Oil-based ballpoint pen

Abstract

To provide an oil-based ballpoint pen with a firm writing feel (comfort) and high ink consumption to produce a thick handwriting.SOLUTION: The oil-based ballpoint pen has a ballpoint pen tip at the tip of an ink storage cylinder, and the ink storage cylinder contains an ink composition for oil-based ballpoint pens containing a colorant, an organic solvent, and resin. The ink viscosity of the ink composition for the oil-based ballpoint pen is 1000 mPa s or more and 10,000 mPa s or less at a shear rate of 200 sec-1 at 20°C. The coefficient of friction of the oil-based ballpoint pen is 0.13 or higher at a writing speed of 4 m / min under a writing load of 200 gf and a writing angle of 70°. The ink consumption of the oil-based ballpoint pen is 30 mg or more and 100 mg or less per 100 m.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an oil-based ballpoint pen. [Background technology]

[0002] Conventional oil-based ballpoint pen inks have a high ink viscosity, which results in a heavy writing feel, little ink discharge, and thin handwriting. Furthermore, the writing resistance is high, which results in poor lubrication and accelerates wear on the ball seat, resulting in poor writing. (Patent Document 1)

[0003] To solve these problems, oil-based ballpoint pen inks are low-viscosity inks of 10,000 mPa·s or less, making them smoother, improving the writing feel, and providing good writing performance (Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Application No. 6-64988 [Patent Document 2] JP 2004-107594 A [Patent Document 3] JP 2001-152069 A Summary of the Invention [Problem to be solved by the invention]

[0005] By setting the oil-based ballpoint pen ink to a low viscosity ink or using a variety of lubricants, it has become possible to reduce the writing resistance between the writing tip and the surface being written on, improving the writing feel and also improving the ink ejection to produce thick handwriting. However, there is still room for improvement, as the ball slides too much, resulting in writing mistakes, a lack of a writing feel, and an uneasy writing experience.

[0006] An object of the present invention is to provide an oil-based ballpoint pen which has a good writing feel (comfort) while consuming a large amount of ink and producing thick handwriting. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention "1. An oil-based ballpoint pen having a ballpoint tip at the tip of an ink reservoir, and containing an ink composition for an oil-based ballpoint pen, the ink reservoir containing the ballpoint tip containing a colorant, an organic solvent, and a resin, The ink viscosity of the ink composition for oil-based ballpoint pens is 20° C. at a shear rate of 200 sec -1 In the above, the viscosity is 1000 mPa s or more and 10000 mPa s or less, The oil-based ballpoint pen has a friction coefficient of 0.13 or more at a writing speed of 4 m / min under a writing load of 200 gf and a writing angle of 70°; An oil-based ballpoint pen characterized by an ink consumption of 30 mg or more and 100 mg or less per 100 m. 2. The oil-based ballpoint pen according to claim 1, characterized in that the ratio of the friction coefficient X at a writing speed of 4 m / min under a writing load of 200 gf and a writing angle of 70° to the friction coefficient Y at a writing speed of 0.1 m / min under a writing load of 200 gf and a writing angle of 70° is 0.8≦X / Y≦1.3. 3. The oil-based ballpoint pen according to claim 1 or 2, wherein the resin is selected from the group consisting of rosin resin, ketone resin, and terpene phenol resin. 4. The oil-based ballpoint pen described in item 1 or 2, characterized in that the softening point of the resin is 50°C or higher and 130°C or lower. 5. The oil-based ballpoint pen described in item 1 or 2, characterized in that the resin content is 10% by mass or more and 40% by mass or less. 6. The oil-based ballpoint pen according to item 1 or 2, wherein the surfactant is a phosphate ester surfactant or a fatty acid. Effect of the Invention

[0008] To provide an oil-based ballpoint pen that has a good writing feel (feel) without the ball being too slippery, has good ink ejection, can increase ink consumption, and can produce thick handwriting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In this specification, the units "parts", "%", "ratio" and the like indicating the composition are based on mass unless otherwise specified.

[0010] The present invention is characterized in that the ink reservoir has a ballpoint tip at the tip of the ink reservoir, and the ink reservoir contains an ink composition for an oil-based ballpoint pen, which contains a colorant, an organic solvent, and a resin. The ink composition for an oil-based ballpoint pen has an ink viscosity of 200 s at a shear rate of 200 s under an environment of 20° C. -1 For oil-based ballpoint pens, the friction coefficient is 0.13 or more at a writing speed of 4 m / min under a writing load of 200 gf and a writing angle of 70°, and the ink consumption per 100 m is 30 mg or more and 100 mg or less, thereby making it possible to increase the ink consumption and produce thick handwriting while maintaining a firm writing feel (comfort).

