JP2022013748A - Ink composition for writing instrument, and writing instrument using the same - Google Patents

Abstract

To provide an ink composition for a writing instrument, exhibiting thickening action effect, suppressing ink leakage, making writing feel excellent, suppressing blurred writing, and excellent in writing property due to containing a thixotropy-imparting agent enabling stable thickening action without being inhibited in thickening by an ionic material (metallic ion or the like), unlike a conventional a thixotropy-imparting agent, and to provide a writing instrument using the same.SOLUTION: An ink composition for a writing instrument contains a coloring agent, a solvent, and an (acrylic acid/acrylic acid perfluoroalkyl) copolymer. A writing instrument using the same is also provided.SELECTED DRAWING: None

Description

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

Conventionally, water-based ink compositions and oil-based ink compositions have been used as ink compositions for writing tools, but especially for ballpoint pens, water-based ballpoint pens filled with water-based ink compositions and oil-based ballpoint pen compositions filled with oil-based ink compositions have been used. Among them, there is known a gel ink composition in which a shear-reducing viscosity is imparted to an ink composition, and various proposals have been made regarding the shear-reducing viscosity-imparting agent.

As a shear thinning agent, polysaccharides such as xanthan gum, welan gum, and daiyutan gum have been proposed for water-based ink compositions, and fatty acid amide wax, hydrogenated castor oil, etc. have been proposed for oil-based ink compositions. Has been done.

As a technique using xanthan gum, welan gum, and Daiyutan gum as such an ink composition for writing instruments, Japanese Patent Publication No. 64-8673 "Oil-based ink composition for writing instruments" and JP-A-4-214782 "Aqueous ballpoint pen". "Ink Composition for Ink", Japanese Patent Application Laid-Open No. 2005-068363 "Aqueous Ink Composition and Aqueous Ballpoint Pen Using It", and Japanese Patent Laid-Open No. 7-196972 for techniques using fatty acid amide wax and hydrogenated castor oil. , Japanese Patent Application Laid-Open No. 7-268268.

"Special Publication No. 64-8673" "Japanese Patent Laid-Open No. 4-214782" "Japanese Patent Laid-Open No. 2005-068363" "Japanese Patent Laid-Open No. 7-196972" "Japanese Patent Laid-Open No. 7-268268"

In Patent Documents 1 to 3, shear de-viscosity can be imparted and a certain degree of thickening effect can be obtained, but the type of colorant, the type of surfactant, other ink components, and ballpoint pen chips. Depending on the metal material of the above, an ionic substance (metal ion or the like) present in the ink tends to cause thickening inhibition, and a desired thickening effect may not be obtained.
Further, in Patent Documents 4 and 5, hydrogenated castor oil and fatty acid amide wax can obtain a certain degree of thickening effect, but the ink viscosity at rest becomes high, which affects the writing quality and ink. The followability was apt to be inferior, and the brush strokes may be blurred, so there was room for improvement.

An object of the present invention is that, unlike a conventional shear-reducing viscosity-imparting agent, an ionic substance (metal ion or the like) can perform a stable thickening action without inhibiting the thickening. An ink composition for writing instruments having excellent writing performance, which has a thickening effect, suppresses ink leakage, improves writing quality, and suppresses handwriting blurring by containing an imparting agent, and a writing instrument ink composition thereof were used. To get a writing instrument.

４．前記（アクリル酸／アクリル酸パーフルオロアルキル）共重合体が、一般式（化２）で示されるアクリル酸を構成成分とすることを特徴とする第１項ないし第３項のいずれか１項に記載の筆記具用インキ組成物。

