JP6286254B2 - Ink composition for oil-based ballpoint pen, oil-based ballpoint pen refill using the same, and oil-based ballpoint pen - Google Patents

Description

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

  Conventionally, in an oil-based ballpoint pen ink composition, if the tip of the tip is left in the air, the solvent in the ink evaporates and the colorant or resin is dried and solidified. There was a drawback that would occur.

  In order to improve the writing performance at the time of writing, it has been considered to use various solvents and additives. For example, as a main solvent containing a non-volatile organic solvent having a vapor pressure of 0.005 to 0.5 mmHg (20 ° C.), Japanese Patent Application Laid-Open No. 6-247093 “Oil Ballpoint Pen” has an average molecular weight of 200 to Japanese Patent Application Laid-Open No. 7-196971 “Ink composition for oil-based ballpoint pen” contains polyethylene glycol having a weight average molecular weight of 250,000 or more. No. 2002-3771 “Ink composition for oil-based ballpoint pen” contains at least decacademia nut oil fatty acid decaglyceryl and an alkyl group having 16 or more carbon atoms and a polyoxyethylene alkyl ether that is solid at room temperature. , JP 2008-88264 A "Oil-based ink composition for ballpoint pens" To "and the like, have been disclosed.

"Japanese Patent Laid-Open No. 6-247093" "Japanese Patent Laid-Open No. 7-196971" "JP 2002-3771 A" "Japanese Patent Laid-Open No. 2008-88264" "Japanese Patent Laid-Open No. 9-71745" "Japanese Patent Laid-Open No. 11-343444"

  However, in Patent Document 1, when a non-volatile organic solvent having a vapor pressure of 0.005 to 0.5 mmHg (20 ° C.) is contained as the organic solvent, there is an effect of preventing the ink from being completely dried. The dryness of the paper was poor, and it alone could not satisfy the writing performance.

  Moreover, in patent documents 2-3, when polyethylene glycol or polyvinylpyrrolidone having a specific molecular weight is contained as an additive, by forming a resin film on the tip of the tip, further drying of the tip of the tip is suppressed, Although it is possible to improve the dry-up resistance to some extent by suppressing the ink thickening in the chip, the resin film is hard, so writing at the time of dry-up will cause blurring and sufficient No dry-up performance was obtained.

Further, in Patent Document 4, although it is possible to improve the dry-up resistance to some extent by using decamacademia nut oil fatty acid decaglyceryl and polyoxyethylene alkyl ether in combination, a special surfactant is used. Depending on the choice of colorant, organic solvent, other surfactants, etc., it will affect the ink stability over time, and if it does not match the dye and other surfactants, precipitates will be generated. Problems that cause poor writing tend to occur.

  As a technique for specifying a colorant, in Patent Document 5, a triarylmethane basic dye and an azo yellow acid dye salt-forming dye, an aliphatic alcohol, or a urethane-modified ketone formaldehyde resin is used as a colorant. In this case, the dissolution stability of the salt-forming dye and the aliphatic alcohol is inferior, and the ink aging stability tends to be affected. In Patent Document 6, C.I. I. Basic Blue 55 and C.I. I. Because of its structure, Solvent Blue 44 has poor stability and poor solubility in solvents, and particularly poor solubility in solvents such as glycols, glycol ethers, and alcohols that do not have an aromatic ring. Problems that cause defects are likely to occur.

  As in Patent Documents 4 to 6, the selection of ink components such as a colorant, an organic solvent, a surfactant, and a resin also has compatibility with each component, and the stability with time with ink and the lubricant are determined by one component. This is a very important configuration.

  An object of the present invention is to provide an ink composition for oil-based ballpoint pens that is excellent in writing performance upon dry-up, ink aging stability, and writing quality.

In order to solve the above problems, the present invention
“1. At least a colorant, an organic solvent, a resin, a phosphate ester surfactant, and an organic amine, and the colorant is a salt-forming dye of an alkylbenzenesulfonic acid and a triarylmethane skeleton basic dye, Is a secondary amine and / or a tertiary amine, where X is the total amine value of the organic amine and Y is the acid value of the phosphate ester surfactant, 0.1 ≦ Y / X ≦ 1. An oil-based ballpoint pen ink composition, wherein the resin composition is 0 and the resin contains at least a polyvinyl butyral resin, and the content of the polyvinyl butyral resin is 70% or more based on the total resin content.
2. 2. The oil-based ballpoint pen ink composition according to item 1, wherein the organic solvent is an alcohol solvent.
3. Item 3. The ink composition for oil-based ballpoint pens according to Item 1 or 2 , wherein the total amine value of the secondary amine and / or tertiary amine is 70 to 300 (mg KOH / g).
4). The first to third items, wherein the resin contains at least a spinnability imparting resin, and the content of the spinnability imparting resin is 0.1 to 20% by mass with respect to the total resin content . Item 4. The ink composition for oil-based ballpoint pens according to any one of Items.
5). When the organic solvent contains at least an alcohol solvent and a glycol ether solvent, the content of the alcohol solvent is A, and the content of the glycol ether solvent is B, the relationship is 1 ≦ A / B ≦ 10. Item 5. The ink composition for oil-based ballpoint pens according to any one of Items 1 to 4 .
6. The ink composition for oil-based ballpoint pens according to any one of items 1 to 5 , wherein the ink viscosity at 20 ° C. and a shear rate of 500 sec ⁻¹ is 15000 to 35000 mPa · s.
7). A ballpoint pen tip holding a ball rotatably is attached to the tip of the ink containing cylinder directly or via a chip holder, and the ink containing cylinder is set forth in any one of items 1 to 6. An oil-based ballpoint pen refill containing the oil-based ballpoint pen refill, wherein the oil consumption of the oil-based ballpoint pen refill is 30 to 100 mg per 100 m.
8). 8. The oil-based ballpoint pen refill according to item 7 , wherein the movement amount of the ball in the axial direction is 5 to 20 μm.
9. 9. The oil-based ballpoint refill according to item 7 or 8, wherein the arithmetic average roughness of the surface of the ball is 0.1 to 15 nm.
10. An oil-based ballpoint pen comprising the oil-based ballpoint pen refill according to any one of Items 7 to 9 disposed in a shaft tube.
11. A retractable oil-based ballpoint pen in which the oil-based ballpoint pen refill according to any one of Items 7 to 9 is slidably disposed in a shaft cylinder, and the tip end portion of the ballpoint pen tip can be projected and retracted from the tip end portion of the shaft cylinder. An oil-based ballpoint pen characterized by being. "

  The present invention has a good writing performance at the time of dry-up that does not cause handwriting blurring by softening the solidification of the film to be formed when the tip tip is dried while the tip tip is left in the atmosphere. In addition, an ink composition for an oil-based ballpoint pen having good ink aging stability, improved lubricity, and good writing quality, and an oil-based ballpoint pen using the same can be provided.

