JP2011178968A - Aqueous ink composition for ballpoint pen, ballpoint pen refill and ballpoint pen using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous ink composition for a ballpoint pen which has drought resistance of an ink composition formed using a pigment as a colorant and permanently creates excellent writing, and to provide ballpoint pen refills and ballpoint pens formed using the aqueous ink composition. <P>SOLUTION: There are provided an aqueous ink composition 6 for a ballpoint pen including at least a pigment, water, a thickener and an oligo saccharide in which D-glucosamine is β-1,4 bonded, a ballpoint pen refill 1 formed using the aqueous ink composition 6, and a ballpoint pen storing the ballpoint pen refill in a barrel. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a water-based ink composition for ballpoint pens, a ballpoint pen refill using the same, and a ballpoint pen. More specifically, even when the writing tip is left in the air for a long time, a water-based ink composition for ballpoint pens that has excellent drying resistance and suppresses the occurrence of scumming or inability to write due to drying of the pen tip and the same The present invention relates to a ballpoint pen refill and a ballpoint pen.

In recent years, pigment-based ballpoint pen ink compositions using pigments as colorants have been widely used, but pigment-based inks dry faster at the tip of the pen than inks using dyes, and the writing tip is in the air. There is a drawback that it is impossible to write if left for a long time.
In addition, water-based ballpoint pens have many so-called “gel ballpoint pens” in which ink containing a shear thinning agent as a thickener is directly stored in an ink storage tube. Ink used for this type of ballpoint pen is shearing. As a viscosity reducing agent, gums such as xanthan gum and succinoglycan, a cross-linked acrylic acid polymer, and the like are added. However, any of these shear thinning agents tends to form a strong dry film when moisture evaporates at the nib, and may reduce drying resistance (see, for example, Patent Document 1).
Therefore, in the pigment-based ballpoint pen ink composition to which the shear thinning agent is added, it is necessary to improve the drying resistance, and attempts have been made to increase the amount of the water-soluble organic solvent.
However, in an ink composition using a pigment as a colorant, a water-soluble organic solvent typified by a glycol solvent such as glycerin or ethylene glycol cannot obtain sufficient drying resistance. It tends to cause a problem that the viscosity is lowered and a good handwriting cannot be formed.

Japanese Patent Publication No. 5-54875

  The present invention solves the above problems, that is, provides a water-based ink composition for ballpoint pens excellent in drying resistance, a ballpoint pen refill using the same, and a ballpoint pen.

The present invention requires a water-based ink composition for ballpoint pens comprising at least a pigment, water, a thickener, and an oligosaccharide having D-1,4-glucosamine bonded to β-1,4.
Further, the ink composition contains 0.5 to 10.0% by mass of an oligosaccharide in which the D-glucosamine is β-1,4 bonded, and the pigment is (i) an electron-donating color-forming organic compound. (B) a microcapsule pigment in which a microcapsule encapsulates a reversible thermochromic composition comprising an electron-accepting compound and (c) a reaction medium for controlling the color reaction of (a) and (b). It is a requirement that the microcapsule pigment is contained in an amount of 10 to 50% by mass in the total amount of the ink composition.
Furthermore, the ballpoint pen refill in which the water-based ink composition for a ballpoint pen is accommodated in an ink accommodating tube, and a ballpoint pen tip having a ball rotatably held in the ink accommodating tube is mounted directly or via a connecting member, the ballpoint pen refill Is required to be a ballpoint pen in which the writing tip portion of the ballpoint pen refill is projected and retracted from the front end opening portion of the shaft cylinder by the operation of the retracting mechanism.

  The present invention relates to a water-based ink composition for ballpoint pens that is excellent in drying resistance in an ink composition using a pigment as a colorant and is capable of forming good handwriting permanently, and a ballpoint pen refill and ballpoint pen using the same. Can be provided.

It is a graph explaining the hysteresis characteristic in the color density-temperature curve of the microcapsule pigment used for this invention. It is explanatory drawing of the ball-point refill of one Example of this invention. FIG. 3 is an explanatory view showing a retractable ballpoint pen that accommodates the ballpoint refill of FIG. 2. FIG. 3 is an explanatory view showing a retractable ballpoint pen that accommodates the ballpoint refill of FIG. 2. FIG. 3 is an explanatory view showing a retractable ballpoint pen that accommodates the ballpoint refill of FIG. 2. It is explanatory drawing which shows the retractable ball-point pen which accommodated the several ball-point pen refill.

