JP7007822B2 - Oil-based ink composition for writing tools and writing tools using it - Google Patents

Description

The present invention relates to an oil-based ink composition for writing tools and a writing tool using the same.

Conventionally, oil-based ink compositions for writing instruments that use a pigment as a colorant have excellent light resistance of handwriting, but the drawing density tends to be thin with the pigment alone, and it is difficult to form a handwriting with a desired color tone, and the hue is also high. There is a problem that it is difficult to adjust.
On the other hand, since the ink using a dye as a colorant has excellent color development property, an ink having a good color tone can be obtained, but the light resistance of the handwriting is inferior to that of the pigment, and the color fading is remarkable. This is because the dye undergoes a chemical reaction and is decomposed by irradiation with light.

In order to solve these problems, many oil-based ink compositions for writing tools have been proposed, which contain a gold-containing dye having a heavy metal such as chromium, cobalt, and copper in the dye skeleton in order to obtain good light resistance of handwriting. ..

Examples of the oil-based ink composition for writing instruments using such a gold-containing dye include JP-A-2002-3771 "Ink Composition for Oil-based Ballpoint Pens" and JP-A-2007-2163 "Oil-based Ink Composition for Writing Instruments and Its". It is disclosed in "Writing Instruments with Built-in" and the like.

"Japanese Patent Laid-Open No. 2002-3771" "Japanese Patent Laid-Open No. 2007-2163"

However, in the gold-containing dye as in Patent Document 1, chromium and copper are contained in the dye, and as the gold-containing dye as in Patent Document 2, C.I. I. When Solvent Black 29 is used, C.I. I. Since the solvent black 29 contains chromium in the dye, the ink using the solvent black 29 is concerned about the influence on the safety and improvement is desired.
Further, as a conventional ultraviolet absorber, there are titanium oxide, zinc oxide and the like as an inorganic ultraviolet absorber. These have excellent light resistance of handwriting to some extent, but because the ultraviolet absorption band is narrow, the adaptive absorption wavelength The range of is narrow and not enough. Further, since the inorganic ultraviolet absorber itself is colored, it affects the color tone of the ink and has a large specific gravity. Therefore, it is necessary to consider the dispersion stability in the ink.

An object of the present invention is to obtain an oil-based ink composition for writing tools, which improves the light resistance of handwriting and has good ink stability over time, and a writing tool using the same.

３．前記ヒドロキシフェニルベンゾトリアゾール化合物の含有量が、インキ組成物全量に対して、０．１～１５．０質量％であることを特徴とする第１項または第２項に記載の筆記具用油性インキ組成物。
４．前記酸化防止剤が、ヒンダードアミン化合物であることを特徴とする第１項ないし第３項のいずれか１項に記載の筆記具用油性インキ組成物。
５．前記有機溶剤がアルコ－ル溶剤またはグリコールエーテル溶剤であることを特徴とする第１項ないし第４項のいずれか１項に記載の筆記具用油性インキ組成物。
６．前記筆記具用油性インキ組成物に、さらにポリビニルブチラール樹脂またはケトン樹脂を含んでなることを特徴とする第１項ないし第５項のいずれか１項に記載の筆記具用油性インキ組成物。
７．第１項ないし第６項のいずれか１項に記載の筆記具用油性インキ組成物を収容してなることを特徴とする筆記具。」とする。 The present invention is an oil-based ink composition for writing utensils, which comprises "1. a colorant, an organic solvent, a hydroxyphenylbenzotriazole compound, and an antioxidant" in order to solve the above problems.
2. 2. The oil-based ink composition for writing tools according to Item 1, wherein the hydroxyphenylbenzotriazole compound has the general formula (Chemical Formula 1).

3. 3. The oil-based ink composition for writing tools according to item 1 or 2, wherein the content of the hydroxyphenylbenzotriazole compound is 0.1 to 15.0% by mass with respect to the total amount of the ink composition. thing.
4. The oil-based ink composition for writing tools according to any one of Items 1 to 3, wherein the antioxidant is a hindered amine compound.
5. The oil-based ink composition for writing tools according to any one of Items 1 to 4, wherein the organic solvent is an alcohol solvent or a glycol ether solvent.
6. The oil-based ink composition for writing tools according to any one of Items 1 to 5, wherein the oil-based ink composition for writing tools further contains a polyvinyl butyral resin or a ketone resin.
7. A writing tool comprising the oil-based ink composition for writing tools according to any one of paragraphs 1 to 6. ".