[0011] (friction coefficient) For the oil-based ballpoint pen used in the present invention, by setting the friction coefficient at a writing speed of 4 m / min at a writing load of 200 gf and a writing angle of 70° to 0.13 or more, it is possible to obtain a firm writing feel (comfort) with a weighted writing feel without the ball slipping too much. Furthermore, to obtain a firmer writing feel (comfort), the friction coefficient is preferably 0.14 or more, more preferably 0.15 or more, and even more preferably 0.16 or more. On the other hand, if the friction coefficient of an oil-based ballpoint pen is too large, the writing feel will be too heavy, the writing feel will be poor, the ink ejection properties will be poor, it will be difficult to obtain thick handwriting, and the ball seat will be more susceptible to wear, so the friction coefficient is preferably 0.20 or less, and more preferably 0.19 or less. The friction coefficient relationship is calculated using the following formula. Friction coefficient (dynamic friction coefficient) = writing resistance (dynamic friction force) / writing load (normal force) <Written resistance measurement> The ballpoint pen refill obtained above was loaded into an exterior case, and 100 m of writing was performed using a writing tester described in JIS S6039 (ISO12757-1) at a writing angle of 65°, a writing load of 100 g (0.98 N), and a writing speed of 4 m / min. Then, using a surface property tester (product name: HEIDON-14D, manufactured by Shinto Scientific Co., Ltd.), the writing resistance was measured when a straight line was written on fine paper (equivalent to writing paper A specified in the old JIS P3201; made from 100% chemical pulp, with a basis weight range of 40 to 157 g / m2 and a whiteness of 75.0% or more) under conditions of a writing angle of 70°, 4 m / min, and a writing load of 200 g (1.96 N).

[0012] (ink viscosity, ink consumption) In addition, simply setting the friction coefficient to 0.13 as above does not provide sufficient ink ejection and does not allow for thick writing. -1 The ink viscosity (when writing) needs to be 10,000 mPa·s or less. This improves ink discharge, produces thick handwriting, and provides a firmer writing feel (feel) When given more consideration, an ink viscosity of 8,000 mPa·s or less is more preferable, and even more preferably an ink viscosity of 6,000 mPa·s or less, with 5,000 mPa·s or less being even more preferable. On the other hand, if the ink viscosity is too low, such as less than 1000 mPa·s, the ball will slide too much, resulting in mistakes, a lack of a writing feel, and an unpleasant writing experience. It will also be likely to affect writing performance and pigment dispersibility, with symptoms such as bleed-through, bleeding, bleeding, and handwriting drying. Therefore, an ink viscosity of 1000 mPa·s or more is preferable, and even more preferably an ink viscosity of 2000 mPa·s or more, and even more preferably 3000 mPa·s or more. The ink viscosity is measured at a shear rate of 200 sec at 20°C. -1 The measurement was performed using a Brookfield Viscometer RVDVII+Pro CP-52 spindle.

[0013] By setting the friction coefficient and ink viscosity as described above, the ink consumption per 100 m of an oil-based ballpoint pen can be set to 30 mg or more, which allows for a firm writing feel (comfort), while also allowing for a large amount of ink consumption, resulting in thick handwriting, and good writing performance without line skips or smudges. From this perspective, it is preferable for the ink consumption to be 35 mg or more. On the other hand, if the ink consumption per 100 m of an oil-based ballpoint pen exceeds 100 mg, writing properties such as bleed-through, bleeding, smearing, and handwriting drying properties are likely to be affected, as well as ink tracking properties. Therefore, the ink consumption is preferably 100 mg or less, and from further consideration, it is more preferable to have the ink consumption be 90 mg or less, and more preferably 80 mg or less. Regarding ink consumption, a spiral writing test was conducted using five test samples at a writing speed of 4 m / min under the following conditions: temperature: 20°C, writing angle: 70°, writing load: 200 g on JIS P3201 writing paper. The average ink consumption per 100 m from the initial 0 to 100 m point was defined as the ink consumption per 100 m.

[0014] Furthermore, the friction coefficient was carefully examined, and the relationship between the friction coefficient during normal writing and slow writing was carefully examined. As a result, in order to obtain a thick handwriting while having a heavy writing feel and a firm writing feel (writing comfort), the ratio of the friction coefficient at a writing speed of 4 m / min at a writing load of 200 gf and a writing angle of 70° to the friction coefficient at a writing speed of 0.1 m / min at a writing load of 200 gf and a writing angle of 70° is preferably 0.8≦X / Y≦1.2. In order to obtain a more stable writing feel with a heavy writing feel and a firm writing feel (writing comfort), the ratio is preferably 0.85≦X / Y≦1.15, and more preferably 0.9≦X / Y≦1.1.

[0015] Furthermore, by setting the friction coefficient, ink viscosity, and ink consumption as described above, the ink consumption tends to be stable from the beginning to the end of writing, which is preferable because it suppresses wear on the ball seat, makes it difficult for the handwriting to smudge, and makes it easier to stably obtain good writing performance with thick handwriting. Specifically, when the ink consumption amount Amg from the initial 0 to 100 m is taken as being equal to the ink consumption amount Bmg 100 m before the end of the ink run, it is preferable that the ratio of the ink consumption amount Bmg 100 m before the end of the ink run to the ink consumption amount Amg from the initial 0 to 100 m is 0.8≦A / B≦1.2, and it is preferable that the ratio of the ink consumption amount Bmg 100 m before the end of the ink run is 0.9≦A / B≦1.1.

