Oil-based ballpoint pen

Abstract

An oil-based ballpoint pen (100) comprises an ink reservoir tube (2), which has a ballpoint pen tip (4) at an end thereof, and, contained in the ink reservoir tube (2), an ink composition (10) for oil-based ballpoint pens which comprises a colorant, an organic solvent having a boiling point of 140°C or lower, and a resin. The ink composition (1) for oil-based ballpoint pens has an ink viscosity, as measured at 20°C and a shear rate of 200 sec-1, of 300 mPa·s or less. The oil-based ballpoint pen (100) has an ink consumption of 80 mg or greater per 100 m of writing distance, and the ratio of the ball diameter B (mm) to the ink consumption A (mg) per 100 m of writing distance is such that 100<A / B<600.

Description

[Technical Field]

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

[0002] 2. Description of the Related Art A ballpoint pen having a ballpoint pen tip that rotatably holds a ball at the tip of an ink tube is known as a writing instrument capable of writing on a permeable surface such as paper.

[0003] Furthermore, marking pens, whose brush tip is generally made of a fiber bundle, are known as writing implements capable of writing on non-permeable surfaces such as plastic materials and craft tape. Marking pens are widely used for writing on non-permeable surfaces. However, these marking pens have various issues and room for improvement.

[0004] Marking pens are very susceptible to breakage and deformation because the brush tip is made of a fiber bundle. When the brush tip is made of a fiber bundle, the contact with the writing surface is surface contact, making it possible to write bold characters. Furthermore, when writing on non-permeable surfaces, ink can be applied sufficiently according to the movement of the brush tip, as there is no need to rely on the rotation of the ball as with a typical ballpoint pen. However, the tip of a fiber bundle is prone to breakage and deformation when writing, and a consistent writing width cannot be guaranteed over long periods of use. In particular, when writing on non-permeable surfaces such as plastic materials or craft tape, brush tips made of a fiber bundle are prone to deformation (see, for example, Patent Documents 1 and 2).

[0005] To solve these problems with marking pens, various attempts have been made to form the brush tip not as a fiber bundle but as a ballpoint pen tip made of metal or resin, like a ballpoint pen. However, simply changing the brush tip from a marking pen structure to a ballpoint pen structure and using a ballpoint pen tip made of metal or resin, like a conventional oil-based ballpoint pen (see, for example, Patent Document 3), creates problems that cannot be completely solved on non-permeable surfaces, such as plastic materials and craft tape.

[0006] In addition, ballpoint pen inks with an ink consumption of 32 mg to 47 mg per 200 m (equivalent to 16 to 23.5 mg per 100 m) can be used to write on paper, but the resulting writing is not dense enough. Furthermore, when writing on a non-permeable surface (such as a plastic surface), the ink does not adhere to the non-permeable surface, resulting in various problems (see, for example, Patent Document 4).

[0007] Furthermore, increasing the amount of ink consumed can easily affect writing performance, such as drying time, blobbing, and bleeding. Also, if the tip end is left exposed to the air, the solvent in the ink evaporates, and when the colorant and resin dry and solidify, writing tends to become smudged when writing begins (writing performance). This is particularly true for retractable ballpoint pens, such as knock-type ballpoint pens and twist-type ballpoint pens, where writing performance is easily affected, creating new problems. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-056946 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-176438 [Patent Document 3] Japanese Patent Application Publication No. 10-95948 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-153199 Summary of the Invention [Problem to be solved by the invention]

[0009] In consideration of these problems, the present invention has been made possible to solve the above problems by carefully examining the ink consumption (ballpoint pen specifications) and ink properties and ink components (ink specifications) for oil-based ballpoint pen specifications.

[0010] An object of the present invention is to provide an oil-based ballpoint pen that can be written on not only paper but also non-porous surfaces while maintaining a dark handwriting and has good writing properties. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention "1. An oil-based ballpoint pen having a ballpoint pen tip at the tip of an ink reservoir, and containing an ink composition for an oil-based ballpoint pen, the ink composition containing a colorant, an organic solvent having a boiling point of 140°C or less, a resin, and a surfactant, wherein the ink viscosity of the ink composition for an oil-based ballpoint pen is 20°C, a shear rate of 200 sec -1 The ink consumption of the oil-based ballpoint pen per 100 m of writing distance is 80 mg or more, and the ratio of the ink consumption A (mg) per 100 m of writing distance to the ball diameter B (mm) is 100 Either 1, wherein the hydroxyl value of the terpene phenol resin is 100 mgKOH / g or more 17 0mgKOH / g or less The styrene-maleic acid resin and Styrene-acrylic resin The acid value of the The acid value of the acrylic resin is 80 mgKOH / g An oil-based ballpoint pen characterized by the above. 2. The oil-based ballpoint pen described in paragraph 1, characterized in that the surfactant is one or more selected from phosphate ester surfactants, silicone surfactants, surfactants having an acetylene bond, fluorine-based surfactants, fatty acids, and fatty acid esters. 3. The oil-based ballpoint pen according to item 1 or 2, characterized in that the HLB value of the surfactant is 12 or less. 4. The oil-based ballpoint pen according to claim 1, wherein the ink composition for the oil-based ballpoint pen further contains an organic solvent having a boiling point of 160°C or higher. ​5. The oil-based ballpoint pen according to claim 1, wherein the ink composition for the oil-based ballpoint pen further contains silica. 6. The oil-based ballpoint pen according to claim 5, wherein the specific surface area of the silica is 30 m 2 / g or more and 300 m 2 / g or less. 7. The oil-based ballpoint pen according to claim 5, wherein the average primary particle diameter of the silica is 5 nm or more and 50 nm or less. 8. The oil-based ballpoint pen according to claim 1, wherein the movement amount of the ball of the ballpoint pen tip in the extending direction of the ink storage cylinder is 10 μm or more and 50 μm or less.

Advantages of the Invention

[0012] An oil-based ballpoint pen can be provided which increases the ink consumption and enables writing not only on paper but also on non-permeable surfaces while maintaining a dark handwriting, and has good writing properties such as no bleeding, no blotting, no smudging, and good drying property.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is a cross-sectional view of an example of a ballpoint pen. [Figure 2] ]FIG. 2 is an enlarged cross-sectional view of an example of a ballpoint pen tip.