INDUSTRIAL APPLICABILITY According to the present invention, it was possible to obtain an oil-based ink composition for writing instruments and a writing instrument using the same, which improve the light resistance of handwriting and have good stability over time of ink by absorbing ultraviolet rays.

Hereinafter, embodiments of the present invention will be described in detail. In addition, in this specification, "part", "%", "ratio", etc. indicating a composition are based on mass unless otherwise specified.

A feature of the present invention is to prepare an oil-based ink composition for writing utensils, which comprises a colorant, an organic solvent, a hydroxyphenylbenzotriazole compound, and an antioxidant. By containing the hydroxyphenylbenzotriazole compound, the light resistance of the handwriting is improved, and the stability over time in the ink is improved, so that the effect of the present invention can be stably obtained.

(Hydroxyphenylbenzotriazole compound)
The hydroxyphenylbenzotriazole compound used in the present invention is a compound having a benzotriazole skeleton having hydroxyphenyl, and absorbs ultraviolet rays having a wavelength of less than 400 nm and converts them into heat to absorb the ultraviolet rays. It is possible to improve the light resistance of the compound and to exist stably even in the ink. Furthermore, by having an aromatic ring, a lubricating effect can be obtained at the tip of the writing, so ink can be ejected smoothly, and by increasing the amount of ink consumed, it works favorably on the light resistance of the handwriting, and also causes blurring of the handwriting. It is easy to suppress and improve the writing ability, and it is especially effective when using a ballpoint pen.

Examples of the hydroxyphenylbenzotriazole compound include 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (formation 1) and 2- (2H-benzotriazole-2-yl) -6- (1-). Methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (chemical 2), 5% 2-methoxy-1-methylethyl acetate 95% benzenepropanoic acid, 3- (2H) -Benzotriazole-2-yl) -5- (1,1-1,1-dimethylethyl) -4-hydroxy, 2- (2H-benzotriazole-2-yl) -4,6-bis (1-methyl) Reaction product of -1-phenylethyl) phenol, methyl 3-3 (3-2H-benzotriazole-2-yl) -5-t-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 (BASF Japan Co., Ltd.) ), (2- (2'-Hydroxy-5'-t-octylphenyl) benzotriazole and the like. Specifically, "TINUVIN PS", "TINUVIN 928", "TINUVIN 99-2", " Examples thereof include "TINUVIN 900", "TINUVIN 384-2", "TINUVIN 1130" (manufactured by BASF Japan Co., Ltd.), and "SEESORB709" (manufactured by Shiraishi Calcium Co., Ltd.).

Among the hydroxyphenylbenzotriazole compounds, the strong absorption of ultraviolet rays makes it easy to improve the light resistance of brush strokes, and further improves the compatibility with organic solvents, colorants, and resins in ink. Considering that it has a long-term effect, it is preferable to use the general formula (Chemical formula 1).

The content of the hydroxyphenylbenzotriazole compound is more preferably 0.1 to 20.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, it is difficult to obtain the desired ultraviolet absorption capacity, it is difficult to obtain the light resistance of the handwriting, and if it exceeds 20.0% by mass, the ink aging tends to be unstable. In consideration of this tendency, 1.0 to 12.0% by mass is preferable, and more consideration is given, 3.0 to 10.0% by mass is preferable.

(Antioxidant)
In the present invention, it is preferable to use an antioxidant in consideration of further improving the light resistance of the handwriting. This is because radicals such as oxygen are generated by the cleavage of chemical species photoexcited by ultraviolet rays, which is one of the causes of deterioration of the dye. This is because it can capture and inactivate active oxygen. In the present invention, by using a hydroxyphenylbenzotriazole compound capable of cutting the cause of these series of reactions in combination with an antioxidant, even if the hydroxyphenylbenzotriazole compound cannot completely absorb ultraviolet rays, it is an antioxidant. Therefore, it is possible to further improve the light resistance of the brush stroke by the above-mentioned chemical effect.

Examples of the antioxidant include hindered amine compounds and benzoate compounds, but it is preferable to use hindered amine compounds in consideration of improving the light resistance of handwriting by capturing oxygen radicals and the like. Further, since it is easy to capture oxygen radicals and the like for a long period of time, it is preferable to contain a hindered amine compound having a piperidine structure. The piperidine structure is a heterocyclic amine having a 6-membered ring structure, has a structure in which one carbon atom of cyclohexane is replaced with a nitrogen atom, and has any structure as long as it has a saturated 6-membered ring amine structure. However, it also includes those in which a part of the piperidine structure is substituted with a substituent.