[0016] (resin) In the present invention, resins are used because they can provide a firm writing feel (writing comfort) and adjust the ink viscosity. Examples of resins include polyvinyl butyral resins, ketone resins, amide resins, terpene phenol resins, rosin resins, maleic acid resins, alkylphenol resins, styrene-maleic acid resins, ethylene-maleic acid resins, styrene-acrylic resins, acrylic resins, maleic acid resins, cellulose resins, petroleum resins, coumarone-indene resins, polyethylene oxide, polymethacrylic acid esters, ketone-formaldehyde resins, α- and β-pinene-phenol polycondensation resins, etc. These may be used alone or in combination of two or more.

[0017] Among these resins, in order to obtain a firm writing feel (comfort) while easily suppressing wear of the ball seat by providing a weighted writing feel without the ball sliding too much, it is preferable to select from rosin resin, ketone resin, and terpene phenol resin. Considering that the ink viscosity is unlikely to change significantly even if a large amount of resin is contained and that it is easy to obtain the effects of the present invention, it is preferable to select from rosin resin and ketone resin, and further, in consideration of a firm writing feel (comfort), it is preferable to select from rosin resin.

[0018] As for the rosin resin, examples include rosin ester, hydrogenated rosin ester, and polymerized rosin ester. From the viewpoint of obtaining a firmer writing feel (writing comfort), it is preferable to use rosin ester or hydrogenated rosin ester, and from further consideration, it is preferable to use rosin ester.

[0019] The softening point of the resin is preferably 50° C. or higher and 130° C. or lower in order to have a suitable elasticity and to easily obtain a firm writing feel (writing comfort), and is preferably 60° C. or higher and 120° C. or lower in consideration of a firmer writing feel (writing comfort) and suppression of wear of the ball seat, and more preferably 65° C. or higher and 110° C. or lower, and even more preferably 70° C. or higher and 100° C. Here, the softening point of the resin is a value measured in accordance with JIS K2207.

[0020] In order to easily obtain the effects of the present invention, the upper limit of the acid value of the resin is preferably 50 mgKOH / g or less, and more preferably 30 mgKOH / g or less, and from further consideration, more preferably 15 mgKOH / g or less, and more preferably 10 mgKOH / g or less, and the lower limit is preferably 0.1 mgKOH / g or more, and more preferably 5 mgKOH / g or more. The acid value is the number of milligrams of potassium hydroxide required to neutralize the acid groups contained in 1 g of resin, and can be measured by any known method, generally in accordance with JIS K0070.

[0021] If the resin content is less than 5% by mass relative to the total amount of the ink composition, it is difficult to obtain a sufficient effect of suppressing wear of the ball seat while obtaining a firm writing feel (writing comfort), so it is preferably 5% by mass or more, and more preferably 10% by mass or more, and more preferably 15% by mass or more. Also, if the resin content relative to the total amount of the ink composition exceeds 50% by mass, the solubility in the ink is likely to be poor, and furthermore, the ink viscosity becomes too high, which tends to reduce the ink consumption and affect the writing feel and writing performance, so it is preferably 40% by mass or less, and more preferably 35% by mass or less, and more preferably 30% by mass or less.

[0022] (Organic solvent) Examples of the organic solvent used in the present invention include organic solvents that are generally used as inks for writing instruments, such as glycol ether solvents such as 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, diethylene glycol dimethyl ether, 3-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; and alcohol solvents such as benzyl alcohol, methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t-butanol, propargyl alcohol, allyl alcohol, 3-methyl-1-butyn-3-ol, ethylene glycol monomethyl ether acetate, and other higher alcohols.

[0023] Among these organic solvents, it is preferable to use glycol ether solvents because the effect of the present invention can be easily obtained in consideration of the solubility with colorants, resins, and surfactants. This is because the ink is stable over time even when stored for a long period of time due to the stable dissolution. Furthermore, when glycol ether solvents are used, the strength of the coating formed when the tip end dries is softened and writing performance is easily improved because they are easily absorbed by moisture, and it is more effective to use them in combination with a surfactant to be described later, and in consideration of the stability in the ink, it is preferable to use aromatic glycol ether solvents. Furthermore, it is preferable to use alcohol solvents for organic solvents other than glycol ether solvents, because alcohol solvents evaporate and tend to dry at the tip end, and the inside of the writing tip (inside the tip end) is thickened more quickly, thereby suppressing ink leakage from the gaps at the writing tip, and improving the ink leakage suppression performance, which is preferable. Furthermore, aromatic alcohols such as benzyl alcohol also have the effect of improving lubricity, so it is preferable to use at least one of them.

[0024] In addition, in consideration of improving solubility, strike-through, handwriting drying properties, bleeding, etc., the content of the organic solvent is preferably 10 mass % or more and 90 mass % or less, and more preferably 25 mass % or more and 80 mass % or less, based on the total amount of the ink composition.

