JP7050522B2 - Oil-based ballpoint pen - Google Patents

Description

The present invention relates to an ink composition for an oil-based ballpoint pen and an oil-based ballpoint pen using the same.

Conventionally, unlike other types of writing instruments, ballpoint pens consist of a metal tip made of stainless steel or the like at the tip and a transfer ball made of a metal such as super steel held in the ball receiving seat of the metal tip. However, there is a problem that the ball-point pen is worn due to the rotation of the ball during writing, line skipping and blurring occur in the writing stroke, and the writing quality deteriorates.

In order to solve these problems, many ink compositions for oil-based ballpoint pens using various lubricants have been proposed for the purpose of improving the lubricity between the ball and the ball seat of the ballpoint pen tip.

As an ink composition for an oil-based ballpoint pen using such a lubricant, as an ink composition for an oil-based ballpoint pen, the one using an alkyl β-D-glucoside is JP-A-5-331403 “Oil-based ballpoint pen ink”, which has an average molecular weight of 200 to 4000,000. As a material using a certain polyethylene glycol, Japanese Patent Application Laid-Open No. 7-196971 “Ink Composition for Oil-based Ballpoint Pen”, N-acylamino acid, N-acylmethyltauric acid, and N-acylmethylalanine are used. Japanese Unexamined Patent Publication No. 2007-176995, "Ink for oil-based ballpoint pens", and Patent No. 3500552, "Oil-based ink composition for ballpoint pens", which uses a phosphate ester, are disclosed.

"Japanese Patent Laid-Open No. 5-331403" "Japanese Patent Laid-Open No. 7-196971" "Japanese Patent Laid-Open No. 2007-176995" "Patent No. 3500552 Gazette"

However, when various lubricants such as those in Patent Documents 1 to 4 are used, it is possible to suppress the wear of the ball seat while improving the writing quality to some extent, but the lubricity is not satisfactory and there is room for improvement. was there. Further, recently, when writing on copy paper, the writing pressure is higher than usual (high writing pressure writing), so that it is required to further improve the lubricity and the high writing pressure writing performance. .. Further, an ink composition for an oil-based ballpoint pen that improves the writing performance when the tip tip is left in the atmosphere when the tip is dried is also desired, and in particular, a knock-type oil-based ballpoint pen or a rotary feeding-type oil-based ink composition is desired. When a haunting type oil-based ballpoint pen such as a ballpoint pen is used, it is important because the writing performance is likely to be affected.

An object of the present invention is to obtain an ink composition for an oil-based ballpoint pen, which improves lubricity, suppresses wear of the ball seat and improves writing quality, and has good ink stability over time, and an oil-based ballpoint pen using the same. ..

２．前記酸性リン酸エステルの末端アルキル基（ｌ、ｍ）が、１～１０であることを特徴とする第１項に記載の油性ボールペン用インキ組成物。
３．前記酸性リン酸エステルの含有量が、インキ組成物全量に対して、０．１～１０．０質量％であることを特徴とする第１項または第２項に記載の油性ボールペン用インキ組成物。
４．前記油性ボールペン用インキ組成物に、ＨＬＢ値が６～１４の界面活性剤を含んでなることを特徴とする第１項ないし第３項のいずれか１項に記載の油性ボールペン用インキ組成物。
５．前記油性ボールペン用インキ組成物に、脂肪酸エステルを含んでなることを特徴とする請求項１ないし４のいずれか１項に記載の油性ボールペン用インキ組成物。
６．前記油性ボールペン用インキ組成物に、さらに造塩染料を含んでなることを特徴とする第１項ないし第５項のいずれか１項に記載の油性ボールペン用インキ組成物。
７．２０℃、剪断速度５ｓｅｃ^－１におけるインキ粘度が、３００００ｍＰａ・ｓ以下であることを特徴とする第１項ないし第６項のいずれか１項に記載の油性ボールペン用インキ組成物。
８．インキ収容筒の先端部に、ボールを回転自在に抱持したボールペンチップを有し、前記インキ収容筒内に第１項ないし第７項のいずれか１項に記載の油性ボールペン用インキ組成物を収容してなることを特徴とする油性ボールペン。」とする。 In order to solve the above problems, the present invention comprises "1. a pigment, an organic solvent, an acidic phosphoric acid ester, an organic amine which is a secondary amine or a tertiary amine, and the acidic phosphoric acid ester has a general formula (1). An ink composition for an oil-based ball pen, which is 1) or (2).

2. 2. The ink composition for an oil-based ballpoint pen according to Item 1, wherein the terminal alkyl group (l, m) of the acidic phosphoric acid ester is 1 to 10.
3. 3. The ink composition for an oil-based ballpoint pen according to Item 1 or 2, wherein the content of the acidic phosphoric acid ester is 0.1 to 10.0% by mass with respect to the total amount of the ink composition. ..
4. The ink composition for an oil-based ballpoint pen according to any one of Items 1 to 3, wherein the ink composition for an oil-based ballpoint pen contains a surfactant having an HLB value of 6 to 14.
5. The ink composition for an oil-based ballpoint pen according to any one of claims 1 to 4, wherein the ink composition for an oil-based ballpoint pen contains a fatty acid ester.
6. The ink composition for an oil-based ballpoint pen according to any one of Items 1 to 5, wherein the ink composition for an oil-based ballpoint pen further contains a salt-forming dye.
7. The ink composition for an oil-based ballpoint pen according to any one of Items 1 to 6, wherein the ink viscosity at 20 ° C. and a shear rate of 5 sec ^-1 is 30,000 mPa · s or less.
8. A ballpoint pen tip that rotatably holds a ball is provided at the tip of the ink containing cylinder, and the ink composition for an oil-based ballpoint pen according to any one of items 1 to 7 is placed in the ink containing cylinder. An oil-based ballpoint pen that is characterized by being housed. ".

The present invention improves lubricity, suppresses wear of the ballpoint pen and improves writing quality, and in particular, improves lubricity under high writing pressure (writing load 300 to 500 gf), and is oil-based with good ink stability over time. An ink composition for a ballpoint pen and an oil-based ballpoint pen using the same could be obtained.

The feature of the present invention is an ink composition for an oil-based ballpoint pen, which comprises an acidic phosphoric acid ester represented by the general formula (Chemical formula 1) or (Chemical formula 2), an organic amine which is a secondary amine or a tertiary amine, and a pigment. It is to make things. It contains an acidic phosphate ester of the general formula (Chemical formula 1) or (Chemical formula 2) and an organic amine which is a secondary amine or a tertiary amine to stabilize the neutralization and stabilize the ink with time. By making it good, the lubricity is improved by the lubricating layer made of the acidic phosphoric acid ester, and by using a pigment in combination, the lubricity between the ball and the chip body is maintained, and the writing pressure is high (writing load 300). It is possible to maintain lubricity even at ~ 500 gf), suppress wear of the ball seat, and improve writing quality.

(Acid phosphate ester)
The acidic phosphoric acid ester used in the present invention is represented by the following general formulas (Chemical formula 1) and (Chemical formula 2), and is neutralized and stabilized with a secondary amine or a tertiary amine as an organic amine. By improving the stability over time of the ink, the lubrication layer by the acidic phosphoric acid ester improves the lubricity, and further improves the lubricity under high writing pressure (writing load 300 to 500 gf), and the ball seat. It is possible to suppress wear and improve the writing quality. This is because when an acidic phosphoric acid ester is used, the effect of the acidic phosphoric acid ester is achieved by neutralizing the acidic phosphoric acid ester with a secondary amine or a tertiary amine to stabilize the solution in the ink. This is to make it easier to obtain. Regarding the reactivity in oil-based inks, the primary amine is the strongest, followed by the secondary amine and the tertiary amine, and the primary amine is the acidic phosphate ester, colorant and others. It is easy to react with the components of, and it is easy to affect the stability of the ink over time. Therefore, it is preferable to use a secondary amine or a tertiary amine, and more preferably, a tertiary amine is used.