Specific examples of the antioxidant include bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) ester, 1,1-dimethylethylhydroperoxide and octane. Reaction product (chemical 2), a mixture of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate ( 3), bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, etc. Can be mentioned. Specifically, "TINUVIN 111FDL", "TINUVIN 123", "TINUVIN 144", "TINUVIN 292", "TINUVIN 479" (manufactured by BASF Japan Ltd.), "KEMISORB112", "KEMISORB113", "KEMISORB113", " Examples thereof include "KEMISTAB29", "KEMISTAB62", "KEMISTAB77", and "KEMISTAB94" (manufactured by Chemipro Kasei Co., Ltd.).

Further, among the hindered amine compounds, the general formulas (Chemical formula 2) and (Chemical formula 3) having a piperidine structure should be used in consideration of the fact that they have a strong ability to capture oxygen radicals and the like and further improve the light resistance of handwriting. It is preferable to use the general formula (Chemical Formula 2) in consideration of the fact that the long-term effect of the present invention can be obtained by improving the stability over time in the ink.

Further, the content of the antioxidant is more preferably 0.1 to 10.0% by mass with respect to the total amount of the ink composition. If it is less than 0.1% by mass, it is difficult to obtain the desired radical capture effect, and it tends to be difficult to obtain the light resistance of the brush stroke. If it exceeds 10.0% by mass, the ink aging becomes unstable. This is because it tends to be easy, and considering the tendency, 0.5 to 8.0% by mass is preferable, and more considering it, 1.0 to 5.0% by mass is preferable.

(Colorant)
The colorant used in the present invention is not particularly limited to dyes, pigments and the like, and can be appropriately selected and used, and dyes and pigments may be used in combination. The present invention is effective when a dye is used as the colorant because the light resistance of the handwriting tends to be inferior.
Dyes include oil-soluble dyes, acidic dyes, basic dyes, gold-containing dyes, and various salt-forming type dyes such as salt-forming dyes of acidic dyes and basic dyes, basic dyes and organic acids. Types of salt-forming dyes such as salt-forming dyes with and salt-forming dyes with acidic dyes and organic amines can be mentioned. In addition, considering the light resistance, the higher the dye concentration, the better the light resistance. The salt-forming dyes of basic dyes and organic acids, and the salt-forming dyes of acidic dyes and organic amines are oils. Compared with soluble dyes, acidic dyes and basic dyes, the dye concentration is lower, so it is effective to use a hydroxyphenylbenzotriazole compound as in the present invention.

Further, as the colorant, it is preferable to use at least a salt-forming dye in consideration of the aging stability of the ink due to the compatibility by using the hydroxyphenylbenzotriazole compound, and further, the aging due to the stable salt-forming bond. Considering the stability, it is preferable to use a salt-forming dye of a basic dye and an organic acid, a salt-forming dye of an acidic dye with a basic dye, and a salt-forming dye of an acidic dye and an organic amine. Considering more, salt-forming dyes of basic dyes and organic acids are preferable. In particular, considering long-term stability in ink, a salt-forming dye using alkylbenzene sulfonic acid as the organic acid is preferable.

Specifically, regarding dyes, Bali First Black 1802, Bali First Black 1805, Bali First Black 1807, Bali First Violet 1701, Bali First Violet 1704, Bali First Violet 1705, Bali First Blue 1601, Bali First Blue 1605, Bali First Blue 1613, Bali First Blue 1621, Bali First Blue 1631, Bali First Red 1320, Bali First Red 1355, Bali First Red 1360, Bali First Yellow 1101, Bali First Yellow 1151, Nigrosin Base EXBP, Nigrosin Base EX, BASE OF BASIC DYES ROB-B, BASE OF BASIC DYES RO6GB, BASE OF BASIC DYES VPB-B, BASE OF BASIC DYES VB-B, BASE OF BASIC DYES MVB-3 (all manufactured by Orient Chemical Industry Co., Ltd.), Eisenspiron Black GMH-Special, Eisenspiron Violet C-RH, Eisenspiron Blue GNH, Eisenspiron Blue 2BNH, Eisenspiron Blue C-RH, Eisenspiron Red C-GH, Eisenspiron Red C-BH, Eisenspiron Yellow C-GNH, Eisenspiron Yellow C-2GH, S.A. P. T. Blue 111, S.A. P. T. Blue GLSH-Special, S.M. P. T. Red 533, S.M. P. T. Orange 6, S.M. B. N. Violet 510, S.A. B. N. Yellow 530, S.A. R. C-BH (above, manufactured by Hodogaya Chemical Co., Ltd.) and the like can be mentioned.