５．前記（アクリル酸／アクリル酸パーフルオロアルキル）共重合体が、架橋剤を構成成分とすることを特徴とする第１項ないし第４項のいずれか１項に記載の筆記具用インキ組成物。
６．前記筆記具用インキ組成物に、界面活性剤を含んでなることを特徴とする第１項ないし第５項のいずれか１項に記載の筆記具用インキ組成物。
７．前記筆記具用インキ組成物に、樹脂粒子を含んでなることを特徴とする第１項ないし第６項のいずれか１項に記載の筆記具用インキ組成物。
８．第１項ないし第７項のいずれか１項に記載の筆記具用インキ組成物を収容してなることを特徴とする筆記具。」とする。 The present invention is to solve the above problems.
"1. An ink composition for writing utensils, which comprises a colorant, a solvent, and a (acrylic acid / perfluoroalkyl acrylate) copolymer.
2. 2. The writing tool according to Item 1, wherein the content of the (acrylic acid / perfluoroalkyl acrylate) copolymer is 0.1 to 10% by mass with respect to the total amount of the ink composition. Ink composition.
3. 3. The writing tool according to item 1 or 2, wherein the (acrylic acid / perfluoroalkyl acrylate) copolymer contains an acrylic acid ester represented by the general formula (Chemical Formula 1) as a constituent component. Ink composition.

4. Item 1. The item 1 to item 3 is characterized in that the (acrylic acid / perfluoroalkyl acrylate) copolymer contains acrylic acid represented by the general formula (Chemical Formula 2) as a constituent component. The described ink composition for writing tools.

5. The ink composition for writing tools according to any one of Items 1 to 4, wherein the (acrylic acid / perfluoroalkyl acrylate) copolymer contains a cross-linking agent as a constituent component.
6. The ink composition for writing tools according to any one of Items 1 to 5, wherein the ink composition for writing tools contains a surfactant.
7. The ink composition for writing tools according to any one of Items 1 to 6, wherein the ink composition for writing tools contains resin particles.
8. A writing tool comprising the ink composition for a writing tool according to any one of paragraphs 1 to 7. ".

The present invention contains a colorant, a solvent, and a (acrylic acid / perfluoroalkyl acrylate) copolymer, so that the gel structure is stable even in the presence of ionic substances (metal ions, etc.) in the ink. Ink leakage from the gap at the tip of the writing (in the case of a ball pen, ink leakage from the gap between the ball and the tip of the tip) is suppressed by imparting shear reduction viscosity and increasing the ink viscosity at rest. However, by lowering the ink viscosity at the time of writing, it was possible to obtain an ink composition for writing tools having good writing quality, suppressing brush strokes, and having excellent writing properties, and a writing tool using the same.

A feature of the present invention is that the ink composition for writing tools contains a colorant, a solvent, and a (acrylic acid / perfluoroalkyl acrylate) copolymer.

By containing a colorant, a solvent, and a (perfluoroalkyl acrylate / perfluoroalkyl acrylate) copolymer in the ink composition for writing tools, it has a stable gel structure in the ink and imparts shear reduction viscosity. However, it was found that ink leakage from the gap at the tip of the writing was suppressed, the writing quality was improved, the writing scratches were suppressed, and the writing performance was excellent.

((Acrylic acid / Perfluoroalkyl acrylate) copolymer)
Regarding the (acrylic acid / perfluoroalkyl acrylic acid) copolymer used in the present invention, at least a structural unit derived from acrylic acid ester and acrylic acid (methacrylic acid) containing acrylic acid ester and acrylic acid (methacrylic acid) as constituent components. It is a copolymer having a structural unit derived from (acid).
(Acrylic acid / Perfluoroalkyl acrylate) The copolymer contains perfluoroalkyl acrylate (acrylic ester having a fluorine atom), which is different from the conventional shear reducing viscosity imparting agent, and therefore the ions in the ink. It is presumed that a stable network structure can be formed and a gel structure can be formed without being hindered by a sex substance (metal ion), and the ink viscosity can be increased.
Therefore, by forming a stable network structure and forming a gel structure, the ink viscosity at rest can be set high, and by suppressing the flow of ink, the gap at the tip of the writing can be used (in the case of a ballpoint pen). Ink leakage from the gap between the ball and the tip of the tip) By suppressing the ink from seeping out, the effect of suppressing ink leakage from the gap at the tip of the writing (ink leakage from the gap between the ball and the tip of the tip) can be obtained. Furthermore, since it has a weak network structure, the gel structure is temporarily melted by an impact such as shearing during writing, so that the ink viscosity is lowered and the writing quality can be kept good. In particular, when it is used for a ballpoint pen, it is presumed that an effect of easily improving the writing taste can be obtained by an impact such as shearing of a ball at the time of writing, and it is effective when used as an ink composition for a ballpoint pen, which is preferable. ..
The (acrylic acid / perfluoroalkyl acrylate) copolymer is preferably a (acrylic acid / perfluoroalkyl acrylate) crosspolymer. This is effective and preferable because it is easy to form a three-dimensional network structure by using the cross polymer, and it is easy to form a more stable gel structure by using a denser three-dimensional network structure. In particular, it is preferable to use it as an ink composition for a ballpoint pen because it is effective.
Further, when a pigment is used as the colorant, it can be more preferably used because the gel structure makes it easy to maintain the dispersibility of the pigment, which is preferable.

