JP2013028788A - Ink composition for oil-based ballpoint pen, and oil-based ballpoint pen refill using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition for an oil-based ballpoint pen, which has excellent temporal ink stability and excellent writing performance, gives a thick writing density, has excellent light resistance, maintains lubricating ability even under a high writing pressure (a writing load of 400 gf) and suppresses the abrasion of a ball seat; and to provide an oil-based ballpoint pen refill using the same.SOLUTION: The ink composition for an oil-based ballpoint pen at least includes: a salt-forming dye of an acid dye and an aromatic amine; a pigment; and an organic solvent. There is also provided the oil-based ballpoint pen refill using the same.

Description

  The present invention relates to an oil-based ballpoint pen ink composition and an oil-based ballpoint pen refill using the same. More specifically, the ink-based ballpoint pen refill is excellent in ink aging stability, writing quality, dark handwriting, light resistance, and high writing pressure (writing The present invention relates to an oil-based ballpoint pen ink composition having excellent lubricity even at a load of 400 gf) and an oil-based ballpoint pen refill using the same.

  Many oil ballpoint ink compositions have been proposed that use various dyes such as nigrosine dyes, basic dyes, acid dyes, and processed dyes as colorants in oil ballpoint ink compositions. Has been.

  As such an ink composition for oil-based ballpoint pens, various colorants are used, and those using a nigrosine dye include those disclosed in JP-A-5-320558, “oil-based black ink”, triallylmethane base. Japanese Patent Application Laid-Open No. 9-165542 “Oil Black Ink”, Japanese Patent Application Laid-Open No. 9-71745 “Oil Black Ink”, and basic dyes are used as the basic dyes. Japanese Patent Application Laid-Open No. 8-134393, “Black Ink Composition for Oil-Based Ballpoint Pens”, etc.

"JP-A-5-320558" "JP-A-9-165542" "Japanese Patent Laid-Open No. 9-71745" "JP-A-8-134393"

  However, in Patent Document 1, when a nigrosine dye is used as a colorant, the concentration is high, the cost is low, and it is conventionally used. However, since it is poorly soluble in an organic solvent, there is a problem in ink aging stability. was there.

  Further, in Patent Documents 2 and 3, when a salt formation dye of triallylmethane basic dye and azo yellow acid dye is used as a colorant, a part of the salt formation dye collapses and precipitates over time. There were problems with the generation of things and poor writing.

  In Patent Document 4, a salt-forming dye based on a basic dye as a colorant has good ink aging stability, but newly contains a surfactant and the like in order to improve the writing quality. By doing so, the writing quality can be improved, but there is a problem that the surfactant reacts with the dye and precipitates are generated, which is a concern.

  Further, in Patent Documents 1 to 4, an improvement in light resistance and a darker handwriting are now more demanded.

  An object of the present invention is to provide an oil-based ballpoint pen ink composition having excellent ink aging stability, excellent writing quality, dark handwriting, good light resistance, and excellent lubricity even under high writing pressure (writing load 400 gf). It is to provide an oil-based ballpoint pen refill used.

In order to solve the above problems, the present invention
“1. An oil-based ballpoint pen ink composition comprising at least a salt-forming dye of an acid dye and an aromatic amine, a pigment, and an organic solvent.
2. 2. The ink composition for oil-based ballpoint pens according to item 1, wherein the aromatic amine is a quaternary amine.
3. 3. The oil-based ballpoint pen according to claim 1 or 2, wherein the aromatic ring amine is at least one selected from benzoxonium compounds, alkyldimethylbenzylammonium compounds, and alkyldiethylbenzylammonium compounds. Ink composition.
4). The ink composition for oil-based ballpoint pens according to any one of Items 1 to 3, wherein the acidic dye has a sulfo group.
5. The ink composition for oil-based ballpoint pens according to any one of Items 1 to 4, wherein the acid dye is a triallylmethane acid dye or an azo acid dye.
6). 6. The oil-based ballpoint pen ink composition according to any one of items 1 to 5, wherein the oil-based ballpoint pen ink composition contains a polyvinyl butyral resin.
7). 7. The oil-based ballpoint pen ink composition according to any one of items 1 to 6, wherein the oil-based ballpoint pen ink composition contains a phosphate ester-based surfactant.
8). 8. The oil-based ballpoint pen ink composition according to any one of items 1 to 7, wherein the oil-based ballpoint pen ink composition contains fine particles.
9. The ink composition for oil-based ballpoint pens according to any one of items 1 to 8, wherein the pH of the ink composition for oil-based ballpoint pens is 4 to 10.
10. The ink composition for oil-based ballpoint pens according to any one of items 1 to 9, wherein the ink viscosity at 20 ° C. and a shear rate of 500 sec ⁻¹ is 10 to 5000 mPa · s.
11. An oil-based ballpoint pen refill in which the ink composition for oil-based ballpoint pens according to any one of Items 1 to 10 is directly stored in the ink storage cylinder, the bottom wall of the ball holding chamber Is provided with a curved contact surface having a curvature different from the curvature of the ball, and the ball is in contact with a contact portion which is a part of the contact surface, A first gap that gradually decreases from the ink circulation hole side from the ink circulation hole side to the abutting portion is formed between the ball and the abutting surface, and the first gap from the tip side of the ink circulation groove is formed. The oil-based ballpoint pen refill is characterized in that a second gap that gradually decreases from the front end side of the ink circulation groove to the contact portion is formed.
12 12. The oil-based ballpoint pen refill according to any one of claims 1 to 11, wherein a lubricating coating layer is provided on the surface of the ball and / or on the surface of the contact surface.
13. A part of the ball protrudes from the tip end of the tip of the ink containing cylinder and is held rotatably, and is pressed forward by a coil spring, and has a valve mechanism at the inner wall of the ball and tip end. A ballpoint pen tip is mounted directly or via a tip holder, and the ink composition for oil-based ballpoint pens according to any one of Items 1 to 12 is directly packed in the ink containing cylinder. Oil-based ballpoint pen refill. "

