JP2019131628A - Oily ink composition for writing instruments and writing instrument prepared therewith - Google Patents

Abstract

To provide an oily ink composition for writing instruments that suppresses ink leakage and gives an improved writing feel, and a writing instrument prepared therewith.SOLUTION: An oily ink composition for writing instruments contains a colorant, an organic solvent, and an organic titanium compound containing phosphorus or sulfur.SELECTED DRAWING: None

Description

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

  Conventional oil-based ink compositions for writing instruments, in the case of ballpoint pens, ink leaks from the gap between the writing tips (ink leaks from the gap between the ball and tip), and in the case of marking pens, sign pens, etc. In order to suppress ink leakage from the ink, a solvent having a vapor pressure at 25 ° C. of 0.001 mmHg or more is used, silica or terpene phenol resin is used as an ink leakage inhibitor, or a gelling agent is used as an ink. There has been proposed a technique for an ink composition for a writing instrument having a high viscosity.

  As such an oil-based ink composition for writing instruments, a technique using an alcohol, a polyhydric alcohol, or a glycol ether solvent having a vapor pressure at 25 ° C. of 0.001 mmHg or more is disclosed in Japanese Patent Application Laid-Open No. 2004-107591 “For writing instruments”. As a technique using an “oil-based ink composition” or an ink leakage inhibitor, JP-A-10-195365 “oil-based ink for ballpoint pen” using silica having a primary average particle diameter of 7 to 40 nm, an OH value of 150 or more As a technique using a certain terpene phenol resin, Japanese Patent Application Laid-Open No. 2007-126528 “oil-based ink for ballpoint pen”, and as a technique using a hydrogenated castor oil or a fatty acid amide wax as a shear thinning agent, Japanese Patent Application Laid-Open No. Hei 7 No. -196972, “Oil-based ink composition for ball-point pens”.

"Japanese Patent Laid-Open No. 2004-107591" "Japanese Patent Laid-Open No. 10-195365" "JP 2007-126528 A" "Japanese Patent Laid-Open No. 7-196972"

However, Patent Document 1 has an effect of suppressing ink leakage to some extent, but when the ink viscosity is lowered, ink leakage cannot be sufficiently suppressed only with 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 diameter and a large specific gravity of silica, so that the dispersion stability in oil-based ink is inferior. Since the terpene phenol resin having a viscosity of 150 or more has a high OH value, the solubility in oil-based ink is poor, and sufficient effects cannot be exhibited. In Patent Document 4, hydrogenated castor oil and fatty acid amide wax can suppress ink leakage to some extent, but the ink viscosity at rest increases, ink followability tends to be inferior, and the handwriting is blurred. Occasionally, it had a problem that affected writing quality.
In particular, in the case of a ballpoint pen, when the ball diameter is set to 1.0 to 2.0 mm, the ballpoint pen tip is set so as to increase the amount of ink discharged. The writing performance when dried is inferior.

  Furthermore, recently, in order to obtain a smooth writing feeling, oil-based inks have a low ink viscosity, and the amount of ink discharged is increased accordingly, and ink leakage is likely to occur from the gap between the writing tips, which is likely to cause problems. .

  An object of the present invention is to obtain an oil-based ink composition for a writing instrument that suppresses ink leakage and has a good writing quality, and a writing instrument using the same.

In order to solve the above problems, the present invention
“1. An oil-based ink composition for a writing instrument comprising a colorant, an organic solvent, a resin, and an organic titanium compound, wherein the organic titanium compound has phosphorus or sulfur.
2. 2. The oil-based ink composition for a writing instrument according to item 1, wherein the organic titanium compound is a titanium phosphate compound or a titanium sulfonate compound.
3. The oil-based ink composition for writing instruments according to item 1 or 2, wherein the content of the organic titanium compound is 0.1 to 10% by mass relative to the total amount of the ink composition.
4). The oil-based ink composition for a writing instrument according to any one of claims 1 to 3, wherein a blending ratio of the resin to the organic titanium compound is 0.1 to 10 times on a mass basis. object.
5). The oil-based ink composition for a writing instrument according to any one of Items 1 to 4, wherein the resin is a polyvinyl butyral resin.
6. The oil-based ink composition for a writing instrument according to any one of items 1 to 5, wherein the ink viscosity at 20 ° C. and a shear rate of 1.0 sec ⁻¹ is 100 to 10,000 mPa · s. .
7). A writing instrument comprising the oil-based ink composition for a writing instrument according to any one of items 1 to 6.
8). The tip of the ink storage cylinder has a ballpoint pen tip that rotatably holds a ball, and the oil-based ink composition for a writing instrument according to any one of items 1 to 7 is contained in the ink storage cylinder. An oil-based ballpoint pen characterized by being housed. "

  The present invention comprises an organotitanium compound having phosphorus (P) or sulfur (S) and a resin, thereby forming a cross-linked structure in the resin and imparting pseudoplasticity. A writing instrument with high writing quality that suppresses ink leakage from the gap between the writing tips (in the case of ballpoint pens, ink leakage from the gap between the ball and the tip of the tip), lowers the ink viscosity during writing An oil-based ink composition and a writing instrument using the same were obtained.