In the acidic phosphoric acid esters of the general formulas (Chemical formula 1) and (Chemical formula 2), P having the structure of the general formulas (Chemical formula 1) and (Chemical formula 2) is adsorbed on the metal ball pen tip body or the ball and becomes P. By forming a lubricating layer with adjacent alkoxyethyl groups (Cl H _{2l + 1} OCH ₂ CH ₂ O) and alkoxyl groups ( _Cm H _{2m + 1} O), lubricity is improved, and wear suppression and writing quality of the ball seat are suppressed. It is possible to improve. In particular, unlike conventional phosphate esters, it has an alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O) and an alkoxy group (C _m H _{2m + 1} O) to form a lubricating layer with higher lubricity. Therefore, it is possible to maintain lubricity even under high writing pressure (writing load 300 to 500 gf), suppress wear of the ball seat even under high writing pressure (writing load 300 to 500 gf), and improve writing quality. It is effective. In particular, considering that the wear of the ball seat is suppressed and the writing quality is improved even under high writing pressure (writing load 300 to 500 gf), a general formula having an alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O) is used. It is preferable to use (Chemical formula 1).

Further, among the acidic phosphate esters of the general formulas (Chemical formula 1) and (Chemical formula 2), the terminal alkyl of the alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O) and the alkoxyl group (C _m H _{2 m + 1} O). It is preferable that the carbon chain (l, m) of the group is a specific carbon chain (l, m), but this effect is presumed as follows.
The carbon chain (l, _m ) of the terminal alkyl group of the alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O) and the alkoxyl group (Cm H _{2m + 1} O) is preferably 1 to 10. This is because the carbon chain of the terminal alkyl group of the alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O) and the alkoxyl group (C _n H _{2n + 1} O) becomes too long, and the writing feeling and writing performance are good. , It is difficult to suppress wear of the ball seat under high writing pressure (writing load 300 to 500 gf). This is because when the carbon chain (l, m) of the terminal alkyl group exceeds 10, especially when the carbon chain (l, m) is 5 or less, steric damage is likely to occur between the carbon chains. Even if the phosphate groups adsorbed on the metal become dense, the arrangement of carbon chains is difficult to become dense, a lubricating layer with sufficient lubricity cannot be obtained, and it is difficult to suppress wear of the ball seat under high writing pressure. Because. Furthermore, since the polarity of the terminal alkyl group shifts to the oily side, the affinity for organic solvents is inferior, which tends to affect the dissolution stability, especially the glycol ether solvent, which tends to affect the dissolution stability in the ink. Sexual problems are more likely to occur. For this reason, metal salt precipitates are likely to be generated due to the influence of metal ions and the like in the metal chip due to long-term storage, the stability over time of the ink is likely to be inferior, and it is difficult to obtain the lubricating effect as in the present invention. Therefore, the carbon chain (l, m) of the terminal alkyl group is preferably 1 to 10, and more considered, the carbon chain (l, m) of the terminal alkyl group is 1 to 5. Is preferable.
On the other hand, when the carbon chain (l, m) of the terminal alkyl group is 3 or less, the wear suppression of the ball seat under high writing pressure is good, but the alkyl group does not sufficiently extend in the ink. Since the lubricating layer has insufficient cushioning between the ball and the ball seat, the writing quality and writing performance are likely to be affected. Therefore, by using butoxyethyl acid phosphate (l = 4), butyl acid phosphate (m = 4) or the like having a butyl group (carbon chain of the terminal alkyl group: 4) as the terminal alkyl group, under high writing pressure. This is preferable because it is easy to obtain the effects of suppressing wear of the ball seat and improving writing quality and writing performance.

Further, for acidic phosphate esters such as the general formulas (Chemical formula 1) and (Chemical formula 2), monoesters of acidic phosphate esters (n = 1 of Chemical formulas 1 and 2) and diesters of acidic phosphate esters (Chemical formulas). 1. n = 2) of Chemical formula 2, a triester of an acidic phosphoric acid ester (n = 3 of Chemical formula 1 and Chemical formula 2), a mixture thereof, and the like can be mentioned. Among them, considering the suppression of wear of the ball seat even under high writing pressure (writing load 300 to 500 gf) and the writing taste, the acid phosphate ester monoester (n = 1 of chemical 1 and chemical 2). , It is preferable to use a mixture of acid phosphate diesters (chemical 1, chemical 2 n = 2), which is the acid phosphate triester (chemical 1, chemical 2 n = 3). This is because too many alkoxyethyl groups (Cl H _{2l + 1} OCH ₂ CH ₂ O) and alkoxyl groups ( _Cm H _{2m + 1} O) tend to affect the stability of the ink over time.
Further, considering the lubricity even under the above high writing pressure (writing load 300 to 500 gf), the mixing ratio of the monoester of the acidic phosphoric acid ester and the diester of the acidic phosphoric acid ester is acidic. When a diester of a phosphoric acid ester (n = 2 of chemical 1 and chemical 2) is used, there are many alkoxyethyl groups (Cl H _{2l + 1} OCH ₂ CH ₂ O) and alkoxyl groups (C _m H _{2m + 1} O), so that lubricity is good. It is preferable to have a large amount of acid phosphate diester because it works in an advantageous manner and further maintains the stability over time of the ink. Therefore, the range of 1: 1 to 1: 5 is preferable, and if further considered, the range of 1: 1 to 1: 3 is preferable.

Further, regarding the acidic phosphoric acid ester having the alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O) of the general formula (Chemical formula 1), as an example, in the polyoxyethylene phosphoric acid ester-based surfactant, a plurality of ethylenes are used. By having an oxide group, the alkyl group and the ethylene oxide group repel each other, the alkyl group does not easily extend linearly in the ink, and the writing performance is good, but the hydrophobic group of the phosphoric acid ester adsorbed on the metal. Since the esters do not line up closely, the lubricity, especially under high writing pressure, tends to be inferior. For this reason, having an alkoxy group and one ethylene oxide group, such as an alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O), is different from the conventional structure having a plurality of ethylene oxide groups. , It is preferable to use the general formula (Chemical formula 1) because a remarkable lubricating effect can be obtained, and in particular, a butyl acid having a butoxyethyl group (C ₄ H ₉ OCH ₂ CH ₂ O, carbon chain 4 of a terminal alkyl group). Phosphate is preferred.

Further, as specific examples of acidic phosphoric acid esters such as the general formulas (Chemical formula 1) and (Chemical formula 2), the general formula (Chemical formula 1) is butoxyethyl acid phosphate (l = 4) and the like, and (Chemical formula 2) is Methyl acid phosphate (m = 1), ethyl acid phosphate (m = 2), butyl acid phosphate (m = 4), 2-ethylhexyl acid phosphate (m = 8), isodecyl acid phosphate (m = 10), lauryl acid Phosphate (m = 12), Alkyl (m = 12, 14, 16, 18) Acid Phosphate, Isotridecyl Acid Phosphate (m = 13), Oleyl Acid Phosphate (m = 18), Tetracosyl Acid Phosphate (m =) 24) and the like.