  In the present invention, the dyes and pigments are stable in the ink, the writing quality is excellent, the handwriting is dark, the light resistance is good, the lubricity is maintained even under high writing pressure (writing load 400 gf), and the wear of the ball seat is suppressed. An oil-based ballpoint pen ink composition and an oil-based ballpoint pen refill using the same can be provided.

1 is a longitudinal sectional view showing a ballpoint pen tip of Example 1. FIG. FIG. 3 is an enlarged vertical sectional view of a principal part, partially omitted, showing the ball-point pen tip of Example 1. It is a figure which shows the ball-point pen refill using the ball-point pen tip of Example 1. FIG.

  The feature of the present invention is that a salt-forming dye of an acidic dye and an aromatic amine and a pigment are used in combination in the ink composition for an oil-based ballpoint pen. This is because the acid dye is neutralized with an aromatic amine to form a salt-forming dye, and when the ionic bond strength between the acid dye and the aromatic amine is increased, the ink aging stability for a long period of time in the oil-based ink is increased. This is because it can be estimated that it can be maintained.

  The aromatic amine used in the present invention is an amine having an aromatic ring such as a benzene ring, a naphthalene ring, and an anthracene ring, and the writing quality can be improved by having the aromatic ring. This is presumed that the aromatic ring has an effect of suppressing metal contact between the ball and the chip body by forming a lubricating film that is easily adsorbed to the metal chip, improving lubricity and improving writing quality. To do. Therefore, in the present invention, the use of a salt-forming dye of an acid dye and an aromatic amine makes it possible to improve ink aging stability and writing quality, and therefore is essential. Therefore, unlike the conventional case, the salt-forming dye can have both the effects of the colorant and the lubricant.

  However, if the salt-forming dye is used alone, the handwriting becomes thin. Therefore, it is necessary to use a pigment in combination. By using a pigment in combination, a dark handwriting that was difficult to obtain with the salt-forming dye alone can be obtained, and at the same time, light resistance can be improved. In addition, by using the pigment, it is possible to improve the lubricity by suppressing the metal contact by the pigment particles entering the gap between the ball and the ball seat. Furthermore, as described above, the lubricating layer is formed by the aromatic amine, but the lubricity is improved by further suppressing metal contact by the interaction between the lubricating layer of the aromatic amine and the pigment particles, It is possible to improve the writing taste.

  In addition, examples of aromatic amines include primary amines, secondary amines, tertiary amines and quaternary amines. In order to sufficiently neutralize acidic dyes, a more stable salt-forming dye is produced. It is preferable to use an aromatic quaternary amine.

  Aromatic quaternary amines include benzoxonium compounds (Benzoxonium), alkyldimethylbenzylammonium compounds, alkyldiethylbenzylammonium compounds, and the like. In consideration, benzoxonium compounds are preferred. Specifically, as benzoxonium compounds (Benzoxonium), benzylbistetradecylammonium compounds (Benzylbis (2-hydroxypropyl) tetradecylammonium), benzyldodecylbisammonium compounds (Benzyldodecylbis (2-hydroxypropyl) ammonium), benzyldecylbisammonium compounds (Benzyldecylbis (2-hydroxypropyl) ammonium) and the like, and examples of the alkyldimethylbenzylammonium compound include a tetradecyldimethylbenzylammonium compound, a hexadecyldimethylbenzylammonium compound, an octadecyldimethylbenzylammonium compound, and a palm alkyldimethylbenzylammonium compound. Examples of the alkyldiethylbenzylammonium compound include dodecyldiethylbenzylammonium compound. You may use these individually or in mixture of 2 or more types.

Examples of the acid dye used in the present invention include those having a sulfo group (—SO ₃ H), a carboxyl group (—COOH), and the like. Acid dyes having ₃ H) are preferred. This is because if a sulfo group (—SO ₃ H) is included, it is easy to form a strong lubricating layer between the ball and the ball seat, and therefore it is considered that the lubricity is likely to be improved. This is because a good lubricating effect can be obtained.

  In addition, acid dyes include triallylmethane acid dyes, azo acid dyes, anthraquinone acid dyes, and oxazine acid dyes. In view of the above, it is preferable to use a triallylmethane acid dye or an azo acid dye, most preferably an azo acid dye.

