JP6859213B2 - Ink composition for writing instruments and writing instruments using it - Google Patents

Description

The present invention relates to an ink composition for a writing instrument and a writing instrument using the same.

Conventionally, in the ink composition for writing tools, in the case of a ballpoint pen, ink leaks from the gap at the tip of the writing (ink leaks from the gap between the ball and the tip of the tip), and in the case of a marking pen, felt-tip pen, etc., from the tip of the writing. In order to suppress ink leakage, a solvent having a steam pressure of 0.001 mmHg or more at 25 ° C. is used, silica or felt-tip penphenol resin is used as an ink leakage inhibitor, or an ink gelling agent is used to obtain ink viscosity. A technique for ink compositions for felt-tip pens with a high setting has been proposed.

As a technique using an alcohol, a polyhydric alcohol, or a glycol ether solvent having a steam pressure of 0.001 mmHg or more at 25 ° C. as such an ink composition for writing instruments, Japanese Patent Application Laid-Open No. 2004-107591 "Oil property for writing instruments". As a technique using an "ink composition" or an ink leakage inhibitor, JP-A-10-195365 "Oil-based ink for ballpoint pens" using silica having a primary average particle diameter of 7 to 40 nm, and an OH value of 150 or more. A technique using a terpene phenol resin is disclosed in Japanese Patent Application Laid-Open No. 2007-126528 “Oil-based ink for ballpoint pens”.

"Japanese Patent Laid-Open No. 2004-107591" "Japanese Patent Laid-Open No. 10-195365" "Japanese Patent Laid-Open No. 2007-126528"

However, although Patent Document 1 has an effect of suppressing ink leakage to some extent, when the ink viscosity is lowered, ink leakage cannot be sufficiently suppressed only by the solvent used in Patent Document 1. Further, in Patent Document 2, silica having a primary average particle diameter of 7 to 40 nm has a small particle size and a large specific gravity of silica, so that the dispersion stability in oil-based ink is inferior. In the terpenphenol resin having a value of 150 or more, since the OH value is high, the solubility in the oil-based ink is poor, and sufficient effects cannot be exhibited.

An object of the present invention is to obtain an ink composition for a writing instrument capable of suppressing ink leakage and improving writing performance, and a writing instrument using the same.

２．前記環状リン化合物の重量平均分子量が、３００００以下であることを特徴とする第１項に記載の筆記具用インキ組成物。
３．前記環状リン化合物の含有量が、インキ組成物全量に対して、５．０〜２５．０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インキ組成物。
４．前記筆記具用インキ組成物に、界面活性剤を含有することを特徴とする第１項〜第３項のいずれか１項に記載の筆記具用インキ組成物。
５．第１項〜第４項のいずれか１項に記載の筆記具用インキ組成物が収容されてなることを特徴とする筆記具。
６．インキ収容筒の先端部に、ボールを回転自在に抱持したボールペンチップを有し、前記インキ収容筒内に第１項ないし第４項のいずれか１項に記載の筆記具用インキ組成物を収容してなることを特徴とする油性ボールペン。」とする。 The present invention is to solve the above problems.
"1. An ink composition for a writing instrument containing a colorant, an organic solvent, and a cyclic phosphorus compound, wherein the cyclic phosphorus compound has the following general formula (Chemical formula 1).

2. The ink composition for writing instruments according to item 1, wherein the cyclic phosphorus compound has a weight average molecular weight of 30,000 or less.
3. 3. The ink composition for writing instruments according to item 1 or 2, wherein the content of the cyclic phosphorus compound is 5.0 to 25.0% by mass with respect to the total amount of the ink composition.
4. The writing instrument ink composition according to any one of items 1 to 3, wherein the writing instrument ink composition contains a surfactant.
5. A writing instrument comprising the ink composition for a writing instrument according to any one of paragraphs 1 to 4.
6. A ballpoint pen tip that rotatably holds a ball is provided at the tip of the ink accommodating cylinder, and the ink composition for writing instruments according to any one of items 1 to 4 is accommodated in the ink accommodating cylinder. An oil-based ballpoint pen that is characterized by being made of ink. ".