[0025] (Coloring agent) The colorant used in the ink composition for oil-based ballpoint pens of the present invention is not particularly limited and may be a dye, a pigment, or the like, and may be appropriately selected for use. Dyes and pigments may be used in combination.

[0026] Dyes used in the oil-based ink composition include oil-soluble dyes, acid dyes, basic dyes, metal-containing dyes, and the like, and various salt-forming dyes thereof, such as salt-forming dyes of acid dyes and basic dyes, salt-forming dyes of organic acids and basic dyes, salt-forming dyes of acid dyes and organic amines, etc. Among them, it is preferable to use salt-forming dyes because they have a moderate elasticity and therefore can provide a firm writing feel (writing comfort), and further, considering that the effect of the present invention can be easily obtained by maintaining stability over time due to the stable salt-forming bond, it is preferable to select from salt-forming dyes of basic dyes and organic acids, salt-forming dyes of acid dyes and basic dyes, and salt-forming dyes of acid dyes and organic amines. Dyes include Balifast Black 1802, Balifast Black 1805, Balifast Black 1807, Balifast Violet 1701, Balifast Violet 1704, Balifast Violet 1705, Balifast Blue 1601, Balifast Blue 1605, Balifast Blue 1613, Balifast Blue 1621, Balifast Blue 1631, Balifast Red 1320, Balifast Red 1355, Balifast Red 1360, Balifast Yellow 1101, Balifast Yellow 1151, Nigrosine Base EXBP, Nigrosine Base EX, BASE OF BASIC DYES ROB-B, BASE OF BASIC DYES RO6G-B, 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.), Aizen Spiron Black GMH-Special, Aizen Spiron Violet C-RH, Aizenspiron Blue GNH, Aizenspiron Blue 2BNH, Aizenspiron Blue C-RH, Aizenspiron Red C-GH, Aizenspiron Red C-BH, Aizenspiron Yellow C-GNH, Aizenspiron Yellow C-2GH, SPT Blue 111, SPT Blue GLSH-Special, SPT Red 533, SPT Orange 6, SBN Yellow 510, SBN Yellow 530, SRC-BH (all manufactured by Hodogaya Chemical Co., Ltd.). Examples of pigments include inorganic, organic, and processed pigments. Specific examples of pigments include carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine-based, azo-based, quinacridone-based, diketopyrrolopyrrole-based, quinophthalone-based, threne-based, triphenylmethane-based, perinone-based, perylene-based, dioxazine-based, metallic pigments, pearl pigments, fluorescent pigments, and phosphorescent pigments. These dyes and pigments may be used alone or in combination of two or more kinds.

[0027] In addition, it is preferable to use a pigment as a colorant. This is because, in the case of a ballpoint pen, the pigment particles enter the gap between the ball and the tip body, which makes it easier for the pigment particles to act like a bearing, and by suppressing metal contact, it is easier to improve lubricity and suppress wear of the ball seat, so it is preferable to use a pigment. In the present invention, the use of a resin and a pigment makes it easier to obtain the effect of suppressing wear of the ball seat, so it is more effective to use a pigment. Furthermore, it is preferable because the synergistic effect of the lubricating layer made of a surfactant, which will be described later, the pigment particles, and the resin makes it easier to suppress wear of the ball seat and improve the writing feel.

[0028] The average particle size of the pigment is preferably 1 nm or more and 500 nm or less, more preferably 30 nm or more and 350 nm or less, and even more preferably 50 nm or more and 300 nm or less. By setting the average particle size in the above range, the slipperiness is improved, which makes it easier to obtain the effect of suppressing the wear of the ball seat and improving the writing feel. Here, the average particle size can be determined by a laser diffraction method, specifically, by a laser diffraction particle size distribution analyzer (product name "MicrotracHRA9320-X100", Nikkiso Co., Ltd.), using the particle size (D50) at 50% cumulative volume of particle size distribution measured based on values ​​calibrated using standard samples or other measurement methods. Since the pigment exerts the above-mentioned effects in a dispersed state in the ink composition for oil-based ballpoint pens, it is preferable to determine the particle size in the dispersed state.

[0029] As for the type of pigment, it is preferable to use carbon black, quinacridone-based, threne-based, and diketopyrrolopyrrole-based pigments. Furthermore, in consideration of suppressing line skipping and handwriting smearing and suppressing wear of the ball seat, it is preferable to use carbon black and diketopyrrolopyrrole-based pigments.

[0030] The content of the colorant is preferably 5% by mass or more and 50% by mass or less based on the total amount of the ink composition. This is because if it is less than 5% by mass, it tends to be difficult to suppress the wear of the ball seat and to obtain thick handwriting, and if it exceeds 50% by mass, it tends to affect the solubility in the ink. Taking this tendency into consideration, the content is preferably 7% by mass or more and 45% by mass or less, and further taking this into consideration, it is preferably 10% by mass or more and 45% by mass or less.