  Specific examples of the acid dye include C.I. I. Acid Black 1, 2, 7, 16, 17, 24, 26, 28, 31, 41, 48, 52, 58, 60, 63, 94, 107, 109, 112, 118, 119, 121, 122, 131, 155, 156; C.I. I. Acid Yellow 1,3,4,7,11,12,13,14,17,18,19,23,25,29,34,36,38,40,41,42,44,49,53,55, 59, 61, 71, 72, 76, 78, 79, 99, 111, 114, 116, 122, 135, 142, 161, 172; I. Acid Orange 7, 8, 10, 19, 20, 24, 28, 33, 41, 45, 51, 56, 64; I. Acid Red 1, 4, 6, 8, 13, 14, 15, 18, 19, 21, 26, 27, 30, 32, 34, 35, 37, 40, 42, 51, 52, 54, 57, 80, 82, 83, 85, 87, 88, 89, 92, 94, 97, 106, 108, 110, 111, 114, 115, 119, 129, 131, 133, 134, 135, 143, 144, 152, 154 155,172,176,180,184,186,187,249,254,256,289,317,318; C.I. I. Acid Violet 7, 11, 15, 17, 34, 35, 41, 43, 49, 51, 75; I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 27, 29, 40, 41, 43, 45, 49, 51, 53, 55, 56, 59, 62, 78, 80, 81, 83, 90, 92, 93, 102, 104, 111, 113, 117, 120, 124, 126, 138, 145, 167, 171, 175, 183, 229, 234, 236, 249; I. Acid Green 3, 9, 12, 16, 19, 20, 25, 27, 41, 44; I. Acid brown 4,14 etc. are mentioned. Examples of triallylmethane acid dyes and azo acid dyes include C.I. I. Acid Violet 17, C.I. I. Acid Blue 90, C.I. I. Acid Blue 9, C.I. I. Acid Yellow 36, C.I. I. Acid Yellow 42, C.I. I. Acid Red 97 and the like.

  Further, if the content of the salt-forming dye of the acid dye and aromatic amine is less than 0.1% by mass with respect to the total amount of the ink composition, it is difficult to obtain desired lubricity, and 40.0% by mass is obtained. If exceeding, the ink aging tends to become unstable, so 0.1 to 40.0% by mass is preferable with respect to the total amount of the ink composition. More preferably, it is 1.0-30.0 mass% with respect to the ink composition whole quantity, Most preferably, it is 5.0-20.0 mass%.

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 DPP Quinophthalone, selenium, triphenylmethane, perinone, perylene, goxazine, metallic pigment, pearl pigment, fluorescent pigment, phosphorescent pigment and the like. These pigments easily enter the gap between the ball and the ball seat, thereby suppressing metal contact and improving lubricity. In consideration of the interstices inside the chip, the average particle size is preferably 300 nm or less. More preferably, it is 150 nm or less. Here, the average particle diameter is an average particle diameter d measured by a particle size distribution meter.
That's 50. These pigments may be used alone or in combination of two or more. As for content of a coloring agent, 1.0-15.0 mass% is preferable with respect to the ink composition whole quantity. This is because if it is less than 1.0% by mass, it tends to be difficult to obtain a dark handwriting, and if it exceeds 15.0% by mass, it tends to aggregate in the ink. 3.0 to 10.0% by mass is most preferable.

  Examples of the pigment dispersant include polyvinyl butyral resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, polyvinyl pyrrolidone, and the like, and one or more of these can be used. Among them, polyvinyl butyral resin is preferable, because it is easy to disperse quickly and finely in an organic solvent, and the polyvinyl butyral resin is easily adsorbed to the pigment, so that it is easy to maintain long-term dispersion of the pigment. is there. In particular, among the pigments, basic carbon black is preferable in consideration of pigment dispersibility with the polyvinyl butyral resin. Here, the basic carbon black is defined as a basic carbon black having a pH value of 7 or more obtained by dispersing carbon black particles in ion exchange water having a pH of 7 and measuring the pH at 25 ° C. with a pH meter.

  The polybutyral resin is obtained by reacting polyvinyl alcohol (PVA) with butyraldehyde (BA), and the polyvinyl butyral resin preferably has 20 to 40 mol% of hydroxyl groups in the molecule. This is because if it is less than 20 mol%, it tends to be difficult to dissolve in an alcohol-based organic solvent, and if it exceeds 40 mol%, the water resistance tends to be inferior, and more preferably 30-40 mol%. preferable. In view of solubility in an organic solvent, the molecular weight is preferably 100,000 or less, and more preferably 30000 or less.

  If the content of the pigment dispersant is less than 0.1% by mass, the pigment dispersibility tends to be inferior, and if it exceeds 20.0% by mass, the solubility in the ink tends to be inferior and the ink viscosity tends to increase. The total amount of the ink composition is preferably 1.0 to 20.0% by mass, and more preferably 3.0 to 10.0% by mass in consideration.