Examples of the oligosaccharide having D-1, glucosamine bonded to β-1,4 include chitosan oligosaccharide, which can impart excellent drying resistance and sag prevention performance.
The chitosan oligosaccharide can be obtained as a degradation product of chitosan, and consists of a mixture of disaccharide to heptasaccharide as a main component.
In order to impart dry resistance, it is necessary to form a dry film to some extent, but since monosaccharides do not have sufficient dry film formation, they have little effect on dry resistance and are applied to ballpoint pens because of their high water absorption. In this case, dripping is likely to occur when the chip is left facing down (inverted).
Furthermore, if a large amount of addition is attempted in order to obtain sufficient drying resistance, the water absorption increases and causes dripping, or the added sugar cannot be completely dissolved and the solid content in the ink increases, resulting in drying resistance. May decrease.
Since the saccharide has a characteristic that the hygroscopicity decreases as the molecular weight increases and a dry film is easily formed, D-glucosamine composed of a mixture of disaccharides to heptasaccharides as a main component has β-1,4 bonds. By using oligosaccharides, it is possible to prevent sagging under high humidity and to improve drying resistance.
In addition, oligosaccharides with β-1,4 bonds to D-glucosamine have a primary amine in the molecule, and therefore have the effect of improving the dispersibility of the pigment, and suppress unnecessary aggregation of pigments during film formation. And it is guessed that it has the function to form the dry film which has moderate intensity | strength in which a dry film is easily destroyed at the time of writing.
The oligosaccharide having β-1,4-bonded D-glucosamine is 0.5 to 10.0% by mass, preferably 1.0 to 8.0% by mass, more preferably 2.0 to the total amount of the ink composition. It is mix | blended in the range of -5.0 mass%. If the amount is less than 0.5% by mass, it is difficult to obtain the effect of drying resistance. If the amount is more than 10.0% by mass, the viscosity of the ink increases, which may cause crying or blurring, and may hinder followability. . Furthermore, drying resistance may be deteriorated.

Examples of the pigments include inorganic pigments such as carbon black and ultramarine blue, organic pigments such as copper phthalocyanine blue and benzidine yellow, synthetic resin fine particulate fluorescent pigments in which various fluorescent dyes are formed into a resin matrix, pearl pigments, metal powders Pigments, white pigments such as titanium dioxide, silica, calcium carbonate, reversible thermochromic pigments, and the like. All pigments that can be dispersed in an aqueous medium can be used. A reversible thermochromic composition comprising: (a) an electron-donating color-forming organic compound; (b) an electron-accepting compound; and (c) a reaction medium that controls the color reaction of (a) and (b) above. An encapsulated microcapsule pigment is preferably used.
The microcapsule pigment has a large hysteresis characteristic described in JP-A-2006-137886, JP-A-2006-188660, JP-A-2008-45062, JP-A-2008-280523, and the like. In other words, the shape of the curve plotting the change in color density due to temperature change is when the temperature is raised from the lower temperature side than the color change temperature range, and conversely when the temperature is lowered from the higher temperature side than the color change temperature range. The color changes following a very different route, and the color development state 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 ) is a specific temperature range [t microcapsule pigment obtained by encapsulating a reversible thermochromic composition having color-memorizing in a temperature range (substantially two-phase retaining temperature region)] between ₂ ~t ₃ is preferably used ( (See FIG. 1).

The hysteresis characteristic in the color density-temperature curve of the microcapsule pigment encapsulating the reversible thermochromic composition having color memory will be described.
In FIG. 1, the vertical axis represents color density and the horizontal axis represents temperature. The change in color density due to the temperature change proceeds along the arrow. Here, A is a point indicating a density at a temperature t ₄ (hereinafter referred to as a complete decoloring temperature) 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.

The complete decoloring temperature _{t 4,} the friction member and the temperature of decoloring than the frictional heat generated by rubbing between the writing surface, i.e., 50 ° C. to 90 ° C., preferably 55 to 85 ° C., more preferably 60-80 ° C. The complete color development temperature t ₁ is a temperature that can be obtained only in a freezing room, a cold region, or the like, that is, 0 ° C. or less, preferably −50 to −5 ° C., more preferably −50 to −10 ° C. It is preferable that it exists in.

Examples of the compounds for the components (a), (b) and (c) will be given 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-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,
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,
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,
And 3 ', 6'-bis [phenyl (3-ethylphenyl) amino] -spiro [isobenzofuran-1 (3H), 9'-[9H] xanthen] -3-one.
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.