  In the present specification, “part”, “%”, “ratio” and the like indicating the composition are based on mass unless otherwise specified.

  A feature of the present invention is that the oil-based ink composition for writing instruments comprises an organic titanium compound having phosphorus (P) or sulfur (S).

  By including an organic titanium compound having phosphorus (P) or sulfur (S) in the oil-based ink composition for writing instruments, the organic titanium compound forms a three-dimensional cross-linked structure by cross-linking resins. In addition, it was found that ink leakage can be suppressed from the gap at the tip of the writing by imparting pseudoplasticity, and the writing quality can be kept good. This is because the organic titanium compound acts as a cross-linking agent to cross-link resins to form a three-dimensional cross-linked structure and to exhibit ink viscosity.

(Organic titanium compound)
About the organic titanium compound used by this invention, the titanium compound which has phosphorus (P) or sulfur (S) in a structure is used, and the effect as a crosslinking agent is acquired. Therefore, by using together a titanium compound having phosphorus (P) or sulfur (S) in the structure and a resin, in the ink, the organic titanium compound crosslinks the resins to form a three-dimensional crosslinked structure. It is presumed that a stable cross-linked structure can be easily obtained by having titanium. As a result, the ink viscosity at rest can be set high, and by suppressing the flow of ink, ink oozes out from the gap at the tip of the writing (in the case of a ballpoint pen, ink leaks from the gap between the ball and the tip of the tip). This is because it is easy to suppress ink leakage from the gap at the writing tip (ink leakage from the gap between the ball and tip). Furthermore, the ink viscosity is lowered and the writing quality can be kept good because the crosslinked structure can be temporarily broken by an impact such as shearing at the time of writing. In particular, by using phosphorus or sulfur having an extreme pressure effect, when used in a ballpoint pen, it is presumed that the lubricity between the ball and the ball seat can be improved more easily and the effect of improving the writing quality can be obtained. .
Therefore, by using together with the said organic titanium compound and resin, it can be used suitably for the oil-based ink composition for writing instruments, and can be used suitably especially in an oil-based ball-point pen.

  The organic titanium compound having phosphorus or sulfur used in the present invention is preferably a titanium phosphate compound or a titanium sulfonate compound in view of stably exhibiting an effect as a crosslinking agent in the ink. Furthermore, it is preferable to use an organotitanium compound having phosphorus, considering that the effects of the present invention are easily exhibited by facilitating the formation of a more stable cross-linked structure. Is preferably used.

In addition, the titanium phosphate compound preferably has a phosphate ester as a functional group or a ligand in the structure in consideration of suppressing ink leakage and further improving writing quality.
The titanium sulfonate compound preferably has an alkylallyl sulfonic acid as a functional group or a ligand in the structure, considering that the ink leakage is suppressed and the writing quality is further improved. It is preferable to have alkylbenzene sulfonic acid.

  The content of the organic titanium compound having phosphorus or sulfur is preferably 0.1 to 10% by mass with respect to the total amount of the ink composition. If the amount is less than 0.1% by mass, it is difficult to obtain an effect as a cross-linking agent, the ink viscosity at rest is difficult to increase, and it is difficult to suppress ink leakage. If the amount exceeds 10% by mass, the ink viscosity is high. This is because the writing quality and ink followability tend to be poor. Furthermore, if the above effect is considered, 0.5 to 7% by mass is preferable, and if more considered, 1 to 5% by mass is preferable.

The ink viscosity of the oil-based ink composition for writing instruments of the present invention is not particularly limited. However, when an organic titanium compound having phosphorus or sulfur is used, the ink leakage suppressing effect is remarkably achieved by the formed crosslinked structure. Since it is easy to obtain, it is effective even at an ink viscosity of 100 to 10000 mPa · s at 20 ° C. and a shear rate of 1.0 sec ⁻¹ (at rest). If considered, the ink viscosity is preferably 500 to 5000 mPa · s, and if considered further, the ink viscosity is preferably 1000 to 3000 mPa · s.
In addition, in the writing type writing tools such as the knock type writing tool and the rotary feeding type writing tool, it is effective because it is necessary to consider the ink leakage suppression more.
In addition, in the writing type writing tools such as the knock type writing tool and the rotary feeding type writing tool, it is effective because it is necessary to consider the ink leakage suppression more.