[0031] (Surfactant) In the present invention, it is preferable to use a surfactant, because it is easy to set the coefficient of friction to 0.13 or more, and it is easy to obtain a firm writing feel (feel) with a heavy writing feel, and further, by using a resin and a surfactant in combination, it is easy to set the coefficient of friction to 0.13 or more, and it is easy to obtain the above-mentioned effects. Furthermore, when a resin is used as in the present invention, it is preferable to use a surfactant because it has the effect of improving the writing performance when the writing tip (tip tip) is left in the air and the writing tip (tip tip) dries. This is because the use of a surfactant tends to soften the coating film formed, improving the writing performance and further improving the lubricity, making it easier to suppress the wear of the ball seat. In particular, when the content of the resin is increased to 10% by mass or more relative to the total amount of the ink composition, it is effective because it tends to affect the writing performance, and 15% by mass or more is more effective, and 20% by mass or more is more effective. Examples of surfactants include silicone surfactants, fluorine surfactants, phosphate surfactants, polyoxyalkylene alkyl ethers, fatty acids, and fatty acid esters. Among them, in consideration of the above effects, it is preferable to select from phosphate surfactants, fatty acids, and fatty acid esters. Furthermore, in consideration of a firm writing feel (writing comfort), wear inhibition of the ball seat, and writing performance, it is preferable to select from phosphate surfactants and fatty acids, and in consideration of more, phosphate surfactants are preferable.

[0032] Specific examples of phosphate surfactants include those having an alkoxyethyl group (C n H 2n+1 OCH2CH2O) or alkoxy groups (C m H 2m+1 O), a phosphate ester having the formula (I) or (II), a phosphate monoester of a polyoxyethylene alkyl ether or a polyoxyethylene alkylaryl ether, a phosphate diester of a polyoxyethylene alkyl ether or a polyoxyethylene alkylaryl ether, a phosphate triester of a polyoxyethylene alkyl ether or a polyoxyethylene alkylaryl ether, an alkyl phosphate ester, an alkyl ether phosphate ester, or a derivative thereof.

[0033] Specific examples of phosphate ester surfactants include the phoslex series (manufactured by SC Organic Chemical Co., Ltd.), the JP series (manufactured by Johoku Chemical Industry Co., Ltd.), the Plysurf series (manufactured by Daiichi Kogyo Co., Ltd.), the Phosphanol series (manufactured by Toho Chemical Industry Co., Ltd.), and the NIKKOL series (manufactured by Nikko Chemicals Co., Ltd.).

[0034] Among the phosphate ester surfactants, alkoxyethyl groups (C n H 2n+1 O-C2H4O) or alkoxy groups (C m H 2m+1 O), phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, and phosphoric acid diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers.

[0035] Furthermore, among the phosphate ester surfactants, in order to improve the writing feel (writing comfort) and writing performance, it is recommended to use alkoxyl groups (C m H 2m+1It is preferable to use a phosphate surfactant having an alkoxy group (C m H 2m+1 O), it becomes easier for the ink to wet and spread evenly, and it also has a compatible relationship with the resin, which makes it easier to improve writing performance. In addition, in order to achieve a firmer writing feel (writing comfort) and to suppress wear of the ball seat, an alkoxyethyl group (C n H 2n+1 It is preferable to use a phosphate ester surfactant having the formula (O-C2H4O).

[0036] The phosphate ester surfactant has an alkoxyethyl group (C n H 2n+1 O-C2H4O) or alkoxy groups (C m H 2m+1 The carbon chain (n, m) of the terminal alkyl group of the alkoxyethyl group (C n H 2n+1 O-C2H4O) or alkoxy groups (C m H 2m+1 When the carbon chain (n, m) of the terminal alkyl group of O) has an appropriate length, the above-mentioned effect is easily maintained, so the carbon chain (n, m) of the terminal alkyl group is preferably 1 or more and 20 or less, and more preferably 4 or more and 18 or less. In order to improve the writing feel (writing comfort) and writing performance, the carbon chain (n, m) is preferably 8 or more and 20 or less, and the carbon chain (n, m) is preferably 10 or more and 18 or less, or 12 or more and 18 or less. In addition, in consideration of a more solid writing feel (writing comfort) and suppression of wear of the ball seat, the carbon chain (n, m) is preferably 1 or more and 15 or less, and the carbon chain (n, m) is preferably 3 or more and 10 or less, or 3 or more and 6 or less.

[0037] Furthermore, among the phosphate surfactants, in consideration of improving the slipperiness, suppressing wear of the ball seat, and improving the writing performance and writing feel, it is preferable to use a phosphate surfactant having an alkyl group, and in particular, the number of carbon atoms contained in the alkyl group is preferably 8 to 18, more preferably 10 to 18, and even more preferably 12 to 18. This is because if the number of carbon atoms in the alkyl group is too small, the slipperiness tends to be insufficient, and if the number of carbon atoms is too large, the stability over time tends to be affected.

[0038] Furthermore, when a phosphate ester surfactant is used, the acid value is preferably 150 (mgKOH / g) or less, more preferably 120 (mgKOH / g) or less, and even more preferably 100 or less, in order to facilitate the improvement in slipperiness due to the phosphate ester surfactant. Furthermore, in consideration of stability and lubricity in the oil-based ballpoint pen ink composition, the acid value is preferably 30 (mgKOH / g) or more and 150 (mgKOH / g) or less, preferably 40 (mgKOH / g) or more and 120 (mgKOH / g) or less, and more preferably 40 (mgKOH / g) or more and 100 (mgKOH / g) or less. The acid value is expressed as the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of sample.