The content of the acidic phosphoric acid ester is more preferably 0.1 to 10.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, it tends to be difficult to obtain the desired lubricity, and if it exceeds 10.0% by mass, the ink aging tends to be unstable. In consideration of the above, 0.1 to 5.0% by mass is preferable, and more in consideration, 0.3 to 3.0% by mass is preferable.

(Organic amine)
Specific examples of the organic amine include amines having an ethylene oxide such as oxyethylene alkylamine and polyoxyethylene alkylamine, alkylamines such as laurylamine and stearylamine, and distearylamine, dimethyllaurylamine and dimethyl. Examples thereof include aliphatic amines such as dimethylalkylamines such as stearylamine and dimethyloctylamine, and among them, amines having ethylene oxide and dimethylalkylamines are preferable in consideration of stability in ink.

Further, the total amine value of the organic amine is preferably 100 to 300 (mgKOH / g) in consideration of stability with an acidic phosphoric acid ester, a colorant and other components. If it exceeds 300 (mgKOH / g), the reactivity is strong and it easily reacts with the above-mentioned components, so that the ink stability with time tends to be inferior. Further, if the total amine value is less than 100 (mgKOH / g), the stability of the acidic phosphoric acid ester in the ink is likely to be affected, and when an oil-based ballpoint pen is used, metals such as balls and chip bodies are used. Adsorption is likely to be inferior and lubrication performance is difficult to obtain. The range of 150 to 300 (mgKOH / g) is preferable in consideration of stability and lubricity with a more acidic phosphoric acid ester, and 200 to 300 (mgKOH / g) is preferable in consideration of more stability. With the most consideration, 230 to 270 (mgKOH / g) is preferable.
The total amine value indicates the total amount of primary, secondary and tertiary amines, and is expressed by the number of mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize 1 g of the sample.

Specific examples of the organic amine include oxyethylene alkylamine, and specific examples of the polyoxyethylene alkylamine include nymine L-201 (total amine value: 232 to 246, secondary amine) and L-202. (Total amine value: 192 to 212, tertiary amine), L-207 (total amine value: 107 to 119, tertiary amine), S-202 (total amine value: 152 to 166, tertiary amine), S-204 (total amine value: 120 to 134, tertiary amine), S-210 (total amine value: 75 to 85, tertiary amine), DT-203 (total amine value: 227 to 247, 3). Grade amines), DT-208 (total amine value: 146 to 180, tertiary amines) (manufactured by Nippon Oil & Fats Co., Ltd.) and the like. Specific examples of the alkylamine include Fermin 80 (total amine value: 204 to 210, primary amine), Fermin D86 (total amine value: 110 to 119, secondary amine), and Fermin DM2098 (total amine value: 254). ~ 265, tertiary amine), Farmin DM8680 (total amine value: 186 to 197, tertiary amine) (Kao Co., Ltd.), Nissan tertiary amine BB (total amine value: 243-263, tertiary amine), same FB (total amine value: 230 to 250, tertiary amine) (manufactured by Nippon Oil & Fats Co., Ltd.) and the like can be mentioned. These may be used alone or in admixture of two or more.

The content of the organic amine is preferably 0.1 to 10.0% by mass with respect to the total amount of the ink composition in consideration of stability with an acidic phosphoric acid ester, a colorant and other components, and will be described later. Considering the neutralization with respect to the surfactant, 0.5 to 5.0% by mass is preferable.

When the content of the acidic phosphoric acid ester with respect to the total amount of the ink composition is A and the content of the organic amine with respect to the total amount of the ink composition is B, 0. The relationship of 1 ≦ A / B ≦ 5 is preferable, and 0.1 ≦ A / B ≦ 3 is preferable if more consideration is given. Further, it is preferable that the relationship is 1 ≦ A / B ≦ 2.

(Colorant)
The colorant used in the present invention is not particularly limited to dyes, pigments and the like, and can be appropriately selected and used, and dyes and pigments may be used in combination. Dyes include oil-soluble dyes, acidic dyes, basic dyes, gold-containing dyes, and various salt-forming type dyes such as salt-forming dyes of acidic dyes and basic dyes, basic dyes and organic acids. Types such as salt-forming dyes with and salt-forming dyes with acidic dyes and organic amines can be mentioned. These dyes may be used alone or in combination of two or more. Specifically, regarding the dyes, Bali First Black 1802, Bali First Black 1805, Bali First Black 1807, Bali First Violet 1701, Bali First Violet 1704, Bali First Violet 1705, Bali First Blue 1601, Bali First Blue 1605, Bali First Blue 1613, Bali First Blue 1621, Bali First Blue 1631, Bali First Red 1320, Bali First Red 1355, Bali First Red 1360, Bali First Yellow 1101, Bali First Yellow 1151, Nigrosin Base EXBP, Nigrosin Base EX, BASE OF BASIC DYES ROB-B, BASE OF BASIC DYES RO6GB, BASE OF BASIC DYES VPB-B, BASE OF BASIC DYES VB-B, BASE OF BASIC DYES MVB-3 (all manufactured by Orient Chemical Industry Co., Ltd.), Eisenspiron Black GMH-Special, Eisenspiron Violet C-RH, Eisenspiron Blue GNH, Eisenspiron Blue 2BNH, Eisenspiron Blue C-RH, Eisenspiron Red C-GH, Eisenspiron Red C-BH, Eisenspiron Yellow C-GNH, Eisenspiron Yellow C-2GH, S.A. P. T. Blue 111, S.A. P. T. Blue GLSH-Special, S.M. P. T. Red 533, S.M. P. T. Orange 6, S.M. B. N. Violet 510, S.A. B. N. Yellow 530, S.A. R. C-BH (above, manufactured by Hodogaya Chemical Co., Ltd.) and the like can be mentioned.

Further, as the colorant, it is preferable to use at least a salt-forming dye in consideration of the stability over time due to compatibility with the acidic phosphate ester which is an acidic substance, and further, the stable salt-forming bond makes it stable over time. Considering that the property can be maintained, it is preferable to use a salt-forming dye of a basic dye and an organic acid, a salt-forming dye of a basic dye of an acidic dye, and a salt-forming dye of an acidic dye and an organic amine. Considering more, it should be used from among azo-based basic dyes, salt-forming dyes having azo-based skeleton dyes using azo-based acidic dyes, triallylmethane-based basic dyes, and salt-forming dyes having aromatic amines. Of these, the salt-forming dye of an azo-based acidic dye and a basic dye, and the salt-forming dye of an azomethine-based basic dye and an organic acid are less likely to affect the acidic phosphoric acid ester because the bond is stable. , It is preferable to use from among salt-forming dyes of acidic dyes and aromatic amines.
Further, regarding the organic acid constituting the salt-forming dye, if it is an organic acid having a phenylsulfonic acid group, it is easy to form a lubricating film that easily adsorbs to the metal, the lubricity is improved, and the writing quality and the wear of the ball seat are suppressed. , And specific examples thereof include alkylbenzene sulfonic acid, naphthalene sulfonic acid, naphthalene sulfonic acid-formaldehyde condensate, alkyldiphenyl ether disulfonic acid, and polyoxyethylene alkylphenyl ether phosphoric acid. Further, it is preferable to use alkylbenzene sulfonic acid as the organic acid in consideration of long-term stability in the ink even if it is neutralized with a more azo-based basic dye.