The (acrylic acid / perfluoroalkyl acrylate) copolymer contains the acrylic ester represented by the general formula (Chemical Formula 1) as a constituent component of the perfluoroalkyl acrylate (acrylic ester having a fluorine atom). It is preferable to be. This is because even if ionic substances (metal ions, etc.) such as colorants and surfactants are present in the ink components, unlike conventional shear de-viscosity imparting agents, acrylic esters having fluorine atoms are a constituent component. Therefore, it is possible to increase the viscosity of the ink by forming a stable network structure and forming a gel structure without being hindered from thickening, and by setting the ink viscosity at rest to a high value, it is possible to increase the viscosity of the ink. The effect of suppressing ink leakage from the gap at the tip of the writing (ink leakage from the gap between the ball and the tip of the tip) and the weak network structure allow the gel structure to temporarily dissolve due to impact such as shearing during writing. This is because the viscosity of the ink is lowered and the writing quality can be kept good.

Further, for the acrylic ester represented by the general formula (Chemical Formula 1), which is a constituent component of the (acrylic acid / perfluoroalkyl acrylate) copolymer, the ink viscosity is stably increased by forming a stable network structure. Considering that it is easy to carry out, _RA is preferably a hydrogen atom, m is preferably 2 to 4, preferably 2 to 3, and further preferably 2.

Specific examples of the acrylic acid ester represented by the general formula (Chemical Formula 1) include 2-perfluorohexyl ethyl (meth) acrylate, 3-perfluorohexylpropyl (meth) acrylate, and 4-perfluorohexyl butyl (4-perfluorohexyl butyl (meth) acrylate). Meta) Acrylate and the like can be mentioned. In the embodiment described above, (meth) acrylate means acrylate and / or methacrylate.
Further, among the acrylic acid esters represented by the general formula (Chemical Formula 1), it is preferable to form a more stable network structure because it is easy to suppress ink leakage from the gap at the tip of writing and maintain good writing quality. .. 2-Perfluorohexyl ethyl (meth) acrylate is preferable, and 2-perfluorohexyl ethyl acrylate is preferable if more consideration is given.

Further, for the (acrylic acid / perfluoroalkyl acrylate) copolymer, it is preferable that the constituent component of acrylic acid contains acrylic acid represented by the general formula (Chemical Formula 2). This is because it is easy to form a more stable network structure and a weak network structure, so that it is easy to suppress ink leakage from the gap at the tip of writing and to maintain good writing quality. In particular, it is preferable to use it as an ink composition for a ballpoint pen because it is effective. Further, considering the above _- mentioned effects, the RB of the general formula (Chemical formula 2) is preferably a hydrogen atom or an alkyl having 1 to 3 carbon atoms, and further considering the general formula (Chemical formula 2). _RB is preferably a hydrogen atom or an alkyl having 1 carbon atom, and considering that it is easy to form a more stable network structure, the _RB of the general formula (formulation 2) is a hydrogen atom. Is preferable. Specific examples of the acrylic ester represented by the general formula (Chemical formula 2) include acrylic acid and methacrylic acid. Acrylic acid and methacrylic acid are preferable in consideration of the above-mentioned effects, and acrylic acid is more preferable. Acrylic acid is preferred.