It is a longitudinal cross-sectional view of the ball-point pen refill in this invention. FIG. 2 is an enlarged vertical cross-sectional view of a main part, partly omitted in FIG. 1.

  The feature of the present invention is at least a colorant, an organic solvent, a resin, a phosphate ester surfactant, an organic amine, and the colorant is a salt-forming dye of an alkylbenzenesulfonic acid and a triarylmethane basic dye, The organic amine is a secondary amine and / or a tertiary amine.

  It has been found that the phosphoric acid ester surfactant used in the present invention improves the writing performance at the time of dry-up without causing handwriting blurring even when the tip of the tip is dried. This is because the phosphate ester surfactant reduces the strength of the film formed when the tip of the tip is dried, and the effect of smoothing the rotation of the ball is obtained. It is estimated that the writing performance at the time of dry-up is improved without the occurrence of Furthermore, phosphate ester surfactants are preferably used because phosphate groups are easily adsorbed on the metal surface, maintain lubricity between the ball and the chip body, and improve writing quality.

  However, by including a phosphate ester surfactant in the oil-based ink, it is possible to improve the writing performance at the time of dry-up, but dissociates in the ink, and the ink component such as a colorant An organic amine is used for the purpose of neutralizing the phosphate ester surfactant because it may generate a precipitate upon reaction.

  As for the reactivity between the organic amine and other components in the ink, the primary amine is the strongest, and then the reactivity with the secondary amine and the tertiary amine is low. Since the primary amine easily reacts with an ink component such as a colorant and affects the ink aging stability, the selection of an ink component such as a colorant becomes strict, and therefore a secondary amine and / or a tertiary amine is used.

  As for the colorant used in the present invention, there are dyes and pigments. When a dye is used, it is easy to obtain a dark and fresh handwriting. On the other hand, in order to obtain pigment dispersion stability using a pigment, Since there are problems such as selection and cost problems, at least a dye is preferably used. Examples of the type of dye include salt-forming dyes of acid dyes and basic dyes, salt-forming dyes of organic acids and basic dyes, and salt-forming dyes of acid dyes and organic amines. Then, considering the stability with the phosphate ester surfactant and the organic amine, a salt-forming dye of an organic acid and a basic dye is used.

  Among them, it is important to select a salt-forming dye composed of a stable alkylbenzene sulfonic acid and a triarylmethane-based basic dye for a secondary amine and / or a tertiary amine. This is because the salt-forming dye of the alkylbenzene sulfonic acid and the triarylmethane-based basic dye has a strong ion binding force and is a stable salt-forming dye. On the other hand, if a colorant other than alkylbenzene sulfonic acid and triarylmethane basic dye is used, the colorant is not stable with respect to secondary amine and / or tertiary amine, and the colorant decomposes or precipitates are generated. It is because it ends up. Therefore, when a secondary amine and / or a tertiary amine is used, it is necessary to select a salt-forming dye of an alkylbenzene sulfonic acid and a triarylmethane type basic dye.

  Therefore, in order to improve the writing performance at the time of dry-up, the stability of the colorant (ink stability over time), and the writing quality, the phosphate ester surfactant, the secondary amine and / or the oil-based ink are used. Or, it is necessary to use a tertiary amine, a salt-forming dye of an alkylbenzene sulfonic acid and a triarylmethane basic dye in combination, but depending on the selection of the organic solvent, the original effect may be difficult to obtain. When the inventor diligently studied, it is preferable to use an alcohol solvent. This is because it is easy to maintain a stable neutralized state of a phosphate ester surfactant and a secondary amine and / or tertiary amine by using an alcohol solvent, and the alkylbenzene sulfonic acid and the triarylmethane base It also has the effect of dissolving and stabilizing salt-forming dyes with neutral dyes, making it easy to obtain long-term ink aging stability without deposits, and being stable for a long period of time and improving the writing performance during dry-up. is there.

  Regarding the organic amine used in the present invention, the total amine value of the organic amine is preferably in the range of 70 to 300 (mgKOH / g). When this exceeds 300, since the reactivity is strong, it easily reacts with other components in the ink, so that the ink aging stability tends to be poor. Further, if the total amine value is less than 70, neutralization with respect to the phosphate ester-based surfactant becomes insufficient, and the ink aging stability is likely to be affected. Adsorbability tends to be poor, and lubrication performance is difficult to obtain. If the ink aging stability and lubricity as described above are further considered, the range of 150 to 300 (mg KOH / g) is preferable, and the salt-forming dye of the alkylbenzene sulfonic acid and the triarylmethane type basic dye In consideration of stability, 200 to 300 (mgKOH / g) is preferable, and in consideration of 230 to 270 (mgKOH / g). The total amine value represents the total amount of primary, secondary, and tertiary amines, and is expressed in mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize 1 g of the sample.

  As for the secondary amine and tertiary amine, as oxyethylene alkylamine and polyoxyethylene alkylamine, specifically, Nimin L-201 (total amine value: 232 to 246, secondary amine), L-202 ( Total amine number: 192-212, tertiary amine), same L-207 (total amine number: 107-119, tertiary amine), same S-202 (total amine number: 152-166, tertiary amine), same S-204 (total amine value: 120-134, tertiary amine), S-210 (total amine value: 75-85, tertiary amine), DT-203 (total amine value: 227-247, tertiary) Amine), DT-208 (total amine number: 146 to 180, tertiary amine) (manufactured by NOF Corporation) and the like. Specific examples of the alkylamine and dimethylalkylamine include alkylamines such as Farmin D86 (total amine value: 110-119, secondary amine), DM2098 (total amine value: 254-265, tertiary amine), DM8680 ( Total amine number: 186-197, tertiary amine) (Kao Co., Ltd.), Nissan tertiary amine BB (total amine number: 243-263, tertiary amine), FB (total amine number: 230-250, 3 Grade amine) (manufactured by Nippon Oil & Fats Co., Ltd.). You may use these individually or in mixture of 2 or more types.