Examples of pigments include inorganic, organic, and processed pigments. Specific examples thereof include carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, and diketo. Examples thereof include pyrrolopyrrole-based, quinophthalone-based, slene-based, triphenylmethane-based, perinone-based, perylene-based, dioxazine-based, metallic pigments, pearl pigments, fluorescent pigments, phosphorescent pigments and the like.

As the colorant, it is preferable to use a pigment in consideration of lubricity. This is because the pigment particles are used, and the pigment particles enter the gap between the ball and the chip body, so that the pigment particles act like a bearing. It is easy to use a pigment because it is easy to suppress metal contact, thereby improving lubricity, improving writing quality, and easily obtaining the effect of suppressing wear of the ball seat. In particular, due to the synergistic effect of the lubricating layer made of acidic phosphoric acid ester and the action of pigment particles and bearings, it is easy to maintain lubricity even under high writing pressure (writing load 300-500 gf), suppressing wear of the ball seat and improving writing quality. It can be improved. Further, the average particle size is preferably 1 to 500 nm in consideration of the gap relationship inside the ballpoint pen tip. It is more preferably 30 to 350 nm, and even more preferably 50 to 300 nm. Here, the average particle size is determined by using a laser diffraction method, specifically, a laser diffraction type particle size distribution measuring device (trade name “Microtrac HRA9320-X100”, Nikkiso Co., Ltd.), and using a standard sample or another measuring method. It can be obtained from the particle size (D50) when the cumulative volume of the particle size distribution measured based on the calibrated value is 50%.
Since the pigment exerts the above-mentioned action and effect in the dispersed state of the pigment in the ink composition for an oil-based ballpoint pen, it is preferable to determine the particle size in the dispersed state. Further, the pigment is preferable because it has excellent water resistance and light resistance and good color development can be obtained.

As the type of pigment, considering the lubricity due to the compatibility with the acidic phosphoric acid ester, it is preferable to use it from carbon black, quinacridone-based, slene-based, and diketopyrrolopyrrole-based pigments, and further compatibility with time. Therefore, considering the stability of the ink over time, it is preferable to use a quinacridone-based pigment.

The content of the colorant is preferably 5.0 to 30.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 5.0% by mass, it tends to be difficult to obtain a dark handwriting, and if it exceeds 30.0% by mass, it tends to affect the solubility in the ink. In consideration, 7.0 to 25.0% by mass is preferable, and further consideration is 10.0 to 20.0% by mass.

(Organic solvent)
Examples of the organic solvent used in the present invention include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol monophenyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and diethylene glycol dimethyl ether, 3. -Glycol ether solvents such as methoxybutanol and 3-methoxy-3-methylbutanol, glycol solvents such as diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, butylene glycol and ethylene glycol, benzyl alcohol, methanol and ethanol. , 1-propanol, 2-propanol, isopropanol, isobutanol, t-butanol, propanol alcohol, allyl alcohol, 3-methyl-1-butin-3-ol, ethylene glycol monomethyl ether acetate and other higher alcohols. Examples thereof include organic solvents generally used as inks for writing tools, such as alcohol solvents.

Among these organic solvents, considering the solubility with acidic phosphoric acid ester, the effect of improving the lubricity is also improved by dissolving and stabilizing the oil-based ball pen ink composition using a water-insoluble organic solvent. It is preferable because it is easy to obtain.
Among them, it is preferable to use a glycol ether solvent. This is because the acidity of the acid phosphate ester with the alkoxyethyl group (Cl H _{2l + 1} OCH ₂ CH ₂ O) and the alkoxyl group ( _Cm H _{2m + 1} O) tends to be good and the solubility is stable. Ink aging is easy to stabilize even during long-term storage. Furthermore, when a glycol ether solvent is used, it easily absorbs moisture, so that the strength of the film formed when the tip of the chip dries is softened and the writing performance is easily improved. Considering the effectiveness and stability in the ink, it is preferable to use an aromatic glycol ether solvent. Further, as an organic solvent other than the glycol ether solvent, it is preferable to use an alcohol solvent, which means that the alcohol solvent volatilizes and easily dries at the tip of the tip, and the inside of the writing tip (inside the tip of the tip). This is preferable because it suppresses ink leakage from the gap at the tip of the writing and improves the ink leakage suppressing performance by thickening the viscosity more quickly. Further, aromatic alcohols such as benzyl alcohol also have an effect of improving lubricity, and therefore it is preferable to use at least. Therefore, it is preferable to use a glycol ether solvent and an alcohol solvent in combination.

The content of the organic solvent is preferably 10.0 to 70.0% by mass with respect to the total amount of the ink composition in consideration of improving solubility, handwriting drying property, bleeding and the like. The content of the alcohol solvent is preferably 30.0 to 90.0% by mass, more preferably 50.0 to 90.0, based on the total organic solvent, in consideration of the drying property at the tip of the chip. It is mass%.

(resin)
Further, in order to further improve the suppression of ink leakage, it is preferable to use a resin as an ink viscosity adjusting agent. As the resin, polyvinyl butyral resin, ketone resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, terpene resin, etc. Examples thereof include alkyd resin, phenoxy resin, polyvinyl acetate resin and the like, and among them, polyvinyl butyral resin or ketone resin is preferably contained.

For ketone resin, when used in combination with acidic phosphoric acid ester, the lubricating action is easy to work synergistically, and under high writing pressure (writing load 300 to 500 gf), lubricity is improved and wear suppression of the ball seat is further improved. It is preferable to do so. Among the ketone resins, a ketone resin having a cyclic structure such as an aromatic ring skeleton (having a benzene ring such as a phenyl group, an acetophenone group, or a naphthalene group) or a cyclohexane skeleton (having a cyclohexane ring such as a cyclohexane group or a cyclohexanone group) can be used. preferable. This is because the cushioning effect of the ketone resin having an annular structure can be obtained, the lubricity is improved under high writing pressure (writing load 300 to 500 gf), and the wear suppression of the ball seat is further improved, and more preferably. A ketone resin having an aromatic ring has a large number of double-bonded structures, so that a stronger cushioning effect can be easily obtained. Therefore, lubricity under high writing pressure (writing load 300 to 500 gf) is effective and preferable. ..

When the polyvinyl butyral resin is also used in combination with an acidic phosphoric acid ester, it is easy to form a lubricating layer capable of obtaining a higher lubricating effect. Therefore, an elastic ink layer is always formed between the ball and the ball seat to make it difficult to make direct contact with the ball, which makes it easy to improve the writing quality. Further, it is preferable to use the polyvinyl butyral resin because the film formed makes it easier to improve ink leakage, and when a pigment is used as a colorant, a pigment dispersion effect can be obtained. Therefore, the polyvinyl butyral resin is used. It is preferable to use it.
Here, the polyvinyl butyral resin is obtained by reacting polyvinyl alcohol (PVA) with butyraldehyde (BA), and has a structure having a butyral group, an acetyl group, and a hydroxyl group.