As for the (acrylic acid / perfluoroalkyl acrylate) copolymer used in the present invention, since the above-mentioned effects can be easily obtained, at least the acrylic acid ester represented by the general formula (Chemical formula 1) and the general formula (Chemical formula 2) are used. It is preferable to use a copolymer containing acrylic acid represented by the above formula as a constituent component, and in order to obtain the effect more easily, at least the acrylic acid ester represented by the general formula (Chemical formula 1) and the general formula (Chemical formula 2) are used. ) Is preferably used as a constituent cross-polymer. This is because it is easy to form a three-dimensional network structure, and by making it a denser three-dimensional network structure, it is easier to form a more stable gel structure, and it is particularly effective when used as an ink composition for a ballpoint pen. Therefore, it is preferable.
In addition, the ratio (weight ratio) of acrylic acid ester (chemical 1) and acrylic acid (chemical 2) is (chemical 1) in consideration of ink viscosity increase (ink viscosity development) and stability in ink. / (Chemical formula 2) = 0.1 to 1, more preferably (Chemical formula 1) / (Chemical formula 2) = 0.1 to 0.5, and most preferably 0.15 to 0.4.

As the constituent component of the (acrylic acid / perfluoroalkyl acrylate) copolymer used in the present invention, it is preferable to include a cross-linking agent as a constituent component in addition to the above-mentioned acrylic acid and perfluoroalkyl acrylate. This is because the inclusion of a cross-linking agent facilitates cross-linking between acrylic acid and perfluoroalkyl acrylate, which facilitates ink thickening (ink viscosity development) and further forms a stable network structure. This is because the effect of the present invention can be easily obtained. In particular, it is preferable to prepare a copolymer containing acrylic acid ester (chemical 1), acrylic acid (chemical 2), and a cross-linking agent as constituent components, and acrylic acid ester (chemical 1), acrylic acid (chemical 2), and acrylic acid (chemical 2). It is preferable to use a cross-polymer containing a cross-linking agent as a constituent component, which facilitates the formation of a three-dimensional network structure and facilitates the formation of a more stable gel structure by forming a denser three-dimensional network structure. This is because it is particularly effective when used as an ink composition for a ball pen, and is therefore preferable.

Examples of the cross-linking agent include 1,10-decanediol diacrylate, pentaerythritol triallyl ether, diethylene glycol diallyl ether, N, N'-methylenebisacrylamide, diethylene glycol diallyl ether, dipropylene glycol diallyl ether, and dibutylene glycol diallyl ether. Examples thereof include dialkylene glycol diallyl ethers such as, polyethylene glycol diallyl ethers, polypropylene glycol diallyl ethers, and polyalkylene glycol diallyl ethers such as polybutylene glycol diallyl ethers.
Among these cross-linking agents, considering that the effect of the present invention can be easily obtained by facilitating the thickening of the ink (developing the ink viscosity) and further facilitating the formation of a stable network structure, 1,10- Decanediol diacrylate, pentaerythritol triallyl ether, diethylene glycol diallyl ether, and N, N'-methylenebisacrylamide are preferable, and more consideration is given, diethylene glycol diallyl ether is preferable.
Therefore, in the present invention, it is preferable to use a crosspolymer containing acrylic acid ester (chemical 1), acrylic acid (chemical 2), and diethylene glycol diallyl ether as constituent components, and specifically, (acrylic acid / acrylic acid). Perfluorohexyl ethyl) crosspolymer is preferred, acrylic acid-4,7,10-trioxatrideca-1,12-diene-3,3,4,4,5,5,6,6,7,7, The 8,8,8-tridecafluorooctyl-acrylic acid copolymer (trade name: Saltrela, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is most preferable.

The ratio (weight ratio) of the cross-linking agent in the copolymer of the present invention is 100 weight in total of acrylic acid ester and acrylic acid in consideration of ink thickening (ink viscosity development) and easy formation of a stable network structure. The amount is preferably 0.0001 to 2 parts by weight, preferably 0.1 to 1.5 parts by weight, more preferably 0.1 to 1 part by weight, still more preferably 0.15 to 0.5 parts by weight. It is a part by weight.