Modes for Carrying Out the Invention

[0014] The oil-based ballpoint pen of the present invention has a ballpoint pen tip at the tip of an ink storage cylinder, and an ink composition for an oil-based ballpoint pen containing a colorant, an organic solvent having a boiling point of 140 °C or lower, a resin, and a surfactant is stored in the ink storage cylinder. Further, the ink viscosity of the ink composition for the oil-based ballpoint pen is 300 mPa·s or less at 20 °C and a shear rate of 200 sec -1 , the ink consumption per 100 m of the writing distance of the oil-based ballpoint pen is 80 mg or more, and the ratio of the ball diameter B (mm) to the ink consumption A (mg) per 100 m of the writing distance is 100 < A / B < 600.

[0015] In the present invention, the ink viscosity of the ink composition for an oil-based ballpoint pen is 20°C, a shear rate of 200 sec -1 The viscosity is 300 mPa·s or less, and the ink consumption per 100 m of writing distance of an oil-based ballpoint pen is 80 mg or more. This allows writing on non-porous surfaces as well as paper while maintaining a thick handwriting. Also, the ratio of the ink consumption A (mg) per 100 m of writing distance to the ball diameter B (mm) is 100

[0016] (ink viscosity) The oil-based ballpoint pen ink composition of the present invention was measured at 20°C and a shear rate of 100 sec -1 The ink viscosity (when writing) is 300 mPa·s or less. Because the ink viscosity of the oil-based ballpoint pen ink composition is 300 mPa·s or less, it is possible to write thick handwriting and on non-permeable surfaces, and it is possible to improve the smearing of handwriting.

[0017] The ink viscosity of an ink composition for an oil-based ballpoint pen is preferably 200 mPa·s or less, considering darker handwriting and good writeability on non-penetrable surfaces; 100 mPa·s or less is preferable, and 50 mPa·s or less is more preferable, considering writeability on more non-penetrable surfaces. The ink viscosity of an ink composition for an oil-based ballpoint pen is preferably 5 mPa·s or more, considering writeability such as blobbing, bleeding, and writing drying, and is even more preferable, and 8 mPa·s or more is more preferable. The ink viscosity of an ink composition for an oil-based ballpoint pen is measured at 20°C using a Brookfield Viscometer RVD VII+Pro CP-42 spindle.

[0018] (ink consumption)​ The ink consumption of the oil-based ballpoint pen of the present invention per 100 m of writing distance is 80 mg or more. When the ink consumption per 100 m of writing distance is 80 mg or more, the ink consumption is large, making it possible to write thicker lines and on non-permeable surfaces, without smearing of the lines, and providing a good writing feel. From a more specific perspective, the ink consumption per 100 m of the oil-based ballpoint pen is preferably 100 mg or more, and more preferably 110 mg or more. In order to make it possible to write thicker lines and on non-permeable surfaces and to prevent smearing of the lines, the ink consumption per 100 m of the oil-based ballpoint pen is preferably 130 mg or more.

[0019] Furthermore, the ink consumption is preferably 300 mg or less. If the ink consumption exceeds 300 mg, the gap between the ball and the tip end is likely to affect ink leakage prevention, and handwriting blobbing, bleeding, and dryness are likely to occur. Taking this into consideration, the ink consumption is preferably 250 mg or less. Considering the balance of the above effects, the ink consumption is preferably 100 mg or more and 250 mg or less. Considering the realization of darker handwriting, the ability to write on non-porous surfaces, and improved writing performance such as preventing smearing and blobbing, the ink consumption is preferably 110 mg or more and 250 mg or less, and more preferably 130 mg or more and 250 mg or less.

[0020] The ink consumption is measured by conducting a spiral writing test using five test samples at a writing speed of 4 m / min on JIS P3201 writing paper at a writing angle of 65° and a writing load of 100 g at 20°C. The average ink consumption per 100 m of writing distance in this spiral writing test is defined as the ink consumption per 100 m of writing distance.

[0021] In the present invention, in order to achieve thick handwriting while enabling writing on non-permeable surfaces and suppressing ink leakage, improving all aspects of writing performance such as writing feel, handwriting smear, bleeding, blotting, ink spread, and drying property, simply increasing the ink consumption is not sufficient. Therefore, it is necessary to examine the relationship between the ink consumption A (mg) of a ballpoint pen and the ball diameter B (mm).

[0022] In the oil-based ballpoint pen of the present invention, when the ink consumption per 100 m of writing distance is A (mg) and the ball diameter is B (mm), the relationship 100 < A / B < 600 is satisfied. In the oil-based ballpoint pen of the present invention, since A / B satisfies the above relationship, it is possible to write not only on paper but also on non-permeable surfaces while maintaining thick handwriting, suppress ink leakage, and improve writing performance such as handwriting smear, bleeding, blotting, ink spread, and drying property.

[0023] Regarding the relationship of 100 < A / B < 600 in the present invention, when A / B < 100, the ink consumption is not sufficient relative to the ball diameter, and thick handwriting cannot be obtained. Also, when A / B < 100, when writing on a non-permeable surface, handwriting smear and repellency occur, and a good writing feel cannot be obtained. When A / B > 600, bleeding, blotting, and ink spread occur, the handwriting drying property is also inferior, and ink leakage is likely to occur from the gap between the ball and the tip of the nib.

[0024] Considering improving thicker handwriting, writing performance on non-permeable surfaces (handwriting smear, blotting, ink spread, drying property), and writing feel, it is preferable to have the relationship 120 ≤ A / B < 600. To achieve the above effects well in a balanced manner, 155 ≤ A / B < 600 is preferable. Considering the writing performance on non-permeable surfaces (handwriting smear, blotting, ink spread, drying property), 180 ≤ A / B ≤ 550 is preferable, 250 ≤ A / B ≤ 520 is preferable, and 300 ≤ A / B ≤ 500 is preferable.

[0025] The ball diameter is not particularly limited, but is preferably about 0.1 mm or more and 2.0 mm or less, and more preferably in the range of 0.3 mm or more and 1.6 mm or less.

[0026] (Organic solvent) The ink composition for the oil-based ballpoint pen of the present invention contains an organic solvent with a boiling point of 140°C or lower. Because the ink composition for the oil-based ballpoint pen contains an organic solvent with a boiling point of 140°C or lower, when used to write on a non-permeable surface, it improves the drying properties of the ink and stabilizes the dissolution of the ink components. It also facilitates drying of the tip of the ballpoint pen, making it easier to prevent ink leakage from the gap between the ball and the tip. Taking these factors into consideration, the ink composition for the oil-based ballpoint pen preferably contains an organic solvent with a boiling point of 120°C or lower. Furthermore, considering the dissolution stability of the colorant, surfactant, and resin, and the drying properties of the ink, it preferably contains an alcohol solvent with a boiling point of 140°C or lower. Taking these effects into consideration, lower alcohols (with 5 or fewer carbon atoms in the molecule) are preferred, with lower alcohols with 3 or fewer carbon atoms in the molecule being more preferred.