By containing the cyclic phosphorus compound of the following general formula (Chemical Formula 1), the present invention locally thickens the ink at the writing tip when the writing tip dries, and the ink fluidity of the writing tip Ink leakage (in the case of a ballpoint pen, ink leakage from the gap between the ball and the tip of the tip) is suppressed by lowering the surface drying time of the writing tip gap, and writing performance is improved by suppressing writing blurring. It was possible to obtain an ink composition for a writing instrument that can be used and a writing instrument using the same.

Hereinafter, embodiments of the present invention will be described in detail. In this specification, "part", "%", "ratio", etc. indicating the composition are based on mass unless otherwise specified, and the content is based on the mass of the water-based ink composition for writing instruments. Is the mass% of the constituents of.

A feature of the present invention is that the ink composition for writing instruments contains a cyclic phosphorus compound of the general formula (Chemical Formula 1).

(Cyclic phosphorus compound)
In the present invention, it has been found that the ink composition for writing instruments contains the cyclic phosphorus compound of the following general formula (Chemical Formula 1) to increase the viscosity of the ink and suppress ink leakage. .. This is because when the writing tip dries, the ink locally thickens at the writing tip, lowering the ink fluidity at the writing tip, and allowing the surface drying time of the writing tip gap to allow ink leakage (ballpoint pen). In this case, ink leakage from the gap between the ball and the tip of the chip) is suppressed. In particular, the cyclic phosphorus compound of the following general formula (Chemical Formula 1) is suitable when used as an oil-based ink composition because it has an effect of suppressing ink leakage.

The cyclic phosphorus compound used in the present invention is a compound having a cyclic structure containing a phosphorus element, but the polymer of the cyclic phosphorus compound increased the ink viscosity in the ink and further dried the writing tip. At the time, it is possible to suppress ink leakage from the writing tip by locally thickening the ink at the writing tip. Further, since the cyclic phosphorus compound has an affinity with a metal material at the tip of writing, the ink easily gets wet with the metal surface, and writing is suppressed by suppressing handwriting blurring regardless of the writing direction. It is possible to improve the sex. In particular, in the case of a ballpoint pen, ink is easily applied to the surface of a metal ball, and it is easy to suppress handwriting blurring, which is preferable.

Further, the cyclic phosphorus compound of the general formula (Chemical Formula 1) also has a rust preventive effect on the metal material and is preferable because it can be suitably used in the present invention. This is effective in preventing rust when a metal material such as stainless steel, brass, or nickel silver is used for the ballpoint pen tip body of the writing instrument member, the ink storage cylinder, or the like. Especially when a nickel silver material is used among the metal materials, it is effective.

The weight average molecular weight of the cyclic phosphorus compound is preferably 30,000 or less. This is because when the weight average molecular weight exceeds 30,000, it is difficult to dissolve and stabilize in the ink, so that the effect of the present invention is difficult to obtain. Considering the above effects, the weight average molecular weight is preferably 20000 or less.

The content of the cyclic phosphorus compound is preferably 5.0 to 25.0% 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 is difficult to suppress ink leakage, and if it exceeds 25.0% by mass, the dissolution stability is likely to be affected. Further, considering the above effect, 10.0 to 25.0% by mass is preferable, and more considering it, 15.0 to 20.0% by mass is preferable.