The polyvinyl butyral resin preferably has a hydroxyl group content of 25 mol% or more. This is because polyvinyl butyral resin with a hydroxyl group content of less than 25 mol does not have sufficient solubility in an organic solvent, and it is difficult to obtain a sufficient lubricating effect and an effect of suppressing ink leakage. Further, considering the writing performance due to moisture absorption. This is because it is preferable to use a polyvinyl butyral resin having a hydroxyl group content of 25 mol% or more. Further, the polyvinyl butyral resin having a hydroxyl group content of 30 mol% or more is preferable because the writing quality is easily improved. This is because at the time of writing, frictional heat is generated by the rotation of the ball, which warms the ink at the tip of the chip and raises the temperature of the ink, but the polyvinyl butyral resin is different from other resins. Even if the ink temperature rises, it has the property of making it difficult to lower the ink viscosity, and it always forms an elastic ink layer between the ball and the ball seat, making it difficult to make direct contact, improving the writing quality. It tends to be easy. In particular, a ballpoint pen is effective for writing tools because it often writes with high writing pressure. Further, when a polyvinyl butyral resin having a hydroxyl group content of more than 40 mol% is used, the amount of moisture absorption tends to increase and the stability with time with the ink component tends to be affected. Therefore, a polyvinyl butyral resin having a hydroxyl group content of 40 mol% or less is preferable. Therefore, a polyvinyl butyral resin having a hydroxyl group content of 30 to 40 mol% is preferable, and a hydroxyl group content of 30 to 36 mol% is more preferable.
The amount of hydroxyl groups (mol%) of the polyvinyl butyral resin includes hydroxyl groups (mol%) with respect to the total mol amount of butyral groups (mol%), acetyl groups (mol%), and hydroxyl groups (mol%). It shows the rate.

Regarding the average degree of polymerization of polyvinyl butyral resin, when the average degree of polymerization is 200 or more, the ink leakage suppressing performance is likely to be improved, and when the average degree of polymerization exceeds 2500, the ink viscosity becomes too high. The average degree of polymerization is preferably 200 to 2500 because it tends to affect the writing quality. Further, more considered, the average degree of polymerization is preferably 1500 or less, and more preferably 1000 or less. Here, the average degree of polymerization refers to the number of basic units constituting one molecule of polyvinyl butyral resin, and a value measured based on the method specified in JIS K6728 (2001 version) can be adopted. ..

The content of the polyvinyl butyral resin is 70% or more with respect to the content of the total resin in the oil-based ballpoint pen composition, and it is preferable to use it as the main resin. This is because when the content of the polyvinyl butyral resin is less than 70% of the content of the total resin, it is easy for other resins to hinder the formation of an elastic ink layer, which has the effect of improving the writing quality. It becomes difficult to obtain, and it is easy to inhibit the formation of the resin film at the tip of the chip, the ink dripping cannot be suppressed, and the formation of an elastic ink layer is inhibited, so that the effect of improving the writing quality is obtained. This is because it becomes difficult to get rid of. Considering the tendency to improve the writing quality and the ink dripping performance, the content of the polyvinyl butyral resin is preferably 90% or more with respect to the content of the total resin.

If the content of the polyvinyl butyral resin is less than 1.0% by mass with respect to the total amount of the ink composition, the desired lubricity and ink leakage suppressing performance are likely to be inferior, and if it exceeds 40.0% by mass, the ink is contained. Since the solubility tends to be inferior, 1.0 to 40.0% by mass is preferable with respect to the total amount of the ink composition. Further, considering it, 5.0% by mass or more is preferable, and if it exceeds 30.0% by mass, the ink viscosity tends to be too high and the writing quality tends to be affected, so 5.0 to 30.0% by mass is preferable. preferable.

Specifically, the polyvinyl butyral resin is a trade name manufactured by Sekisui Chemical Industry Co., Ltd .; Eslek BH-3 (hydroxyl amount: 34 mol%, average degree of polymerization: 1700), BH-6 (hydroxyl amount: 30 mol%). , Average degree of polymerization: 1300), BX-1 (hydroxyl amount: 33 ± 3 mol%, average degree of polymerization: 1700), BX-5 (hydroxyl amount: 33 ± 3 mol%, average degree of polymerization: 2400), BM -1 (Amount of hydroxyl group: 34 mol%, average degree of polymerization: 650), BM-2 (amount of hydroxyl group: 31 mol%, average degree of polymerization: 800), BM-5 (amount of hydroxyl group: 34 mol%, average degree of polymerization: 850) ), BL-1 (Amount of hydroxyl group: 36 mol%, average degree of polymerization: 300), BL-1H (Amount of hydroxyl group: 30 mol%), BL-2 (Amount of hydroxyl group: 36 mol%, average degree of polymerization: 450), BL-2H (hydroxyl amount: 29 mol%), BL-10 (hydroxyl amount: 28 mol%), etc., and trade name manufactured by Kuraray Co., Ltd .; Mobital B20H (hydroxyl amount: 26 to 31 mol%, average degree of polymerization: 250-500), B30T (amount of hydroxyl group: 33-38 mol%, average degree of polymerization: 400-650), B30H (amount of hydroxyl group: 26-31 mol%, average degree of polymerization: 400-650), B30HH (amount of hydroxyl group) : 30-34 mol%, average degree of polymerization: 400-650), B45H (hydroxyl amount: 26-31 mol%, average degree of polymerization: 600-850), B60T (hydroxyl amount: 34-38 mol%, average degree of polymerization: 750 to 1000), B60H (amount of hydroxyl group: 26 to 31 mol%, average degree of polymerization: 750 to 1000), B75H (amount of hydroxyl group: 26 to 31 mol%, average degree of polymerization: 1500 to 1750) and the like. These may be used alone or in admixture of two or more.

As the resin other than the polyvinyl butyral resin and the ketone resin, a spinnability-imparting agent may be appropriately used. In particular, it is preferable to contain polyvinylpyrrolidone resin because it is easy to improve the binding property of the ink and suppress the generation of excess ink at the tip of the chip by blending the polyvinylpyrrolidone resin. If the content of the polyvinylpyrrolidone resin is less than 0.01% by mass with respect to the total amount of the ink composition, it tends to be difficult to suppress the generation of excess ink. Therefore, if it exceeds 3.0% by mass, it is contained in the ink. Since the solubility tends to be inferior, 0.01 to 3.0% by mass is preferable with respect to the total amount of the ink composition. Considering the above reasons, 0.1 to 2.0% by mass is preferable. Specific examples thereof include trade names manufactured by ASP Japan Co., Ltd .; PVP K-15, PVP K-30, PVP K-90, PVP K-120 and the like. These may be used alone or in admixture of two or more.

(Surfactant)
In the present invention, it is preferable to use a surfactant in consideration of the above-mentioned lubricity and the improvement of the writing performance when the tip tip is dried while the tip tip is left in the atmosphere. .. This is because when a surfactant is used, the formed film tends to be softened, the writing performance can be improved, and the lubricity can also be improved. Examples of the surfactant include fatty acids, fatty acid esters, silicone-based surfactants, fluorine-based surfactants, and phosphate ester-based surfactants (excluding the acidic phosphate esters of the general formulas (Chemical formula 1) and (Chemical formula 2)). And so on. Among them, considering the above effects, one of fatty acids, silicone-based surfactants, and phosphate ester-based surfactants (excluding the acidic phosphate esters of the general formulas (Chemical formula 1) and (Chemical formula 2)). It is preferable to use the above.
In particular, with respect to the acidic phosphoric acid ester used in the present invention, the phosphoric acid ester-based surfactant (excluding the acidic phosphoric acid esters of the general formulas (Chemical formula 1) and (Chemical formula 2)) has phosphoric acid as the same skeleton. It is preferable to use a phosphate ester-based surfactant (excluding the acidic phosphate esters of the general formulas (Chemical formula 1) and (Chemical formula 2)) because they are compatible with each other and a synergistic lubricating effect can be easily obtained. This can be done by using an acidic phosphoric acid ester and a phosphoric acid ester-based surfactant (excluding the acidic phosphoric acid esters of the general formulas (Chemical formula 1) and (Chemical formula 2)) in combination with the lubricating layer of the acidic phosphoric acid ester. By interacting with the lubricating layer with the phosphoric acid ester-based surfactant, a lubricating layer with higher lubricity can be formed, so that the lubricity is maintained even under high writing pressure (writing load 300 to 500 gf), and the ball It is presumed that it has the effect of making it easier to suppress the wear of the seat. Further, when the above-mentioned polyvinyl butyral resin is used, it is more preferable because the ink layer and the lubricating layer formed by the polyvinyl butyral make it easier to improve the lubricity.