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

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

When the content of the hydroxyphenylbenzotriazole compound with respect to the total amount of the ink composition is A and the content of the colorant with respect to the total amount of the ink composition is B, 0.01 ≦ A / The relationship of B ≦ 2 is preferable. In the above range, the amount of the hydroxyphenylbenzotriazole compound has a sufficient ability to absorb ultraviolet rays with respect to the amount of the colorant, and the light resistance of the writing is improved. It is easy to improve, and if more considered, the relationship of 0.1 ≦ A / B ≦ 1 is preferable.

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

Among these organic solvents, it is preferable to use a water-insoluble organic solvent in consideration of the solubility with the hydroxyphenylbenzotriazole compound, and among them, in consideration of the dissolution stability, an alcohol solvent or a glycol ether. It is preferable to use a solvent, and an alcohol solvent or a glycol ether solvent having an aromatic ring is more preferable because it tends to improve the lubricity.

Further, the content of the organic solvent is preferably 10.0 to 90.0% by mass with respect to the total amount of the ink composition in consideration of improving the solubility, the dryness of handwriting, the bleeding and the like. It is preferably 20.0 to 90.0% by mass, more preferably 40.0 to 70.0% by mass.

(resin)
Further, in order to further improve the suppression of ink leakage, it is preferable to use a resin as an ink viscosity adjusting agent. As the resin, polyvinyl butyral resin, ketone resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, terpene resin, etc. Examples thereof include alkyd resin, phenoxy resin, and polyvinyl acetate resin, and among them, polyvinyl butyral resin or ketone resin is preferably contained in consideration of stability in ink. Further, it is preferable to use polyvinyl butyral resin, which is presumed to be because the resin film formed in the handwriting easily blocks ultraviolet rays and further improves the light resistance of the handwriting.

Further, with respect to the polyvinyl butyral resin, it is easy to form a lubricating layer capable of obtaining a higher lubricating effect. Therefore, in the case of a ballpoint pen, an elastic ink layer is always formed between the ball and the ball seat, making it difficult to make direct contact and improving the writing quality, so that ink can be ejected smoothly and ink consumption. By increasing the number of inks, the light resistance of the handwriting works advantageously, and the handwriting blurring is also suppressed, so that the writing performance is easily improved. Further, it is preferable to use the polyvinyl butyral resin because the film formed makes it easier to improve ink leakage.
Here, the polyvinyl butyral resin is obtained by reacting polyvinyl alcohol (PVA) with butyraldehyde (BA), and has a structure having a butyral group, an acetyl group, and a hydroxyl group.

The polyvinyl butyral resin preferably has a hydroxyl group content of 25 mol% or more. This is because polyvinyl butyral resin with a hydroxyl group content of less than 25 mol does not have sufficient solubility in organic solvents, and it is difficult to obtain sufficient lubrication effect and ink leakage suppression effect. This is because it is preferable to use a polyvinyl butyral resin having a hydroxyl group content of 25 mol% or more in consideration of the property. In addition, the polyvinyl butyral resin having a hydroxyl group content of 30 mol% or more easily improves the writing quality, so that the ink can be ejected smoothly, and by increasing the amount of ink consumed, the light resistance of the handwriting is advantageous, and the handwriting blurring is further achieved. It is preferable because it suppresses the amount of ink and easily improves the writing ability. This is because at the time of writing, frictional heat is generated by the rotation of the ball, which warms the ink at the tip of the chip and raises the temperature of the ink, but the polyvinyl butyral resin is different from other resins. Even if the ink temperature rises, it has the property of making it difficult to lower the ink viscosity, and it always forms an elastic ink layer between the ball and the ball seat, making it difficult to make direct contact, improving the writing quality. It tends to be easy. In particular, ballpoint pens are effective for writing instruments because they often write with high writing pressure. Further, when a polyvinyl butyral resin having a hydroxyl group content of more than 40 mol% is used, the amount of moisture absorption tends to increase and the stability with time with the ink component tends to be affected. Therefore, a polyvinyl butyral resin having a hydroxyl group content of 40 mol% or less is preferable. Therefore, a polyvinyl butyral resin having a hydroxyl group content of 30 to 40 mol% is preferable, and a hydroxyl group content of 30 to 36 mol% is more preferable.
The amount of hydroxyl groups (mol%) of the polyvinyl butyral resin includes hydroxyl groups (mol%) with respect to the total mol amount of butyral groups (mol%), acetyl groups (mol%), and hydroxyl groups (mol%). It shows the rate.

