing composition 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 55 ° C., a complete color development temperature of −20 ° C., and changes from blue to colorless according to temperature change.

Preparation of reversible thermochromic aqueous ink composition 25.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop blue color), 0.5 part of hydroxyethyl cellulose, comb-shaped high 0.4 part of a molecular dispersant [manufactured by Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000], 1.0 part of didecyldimethylammonium propionate carbonate [manufactured by Lonza Japan Co., Ltd., trade name: CARBOQUAT], A reversible thermochromic aqueous ink composition was obtained by mixing 0.5 parts of polyvinyl alcohol, 15.0 parts of glycerin, 15.0 parts of sorbitol, 0.2 part of antifoaming agent and 42.4 parts of water.
The ink composition had a pH of 8.00 and a surface tension of 41.0 mN / m.

Production of filling-type writing instrument (see Fig. 5)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. It assembled in the connection state with the pen body 3 (bullet type), the cap 6 was mounted | worn, and the filling type writing instrument 1 (marking pen) was obtained.
The cap is formed by attaching SEBS resin as a friction member 7 on the top.

Blue letters (handwriting) were formed on the paper surface using the writing instrument.
The handwriting has a blue color at room temperature (25 ° C.), and when rubbed with a friction body attached to the cap, the handwriting is decolored and colorless, and this state is maintained at room temperature, By cooling to −20 ° C. or lower, the original blue color was restored, and the discoloration behavior was reproduced repeatedly.

Example 6
Preparation of reversible thermochromic microcapsule pigment (a) 4,5,6,7-tetrachloro-3- [4- (dimethylamino) -2-methylphenyl] -3- (1-ethyl-2-) as component 2. 2.0 parts of methyl-1H-indol-3-yl) -1 (3H) -isobenzofuranone, 4,4 ′-(2-ethylhexane-1,1-diyl) diphenol as component (b) 0 parts, 5.0 parts of 2,2-bis (4′-hydroxyphenyl) -hexafluoropropane, and 50.0 parts of 4-benzyloxyphenylethyl caprate as component (c), reversible heat having color memory A microcapsule pigment suspension containing the color-changing composition 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 55 ° C., a complete color development temperature of −20 ° C., and changes from blue to colorless according to temperature change.

Preparation of reversible thermochromic aqueous ink composition 25.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop blue color), 0.5 part of hydroxyethyl cellulose, comb-shaped high 0.4 parts of molecular dispersant [Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000], 2-pyridinethiol-1-oxide sodium salt [Lonza Japan Co., Ltd., trade name: sodium omadin] 0.5 part Then, 0.5 parts of polyvinyl alcohol, 15.0 parts of glycerin, 15.0 parts of xylitol, 0.2 part of antifoaming agent and 42.9 parts of water were mixed to obtain a reversible thermochromic aqueous ink composition.
The ink composition had a pH of 7.80 and a surface tension of 41.0 mN / m.

Production of filling-type writing instrument (see Fig. 5)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. It assembled in the connection state with the pen body 3 (bullet type), the cap 6 was mounted | worn, and the filling type writing instrument 1 (marking pen) was obtained.
The cap is formed by attaching SEBS resin as a friction member 7 on the top.

Blue letters (handwriting) were formed on the paper surface using the writing instrument.
The handwriting has a blue color at room temperature (25 ° C.), and when rubbed with a friction body attached to the cap, the handwriting is decolored and colorless, and this state is maintained at room temperature, By cooling to −20 ° C. or lower, the original blue color was restored, and the discoloration behavior was reproduced repeatedly.

Example 7
Preparation of reversible thermochromic microcapsule pigment (a) 4.5 parts of 2- (2-chloroamino) -6-dibutylaminofluorane as component (4), 4,4 '-(2-ethylhexane- 1,1-diyl) diphenol 3.0 parts, 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 5.0 parts, (ha) 4-benzyloxyphenylethyl caprate as component 50.0 A microcapsule pigment suspension containing a reversible thermochromic composition having color memory properties consisting of parts was obtained.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle diameter of 2.4 μm, a complete color erasing temperature of 56 ° C., a complete color development temperature of −20 ° C., and changes color from black to colorless according to temperature change.

Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop black color), 0.5 part of hydroxyethyl cellulose, comb-shaped high 0.4 parts of molecular dispersant [manufactured by Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000], 3-iodo-2-proponylbutylcarbamate [trade name: Glycasil 2000] produced by Lonza Japan Co., Ltd. 25 parts, polyhexamethylene biguanide [Lonza Japan Co., Ltd., trade name: Proxel IB] 0.25 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, sorbitol 15.0 parts, antifoaming agent 0. 2 parts of water and 42.9 parts of water were mixed to obtain a reversible thermochromic water-based ink composition.
The ink composition had a pH of 7.50 and a surface tension of 40.9 mN / m.

Production of filling-type writing instrument (see Fig. 5)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. The pen body 3 (cannonball type) was assembled in a connected state, and a cap 6 was attached to obtain a filling pen 1 (marking pen).
The cap is formed by attaching SEBS resin as a friction member 7 on the top.

A black character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting is black at room temperature (25 ° C.), and when rubbed with a friction body attached to the cap, the handwriting is decolored and colorless, and this state is maintained at room temperature, By cooling to −20 ° C. or lower, the original black color was restored, and the discoloration behavior was reproduced repeatedly.

Example 8
Preparation of reversible thermochromic microcapsule pigment (a) 4.5 parts of 2- (2-chloroamino) -6-dibutylaminofluorane as component (4), 4,4 '-(2-ethylhexane- 1,1-diyl) diphenol 3.0 parts, 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 5.0 parts, (ha) 4-benzyloxyphenylethyl caprate as component 50.0 A microcapsule pigment suspension containing a reversible thermochromic composition having color memory properties consisting of parts was obtained.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle diameter of 2.4 μm, a complete color erasing temperature of 56 ° C., a complete color development temperature of −20 ° C., and changes color from black to colorless according to temperature change.

Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop black color), 0.5 part of hydroxyethyl cellulose, comb-shaped high 0.4 parts of molecular dispersant [manufactured by Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000], 3-iodo-2-proponylbutylcarbamate [trade name: Glycasil 2000] produced by Lonza Japan Co., Ltd. 25 parts, 2-pyridinethiol-1-oxide sodium salt (Lonza Japan Co., Ltd., trade name: sodium omadin) 0.25 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, sorbitol 15.0 parts, A reversible thermochromic aqueous ink composition was obtained by mixing 0.2 part of an antifoaming agent and 42.9 parts of water.
The pH of the ink composition was 7.75, and the surface tension was 40.5 mN / m.

Preparation of a filling type writing instrument The ink composition is impregnated in an ink occlusion body in which a polyester sliver is coated with a synthetic resin film, and accommodated in a shaft tube made of polypropylene resin, and a polyester fiber is placed on the tip of the shaft tube through a holder. A resin-processed pen body (bullet type) was assembled in a connected state, and a cap was attached to obtain a filling pen (marking pen).

Preparation of writing instrument set A writing instrument set was obtained by combining the above-mentioned filling type writing instrument and a rectangular SEBS resin friction body.

A black character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting is black at room temperature (25 ° C.). When the character is rubbed with a friction body, the character is discolored and becomes colorless. This state is maintained at room temperature, and −20 By cooling to below ℃, the original black color was restored and the discoloration behavior was reproduced repeatedly.

Example 9
Preparation of reversible thermochromic microcapsule pigment (a) 4.5 parts of 2- (2-chloroamino) -6-dibutylaminofluorane as component (4), 4,4 '-(2-ethylhexane- 1,1-diyl) diphenol 3.0 parts, 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 5.0 parts, (ha) 4-benzyloxyphenylethyl caprate as component 50.0 A microcapsule pigment suspension containing a reversible thermochromic composition having color memory properties consisting of parts was obtained.
The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The microcapsule pigment has an average particle diameter of 2.4 μm, a complete color erasing temperature of 56 ° C., a complete color development temperature of −20 ° C., and changes color from black to colorless according to temperature change.

Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment (previously cooled to −20 ° C. or less to develop black color), 0.5 part of hydroxyethyl cellulose, comb-shaped high 0.4 parts of a molecular dispersant [manufactured by Nippon Lubrizol Co., Ltd., trade name: Solsperse 43000], 0.5 part of a nitrogen sulfur compound [manufactured by Hokuko Chemical Co., Ltd., trade name: Hokuside N100], polyvinyl alcohol 0 .5 parts, 15.0 parts of glycerin, 15.0 parts of xylitol, 0.2 part of antifoaming agent and 42.9 parts of water were mixed to obtain a reversible thermochromic water-based ink composition.
The ink composition had a pH of 7.30 and a surface tension of 40.2 mN / m.

Production of filling-type writing instrument (see Fig. 5)
The ink composition 2 impregnated with a polyester resin sliver covered with a synthetic resin film is impregnated with the ink composition, accommodated in a shaft tube 4 made of polypropylene resin, and a polyester fiber resin processed at the tip of the shaft tube through a holder 5. The pen body 3 (cannonball type) was assembled in a connected state, and a cap 6 was attached to obtain a filling pen 1 (marking pen).
The cap is formed by attaching SEBS resin as a friction member 7 on the top.

A black character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting is black at room temperature (25 ° C.), and when rubbed with a friction body attached to the cap, the handwriting is decolored and colorless, and this state is maintained at room temperature, By cooling to −20 ° C. or lower, the original black color was restored, and the discoloration behavior was reproduced repeatedly.

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

A black character (handwriting) was formed by writing on the paper using the writing instrument.
The handwriting is black at room temperature (25 ° C.). When the character is rubbed with a friction body, the character is discolored and becomes colorless. This state is maintained at room temperature, and −20 By cooling to below ℃, the original black color was restored and the discoloration behavior was reproduced repeatedly.

Comparative Example 1
Preparation of reversible thermochromic water-based ink composition 20.0 parts of reversible thermochromic microcapsule pigment prepared in Example 1 (previously cooled to -20 ° C. or less to develop a pink color), hydroxyethyl cellulose, 0. 5 parts, 0.5 parts of sodium dehydroacetate [manufactured by Taisho Technos Co., Ltd.], 0.5 parts of polyvinyl alcohol, 25.0 parts of glycerin, 0.2 part of antifoaming agent, and 53.3 parts of water are reversible. A thermochromic aqueous ink composition was obtained.
The ink composition had a pH of 6.30 and a surface tension of 41.0 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 1 were used to obtain filling-type writing tools (marking pens).

Comparative Example 2
Preparation of reversible thermochromic aqueous ink composition 20.0 parts of reversible thermochromic microcapsule pigment prepared in Example 1 (previously cooled to −20 ° C. or less to develop a pink color) 5 parts, 1,4 bis (3,3 '-(1-decylpyridinium) methyloxy) butane dibromide [manufactured by Taisho Technos Co., Ltd., trade name: Biocide NEO], 0.5 parts polyvinyl alcohol Then, 25.0 parts of glycerin, 0.2 part of antifoaming agent and 53.3 parts of water were mixed to obtain a reversible thermochromic aqueous ink composition.
The ink composition had a pH of 6.82 and a surface tension of 41.6 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 1 were used to obtain filling-type writing tools (marking pens).

Comparative Example 3
Preparation of reversible thermochromic aqueous ink composition 20.0 parts of reversible thermochromic microcapsule pigment prepared in Example 1 (previously cooled to −20 ° C. or less to develop a pink color), hydroxyethylcellulose 0. 5 parts, 1,4 bis (3,3 '-(1-decylpyridinium) methyloxy) butane dibromide [manufactured by Taisho Technos Co., Ltd., trade name: Biocide NEO], 0.5 parts polyvinyl alcohol Then, 15.0 parts of glycerin, 15.0 parts of sorbitol, 0.2 part of antifoaming agent and 48.3 parts of water were mixed to obtain a reversible thermochromic aqueous ink composition.
The ink composition had a pH of 6.82 and a surface tension of 41.6 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 1 were used to obtain filling-type writing tools (marking pens).