The HLB value of the surfactant is preferably 6 to 14 in consideration of further improving both the writing performance and the lubricity. This is because when the HLB value exceeds 14, the hydrophilicity tends to be strong, and the solubility in the oil-based ink tends to be inferior, so that the effect of the surfactant is difficult to obtain and the lubricating effect is difficult to obtain. .. Further, when the HLB value is less than 6, the lipophilicity becomes too strong, the compatibility with the organic solvent is likely to be affected, the ink aging is difficult to stabilize, and the writing performance is difficult to improve. Further, considering the lubricity, the HLB value is preferably 12 or less, the HLB value is preferably 6 to 12, and further considering the writing performance, the HLB value is preferably 7 to 12.
The HLB can be obtained from the Griffin method, the upstream method, etc., and as an example, as a general formula, HLB = 7 + 11.7 log (Mw / Mo), (Mw; molecular weight of hydrophilic group, Mo; lipophilic group). It can be obtained from the molecular weight) and the like. In particular, in haunting writing instruments such as knock-type writing instruments and rotary feeding-type writing instruments, unlike cap-type writing instruments, the pen tip is always exposed to the outside, which affects the writing performance when the writing tip is dried. Since it is easy, it is more preferable to use the surfactant having the above HLB value.

Specific examples of the surfactant include oleic acid, stearic acid, and linoleic acid as fatty acids, and dimethyl silicone, methylphenyl silicone, polyether-modified silicone, and higher grade silicone-based surfactants. Examples of the fluorine-based surfactant include fatty acid ester-modified silicones, and examples thereof include perfluoro group butyl sulfonate, perfluoro group-containing carboxylate, perfluoro group-containing phosphoric acid ester, and perfluoro group-containing phosphoric acid ester type compound. Examples include substances, perfluoroalkyl betaines, perfluoroalkylamine oxide compounds, and the like, and examples of the phosphate ester-based surfactant (excluding the acidic phosphate esters of the general formulas (Chemical formula 1) and (Chemical formula 2)) are polyoxy. Phosphoric acid monoester of ethylene alkyl ether or polyoxyethylene alkylaryl ether, phosphoric acid diester of polyoxyethylene alkyl ether or polyoxyethylene alkylaryl ether, phosphoric acid triester of polyoxyethylene alkyl ether or polyoxyethylene alkylaryl ether , Alkyl phosphate ester, alkyl ether phosphoric acid ester or derivatives thereof and the like. When a phosphate ester-based surfactant (excluding the acidic phosphate esters of the general formulas (Chemical formula 1) and (Chemical formula 2)) is used, the acid value is preferably 160 or less, which is phosphorus. In order to facilitate the improvement of lubricity by the acid ester-based surfactant, the acid value is preferably 30 to 160 in consideration of stability in ink and lubricity, and more in consideration, acid. The value is preferably 70 to 160. The acid value is expressed by the number of mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of the sample.

The content of the surfactant is more preferably 0.1 to 5.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, it tends to be difficult to obtain the desired lubricity, and if it exceeds 5.0% by mass, the ink tends to become unstable over time. In consideration of the above, 0.3 to 3.0% by mass is preferable with respect to the total amount of the ink composition, and more preferably, 0.5 to 3.0% by mass is most preferable.

When the content of the acidic phosphoric acid ester with respect to the total amount of the ink composition is X and the content of the surfactant with respect to the total amount of the ink composition is Y, a balance between writing performance and suppression of wear of the ball seat is achieved. If considered, the relationship of 0.1 ≦ X / Y ≦ 7 is preferable, and if more considered, the relationship of 0.1 ≦ X / Y ≦ 5 is preferable.

(Fatty acid ester)
In the present invention, it is preferable to use a fatty acid ester in consideration of the lubricity and the improvement of the writing performance when the tip tip is dried while the tip tip is left in the atmosphere. The fatty acid ester makes it easier to soften the film strength formed during ink drying at the tip of the chip, which makes it easier to improve writing performance, and further makes it easier to improve lubricity, resulting in high writing pressure (writing load 300). It is preferable because it is easy to maintain the lubricity even at ~ 500 gf), and it is easy to suppress the wear of the ball seat (high writing pressure writing property) and to improve the writing quality and the writing performance.

The fatty acid ester is an esterification reaction of a fatty acid with an alcohol such as a monohydric alcohol or a polyhydric alcohol. Among the fatty acid esters, a branched chain is considered in consideration of further improving the writing performance. It is preferable to use a fatty acid ester having an alkyl group. This is because the fatty acid ester having a branched chain alkyl group has a bulkier structure than the linear structure, and therefore, due to the bulkiness of the branched chain alkyl group, it is adsorbed on the metal ball surface or the ball seat of the chip body. This is because it is easy to form a thicker lubricating film and the lubricity is more easily improved. At the same time, the bulkiness of the branched chain alkyl group softens the film strength formed when the tip of the chip is dried with ink, resulting in writing performance. This is to improve.

Further, the fatty acid ester preferably has an acid value of 0.01 to 5 (mgKOH / g), which has good compatibility with the acidic phosphoric acid ester and other components in the oil-based ink. This is because it is stable in the ink for a long period of time, so that it is possible to improve the writing performance for a long period of time, improve the lubricity for a long period of time, and easily improve the writing quality. For further consideration, the acid value is preferably 0.01 to 2.5 (mgKOH / g), more preferably 0.05 to 1.0 (mgKOH / g).
The acid value is expressed by the number of mg of potassium hydroxide required to neutralize the acidic component (free fatty acid) contained in 1 g of the sample.

The alcohol used in the esterification reaction of the fatty acid ester is preferably a polyhydric alcohol. The reason for this is not clear, but the more hydroxyl groups of the alcohol used in the esterification reaction of the fatty acid ester, the easier the moisturizing effect, and the softer the strength of the film formed when the tip of the chip dries. Since the effect of smoothing the rotation of the ball can be obtained, it is presumed that the writing performance is improved without causing brush stroke blurring. Considering that the writing performance is further improved, it is preferable that the polyhydric alcohol has a hydroxyl group having a hydroxyl group of 4 or more, and more preferably the hydroxyl group has a hydroxyl group of 5 or more. Further, if the number of hydroxyl groups is too large, the stability in oil-based ink is likely to be affected, so that the number of hydroxyl groups is preferably 8 or less.