When an organotitanium compound having phosphorus or sulfur is used, the non-Newtonian viscosity index is “n” in the viscosity equation represented by S = αDn (where 1>n> 0). Point to. S represents the shear stress (dyne / cm ² ), D represents the shear rate (s ⁻¹ ), and α represents the non-Newtonian viscosity coefficient. When the non-Newtonian viscosity imparting index n is less than 0.55, writing performance such as writing quality and ink followability tends to be poor, and when n exceeds 0.90, ink leakage is likely to occur. Therefore, the non-Newtonian viscosity imparting index n is preferably 0.4 to 0.95. Considering the above effect, 0.55 to 0.8 is preferable, and 0.5 to 0.7 is more preferable.

(resin)
In addition, it is necessary to use a resin in order to further improve ink leakage suppression by forming a crosslinked structure and imparting pseudoplasticity by crosslinking the organic titanium compound used in the present invention with the resin. Examples of the resin include polyvinyl butyral resin, ketone resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, terpene resin, alkyd resin, phenoxy resin, polyvinyl acetate resin, and polyvinylpyrrolidone resin. Among them, polyvinyl butyral It preferably comprises a resin. This is because the organic titanium compound used in the present invention easily forms a crosslinked structure with the polyvinyl butyral resin, suppresses ink leakage, and improves the writing quality. Particularly, an oil-based ballpoint pen having a structure having a ballpoint pen tip that rotatably holds the ball is more effective and preferable.
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.

Moreover, it is preferable that polyvinyl butyral resin shall be 20-50 mol% of hydroxyl groups amount. This is because the organic titanium compound is easily crosslinked with respect to the hydroxyl group of the polyvinyl butyral resin within the above range, and the effect of the present invention is easily exhibited by forming a crosslinked structure. Furthermore, it is preferable to use a polyvinyl butyral resin having a hydroxyl amount of 30 to 45 mol, considering that it is easy to form a stable crosslinked structure in the ink and that the writing quality is easily improved. A hydroxyl group content of 30 to 40 mol% is preferred.
The hydroxyl content (mol%) of the polyvinyl butyral resin is the content of hydroxyl groups (mol%) with respect to the total molar amount of butyral groups (mol%), acetyl groups (mol%), and hydroxyl groups (mol%). Indicates the rate.

The average degree of polymerization of the polyvinyl butyral resin is preferably 150 or less. This is because when the average degree of polymerization exceeds 1500, the organic titanium compound and the crosslinked structure become too dense, the ink fluidity tends to be poor, the ink viscosity tends to be high, and the writing performance and writing quality are affected. This is because there is a tendency, and considering the more, the average degree of polymerization is preferably 1000. Furthermore, considering more, the average degree of polymerization is preferably 1000 or less. Furthermore, if the ink leakage suppression effect is considered, the average degree of polymerization is preferably 100 to 700.
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 defined in JISK6728 (2001 version) can be adopted.

Moreover, it is preferable that polyvinyl butyral resin shall be 50 to 80 mol% of butyral degree, considering that ink leakage suppression and writing quality are improved by the crosslinking effect with the organic titanium compound. Furthermore, considering that it is easy to form a stable crosslinked structure in the ink, the degree of butyralization is preferably 60 to 80 mol%.
The hydroxyl content (mol%) of the polyvinyl butyral resin is the content of hydroxyl groups (mol%) with respect to the total molar amount of butyral groups (mol%), acetyl groups (mol%), and hydroxyl groups (mol%). Indicates the rate.
In particular, in the case of a ballpoint pen, when the ball diameter is made larger than usual and is 1.0 mm to 2.0 mm, the influence of ink leakage is likely to occur from the gap between the ballpoint pen tip body and the ball, so polyvinyl butyral resin is used. It is effective when used, and it is more effective when the organic titanium compound having phosphorus or sulfur used in the present invention and polyvinyl butyral resin are used in combination, and more effective particularly when the thickness is set to 1.2 mm to 2.0 mm. .