[0039] The content of the surfactant is more preferably 0.1% by mass or more and 5.0% by mass or less based on the total amount of the ink composition for oil-based ballpoint pens. This is because if it is less than 0.1% by mass, it is difficult to improve the slipperiness, thereby suppressing the wear of the ball seat, and improving the writing performance and writing feel, and if it exceeds 5.0% by mass, the ink tends to become unstable over time. Taking these factors into consideration, the content of the surfactant is preferably 0.3% by mass or more and 4.0% by mass or less based on the total amount of the ink composition for oil-based ballpoint pens, and more preferably 0.5% by mass or more and 3.0% by mass or less.

[0040] (Organic amine) In the present invention, when a surfactant such as a phosphate surfactant is used, neutralization is preferred because it dissolves and stabilizes in the ink, and the effects of the present invention can be stably obtained. Examples of organic amines include amines having ethylene oxide such as oxyethylene alkylamines and polyoxyethylene alkylamines, alkylamines such as laurylamine and stearylamine, aliphatic amines such as dimethyl alkylamines such as distearylamine, dimethyl laurylamine, dimethyl stearylamine and dimethyl octylamine, and alkanolamines such as diethanolamine and triethanolamine. Among these, aliphatic amines or amines having ethylene oxide are preferred in consideration of the effects of the present invention, and aliphatic amines are preferred in consideration of ink stability. These may be used alone or in combination of two or more.

[0041] Furthermore, the total amine value of the organic amine is preferably 300 (mgKOH / g) or less, taking into consideration the stability with colorants, resins, surfactants and other components. If it exceeds 300 (mgKOH / g), the reactivity is strong, and it is likely to affect the above components, and therefore it is likely to affect the ink stability over time, so from this point of view, the total amine value is preferably 250 (mgKOH / g) or less. On the other hand, from the above-mentioned effects in mind, the lower limit of the total amine value is preferably 100 (mgKOH / g) or more, and from this point of view, the total amine value is preferably 150 (mgKOH / g) or more, and more preferably 200 (mgKOH / g) or more. The total amine value indicates the total amount of primary, secondary, and tertiary amines, and is expressed as the number of milligrams of potassium hydroxide equivalent to the amount of hydrochloric acid required to neutralize 1 g of sample.

[0042] The content of the organic amine is preferably 0.1 mass % or more and 10 mass % or less based on the total amount of the ink composition, taking into consideration the stability with the colorant, resin, surfactant, and other components, and further preferably 0.5 mass % or more and 5 mass % or less, taking into consideration neutralization of the surfactant described above.

[0043] In addition, as viscosity adjusters, pseudoplasticity imparting agents such as fatty acid amides and hydrogenated castor oil, colorant stabilizers, plasticizers, chelating agents, water, etc. may be appropriately used. These may be used alone or in combination of two or more kinds.

[0044] (Ballpoint pen) For ballpoint pen tips, it is preferable to maintain lubricity between the ball and the tip body, prevent smearing of handwriting, and suppress wear on the ball seat to improve the writing feel, and to provide a ball seat with an approximately arc-shaped surface on the bottom wall of the ball-holding chamber.

[0045] In addition, the arithmetic mean roughness (Ra) of the ball surface of the ballpoint pen tip used in the present invention is preferably 0.1 nm or more and 12 nm or less. This is because when the arithmetic mean roughness (Ra) is in the above range, the ink is easily applied to the ball surface, thick handwriting is easily obtained, and the wear suppression effect of the ball seat is easily obtained. From further consideration, the arithmetic mean roughness (Ra) is preferably 0.1 nm or more and 10 nm or less, more preferably 1 nm or more and 8 nm or less. The surface roughness can be measured using a model named SPI3800N manufactured by Seiko Epson Corporation.

[0046] The material used for the balls is not particularly limited, but examples include cemented carbide balls mainly composed of tungsten carbide, metal balls such as stainless steel, ceramic balls such as silicon carbide, silicon nitride, alumina, silica, and zirconia, and ruby ​​balls.

[0047] In addition, materials for ballpoint pen tips include metal materials such as stainless steel, nickel silver, brass, aluminum bronze, and aluminum, and resin materials such as polycarbonate, polyacetal, and ABS, but considering wear of the ball seat and stability over time, it is preferable to use a stainless steel tip body.

[0048] In addition, the movement amount of the ball in the ballpoint pen tip used in the present invention in the vertical direction is preferably 3 μm or more and 25 μm or less. This is because, within the above range, it is possible to increase the ink consumption while maintaining a firm writing feel (writing comfort), and it is easy to produce thick handwriting. From a more detailed consideration, the movement amount of the ball in the ballpoint pen tip in the vertical direction is preferably 3 μm or more and 22 μm or less, more preferably 5 μm or more and 20 μm or less, and even more preferably 7 μm or more and 18 μm or less.