The ink viscosity of the ink composition for writing utensils of the present invention is not particularly limited, but when the cyclic phosphorus compound of the general formula (Chemical Formula 1) is used, ^{the ink at 20 ° C. and a shear rate of 5 sec -1} (at rest). If the viscosity exceeds 25,000 mPa · s, the writing performance, writing taste, and ink following performance tend to be inferior ^{. Therefore, the ink viscosity at 20 ° C. and a shear rate of 5 sec -1} (at rest) is preferably 25,000 mPa · s or less. Further, considering that the writing performance and the ink tracking performance are further improved, the ink viscosity is more preferably 8000 to 25000 mPa · s, and further, more preferably 1000 to 20000 mPa · s. Further, in a haunting type writing instrument such as a knock type writing instrument and a rotary feeding type writing instrument, it is necessary to further consider the suppression of ink leakage, and therefore 13000 to 20000 mPa · s 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.
Examples of 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, organic acids and basic dyes. Types such as salt-forming dyes with and salt-forming dyes with acidic dyes and organic amines can be mentioned. These dyes may be used alone or in combination of two or more. As the dye, it is preferable to use at least a salt-forming dye in consideration of the stability over time due to the compatibility with the cyclic phosphorus compound of the general formula (Chemical Formula 1), and further, the stability over time due to the stable salt-forming bond. It is preferable to use a salt-forming dye of a basic dye and an organic acid, a salt-forming dye of a basic dye of an acidic dye, and a salt-forming dye of an acidic dye and an organic amine in consideration of maintaining the above. Specifically, regarding the 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 (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. Specifically, 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 handwriting, and if it exceeds 30.0% by mass, it tends to affect the solubility in the ink. In consideration, it is preferably 7.0 to 25.0% by mass, and further considered, it is 10.0 to 25.0% by mass.

(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, propagil 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, considering the solubility with the cyclic phosphorus compound of the general formula (Chemical Formula 1), it is preferable to use a water-insoluble organic solvent to prepare an ink composition for writing instruments, and in particular, for writing instruments. It is preferable because it is easy to obtain the effect of suppressing ink leakage and improving the writing performance by stabilizing the dissolution of the oil-based ink composition.
Among them, it is preferable to use a glycol ether solvent. This is because when a glycol ether solvent is used, it easily absorbs moisture, so that the strength of the film formed when the tip of the chip dries is softened and the writing performance is easily improved. Considering the effectiveness and stability in the ink, it is preferable to use an aromatic glycol ether solvent. Further, as an organic solvent other than the glycol ether solvent, it is preferable to use an alcohol solvent, but this is because the alcohol solvent volatilizes and is easily dried at the tip of the chip, and the cyclic of the general formula (Chemical Formula 1). By containing a phosphorus compound, the inside of the writing tip (inside the tip) is thickened more quickly, thereby suppressing ink leakage from the gap between the writing tips (ink leakage from the gap between the ball and the tip). This is preferable because it improves the ink leakage suppression performance. Further, aromatic alcohols such as benzyl alcohol also have an effect of improving lubricity, and therefore it is preferable to use at least.

Regarding the organic solvent, when the content of the alcohol solvent with respect to the total amount of the ink composition is X and the content of the glycol ether solvent with respect to the total amount of the ink composition is Y, the relationship is 0.01 ≦ X / Y ≦ 3. Is preferable. This is preferably X / Y ≦ 3 because too much alcohol solvent tends to affect the writing performance, while too much glycol ether solvent absorbs too much water and the resin film becomes soft and the ink This is because 0.01 ≦ X / Y is preferable because it easily affects the hanging performance and the stability of the ink over time. Further, 0.1 ≦ X / Y ≦ 2 is preferable in consideration of further improving the writing performance.

The content of the organic solvent is preferably 10.0 to 90.0% by mass, and is dried at the tip of the chip, in consideration of improving solubility, handwriting drying property, bleeding, and the like. Considering the property, 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 modifier. As the resin, polyvinyl butyral resin, ketone resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, terpene resin, etc. Examples thereof include an alkyd resin, a phenoxy resin, and a polyvinyl acetate resin, and among them, a ketone resin is preferably contained. This is because the ink leakage suppressing effect can be more easily improved. Further, the ketone resin has an effect of suppressing ink leakage and also an effect of suppressing crying by using the cyclic phosphorus compound of the general formula (Chemical Formula 1) in combination with the ketone resin.