[0027] Examples of organic solvents having a boiling point of 140° C. or less include alcohol solvents, glycol ether solvents, glycol solvents, hydrocarbon solvents, etc. Specific examples include methanol, ethanol, 1-propanol, isopropanol, isobutanol, butanol, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclopentane, n-heptane, isooctane, n-octane, isohexane, normal hexane, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and acetones.

[0028] In order to more easily obtain the above-mentioned effects, the content of the alcohol solvent is preferably 50% by mass or more of the total organic solvent content in the ink composition for an oil-based ballpoint pen, and from a more particular perspective, it is preferably 70% by mass or more, and more preferably 90% by mass or more.

[0029] The organic solvent preferably contains an organic solvent having a boiling point of 160° C. or higher. This is because the high boiling point makes it less likely to volatilize, improving the writing performance at the tip of the ballpoint pen and preventing whitening of handwriting.

[0030] Therefore, the ink composition for the oil-based ballpoint pen of the present invention preferably contains different types of organic solvents. In consideration of suppressing whitening of handwriting, the difference in boiling points of the different types of organic solvents is preferably 20°C or more, and more preferably 50°C or more, and more preferably 80°C or more.

[0031] In particular, when an alcohol solvent with a boiling point of 140°C or lower is used as the main agent, the handwriting may dry out rapidly, causing whitening of the handwriting. Therefore, using an organic solvent with a boiling point of 160°C or higher is effective in preventing rapid drying and whitening of the handwriting. From a more specific perspective, organic solvents with a boiling point of 170°C or higher are preferred, and organic solvents with a boiling point of 200°C or higher are more preferred. Furthermore, among the above organic solvents, glycol solvents are preferred.

[0032] In addition, to achieve a good balance between ink drying on non-permeable surfaces, ink leakage prevention, writing performance, and prevention of whitening of ink, it is preferable to use a combination of an alcohol solvent with a boiling point of 140°C or less and an organic solvent with a boiling point of 160°C or more.

[0033] Examples of organic solvents having a boiling point of 160° C. or less include alcohol solvents, glycol ether solvents, glycol solvents, and the like.

[0034] To facilitate the above-described effects, the content of organic solvents having a boiling point of 160°C or higher is preferably less than 20% by mass relative to the total content of organic solvents in the ink composition for oil-based ballpoint pens. From a more specific perspective, the content of organic solvents having a boiling point of 160°C or higher is preferably less than 10% by mass, and more preferably less than 5% by mass.

[0035] Regarding organic solvents, it is preferable to use a combination of an alcohol solvent with a boiling point of 140° C. or less and an organic solvent with a boiling point of 160° C. or more. It is also preferable to use a combination of a lower alcohol (with 5 or fewer carbon atoms in the molecule) and an organic solvent with a boiling point of 200° C. or more. By using organic solvents with these boiling points in combination, it is possible to achieve a good balance between handwriting drying on non-permeable surfaces, ink leakage prevention, writing performance, and prevention of handwriting whitening.

[0036] Furthermore, in consideration of improving solubility, writing drying properties, writing performance, etc., the content of the organic solvent is preferably from 10.0 to 90.0% by mass, and more preferably from 20.0 to 90.0% by mass, based on the total amount of the ink composition for oil-based ballpoint pens, and more preferably from 40.0 to 70.0% by mass, based on the total amount of the ink composition for oil-based ballpoint pens.

[0037] (coloring agent) The ink composition for the oil-based ballpoint pen of the present invention contains a colorant. The colorant used in the present invention is not particularly limited and may be a dye, a pigment, or the like, and may be appropriately selected and used. A dye and a pigment may be used in combination.

[0038] When the ink viscosity of the oil-based ballpoint pen ink composition is set to a low level of 300 mPa·s or less, as in the present invention, it is preferable to use a dye, because if a pigment is used, the effect of pigment dispersibility must be taken into consideration.

[0039] Examples of dyes include oil-soluble dyes, acid dyes, basic dyes, metal-containing dyes, nigrosine dyes, and various salt-forming dyes thereof, such as salt-forming dyes formed from an acid dye and a basic dye, salt-forming dyes formed from an organic acid and a basic dye, and salt-forming dyes formed from an acid dye and an organic amine. These dyes may be used alone or in combination of two or more.

[0040] Among these, in consideration of obtaining a dark handwriting, it is preferable to select from metal-containing dyes, nigrosine dyes, and salt-forming dyes.Furthermore, in consideration of the influence on the environment and safety, it is preferable to select from nigrosine dyes and salt-forming dyes that do not contain metals such as chromium and copper, and in consideration of obtaining a darker handwriting, nigrosine dyes are preferred.

[0041] Specific examples of 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, and BASE OF BASIC DYES MVB-3 (manufactured by Orient Chemical Industry Co., Ltd.), Aizenspiron Black GMH-Special, and Aizenspiron 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 Violet 510, SBN Yellow 530, SRC-BH (manufactured by Hodogaya Chemical Co., Ltd.), and the like.

[0042] Furthermore, examples of pigments include inorganic, organic, and processed pigments, and specific examples 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.

[0043] The colorant content is preferably 3.0% by mass or more and 30.0% 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 3.0% by mass, it tends to be difficult to obtain thick handwriting, and if it exceeds 30.0% by mass, it tends to affect the solubility in the ink. Taking these tendencies into consideration, the colorant content is preferably 5.0% by mass or more and 25.0% by mass or less, and even more preferably 5.0% by mass or more and 20.0% by mass or less.

[0044] (resin) The ink composition for the oil-based ballpoint pen of the present invention contains an ink viscosity modifier and a resin to improve adhesion (writing performance) to non-permeable surfaces. Examples of resins include ketone resins, amide resins, rosin-modified resins, rosin-modified phenolic resins, and other rosin resins, terpene-phenolic resins, alkylphenolic resins, polyvinyl butyral 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, and α- and β-pinene-phenol polycondensation resins. These resins may be used alone or in combination.

[0045] Among these resins, in consideration of the adhesion (writing properties) of the ink to the non-permeable surface and the suppression of ink leakage, at least one selected from terpene phenol resin, rosin resin, styrene-maleic acid resin, styrene-acrylic resin, and acrylic resin is preferred. From these considerations, the resin contained in the ink composition for an oil-based ballpoint pen is preferably terpene phenol resin or styrene-acrylic resin.