(B) Component electron-accepting compounds include active proton-containing compounds, pseudo-acidic compounds (compounds that are not acids but act as acids in the composition to cause component (I) 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.

〔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。 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.
As the component (c), a compound represented by the following general formula (1) can be used.

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

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

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

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

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

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

（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.

  The mixing 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. (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).

  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. Furthermore, the surface of the microcapsule pigment can be provided with a secondary resin film according to the purpose to impart durability, or the surface characteristics can be modified for practical use.

The microcapsule pigment may have a circular cross section or a non-circular cross section.
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.
The capsule pigment has a light color density at the time of coloring of the reversible thermochromic composition contained in comparison with general dyes and pigments, so a large amount of microcapsule pigment is added to obtain a good color density handwriting. There is a need to.
The microcapsule pigments may be used alone or in combination of two or more, and used in the ink composition in the range of 10 to 50% by mass, preferably 15 to 45% by mass, more preferably 20 to 45% by mass. It is done.

The solvent used in the ink may be only an organic solvent, but 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.
In addition, when using a microcapsule pigment encapsulating a reversible thermochromic composition as a pigment, by not containing a glycol-based water-soluble organic solvent in the water-based ink composition, ink follow-up failure due to an increase in ink viscosity, Problems such as poor drying of handwriting and bleeding of handwriting can be prevented.

By adding the thickener, aggregation and sedimentation of the pigment can be suppressed and bleeding of the handwriting can be suppressed.
Furthermore, when the ink composition is filled into the ballpoint pen, ink leakage from the gap between the ball and the tip when not in use is prevented, or the ink backflow occurs when the writing tip is left facing upward (upright state). Can be prevented.
As the thickener, a general-purpose compound is used, and among them, a shear thinning agent that causes shear thinning is preferably used.
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 Gelation ability extracted from seaweeds such as ditantan gum, hydroxyethyl cellulose, alginic acid alkyl esters, polymers with a molecular weight of 100,000 to 150,000 based on alkyl esters of methacrylic acid, glucomannan, agar and carrageenan Thickening polysaccharides, 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 fat Nonionic surfactants having an HLB value of 8 to 12, such as esters, polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, fatty acid amides, salts of dialkyl or dialkenyl sulfosuccinic acids, N-alkyl Examples thereof include a mixture of -2-pyrrolidone and an anionic surfactant, and a mixture of polyvinyl alcohol and an acrylic resin.

Further, if necessary, an alkyd resin, an acrylic resin, a styrene maleic acid copolymer, a cellulose derivative, polyvinyl pyrrolidone, polyvinyl alcohol or the like may be added for fixing to the paper surface or imparting viscosity.
Furthermore, various additives can be added as necessary.
Examples of the additive include higher fatty acids such as oleic acid, nonionic surfactants having a long chain alkyl group, polyether-modified silicone oil, thiophosphite tri (alkoxycarbonylmethyl ester) and thiophosphite tri (alkoxycarbonylethyl ester). ), Etc., phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers, phosphoric acid diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers, or metal salts thereof It is preferable to add a lubricant such as an ammonium salt, an amine salt, or an alkanolamine salt to prevent wear of the ball seat.
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- Preservatives or antifungal agents such as (methylsulfonyl) pyridine, ascorbic acid, ascorbic acid derivatives, natural or synthetic polyphenols, N-vinylpyrrolidone oligomers, kojic acid, hydroxylamines, oxime derivatives, α-glucosylrutin, Oxygen absorbers such as sulfonate, phosphinate, sulfite, sulfoxylate, dithionite, thiosulfate, thiourea dioxide, formamidinesulfinic acid, glutathione, a reaction product of n-butyraldehyde and aniline, You may add an antifoamer, a dispersing agent, etc.

The ballpoint pen tip is a ball holder formed by cutting with a tip holding a ball in a ball holding portion formed by pressing and deforming the vicinity of the tip of a metal pipe inward from the outer surface, a metal material drill or the like. Examples include a chip holding a ball in the holding portion, a chip holding a ball by providing a resin ball receiving seat inside a metal or plastic molded body, and the like.
The tip may be configured to bias the ball forward by a spring body.
The ball may be about 0.1 to 3.0 mm in diameter, such as cemented carbide, stainless steel, ruby, ceramic, resin, rubber, etc., preferably 0.3 to 1.5 mm, more preferably 0. 3 to 1.0 mm are used.