Comparative Example 4
Preparation of reversible thermochromic water-based ink composition 20.0 parts of reversible thermochromic microcapsule pigment prepared in Example 2 (previously cooled to −20 ° C. or less and colored yellow), hydroxyethylcellulose 0.5 Parts, polyhexamethylene biguanide [Lonza Japan Co., Ltd., trade name: Proxel IB] 0.5 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, xylitol 15.0 parts, antifoaming agent 0.2 Part and 48.3 parts of water were mixed to obtain a reversible thermochromic water-based ink composition.
The ink composition had a pH of 7.70 and a surface tension of 41.0 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 2 were used to obtain filling-type writing tools (marking pens).

Comparative Example 5
25.0 parts of reversible thermochromic microcapsule pigment prepared in Example 3 (previously cooled to −20 ° C. or less to develop orange color), 0.5 part of hydroxyethyl cellulose, potassium sorbate [Taisho Technos Co., Ltd. ), Product name: sorbic acid K / talacose] 0.5 parts, 0.5 parts of polyvinyl alcohol, 25.0 parts of glycerin, 0.2 parts of antifoaming agent, 48.3 parts of water are mixed and reversible thermal discoloration. Water-based ink composition was obtained.
The ink composition had a pH of 7.00 and a surface tension of 40.8 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 3 were used to obtain filling-type writing tools (marking pens).

Comparative Example 6
Preparation of reversible thermochromic water-based ink composition 25.0 parts of reversible thermochromic microcapsule pigment prepared in Example 3 (previously cooled to −20 ° C. or less to develop orange color), hydroxyethylcellulose 0.5 Parts, polyhexamethylene biguanide [Lonza Japan Co., Ltd., trade name: Proxel IB] 0.5 parts, polyvinyl alcohol 0.5 parts, glycerin 25.0 parts, antifoaming agent 0.2 parts, water 48.3 A reversible thermochromic water-based ink composition was obtained by mixing the parts.
The ink composition had a pH of 7.70 and a surface tension of 41.0 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 3 were used to obtain filling-type writing tools (marking pens).

Comparative Example 7
Preparation of reversible thermochromic water-based ink composition 25.0 parts of reversible thermochromic microcapsule pigment prepared in Example 3 (previously cooled to −20 ° C. or less to develop orange color), hydroxyethylcellulose 0.5 Parts, polyhexamethylene biguanide [Lonza Japan Co., Ltd., trade name: Proxel IB] 0.5 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, sorbitol 15.0 parts, antifoaming agent 0.2 Part and 43.3 parts of water were mixed to obtain a reversibly thermochromic water-based ink composition.
The ink composition had a pH of 7.65 and a surface tension of 42.2 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 3 were used to obtain filling-type writing tools (marking pens).

Comparative Example 8
Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment prepared in Example 4 (previously cooled to -20 ° C. or less and colored black), hydroxyethylcellulose 0.5 Parts, 3-iodo-2-proponylbutylcarbamate [Lonza Japan Co., Ltd., trade name: Glycacil 2000] 0.5 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, sorbitol 15.0 parts Then, 0.2 part of an antifoaming agent and 43.3 parts of water were mixed to obtain a reversible thermochromic water-based ink composition.
The pH of the ink composition was 6.70, and the surface tension was 40.3 mN / m.

Production of Filling-Type Writing Instruments Built-in writing tools similar to Example 4 were used to obtain filling-type writing tools (marking pens).

Comparative Example 9
Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment prepared in Example 5 (previously cooled to −20 ° C. or less to develop a blue color), 0.5% hydroxyethylcellulose Parts, didecyldimethylammonium propionate carbonate [Lonza Japan Co., Ltd., trade name: CARBOQUAT] 1.0 part, 0.5 parts polyvinyl alcohol, 15.0 parts glycerin, 15.0 parts sorbitol, antifoam A reversible thermochromic aqueous ink composition was obtained by mixing 0.2 part of the agent and 42.8 parts of water.
The ink composition had a pH of 7.60 and a surface tension of 41.5 mN / m.

Production of Filling-Type Writing Tool A filling-type writing tool (marking pen) was obtained by being built in the same writing tool as in Example 5.

