JP6706364B2 - Oil-based ballpoint pen refill and oil-based ballpoint pen using the refill - Google Patents

Description

The present invention relates to an oil-based ballpoint pen refill and an oil-based ballpoint pen using the refill.

Conventionally, in an oil-based ink composition for an oil-based ball-point pen, an ink composition for an oil-based ball-point pen that uses various dyes such as a nigrosine dye as a coloring agent for producing a dark handwriting, and an ink composition for an oil-based ball-point pen in which an ink discharge amount is set Technology is proposed.

Techniques using a nigrosine dye as such an ink composition for an oil-based ballpoint pen include JP-A-7-188601 "Ink composition for oil-based ballpoint pen" and JP-A-8-157765 "Ink composition for oil-based ballpoint pen". "Article" and the technique of setting the ink discharge amount are disclosed in JP-A 2011-153199, "Ink for ballpoint pen".

"JP-A-7-188601" "JP-A-8-157765" "Japanese Patent Laid-Open No. 2011-153199" "Japanese Patent Laid-Open No. 9-71745"

However, in Patent Documents 1 and 2, when a nigrosine dye is used as a colorant, it is possible to darken the handwriting to some extent, but it is not sufficient, and therefore it is necessary to increase the content of the nigrosine dye. In this case, the viscosity of the ink was high, the writing quality was poor, and there was the problem of dye solubility in organic solvents.

Further, in Patent Document 3, with a ball-point pen ink in which the ink discharge amount per 200 m is set to 32 to 47 mg (16 to 23.5 mg in terms of 100 m), the density of the handwriting is not sufficient by itself, and darker handwriting. Was required.

Further, as a technique for specifying the colorant, in Patent Document 4, in the case of using a salt-forming dye of a triarylmethane-based basic dye and an azo-based yellow acidic dye, an aliphatic alcohol, or a urethane-modified ketone-formaldehyde resin as the colorant. However, the dissolution stability is inferior, there is a problem in ink stability over time, and since the ink of Patent Document 4 is used for ink jets and markers, if it is used as it is for a ballpoint pen, the lubricity is poor, The writing quality was poor and ink dripping occurred.

Regarding the selection of ink components such as colorants, organic solvents, surfactants, and resins as in Patent Documents 1, 2, and 4, there is compatibility with each component, and depending on one component, ink stability over time, This is a very important structure because it has a great effect on lubricity. Further, in order to obtain a thick handwriting, not only the ink consumption amount is increased as in Patent Document 3, but also a thick handwriting can be made depending on the kind of the colorant, and further depending on the ball diameter. The balance with the diameter of the ball is an important structure for producing a thick handwriting.

An object of the present invention is to provide an oil-based ballpoint pen refill that is excellent in ink aging stability, ink dripping, and writing quality with dark handwriting, and an oil-based ballpoint pen using the same.

The present invention, in order to solve the above problems,
"1. A ball-point pen tip that rotatably holds a ball is attached to the tip of the ink container directly or through a chip holder, and at least a colorant, an organic solvent, and a phosphate ester-based interface is provided in the ink container. An oily ballpoint pen refill containing an ink composition for an oily ballpoint pen comprising an activator and an organic amine, wherein the colorant is a salt-forming dye of an azo skeleton acidic dye and a basic dye, and the oily ballpoint pen When the ink consumption per 100 m of refill is M (mg) and the ball diameter is R (mm), there is a relationship of 40≦M/R≦100, and the oil-based ballpoint pen at 20° C. and a shear rate of 5 sec ⁻¹ . An oil-based ballpoint pen refill, wherein the ink viscosity of the ink composition is 10,000 to 50,000 mPa·s.
2. 2. The oil-based ballpoint pen refill according to item 1, wherein the azo skeleton acid dye is a diazo skeleton acid dye.
3. 3. The oil-based ballpoint pen refill according to claim 1 or 2, wherein the oil-based ballpoint pen ink composition contains a spinnability imparting resin.
4. The oil-based ballpoint pen refill according to any one of claims 1 to 3, wherein the ink composition for an oil-based ballpoint pen contains a polyvinyl butyral resin.
5. The oil-based ballpoint pen refill according to any one of claims 1 to 4, wherein the inner wall of the ink container of the oil-based ballpoint pen refill according to any one of claims 1 to 4 is coated with silicone. ..
6. An oil-based ballpoint pen comprising the oil-based ballpoint pen refill according to any one of claims 1 to 5 disposed in a barrel. ".

INDUSTRIAL APPLICABILITY The present invention can provide an ink composition for oil-based ballpoint pens, which is excellent in ink aging stability, ink dripping, and writing quality with dark handwriting, and an oil-based ballpoint pen using the same.

It is a longitudinal cross-sectional view of a ball-point pen refill according to the present invention. FIG. 2 is an enlarged vertical sectional view of a main part of FIG. 1 with some parts omitted.

A feature of the present invention is that a ball-point pen tip rotatably holding a ball is attached to the tip of the ink containing cylinder directly or via a chip holder, and at least a coloring agent, an organic solvent, phosphoric acid is contained in the ink containing cylinder. Ester-based surfactant, an oil-based ballpoint pen refill containing an ink composition for an oil-based ballpoint pen consisting of an organic amine, wherein the colorant is a salt-forming dye of an azo skeleton acidic dye and a basic dye, and When the ink consumption per 100 m of the oil-based ballpoint pen refill is M (mg) and the ball diameter is R (mm), there is a relationship of 40≦M/R≦100 at 20° C. and a shear rate of 5 sec ⁻¹ . The ink composition for an oil-based ballpoint pen has an ink viscosity of 10,000 to 50,000 mPa·s, which is an oil-based ballpoint pen refill.