Specific examples of the alcohol used in the esterification reaction of the fatty acid ester include pentanol, cyclohexanol, hexanol, heptanol, octanol, 2-ethylhexanol, nonanol, isononanol, decanol, lauryl alcohol, and mi. Examples thereof include styryl alcohol, stearyl alcohol and docosanol. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, polyalkylene glycol, 1,3-propanediol, diethylene glycol, glycerin, 2-methylpropanetriol, neopentyl glycol, trimethylolethane, trimethylolethane, trimethylolpropane, and penta. Examples thereof include erythritol, dipentaerythritol, and tripentaerythritol. Among these, it is preferable to contain a fatty acid ester esterified with pentaerythritol such as pentaerythritol, dipentaerythritol, and tripentaerythritol in order to further improve the writing performance and consider the stability over time of the ink. For example, it preferably contains a fatty acid ester esterified with dipentaerythritol.

Specific examples of the fatty acid used in the esterification reaction of the fatty acid ester include valeric acid, isovaleric acid, caproic acid, 2-ethylbutanoic acid, heptanic acid, 2-methylhexanoic acid and 3 as monocarboxylic acids. -Methylhexanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, isoheptanoic acid, capric acid, 2-ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid, neononanoic acid, capric acid, neodecanoic acid , Lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, araquinic acid and the like. Specific examples of the polyvalent carboxylic acid include succinic acid, glutanoic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, fumaric acid, maleic acid, trimellitic acid, and pyromellitic acid.

The content of the fatty acid ester is more preferably 0.1 to 10.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, it tends to be difficult to obtain the desired writing performance and lubricity, and if it exceeds 10.0% by mass, the ink aging tends to be unstable. Considering the tendency, 0.1 to 5.0% by mass is preferable, and more considering it, 0.1 to 3.0% by mass is preferable, and 0.3 to 2.0% by mass is most preferable.

The compounding ratio of the acidic phosphate ester to the fatty acid ester (acidic phosphate ester / fatty acid ester) is preferably 0.01 to 5 times on a mass basis. This is because it is easy to achieve both the suppression of wear of the ball seat and the writing performance in the above range. Considering more, it is preferable that the compounding ratio is 0.05 to 3 times based on the mass. Considering the above, it is preferable that the compounding ratio is 0.1 to 2 times based on the mass.

In addition, as a viscosity adjusting agent, a resin such as terpene resin, alkyd resin, phenoxy resin, polyvinyl acetate, a pseudoplasticity-imparting agent such as fatty acid amide, hydrogenated castor oil, a colorant stabilizer, and a plasticizer are used. , Chelating agent, water and the like may be used as appropriate. These may be used alone or in combination of two or more.

The ink viscosity of the ink composition for an oil-based ball pen of the present invention is not particularly limited, but when the ink viscosity at 20 ° C. and a shear rate of 5 sec ^-1 (at rest) exceeds 30,000 mPa · s, writing performance and writing are performed. Since the taste tends to be inferior, the ink viscosity at 20 ° C. and a shear rate of 5 sec ^-1 (at rest) is preferably 30,000 mPa · s or less. Further, if the ink viscosity at 20 ° C. and a shear rate of 5 sec ^-1 (at rest) is less than 3000 mPa · s, it is difficult to suppress ink leakage. Therefore, considering ink leakage, it is preferably 3000 mPa · s or more. The ink viscosity is more preferably 5000 to 25000 mPa · s, and further considered to be 5000 to 20000 mPa · s, in consideration of further improving ink leakage suppression, writing taste, ink follow-up performance, and writing performance. preferable.

In order to maintain the stability and lubricity of the ink with time, such as suppressing metal salt precipitates in the ink composition for oil-based ballpoint pens of the present invention, the pH value is preferably 3.0 to 10.0. This is because if the pH value is less than 3.0, metal ions in the chip body are likely to elute, so that metal salt precipitates are likely to occur. If the pH value exceeds 10.0, the colorant in the ink or This is because the ionic bonds of the surfactant are easily separated, which tends to affect the ink stability over time, the lubricity, and the color tone, and further, the pigment dispersion stability cannot be obtained. Further, the pH value is preferably 3.0 to 9.0 in consideration of the stability with time of the ink, and the pH value is preferably 3.5 to 8.0 in consideration of the stability with time.

In the method for measuring the ink composition for an oil-based ballpoint pen, the pH value in the present invention is obtained by collecting oil-based ink in a container, adding ion-exchanged water, heating while stirring, heating, and then allowing to cool. After replenishing the amount of evaporated water, it is filtered using a filter paper. Using the upper layer of the filtered filtrate, the pH measurement shows the value measured at 20 ° C. using an IM-40S type pH meter manufactured by DKK-TOA CORPORATION.

The arithmetic average roughness (Ra) of the ball surface of the ballpoint pen tip used in the present invention is preferably 0.1 to 12 nm. This is because if the arithmetic average roughness (Ra) is less than 0.1 nm, it is difficult for the ink to be sufficiently applied to the ball surface, it is difficult to obtain a dark handwriting when writing, and the handwriting is prone to line skipping and blurring. When the roughness (Ra) exceeds 12 nm, the surface of the ball is too rough and the rotation resistance between the ball and the ball seat is large, so that the writing quality tends to be inferior. This is because it is easy to affect. Further, when the arithmetic mean roughness (Ra) is 0.1 to 10 nm, it is more preferable and more preferably 2 to 10 nm because the ink is easily placed on the ball surface when an acidic phosphoric acid ester or polyvinyl butyral resin is used. It is 8 nm. The surface roughness can be measured by (model name SPI3800N manufactured by Seiko Epson Corporation).

The material used for the balls is not particularly limited, but is limited to cemented carbide balls containing tungsten carbide as a main component, metal balls such as stainless steel, and ceramics such as silicon carbide, silicon nitride, alumina, silica, and zirconia. Examples include balls and ruby balls.
Further, if the diameter of the ball is a relatively small ball diameter of 0.7 mm or less, the smaller the diameter of the ball, the higher the number of rotations of the ball when writing at the same distance. Since the wear of the ball tends to be severe, it is effective to use the acidic phosphate ester used in the present invention, and further, when the ball diameter is 0.5 mm or less, the writing pressure is high (writing load 300 to 500 gf). , It is more effective because the ball seat is easily worn.

The material of the ball pen tip includes metal materials such as stainless steel, nickel silver, brass (brass), aluminum bronze, and aluminum, and resin materials such as polycarbonate, polyacetal, and ABS. Considering the property, it is preferable to use a stainless steel chip body.

Further, it is preferable that the amount of movement of the ball of the ballpoint pen tip used in the present invention in the vertical axis direction is 3 to 20 μm. This is because if it is less than 3 μm, it becomes difficult to obtain a dark handwriting and a good writing taste, and if it exceeds 20 μm, the ink dripping performance is likely to be affected. Is preferable.

Next, the present invention will be described with reference to examples.
In the ink composition for an oil-based ball pen of Example 1, a pigment and a pigment dispersant were added to an organic solvent and dispersed by a disperser, and then a pigment dispersion, a dye, an organic solvent, a ketone resin, an acidic phosphoric acid ester, and a spinning thread were prepared. Polyvinylpyrrolidone was adopted as the sex-imparting resin, weighed it in a predetermined amount, heated to 60 ° C., and then completely dissolved using a disperser stirrer to obtain an ink composition for an oil-based ball pen. The specific blending amount is as follows.
The ink viscosity of Example 1 was measured at a shear rate of 5 sec ^-1 (rotation speed 2.5 rpm) in an environment of 20 ° C. using a viscometer Viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield Co., Ltd. The ink viscosity was 10000 mPa · s.