Comparative Example 10
Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment prepared in Example 6 (previously cooled to −20 ° C. or less to develop a blue color), 0.5% hydroxyethylcellulose Parts, 2-pyridinethiol-1-oxide sodium salt [Lonza Japan Co., Ltd., trade name: sodium omadin] 0.5 parts, polyvinyl alcohol 0.5 parts, glycerol 15.0 parts, xylitol 15.0 parts, A reversible thermochromic aqueous ink composition was obtained by mixing 0.2 part of a foaming agent and 43.3 parts of water.
The ink composition had a pH of 7.70 and a surface tension of 41.6 mN / m.

Production of Filling Type Writing Tool A filling type writing tool (marking pen) was obtained by being incorporated in the same writing tool as Example 6.

Comparative Example 11
Preparation of reversible thermochromic aqueous ink composition 25.0 parts of reversible thermochromic microcapsule pigment prepared in Example 7 (previously cooled to −20 ° C. or less to develop black color), hydroxyethylcellulose 0.5 Part, 3-iodo-2-proponylbutylcarbamate [Lonza Japan KK, trade name: Glycacil 2000] 0.25 part, polyhexamethylene biguanide [Lonza Japan KK, trade name: Proxel IB] 0.25 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, sorbitol 15.0 parts, antifoaming agent 0.2 parts, and water 43.3 parts are mixed to prepare a reversible thermochromic aqueous ink composition. Obtained.
The ink composition had a pH of 7.38 and a surface tension of 40.2 mN / m.

Production of Filling Type Writing Tool A filling type writing tool (marking pen) was obtained by being built in the same writing tool as in Example 7.

Comparative Example 12
Preparation of reversible thermochromic water-based ink composition 25.0 parts of the reversible thermochromic microcapsule pigment prepared in Example 8 (previously cooled to -20 ° C. or less and colored black), hydroxyethylcellulose 0.5 Part, 3-iodo-2-proponylbutylcarbamate [Lonza Japan Co., Ltd., trade name: Glycasil 2000] 0.25 part, 2-pyridinethiol-1-oxide sodium salt [Lonza Japan Co., Ltd., Product name: sodium omadin] 0.25 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, sorbitol 15.0 parts, antifoaming agent 0.2 parts, and water 43.3 parts are mixed and reversible thermochromic. A water-based ink composition was obtained.
The pH of the ink composition was 7.62, and the surface tension was 40.1 mN / m.

Production of Filling Type Writing Tool A filling type writing tool (marking pen) was obtained by being built in the same writing tool as in Example 8.

Comparative Example 13
Preparation of reversible thermochromic aqueous ink composition 25.0 parts of the reversible thermochromic microcapsule pigment prepared in Example 9 (previously cooled to -20 ° C. or less to develop black color), 0.5 hydroxyethylcellulose Parts, nitrogen sulfur compound [Hokuko Chemical Co., Ltd., trade name: Hokuside N100] 0.5 parts, polyvinyl alcohol 0.5 parts, glycerin 15.0 parts, xylitol 15.0 parts, antifoaming agent 0. 2 parts of water and 43.3 parts of water were mixed to obtain a reversible thermochromic water-based ink composition.
The pH of the ink composition was 7.18, and the surface tension was 4.18 mN / m.

Production of Filled Writing Instruments Built in writing tools similar to Example 9 were used to obtain filled writing tools (marking pens).

The following tests were carried out using the writing instruments obtained in the respective examples and comparative examples.
Anti-mold test For each writing instrument, the kite used in JIS Z 2911 was added to the ink, and the situation inside the writing instrument when 90 days passed at 30 ° C. was confirmed.

Dispersion test over time of ink The inks prepared in Examples 1 to 9 and Comparative Examples 1 to 13 were placed in a 30 ml sample bottle, and the dispersion state of the capsule pigment in the ink in the sample bottle after standing at 50 ° C. for 30 days was confirmed. did.

Writing test over time Using each of the two writing instruments prepared in Examples 1 to 9 and Comparative Examples 1 to 13, 10 lines of 20 cm are written on a report sheet.
Put the cap on the writing instrument and keep it upright (the writing tip is upward), one is left at 25 ° C for 30 days, the other is left at 50 ° C for 30 days, then 10 lines of 20cm are written on the report paper It was compared with the handwriting before the test.