  As for the polyvinyl butyral resin, specifically, trade names manufactured by Sekisui Chemical Co., Ltd .; ESREC BL-1 (butyralization degree: 60 to 66 mol, hydroxyl group amount: 36 mol%, average polymerization degree: 300), BL -1H (degree of butyralization: 66-72 mol, hydroxyl group amount: 30 mol%), BL-2 (degree of butyralization: 60-66 mol, hydroxyl group amount: 36 mol%, average polymerization degree: 450), BL-2H (butyral) Degree of conversion: 67-73 mol, hydroxyl group amount: 29 mol%), BL-5 (butyralization degree: 77 mol or more, hydroxyl group amount: 21 mol%), BL-10 (butyralization degree: 68-74 mol, hydroxyl group amount: 28 mol) %), The same BL-S (degree of butyralization: 71 to 77 mol, the amount of hydroxyl group: 22 mol%, the average degree of polymerization: 350), the same BM-1 ( Degree of tyralization: 62 to 68 mol, Amount of hydroxyl group: 34 mol%, Average degree of polymerization: 650), BM-2 (Degree of butyralization: 65 to 71 mol, Amount of hydroxyl group: 31 mol%, Average degree of polymerization: 800), BM- 5 (butyralization degree: 62 to 68 mol, hydroxyl group amount: 34 mol%, average polymerization degree: 850), BH-3 (butyralization degree: 62 to 68 mol, hydroxyl group amount: 34 mol%, average polymerization degree: 1700), BH -6 (butyralization degree: 66-72 mol, hydroxyl group amount: 30 mol%, average polymerization degree: 1300), BX-1 (hydroxyl group amount: 33 ± 3 mol%, average polymerization degree: 1700), BX-5 (hydroxyl group) Amount: 33 ± 3 mol%, average polymerization degree: 2400), BM-1 (butyralization degree: 62-68 mol, hydroxyl group amount: 34 mol%, average polymerization degree: 650) Same BM-2 (degree of butyralization: 65-71 mol, hydroxyl group amount: 31 mol%, average degree of polymerization: 800), same BM-5 (degree of butyralization: 62-68 mol, amount of hydroxyl group: 34 mol%, average degree of polymerization: 850) ), BM-S (degree of butyralization: 70 to 76 mol, amount of hydroxyl group: 22 mol%), etc., trade name of Kuraray Co., Ltd .; Mobital B20H (degree of butyralization: 67 to 74 mol, amount of hydroxyl group: 26 to 31 mol) %, Average polymerization degree: 250-500), B30T (butyralization degree: 59-66 mol, hydroxyl group amount: 33-38 mol%, average polymerization degree: 400-650), B30H (butyralization degree: 66-74 mol), Hydroxyl group amount: 26 to 31 mol%), B45H (degree of butyralization: 66 to 74 mol, hydroxyl group amount: 26 to 31 mol%, average) Concentration: 600 to 850), B60T (degree of butyralization: 59 to 66 mol, hydroxyl content: 33 to 38 mol%, average polymerization degree: 750 to 1000), B60H (degree of butyralization: 66 to 74 mol, hydroxyl content: 26) -31 mol%, average polymerization degree: 750-1000), the same B75H (butyralization degree: 66-74 mol, hydroxyl group amount: 26-31 mol%, average polymerization degree: 1500-1750). You may use these individually or in mixture of 2 or more types.

  If the total content of the resin is less than 0.1% by mass with respect to the total amount of the ink composition, the crosslinked structure is not sufficient, so that it is difficult to suppress ink leakage. Since solubility is easy to be inferior, 0.1-20 mass% is preferable with respect to the ink composition whole quantity. Furthermore, if considering ink leakage suppression and the like, 0.5 to 10% by mass is preferable, and if more considered, 0.5 to 5.0% by mass is preferable.

    In addition, the blending ratio of the resin to the organic titanium compound (resin / organic titanium compound) is preferably 0.1 to 10 times, and preferably 0.1 to 5 times on a mass basis. Preferably, it is 0.5 to 3 times. This is because the resin is likely to form a crosslinked structure within the above range, and ink leakage suppression and writing effect can be easily obtained.

(Coloring agent)
The colorant used in the present invention is not particularly limited, such as dyes and pigments, and can be appropriately selected and used. Dyes and pigments may be used in combination.
As dyes, oil-soluble dyes, acid dyes, basic dyes, metal-containing dyes, and various salt-forming dyes thereof, salt dyes of acid dyes and basic dyes, organic acids and basic dyes And the like, and salt-forming dyes of acid dyes and organic amines. 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 stability over time due to compatibility with an organotitanium compound having phosphorus or sulfur, and the stability over time can be maintained because the salt-forming bond is stable. In view of this, 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 with an acid dye, or a salt-forming dye of an acid dye and an organic amine. For example, a salt-forming dye of a basic dye and an organic acid is preferable. Furthermore, as for organic acids constituting salt-forming dyes, organic acids having a phenylsulfone group can easily form a lubricating film that easily adsorbs to metals, improve lubricity, and suppress wear on writing taste and ball seats. In particular, alkylbenzene sulfonic acid, naphthalene sulfonic acid, naphthalene sulfonic acid-formaldehyde condensate, alkyl diphenyl ether disulfonic acid, and polyoxyethylene alkyl phenyl ether phosphoric acid can be mentioned. In view of this, it is preferable to use alkylbenzenesulfonic acid as the organic acid.
Regarding the dye, specifically, 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, Nigrosine Base EXBP, Nigrosine Base EX, BASE OF BASIC DYES ROB-B, BASE OF BASIC DYES RO6 -B, BASE OF BASIC DYES VPB-B, BASE OF BASIC DYES VB-B, BASE OF BASIC DYES MVB-3 (above, 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.M. P. T.A. Blue 111, S.I. P. T.A. Blue GLSH-Special, S. P. T.A. Red 533, S.D. P. T.A. Orange 6, S. B. N. Violet 510, S.I. B. N. Yellow 530, S.I. R. C-BH (above, manufactured by Hodogaya Chemical Co., Ltd.) and the like.