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 that stores the ink composition.
The ball-point pen tip and the ink containing tube are fitted directly or via a connecting member, and a ball-point pen refill is formed by filling the ink composition and, if necessary, the ink backflow prevention body composition.

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.
It is preferable to add a gelling agent to the nonvolatile liquid and / or the hardly volatile liquid to increase the viscosity to a suitable viscosity. The surface of the silica is hydrophobized, the surface is methylated fine particle silica, and aluminum silicate. , Swellable mica, hydrophobic thickeners such as bentonite and montmorillonite, fatty acid metal soaps such as magnesium stearate, calcium stearate, aluminum stearate, zinc stearate, tribenzylidene sorbitol, fatty acid amide, amide modified Examples include dextrin compounds such as polyethylene wax, hydrogenated castor oil, fatty acid dextrin, and cellulose compounds.
Furthermore, the liquid ink backflow prevention body composition and a solid backflow prevention body can be used in combination.

The tip of the ballpoint pen tip can be fixed with a resin film for preventing the tip of the tip from drying, and the tip of the tip of the ball, the ball holding portion, and the gap between the ball and the ball holding portion are fixed. As a result, it is possible to prevent the tip of the tip from drying and volatilization of the medium in the ink.
As the resin for forming the resin film, a thermoplastic resin, a thermosetting resin, or an ultraviolet curable resin is used.

The ballpoint pen refill can be accommodated in a shaft tube to obtain a cap-type ballpoint pen.
Further, the ballpoint pen refill can be accommodated in a shaft cylinder to obtain a retractable ballpoint pen. The ballpoint pen refill is stored in the shaft cylinder with the tip exposed to the outside air, and the operation of the retracting mechanism is performed. Thus, the writing tip protrudes from the shaft tube opening.
Examples of the appearance mechanism include a knock type, a rotary type, and a slide type.
The knock type has a knock portion on the rear end portion of the shaft tube and the side surface of the shaft tube, and by pressing the knock portion, the writing tip portion of the ballpoint pen refill is projected and retracted from the front end opening portion of the shaft tube, or on the shaft tube. A configuration in which the writing tip portion of the ballpoint pen refill is projected and retracted from the front end opening portion of the shaft cylinder by pressing the provided clip portion can be exemplified.
The rotary type has a rotating part at the rear part of the shaft cylinder, and can be exemplified by a configuration in which the writing tip part of the ballpoint pen refill is projected and retracted from the front end part of the shaft cylinder by turning the rotating part.
The slide type has a slide part on the side surface of the shaft cylinder, and the sliding tip of the writing point of the ballpoint pen refill is projected and retracted from the front end opening of the shaft cylinder by operating the slide, or the clip part provided on the shaft cylinder is slid. By doing so, it is possible to exemplify a configuration in which the writing tip portion of the ballpoint pen refill is projected and retracted from the opening at the front end of the shaft cylinder.
The retractable ballpoint pen is a compound type retractable ballpoint pen in which a plurality of ballpoint pen refills are accommodated in a shaft cylinder, and the writing tip of one of the ballpoint pen refills protrudes and retracts from the opening at the front end of the shaft cylinder by operation of the retractable mechanism. May be.

The ball pen refill filled with ink containing the reversible thermochromic pigment and the handwriting formed by the ball pen containing the refill can be decolored by applying a friction member.
As the friction member, an elastic body such as an elastomer or plastic foam which is rich in elasticity and can generate frictional heat by generating appropriate friction during friction is suitable.
Although the handwriting can be rubbed using an eraser, the above-mentioned friction member is preferably used because erase scraps are generated at the time of friction.
As the material of the friction member, silicone resin, SEBS resin (styrene ethylene butadiene styrene block copolymer), polyester resin, or the like is used.
The friction member can be obtained by combining a ball-point pen and a member of arbitrary shape (friction body) separately to obtain a ball-point pen set, but is excellent in portability by fixing the friction member to the ball-point pen.
In the case of a ballpoint pen equipped with 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 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 ballpoint pen, the location where the friction member is provided is not particularly limited, but for example, the shaft cylinder itself is formed by a friction member, or when the clip is provided, the clip itself is formed by 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 will be described below, but the present invention is not limited to these examples. In addition, a numerical value represents a mass part.