As described above, in order to obtain dark handwriting, it is conceivable to increase the concentration of the colorant and eject a large amount of ink onto the paper surface, but if the concentration of the colorant is increased, the ink stability over time tends to decrease. In view of these problems, the present invention uses a specific colorant, a phosphoric acid ester-based surfactant, and an organic amine in consideration of the balance between the ink consumption amount per 100 m and the ball diameter, and the ink viscosity. The present invention solves the above-mentioned problems by improving the ink stability over time, the ink dripping, and the writing quality with dark handwriting.

Regarding the colorant used in the present invention, there are dyes and pigments, but when a dye is used, it is easy to obtain a deep and fresh handwriting, and when a pigment is used, in order to obtain pigment dispersion stability, Since there are problems such as selection and cost, it is preferable to use at least a dye. With respect to the type of dye, there may be mentioned a salt-forming dye of an acid dye and a basic dye, a salt-forming dye of an organic acid and a basic dye, a salt-forming dye of an acid dye and an organic amine, but in a small amount. Considering that dark handwriting can be obtained, it is preferable to use a salt forming dye of an acid dye and a basic dye.

Among the salt-forming dyes of acid dye and basic dye, it is necessary to use the salt-forming dye of azo skeleton acid dye and basic dye. It has a strong ionic bond between the azo skeleton acid dye and the basic dye, and is a stable salt-forming dye, so it is stable in oil-based inks, and is neutralized by the azo skeleton acid dye and the basic dye. This is because it is preferable to use the salt forming dye.

Further, the salt forming dye of an azo skeleton acidic dye and a basic dye, as the basic dye, a basic dye such as a xanthene skeleton, a triarylmethane skeleton, an azomethine skeleton, an azo skeleton, an anthraquinone skeleton, an oxazine skeleton and the like. It is obtained by forming a salt of these basic dyes and an azo skeleton acidic dye.

In the present invention, it is not enough to increase the ink consumption amount to obtain a dark handwriting, and the relation between the selection of the colorant and the ball diameter is also important. When a salt-forming dye of an azo skeleton acidic dye and a basic dye is used and the ink consumption per 100 m of the oil-based ballpoint pen refill is M (mg) and the ball diameter is R (mm), 40≦ It was found that the relation of M/R≦100, which is different from the conventional one, gives a strong handwriting. In particular, by using the salt-forming dye of the azo skeleton acidic dye and the basic dye and satisfying the relation of 40≦M/R≦100, darker handwriting can be obtained, which is an important constitution in the present invention. .. Regarding the relationship of 40≦M/R≦100, when 40>M/R, the ink consumption is insufficient with respect to the ball diameter, and dark handwriting and good writing quality cannot be obtained. If the salt-forming dye of azo skeleton acid dye and basic dye cannot be obtained sufficiently and M/R>100, ink drips from the gap between the ball and the tip of the chip, crying fluff occurs, and handwriting dryness Is also easily affected. Considering darker handwriting and ink dripping, it is preferable that the relationship of 50≦M/R≦70 is satisfied. As a specific example, when the ball diameter is R (mm)=1.0 (mm), the ink consumption amount M (mg) per 100 m is M=30 to 100 (mg), The relationship may be 40≦M/R≦100.

Also, regarding the ink consumption amount, if the ink consumption amount per 100 m is less than 30 mg, it is difficult to obtain dark handwriting and good writing quality. Further, when the ink consumption per 100 m exceeds 100 mg, the ink drips easily from the gap between the ball and the tip of the chip, and the crying fluff easily occurs, so 100 mg or less is preferable. More preferably, it is 40 to 70 mg. This is because it is preferably 40 mg or more for thicker handwriting, and 70 mg or less is preferable in view of improving ink dripping performance and crying fluff.
Regarding the ink consumption, a spiral of 5 test samples was used at a writing speed of 4 m/min at a writing angle of 70° on a writing paper JIS P3201 writing paper 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.

The amount of movement of the ball of the ballpoint pen tip used in the present invention in the axial direction of the ball is preferably 5 to 20 μm. If it is less than 5 μm, it becomes difficult to set the relationship of 40≦M/R, and it becomes difficult to obtain dark handwriting and good writing quality. If it exceeds 20 μm, the relationship of M/R≦100 is set. This is because it becomes difficult and the ink dripping performance is easily affected. From this point of view, 7 to 16 μm is preferable.

As the organic solvent used in the present invention, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol monophenyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, 3 -Glycol ether solvents such as methoxybutanol and 3-methoxy-3-methylbutanol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, glycol solvents such as ethylene glycol, benzyl alcohol, methanol , Ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t-butanol, propanol alcohol, allyl alcohol, 3-methyl-1-butyn-3-ol, ethylene glycol monomethyl ether acetate and other higher alcohols Examples thereof include organic solvents commonly used as oil-based inks for ballpoint pens, such as alcohol solvents.

Examples of the resin used in the present invention include polyvinyl butyral resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, polyvinylpyrrolidone resin, ketone resin, terpene resin, alkyd resin, phenoxy resin, polyvinyl acetate resin, etc. It is important to use at least a polyvinyl butyral resin in order to improve performance and writing quality. Regarding polyvinyl butyral resin, polyvinyl alcohol (PVA) is reacted with butyraldehyde (BA), butyral group, acetyl group, a structure having a hydroxyl group, as a conventional technology, polyvinyl butyral resin as a pigment Although there is a technique which is preferably used as a dispersant, the present invention improves the ink dripping performance and writing quality.