  Furthermore, in order to maintain lubricity even under high writing pressure (writing load 400 gf) and suppress wear of the ball seat, it is preferable to use a phosphate ester-based surfactant. This is because the phosphoric acid group is easily adsorbed on the metal chip, so that the lubricity is easily improved. In particular, as in the present invention, when a salt-forming dye of an acid dye and an aromatic amine and a pigment are used in combination, a lubricating layer is formed by the aromatic amine as described above. It is easy to form a stronger lubricating layer, and it is easier to maintain lubricity even under high writing pressure (writing load of 400 gf) by suppressing metal contact by interaction with pigment particles.

  Phosphate ester surfactants include polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphate monoester, polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphate diester, polyoxyethylene alkyl ether Or polyoxyethylene alkylaryl ether phosphate triesters, alkyl phosphate esters, alkyl ether phosphate esters or derivatives thereof. These phosphate ester surfactants may be used alone or in combination of two or more. May be used. Among them, it is preferable to have at least an alkyl group having 5 to 18 carbon atoms. If the carbon number is less than 5, the lubricity tends to be insufficient under high writing pressure (writing load 400 gf). This is because if the number exceeds 18, the ink aging stability tends to be affected, and in view of the tendency, the carbon number of 8 to 15 is most preferable.

  Further, if the content of the phosphate ester-based surfactant is less than 0.1% by mass relative to the total amount of the ink composition, the desired lubricity tends to be difficult to obtain, and if it exceeds 5.0% by mass. In addition, since ink aging tends to be unstable, 0.1 to 5.0% by mass is more preferable with respect to the total amount of the ink composition. Most preferably, it is 0.5 to 3.0 mass% with respect to the total amount of the ink composition.

  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 ethers such as methoxybutanol, 3-methoxy-3-methylbutanol, glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, ethylene glycol, benzyl alcohol, methanol, ethanol, 1-propanol, 2-pro For oil-based ballpoint pens such as alcohols such as diol, isopropanol, isobutanol, t-butanol, propargyl alcohol, allyl alcohol, 3-methyl-1-butyn-3-ol, ethylene glycol monomethyl ether acetate and other higher alcohols The solvent generally used as ink can be illustrated. Among these, it is preferable to use at least an alcohol solvent in view of the dissolution stability of the acid dye and the salt-forming dye of the aromatic amine and the ink aging stability with the pigment. Furthermore, aromatic alcohol such as benzyl alcohol is most preferably used because it has an effect of improving lubricity. These organic solvents can use 1 type (s) or 2 or more types. The content of the solvent is preferably 10.0 to 65.0% by mass with respect to the total amount of the ink composition in consideration of the solubility of the colorant, handwriting drying property, bleeding, and the like.

  Further, as in the present invention, in an oil-based ballpoint pen ink composition that uses a salt-forming dye of an acidic dye and an aromatic amine and a pigment in combination, fine particles may be used in order to further improve the lubricity. This is because the fine particles can improve the lubricity by suppressing the metal contact by entering the fine particles into the gap between the ball and the ball seat, like the pigment. Specific examples of the fine particles include resin fine particles such as acrylic, silicone, and polyethylene, alumina fine particles, and silica fine particles. Among these, spherical silica fine particles are preferable. The fine particles are preferably fine particles having an average particle diameter of 5 to 100 nm in consideration of lubricity, and the average particle diameter is a median diameter, and can be determined by a centrifugal sedimentation method, a laser diffraction method, a BET method, or the like.

Furthermore, when the oil-based ballpoint pen ink of the present invention is further used in combination with an organic amine having ethylene oxide (CH ₂ CH ₂ O) in addition to the aromatic amine, a lubricating effect is easily obtained. Therefore, it is preferable to use oxyethylene alkylamine or polyoxyethylene alkylamine having ethylene oxide (CH ₂ CH ₂ O). You may use these individually or in mixture of 2 or more types.

Specific examples of the oxyethylene alkylamine and polyoxyethylene alkylamine include Naimine L-201, Naimine L-202, L-207, S-202, S-204, S-210, and T. ₂ -206, the S-210, the DT-203, the DT-208, Nymeen L-207, the T ₂ -206, the DT-208 (NOF Co., Ltd.). The content of the oxyethylene alkylamine and polyoxyethylene alkylamine is preferably 0.1 to 10.0% by mass, more preferably 1%, based on the total amount of the ink composition, considering lubricity and stability over time. 0.0 to 5.0% by mass.

  Moreover, when using together the salt-forming dye of the said acid dye and the salt-forming dye of an aromatic amine, and a pigment like this invention, when a nib dries, write-out performance will deteriorate easily. Therefore, it is preferable to use a fatty acid because a soft film can be formed and the writing performance is easily improved. Among them, it is preferable to use oleic acid.

  Further, when the oil-based ballpoint pen ink composition newly contains a salt-forming dye of an acid dye and an aromatic amine as in the present invention, the ink aging stability can be maintained by, for example, moisture absorption during production or aging. In addition, since water is contained in the oil-based ink, it is preferable to pay attention to the pH value. In the present invention, a pH value of 3.9 or less is a strongly acidic region, a pH value of 10.1 or more is a strongly alkaline region, and a pH value of 4.0 to 10.0 is an intermediate region between a strongly acidic region and a strongly alkaline region (weak Acid, neutral, weakly alkaline).