  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 include pyrrolopyrrole, quinophthalone, selenium, triphenylmethane, perinone, perylene, dioxazine, metallic pigments, pearl pigments, fluorescent pigments, and phosphorescent pigments.

As the colorant, it is preferable to use a pigment. This is because pigment particles are used, and in the case of a ballpoint pen, a physical obstacle is caused in the gap between the ball and the inner wall of the tip of the chip, thereby suppressing ink leakage. It is because it is easy to do. Furthermore, since the pigment dispersion effect is acquired simultaneously, it is preferable. A pigment is preferable because it has excellent handwriting fastness and particularly excellent light resistance.
Furthermore, by using a pigment, in the case of a ballpoint pen, pigment particles enter the gap between the ball and the chip body, so that the action like a bearing is likely to work, and by suppressing metal contact, the lubricity is improved. It is preferable to use a pigment because the effect of improving writing quality and suppressing wear of the ball seat is easily obtained. Since the writing quality can be improved by reducing the viscosity of ink at the time of writing using an organic titanium compound having phosphorus or sulfur as in the present invention, it is preferable to use a pigment.

  In consideration of lubricity, it is preferable to use the pigment from among carbon black, quinacridone, selenium, and diketopyrrolopyrrole pigments.

  The content of the colorant is preferably 5 to 30% by mass with respect to the total amount of the ink composition. If it is less than 5% by mass, it tends to be difficult to obtain a dark handwriting, and if it exceeds 30% by mass, it tends to affect the solubility in ink. It is preferably 7 to 25% by mass, and further considering it is 10 to 25% 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, 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, ethanol , 1-propanol, 2- As oil-based inks such as alcohol solvents such as lopanol, isopropanol, isobutanol, t-butanol, propargyl alcohol, allyl alcohol, 3-methyl-1-butyn-3-ol, ethylene glycol monomethyl ether acetate and other higher alcohols The organic solvent generally used can be illustrated.

  Among these organic solvents, in view of solubility with an organic titanium compound having phosphorus or sulfur, it is preferable to use a water-insoluble organic solvent as an oil-based ink composition for writing instruments, and among them, glycol ethers It is preferable to use a solvent. This is because, when a glycol ether solvent is used, the effect is easily exhibited by stabilizing the dissolution in the ink. Furthermore, it is preferable to use an alcohol solvent for the organic solvent other than the glycol ether solvent, but this is because the alcohol solvent is volatilized and is easily dried at the tip of the chip, and has an organic titanium compound having phosphorus or sulfur. Is contained in the writing tip portion (inside the tip tip portion) to increase the viscosity locally, thereby suppressing ink leakage from the gap at the writing tip portion and improving the ink leakage suppressing performance. Furthermore, aromatic alcohol such as benzyl alcohol is preferably used at least because it has an effect of improving lubricity.

  Further, the content of the organic solvent is preferably 10 to 90% by mass with respect to the total amount of the ink composition in consideration of improving solubility, handwriting drying property, bleeding, etc., and considering the drying property at the tip of the chip. 20 to 90% by mass is preferable, and 40 to 70% by mass is more preferable.

(Surfactant)
In the present invention, it is easy to improve the writing quality by improving the lubricity, and it is considered to improve the writing performance when the tip end portion is dried in the state where the tip end portion is left in the atmosphere. For example, it is preferable to use a surfactant. This is because the lubricity layer formed of the surfactant can easily improve the lubricity, further soften the film formed of the surfactant, and improve the writing performance. Examples of the surfactant include fatty acids, silicone surfactants, fluorine surfactants, phosphate ester surfactants, and the like. Among these, in consideration of the above effects, it is preferable to use one or more of fatty acids, silicone surfactants, and phosphate ester surfactants.
In particular, when used with ballpoint pens, phosphate ester surfactants have phosphate groups, so that they are easily adsorbed to ballpoint pen tips and balls such as metals, and a lubricating effect is easily obtained. It is preferable to use an activator, and an extreme pressure effect is obtained between the ball, which is a metal material, and the ball seat by using in combination with the organic titanium compound having phosphorus (P) or sulfur (S) used in the present invention. This is preferable because it is easy to improve the lubricity. Further, when using the polyvinyl butyral resin described above, the ink layer formed from polyvinyl butyral and the lubricating layer are more preferable because the lubricity is improved and the writing quality is easily improved. It is preferable to use an agent and a polyvinyl butyral resin in combination.

The surfactant preferably has an HLB value of 10 to 20 because it is difficult to inhibit the formation of a crosslinked structure of the organic titanium compound in consideration of compatibility with the organic titanium compound. In consideration of forming a crosslinked structure of the organic titanium compound and improving lubricity and writing performance, the HLB value is preferably 10 to 17. Furthermore, if the HLB value exceeds 15, the hydrophilicity tends to be strong, so the solubility in oil-based ink tends to be poor, so the effect of the surfactant is difficult to obtain, and the lubricating effect is difficult to obtain. Is preferably 10-15.
In addition, HLB can be calculated | required from the Griffin method, the Kawakami method, etc. In particular, in the pendant type writing tools such as knock type writing tools and rotary feeding type writing tools, the pen tip is always exposed to the outside, unlike the cap type writing tools, which affects the writing performance when the writing tip is dry. Since it is easy, it is more preferable to use the surfactant having the above HLB value.