Example 1
Colorant (salt-forming dye of azo acid dye and basic dye) 10.0% by mass
Colorant (salt-forming dye of azomethine-based basic dye and organic acid) 5.0% by mass
Pigment dispersion (pigment content 12%, quinacridone pigment) 10.0% by mass
Acidic phosphate ester (mixture of n = 1 and n = 2 with conversion 1: l = 4) 1.0% by mass
Alcohol solvent (benzyl alcohol) 9.5% by mass
Glycol ether solvent (ethylene glycol monophenyl ether) 40.0% by mass
Surfactant 2.0% by mass
Organic amine (secondary amine) 2.0% by mass
Ketone resin (ketone resin with aromatic ring) 20.0% by mass
Spinning property imparting resin (polyvinylpyrrolidone resin) 0.5% by mass

Examples 2 to 24
As shown in the table, inks were blended in the same procedure as in Example 1 except that the components and chip specifications were changed to obtain ink compositions for oil-based ballpoint pens of Examples 2 to 24. The table shows the measurement and evaluation results.

Comparative Examples 1 to 4
As shown in the table, the ink compositions for oil-based ballpoint pens of Comparative Examples 1 to 4 were obtained in the same procedure as in Example 1 except that the components and chip specifications were changed. The table shows the measurement and evaluation results.

Test and Evaluation A ballpoint pen in which a ball (φ0.5 mm) is rotatably held at the tip of an ink storage cylinder (made of polypropylene) of the oil-based ballpoint pen ink compositions prepared in Examples 1 to 24 and Comparative Examples 1 to 4. A ballpoint pen refill Co., Ltd. is used by mounting a chip (movement amount in the vertical axis direction of the ball: 6 μm) and directly storing the oil-based ballpoint pen ink (0.2 g) of Example 1 in the ink storage cylinder. An oil-based ballpoint pen manufactured by Corporation (trade name: Super Grip (registered trademark)) was placed to prepare an oil-based ballpoint pen, and the following tests and evaluations were performed using the writing paper JIS P3201 as the writing test paper.

High writing pressure wear resistance test (wear test of ball seat): Wear of the ball seat after the writing test was measured with a running tester having a load of 300 gf and a writing angle of 70 ° and 4 m / min.
Ball seat wear less than 5 μm ・ ・ ・ ◎
The wear of the ball seat is 10 μm or more and less than 20 μm, but it is possible to write ... △
The ball seat is badly worn, resulting in poor writing ... ×

Writing taste: A handwritten sensory test was performed and evaluated.
Very smooth ... ◎
Smooth ... ○
Smoothness that is not a problem in practice ... △
Heavy things ... ×

Ink time test: The ink inside the chip body was observed under a microscope.
Good with no deposits ... ◎
A small amount of precipitates ... ○
Precipitates were generated, but there is no problem in practical use ... △
Precipitates that cause blurring and poor writing ... ×

Writing performance test: After writing by handwriting, leave it in an environment of 20 or 65% RH for 30 minutes with the tip of the chip exposed, and then write in the running test under the following writing conditions, and the length of handwriting blur in writing. Was measured.
<Writing conditions> Under the conditions of a writing load of 70 gf, a writing angle of 70 °, and a writing speed of 4 m / min, straight-line writing was performed with a running tester and evaluated.
Handwriting cassoulet length is less than 10 mm ... ◎
The length of the handwriting blur is 10 mm or more and less than 20 mm ... ○
The length of the handwriting blur is 20 mm or more and less than 40 mm ... △
Handwriting Cassoulet with a length of 40 mm or more ... ×

In Examples 1 to 24, good performance was obtained in all of the high writing pressure wear resistance test (ball seat wear test), writing quality, ink aging test, and writing performance test.
In Examples 21 to 24, fatty acid esters were contained in Examples 1, 3, 16 and 20, but when the writing performance was compared, Examples 21 to 24 showed particularly good results.

In Comparative Examples 1 to 4, since the acidic phosphoric acid ester was not used, in the high writing pressure wear resistance test (wear test of the ball seat), the ball seat was severely worn and the handwriting was scratched, resulting in poor writing. there were. Further, in Comparative Examples 1 and 2, the writing quality and writing performance were also inferior.

Further, when a haunting type oil-based ball pen such as a knock-type oil-based ball pen or a rotary feeding type oil-based ball pen is used, the writing performance is one of the important performances. It is effective to use an ester-based surfactant (excluding the acidic phosphate esters of the general formulas (Chemical formula 1) and (Chemical formula 2)) in combination.

Further, in the present embodiment, an oil-based ballpoint pen in which a ballpoint pen refill containing an ink composition for an oil-based ballpoint pen is arranged in a shaft cylinder is exemplified, but in the oil-based ballpoint pen of the present invention, the shaft cylinder itself is inked. The storage cylinder may be a direct-packed oil-based ballpoint pen in which the ink composition for an oil-based ballpoint pen is directly stored in the shaft cylinder, or the ink composition for an oil-based ballpoint pen is stored in the ink storage cylinder (ballpoint pen refill). ) May be used as it is as a ballpoint pen.

The present invention can be used as an ink composition for an oil-based ballpoint pen, and more specifically, can be widely used as a cap-type, knock-type or the like oil-based ballpoint pen filled with the ink composition for an oil-based ballpoint pen.

Claims (7)

An oil-based ball pen having a ball pen tip rotatably holding a ball at the tip of the ink storage cylinder and accommodating an ink composition for an oil-based ball pen in the ink storage cylinder, and for the oil-based ball pen. The ink composition is a pigment, an organic solvent, an acidic phosphate ester of the general formula (Chemical formula 1) or (Chemical formula 2), and a phosphate ester-based surfactant having an HLB value of 6 to 14 (general formula (Chemical formula 1), (Excluding the acidic phosphoric acid ester of Chemical formula 2)) Containing an organic amine which is a secondary amine or a tertiary amine, the content of the acidic phosphoric acid ester with respect to the total amount of the ink composition is X, and the HLB value is 6. When the content of the phosphoric acid ester-based surfactants (excluding the acidic phosphoric acid esters of the general formulas (Chemical formula 1) and (Chemical formula 2)) with respect to the total amount of the ink composition is Y, 0.1 ≤ X. An oil-based ball pen having a relationship of / Y≤5 and characterized in that the amount of movement of the ball of the ball pen tip in the vertical axis direction is 3 to 20 μm.

The oil-based ballpoint pen according to claim 1, wherein the acidic phosphoric acid ester is a mixture of a monoester and a diester, and the mixing ratio is 1: 1 to 1: 5. The oil-based ballpoint pen according to claim 1 or 2, wherein the content of the acidic phosphoric acid ester is 0.1 to 10.0% by mass with respect to the total amount of the ink composition. The oil-based ball pen ink composition contains a fatty acid ester, and the compounding ratio of the acidic phosphate ester to the fatty acid ester (acidic phosphate ester / fatty acid ester) is 0.01 to 5 times on a mass basis. The oil-based ball pen according to any one of claims 1 to 3, wherein the oil-based ball pen is characterized by the above. The oil-based ballpoint pen according to any one of claims 1 to 4, wherein the ink composition for an oil-based ballpoint pen further contains a salt-forming dye. The oil-based ballpoint pen according to any one of claims 1 to 5, wherein the ink viscosity at 20 ° C. and a shear rate of 5 sec ^-1 is 30,000 mPa · s or less. The oil-based ballpoint pen according to any one of claims 1 to 6 , wherein the ball diameter is 0.5 mm or less.