  In order to maintain the ink aging stability of the oil-based ballpoint pen ink composition, it is preferable that the pH value is in the neutral range of 4.0 to 10.0. This is because if the pH value is 3.9 or less, the metal ions in the chip body are likely to elute, so metal salt precipitates are likely to occur with the salt-forming dye, and if the pH value is 10.1 or more, This is because the ionic bond of the salt-forming dye tends to be separated, so that there is a tendency that the ink aging stability and the color tone are easily affected, and further the pigment dispersion stability cannot be obtained. Furthermore, considering the ink aging stability, the pH value is preferably 5.0 to 9.0.

  The pH value in the present invention is a method for measuring an ink composition for oil-based ballpoint pens, in which oil-based ink is collected in a container, ion-exchanged water is added, heated with stirring, allowed to cool after heating, After replenishing the amount of water evaporated, filter using filter paper. Using the upper layer of the filtered filtrate, pH measurement shows a value measured at 20 ° C. using an IM-40S type pH meter manufactured by Toa DKK Corporation.

The ink viscosity of the oil-based ballpoint pen ink composition of the present invention is not particularly limited. However, when the ink viscosity at 20 ° C. and a shear rate of 500 sec ⁻¹ is less than 10 mPa · s, bleeding or ink sag occurs in the handwriting. In addition, if the ink viscosity at 20 ° C. and a shear rate of 500 sec ⁻¹ exceeds 5000 mPa · s, the ball rotation resistance during writing tends to increase, and the writing taste tends to become heavy. Therefore, the ink viscosity at 20 ° C. and a shear rate of 500 sec ⁻¹ is preferably 10 to 5000 mPa · s. More preferably, it is 50-3,000 mPa * s, Most preferably, it is 100-1500 mPa * s which is easy to improve a writing taste.

  Further, as the colorant, in addition to the above-mentioned salt-forming dyes of acid dyes and aromatic amines, pigments, oil-soluble dyes, acid dyes, basic dyes, metal-containing dyes, and various salt-forming types thereof. A dye or the like may be employed. Specifically, Bali First Black 1802, Bali First Black 1805, Bali First Black 1807, Bali First Violet 1701, Bali First Blue 1601, Bali First Blue 1605, Bali First Blue 1621, 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 RO6G-B, BASE OF BASIC DYES VPB-B, BASE OF BASIC DYES VB-B, BASEOF 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.C. 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 510, S.I. B. N. Yellow 530, S.I. R. C-BH (above, manufactured by Hodogaya Chemical Co., Ltd.) and the like.

  In addition, in order to improve lubricity, as surfactants, fluorine surfactants, silicone surfactants, fatty acid alkanolamides, anionic surfactants and / or cationic surfactants are used. As a viscosity modifier, ketone resins, terpene resins, alkyd resins, phenoxy resins, resins such as polyvinyl acetate, pseudoplasticizers such as fatty acid amide, hydrogenated castor oil, and colorant stability An agent, a plasticizer, a chelating agent, water, or the like may be used as appropriate. These may be used alone or in combination of two or more.

  When the oil-based ballpoint pen ink composition of the present invention is used in a ballpoint pen refill, its structure is not particularly limited, but the ink circulation formed in the chip body, in the center of the ball holding chamber and the bottom wall of the ball holding chamber It has a hole and a plurality of ink flow grooves extending radially from the ink flow hole, and by caulking the tip end portion inward, a part of the ball protrudes from the tip end edge and is held freely. An oil-based ballpoint pen in which the ballpoint pen tip is mounted directly on the tip of the ink containing cylinder or via a chip holder, and the salt dye and pigment of the acid dye and aromatic amine are used in the ink containing cylinder It can be used as an oil-based ballpoint pen refill that contains the ink composition directly. The structure of the ballpoint pen tip is not particularly limited, but considering the suppression of writing quality and wear of the tip body, the bottom wall of the ball holding chamber has a substantially circular arc with a different curvature from the ball. An ink flow hole is provided between the ball and the contact surface, from the ink flow hole side to the contact portion between the ball and the contact surface. It is preferable to form a first gap that gradually decreases from the side and a second gap that gradually decreases from the ink circulation hole side from the ball holding chamber side to the contact portion between the ball and the contact surface.

  This is because the first gap and the ball holding chamber side gradually decrease from the ink circulation hole side from the ink circulation hole side to the contact portion between the ball and the contact surface between the ball and the contact surface. By forming a second gap that gradually decreases from the ink circulation hole side to the contact portion between the ball and the contact surface, it is easy to make fluid lubrication or mixed lubrication between the ball and the contact surface. This is because it is easy to suppress wear and improve writing quality.