If the content of the resin is less than 1.0% by mass with respect to the total amount of the ink composition, the amount of resin film formed may be insufficient, and the ink leakage suppression performance tends to be inferior, and if it exceeds 40.0% by mass. Since the solubility in the ink 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 the ink leakage suppression performance, 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 taste and writing performance tend to be affected. 0 to 30.0% by mass is preferable.

As a resin other than the ink viscosity modifier such as a ketone resin, a spinnability imparting agent may be appropriately used. In particular, it is preferable to contain the polyvinylpyrrolidone resin because the binding property of the ink is enhanced and the generation of excess ink at the tip of the chip is easily suppressed by blending the polyvinylpyrrolidone resin. If the content of the polyvinylpyrrolidone resin is less than 0.01% by mass with respect to the total amount of the ink composition, it tends to be difficult to suppress the generation of excess ink. Therefore, if it exceeds 3.0% by mass, it is contained in the ink. Since the solubility tends to be inferior, 0.01 to 3.0% by mass is preferable with respect to the total amount of the ink composition. Considering the above reasons, 0.1 to 2.0% by mass is preferable. Specific examples thereof include trade names manufactured by ASP Japan Co., Ltd .; PVP K-15, PVP K-30, PVP K-90, PVP K-120 and the like. These may be used alone or in mixture of 2 or more types.

(Surfactant)
When a cyclic phosphorus compound or resin is used as in the present invention, it is preferable to use a surfactant in consideration of the writing performance of the film formed at the writing tip, and among them, a phosphoric acid ester is more considered. It is preferable to use a system surfactant or a fatty acid. This is because the use of phosphate ester surfactants or fatty acids tends to soften the film formed and may improve writing performance. Among them, the number of carbon atoms contained in the alkyl group of the phosphoric acid ester-based surfactant or fatty acid is preferably 10 to 20, and more preferably, the number of carbon atoms is 12 to 18. Further, considering the lubricity (high load performance) under a high writing pressure (300 to 500 gf), it is preferable to use a phosphate ester-based surfactant, which is a high writing pressure (300) in the case of a ballpoint pen. Even at ~ 500 gf), the lubricity between the ball and the chip body is improved, the wear of the ball seat is suppressed, and it is easy to obtain a good handwriting without blurring, so that it can be used more preferably in the present invention. is there.

Examples of the phosphoric acid ester-based surfactant include a phosphoric acid monoester of a polyoxyethylene alkyl ether or a polyoxyethylene alkylaryl ether, a phosphoric acid diester of a polyoxyethylene alkyl ether or a polyoxyethylene alkyl aryl ether, and a polyoxyethylene alkyl ether. Alternatively, a phosphoric acid triester of a polyoxyethylene alkylaryl ether, an alkyl phosphoric acid ester, an alkyl ether phosphoric acid ester or a derivative thereof and the like can be mentioned, and the alkyl group of the phosphoric acid ester-based surfactant is a styrene phenol-based or nonylphenol. Examples include systems, lauryl alcohol-based, tridecyl alcohol-based, and octylphenol-based. Examples of the fatty acid include oleic acid, stearic acid, linoleic acid and the like, and these phosphoric acid ester-based surfactants or fatty acids may be used alone or in combination of two or more. Among them, in consideration of lubricity (high load performance) under high writing pressure (300 to 500 gf), it is preferable to use a phosphoric acid ester-based surfactant, and in particular, the number of carbon atoms contained in the alkyl group is 5 to 5. It is preferably 18, and if further considered, the number of carbon atoms is more preferably 10 to 18, and more preferably, the number of carbon atoms is 12 to 18. It should be noted that if the number of carbon atoms of the alkyl group is excessively small, the lubricity tends to be insufficient, and if the number of carbon atoms is excessively large, the stability of the ink with time tends to be affected.