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

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

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

Specifically, the polyvinyl butyral resin is a trade name manufactured by Sekisui Chemical Industry Co., Ltd .; Eslek BH-3 (hydroxyl amount: 34 mol%, average degree of polymerization: 1700), BH-6 (hydroxyl amount: 30 mol%). , Average degree of polymerization: 1300), BX-1 (hydroxyl amount: 33 ± 3 mol%, average degree of polymerization: 1700), BX-5 (hydroxyl amount: 33 ± 3 mol%, average degree of polymerization: 2400), BM -1 (Amount of hydroxyl group: 34 mol%, average degree of polymerization: 650), BM-2 (amount of hydroxyl group: 31 mol%, average degree of polymerization: 800), BM-5 (amount of hydroxyl group: 34 mol%, average degree of polymerization: 850) ), BL-1 (hydroxyl amount: 36 mol%, average degree of polymerization: 300), BL-1H (hydroxyl amount: 30 mol%), BL-2 (hydroxyl amount: 36 mol%, average degree of polymerization: 450), etc. Can be mentioned. These may be used alone or in admixture of two or more.

As the resin other than the polyvinyl butyral resin and the ketone resin, a spinnability-imparting agent may be appropriately used. In particular, it is preferable to contain polyvinylpyrrolidone resin because it is easy to improve the binding property of the ink and suppress the generation of excess ink at the tip of the chip by blending the polyvinylpyrrolidone resin.

(Surfactant)
In the present invention, it is preferable to use a surfactant in consideration of lubricity and improvement of writing performance when the tip tip is dried while the tip tip is left in the atmosphere. This is because when a surfactant is used, the formed film tends to be softened, the writing performance can be improved, and the lubricity is also improved, so that the ink can be ejected smoothly and the ink consumption is increased. Therefore, it is easy to work favorably on the light resistance of handwriting. Examples of the surfactant include fatty acids, fatty acid esters, silicone-based surfactants, fluorine-based surfactants, and phosphate ester-based surfactants. Among them, in consideration of the above effects, it is preferable to use a fatty acid or a phosphoric acid ester-based surfactant, and more in consideration, a phosphoric acid ester-based surfactant is preferable.

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

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

In addition, as a viscosity modifier, a pseudoplastic-imparting agent such as fatty acid amide, hydrogenated castor oil, or cellulose derivative, an amine having ethylene oxide, an organic amine such as an aliphatic amine, a colorant stabilizer, a plasticizer, etc. A chelating agent, water or the like may be used as appropriate. These may be used alone or in combination of two or more.

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

The arithmetic mean roughness (Ra) of the ball surface of the ballpoint pen tip used in the present invention is preferably 0.1 to 12 nm. This is because when the arithmetic mean roughness (Ra) is 0.1 to 12 nm, the ink is sufficiently easily placed on the ball surface, the ink can be ejected smoothly, and the ink consumption is increased, so that a dark handwriting can be obtained. This is because it makes it easier to work favorably on the light resistance of handwriting. Further, considering the above effects, the arithmetic mean roughness (Ra) is preferably 0.1 to 10 nm, more preferably 2 to 8 nm. The surface roughness can be measured by (model name SPI3800N manufactured by Seiko Epson Corporation).

The material used for the balls is not particularly limited, but is limited to cemented carbide balls containing tungsten carbide as a main component, metal balls such as stainless steel, and ceramics such as silicon carbide, silicon nitride, alumina, silica, and zirconia. Examples include balls and ruby balls.

Examples of the material of the ball pen tip include metal materials such as stainless steel, white, brass (brass), aluminum bronze, and aluminum, and resin materials such as polycarbonate, polyacetal, and ABS.

Next, the present invention will be described with reference to examples.
The oil-based ink composition for writing tools of Example 1 is a salt-forming dye, an organic solvent, a hydroxyphenylbenzotriazole compound, an antioxidant, an organic amine, polyvinyl butyral, a phosphate ester-based surfactant, and polyvinyl as a spinnability-imparting resin. Pyrrolidone was adopted, weighed it in a predetermined amount, heated to 60 ° C., and then completely dissolved using a disper stirrer to obtain an oil-based ink composition for writing utensils. The specific blending amount is as follows.
The ink viscosity of Example 1 was measured at a shear rate of 5 sec ^-1 (rotation speed 2.5 rpm) in an environment of 20 ° C. using a viscometer Viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield Co., Ltd. The ink viscosity was 20000 mPa · s.