This is because polyvinyl butyral resin forms a resin film at the tip of the chip and covers the gap between the ball and the tip of the chip to prevent ink dripping, and also to provide an ink that is always elastic between the ball and the ball seat. This is because a layer is formed to make it difficult to make direct contact with each other, and thus it becomes possible to easily improve writing quality. Further, the polyvinyl butyral resin is preferable because it has good compatibility with the salt-forming dye of the azo skeleton acidic dye and the basic dye and is excellent in stability over time. However, some polyvinyl butyral resins have poor compatibility depending on the selection of the organic solvent and the surfactant, and in the oil-based ink, they may not be stable in dissolution and may be separated, so that the original effect may not be obtained. Be done.

When the salt-forming dye of the azo skeleton acidic dye and the basic dye used in the present invention is used in combination with the polyvinyl butyral resin, it is preferable to use an aromatic alcohol solvent as the organic solvent. This is because by using an aromatic alcohol solvent, the polyvinyl butyral resin and the salt-forming dye of the azo skeleton acidic dye and the basic dye are each dissolved and stabilized, and the ink is stable over time for a long time without being separated from each other. In addition, when the tip end is left in the atmosphere, a uniform thick resin film is formed on the tip end and the gap between the ball and the tip end is covered to further suppress ink dripping. This is because it becomes possible. On the other hand, when an aliphatic alcohol or the like is used, the solubility stability of the polyvinyl butyral resin and the salt forming dye of the azo skeleton acidic dye and the basic dye is likely to be poor, and there is a solvent with high volatility, and the ink aging stability Is easily inferior. Furthermore, the aromatic alcohol solvent is preferable because it has an aromatic ring and thus easily improves the lubricity. Therefore, it is preferable to use at least an aromatic alcohol solvent. Therefore, in the present invention, when using a salt forming dye of an azo skeleton acidic dye and a basic dye, or a polyvinyl butyral resin, it is preferable to contain an aromatic alcohol solvent.

The azo skeleton acid dye used in the present invention may be any acid dye having an azo group (-N=N-) in the molecule, and examples thereof include a diazo skeleton acid dye and a monoazo skeleton acid dye. Among them, the diazo skeleton acidic dye is a more stable salt-forming dye, which is combined with a basic dye, is difficult to separate and precipitate, and is preferable because the ink stability over time can be maintained for a long time. The presence of two —N═N—) is preferable because it has two double bonds, is hard to separate from the monoazo skeleton acidic dye, and is stable. Further, in consideration of lubricity, an azo skeleton acidic dye having an aromatic ring is preferable. Specifically, as the diazo skeleton acidic dye, C.I. I. Acid Red 97, 111, 114, 115, C.I. I. Acid Yellow 38, 42, 44 and monoazo skeleton acid dyes include C.I. I. Acid Yellow 11, 17, 25, 29, 36, 76, C.I. I. Acid Red 1, 6, 8, 9, 13, 14, 18 and the like. Among them, C.I. I. Acid Red 97111, 114, 115 are preferred.

Regarding the basic dye used in the present invention, it is preferable to use the triarylmethane skeleton acidic dye among the basic dyes. This is because the azo skeleton acid dye and a stronger ionic bond force tend to be a stable salt-forming dye.

The triarylmethane skeleton acidic dye is a basic dye having three aromatic rings such as phenyl group and naphthyl group on the same carbon, and specifically, C.I. I. Basic Blue 1, 5, 7, 19, 26, C.I. I. Basic Violet 1, 3, 4, 10, 15, C.I. I. Basic greens 1, 4, 7, etc. can be mentioned. Among them, in consideration of neutralization stability with an azo skeleton acidic dye, C.I. I. Basic violet 1, 3, 4, 10, 15 are preferred. Further, in consideration of safety, C.I. I. It is preferable to use Basic Violet 4, because this is a structure containing no Michler's ketone and there is no fear of carcinogenicity. Therefore, in consideration of neutralization stability, C.I. I. It is most preferable to use a salt-forming dye of Basic Violet 4 and an azo skeleton acid dye.

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

The content of the polyvinyl butyral resin used in the present invention is 50% or more with respect to the content of all the resins in the oil-based ballpoint pen composition, and it is preferably used as a main resin. This is because when the content of the polyvinyl butyral resin is less than 50% of the total resin content, the other resin hinders the formation of the resin film on the tip of the chip and prevents the ink from dripping, and the elasticity is further improved. This is because it hinders the formation of a certain ink layer, making it difficult to obtain the effect of improving the writing quality. Considering the tendency that the ink dripping performance and the writing quality are improved, the content of polyvinyl butyral resin is preferably 70% or more with respect to the content of all resins, and further 90% or more when the tendency is considered. preferable.

The polyvinyl butyral resin preferably has a hydroxyl group content of 25 mol% or more. This is because the above-mentioned polyvinyl butyral resin having a hydroxyl group content of 25 mol% or more forms a thick resin film at the tip of the tip when the tip is left in the air, and covers the gap between the ball and the tip. This is because it is easy to suppress ink dripping. On the other hand, a polyvinyl butyral resin having a hydroxyl group amount of less than 25 mol does not have sufficient solubility 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. This is because it is preferable to use the polyvinyl butyral resin. Further, the polyvinyl butyral resin having a hydroxyl group amount of 30 mol% or more is preferable because the writing feeling is easily improved. This is because at the time of writing, frictional heat is generated by the rotation of the ball, the ink at the tip of the tip is warmed and the temperature of the ink rises, 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.By forming an ink layer that is always elastic between the ball and the ball seat, making it hard to make direct contact, the writing feel is improved. Tends to be easy. In particular, the oil-based ball-point pen is effective because the oil-based ball-point pen often writes with a high writing pressure. When a polyvinyl butyral resin having a hydroxyl group content of more than 40 mol% is used, the amount of moisture absorption tends to increase, and the temporal stability with the oil-based ink component is likely to be affected. Therefore, a polyvinyl butyral resin having a hydroxyl group content of 40 mol% or less is preferred. Therefore, a polyvinyl butyral resin having a hydroxyl group amount of 30 to 40 mol% is preferable, and a hydroxyl group amount of 30 to 36 mol% is more preferable.
In addition, the amount of hydroxyl groups (mol %) of the polyvinyl butyral resin means the content of hydroxyl groups (mol %) with respect to the total amount of butyral groups (mol %), acetyl groups (mol %), and hydroxyl groups (mol %). It shows the rate.