The content of the phosphoric acid ester-based surfactant is more preferably 0.1 to 5.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, 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 consideration is given, 0.5 to 3.0% by mass is most preferable.

Specific examples of the phosphoric acid ester-based surfactant include Plysurf A217E (alkyl group: 14 carbon atoms, acid value: 45 to 58) and A219B from the Plysurf series (Daiichi Kogyo Seiyaku Co., Ltd.). (Alkyl group: 12 carbon atoms, acid value: 44 to 58), A215C (alkyl group: 12 carbon atoms, acid value: 80 to 95), A208B (alkyl group: 12 carbon atoms, acid value: 135 to 155) ), A208N (alkyl group: mixture of 12 and 13 carbon atoms, acid value: 160 to 185), phospanol series (manufactured by Toho Kagaku Kogyo Co., Ltd.), phospanol RB-410 (alkyl group) : 18 carbon atoms, acid value: 80-90), RS-610 (alkyl group: 13 carbon atoms, acid value: 75-90), RS-710 (alkyl group: 13 carbon atoms, acid value: 55- 75) and the like. These surfactants may be used alone or in combination of two or more.

(Organic amine)
In the present invention, it is preferable to use an organic amine in consideration of the stability of the ink component in the ink. Amines having ethylene oxide such as oxyethylenealkylamine and polyoxyethylenealkylamine, alkylamines such as laurylamine and stearylamine, dimethylalkylamines such as distearylamine, dimethyllaurylamine, dimethylstearylamine and dimethyloctylamine, etc. Among them, amines having ethylene oxide and dimethylalkylamines are preferable in consideration of stability in ink. In particular, when a phosphoric acid ester-based surfactant is used, it is preferable because it is neutralized and stabilized in the ink, so that the effect of improving the writing performance and the writing taste can be easily obtained.

Regarding the reactivity of the organic amine with other components in the ink, the primary amine is the strongest, followed by the secondary amine and the tertiary amine, and the reactivity is smaller. It is preferable to use a secondary amine or a tertiary amine. These may be used alone or in mixture of 2 or more types.

Specific examples of organic amines include oxyethylene alkylamines, and specific examples of polyoxyethylene alkylamines include nymine L-201 (total amine value: 232-246, secondary amines) and L-202. (Total amine value: 192 to 212, tertiary 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 to 134, tertiary amine), S-210 (total amine value: 75 to 85, tertiary amine), DT-203 (total amine value: 227 to 247, 3, Grade amines), DT-208 (total amine value: 146 to 180, tertiary amines) (manufactured by Nippon Oil & Fats Co., Ltd.) and the like. Specific examples of the alkylamine include fermin 80 (total amine value: 204 to 210, primary amine), fermin D86 (total amine value: 110-119, secondary amine), and fermin DM2098 (total amine value: 254). ~ 265, tertiary amine), Farmin DM8680 (total amine value: 186 to 197, tertiary amine) (Kao Co., Ltd.), Nissan tertiary amine BB (total amine value: 243-263, tertiary amine), same FB (total amine value: 230 to 250, tertiary amine) (manufactured by Nippon Oil & Fats Co., Ltd.) and the like can be mentioned. These may be used alone or in mixture of 2 or more types.

The content of the organic amine is preferably 0.1 to 10.0% by mass with respect to the total amount of the ink composition in consideration of the stability with the salt-forming dye and other components, and the phosphoric acid described later. Considering neutralization with respect to the ester-based surfactant, 0.2 to 5.0% by mass is preferable.