In addition to the above-mentioned acrylic acid ester, acrylic acid, and cross-linking agent, the constituent components of the (acrylic acid / perfluoroalkyl acrylate) copolymer of the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (. A (meth) acrylic acid ester such as a meta) acrylate may be used.

The content of the (acrylic acid / perfluoroalkyl acrylate) copolymer is preferably 0.01 to 10% by mass with respect to the total amount of the ink composition. If it is less than 0.01% by mass, it is difficult to obtain the desired ink thickening, and it is difficult to suppress ink leakage. If it exceeds 10% by mass, the ink viscosity becomes high, so that the writing quality and ink followability are improved. Is likely to be inferior, and more consideration is given, preferably 0.01 to 5% by mass.
Further, in consideration of the above effects, in the case of a water-based ink composition, 0.01 to 5% by mass is preferable, and more consideration is given, 0.1 to 3% by mass is preferable, and 0.5 to 3% by mass is most preferable. 2% by mass. In the case of an oil-based ink composition, it is preferably 0.5 to 5% by mass, more preferably 0.5 to 4% by mass, and most preferably 0.8 to 3.5% by mass.

(solvent)
As the solvent used in the ink composition for writing tools used in the present invention, water, an organic solvent, and a mixed solvent of water and an organic solvent may be used. By using a solvent, the (acrylic acid / perfluoroalkyl acrylate) copolymer can form a stable network structure and a gel structure, so that the ink viscosity can be increased. I guess.

Further, as the water, conventional water such as ion-exchanged water, distilled water and tap water can be used.
Examples of the organic solvent include polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol and glycerin, alkylene glycol alkyl ether solvents such as alkylene glycol monoalkyl ether and alkylene glycol dialkyl ether, and benzyl alcohol. Examples thereof include aromatic alcohols such as, methanol, ethanol, 1-propanol, 2-propanol, isobutanol, and organic solvents such as aliphatic alcohol solvents such as t-butanol.

As the solvent, in the case of an aqueous ink composition, a polyhydric alcohol solvent may be used in consideration of the (acrylic acid / perfluoroalkyl acrylate) copolymer, stability with water, and formation of a stable network structure. Preferably, more preferably, a polyhydric alcohol having a divalent or trivalent hydroxyl group is preferred.
In the case of an oil-based ink composition, an alkylene glycol alkyl ether solvent is preferable, and an alkylene glycol monoalkyl ether is preferable, in consideration of forming a stable network structure with the (acrylic acid / perfluoroalkyl acrylate) copolymer. Further, regarding the carbon number of the alkylene glycol moiety of the alkylene glycol monoalkyl ether, the carbon is considered in consideration of the ease of ink thickening (ink viscosity development) with the (acrylic acid / perfluoroalkyl acrylate) copolymer. The number is preferably 2 to 10, more preferably 3 to 8, and more preferably 5 to 6.
Regarding the carbon number of the alkyl ether moiety of the alkylene glycol monoalkyl ether, consideration is given to the swelling dispersibility with the (acrylic acid / perfluoroalkyl acrylate) copolymer, the writing quality, and the writing property (scratching, suppressing crying). Therefore, it is preferable that the alkyl ether moiety is short. Therefore, the number of carbon atoms is preferably 1 to 6, and is 1 to 4 in consideration of the fact that it is more stable with the (acrylic acid / perfluoroalkyl acrylate) copolymer and the effect is easily obtained. 1-2 is preferable.
Further, an alkylene glycol monoalkyl ether having a solubility parameter (SP value) of 8 to 13 is preferable.

Further, as for the solvent, in the case of the oil-based ink composition, it is preferable that the solvent contains a small amount of water. This is because, for unknown reasons, water has an excellent affinity with the (acrylic acid / perfluoroalkyl acrylate) copolymer and is based on the (acrylic acid / perfluoroalkyl acrylate) copolymer. Higher thickening action and stable swelling property can be imparted to swelling dispersion, and while improving the slipperiness of the writing tip (ball), the ink ejection property is improved, and spot unevenness, crying bottom, scraping, etc. are prevented. This is because it is easy to suppress and improve the writability. In particular, it is preferable to use an alkylene glycol alkyl ether solvent and water in combination as the solvent because it is easy to impart a higher thickening action and stable swelling property.