  Further, the relationship between the ball and the contact surface will be described in detail. The lubrication state of the oil-based ballpoint pen ink composition of the present invention by the rotation of the ball is the same as that of the oil-based ballpoint pen ink composition when the ball rotates. It is dragged from the hole into a narrow gap between the ball and the contact surface, and a layer of ink for ballpoint pen is formed between the ball and the contact surface. This ink layer generates pressure and generates a force to float the ball. It is presumed that it is easy to suppress the wear of the bottom wall because a wedge effect is obtained. In particular, in the case of an oil-based ink composition that uses a salt-forming dye and a pigment in combination with the acid dye and aromatic amine as in the present invention, it is formed by the interaction between the phenylsulfone group or the phenyl group of the salt-forming dye and pigment particles. It is presumed that it is effective in suppressing the wear of the bottom wall because a wedge effect is easily obtained by the elastic lubricating film layer.

  Further, the lubricating state of the oil-based ballpoint pen ink composition from the ink circulation hole due to the rotation of the ball is as described above, and when the ball rotates, the oil-based ballpoint ink composition is moved between the ball and the contact surface. Although drawn into a narrow gap, when writing, the oil-based ballpoint pen ink composition supplied to the contact surface from the ink circulation hole side and the oil-based ballpoint pen ink composition that could not protrude onto the paper surface There is a tendency to return to the contact surface from the chamber. Therefore, by forming the first gap and the second gap, the writing quality and the wear resistance can be easily improved synergistically.

  It is important that the shape of the contact surface is a curved surface having a curvature different from the curvature of the ball in order to form the first gap and the second gap between the ball and the contact surface. . Moreover, since the wedge effect tends to increase as the distance on the ink circulation hole side becomes smaller, it is preferable to make the gap on the ink circulation hole side smaller. Specifically, when the distance on the ink circulation hole side is longer than 5 μm with the length in the axial direction, the wedge effect is difficult to be obtained, so that it is preferably 5 μm or less, more preferably 0.001 μm to 3 μm, and 0.005 μm. Most preferably, the thickness is 001 μm to 1 μm. In addition, the contact surface is preliminarily arcuate and the first gap is gradually reduced from the ink circulation hole side to the contact portion, so that a high wedge is formed near the contact portion of the ball. Effectively, the force to float the ball is increased, wear of the contact surface can be effectively suppressed, and even if the contact surface is worn, rapid wear can be suppressed and the clearance relationship can be easily maintained. .

Next, a method for preparing a salt-forming dye of an acid dye and an aromatic amine will be described.
Formulation Example 1
First, 1000 g of water and 30 g of Acid Violet 17 (triphenylmethane acid dye) were weighed and heated in a beaker, dissolved using a disper stirrer, 60 g of benzoxonium compound was weighed and stirred. Filtration was performed using filter paper, and the residue on the filter paper was dried to obtain a salt-forming dye.

Next, an Example is shown and this invention is demonstrated.
The ink composition for oil-based ballpoint pens of Example 1 was prepared by dissolving the pigment dispersion resin with an organic solvent and a pigment dispersant at 50 ° C. using a mixing stirrer to prepare Solution A. A pigment is added to the obtained solution A, and a dispersion base is prepared using three rolls. The remaining components were stirred on this dispersion base at 50 ° C. using a mixing stirrer to obtain an ink composition for oil-based ballpoint pens. Specific blending amounts are as follows. Ink viscosity was measured at a shear rate of 500 sec ^-1 in an environment of 20 ° C. using AR-G2 (stainless steel 40 mm 2 ° rotor) manufactured by TA Instruments Inc., and 650 mPa · s. Met. Moreover, when pH value was measured, it was pH = 7.5.

Example 1
Formulation Example 1 Salt-forming dye 6.0% by mass
Salt-forming dye of Formulation Example 2 6.0% by mass
Formulation Example 3 Salt-Forming Dye 6.0% by Mass
Pigment (carbon black) 5.0% by mass
Pigment dispersant (polyvinyl butyral) 2.0% by mass
Organic solvent (benzyl alcohol) 57.8% by mass
Stabilizer (oleic acid) 1.0% by mass
Lubricant (polyoxyethylene alkylamine) 1.0% by mass
Resin (Polyvinylpyrrolidone) 0.2% by mass
Resin (ketone resin) 5.0% by mass

Formulation Examples 2-8
As shown in Table 1, the salt-forming dyes of Formulation Examples 2 to 8 were prepared in the same manner as Formulation Example 1 except that each component was changed, and used in Examples and Comparative Examples.

Examples 2-7, 9, 10
As shown in Tables 2 and 3, oil-based ballpoint pen ink compositions of Examples 2 to 10 were obtained in the same procedure as Example 1 except that each component was changed.
Example 8
As shown in Table 3, except that each component was changed, each component other than water was carried out in the same procedure as in Example 1. After cooling at room temperature, water was added and an oil ballpoint pen ink composition was obtained by disper stirring. It was.

Comparative Examples 1-6
As shown in Table 4, except that each component was changed, blending was carried out in the same procedure as in Example 1, and ink compositions for oil-based ballpoint pens of Comparative Examples 1 to 6 were obtained. Table 3 shows the measurement and evaluation results.