Regarding the average degree of polymerization of the polyvinyl butyral resin, when the average degree of polymerization is 200 or more, the ink dripping performance is improved, and the cohesive force of the ink can be increased, so that the ink easily deposits on the ball surface, When the ink remains in the ball, the ink easily enters between the ball and the ball seat, and it becomes difficult for the ball to come into direct contact with the ball seat, which tends to improve the writing feel. 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. Further, when the average degree of polymerization is 800 or more, it is preferable that the ink is easily deposited, so that it is easy to maintain a three-dimensional handwriting when it is transferred to a paper surface and a thick handwriting is easily obtained. 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 therefore the average degree of polymerization is most preferably 1200 to 2000. Here, the average degree of polymerization refers to the number of basic units constituting one molecule of the polyvinyl butyral resin, and a value measured based on the method specified in JISK6728 (2001 version) can be adopted. ..

Regarding the polyvinyl butyral resin, specifically, trade name of Sekisui Chemical Co., Ltd.; S-REC BH-3 (amount of hydroxyl group: 34 mol%, average degree of polymerization: 1700), BH-6 (amount of hydroxyl group: 30 mol%) , Average degree of polymerization: 1300), BX-1 (hydroxyl group amount: 33±3 mol%, average degree of polymerization: 1700), same BX-5 (hydroxyl group amount: 33±3 mol%, average degree of polymerization: 2400), same BM -1 (hydroxyl group amount: 34 mol%, average polymerization degree: 650), BM-2 (hydroxyl group amount: 31 mol%, average polymerization degree: 800), BM-5 (hydroxyl group amount: 34 mol%, average polymerization degree: 850) ), the same BL-1 (hydroxyl group amount: 36 mol%, average degree of polymerization: 300), the same BL-1H (hydroxyl group amount: 30 mol%), the same BL-2 (hydroxyl group amount: 36 mol%, average degree of polymerization: 450), The same BL-2H (hydroxyl group amount: 29 mol%), the same BL-10 (hydroxyl group amount: 28 mol%) and the like, a trade name of Kuraray Co., Ltd.; Mobital B20H (hydroxyl group amount: 26 to 31 mol%, average degree of polymerization: 250-500), 30T (hydroxyl group amount: 33-38 mol%, average degree of polymerization: 400-650), 30H (hydroxyl group amount: 26-31 mol%, average degree of polymerization: 400-650), 30HH (hydroxyl group amount) : 30 to 34 mol%, average degree of polymerization: 400 to 650, 45H (hydroxyl group amount: 26 to 31 mol%, average degree of polymerization: 600 to 850), the same 60T (hydroxyl group amount: 34 to 38 mol%, average degree of polymerization: 750 to 1000), the same 60H (hydroxyl group amount: 26 to 31 mol%, average degree of polymerization: 750 to 1000), the same 75H (hydroxyl group amount: 26 to 31 mol%, average degree of polymerization: 1500 to 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 with respect to the total amount of the ink composition, the amount of resin film formed may be insufficient, and the ink dripping performance tends to be poor and exceeds 40.0% by mass. Since the solubility in the ink tends to be poor, 3.0 to 40.0 mass% is preferable with respect to the total amount of the ink composition. Further, in consideration of the ink dripping 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 the writing quality tends to be affected, so that 10.0 to 30. 0 mass% is preferable, and if further considered, 12.0 to 25.0 mass% is the most preferable.

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, it is preferable to contain the spinnability imparting resin, because the incorporation of the spinnability imparting resin enhances the binding property of the ink and easily suppresses the generation of excess ink (crying lumps) at the tip of the chip. Examples of the spinnability imparting resin include polyvinylpyrrolidone, and specifically, trade names of PSP K-15, PVP K-30, PVP K-90, and PVP K-120 manufactured by ISPE Japan K.K. And so on. 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 content of all the resins 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, it tends to be difficult to suppress the generation of excess ink (crying lumps) at the tip of the chip, and when it exceeds 20%. , It is easy to inhibit the effect of polyvinyl butyral resin, specifically, it inhibits the formation of the resin film at the tip of the tip, making it difficult to suppress ink dripping, and also inhibits the formation of an elastic ink layer. This is because it is difficult to obtain the effect of improving writing quality. 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 content of the total resin, and the ink dripping performance and the 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.

The ink viscosity of the ink composition for an oil-based ballpoint pen of the present invention is not particularly limited, but when the ink viscosity at 20° C. and a shear rate of 5 sec ⁻¹ is less than 5000 mPa·s, it is difficult to suppress ink dripping, Further, the polyvinyl butyral resin used in the present invention maintains the lubricity by forming an ink layer even when the ink viscosity is high at 20° C. and a shear rate of 5 sec ^{−1 to} be 50,000 mPa·s, thereby improving the writing quality. 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 the ink viscosity of 5000 to 50000 mPa·s, the relationship of 40≦M/R≦100, which is different from the conventional ball-point pen, suppresses the ball rotational resistance more synergistically. Because it is easy to do, it improves the lubricity and the writing feel. Further, in consideration of further improving the writing feel, the ink viscosity is more preferably 5000 to 35000 mPa·s, and further more preferably 15000 to 35000 mPa·s in consideration of the ink dripping performance and writing feel.