[0049] When ink is directly stored in the ink storage cylinder, the rear end of the ink can be filled with an ink backflow prevention material. The ink backflow preventive composition comprises a non-volatile liquid or a low-volatility liquid. Specific examples include petrolatum, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefin, α-olefin oligomer or cooligomer, dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, polyether-modified silicone oil, fatty acid-modified silicone oil, and the like, and one or more of these can be used in combination. (Example)

[0050] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0051] Example 1 The ink composition for an oil-based ballpoint pen in Example 1 was prepared by collecting the colorant, organic solvent, phosphate ester surfactant, organic amine, and resin at 60°C using a Disper stirrer, stirring and dissolving the mixture, and then cooling to room temperature to obtain an ink composition for an oil-based ballpoint pen. The specific blending amounts are as follows:

[0052] Colorant (salt-forming dye of organic acid and basic dye) 25.0% by mass Colorant (salt-forming dye of organic acid and basic dye) 15.0% by mass Alcohol solvent (benzyl alcohol) 20.4% by mass Glycol ether solvent (ethylene glycol monophenyl ether) 13.6% by mass Rosin resin (rosin ester, softening point: 82°C) 20.0% by mass Alkoxy group (C m H 2m+1 O) 3.0% by mass of a phosphate ester surfactant Organic amine (polyoxyethylene alkylamine) 3.0% by mass

[0053] Examples 2 to 19 As shown in Table 1, except for changing the ink components, oil-based ballpoint pen ink compositions of Examples 2 to 19 were obtained in the same manner as in Example 1. The measurement and evaluation results are shown in the table.

[0054] Comparative Examples 1 to 4 As shown in the table, except that the ink components were changed, the ink compositions for oil-based ballpoint pens of Comparative Examples 1 to 4 were obtained in the same manner as in Example 1. The measurement and evaluation results are shown in the table.

[0055] The ink viscosity in the examples was measured at a shear rate of 200 sec in an environment of 20°C. -1 The ink viscosity was measured using a Brookfield Viscometer RVDVII+Pro CP-52 spindle. The coefficient of friction in the examples was calculated from the writing resistance measured by the above-mentioned measuring method and the following formula: Friction coefficient (dynamic friction coefficient) = writing resistance (dynamic friction force) / writing load (normal force) In addition, the ink consumption was calculated by performing a spiral writing test using five test samples at a writing speed of 4 m / min on JIS P3201 writing paper at 20°C, with a writing angle of 70° and a writing load of 200 g, and by calculating the average ink consumption per 100 m.

[0056] Testing and Evaluation The ink compositions for oil-based ballpoint pens prepared in Examples 1 to 19 and Comparative Examples 1 to 4 were directly placed in the ink holder tube by mounting a ballpoint pen tip rotatably holding a ball (φ0.7 mm) of the ballpoint pen tip, the ball being pressed against the inner wall of the tip end edge by a resilient member, at the tip of an ink holder tube (made of polypropylene). The ink compositions for oil-based ballpoint pens (0.3 g) prepared in Examples 1 to 19 and Comparative Examples 1 to 4 were directly placed in the ink holder tube, and the ballpoint pen refill was placed in an oil-based ballpoint pen manufactured by Pilot Corporation to prepare an oil-based ballpoint pen. The following tests and evaluations were carried out using JIS P3201 writing paper as the writing test paper. [Table 1] [Table 2]

[0057] In addition, for the ballpoint pens of Examples 1 to 19 and Comparative Examples 1 to 4, the friction coefficient X (when writing normally) at a writing speed of 4 m / min, a writing load of 200 gf, a writing angle of 70°, and the friction coefficient Y (when writing slowly) at a writing speed of 0.1 m / min, a writing load of 200 gf, a writing angle of 70° were measured and evaluated as a writing stability test (writing resistance stability test) as described below. Some of the specific measured values ​​and measurement ratios are shown below for the ballpoint pens of Examples 1 to 3 and Examples 10 to 13. Example 1 X=0.18, Y=0.17, X / Y=1.06 Example 2 X=0.18, Y=0.18, X / Y=1.00 Example 3: X=0.19, Y=0.18, X / Y=1.06 Example 10 X=0.18, Y=0.18, X / Y=1.00 Example 11 X=0.19, Y=0.18, X / Y=1.06 Example 12 X=0.18, Y=0.18, X / Y=1.00 Example 13 X=0.19, Y=0.18, X / Y=1.06

[0058] In addition, for the ballpoint pens of Examples 1 to 3 and 6, the ink consumption Amg from the initial 0 to 100 m point was measured, and the ink consumption Bmg 100 m before the ink runs out was measured. The ratio of the ink consumption Amg from the initial 0 to 100 m point to the ink consumption Bmg 100 m before the ink runs out was measured, and is shown below. Example 1 A=45, B=47, A / B=0.96 Example 2 A=35, B=34, A / B=1.02 Example 3 A=44, B=41, A / B=1.07 Example 6 A=40, B=41, A / B=0.98