[0046] For terpene phenolic resins, considering the adhesion (writing ability) of the ink to non-permeable surfaces and the dissolution stability in the ink, the hydroxyl value of the terpene phenolic resin is preferably 300 mgKOH / g or less. More specifically, the hydroxyl value is preferably 30 mgKOH / g or more and 300 mgKOH / g or less, more preferably 80 mgKOH / g or more and 250 mgKOH / g or less, more preferably 100 mgKOH / g or more and 200 mgKOH / g or less, and more preferably 100 mgKOH / g or more and 170 mgKOH / g or less. Here, "hydroxyl value" refers to the number of milligrams (mg) of potassium hydroxide equivalent to the hydroxyl groups in 1 g of sample.

[0047] The softening point of the terpene phenol resin is preferably 100° C. or higher and 160° C. or lower, taking into consideration the adhesion of the ink to the non-penetrating surface and the dissolution stability in the ink. From further consideration, the softening point is preferably 110° C. or higher and 150° C. or lower. Here, the softening point of the terpene phenol resin (C) is a value measured in accordance with JIS K2207.

[0048] Furthermore, for styrene-maleic acid resin, styrene-acrylic resin, and acrylic resin, the acid value is preferably 300 mgKOH / g or more, taking into consideration the adhesion of the ink to non-permeable surfaces, the dissolution stability in the ink, and the drying properties of the ink. From further considerations, the acid value is preferably 50 mgKOH / g or more and 300 mgKOH / g or less, and more preferably 100 mgKOH / g or more and 250 mgKOH / g or less.

[0049] Furthermore, for styrene-maleic acid resin, styrene-acrylic resin, and acrylic resin, in consideration of the adhesion of the ink to the non-permeable surface and the dissolution stability in the ink, the mass average molecular weight is preferably 30,000 or less. In particular, the mass average molecular weight of these resins is preferably 20,000 or less, and in consideration of the adhesion of the ink to the non-permeable surface, it is preferably 5,000 or more, and even more preferably 8,000 or more.

[0050] The acid value of a resin means the number of milligrams of potassium hydroxide required to neutralize 1 g of resin. The mass average molecular weight can be determined by GPC.

[0051] Specific examples of these resins include the YS Polystar U, T, G, S, N, K, and TH series (manufactured by Yasuhara Chemical Co., Ltd.) and the Tamanol series (manufactured by Arakawa Chemical Industries, Ltd.).

[0052] If the total resin content is less than 3% by mass relative to the total amount of the ink composition for oil-based ballpoint pens, it is difficult to obtain sufficient effects in terms of adhesion (writing performance) to non-permeable surfaces and suppression of ink leakage. Furthermore, if the total resin content relative to the total amount of the ink composition for oil-based ballpoint pens exceeds 40% by mass, the solubility in the ink tends to be poor, the ink viscosity becomes too high, and ink consumption tends to decrease and writing feel and writing performance are easily affected. Therefore, the total resin content relative to the total amount of the ink composition for oil-based ballpoint pens is preferably 3% to 40% by mass, and more particularly, 5% to 30% by mass is preferred, and 10% to 25% by mass is preferred.

[0053] In addition, the ink composition for the oil-based ballpoint pen of the present invention may contain, in addition to the resins described above, a stringiness imparting agent as appropriate. In particular, the incorporation of a polyvinylpyrrolidone resin enhances the ink's binding properties and facilitates the suppression of excess ink at the tip end. For this reason, the ink composition for the oil-based ballpoint pen preferably contains a polyvinylpyrrolidone resin. If the content of the polyvinylpyrrolidone resin is less than 0.01% by mass relative to the total ink composition for the oil-based ballpoint pen, it is difficult to suppress the generation of excess ink. Furthermore, if the content exceeds 3.0% by mass, the solubility in the ink tends to be poor. For this reason, the content of the polyvinylpyrrolidone resin relative to the total ink composition for the oil-based ballpoint pen is preferably 0.01% by mass or more and 3.0% by mass or less. Considering the above reasons, this content is preferably 0.1% by mass or more and 2.0% by mass or less. Specific examples of polyvinylpyrrolidone resins include the PVP series (manufactured by ISP Japan Co., Ltd.). These may be used alone or in combination of two or more.

[0054] (surfactant) The ink composition for the oil-based ballpoint pen of the present invention contains a surfactant, which improves wettability to non-permeable surfaces, enables writing on non-permeable surfaces as well as paper, improves lubricity, and improves writing performance when the tip end dries out while left in the air.

[0055] The surfactant is preferably one or more selected from phosphate ester surfactants, silicone surfactants, surfactants having an acetylene bond, fluorine surfactants, fatty acids, and fatty acid esters.

[0056] Among surfactants, it is preferable to use phosphate ester surfactants and silicone surfactants, considering that improving the wettability to non-permeable surfaces suppresses handwriting repellency, enables good writing on non-permeable surfaces, and improves writing performance. Furthermore, phosphate ester surfactants are preferable because they have the effect of easily improving the writing feel and writing performance. Furthermore, it is preferable to use a combination of phosphate ester surfactants and silicone surfactants as surfactants.

[0057] Specific examples of phosphate ester 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 of a polyoxyethylene alkyl ether or a polyoxyethylene alkylaryl ether, 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.

[0058] 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 Plasurf 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.).

[0059] Among the phosphate ester surfactants, those with an alkoxyethyl group (C n H 2n+1 O-C2H4O) or alkoxy groups (C m H 2m+1O), phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers, and phosphoric acid diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkylaryl ethers.

[0060] Furthermore, among the phosphate ester surfactants, those with an alkoxyethyl group (C n H 2n+1 O-C2H4O) or alkoxy groups (C m H 2m+1 It is preferable to use a phosphate ester surfactant having an alkoxyl group (C m H 2m+1 It is preferable to use a phosphate ester surfactant having the formula O).

[0061] The phosphate ester surfactants have 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 the ink of formula (I) has an appropriate length, it is easy to maintain good writing performance on non-permeable surfaces, so the carbon chain (n, m) of the terminal alkyl group is preferably 4 or more and 20 or less, and more particularly, the carbon chain (n, m) is preferably 8 or more and 18 or less, and the carbon chain (n, m) is preferably 12 or more and 18 or less.

[0062] Specific examples of the silicone surfactant include dimethyl silicone, methylphenyl silicone, polyether-modified silicone, higher fatty acid ester-modified silicone, etc. Among the silicone surfactants, polyether-modified silicone is preferably used in view of improving wettability to non-penetrable surfaces.

[0063] Specific examples of silicone surfactants include the BYK series (manufactured by BYK Japan K.K.), the L series, the FZ series (manufactured by Dow Corning Toray Co., Ltd.), the KF series (manufactured by Shin-Etsu Chemical Co., Ltd.), the Silface series (manufactured by Nissin Chemical Industry Co., Ltd.), and the Disparlon series (manufactured by Kusumoto Chemical Co., Ltd.).