By the way, as in the present invention, a polyvinyl butyral resin is used, and the content of the polyvinyl butyral resin is 50% or more with respect to the content of all resins in the oil-based ballpoint pen ink composition, and the content of the spinnability imparting resin is The amount is 0.1 to 20.0% with respect to the total resin content in the oil-based ballpoint pen composition, the ink viscosity is 10,000 to 50,000 mPa·s, and the relationship of 40≦M/R≦100 is satisfied. This has the effect of significantly improving the ink dripping performance.Therefore, as in the past, the coil spring etc. in the chip body constantly presses the ball against the inner wall surface of the chip tip, and By closing such a gap, it is not necessary to have a structure that suppresses ink dripping, and the effect of suppressing ink dripping can be obtained.Therefore, it is not necessary to equip the chip body with a coil spring, etc., leading to a reduction in the number of parts. It can be preferably used for a retractable type and/or a low-priced product.

In the present invention, it is preferable to use a phosphate ester type surfactant. This is because in the phosphoric acid ester-based surfactant, the phosphoric acid group is easily adsorbed on the metal surface, the lubricity between the ball and the chip body is maintained, and the writing feel is more easily improved. In particular, in the present invention, as described above, the ink layer formed of poly(vinyl butyral) and the phosphoric acid group are more preferable because the lubricity is easily improved.

Examples of the phosphoric acid ester-based surfactant include phosphoric acid monoester of polyoxyethylene alkyl ether or polyoxyethylene alkylaryl ether, phosphoric acid diester of polyoxyethylene alkyl ether or polyoxyethylene alkylaryl ether, and polyoxyethylene alkyl ether. Or, a phosphoric acid triester of polyoxyethylene alkylaryl ether, an alkyl phosphoric acid ester, an alkyl ether phosphoric acid ester or a derivative thereof and the like can be mentioned. The alkyl group of the phosphoric acid ester type surfactant is a styrenated phenol type or nonylphenol type. System, lauryl alcohol system, tridecyl alcohol system, octylphenol system and the like. You may use these phosphate ester type surfactants individually or in mixture of 2 or more types. Among them, in consideration of lubricity, the number of carbon atoms contained in the alkyl group is preferably 5 to 18, further considered, the number of carbon atoms is more preferably 10 to 18, and most preferably, Considering the ink stability over time, the number of carbon atoms is 12 to 18. If the number of carbon atoms in the alkyl group is too small, the lubricity tends to be insufficient, and if the number of carbon atoms is too large, the stability of the ink over time tends to be affected, so caution is required.

Further, the phosphoric acid ester-based surfactant tends to soften the formed film, and may improve the writing performance during dry-up. The polyvinyl butyral resin used in the present invention is liable to have poor writing performance during dry-up due to the formed film. When a phosphate ester type surfactant is used, the formed film is softened and writing-out during dry-up is performed. Is preferable because it is easy to improve. In particular, in retractable writing instruments such as knock-type writing instruments and rotary feeding type writing instruments, unlike the cap-type writing instruments, the pen tip is always exposed to the outside, which easily affects the writing performance during dry-up. It is more preferable to use a phosphate ester surfactant.

Further, the content of the phosphoric acid ester-based surfactant is more preferably 0.1 to 5.0 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 lubricity tends to be difficult to obtain, and if it exceeds 5.0% by mass, the ink tends to become unstable over time. In consideration of the above, 0.3 to 3.0% by mass is preferable with respect to the total amount of the ink composition, and more consideration, 0.5 to 3.0% by mass is most preferable.

Specific examples of the phosphoric acid ester-based surfactant include PLYSURF A217E (alkyl group: C14, acid value: 45 to 58) and PLYSURF A217B from PLYSURF series (Daiichi Kogyo Seiyaku Co., Ltd.). (Alkyl group: C12, acid value: 44 to 58), A215C (alkyl group: C12, acid value: 80 to 95), A208B (alkyl group: C12, acid value: 135 to 155) ), A208N (alkyl group: mixture of 12 and 13 carbon atoms, acid value: 160 to 185), and phosphanol RB410 (alkyl group: carbon) from the phosphanol series (manufactured by Toho Chemical Industry Co., Ltd.). Number 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. You may use these surfactants individually or in mixture of 2 or more types.
The acid value is expressed in mg of potassium hydroxide required to neutralize the acidic components contained in 1 g of the sample.

As the organic solvent used in the present invention, it is preferable to use a glycol ether solvent because it easily absorbs moisture, so that the polyvinyl butyral resin softens the formed film and improves the writing performance during dry-up. Therefore, in the present invention, it is preferable to use at least a glycol ether solvent and an aromatic alcohol solvent in combination. In particular, from the viewpoint of improving lubricity, it is preferable to have an aromatic ring, and therefore it is preferable to use at least an aromatic glycol ether solvent and an aromatic alcohol solvent in combination.

Further, the content of the organic solvent, if too much aromatic alcohol solvent, tends to affect the writing performance during dry-up, while too much glycol ether-based solvent absorbs too much water The film becomes softer and the ink dripping performance and the ink stability over time tend to be affected. Therefore, considering the balance between the writing performance at the time of dry-up and the stability of ink over time, when the content of the aromatic alcohol solvent is A and the content of the glycol ether solvent is B, 1≦A/B≦10 Is preferable, and from the further consideration, 1≦A/B≦5 is preferable.