Vibration Test Using a writing instrument produced in Examples 1 to 9 and Comparative Examples 1 to 13, 10 lines of 20 cm are written on a report sheet.
Put the cap on the writing instrument, set it on a shaker (made by Taitec Co., Ltd., reciprocating shaker) in an upright state (writing tip upward), apply vibration at 284 rpm for 5 hours, 10 lines of 20 cm straight lines were written and compared with the handwriting before the test.

The test results are shown in the following table.

In addition, the evaluation regarding the symbol in a table | surface is as follows.
Anti-mold test ○: No generation of soot.
Δ: Slight wrinkle generated.

Dispersion test ○: The capsule pigment is uniformly mixed.
(Triangle | delta): The state in which a capsule pigment is a little hard to mix.
X: The state in which the capsule pigment is turned into a hard cake.

Written test ○: The handwriting is not faint compared to the initial, and the handwriting has the same color density as the initial.
X: Fading was observed at the start of writing, and the handwriting density was lighter than in the initial stage.

Vibration test ○: The handwriting is not faint compared to the initial, and the handwriting has the same color density as the initial.
X: Fading was observed at the start of writing, and the handwriting density was lighter than in the initial stage.

t ₁ Complete color development temperature of reversible thermochromic microcapsule pigment with heat decoloring type t ₂ Color development start temperature of reversible thermochromic microcapsule pigment with heat decoloration type t ₃ Reversible thermochromic microcapsule pigment with heat decoloration type Decoloration start temperature of t ₄ Complete decolorization temperature of reversible thermochromic microcapsule pigment of heat decoloring type T ₁ Complete decoloration temperature of reversible thermochromic microcapsule pigment of ₁ heating color developing type T ₂ Reversible heat of color developing type of heat decoloring type Discoloration start temperature of the color-changing microcapsule pigment T ₃ Color development start temperature of the reversible thermochromic microcapsule pigment of the ₃ heating color development type T ₄ Color development temperature of the reversible thermochromic microcapsule pigment of the heat development color type ΔH Hysteresis width 1 Writing instrument 2 Ink occlusion body 3 Pen body 4 Shaft cylinder 5 Holder 6 Cap 7 Friction member 8 Ink

Claims (9)

Encapsulating a reversible thermochromic composition comprising water and (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. A reversible thermochromic microcapsule pigment, a polymer flocculant selected from polyethylene oxide and water-soluble polysaccharides, and an acrylic having a plurality of carboxyl groups in the side chain as a comb-type polymer dispersant having a carboxyl group in the side chain Polymeric compound, water-soluble resin selected from alkyd resin, styrene maleic acid copolymer, polyvinylpyrrolidone, polyvinyl alcohol , sugar alcohol having 3 carbon atoms , sugar alcohol having 4 or more carbon atoms, and antiseptic having cationic property A reversible thermochromic water-based ink composition comprising an agent.   The reversibly thermochromic water-based ink composition according to claim 1, wherein a mass ratio of the comb polymer dispersant and the cationic preservative is 1: 1 to 1:10. One or more compounds wherein the cationic preservative is selected from a pyridinium compound, a biguanide compound, a chlorine quaternary ammonium salt compound, a non-chlorine quaternary ammonium salt compound, and a nonionic tertiary ammonium salt compound The reversible thermochromic water-based ink composition according to claim 1 or 2.   The reversible thermochromic water-based ink composition according to any one of claims 1 to 3, comprising a non-color-changing colorant.   A writing instrument comprising a pen body that houses the reversible thermochromic water-based ink composition according to any one of claims 1 to 4 in a shaft cylinder and derives the ink composition in the shaft cylinder.   The writing instrument according to claim 5, wherein the pen body has a rear end in contact with an ink occlusion body made of a fiber bundling body housed in a shaft cylinder, and the ink occlusion body is impregnated with an ink composition.   The writing instrument according to claim 5 or 6, wherein the pen body is a marking pen body.   The writing instrument according to any one of claims 5 to 7, comprising a friction member.   A writing instrument set comprising the writing instrument according to any one of claims 5 to 7 and a friction body.

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