[0064] Regarding the HLB value of the surfactant, in consideration of improving wettability to non-permeable surfaces, writing performance, and writing feel, the HLB value is preferably 12 or less, and even more preferably 9 or less. Furthermore, in consideration of ink stability over time, the HLB value is preferably 3 or more, and even more preferably 5 or more.

[0065] The HLB value used in the present invention can be determined by the Griffin method, Kawakami method, or the like.

[0066] The surfactant content is preferably 0.1% by mass or more and 5.0% by mass or less relative to 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 tends to be difficult to obtain the desired wettability and lubricity on non-penetrable surfaces, and if it exceeds 5.0% by mass, the ink tends to become unstable over time. Taking these trends into consideration, the surfactant content is preferably 0.3% by mass or more and 4.0% by mass or less, and even more preferably 0.5% by mass or more and 3.0% by mass or less relative to the total amount of the ink composition for oil-based ballpoint pens.

[0067] (silica) The ink composition for the oil-based ballpoint pen of the present invention preferably further contains silica.

[0068] By further containing silica, the ink composition for an oil-based ballpoint pen of the present invention can have an ink viscosity of 20°C at a shear rate of 200 sec -1 In this case, even if the viscosity is set to 300 mPa s or less and the ink consumption per 100 m of writing distance of the oil-based ballpoint pen is 80 mg or more, it is possible to obtain the effect of suppressing ink leakage from the gap between the ball and the tip end (suppressing weighted ink leakage). Furthermore, by further containing silica in the ink composition for an oil-based ballpoint pen, it is possible to reduce the rotational resistance of the ball in the ballpoint pen tip, and to maintain an even better writing feel.

[0069] The silica contained in the ink composition for oil-based ballpoint pens of the present invention may be either hydrophilic or hydrophobic silica, but in consideration of the effect of suppressing ink leakage, it is preferable to use hydrophobic silica.

[0070] Furthermore, when considering stability over time in the ink composition for an oil-based ballpoint pen, it is preferable to use silica treated with a surface treatment agent. Regarding the surface treatment, it is preferable to treat the silica so that it has an alkylsilyl, alkylsiloxane, aminoalkylsilyl, methacrylsilyl, or the like as a surface modification group. When considering further suppression of ink leakage, it is preferable to treat the silica so that it has an alkylsilyl as a surface modification group, and when considering further suppression, it is preferable to treat the silica so that it has a dimethylsilyl.

[0071] Furthermore, the smaller the average primary particle size of the silica, the more easily it forms a weakly aggregated structure and the easier it is to suppress ink leakage. Therefore, the average primary particle size of silica is preferably 50 nm or less, more preferably 30 nm or less, and even more preferably 20 nm or less. Furthermore, if the average primary particle size of silica is less than 5 nm, it is too small and is likely to affect the ink leakage suppression effect. Therefore, the average primary particle size of silica is preferably 5 nm or more, and even more preferably 10 nm or more. The average primary particle size (D50) is determined by averaging values ​​measured with an electron microscope at n = 100.

[0072] The specific surface area of ​​the silica is set at 30m², taking into consideration the ink leakage prevention effect. 2 / g or more 300m 2 The specific surface area of ​​silica is preferably 50 m / g or less, taking into consideration the ink leakage suppression and ink stability over time. 2 / g or more 250m 2 / g or less is more preferable, and 100m 2 / g or more 220m 2 / g or less is more preferable.

[0073] Here, the "specific surface area" means the surface area per 1 g. The "specific surface area" can be measured by the BET method.

[0074] Furthermore, the content of the silica is preferably 0.01% by mass or more and 3% by mass or less based on the total amount of the ink composition for oil-based ballpoint pens. This is because if the content of silica is less than 0.01% by mass, it is difficult to suppress ink leakage, and if it exceeds 3% by mass, it is likely to affect the stability of the ink over time. In consideration of further suppression of ink leakage and stability of the ink over time, the content of silica is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.01% by mass or more and 0.5% by mass or less.

[0075] As for the silica, examples of hydrophobic silica and hydrophilic silica include the Aerosil series (manufactured by Nippon Aerosil Co., Ltd.).

[0076] (organic amine) In consideration of the stability of the ink components in the ink, the ink composition for the oil-based ballpoint pen of the present invention preferably further contains an organic amine. Examples of organic amines include amines containing ethylene oxide, such as oxyethylene alkylamines and polyoxyethylene alkylamines; alkyl amines, such as laurylamine and stearylamine; and aliphatic amines, such as dimethyl alkyl amines, distearylamine, dimethyl laurylamine, dimethyl stearylamine, and dimethyl octylamine. Among these, in consideration of stability in the ink, amines containing ethylene oxide and dimethyl alkyl amines are preferred. In particular, when the ink composition for the oil-based ballpoint pen contains a phosphate ester surfactant, the inclusion of an organic amine is preferred because it stabilizes the ink by neutralization, making it easier to obtain the effects of the phosphate ester surfactant.

[0077] Furthermore, the reactivity of the organic amine with other components in the ink is strongest with primary amines, followed by secondary amines and tertiary amines, which show decreasing reactivity. Therefore, in consideration of the ink's stability over time, it is preferable to use secondary amines or tertiary amines as the organic amine. These may be used alone or in combination of two or more.

[0078] Furthermore, in consideration of stability with the ink components, the total amine value of the organic amine is preferably 70 mgKOH / g or more and 300 mgKOH / g or less. This is because if it exceeds 300 mgKOH / g, it is highly reactive and easily reacts with the above components, which tends to deteriorate the ink stability over time. On the other hand, if the total amine value is less than 70 mgKOH / g, the ink stability over time is likely to be affected. In consideration of stability with the above components, the total amine value is preferably 100 mgKOH / g or more and 300 mgKOH / g or less. In consideration of stability, the total amine value is preferably 150 mgKOH / g or more and 300 mgKOH / g or less, and more preferably 180 mgKOH / g or more and 280 mgKOH / g or less.

[0079] 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.

[0080] Considering the stability with the ink components, the content of the organic amine is preferably 0.1% by mass or more and 10.0% by mass or less relative to the total amount of the ink composition for oil-based ballpoint pens. Furthermore, considering the neutralization of surfactants such as phosphate ester surfactants, the content of the organic amine is preferably 0.1% by mass or more and 5.0% by mass or less, and more preferably 0.3% by mass or more and 3.0% by mass or less relative to the total amount of the ink composition for oil-based ballpoint pens.