Furthermore, it is preferable to use an organic amine in the ink composition for an oil-based ballpoint pen of the present invention for the purpose of neutralizing a phosphate ester type surfactant and the like. Examples of the organic amine include oxyethylene alkylamine, polyoxyethylene alkylamine and the like, and alkylamines such as laurylamine, stearylamine, distearylamine, dimethyllaurylamine, dimethylstearylamine and dimethyloctylamine. You may use these individually or in mixture of 2 or more types.

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). If it exceeds 300, since the reactivity is strong and it easily reacts with other components in the ink, the stability with time of the ink tends to be poor. Further, if the total amine value is less than 70, the neutralization with respect to the phosphoric acid ester-based surfactant becomes insufficient, and the ink stability over time tends to be affected. The adsorptivity is likely to be poor and it is difficult to obtain lubrication performance. In consideration of the ink stability over time and the lubricity as described above, the range of 150 to 300 (mgKOH/g) is preferable, and a salt-forming dye of the alkylbenzene sulfonic acid and the triarylmethane-based basic dye is used. From the viewpoint of stability, 200 to 300 (mgKOH/g) is preferable, and from the most consideration, 230 to 270 (mgKOH/g) is preferable. The total amine value indicates the total amount of primary, secondary, and tertiary amines, and is expressed in mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize 1 g of the sample.

Specific examples of oxyethylene alkylamines and polyoxyethylene alkylamines include Nymeen L-201 (total amine value: 232-246, secondary amine) and L-202 (total amine value: 192-212, 3). Primary amine), L-207 (total amine value: 107 to 119, tertiary amine), S-202 (total amine value: 152 to 166, tertiary amine), S-204 (total amine value: 120) -134, tertiary amine), S-210 (total amine value: 75-85, tertiary amine), DT-208 (total amine value: 146-180, tertiary amine) (NOF Corporation) Manufactured) and the like. Specific examples of the alkylamine include Farmin 80 (total amine value: 204 to 210, primary amine), Farmin D86 (total amine value: 110 to 119, secondary amine), Farmin DM2098 (total amine value: 254). ˜265, tertiary amine), Pharmin DM8680 (total amine value: 186-197, tertiary amine) (Kao Corporation) and the like. You may use these individually or in mixture of 2 or more types.

In consideration of lubricity and stability over time, the content of the organic amine is preferably 0.1 to 10.0% by mass, more preferably 0.5 to 5.0% by mass, based on the total amount of the ink composition. Is.

Further, when the total amine value of the organic amine is X and the acid value of the phosphate ester-based 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 the ions of the ball material made of metals and the chip body, and This is because it is likely to cause writing failure. Considering the above reason, 0.1≦Y/X≦1.0 is preferable, and further considering, 0.2≦Y/X≦0.8 is most preferable.

Regarding the colorant used in the present invention, other than the salt-forming dye of the azo skeleton acidic dye and the basic dye, a colorant which is soluble and stable between the azo skeleton acidic dye, the basic dye and the organic solvent. Any (dye, pigment) may be used. As for dyes, oil-soluble dyes, acid dyes, basic dyes, metal-containing dyes, direct dyes, and various salt-forming type dyes thereof, such as salt-forming dyes of acid dyes and basic dyes, organic acids and bases A salt-forming dye with an organic dye, a salt-forming dye with an acid dye and an organic amine, etc. 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, when a dye is used, it is easy to obtain ink aging stability with the salt-forming dye of the azo skeleton acidic dye and basic dye, and it is easy to obtain a deep fresh handwriting, while a pigment is used to disperse the pigment. In order to obtain stability, there are problems such as selection of a pigment dispersant and cost problems. Therefore, it is preferable to use only a dye as a colorant. Furthermore, among the dyes, when a salt-forming dye of an organic acid and a basic dye is used, the salt-forming dye of the azo skeleton acidic dye and the basic dye, polyvinyl butyral resin, and aromatic alcohol are mutually dissolved. It is preferable that it is stable and easily retains stability over a long period of time. Considering stability over a longer period of time, it is preferable to use a salt-forming dye of an alkylbenzene acid and a basic dye in combination.

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

The arithmetic mean roughness (Ra) of the ball surface used in the present invention is preferably 0.1 to 15 nm. This is because if the arithmetic average roughness (Ra) is less than 0.1 nm, it is difficult to deposit ink on the ball surface, it is difficult to obtain thick handwriting during writing, line strokes are easily generated in the handwriting, and the arithmetic average is When the roughness (Ra) exceeds 15 nm, the ball surface is too rough and the rotation resistance between the ball and the ball seat is large, so the writing quality is likely to be poor, and the writing performance such as scratches, line skips, and line unevenness in the handwriting This is because it is easy to affect. In particular, when the polyvinyl butyral resin has a high average degree of polymerization of 1200 to 2000, the cohesive force of the ink tends to be high, so that the arithmetic average roughness (Ra) on the ball surface is 1 to 15 nm. It is more preferable because the ink can be deposited easily. Taking this into consideration, 3 to 13 nm is preferable, and 3 to 10 nm is more preferable.
The surface roughness can be measured by (model name SPI3800N manufactured by Seiko Epson Corporation).

In addition, the material used for the balls is not particularly limited, but a cemented carbide ball containing tungsten carbide as a main component, a metal ball such as stainless steel, and a ceramic such as silicon carbide, silicon nitride, alumina, silica, and zirconia. Examples include balls and ruby balls. A ceramic ball is preferable in consideration of writing quality, wear of the ball seat, and stability over time.