Further, in the ink composition for writing utensils according to the present invention, as other additives, in order to improve the lubricity and the stability of the ink with time, (i) a surfactant, for example, a fluorine-based surfactant or a silicone-based surfactant. Agents, fatty acid alkanolamides, anionic surfactants, cationic surfactants, amphoteric surfactants, and salt-forming compounds of anionic surfactants and / or cationic surfactants, (ii). Pseudoplasticizing agents such as viscosity modifiers such as fatty acid amide, hydrogenated castor oil, and water as (iii) colorant stabilizers, (iv) plasticizers, (v) chelating agents, or (vi) auxiliary solvents. Etc. may be used as appropriate. These may be used alone or in combination of two or more.

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.

The material of the ball pen tip includes metal materials such as stainless steel, nickel silver, brass (brass), aluminum bronze and aluminum, and resin materials such as polycarbonate, polyacetal and ABS. A nickel silver chip body is preferable in consideration of properties, and a stainless steel chip body is preferable in consideration of wear of the ball seat and stability over time.

Example 1
The ink composition for writing utensils of Example 1 has a dye as a colorant, a benzyl alcohol as an organic solvent, an ethylene glycol monophenyl ether, a cyclic phosphorus compound, a ketone resin, a phosphoric acid ester-based surfactant as a surfactant, and an organic amine. Oxyethylene alkylamine and polyvinylpyrrolidone were used as a spinnability-imparting agent, weighed a predetermined amount, heated to 60 ° C., and then completely dissolved using a disper stirrer to obtain an ink composition for writing utensils. .. The specific blending amount is as follows.

Example 1 (ink blending)
Coloring agent (dye, salt-forming dye of acid dye and basic dye) 15.0% by mass
Colorant (dye, oil-soluble dye) 10.0% by mass
Organic solvent (benzyl alcohol) 32.4% by mass
Organic solvent (ethylene glycol monophenyl ether) 21.6% by mass
Cyclic phosphorus compound (Chemical formula 1) 10.0% by mass
Surfactant (phosphate ester-based surfactant) 2.0% by mass
Organic amine (oxyethylene alkylamine) 1.0% by mass
Ketone resin 7.5% by mass
Spinning property imparting agent (polyvinylpyrrolidone resin) 0.5% by mass

Examples 2-4
As shown in Table 1, ink compositions for writing instruments of Ink Dispensing Examples 2 to 4 were obtained in the same procedure as in Example 1 except that the ink components were changed. The measurement and evaluation results are shown in the table.

Comparative Examples 1 to 4
As shown in the table, the ink compositions for writing instruments of Comparative Examples 1 to 4 were obtained in the same procedure as in Example 1 except that the ink components were changed. The measurement and evaluation results are shown in the table.

Test and Evaluation The writing instrument ink composition (0.27 g) prepared in Examples 1 to 4 and Comparative Examples 1 to 4 is rotatably held in an ink storage cylinder (polypropylene) with a ball diameter of φ0.7 mm. A writing instrument was prepared by filling a refill for a writing instrument equipped with a ballpoint pen tip (made of metal). The following tests and evaluations were carried out using the writing paper JIS P3201 as the writing test paper.

Ink leakage suppression test: The pen tip was left facing downward for 7 days in an environment of 30 ° C. and 85% RH, and ink leakage from the tip tip was confirmed.
No ink droplets on the tip tip ・ ・ ・ ◎
Ink droplets on the tip of the chip are within 1/4 of the taper part ... ○
Ink droplets on the tip of the chip are 1/4 or more and 1/2 or less of the tapered part ... △
Ink droplets on the tip of the chip are more than 1/2 of the taper part ... ×

Writing performance test: After writing by hand, the state of handwriting was visually observed.
Cassoulet did not occur ... ◎
Cassoulet occurred, but it was at a level where there was no problem in practical use ... ○
It was a level where cassoulet occurred and there was a concern in practical use ... ×

Corrosion test: A metal (nickel silver) ballpoint pen tip was immersed in the ink composition for writing instruments of Examples and Comparative Examples at 80 ° C. for 3 days, and the corrosion state of the ballpoint pen tip was observed with a microscope.
Metallic luster with no discoloration or almost no discoloration ... ○
Those with no metallic luster and discoloration ... ×

In Examples 1 to 4, good performance was obtained in all of the ink leakage suppression test, the writing performance test, and the corrosion test.
Regarding the ink viscosity, when the ink viscosity was measured using a viscometer Viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield Co., Ltd., the shear rate was 5 sec ^-1 and the ink of Example 1 was measured in an environment of 20 ° C. The viscosity was 10000 mPa · s, and the ink viscosity of Example 2 was 15000 mPa · s.