[0081] Additionally, the ink composition for the oil-based ballpoint pen of the present invention may contain, as appropriate, a colorant stabilizer, a plasticizer, a chelating agent, an antifoaming agent, water, a pseudoplasticity imparting agent, etc. These may be used alone or in combination of two or more kinds.

[0082] (ballpoint pen) Next, a ballpoint pen using the oil-based ballpoint pen ink composition of the present invention will be described.

[0083] 1 is a cross-sectional view of an example of a ballpoint pen 100 according to this embodiment. The ballpoint pen 100 is an example of an oil-based ballpoint pen.

[0084] The ballpoint pen 100 has a ballpoint pen refill 1. The ballpoint pen refill 1 is a replacement lead for the ballpoint pen 100. The ballpoint pen refill 1 has an ink reservoir 2. The ink reservoir 2 is cylindrical and elongated in an extension direction X. The extension direction X is a direction along a straight line passing through the center of a cross section of the cylindrical ink reservoir 2. In other words, the extension direction X is a direction along the central axis of the cylindrical ink reservoir 2.

[0085] An ink composition 10 for an oil-based ballpoint pen is contained inside the ink reservoir 2. The ink composition 10 for an oil-based ballpoint pen is the ink composition for an oil-based ballpoint pen of the present invention described above. As described above, in this embodiment, the ink composition for an oil-based ballpoint pen is referred to as an ink composition for an oil-based ballpoint pen, an ink composition, or an ink.

[0086] A ballpoint pen tip 4 is provided at one end of the ink reservoir 2 in the extension direction X. The ballpoint pen tip 4 is a member that rotatably holds the ball 3. That is, the ballpoint pen tip 4 holds the ball 3 at the tip end, which is one end of the ink reservoir 2 in the extension direction X.

[0087] 2 is an enlarged cross-sectional view of an example of the ballpoint pen tip 4. The ballpoint pen tip 4 includes a tip body 4A. The tip body 4A is provided with a coil spring 5, an ink flow hole 6, an ink flow groove 7, a ball seat 8, and a ball holding chamber 9.

[0088] The ink flow hole 6 is a hole that penetrates in the stretching direction X and through which ink flows. The ink is an ink composition 10 for an oil-based ballpoint pen. The ink flow groove 7 is a groove that extends radially from the ink flow hole 6. The ball holding chamber 9 is provided at the end of the ink flow hole 6 and has a ball seat 8 on which the ball 3 is placed. A coil spring 5 is provided in the ball seat 8, which presses the ball 3 placed on the ball seat 8 toward the inner wall of the tip end T. When the ball 3 is placed on the ball seat 8, the ball 3 is rotatably held so that a portion of it protrudes from the tip end T.

[0089] When writing is performed using a ballpoint pen 100 having a ballpoint pen refill 1, the ink, which is an oil-based ballpoint pen ink composition 10 that flows out of the ink reservoir 2, is supplied from the ink flow hole 6 through the ink flow groove 7 to the ball 3 held in the ball holding chamber 9. By supplying the ink to the ball 3, writing with the ink is performed on paper or the like.

[0090] The ink composition 10 for an oil-based ballpoint pen contained in the ink reservoir 2 is the ink composition for an oil-based ballpoint pen of the present invention described above.

[0091] The amount of movement of the ball 3 in the extension direction X of the ballpoint pen tip 4 of the ballpoint pen 100 of the present invention is preferably 10 μm or more and 50 μm or less. The amount of movement of the ball 3 in the extension direction X means the distance that the ball 3 can move in the extension direction X relative to the tip body 4A. The amount of movement is sometimes referred to as clearance.

[0092] If the amount of movement of the ball 3 in the stretching direction X is less than 10 μm, it becomes difficult to ensure the desired ink consumption, and it becomes difficult to obtain thick handwriting, writing ability on non-permeable surfaces, and a smooth writing feel. On the other hand, if the amount of movement of the ball 3 in the stretching direction X exceeds 50 μm, it becomes more likely to affect ink leakage prevention, blobbing, bleeding, handwriting drying speed, and bleed-through. From further consideration, the amount of movement is preferably 20 μm or more and 50 μm or less, and more preferably 25 μm or more and 45 μm or less.

[0093] In the present invention, the amount of movement of the ball 3 of the ballpoint pen tip 4 in the extension direction X represents the amount of movement of the ball 3 of the ballpoint pen tip 4 of the ballpoint pen 100 in the initial state before starting writing.

[0094] As mentioned above, there is no limitation on the diameter of the ball 3. As mentioned above, the diameter of the ball 3 is preferably about 0.1 mm or more and 2.0 mm or less, and particularly preferably in the range of 0.3 mm or more and 1.6 mm or less.

[0095] As described above, the ratio of ink consumption A (mg) per writing distance of 100 mm to ball diameter B (mm), which is the diameter (mm) of the ball 3, of the ballpoint pen 100, which is the oil-based ballpoint pen of the present invention (ink consumption / ball diameter=A / B) is 100 ​

[0096] The arithmetic mean roughness (Ra) of the ball 3 surface of the ballpoint pen tip 4 used in the present invention is preferably 0.1 nm or more and 12 nm or less. This is because if the arithmetic mean roughness (Ra) is less than 0.1 nm, it is difficult for ink to adhere sufficiently to the ball 3 surface, making it difficult to obtain thick handwriting during writing and prone to line skipping and smearing in the handwriting. If the arithmetic mean roughness (Ra) exceeds 12 nm, the ball 3 surface becomes too rough, increasing the rotational resistance of the ball 3 and ball seat 8, which tends to deteriorate the writing feel and further affect writing performance, such as smearing, line skipping, and line unevenness in the handwriting. Furthermore, if the arithmetic mean roughness (Ra) is 0.1 nm or more and 10 nm or less, it is easy to maintain the ability to write on non-permeable surfaces. More preferably, the arithmetic mean roughness (Ra) is 0.1 nm or more and 8 nm or less. The arithmetic mean roughness (Ra) of the ball 3 can be measured using a Seiko Epson model SPI3800N. The arithmetic mean roughness (Ra) is calculated by extracting a reference length from the roughness curve measured by this surface roughness measuring instrument in the direction of the mean line, and averaging the absolute values ​​of the deviations from the mean line of this extracted portion to the measurement curve.

[0097] The material used for ball 3 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.

[0098] The material of the ballpoint pen tip 4 may be metal, such as stainless steel, nickel silver, brass, aluminum bronze, or aluminum, or resin, such as polycarbonate, polyacetal, or ABS. Considering the wear of the ball seat 8, stability over time, and cost, it is preferable that the ballpoint pen tip 4 have a tip body 4A made of stainless steel. [Example]

[0099] 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.