The ball-pen tip materials include metal materials such as stainless steel, nickel silver, brass (brass), aluminum bronze, and aluminum, and resin materials such as polycarbonate, polyacetal, and ABS. In consideration of the properties, a nickel-white chip body is preferable, and in consideration of wear of the ball seat 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 used from the viewpoint of chemical resistance, moisture permeability, air permeability and the like. In that respect, it is conventionally preferable to use polypropylene as a material. However, when the salt-forming dye of the azo skeleton acidic dye and the basic dye used in the present invention is used, it has a very strong affinity with the polypropylene ink container, and when the ink moves in the ink container, the ink Easily adheres to the inner wall, making it difficult to know the amount of ink remaining. In particular, when the polyvinyl butyral resin and the salt-forming dye are used in combination, they tend to adhere, and therefore, 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 by applying silicone to the inner wall of the ink storage cylinder, the polypropylene, which is the material of the storage cylinder, does not directly contact the ink, but maintains the relationship with the silicone in the middle, and the ink 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, methylphenyl silicone, methylhydrogen silicone, alkylaralkyl silicone, polyether silicone, and high fatty acid ester fatty acid silicone. Among them, they have excellent anti-adhesion properties and are non-reactive. From the viewpoint of stability with respect to oil-based ink components, alkyl aralkyl silicone is preferable. The most effective method of coating is to coat the inner wall uniformly at the time of extrusion molding.

Next, the present invention will be described with reference to examples.
The oil-based ballpoint pen ink composition of Example 1 contains 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, and oxyethylene alkyl as an organic amine. Polyvinylpyrrolidone was adopted as the amine and the spinnability imparting resin, a predetermined amount of this was weighed, heated to 60° C., and completely dissolved using a Disper stirrer to obtain an oil-based ballpoint pen ink composition. The specific compounding amount is as follows.
Ink viscosity of Example 1 was measured at a shear rate of 5 sec ^-1 (rotation speed 2.5 rpm) in an environment of 20°C using a viscometer RVDVII+Pro CP-52 spindle manufactured by Brookfield Co., Ltd. Then, the ink viscosity was 23000 mPa·s.
Further, in Example 1, where X is the total amine value of the organic amine and Y is the acid value of the phosphate ester-based surfactant, Y/X=0.32 to 0.39. ..
Further, the ink consumption amount (M) per 100 m in Example 1 was 45 mg/100 m and M/R=64 when a spiral writing test was performed with a ballpoint pen refill having a ball diameter (R) of 0.7 mm. ..

Example 1
Coloring agent (dye, salt forming dye of azo skeleton acidic dye and basic dye) 18.0% by mass
Alcoholic solvent (benzyl alcohol) 53.0% by mass
Glycol ether solvent (ethylene glycol monophenyl ether) 16.5% by mass
Polyvinyl butyral resin (S-REC BH-3, hydroxyl amount: 34 mol%, average degree of polymerization: 1700) 9.0% by mass
Lubricant (phosphate ester type surfactant) 1.0% by mass
Organic amine (oxyethylene alkylamine) 1.0% by mass
Spinnability imparting resin (polyvinylpyrrolidone resin) 0.5% by mass

Examples 2 to 17
As shown in the table, the ink compositions for oil-based ballpoint pens of Ink Formulation Examples 2 to 17 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.
Further, in Examples 2 to 17, when the total amine value of the organic amine is X and the acid value of the phosphate ester surfactant is Y, Y/X=0.2 to 0.8 there were.

Comparative Examples 1-8
As shown in the table, the ink compositions for oil-based ballpoint pens of Comparative Examples 1 to 8 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.

Tests and Evaluations The ink compositions for oil-based ballpoint pens prepared in Examples 1 to 17 and Comparative Examples 1 to 9 were coated with silicone on the inner wall of an ink containing cylinder (made of polypropylene). A ball-point pen tip 4 rotatably holding a ball 3 (φ0.7 mm) having a surface arithmetic average roughness (Ra) of 6 nm is mounted, and the ink 10 for an oil-based ball-point pen of Example 1 is mounted in the ink containing cylinder 2. 0.2 g) was directly accommodated, and the ballpoint pen refill 1 was placed on an oil-based ballpoint pen (trade name: Supergrip) manufactured by Pilot Corporation to produce an oil-based ballpoint pen, and writing paper JIS P3201 was used as a writing test paper. The following tests and evaluations were performed using

Specifically, the ball-point pen tip 4 is formed by cutting a stainless steel wire rod 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 circulation groove 8 extending to the bottom, a ball seat 9 having a substantially arc surface shape is formed on the bottom wall of the ball holding chamber 6. Thereafter, the balls 3 made of silicon nitride are placed on the ball seat 9 and the tip end portion 5 of the chip is caulked inward.

Further, the ball exit H from the tip of the chip when the ball 3 is mounted 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 present. 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.

Darkness of handwriting: The handwriting written by handwriting was observed.
Thick and clear handwriting...◎
Thick handwriting...○
Handwriting with sufficient depth for practical use... △
Light handwriting...×

Ink aging test: Each oil-based ink composition for ballpoint pens was placed in a close-opening/closing glass test tube having a diameter of 15 mm, allowed to stand at room temperature for 1 month, and an appropriate amount was collected, and the ink was observed under a microscope.
Good dissolution stability and no separation or precipitates ・・・◎
Separation and a small amount of precipitates were generated, but they were good.
Separation and precipitates were generated, but there is no problem in practical use... △
Separation or precipitates that cannot be made into ink or cause writing defects... ×

Ink dripping performance test: The ink was allowed to stand for 7 days with the pen tip facing downward in an environment of 30° C. and 85% RH, and ink leakage from the tip of the tip was confirmed.
There is no ink drop on the tip of the tip ・・・◎
Ink droplets at the tip of the tip are within 1/4 of the taper portion.
Ink droplets at the tip of the tip are 1/4 or more and 1/2 or less of the taper portion... △
Ink droplets at the tip of the tip are 1/2 or more of the taper portion ・・・ ×

Writing quality: Sensory test by handwriting was performed and evaluated.
Very smooth... ◎
What is smooth・・・○
Those with a level of smoothness that is practically no problem... △
Heavy things...×

In Examples 1 to 17, good performances were obtained in terms of handwriting density, ink aging test, ink dripping test, and writing quality.