Specific examples of the surfactant include fatty acids such as oleic acid, stearic acid, and linoleic acid. Examples of the silicone surfactant include dimethyl silicone, methylphenyl silicone, polyether-modified silicone, and higher grades. Fatty acid ester-modified silicone and the like. Examples of fluorosurfactants include perfluoro group butyl sulfonate, perfluoro group-containing carboxylate, perfluoro group-containing phosphate ester, and perfluoro group-containing phosphate ester type. Products, perfluoroalkyl betaines, perfluoroalkylamine oxide compounds, and the like. Phosphate ester surfactants include polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphate monoester, polyoxyethylene. Examples include phosphoric acid diesters of lenalkyl ethers or polyoxyethylene alkyl aryl ethers, phosphoric acid triesters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers, alkyl phosphoric acid esters, alkyl ether phosphoric acid esters or derivatives thereof. . In addition, when using a phosphate ester-based surfactant, the acid value is preferably 150 or less. This is to facilitate the improvement of lubricity due to the phosphate ester-based surfactant. In consideration of stability in ink and lubricity, the acid value is preferably 30 to 130, and more preferably, the acid value is preferably 50 to 120. The acid value is contained in 1 g of the sample. It shall represent with the number of mg of potassium hydroxide required to neutralize an acidic component.

  As for content of surfactant, 0.1-5.0 mass% is more preferable with respect to the ink composition whole quantity. 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 aging tends to become unstable, and this tendency Is considered to be 0.3 to 3.0% by mass relative to the total amount of the ink composition, and 0.5 to 3.0% by mass is most preferable considering 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. Amine having ethylene oxide such as oxyethylene alkylamine and polyoxyethylene alkylamine, alkylamine such as laurylamine and stearylamine, dimethylalkylamine such as distearylamine, dimethyllaurylamine, dimethylstearylamine and dimethyloctylamine Among these, amines having ethylene oxide and dimethylalkylamine are preferable in consideration of stability in ink, and dimethylalkylamine is preferable in consideration of further stability. In particular, when a phosphate ester surfactant is used, it is preferable to neutralize and stabilize in ink, so that an effect of improving writing quality and writing performance can be easily obtained.

  In addition, regarding the reactivity between the organic amine and other components in the ink, the primary amine is the strongest, and then the reactivity with the secondary amine and the tertiary amine is small. It is preferable to use a secondary amine or a tertiary amine. You may use these individually or in mixture of 2 or more types.

Furthermore, the total amine value of the organic amine is preferably 100 to 300 (mgKOH / g) in consideration of the stability with dyes and other ink components. If this exceeds 300 (mgKOH / g), the reactivity is strong, so that it easily reacts with the dye and other ink components, so that the ink aging stability tends to be poor. Further, if the total amine value is less than 100 (mgKOH / g), the stability of the components in the ink is likely to be affected, and further, neutralization of the phosphate ester surfactant becomes insufficient. The stability with time of ink tends to be affected, and when an oil-based ballpoint pen is used, the adsorptivity of metals such as balls and chip bodies tends to be poor, and lubrication performance is difficult to obtain. Considering the stability and lubricity with dyes and phosphate ester surfactants more, the range of 150 to 300 (mgKOH / g) is preferable, and considering more, 200 to 300 (mgKOH / g). Is preferred.
The total amine value represents the total amount of primary, secondary, and tertiary amines, and is expressed in mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize 1 g of the sample.

  As for the organic amine, specifically, as oxyethylene alkylamine and polyoxyethylene alkylamine, specifically, Nimine L-201 (total amine number: 232 to 246, secondary amine), 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 amine), DT-208 (total amine number: 146 to 180, tertiary amine) (manufactured by NOF Corporation) and the like. Specific examples of the alkylamine include Farmin 80 (total amine number: 204-210, primary amine), Farmin D86 (total amine number: 110-119, secondary amine), Farmin DM2098 (total amine number: 254). -265, tertiary amine), Farmin DM 8680 (total amine number: 186-197, tertiary amine) (Kao Corporation), Nissan tertiary amine BB (total amine number: 243-263, tertiary amine), the same Examples include FB (total amine value: 230 to 250, tertiary amine) (manufactured by NOF Corporation). You may use these individually or in mixture of 2 or more types.

  The content of the organic amine is preferably 0.1 to 10% 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 phosphate ester-based surface activity. Considering neutralization with respect to the agent, 0.1 to 5% by mass is preferable.