[0100] Example 1 The ink composition for an oil-based ballpoint pen in Example 1 used a dye as a colorant, a lower alcohol and ethylene glycol monophenyl ether as organic solvents, a phosphate ester surfactant having an alkoxyl group as a surfactant, a polyether-modified silicone, a polyoxyethylene alkylamine as an organic amine, and a terpene phenol resin. A predetermined amount of these was weighed out, heated to 60°C, and then completely dissolved using a Disper stirrer to obtain an ink composition for an oil-based ballpoint pen.

[0101] The specific blending amounts are as follows: The viscosity was measured using a Brookfield Viscometer RVDVII+Pro CP-42 spindle at a shear rate of 200 sec at 20°C. -1 The ink viscosity (mPa·s) of the oil-based ballpoint pen ink composition of Example 1 was measured.

[0102] Example 1 (ink formulation) Colorant (salt dye) 10.0% by mass Organic solvent (lower alcohol: a mixture of ethanol (boiling point 79°C) and isopropyl alcohol (boiling point 82°C)) 52.7% by mass Organic solvent (ethylene glycol monophenyl ether, boiling point 245°C) 3.0% by mass Silica 0% by mass Phosphate ester surfactants (alkoxyl group (C m H 2m+1 O): Phosphate ester surfactant having m=18) 1.0% by mass Silicone surfactant (polyether-modified silicone, HLB value: 6) 0.3% by mass Organic amine (polyoxyethylene alkylamine) 2.0% by mass Terpene phenol resin (hydroxyl value: 160mgKOH / g) 31.0% by mass

[0103] Tables 1 to 5 show the measurement and evaluation results.

[0104] Examples 2 to 33 As shown in Tables 1 to 5, except for changing the ink components and tip specifications, ink compositions for oil-based ballpoint pens of Examples 2 to 33 were obtained in the same manner as in Example 1. Tables 1 to 5 show the measurement and evaluation results.

[0105] Comparative Examples 1 to 6 As shown in Tables 1 to 5, ink compositions for oil-based ballpoint pens of Comparative Examples 1 to 6 were obtained in the same manner as in Example 1, except that the ink components and tip specifications were changed. Tables 1 to 5 show the measurement and evaluation results.

[0106] [Table 1]

[0107] [Table 2]

[0108] [Table 3]

[0109] [Table 4]

[0110] [Table 5]

[0111] Testing and Evaluation Tests and evaluations were carried out using the ballpoint pen 100 described with reference to Figures 1 and 2. Specifically, the ink compositions (1.0 g) for oil-based ballpoint pens prepared in Examples 1 to 33 and Comparative Examples 1 to 6 were placed in an ink reservoir 2 (polypropylene). Then, a ballpoint pen tip 4 (movement amount in the extension direction X: 35 µm, arithmetic mean roughness (Ra) of the ball 3 surface: 1 nm) rotatably holding a ball 3 having a ball diameter of φ0.38 mm was attached to the ballpoint pen refill 1, and the ballpoint pen refill 1 was filled into the ink reservoir 2. Through these processes, the ballpoint pen 100, which is an oil-based ballpoint pen, and a comparative ballpoint pen were prepared.

[0112] The ballpoint pen tip 4 used had a coil spring 5 that pressed the ball 3 against the inner wall of the tip tip T (see Figure 2). The material of the ball 3 was a cemented carbide ball (containing cobalt as a binder) whose main component was tungsten carbide. The ball diameter, which was the diameter of the ball 3, and the arithmetic mean roughness (Ra) of the surface of the ball 3 were as shown in Tables 1 to 5.

[0113] The following test was conducted using JIS P3201 writing paper.

[0114] The ink consumption (mg) per 100 m of writing distance was determined by the spiral writing test described above using the oil-based ballpoint pens of Examples 1 to 33 and the comparative ballpoint pen. The results obtained are shown in Tables 1 to 5. Tables 1 to 5 also show the A / B values, where A (mg) is the ink consumption per 100 m of writing distance and B (mm) is the diameter of the ball 3.

[0115] Furthermore, when the movement distance of the ball 3 in the extension direction X of the ball point pens 100, which are oil-based ball point pens of Examples 1 to 33, and the comparative ball point pens of Comparative Examples 1 to 6, was measured, the results shown in the table were obtained. In the table, "ball movement distance" is the movement distance of the ball 3 in the extension direction X.

[0116] The following evaluations were carried out on the ballpoint pens 100, which are oil-based ballpoint pens of Examples 1 to 33, and the comparative ballpoint pens of Comparative Examples 1 to 6. As for the writing test paper, JIS P3201 writing paper was used as above.

[0117] Thickness of handwriting: Handwriting written by hand on a writing test paper was visually evaluated. · Thick, clear handwriting ···◎ ·Thick handwriting···○ ·Handwriting that is thick enough to cause no problems in practical use ···△ ·Light handwriting ···×

[0118] Test 1 for writing on non-permeable surface: Handwritten marks were written on a polyethylene terephthalate (PET) sheet and evaluated visually. · The writing lines are in good condition with no repelling or fading of color ···◎ · The writing lines have some repellency or fading, but are still usable ···○ · The written lines are repellent or faded, which is a concern for practical use ···×

[0119] Test 2 for writing on non-permeable surfaces: Handwritten marks were written on a polyethylene terephthalate (PET) sheet and evaluated visually. ·Good handwriting smudge prevention, no blobbing, and good drying properties···◎ There is some smearing, bleeding or drying of handwriting, but no practical problems. ···○ -Handwriting is smudged, blurred, or dry, which is a concern for practical use. ···×

[0120] Writing performance test: After handwriting on a writing test paper, the tip was left exposed for 24 hours in an environment of 20°C and 65% RH. After that, writing was performed under the following writing conditions in a running test, and the length of the smeared handwriting at the beginning of writing was measured.

[0121] <Writing conditions> A straight line was written on a running test machine under the following conditions: writing load 200 gf, writing angle 70°, writing speed 4 m / min, and evaluation was performed. The length of the smudged handwriting is 1mm or more but less than 5mm. The length of the smudged handwriting is 5mm or more but less than 15mm. The length of the smudged handwriting is 15mm or more but less than 30mm. The length of the blurred handwriting is 30mm or more. ×

[0122] Writing feel: Evaluation was carried out by a sensory test using handwriting. Very smooth ◎ ·Smooth ···○ ·Slightly less smooth ···△ Heavy items ×

[0123] Furthermore, a pressurized ink leakage suppression test was carried out on the ballpoint pens 100 of Examples 26 to 33, which were oil-based ballpoint pens using silica-containing ink compositions for oil-based ballpoint pens.