  The content of the organic amine is preferably 0.1 to 10.0% by mass and more preferably based on the total amount of the ink composition in consideration of the neutralization amount with the phosphate ester surfactant and the ink aging stability. Is 0.5-5.0 mass%.

  Examples of the phosphoric acid ester surfactant used in the present invention include polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphoric acid monoester, polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphoric acid diester, Examples include phosphoric acid triesters, alkyl phosphoric acid esters, alkyl ether phosphoric acid esters or derivatives thereof of oxyethylene alkyl ether or polyoxyethylene alkyl aryl ether, and the alkyl group of the phosphoric acid ester surfactant is styrenated. Phenol-based, nonylphenol-based, lauryl alcohol-based, tridecyl alcohol-based, octylphenol-based and the like can be mentioned. These phosphate ester surfactants may be used alone or in combination of two or more.

  Among them, the carbon number contained in the alkyl group is preferably 5 to 18 in view of lubricity, and the carbon number is preferably 10 to 18 in consideration of the writing performance during dry-up. More preferably, and most preferably, the carbon number is 12 to 18 in view of ink aging stability. If the alkyl group has too few carbon atoms, lubricity and writing performance tend to be insufficient, and if the carbon number is too large, ink aging stability tends to be affected. .

  Further, the content of the phosphate ester-based surfactant is more preferably 0.1 to 5.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, the desired writing performance and lubricity tend to be difficult to obtain, and if it exceeds 5.0% by mass, the ink aging tends to become unstable. Considering the tendency, 0.3 to 3.0% by mass is preferable, and more considering 0.5 to 3.0% by mass is most preferable.

Specific examples of the phosphate ester surfactant include Prisurf A217E (alkyl group: 14 carbon atoms, acid value: 45 to 58), A219B from the Prisurf series (Daiichi Kogyo Seiyaku Co., Ltd.). (Alkyl group: carbon number 12, acid value: 44 to 58), A215C (alkyl group: carbon number 12, acid value: 80 to 95), A208B (alkyl group: carbon number 12, acid value: 135 to 155) ), A208N (alkyl group: mixture of 12 and 13 carbon atoms, acid value: 160-185), phosphanol series (manufactured by Toho Chemical Co., Ltd.), phosphanol RB410 (alkyl group: carbon) No. 18, acid value: 80 to 90), RS-610 (alkyl group: carbon number 13, acid value: 75 to 90), RS-710 (alkyl group: carbon number 13, acid value: 55 to 75) Etc. It is. These phosphate ester surfactants may be used alone or in combination of two or more.
In addition, about an acid value, it shall represent with the mg number of potassium hydroxide required in order to neutralize the acidic component contained in 1g of samples.

  Further, when the total amine value of the organic amine is X and the acid value of the phosphate ester surfactant is Y, it is preferable that 0.1 ≦ Y / X ≦ 2.0. This is because if Y / X> 2.0 or Y / X <0.10, it is easy to promote precipitation over time due to the influence of ions of the ball material made of metal or the chip body, and it depends on the precipitate. This is because it tends to cause poor writing. Considering the above reasons, 0.1 ≦ Y / X ≦ 1.0 is preferable, and further considering 0.2 ≦ Y / X ≦ 0.8 is most preferable.

  Regarding salt-forming dyes of alkylbenzene sulfonic acid and triarylmethane basic dye used in the present invention, alkylbenzene sulfonic acid forms a lubricating film in which a phenyl sulfone group is easily adsorbed to a metal, and a ball and a chip body. It is used suitably because it has the effect of suppressing the metal contact between the two and the lubricity is improved and the writing quality is improved.

  The triarylmethane skeleton acidic dye is a basic dye having aromatic rings such as three phenyl groups and naphthyl groups on the same carbon. I. Basic Blue 1, 5, 7, 19, 26, C.I. I. Basic violet 1, 3, 4, 10, 15, C.I. I. Basic green 1, 4, and 7 are mentioned. Among them, considering that the ion binding force with alkylbenzene sulfonic acid is strong and a stable salt-forming dye is obtained, C.I. I. Basic blue 1, 5, 7, 19, 26 are preferred. Further, when considering stability to secondary amines and / or tertiary amines, C.I. I. Basic blue 7 and 26 are preferred. In particular, considering long-term ink aging stability and lubricity, C.I. I. Most preferred is a salt-forming dye using Basic Blue 7.

  The content of the salt-forming dye of the alkylbenzene sulfonic acid and the triarylmethane skeleton basic dye is preferably 5.0 to 30.0 mass% with respect to the total amount of the ink composition. If the amount is less than 5.0% by mass, a dark handwriting tends to be difficult to obtain. If the amount exceeds 30.0% by mass, the solubility in ink tends to be affected. Considering it, 7.0 to 25.0 mass% is preferable, and further considering it is 10.0 to 20.0 mass%.

  Examples of the resin used in the present invention include polyvinyl butyral resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, polyvinyl pyrrolidone resin, ketone resin, terpene resin, alkyd resin, phenoxy resin, and polyvinyl acetate resin. In order to improve ink drooping performance and writing quality, it is preferable to use at least polyvinyl butyral resin.

  However, some polyvinyl butyral resins may have poor compatibility depending on the choice of colorant and organic solvent, and may not be dissolved and stable in oil-based inks and may not be able to obtain their original effects. . This is because by using an aromatic alcohol solvent, the polyvinyl butyral resin and the salt-forming dyes of the azo skeleton acidic dye and triarylmethane skeleton basic dye are dissolved and stabilized for a long time without being separated from each other. Alcohol solvents are used because ink aging stability is obtained. Furthermore, since it is easy to improve lubricity by having an aromatic ring, it is preferable to use at least an aromatic alcohol solvent.

  Further, the polyvinyl butyral resin is obtained by reacting polyvinyl alcohol (PVA) with butyraldehyde (BA), and has a structure having a butyral group, an acetyl group, and a hydroxyl group. Although there is a technique suitably used as a pigment dispersant, the present invention has an effect of easily improving the ink drooping performance and writing quality.