Example 1
Colorant (salt dye made from acid dye and basic dye) 10.0% by mass
Colorant (salt-forming dye of basic dye and organic acid) 2.0% by mass
Alcohol solvent (benzyl alcohol) 40.5% by mass
Glycol ether solvent (ethylene glycol monophenyl ether) 15.0% by mass
Hydroxyphenylbenzotriazole compound (Chemical formula 1) 5.0% by mass
Antioxidant (Chemical Formula 2) 5.0% by mass
Surfactant 1.0% by mass
Organic amine 1.0% by mass
Polyvinyl butyral 20.0% by mass
Spinning property imparting resin (polyvinylpyrrolidone resin) 0.5% by mass

Examples 2-9
As shown in the table, ink was blended in the same procedure as in Example 1 except that each component was changed to obtain an oil-based ink composition for writing tools of Examples 2 to 2. The table shows the measurement and evaluation results.

Comparative Examples 1 to 4
As shown in the table, oil-based ink compositions for writing tools of Comparative Examples 1 to 4 were obtained in the same procedure as in Example 1 except that each component was changed. The table shows the measurement and evaluation results.

Test and Evaluation A ballpoint pen in which a ball (φ0.7 mm) is rotatably held at the tip of an ink storage cylinder (made of polypropylene) of the oil-based ink composition for writing tools produced in Examples 1 to 9 and Comparative Examples 1 to 4. An oil-based ballpoint pen manufactured by Pilot Corporation Co., Ltd. (trade name: Super) is used to directly accommodate the oil-based ink composition (0.2 g) for writing tools of Example 1 in the ink-containing cylinder while mounting the chip. An oil-based ballpoint pen was prepared by arranging it on a grip (registered trademark)), and the following tests and evaluations were performed using the writing paper JIS P3201 as the writing test paper.

Light resistance test: A spiral writing test was performed on JIS P3201 writing paper A at a writing angle of 70 ° and a writing load of 100 g at a writing speed of 4 m / min, and after leaving it for 1 hour, the xenon fade meter X15F (Suga). Using a testing machine (manufactured by Testing Machine Co., Ltd.), the blue scale was irradiated until it faded to the third grade, and the handwriting was observed.
Does not fade or slightly fades ... ◎
The color fades, but there is no problem in practical use ... ○
Fading is noticeable and it is a practical problem ... ×

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

Writing taste: A handwritten sensory test was conducted and evaluated.
Smooth ... ○
Smoothness at a level that does not cause any problems in practical use ... △
Heavy things ... ×

In Examples 1 to 9, good performance was obtained in both the light resistance test of the handwriting and the ink aging test, and the writing taste was smooth (evaluation: ◯) and good.

In Comparative Examples 1 and 2, since the hydroxyphenylbenzotriazole compound was not used, the color faded in the light resistance test of the handwriting.
In Comparative Examples 3 to 4, since a tetrazole compound (a 5-membered heterocyclic compound in which the ring consists of 1 carbon and 4 nitrogens) was used, the color faded in the light resistance test of the handwriting.

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

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

Claims (7)

The hydroxyphenylbenzotriazole compound contains a colorant, an organic solvent, a hydroxyphenylbenzotriazole compound, and an antioxidant, and the hydroxyphenylbenzotriazole compound has the general formula (Chemical formula 1), and further, a polyvinyl butyral resin having a hydroxyl group content of 30 mol% or more, HLB. An oil-based ink composition for writing tools, which comprises a surfactant having a value of 6 to 14.

The oil-based ink composition for writing tools according to claim 1, wherein the content of the hydroxyphenylbenzotriazole compound is 0.1 to 15.0% by mass with respect to the total amount of the ink composition. The oil-based ink composition for writing tools according to claim 1 or 2 , wherein the antioxidant is a hindered amine compound. The oil-based ink composition for writing tools according to any one of claims 1 to 3 , wherein the organic solvent is an alcohol solvent or a glycol ether solvent. The oil-based ink composition for writing tools according to any one of claims 1 to 4 , wherein the colorant is a salt-forming dye. The oil-based ink composition for writing tools according to any one of claims 1 to 5 , wherein the ink viscosity is 3000 to 30,000 mPa · s at 20 ° C. and a shear rate of 5 sec ^-1 . A writing tool comprising the oil-based ink composition for writing tools according to any one of claims 1 to 6 .