In Comparative Examples 1 to 3, since the cyclic phosphorus compound was not used, the ink leakage suppression performance and the corrosion test were inferior.

In Comparative Example 4, the fatty acid amide wax was added as a shear thinning agent to increase the ink viscosity, but since the cyclic phosphorus compound was not used, the ink leakage suppression performance and the corrosion test were inferior.

Further, when a haunting type writing instrument (a hauling type ballpoint pen) such as a knock type writing instrument or a rotary feeding type writing instrument is used, the ink leakage suppression performance is one of the most important performances, and therefore, the writing tip portion as in the present invention. Ink composition for writing instruments containing a cyclic phosphorus compound as in the present invention, which can suppress ink leakage (ink leakage from the gap between the ball and the tip of the tip) from the gap of the ink leakage suppression performance. It is effective to use things.

In order to improve ink leakage suppression as in the present invention, in the case of a ballpoint pen, a ball rotatably held at the tip of the ballpoint pen tip is pressed against the inner wall of the tip edge of the tip directly by a coil spring or via a pressing body. Therefore, it is preferable to provide a valve mechanism that gives a gap between the inner wall of the tip edge of the chip and the ball to allow ink to flow out by the pressing force at the time of writing, and closes even a minute gap at the tip of the tip when not in use.

Further, in the present embodiment, for convenience, a writing tool in which a writing tool refill in which the writing tool ink composition is directly stored is illustrated is illustrated, but in the writing tool of the present invention, the shaft cylinder is contained in the ink housing cylinder. It may be a direct-packed ballpoint pen or a writing tool in which the ink composition for a writing tool is directly stored in the barrel. Further, in this embodiment, for convenience, a ballpoint pen tip formed by cutting a wire rod is illustrated, but a ballpoint pen tip formed by pressing a pipe material may be used.

Further, in the present embodiment, a writing tool in which a ballpoint pen refill containing an ink composition for a writing tool is arranged in a shaft cylinder is illustrated, but in the writing tool of the present invention, the shaft cylinder itself is used as an ink storage cylinder. , A direct-packed writing tool in which the ink composition for writing tools is directly stored in the shaft cylinder may be used, and a ballpoint pen containing the ink composition for writing tools in the ink storage cylinder (ballpoint pen refill) is used as it is. The structure may be the same.

The present invention can be used as a writing instrument, and more specifically, it can be widely used as a writing instrument such as a cap type or a haunting type or a ballpoint pen.

Claims (5)

Colorants, organic solvents, comprises a cyclic phosphorus compound, wherein the cyclic phosphorus compound represented by the following general formula (Formula 1) der is, weight average molecular weight, the ink composition for a writing instrument, characterized in that it is 30,000.

The ink composition for writing instruments according to claim 1, wherein the content of the cyclic phosphorus compound is 5.0 to 25.0% by mass with respect to the total amount of the ink composition. The ink composition for writing instruments according to claim 1 or 2 , wherein the ink composition for writing instruments contains a surfactant. A writing instrument comprising the ink composition for a writing instrument according to any one of claims 1 to 3. A ballpoint pen tip that rotatably holds a ball is provided at the tip of the ink accommodating cylinder, and the ink composition for writing instruments according to any one of claims 1 to 3 is accommodated in the ink accommodating cylinder. An oil-based ballpoint pen characterized by becoming.