  This is because polyvinyl butyral resin forms a resin film at the tip of the tip and covers the gap between the tip of the ball and the tip, thereby suppressing ink drooping. In addition, the ink is always elastic between the ball and the ball seat. This is because the layer is formed so that it is difficult to make direct contact, so that the writing quality can be easily improved.

  The content of the polyvinyl butyral resin used in the present invention is preferably 50% or more with respect to the total resin content in the oil-based ballpoint pen composition, and is preferably used as the main resin. This is because when the content of the polyvinyl butyral resin becomes less than 50% of the total resin content, the formation of the resin film on the tip of the chip is inhibited by other resins, so that the ink dripping cannot be suppressed, and the elasticity is further increased. This is because the formation of a certain ink layer is hindered, and the effect of improving the writing quality is not easily obtained. Considering the tendency of ink drooping performance and writing quality to be improved, the content of polyvinyl butyral resin is preferably 70% or more with respect to the total resin content, and further considering that tendency, 90% or more. preferable.

Moreover, it is preferable that polyvinyl butyral resin shall be the amount of hydroxyl groups 25 mol% or more. This is because the polyvinyl butyral resin having a hydroxyl group content of 25 mol% or more is stable over time with the salt-forming dye used in the present invention, and is thick at the tip end when the tip end is left in the atmosphere. This is because by forming a resin film and covering the gap between the ball and the tip of the chip, ink dripping can be suppressed. On the other hand, a polyvinyl butyral resin having a hydroxyl group content of less than 25 mol is not sufficiently soluble in an organic solvent and is not a uniform resin film, so that it is difficult to obtain a sufficient effect of suppressing ink dripping. It is because it is preferable to use this polyvinyl butyral resin. Moreover, the polyvinyl butyral resin having a hydroxyl group content of 30 mol% or more is preferable because the writing quality is easily improved. This is because, during writing, frictional heat is generated by the rotation of the ball, the ink at the tip of the chip is warmed, and the temperature of the ink increases, but the polyvinyl butyral resin is different from other resins, Even if the ink temperature rises, it has the property of making it difficult to lower the ink viscosity, and an ink layer that is always elastic is formed between the ball and the ball seat, making it difficult to make direct contact. It tends to be easy. In particular, oil-based ballpoint pens are effective with oil-based ballpoint pens because writing is often performed with high writing pressure. Further, when a polyvinyl butyral resin having a hydroxyl group content exceeding 40 mol% is used, the amount of moisture absorption tends to increase, and the temporal stability with the oil-based ink component tends to be affected. Therefore, a polyvinyl butyral resin having a hydroxyl amount of 30 to 40 mol% is preferable, and a hydroxyl group amount of 30 to 36 mol% is more preferable.
The hydroxyl content (mol%) of the polyvinyl butyral resin is the content of hydroxyl groups (mol%) with respect to the total molar amount of butyral groups (mol%), acetyl groups (mol%), and hydroxyl groups (mol%). Indicates the rate.

  Further, regarding the average degree of polymerization of the polyvinyl butyral resin, when the average degree of polymerization is 200 or more, the ink drooping performance is improved, and the ball becomes difficult to directly contact the ball seat due to the action of viscoelasticity. There is a tendency to improve the taste. On the other hand, if the average degree of polymerization exceeds 2500, the ink viscosity tends to be too high and the writing quality tends to be affected. Therefore, the average degree of polymerization is preferably 200 to 2500. Furthermore, when the average degree of polymerization is 800 or more, it is preferable that the ink is easily placed on the paper surface, and it is easy to maintain a three-dimensional handwriting and easily obtain a dark handwriting when transferred to a paper surface. For example, the average degree of polymerization is preferably 2000 or less. Therefore, the average degree of polymerization is preferably 800 to 2000, and when the average degree of polymerization is 1200 or more, the ink dripping performance tends to be improved, and thus the average degree of polymerization is most preferably 1200 to 2000. Here, the average degree of polymerization means the number of basic units constituting one molecule of the polyvinyl butyral resin, and a value measured based on the method defined in JIS K6728 (2001 version) can be adopted. .

  As for the polyvinyl butyral resin, specifically, trade names manufactured by Sekisui Chemical Co., Ltd .; ESREC BH-3 (hydroxyl group amount: 34 mol%, average degree of polymerization: 1700), BH-6 (hydroxyl group amount: 30 mol%). , Average polymerization degree: 1300), BX-1 (hydroxyl group amount: 33 ± 3 mol%, average polymerization degree: 1700), BX-5 (hydroxyl group quantity: 33 ± 3 mol%, average polymerization degree: 2400), BM -1 (hydroxyl group amount: 34 mol%, average degree of polymerization: 650), BM-2 (hydroxyl group amount: 31 mol%, average degree of polymerization: 800), BM-5 (hydroxyl group amount: 34 mol%, average degree of polymerization: 850) ), BL-1 (hydroxyl group amount: 36 mol%, average polymerization degree: 300), BL-1H (hydroxyl group amount: 30 mol%), BL-2 (hydroxyl group amount: 36 mol%, average polymerization degree: 450), Same B L-2H (hydroxyl content: 29 mol%), BL-10 (hydroxyl content: 28 mol%), etc., trade name of Kuraray Co., Ltd .; Mobital B20H (hydroxyl content: 26-31 mol%, average degree of polymerization: 250) -500), 30T (hydroxyl group amount: 33-38 mol%, average polymerization degree: 400-650), 30H (hydroxyl group amount: 26-31 mol%, average polymerization degree: 400-650), 30HH (hydroxyl group amount: 30-34 mol%, average polymerization degree: 400-650), 45H (hydroxyl group amount: 26-31 mol%, average polymerization degree: 600-850), 60T (hydroxyl group amount: 34-38 mol%, average polymerization degree: 750) -1000), 60H (hydroxyl group amount: 26-31 mol%, average degree of polymerization: 750-1000), 75H (hydroxyl group amount: 26-31 mol%, average degree of polymerization: 1). 00-1750), and the like. You may use these individually or in mixture of 2 or more types.