  In addition, the ink composition for writing instruments according to the present invention includes (i) surfactants such as fatty acid alkanolamides and anionic surfactants as other additives in order to improve lubricity and ink aging stability. (Ii) viscosity modifiers such as fatty acid amides, hydrogenated castor oils, cationic surfactants, amphoteric surfactants, anionic surfactants and / or salt forms of cationic surfactants In addition, (iii) a colorant stabilizer, (iv) a plasticizer, (v) a chelating agent, or (vi) water as a co-solvent may be appropriately used. These may be used alone or in combination of two or more.

  In the case of a ballpoint pen, it is preferable that the amount of movement of the ballpoint chip tip in the vertical axis direction is 3 to 25 μm. This is because if it is less than 3 μm, it becomes difficult to obtain a dark handwriting or good writing taste, and if it exceeds 25 μm, ink leakage suppression, crying, and ink following performance are likely to be affected. 3 to 20 μm is preferable, and in consideration of the above, it is preferable to set the movement amount in the vertical axis direction to 5 to 16 μm.

  The arithmetic average roughness (Ra) of the ball surface of the ball-point pen tip is preferably 0.1 to 12 nm. This is because when the arithmetic average roughness (Ra) is less than 0.1 nm, it is difficult to place ink sufficiently on the surface of the ball, and it is difficult to obtain a dark handwriting at the time of writing. If the roughness (Ra) exceeds 12 nm, the ball surface is too rough and the ball and ball seat have high rotational resistance, so the writing quality tends to be inferior, and the writing performance such as blurring, line skipping, and line unevenness in the handwriting. It is because it becomes easy to have an influence on. The arithmetic average roughness (Ra) of 0.1 to 10 nm is more preferable when the polyvinyl butyral resin is used because the ink is easily placed on the ball surface. Is preferred. In addition, the measurement of surface roughness can be calculated | required by (model name SPI3800N by Seiko Epson Corporation).

The material used for the ball is not particularly limited, but a cemented carbide ball mainly composed of tungsten carbide, a metal ball such as stainless steel, a ceramic such as silicon carbide, silicon nitride, alumina, silica, zirconia, etc. Ball, ruby ball and the like.
The ball diameter is not particularly limited, but if the ball diameter is large, ink leaks easily from the gap between the ballpoint pen tip body and the ball, and the writing performance tends to be poor when the writing tip is dried. In the case of 1.0 mm to 2.0 mm larger than usual, it is easy to influence, and it is effective to use the organic titanium compound having phosphorus or sulfur used in the present invention, particularly 1.2 mm to 2 mm. When it is set to 0.0 mm, it is remarkable and more effective.

  Ballpoint pen tip materials include metal materials such as stainless steel, white, brass (brass), aluminum bronze, and aluminum, and resin materials such as polycarbonate, polyacetal, and ABS. Considering the property and cost, it is preferable to use a stainless steel chip body.

Example 1
The oil-based ink composition for a writing instrument of Example 1 is obtained by dissolving a polyvinyl butyral resin in an organic solvent at 60 ° C. using a disper stirrer, and then coloring agent, phosphate ester surfactant, organic amine, polyvinylpyrrolidone. The resin was sampled and stirred to completely dissolve, then the titanium phosphate compound was sampled and stirred, and then cooled to room temperature to obtain an oil-based ink composition for writing instruments.
Specific blending amounts are as follows. Ink viscosity in Example 1 was measured using a viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield Co., Ltd. Under a 20 ° C. environment, a shear rate of 1.0 sec ⁻¹ and an ink viscosity of 1100 mPa In the environment of s and 20 ° C., the ink viscosity was 280 mPa · s at a shear rate of 40 sec ⁻¹ . The non-Newtonian viscosity imparting index n was 0.65.

Example 1 (Ink formulation)
Colorant (dye, salt-forming dye of basic dye and organic acid) 10.0% by mass
Colorant (dye, salt-forming dye of acid dye and amine) 5.0% by mass
Organic solvent (benzyl alcohol) 47.0% by mass
Organic solvent (ethylene glycol monophenyl ether) 30.0% by mass
Titanium phosphate compound 1.5% by mass
Surfactant (phosphate ester surfactant) 2.0% by mass
Organic amine (oxyethylene alkylamine) 2.0% by mass
Polyvinylpyrrolidone resin 0.5% by mass

Examples 2-10
As shown in Table 1, oil-based ink compositions for writing instruments of Ink Examples 2 to 10 were obtained in the same procedure as Example 1 except that the ink components were changed. The measurement and evaluation results are shown in the table.

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

Test and Evaluation The oil-based ink composition for writing instruments (0.27 g) produced in Examples 1 to 10 and Comparative Examples 1 to 4 is freely rotatable with an ink container (polypropylene) having a ball diameter of φ0.7 mm. A pen for a ballpoint pen (having a coil spring in which the ball is directly pressed against the inner wall of the tip end edge of the chip, the movement amount of the ball in the axial direction: 8 μm, the arithmetic average roughness (Ra) of the ball surface: 5 nm) An oil-based ballpoint pen refill was filled to prepare an oil-based ballpoint pen. The following tests and evaluations were performed using a writing paper JIS P3201 as a writing test paper.