Example 1
Preparation of microcapsule pigment (a) 4,5,6,7-tetrachloro-3- [4- (diethylamino) -2-methylphenyl] -3- (1-ethyl-2-methyl-1H-indole) as component -3-yl) -1 (3H) -isobenzofuranone 2.0 parts, (b) component 4,4 '-(2-ethylhexane-1,1-diyl) diphenol 3.0 parts, A reversible thermochromic composition having color memory composed of 5.0 parts of 2-bis (4′-hydroxyphenyl) -hexafluoropropane and 50.0 parts of 4-benzyloxyphenylethyl caprate as component (c) An encapsulated microcapsule pigment suspension was obtained.
The suspension was centrifuged to isolate the microcapsule pigment.
The microcapsule pigment has an average particle size of 1.8 μm, a complete color erasing temperature of 55 ° C., and a complete color development temperature of −20 ° C., which changes from blue to colorless according to the temperature change.
The microcapsule pigment (cooled in advance to −20 ° C. or less to cause the microcapsule pigment to develop a blue color) was used as a colorant.

Preparation of water-based ink composition for ballpoint pen The ink composition is shown in the following table. The numerical value of a composition in a table | surface represents a mass part.

The contents of the raw materials in the table will be described below according to the note numbers.
(1) Product name: Leozan, manufactured by Sanki Co., Ltd., shear thinning agent (2) Product name: COS-YS, manufactured by Yaizu Suisan Chemical Co., Ltd. (3) Product name: SANDEC 300, Sanwa Starch Kogyo Co., Ltd., sugar mixture containing 29% starch saccharified product of 8 or more sugars (4) Trade name: NA-COS-Y, Yaizu Suisan Kogyo Co., Ltd., N-acetylglucosamine is β-1,4 Bound oligosaccharide (5) Product name: Prisurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Phosphate ester surfactant (6) Product name: Proxel XL-2, manufactured by Avicia Co., Ltd. -Benzthiazoline-3-one

Preparation of ball-point pen refill Each ink composition 6 is sucked and filled into an ink containing tube 5 made of polypropylene resin, and the vicinity of the tip of a metal pipe is pressed and deformed inward from the outer surface through a resin connection member (holder) 4. The ball holding portion formed in this manner was connected to a ballpoint pen tip 2 holding a stainless steel ball 3 having a diameter of 0.7 mm.
Next, an ink backflow preventer (liquid stopper) was filled from the rear end of the polypropylene pipe, and a tail plug was fitted to the rear part of the pipe to obtain a ballpoint refill 1.
The following tests were performed using the ballpoint pen refill.

Drying resistance test A ballpoint pen refill that has been confirmed to be writable can be left standing at room temperature (25 ° C) and in a 50 ° C constant temperature bath for 60 days with the pen tip exposed, and then handwritten on writing paper. Circles of 12 were written continuously in one line, and from what line the writing was normally performed was examined and evaluated according to the following criteria.
○: Can write normally from the first line.
Δ: Normal writing can be made within the third line.
X: Four or more lines are required for normal writing, or writing is not possible.

The results of the drying resistance test are shown in the following table.

Production of Ballpoint Pen The ballpoint refill obtained in Example 1 was incorporated into the shaft cylinder 8 to obtain the retractable ballpoint pen 7 (see FIG. 3).
The retractable ballpoint pen is housed in the shaft cylinder in a state where the writing tip provided on the ballpoint pen refill is exposed to the outside air, and a retractable mechanism (knock mechanism) provided at the rear end of the shaft cylinder. It is a structure in which the writing tip protrudes from the opening at the front end of the barrel by operation.
The initial handwriting obtained by writing in a state where the ballpoint pen tip was projected and retracted from the opening at the front end of the barrel by the operation of the retracting mechanism was blue.
The handwriting can be decolored by rubbing using a friction member 9 made of SEBS resin provided around the opening of the shaft tube tip.

Production of Ballpoint Pen The ballpoint refill obtained in Example 2 was incorporated into the shaft tube 8 to obtain a retractable ballpoint pen 7 (see FIG. 4).
The retractable ballpoint pen is housed in the shaft cylinder with the writing tip provided on the ballpoint pen refill exposed to the outside air, and a clip-shaped retracting mechanism (slide mechanism) provided on the side surface of the shaft cylinder. Is a structure in which the writing tip protrudes from the opening at the front end of the shaft cylinder.
The initial handwriting obtained by writing in a state where the ballpoint pen tip was projected and retracted from the opening at the front end of the barrel by the operation of the retracting mechanism was blue.
In addition, the said handwriting can be decolored by rubbing using the friction member 9 made from SEBS resin provided in the rear-end part of the axial cylinder.