  If the content of the polyvinyl butyral resin is less than 3.0% by mass relative to the total amount of the ink composition, the amount of resin film formation may be insufficient, and the ink drooping performance tends to be inferior, and exceeds 40.0% by mass. Since the solubility in the ink tends to be inferior, 3.0 to 40.0% by mass is preferable with respect to the total amount of the ink composition. Furthermore, if considering the ink drooping performance, 10.0% by mass or more is preferable, and if it exceeds 30.0% by mass, the ink viscosity tends to be too high and affects the writing quality. 0% by mass is preferable, and 12.0 to 25.0% by mass is most preferable in consideration.

    As the resin other than the polyvinyl butyral resin, an ink viscosity adjusting resin or a spinnability imparting resin may be appropriately used. In particular, by blending a spinnability imparting resin, it is preferable to contain a spinnability imparting resin, because it enhances the binding property of the ink and easily suppresses the occurrence of excess ink at the tip of the chip (crying blister). Furthermore, since it is hygroscopic, it is preferable because the formed film is softened by the salt-forming dye or the polyvinyl butyral resin, and the writing performance at the time of dry-up is easily improved. Examples of the spinnability-imparting resin include polyvinylpyrrolidone and the like, specifically, trade names manufactured by IS Japan Co., Ltd .; PVP K-15, PVP K-30, PVP K-90, and PVP K-120. Etc. You may use these individually or in mixture of 2 or more types.

  The content of the spinnability imparting resin used in the present invention is preferably 0.1 to 20.0% with respect to the total resin content in the oil-based ballpoint pen composition. This is because when the content of the spinnability imparting resin is less than 0.1% of the total resin content, there is a tendency that it is difficult to suppress the generation of excess ink (crying blur), and when it exceeds 20%, polyvinyl butyral It is easy to inhibit the effect of the resin, specifically, it inhibits the formation of the resin film on the tip of the chip and makes it difficult to suppress ink sag, and further inhibits the formation of a flexible ink layer, This is because the effect of improving writing quality is difficult to obtain. Considering the tendency to suppress excess ink, the content of the spinnability imparting resin is preferably 1.0 to 20.0% with respect to the total resin content, and ink drooping performance and writing quality are improved. Considering the tendency, 1.0 to 10.0% is preferable, and further considering the tendency, 2.0 to 7.0% is preferable.

  As for the organic solvent used in the present invention, it is easy to absorb moisture when a glycol ether solvent is used other than an alcohol solvent. Therefore, the formed film is softened by the salt-forming dye or the polyvinyl butyral resin, and dried up. This is preferable because the writing performance is easily improved. Therefore, in the present invention, it is preferable to use at least a glycol ether solvent and an alcohol solvent in combination. In particular, in view of improving lubricity, it is preferable to have an aromatic ring, and therefore it is preferable to use an aromatic glycol ether and an aromatic alcohol solvent in combination.

  In addition, the content of organic solvent tends to affect the writing performance even if there is too much aromatic alcohol solvent. On the other hand, if there is too much glycol ether, it will absorb moisture too much and the resin film becomes soft and ink dripping. It is easy to influence performance and ink aging stability. Therefore, considering the balance between writing performance and ink aging stability, when the content of the aromatic alcohol solvent is A and the content of the glycol ether solvent is B, the relationship is 1 ≦ A / B ≦ 10. In view of this, it is preferable that the relationship 1 ≦ A / B ≦ 5 is satisfied.

  Specific examples of the alcohol solvent include aromatic alcohol solvents such as benzyl alcohol, phenylethyl alcohol, methylphenyl carbinol, and phthalyl alcohol, methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t -Aliphatic alcohols such as butanol. Specific examples of glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol monophenyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol. Examples thereof include dimethyl ether, 3-methoxybutanol, 3-methoxy-3-methylbutanol and the like, and these organic solvents can be used alone or in combination of two or more.

   In addition to increasing the ink consumption, the relationship between the selection of the colorant and the ball diameter is also important for dark handwriting. When the ink consumption per 100 m of the oil-based ballpoint pen refill is M (mg) and the ball diameter is R (mm), the relationship is 40 ≦ M / R ≦ 100, It tends to be a darker handwriting. Further, regarding the relationship of 40 ≦ M / R ≦ 100, when 40> M / R, the ink consumption is not sufficient with respect to the ball diameter, and it is difficult to obtain a dark handwriting and good writing taste. When / R> 100, ink drips or crying occurs from the gap between the ball and the tip of the tip, which tends to affect handwriting dryness. Considering darker handwriting and ink sag, it is preferable that the relationship is 50 ≦ M / R ≦ 70. Specifically, when the ball diameter is R (mm) = 1.0 (mm), the ink consumption M (mg) per 100 m is set to M = 30 to 100 (mg). A relationship of 40 ≦ M / R ≦ 100 can be established.

In addition, the ink consumption is preferably 30 mg or more because when the ink consumption per 100 m is less than 30 mg, it is difficult to obtain a dark handwriting or good writing quality. Further, if the ink consumption per 100 m exceeds 100 mg, ink dripping is likely to occur from the gap between the ball and the tip of the tip, and crying is likely to occur, so 100 mg or less is preferable. More preferably, it is 40 to 70 mg. This is because 40 mg or more is preferable for making darker handwriting, and 70 mg or less is preferable in consideration of improving ink dripping performance and crying.
The ink consumption was measured using 5 test samples at a writing speed of 4 m / min under the conditions of 20 ° C., writing paper JIS P3201 writing paper, a writing angle of 70 ° and a writing load of 200 g. A writing test is performed, and the average value of the ink consumption per 100 m is defined as the ink consumption per 100 m.
The ball diameter is not particularly limited, but generally a ball of about 0.2 to 2.0 (mm) is used.

  Moreover, it is preferable that the moving amount | distance of the axial direction of the ball | bowl of the ball-point pen tip used for this invention shall be 5-20 micrometers. If it is less than 5 μm, it is difficult to set the relationship of 40 ≦ M / R, and it becomes difficult to obtain a dark handwriting and good writing taste. If it exceeds 20 μm, the relationship of M / R ≦ 100 is set. This is because it becomes difficult to affect the ink drooping performance, and in view of this, it is preferably 7 to 16 μm.