In Comparative Examples 1 to 3, since the salt-forming dye basic dye of the azo skeleton acidic dye and the basic dye was not used, the dissolution was not stable and the separation occurred.

In Comparative Example 4, since the basic dye was used alone, it was not stable in dissolution and separated.

In Comparative Examples 5 and 7, since M/R<40, the depth of handwriting was not sufficient.

In Comparative Examples 6 and 8, since M/R>100, the ink dripping performance was poor, and crying fluffing also occurred.

Comparative Example 9
Although not shown in the table, in the ball-point pens of Examples and Comparative Examples, when the writing test is performed, the ink moves in the ink containing cylinder as the ink is consumed. Since it is applied to the inner wall of polypropylene), the ink does not adhere to the inner wall of the ink container, so that the ink remaining amount can be clearly confirmed. On the other hand, as Comparative Example 9, a writing test was performed using the ink composition for an oil-based ballpoint pen of Example 1 with a ballpoint pen not coated on the inner wall of the ink container (made of polypropylene) with silicone. The ink remained on the surface, and the amount of ink remaining was unknown.

In addition, when using a retractable oil-based ballpoint pen such as a knock-type oil-based ballpoint pen or a rotary feeding type oil-based ballpoint pen, the ink dripping performance is one of the most important performances. It is effective to use an oil-based ballpoint pen, which is formed and covers the gap between the ball and the tip of the chip to improve the ink dripping performance.

Further, in the present embodiment, for the sake of convenience, an oil-based ballpoint pen containing an oil-based ballpoint pen refill that directly contains the ink composition for an oil-based ballpoint pen is illustrated in the barrel, but the oil-based ballpoint pen of the present invention has a barrel. A direct-packing type oil-based ballpoint pen in which the ink composition for the oil-based ballpoint pen is directly stored in the shaft cylinder may be used as the ink container. Further, in the present embodiment, for convenience, a ball-point pen tip formed by cutting a wire is illustrated, but a ball-point pen tip formed by pressing a pipe material may be used.

Further, in the present embodiment, the caulking angle of the ball-point pen tip is set to 70 degrees, but if the caulking angle is too large, the paper contact angle tends to become small, so 90 degrees or less, preferably 80 degrees or less. preferable. If the caulking angle is 50 degrees or less, the space for accumulating the ink between the ball 9 and the tip edge of the chip tends to be small, and it is difficult to return the ink, and it is difficult to suppress the creeping of the ink. Therefore, the caulking angle is 50 degrees. It is preferable to set the angle to 90 degrees.

In addition, the inner diameter of the ball ejection/ball holding chamber is not particularly limited, but when the ink consumption per 100 m of the oil-based ballpoint pen refill is M (mg) and the ball diameter is R (mm). , 40≦M/R≦100, the ball protrusion 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. %, and the ball seat diameter is preferably 70 to 95% of the ball diameter.

INDUSTRIAL APPLICABILITY The present invention can be used as an oil-based ballpoint pen, and more specifically, it can be widely used as a cap-type, knock-type oil-based ballpoint pen filled with the ink composition for an oil-based ballpoint pen. Furthermore, the present invention is not limited to the ballpoint pen of the embodiment, and may be suitably used for a marking pen, a fountain pen, a sense pen, a plate pen, and the like.

1 Ballpoint pen refill 2 Ink storage cylinder 3 Ball 4 Ballpoint pen tip 5 Tip tip 6 Ball holding chamber 7 Ink flow hole 8 Ink flow groove 9 Ball seat 10 Ink for oily ballpoint pen H Ball ejection α Caulking angle

Claims (6)

At the tip of the ink containing cylinder, a ball-point pen tip that rotatably holds a ball is attached directly or through a chip holder, and at least a colorant, an organic solvent, a phosphate ester-based surfactant is contained in the ink containing cylinder. An oil-based ballpoint pen refill containing an oil-based ink composition for an oil-based ballpoint pen, wherein the colorant is a salt-forming dye of an azo skeleton acidic dye and a basic dye, and 100 m of the oil-based ballpoint pen refill. When the ink consumption per unit is M (mg) and the ball diameter is R (mm), there is a relationship of 40≦M/R≦100, and the ink composition for oil-based ballpoint pens at 20° C. and a shear rate of 5 sec ⁻¹ . An oil-based ballpoint pen refill characterized in that the ink viscosity of the product is 10,000 to 50,000 mPa·s. The oil-based ballpoint pen refill according to claim 1, wherein the azo skeleton acid dye is a diazo skeleton acid dye. The oil-based ballpoint pen refill according to claim 1, wherein the oil-based ballpoint pen ink composition contains a spinnability imparting resin. The oil-based ballpoint pen refill according to any one of claims 1 to 3, wherein the oil-based ballpoint pen ink composition contains a polyvinyl butyral resin. An oil-based ballpoint pen refill according to any one of claims 1 to 4, wherein the inner wall of the ink container of the oil-based ballpoint pen refill is coated with silicone. An oil-based ballpoint pen in which the oil-based ballpoint pen refill according to any one of claims 1 to 5 is disposed in a barrel.

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