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

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

In Examples 1 to 10, good performance was obtained for both the ink leakage suppression test and writing quality.
Ink viscosity of Examples 2, 3, and 9 was measured using a viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield Co., and a non-Newtonian viscosity imparting index n was calculated.
In Example 2, in an environment of 20 ° C., shear rate of 1.0 sec ⁻¹ , ink viscosity = 1900 mPa · s, in an environment of 20 ° C., shear rate of 40 sec ⁻¹ , ink viscosity = 400 mPa · s, non-Newtonian viscosity index n was 0.58.
In Example 3, in an environment of 20 ° C., a shear rate of 1.0 sec ⁻¹ , ink viscosity = 2060 mPa · s, in an environment of 20 ° C., a shear rate of 40 sec ⁻¹ , ink viscosity = 410 mPa · s, non-Newtonian viscosity imparting index n was 0.56.
In Example 9, in an environment of 20 ° C., shear rate of 1.0 sec ⁻¹ , ink viscosity = 3370 mPa · s, in an environment of 20 ° C., shear rate of 40 sec ⁻¹ , ink viscosity = 590 mPa · s, non-Newtonian viscosity imparting index n was 0.53.

  In Comparative Examples 1 to 3, since the organic titanium compound containing phosphorus or sulfur was not used, the ink leakage suppression performance was inferior.

  In Comparative Example 4, fatty acid amide wax was added as a shear thinning agent to increase the ink viscosity, but a sufficient ink leakage inhibiting effect and writing quality were not obtained.

  In addition, when using an in / out type writing tool (in / out type ballpoint pen) such as a knock-type writing tool or a rotary pay-out type writing tool, the ink leakage suppression performance is one of the most important performances. Oil leakage for writing instruments containing the organotitanium compound as in the present invention, which can suppress ink leakage from the gap of the ink (ink leakage from the gap between the ball and the tip of the chip) and improve ink leakage suppression performance. It is effective to use an ink composition.

  As in the present invention, in order to suppress ink leakage and improve writing performance, the ball held rotatably at the tip of the ballpoint pen tip is pressed against the inner wall of the tip tip edge directly by a coil spring or via a pressing body. In addition, it is preferable to provide a valve mechanism that causes the ink to flow out by providing a gap between the inner wall of the tip end edge and the ball by pressing force at the time of writing, and closing the minute gap at the tip end when not in use.

Further, in this embodiment, for the sake of convenience, an oil-based ballpoint pen containing an oil-based ballpoint pen refill in which a writing instrument ink composition is directly accommodated in the shaft cylinder is illustrated, but the writing instrument of the present invention uses the shaft cylinder as an ink. It may be a writing instrument such as a direct-filled ballpoint pen, a marking pen, or a signing pen, which is an accommodating cylinder and directly accommodates an ink composition for a writing instrument in a shaft cylinder. Moreover, when it is set as the marking pen and the sign pen which accommodated the ink composition for writing instruments directly in the axial cylinder, since the effect which suppresses an ink leak, an ink splatter drop, etc. is acquired, it can use suitably.
Further, in this embodiment, for the sake of convenience, a ballpoint pen tip formed by cutting a wire rod is illustrated, but a ballpoint pen tip formed by pressing a pipe member may be used.

The present invention can be used as a writing instrument. More specifically, the present invention can be widely used as a ball pen, a marking pen, and a sign pen as a writing instrument such as a cap type and a retractable type.

Claims (8)

An oil-based ink composition for a writing instrument comprising a colorant, an organic solvent, a resin, and an organic titanium compound, wherein the organic titanium compound has phosphorus or sulfur. The oil-based ink composition for a writing instrument according to claim 1, wherein the organic titanium compound is a titanium phosphate compound or a titanium sulfonate compound. The oil-based ink composition for a writing instrument according to claim 1 or 2, wherein the content of the organic titanium compound is 0.1 to 10% by mass with respect to the total amount of the ink composition. 4. The oil-based ink composition for a writing instrument according to claim 1, wherein a blending ratio of the resin to the organic titanium compound is 0.1 to 10 times on a mass basis. The oil-based ink composition for a writing instrument according to any one of claims 1 to 4, wherein the resin is a polyvinyl butyral resin. 6. The oil-based ink composition for a writing instrument according to claim ^1, wherein the ink viscosity at 20 ° C. and a shear rate of 1.0 sec ⁻¹ is 100 to 10,000 mPa · s. A writing instrument comprising the oil-based ink composition for a writing instrument according to any one of claims 1 to 6. 8. A ballpoint pen tip that rotatably holds a ball is provided at the tip of the ink container, and the oil-based ink composition for a writing instrument according to any one of claims 1 to 7 is accommodated in the ink container. An oil-based ballpoint pen.