The ink viscosity of the ink composition for oil-based ballpoint pens of the present invention is not particularly limited, but when the ink viscosity at 20 ° C. and a shear rate of 5 sec ⁻¹ is less than 5000 mPa · s, it is difficult to suppress ink drooping. In addition, the polyvinyl butyral resin used in the present invention maintains the lubricity by forming an ink layer and improves the writing quality even at a high viscosity of 50000 mPa · s at 20 ° C. and a shear rate of 5 sec ⁻¹ . Therefore, the ink viscosity at 20 ° C. and a shear rate of 5 sec ⁻¹ is preferably 5000 to 50000 mPa · s. In particular, in addition to setting the ink viscosity to 5000 to 50000 mPa · s, the relationship of 40 ≦ M / R ≦ 100 is different from that of conventional ballpoint pens, thereby suppressing the rotational resistance of the ball more synergistically. This makes it easier to improve lubricity and writing quality. Further, the ink viscosity is more preferably 5000 to 35000 mPa · s in view of further improving the writing performance and writing quality at the time of dry-up, and further 15000 in consideration of the ink dripping performance and the writing quality. 35000 mPa · s is most preferable.

  By the way, in this invention, content of the said polyvinyl butyral resin shall be 50% or more with respect to content of all the resin in an oil-based ball-point pen ink composition, and content of the said spinnability provision resin is oil-based ball-point pen composition. The ink drooping performance is set to 0.1 to 20.0% with respect to the total resin content and the ink viscosity is set to 10,000 to 50,000 mPa · s and 40 ≦ M / R ≦ 100. As in the past, with a coil spring or the like in the chip body, the ball is always pressed against the inner wall surface of the tip of the chip, and the small gap between the ball and the tip of the chip is closed. In addition, it is not necessary to have a structure that suppresses ink drooping, and since an ink dripping restraining effect is obtained, it is not necessary to provide a coil spring or the like in the chip body. Leads to reduction of goods number, it can be suitably used for retractable and / or low-priced products.

  The colorant used in the present invention contains a phosphate ester-based surfactant, a secondary amine and / or a tertiary amine other than the salt-forming dye of the alkylbenzene sulfonic acid and the triarylmethane skeleton basic dye. Alternatively, any colorant (dye, pigment) that stabilizes the ink aging may be used. As for dyes, oil-soluble dyes, acid dyes, basic dyes, metal-containing dyes, direct dyes, and various salt-forming dyes, salt-forming dyes of acid dyes and basic dyes, organic acids and bases A salt-forming dye with an acidic dye, a salt-forming dye with an acid dye and an organic amine, or the like can be used. Examples of the pigment include inorganic, organic and processed pigments. These dyes and pigments can be used in combination of two or more.

  Among the colorants, it is preferable to use only the dye in consideration of the stability of the alkylbenzene sulfonic acid and the salt-forming dye of the triarylmethane skeleton basic dye. Furthermore, considering the stability, the salt-forming dye of the alkylbenzene sulfonic acid and the triarylmethane skeleton basic dye is a salt-forming dye of an organic acid and a basic dye, so that the ink aging stability is considered. In this case, it is preferable to use a salt-forming dye of an organic acid and a basic dye having the same configuration.

  In addition, in the ink composition according to the present invention, as other additives, in order to improve lubricity and ink aging stability, (i) surfactants such as fluorine surfactants, silicone surfactants, A fatty acid alkanolamide, a fatty acid, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, an anionic surfactant and / or a salt-form of a cationic surfactant, (ii) Viscosity modifiers such as pseudoplasticity agents such as fatty acid amides, hydrogenated castor oil, and (iii) colorant stabilizers, (iv) plasticizers, (v) chelating agents, or (vi) water as a co-solvent Etc. may be used as appropriate. These may be used alone or in combination of two or more.

Further, the arithmetic average roughness (Ra) of the ball surface used in the present invention is preferably 0.1 to 15 nm. This is because when the arithmetic average roughness (Ra) is less than 0.1 nm, it is difficult to place ink sufficiently on the surface of the ball, and it is difficult to obtain a dark handwriting at the time of writing. When the roughness (Ra) exceeds 15 nm, the ball surface is too rough, and the rotational resistance between the ball and the ball seat is large, so the writing quality tends to be inferior, and the writing performance such as blurring, line skipping, and line unevenness in the handwriting. It is because it becomes easy to have an influence on. In particular, when the average degree of polymerization of the polyvinyl butyral resin is 1200 to 2000 and the average degree of polymerization is high, the cohesive force of the ink tends to increase, so that the arithmetic average roughness (Ra) is 1-15 nm on the ball surface. It is more preferable because the ink is easily placed thereon. Considering that more, 3 to 13 nm is preferable, and 3 to 10 nm is more preferable.
In addition, the measurement of surface roughness can be calculated | required by (model name SPI3800N by Seiko Epson Corporation).

  The material used for the ball is not particularly limited, but a cemented carbide ball mainly composed of tungsten carbide, a metal ball such as stainless steel, a ceramic such as silicon carbide, silicon nitride, alumina, silica, zirconia, etc. Ball, ruby ball and the like. It is preferable to use ceramic balls in consideration of writing taste, ball seat wear, and stability over time. The diameter of the ball is not particularly limited, but is generally about 0.25 mm to 2.0 mm.

  Ballpoint pen tip materials include metal materials such as stainless steel, white, brass, aluminum bronze, and aluminum, and resin materials such as polycarbonate, polyacetal, and ABS. In consideration of the properties, a white chip body is preferable, and in consideration of ball seat wear and stability over time, a stainless steel chip body is preferable.

  The ink container used in the present invention is limited in materials that can be employed from the viewpoint of chemical resistance, moisture permeability, air permeability, and the like. In that respect, it is preferable to conventionally use polypropylene as a material. However, when the salt-forming dye of alkylbenzene sulfonic acid and triarylmethane skeleton basic dye used in the present invention is used, it has a very strong affinity with the polypropylene ink container and the ink moves in the ink container. At this time, since the ink easily adheres to the inner wall and more easily adheres to the inner wall, the remaining amount of the ink is difficult to understand. In particular, when the polyvinyl butyral resin and the salt-forming dye are used in combination, they easily adhere to each other. For this reason, when polypropylene is used as the ink containing cylinder, it is preferable to treat the inner wall of the ink containing cylinder with silicone. This is because the silicone is applied to the inner wall of the ink storage cylinder so that the polypropylene, which is the storage cylinder material, does not come into direct contact with the ink, but maintains the relationship in which silicone is interposed in the middle, and is stored when the ink moves. It is possible to prevent adhesion to the inner wall of the cylinder.