[0124] Weighted ink leakage suppression test: A 40 g weight was attached to the ballpoint pen 100, and the ballpoint pen tip 4 was protruded and pointed downward. Then, the ball 3 of the ballpoint pen tip 4 was kept in contact with the bottom of a ballpoint pen display case, and the ballpoint pen was left for one day in an environment of 20°C and 65% RH, and ink leakage from the tip tip T was confirmed. ·Almost no ink leakage from tip tip T is observed···◎ ·Ink leakage from the tip T is practically not a concern ···○ · Ink leakage from the tip tip T is a practical problem ···×

[0125] Examples 1 to 33 showed good performance in all of the following: thickness of handwriting, test 1 and test 2 of writing on impermeable surfaces, writing performance test, writing feel, and weighted ink leakage suppression test.

[0126] Furthermore, in terms of the darkness of the handwriting, when Examples 13 to 16 (similar blends) were compared, Example 14, which contained nigrosine dye as a colorant, produced the darkest handwriting.

[0127] Furthermore, the pigment dispersibility of the pigment ink of Example 16 was practically satisfactory.

[0128] Comparative Example 1 did not use an organic solvent with a boiling point of 140° C. or less, and therefore the drying properties of the writing were poor, and the evaluation results of the writing test 1 and writing test 2 on the non-penetrable surface were inferior to those of the Examples.

[0129] In Comparative Example 2, the ink viscosity was high, so that repelling and smearing occurred in the writing test 1 and writing test 2 on the non-permeable surface, and the writing performance test was inferior to that of the Examples.

[0130] In Comparative Example 3, A / B<100, the thickness of the handwriting was insufficient, repelling and smearing occurred in the writing test 1 and writing test 2, and the writing performance test was inferior to that of the Examples.

[0131] Since Comparative Example 4 had A / B>600, the ink dried poorly compared to the Examples in the writing test 2 on a non-permeable surface, and the ink smearing was poor compared to the Examples.

[0132] In Comparative Examples 5 and 6, the ink consumption per 100 m of writing distance of the oil-based ballpoint pen was low, so the writing was not thick enough compared to the Examples, and repelling and smearing occurred in Writing Test 1 and Writing Test 2.

[0133] To improve writing performance (handwriting smearing) and ink leakage prevention, the ballpoint pen tip 4 is preferably equipped with a valve mechanism. The valve mechanism presses the ball 3, which is rotatably held at the tip end T, against the inner wall of the tip end edge by a coil spring 5 directly or via a pressing body, and the pressing force during writing creates a gap between the inner wall of the tip end edge and the ball 3, allowing ink to flow out. It is preferable that the valve mechanism closes even the minute gap at the tip end T when not in use.

[0134] This is particularly effective when using retractable oil-based ballpoint pens (retractable ballpoint pens) such as knock-type oil-based ballpoint pens and twist-type oil-based ballpoint pens, as writing performance and ink leakage prevention performance are among the most important performance characteristics.

[0135] For convenience, the present embodiment shows an example of an oil-based ballpoint pen, in which a ballpoint pen 100 having a ballpoint pen refill 1 in which an ink composition 10 for an oil-based ballpoint pen is directly accommodated in an ink reservoir 2, as an oil-based ballpoint pen. However, the oil-based ballpoint pen of the present invention may also be a direct-fill type ballpoint pen or an oil-based ballpoint pen in which the barrel is the ink reservoir 2 and the ink composition 10 for an oil-based ballpoint pen is directly accommodated in the barrel. Alternatively, the ballpoint pen may have a structure in which the ink reservoir 2 containing the ink composition 10 for an oil-based ballpoint pen (ballpoint pen refill 1) is used as is as a ballpoint pen.

[0136] Furthermore, for convenience, the present embodiment illustrates the ballpoint pen tip 4 formed by cutting a wire material, but the ballpoint pen tip 4 may be formed by pressing a pipe material. [Industrial Applicability]

[0137] The present invention can be used as an oil-based ballpoint pen, and more specifically, can be widely used as an oil-based ballpoint pen such as a cap type or a retractable type. [Explanation of symbols]

[0138] 100 ballpoint pens 10. Ink composition for oil-based ballpoint pens 1 ballpoint pen refill 2 Ink reservoir 3 Ball 4 Ballpoint pen tips

Claims

1. An oil-based ballpoint pen having a ballpoint pen tip at the tip of an ink reservoir, and an ink composition for an oil-based ballpoint pen containing a colorant, an organic solvent having a boiling point of 140°C or less, a resin, and a surfactant, the ink composition having an ink viscosity of 20°C at a shear rate of 200 sec －１ the viscosity of the oil-based ballpoint pen is 300 mPa s or less, the ink consumption per 100 m of writing distance of the oil-based ballpoint pen is 80 mg or more, and the ratio of the ink consumption A (mg) per 100 m of writing distance to the ball diameter B (mm) is 100 < A / B < 600, the resin is any one of a terpene phenol resin, a styrene-maleic acid resin, a styrene-acrylic resin, and an acrylic resin; The hydroxyl value of the terpene phenol resin is 100 mgKOH / g or more and 170 mgKOH / g or less, the styrene-maleic acid resin and the styrene-acrylic resin have acid values ​​of 100 mgKOH / g or more and 250 mgKOH / g or less; The acid value of the acrylic resin is 80 mg KOH / g. An oil-based ballpoint pen characterized by:

2. The surfactant is one or more selected from the group consisting of a phosphate ester surfactant, a silicone surfactant, a surfactant having an acetylene bond, a fluorine surfactant, a fatty acid, and a fatty acid ester. The oil-based ballpoint pen according to claim 1.

3. The surfactant has an HLB value of 12 or less. The oil-based ballpoint pen according to claim 1 or 2.

4. The ink composition for an oil-based ballpoint pen further contains an organic solvent having a boiling point of 160°C or higher. The oil-based ballpoint pen according to claim 1.

5. The ink composition for an oil-based ballpoint pen is characterized in that it further contains silica. The oil-based ballpoint pen according to claim 1.

6. The specific surface area of ​​the silica is 30 m ２ / g or more 300m ２ / g or less The oil-based ballpoint pen according to claim 5.

7. The average temporary particle size of the silica is 5 nm or more and 50 nm or less. The oil-based ballpoint pen according to claim 5.

8. The amount of movement of the ball of the ballpoint pen tip in the extension direction of the ink reservoir is 10 μm or more and 50 μm or less. The oil-based ballpoint pen according to claim 1.

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