[0059] Writing comfort test: A sensory test was conducted by handwriting to test the writing comfort. ◎ Firm writing feel ○ The writing feel is a bit slippery, but it is solid. △...Slippery writing feel ×...The writing feel is too slippery

[0060] Thickness of handwriting: Handwritten handwriting was observed. ◎ Thick and clear handwriting ○ Thick handwriting △: Handwriting that is thick enough that it does not cause any problems in practical use. ×: Light handwriting

[0061] Abrasion resistance test (wear test of ball seat): Wear of the ball seat after the writing test was measured using a running test machine with a load of 200gf, a writing angle of 70°, and a speed of 4m / min. ◎ The wear of the ball seat is less than 5μm ○...Ball seat wear is 5μm or more and less than 10μm △: Wear of the ball seat is between 10μm and 20μm, but writing is possible. × The ball seat is badly worn, causing poor writing.

[0062] Writing stability test (writing resistance stability test) The coefficient of friction at a writing speed of 4 m / min, with a writing load of 200 gf and a writing angle of 70°, was defined as X (normal writing), and the coefficient of friction at a writing speed of 0.1 m / min, with a writing load of 200 gf and a writing angle of 70°, was defined as Y (slow writing). ◎ 0.9≦X / Y≦1.1 ○ 0.8≦X / Y<0.9 or 1.1 <X / Y≦1.2 △ 0.7≦X / Y<0.8 or 1.2 <X / Y≦1.3 ×...X / Y<0.7 or X / Y>1.3

[0063] Writing performance test: After handwriting, the pen was left in an environment of 20°C and 65% RH for 24 hours with the tip extended, and then a running test was performed under the writing conditions listed below, and the length of the smudged handwriting at the start of writing was measured. <Writing conditions> The pen was evaluated by writing a straight line using a running test machine under the following conditions: writing load 200gf, writing angle 70°, writing speed 4m / min. ◎ The length of the smudged handwriting is less than 5 mm ○ The length of the smudged handwriting is 5mm or more but less than 10mm △: The length of the smudged handwriting is 10mm or more but less than 20mm × The length of the smudged handwriting is 20mm or more

[0064] In Examples 1 to 19, good performance was obtained in the writing comfort test, handwriting darkness, abrasion resistance test (ball seat abrasion test), writing stability test (writing resistance stability test), and writing start performance test.

[0065] In Comparative Example 1, the coefficient of friction was low, resulting in an excessively slippery writing feel, and the writing stability test was also poor. In Comparative Example 2, the ink viscosity was high, so the handwriting was thin and the writing performance was poor. In Comparative Example 3, the ink consumption was small, so the handwriting was faint, and furthermore, the writing comfort test and writing stability test were poor.

[0066] In addition, in this embodiment, an oil-based ballpoint pen in which a ballpoint pen refill containing an oil-based ballpoint pen ink composition in an ink holding tube is disposed in the barrel has been exemplified, but the writing instrument of the present invention may be a writing instrument in which the barrel itself is the ink holding tube and the ink composition for an oil-based ballpoint pen is directly held in the barrel, which is a direct-loading type ballpoint pen, or a structure in which an ink holding tube containing an ink composition for an oil-based ballpoint pen (ballpoint pen refill) is used as a ballpoint pen as is. [Industrial Applicability]

[0067] The present invention can be used as an oil-based ballpoint pen ink composition, and more specifically, can be widely used as a cap-type, knock-type, or other oil-based ballpoint pen filled with the oil-based ballpoint pen ink composition.

Claims

1. An oil-based ballpoint pen having a ballpoint tip at the tip of an ink reservoir, and containing an ink composition for an oil-based ballpoint pen, the ink composition comprising a colorant, an organic solvent, and a resin, The ink viscosity of the ink composition for oil-based ballpoint pens is 200° C. at a shear rate of 200 sec. －１ In the above, the viscosity is 1000 mPa·s or more and 10000 mPa·s or less, The oil-based ballpoint pen has a friction coefficient of 0.13 or more at a writing speed of 4 m / min under a writing load of 200 gf and a writing angle of 70°; An oil-based ballpoint pen having an ink consumption of 30 mg or more and 100 mg or less per 100 m.

2. 2. The oil-based ballpoint pen according to claim 1, characterized in that the ratio of the friction coefficient at a writing speed of 4 m / min, a writing load of 200 gf, a writing angle of 70°, and a writing speed of 0.1 m / min, which is defined as X and Y, is 0.8≦X / Y≦1.

3.

3. 3. The oil-based ballpoint pen according to claim 1, wherein the resin is selected from the group consisting of rosin resin, ketone resin, and terpene phenol resin.

4. 3. The oil-based ballpoint pen according to claim 1, wherein the softening point of the resin is 50° C. or higher and 130° C. or lower.

5. 3. The oil-based ballpoint pen according to claim 1, wherein the resin content is from 10% by mass to 40% by mass.

6. 3. The oil-based ballpoint pen according to claim 1, wherein the surfactant is a phosphate surfactant or a fatty acid.

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