Production of Ballpoint Pen The ballpoint refill obtained in Example 3 was incorporated into the shaft tube 8 to obtain a retractable ballpoint pen 7 (see FIG. 5).
The retractable ballpoint pen is housed in the shaft cylinder in a state where the writing tip provided on the ballpoint pen refill is exposed to the outside air, and by the operation of the retracting mechanism (knock mechanism) provided at the rear portion of the shaft cylinder. This is a structure in which the writing tip protrudes from the opening at the front end of the barrel.
The initial handwriting obtained by writing in a state where the ballpoint pen tip was projected and retracted from the opening at the front end of the barrel by the operation of the retracting mechanism was blue.
In addition, the said handwriting can be decolored by rubbing using the friction member 9 made from SEBS resin provided in the intrusion mechanism.

Preparation of Ballpoint Pen Refill The ink composition of Example 1 is sucked and filled into an ink containing tube made of polypropylene resin, and connected to a ballpoint pen tip holding a stainless steel ball having a diameter of 0.5 mm through a resin connection member (holder). An ink backflow prevention body (liquid stopper) was filled from the rear end of the polypropylene pipe.
Next, an operation body having the same color as each ink composition was fitted to the rear part of the ink containing tube to obtain a refill for ballpoint pen.

Preparation of ballpoint pen refill The ink composition of Example 1 is sucked and filled into an ink containing tube made of polypropylene resin, and connected to a ballpoint pen tip holding a stainless steel ball having a diameter of 0.4 mm via a resin connection member (holder). An ink backflow prevention body (liquid stopper) was filled from the rear end of the polypropylene pipe.
Next, an operation body having the same color as each ink composition was fitted to the rear part of the ink containing tube to obtain a refill for ballpoint pen.

Ballpoint pen production (see Fig. 6)
The two refills for the ballpoint pen obtained as described above are incorporated into a transparent shaft 8 (diameter 11 mm) having a lid 10 that can be opened and closed at the rear, and after closing the lid, The retractable ball-point pen 7 in which the writing tip portion of any of the refills for the ballpoint pen protrudes and retracts from the front end opening portion of the shaft cylinder by operation is obtained.
A friction member 9 made of SEBS resin is provided in the vicinity of the opening at the tip of the shaft cylinder.
The initial handwriting obtained by writing in a state where the ballpoint pen tip was projected and retracted from the opening at the front end of the barrel by the operation of the retracting mechanism was blue.
The handwriting can be decolored by rubbing with a friction member.

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 Complete decoloring temperature 1 Ballpoint pen refill 2 Ballpoint pen tip 3 Ball 4 Connection member 5 Ink receiving tube 6 Ink composition 7 Retractable ballpoint pen 8 Shaft cylinder 9 Friction member 10 Lid

Claims (8)

  A water-based ink composition for ballpoint pens comprising at least a pigment, water, a thickener, and an oligosaccharide in which D-glucosamine is β-1,4-bonded.   The water-based ink composition for a ballpoint pen according to claim 1, wherein the ink composition contains 0.5 to 10.0% by mass of an oligosaccharide in which the D-glucosamine is β-1,4 bonded.   Reversible thermal discoloration in which the pigment comprises (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium that controls the color reaction of (a) and (b). The water-based ink composition for a ballpoint pen according to claim 1 or 2, which is a microcapsule pigment in which a functional composition is encapsulated in a microcapsule.   The aqueous ink composition for ballpoint pens according to claim 3, wherein the microcapsule pigment is contained in an amount of 10 to 50% by mass based on the total amount of the ink composition.   The water-based ink composition for a ballpoint pen according to any one of claims 1 to 4 is accommodated in an ink storage tube, and a ballpoint pen tip that rotatably holds the ball in the ink storage tube is directly or via a connecting member. A ballpoint pen refill.   6. A ballpoint pen in which the ballpoint pen refill according to claim 5 is accommodated in a shaft cylinder provided with a retracting mechanism, and a writing tip portion of the ballpoint pen refill appears and disappears from the front end opening of the shaft cylinder by the operation of the retracting mechanism.   The ballpoint pen according to claim 6, wherein a plurality of ballpoint pen refills are accommodated in the shaft cylinder, and a writing tip portion of any of the ballpoint pen refills protrudes and retracts from the front end opening portion of the shaft cylinder by the operation of the projecting and retracting mechanism.   The ballpoint pen according to claim 6 or 7, comprising a friction member.

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