Testing and evaluation
The oil-based ballpoint pen ink composition 24 (0.4 g) and the grease-like ink follower 25 prepared in Examples 1 to 10 and Comparative Examples 1 to 6 were placed in an ink containing cylinder 22 (polypropylene) with a ball diameter of φ0. An oil-based ballpoint pen was manufactured by filling a ballpoint pen refill 21 equipped with a ballpoint pen tip 1 (stainless steel wire) holding a 7 mm ball 9 rotatably. The following tests and evaluations were performed using a writing paper JIS P3201 as a writing test paper.

  In the present invention, the ballpoint pen tip 1 having the structure shown in FIGS. The ball-point pen tip of FIGS. 1 and 2 is an ink circulation hole 7 in the center of the ball holding chamber 3 of the chip body 2 made of stainless steel wire, and the ink that extends radially from the ink circulation hole 7 and does not reach the tip rear hole 8. A substantially arcuate contact surface 5 having a curvature different from that of the ball 9 is provided on the bottom wall 4 in which the flow groove 6 is formed, and a tungsten carbide ball 9 having a diameter of 0.5 mm is placed on the contact surface 5. By crimping the tip end portion 2a inward, a part of the ball 9 is rotatably held so as to protrude from the tip end edge.

Such a ball-point pen tip 1 is manufactured as follows. That is, for example, a stainless steel wire having a diameter of 2.3 mm and a hardness of 230 Hv to 280 Hv is cut to a desired length, and the ball holding chamber 3, the ink circulation hole 7, and the ink circulation groove extending radially from the ink circulation hole 7. 6 is produced. Thereafter, hammering is performed from the tip end portion 2a side in a state where the ball 9 is placed on the bottom wall 4 of the ball holding chamber 3, and a curved surface having a larger radius of curvature than the ball 9 is formed by the springback property. The tip end 2a is caulked inward. As a result, a curved contact surface 5 having a curvature different from that of the ball 9 is formed, and the ball 9 is on the peripheral line around the axis on the tip end portion 2a side of the center position of the contact surface 5 in the axial direction. Contact is made at the contact portion 5a. As a result, a first gap S1 and a second gap S2 are formed between the ball 9 and the contact surface 5.

  By forming the first gap S1 and the second gap S2, it is easy to maintain the fluid lubrication or mixed lubrication between the ball 9 and the contact surface 5 (contact portion 5a). For this reason, the wear of the contact surface (contact portion) is suppressed. In the present embodiment, the length H of the opening in the axial direction on the ink circulation hole 7 side of the first gap S1 is 0.9 μm (see FIG. 2).

Ink aging test: The ink in the chip body was observed with a microscope.
Good without deposits ... ◎
Slightly generated precipitates ... ○
Precipitates are generated, but there are no practical problems.
Precipitates are generated, causing scumming or poor writing ・ ・ ・ ×

Written taste: A hand-written sensory test was performed and evaluated.
Very smooth ・ ・ ・ ◎
Smooth thing ○○
Somewhat heavy ・ ・ ・ △
Heavy thing

Pigment dispersibility test: The pigment dispersibility of the ink composition was observed with an optical microscope (manufactured by Olympus Corp.) at a magnification of 100 after 50 months at 80 ° C. and humidity of 80%.
Uniform pigment dispersion ... ◎
A pigment dispersed almost uniformly ・ ・ ・ ○
Pigment agglomeration was observed but there was no practical problem.
Pigment agglomerated ・ ・ ・ ×

Handwriting darkness: Handwritten handwriting was observed.
Thick and clear handwriting
What is a dark handwriting
A handwriting with a darkness that has no practical problem ・ ・ ・ △
Thin handwriting ・ ・ ・ ×

Light resistance test: A spiral writing test was conducted on JIS P3201 writing paper A under a writing angle of 70 ° and a writing load of 150 g at a writing speed of 4.5 m / min. Using (made by Suga Test Instruments Co., Ltd.), irradiation was performed until the blue scale faded to the third grade, and the handwriting was observed.
Does not fade or slightly fades ... ◎
Fading, but at a level where there is no practical problem ・ ・ ・ ○
Level where fading is conspicuous and causes practical problems ・ ・ ・ ×

High writing pressure writing test: The wear of the ball seat after the writing test was measured with a running tester with a load of 400 gf, a writing angle of 70 °, and 4 m / min.
Ball seat wear less than 5μm ・ ・ ・ ◎
Ball seat wear is 5 μm or more and less than 10 μm.
Ball seat wear is 10 μm or more and less than 20 μm, but can be written.
Wearing the ball seat is bad and results in poor writing ・ ・ ・ ×

  In Examples 1 to 10, good performance was obtained in all of the ink aging test, writing taste, pigment dispersibility, handwriting density, water resistance, and light resistance.

  In Comparative Examples 1 to 3, since no pigment was used, fading was conspicuous, light resistance was at a level that was a problem in practical use, and the darkness of the handwriting was also inferior. Furthermore, since the salt of the comparative example 2 and 3 acid dye and alkylamine was used, the writing taste was also heavy.