  Examples of the silicone material include dimethyl silicone, methyl phenyl silicone, methyl hydrogen silicone, alkyl aralkyl silicone, polyether silicone, and high fatty acid ester fatty acid silicone. Among them, adhesion prevention is excellent and non-reactive. In view of the stability of the oil-based ink component, alkylaralkyl silicone is preferable. The most effective application method is to apply uniformly to the inner wall at the time of extrusion.

Next, an Example is shown and this invention is demonstrated.
The oil-based ballpoint pen ink composition of Example 1 is a dye as a colorant, an alcohol solvent as an organic solvent, a glycol ether solvent, a polyvinyl butyral resin, a phosphate ester surfactant as a lubricant, an alkylamine as an organic amine, Polyvinylpyrrolidone was employed as the spinnability-imparting resin, and a predetermined amount thereof was weighed and heated to 60 ° C., and then completely dissolved using a disper stirrer to obtain an ink composition for an oil-based ballpoint pen. Specific blending amounts are as follows.
Ink viscosity of Example 1 was measured using a viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield Co., Ltd. in an environment of 20 ° C. and a shear rate of 5 sec ⁻¹ (rotation speed: 2.5 rpm). As a result, the ink viscosity was 23000 mPa · s.
In addition, the ink consumption (M) per 100 m of Example 1 was 50 mg / 100 m and M / R = 50 when a spiral writing test was performed with a ballpoint refill with a ball diameter (R) of 1.0 mm. .
In Example 1, when the total amine value of the organic amine was X and the acid value of the phosphate ester surfactant was Y, Y / X = 0.32 to 0.39. .

Example 1
Colorant (dye, salt-forming dye of alkylbenzene sulfonic acid and triarylmethane skeleton basic dye) 10.0% by mass
Alcohol solvent (benzyl alcohol) 52.0 mass%
Glycol ether solvent (ethylene glycol monophenyl ether) 14.5% by mass
Polyvinyl butyral resin (ESREC BL-1, hydroxyl group amount: 36 mol%, average degree of polymerization: 300) 20.0 mass%
Lubricant (phosphate-based surfactant) 2.0% by mass
Organic amine (alkylamine) 1.0% by mass
Spinnability imparting resin (polyvinylpyrrolidone resin) 0.5% by mass

Examples 2-11
As shown in Tables 1 and 2, oil-based ballpoint pen ink compositions of Ink Examples 2 to 11 were obtained in the same procedure as Example 1 except that each component was changed. The measurement and evaluation results are shown in the table.
Moreover, in Examples 2-11, when the total amine value of the said organic amine is set to X and the acid value of the said phosphate ester type surfactant is set to Y, in the range of Y / X = 0.2-0.8. there were.

Comparative Examples 1-6
As shown in Table 3, oil-based ballpoint pen ink compositions of Comparative Examples 1 to 6 were obtained in the same procedure as in Example 1 except that each component was changed. The measurement and evaluation results are shown in the table.

Test and Evaluation Ink receiving cylinder 2 in which the ink composition for oil-based ballpoint pens prepared in Examples 1 to 11 and Comparative Examples 1 to 6 was applied to the inner wall of an ink receiving cylinder (made of polypropylene) with silicone (momentive performance materials). A ball-point pen tip 4 having a ball 3 (φ1.0 mm) having a ball diameter of 6 nm in arithmetic average roughness (Ra) on the surface of the ball is rotatably mounted on the tip of the ink storage cylinder 2 and 1 oil ballpoint pen ink 10 (0.2 g) was directly stored and ballpoint refill 1 was placed on an oil ballpoint pen (trade name: Supergrip) manufactured by Pilot Corporation to produce and write an oil ballpoint pen. The following tests and evaluations were performed using writing paper JIS P3201 as a test paper.

  Specifically, the ball-point pen tip 4 is formed by cutting a stainless steel wire having a diameter of 2.3 mm and a hardness of 230 Hv to 280 Hv to a desired length, and radiating from the ball holding chamber 6, the ink circulation hole 7, and the ink circulation hole 7. After forming the ink flow groove 8 extending in the direction of the ball, a substantially circular arc-shaped ball seat 9 is formed on the bottom wall of the ball holding chamber 6. Thereafter, the ball 3 of silicon nitride material is placed on the ball seat 9 and the tip end portion 5 is caulked inward.

  Further, the ball protrusion H from which the ball 3 protrudes from the tip end in a state where the ball 3 is placed on the ball seat 9 is 30.0% of the ball diameter, the caulking angle α is 70 degrees, and the vertical clearance of the ball 3 Is 15 μm, the inner diameter of the ball holding chamber is 104.0% of the ball diameter, and the diameter of the ball seat 9 is 86.0% of the ball diameter.

Dry-up performance test: After leaving for 2 weeks at 50 ° C. with the pen tip out, the state of handwriting when handwritten writing was evaluated.
There is no blur in the handwriting, and the handwriting is good.
Scratches appear in the handwriting, but there are no problems ...
Scratches in handwriting ... △
Scratch in the handwriting ・ ・ ・ ×

Ink aging test: Each oil-based ballpoint pen ink composition was placed in a 15 mm diameter closed glass test tube, allowed to stand at room temperature for 1 month, and then an appropriate amount was collected, and the ink was observed under a microscope.
Dissolved and stable, free of separation and precipitates
Separation and precipitation occurred slightly, but good ones ...
Separation or precipitation occurred, but there was no problem in practical use.
Separation or precipitation occurs and cannot be converted to ink, or causes poor writing ・ ・ ・ ×

Ink sag test: The ink was left for 7 days under an environment of 30 ° C. and 85% RH for 7 days to confirm ink leakage from the tip of the tip.
There are no ink droplets at the tip of the tip.
Ink droplets at the tip of the tip are within 1/4 of the taper.
Ink droplets at the tip of the tip are 1/4 or more and 1/2 of the taper part ... △
Ink drop on tip of tip is more than 1/2 of taper part ・ ・ ・ ×

Written taste: A hand-written sensory test was performed and evaluated.
Very smooth ・ ・ ・ ◎
What is smooth ・ ・ ・ ○
Smoothness of a level that is not a problem for practical use ・ ・ ・ △
Heavy thing

  In Examples 1 to 11, good performance was obtained in both dry-up performance test, ink aging test, ink sag test, and writing taste.