  In Comparative Examples 4 and 5, since a salt-forming dye of an acid dye and an alkylamine was used, the ink aging was not stable and the writing taste was heavy.

  In Comparative Example 6, since the acid dye was used alone, the ink aging stability was poor, and thus the ink could not be formed.

As in the present invention, in order to improve the writing quality, when the ink viscosity at 20 ° C. and the shear rate of 500 sec ⁻¹ is set in the range of 10 to 5000 mPa · s, a ballpoint pen is used to prevent the ink from dripping. The ball held rotatably at the tip of the tip is pressed against the inner wall of the tip end of the tip directly by a coil spring or via a pressing body, and the ink is applied to the inner wall of the tip end of the tip and the ball by the pressing force at the time of writing. It is preferable to provide a valve mechanism for allowing the chip to flow out, and to close the minute gap at the tip of the tip when not in use.

  In the present invention, by providing a lubricating coating layer on the surface of the ball and / or the surface of the contact surface, a synergistic effect between the lubricating coating layer and the fluid lubrication or mixed lubrication by the ink layer described above causes the ball and the inner wall of the chip. This is preferable because the contact resistance can be remarkably reduced and the wear resistance and writing feeling of the contact surface can be remarkably improved.

  The lubricating coating layer used in the present invention includes diamond-like carbon (DLC), tungsten disulfide (WS2), molybdenum disulfide (MoS2), graphite, fluorine-containing polymers such as tetrafluoroethylene (PTFE), silicone, and the like. Conventionally known solid lubricants such as resins can be used as appropriate. The method for coating the lubricating coating layer is not particularly limited, and examples thereof include vacuum deposition, ion deposition, physical vapor deposition, chemical vapor deposition, vacuum arc vapor deposition, and the like. May be. In particular, among the above-described lubricants, diamond-like carbon (DLC) is most preferably used in consideration of wear resistance and lubricity.

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

DESCRIPTION OF SYMBOLS 1 Ball-point pen tip 2 Tip body 2a Tip part 2b Seal surface 3 Ball holding chamber 4 Bottom wall 5 Contact surface 5a Contact part 6 Ink flow groove 7 Ink flow hole 8 Rear hole 9 Ball 21 Ball pen refill 22 Ink receiving cylinder 23 Coil Spring 24 Ballpoint pen ink 25 Ink follower S1, S2 Clearance

Claims (13)

An ink composition for oil-based ballpoint pens comprising at least a salt-forming dye of an acid dye and an aromatic amine, a pigment, and an organic solvent. The ink composition for oil-based ballpoint pens according to claim 1, wherein the aromatic amine is a quaternary amine. 3. The oil-based ballpoint pen ink according to claim 1, wherein the aromatic cyclic amine is at least one selected from a benzoxonium compound, an alkyldimethylbenzylammonium compound, and an alkyldiethylbenzylammonium compound. Composition. The ink composition for oil-based ballpoint pens according to any one of claims 1 to 3, wherein the acidic dye has a sulfo group. 5. The oil-based ballpoint pen ink composition according to claim 1, wherein the acid dye is a triallylmethane acid dye or an azo acid dye. 6. 6. The oil-based ballpoint pen ink composition according to any one of claims 1 to 5, wherein the oil-based ballpoint pen ink composition contains a polyvinyl butyral resin. The oil-based ballpoint pen ink composition according to any one of claims 1 to 6, wherein the oil-based ballpoint pen ink composition contains a phosphate ester surfactant. 8. The oil-based ballpoint pen ink composition according to any one of claims 1 to 7, wherein the oil-based ballpoint pen ink composition contains fine particles. The ink composition for oil-based ballpoint pens according to any one of claims 1 to 8, wherein the pH of the ink composition for oil-based ballpoint pens is 4 to 10. The ink composition for oil-based ballpoint pens according to any one of claims 1 to 9, wherein the ink viscosity at 20 ° C and a shear rate of 500 sec ^-1 is 10 to 5000 mPa · s. An oil-based ballpoint pen refill in which the ink composition for oil-based ballpoint pens according to any one of claims 1 to 10 is directly stored in the ink storage cylinder, wherein the bottom wall of the ball holding chamber has A curved contact surface having a curvature different from the curvature of the ball is provided, and the ball is in contact with a contact portion which is a part of the contact surface; A first gap gradually decreasing from the ink circulation hole side from the ink circulation hole side to the abutting portion is formed between the ink circulation hole side and the abutting surface. The oil-based ballpoint pen refill is characterized in that a second gap that gradually decreases from the front end side of the ink circulation groove to the portion is formed. The oil-based ballpoint refill according to any one of claims 1 to 11, wherein a lubricating coating layer is provided on the surface of the ball and / or on the surface of the contact surface. A part of the ball protrudes from the tip end of the tip of the ink containing cylinder and is held in a rotatable manner, and is pressed forward by a coil spring, and has a valve mechanism at the inner wall of the ball and tip end of the tip. The ball-point pen tip which is formed directly or through a chip holder is mounted, and the oil-based ball-point pen ink composition according to any one of claims 1 to 12 is directly packed in the ink containing cylinder. Ballpoint refill.

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