  In Comparative Examples 1 and 2, since the phosphate ester-based surfactant was not used, the dry-up performance test was poor, handwriting was generated, and the writing taste was heavy.

  In Comparative Examples 3 and 4, since no organic amine was used, the phosphoric ester surfactant was not sufficiently neutralized, and reacted with the ink component to generate precipitates.

  In Comparative Example 5, since a primary amine was used, it reacted with the ink component, and the ink aging was poor.

  In Comparative Example 6, since a salt-forming dye of an alkylbenzene sulfonic acid and a triarylmethane skeleton basic dye was not used, the compatibility with organic amine was poor and the ink aging was poor.

Comparative Example 7
Although not shown in the table, the ballpoint pens of each of the examples and the comparative examples move the ink containing cylinder as the ink is consumed when the writing test is performed. Since the ink was applied to the inner wall (made of polypropylene), the ink did not adhere to the inner wall of the ink containing cylinder, so the remaining amount of ink could be clearly confirmed. On the other hand, as Comparative Example 8, when a writing test was performed with a ballpoint pen that was not applied to the inner wall of the ink containing cylinder (made of polypropylene) with silicone using the oil-based ballpoint pen ink composition of Example 1, the ink was found to be on the inner wall of the ink containing cylinder. The remaining amount of ink was not known.

  In addition, when using an oil-in-oil type ballpoint pen such as a knock-type oily type ballpoint pen or a rotary feed-out type oily type ballpoint pen, the ink drooping performance is one of the most important performances. It is effective to use an oil-based ballpoint pen which can be formed and covered with a gap between the ball and the tip of the chip to improve the ink drooping performance.

  Further, in this embodiment, for the sake of convenience, an oil ballpoint pen containing an oil ballpoint pen refill that directly contains an ink composition for an oil ballpoint pen is illustrated in the shaft tube, but the oil ballpoint pen of the present invention includes a shaft tube. A direct-packing type oil-based ballpoint pen may be used in which an ink-containing tube is used and the ink composition for an oil-based ballpoint pen is directly stored in the shaft tube. Further, in this embodiment, for the sake of convenience, a ballpoint pen tip formed by cutting a wire rod is illustrated, but a ballpoint pen tip formed by pressing a pipe member may be used.

  In this embodiment, the caulking angle of the ball-point pen tip is set to 70 degrees. However, if the caulking angle is too large, the paper contact angle tends to decrease, and therefore the angle is 90 degrees or less, preferably 80 degrees or less. preferable. If the caulking angle is 50 degrees or less, the space for storing ink between the ball 9 and the tip edge of the chip tends to be small, and it is difficult for ink to return, and it is difficult to suppress ink scooping, so the caulking angle is 50 degrees. It is preferable that the angle be -90 degrees.

  Further, the inner diameter of the ball exit and ball holding chamber is not particularly limited, but when the oil consumption per 100 m of the oil-based ballpoint refill is M (mg) and the ball diameter is R (mm) In order to satisfy the relationship of 40 ≦ M / R ≦ 100, the ball exit is 10.0 to 30.0% of the ball diameter, and the inner diameter of the ball holding chamber is 100.0 to 110.0 of the ball diameter. %, The ball seat diameter is preferably 70 to 95% of the ball diameter.

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

DESCRIPTION OF SYMBOLS 1 Ball-point pen refill 2 Ink storage cylinder 3 Ball 4 Ball-point pen tip 5 Tip end part 6 Ball holding chamber 7 Ink distribution hole 8 Ink distribution groove 9 Ball seat 10 Oil-based ball-point pen ink H Ball out α Caulking angle

Claims (11)

At least a colorant, an organic solvent, a resin, a phosphate ester surfactant, and an organic amine. The colorant is a salt-forming dye of an alkylbenzenesulfonic acid and a triarylmethane skeleton basic dye, and the organic amine is secondary. 0.1 ≦ Y / X ≦ 1.0, where X is the total amine value of the organic amine, and Y is the acid value of the phosphate ester surfactant. An oil-based ballpoint pen ink composition, wherein the resin contains at least a polyvinyl butyral resin, and the content of the polyvinyl butyral resin is 70% or more based on the total resin content. The ink composition for oil-based ballpoint pens according to claim 1 , wherein the organic solvent is an alcohol solvent. The secondary amine and / or tertiary total amine value of the amine is, 70~300 (mgKOH / g) oil-based ink composition for a ballpoint pen according to claim 1 or 2, characterized in that a. Wherein the resin is at least spinnability imparting resin, the content of該曳yarn imparting resin of claims 1 to 3, characterized in that from 0.1 to 20 mass% relative to the content of total resin The ink composition for oil-based ballpoint pens according to any one of the above. When the organic solvent contains at least an alcohol solvent and a glycol ether solvent, the content of the alcohol solvent is A, and the content of the glycol ether solvent is B, the relationship is 1 ≦ A / B ≦ 10. The ink composition for oil-based ballpoint pens according to any one of claims 1 to 4 . 20 ° C., the ink viscosity at a shear rate of 500 sec ^-1, oil-based ink composition for a ballpoint pen according to any one of claims 1, characterized in that a 15000~35000mPa · s 5. The oil-based property according to any one of claims 1 to 6 , wherein a ballpoint pen tip that rotatably holds a ball is attached to the tip of the ink storage cylinder directly or via a chip holder, and the ink storage cylinder according to any one of claims 1 to 6. An oil-based ballpoint pen refill containing an ink composition for ballpoint pens, wherein an ink consumption amount per 100 m of the oil-based ballpoint pen refill is 30 to 100 mg. The oil ballpoint pen refill according to claim 7 , wherein an amount of movement of the ball in the axial direction is 5 to 20 μm. 9. The oil-based ballpoint pen refill according to claim 7, wherein an arithmetic average roughness of a surface of the ball is 0.1 to 15 nm. 10. An oil-based ballpoint pen comprising the oil-based ballpoint pen refill according to claim 7 disposed in a shaft cylinder. The oil-based ballpoint pen refill according to claim 7 is slidably disposed in a shaft cylinder, and is a retractable oil-based ballpoint pen in which a tip end portion of the ballpoint pen tip can be projected and retracted from the tip end portion of the shaft cylinder. An oil-based ballpoint pen.

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