If the water content is less than 0.1% by mass with respect to the total amount of the ink composition, it tends to affect the slipperiness of the writing tip (ball) and the ink ejection property, and if it exceeds 20% by mass, it is in the ink. Since the solubility tends to be inferior, 0.1 to 20% by mass is preferable with respect to the total amount of the ink composition. Further, 1 to 10% by mass is preferable in consideration of solubility in ink and writeability (suppression of blurring and crying), and 2 to 10% by mass is more preferable in consideration of it.

The content of the solvent in the ink composition for writing tools is preferably 20 to 90% by mass, more preferably 30 to 80% by mass, based on the total amount of the ink composition. When the content of the solvent is within the above numerical range, the (acrylic acid / perfluoroalkyl acrylate) copolymer can form a stable network structure, a gel structure can be formed, and the ink viscosity is increased. It is possible to suppress ink leakage from the gap at the tip of writing, and since the ink viscosity is low at the time of writing, it is possible to suppress writing blurring, excellent writing performance, and easy to improve writing quality.

The compounding ratio of the solvent (solvent / perfluoroalkyl acrylate) to the (acrylic acid / perfluoroalkyl acrylate) copolymer is preferably 10 to 1000 times, preferably 20 times, based on the mass. It is preferably about 200 times, and preferably 30 times to 100 times. This is because, within the above range, a stable network structure is easily formed and a gel structure is easily formed, so that it is easy to obtain an effect of suppressing ink leakage, excellent writing performance, and improving writing quality.

(Colorant)
The colorants used in the water-based ink composition and the oil-based ink composition used in the present invention are not particularly limited, such as dyes and pigments, and can be appropriately selected and used. Dyes and pigments may be used in combination.

As the dye used in the water-based ink composition, a direct dye, an acid dye, a basic dye, a gold-containing dye, various salt-forming type dyes and the like can be adopted.
(A) As direct dyes, Direct Yellow 4, 26, 44, 50, 85, Direct Red 1, 2, 2, 23, 31, 31, 37, 39, 75, 75, and Direct Red 1. 80, 81, 83, 225, 226, 227, Direct Blue 1, 3, 3, 15, 41, 71, 86, 106, 119, Direct Orange 6, etc. (b) As acid dyes, acid black 1, 2, 24, 26, 31, 52, 107, acid orange 56, acid yellow 3, 7, 17, 17, 23, 42, etc. 49, 61, 92, Acid Red 8, 9, 14, 18, 51, 52, 73, 87, 92, 94, Acid Blue 1, 7, 9, 9, 22, Acid 62, 90, 103, Acid Green 3, 9, 16, 25, 27, Acid Violet 15, 17, etc. (c) As the basic dye, C.I. I. Basic Yellow-1, 2, 21, 21, 7, 40, C.I. I. Basic Orange 2, 14, 32, C.I. I. Basic Red 1, 1: 1, 2, 2, 9, 14, C.I. I. Basic Violet 1, 3, 7, 10, 10, 11: 1, C.I. I. Basic Bull-3, 7, 26, Basic Green 4, C.I. I. Basic Brown 12, C.I. I. Basic Black 2, Methyl Violet, Victoria Blue FB, Malachite Green, Rhodamine series, etc. (d) Other dyes include disperse dyes such as Dispers Yellow 82, 121, and Dispers Blue 7.

Dyes used in oil-based ink compositions include oil-soluble dyes, acidic dyes, basic dyes, gold-containing dyes, and various salt-forming type dyes such as salt-forming dyes of acidic dyes and basic dyes. Examples include salt-forming dyes of organic acids and basic dyes, and salt-forming dyes of acidic dyes and organic amines. Considering that the network structure of the (acrylic acid / perfluoroalkyl acrylate) copolymer used in the present invention is not impaired and the ink viscosity is stably increased, it is preferable to use a salt-forming dye.
Dyes include Bali First Black 1802, Bali First Black 1805, Bali First Black 1807, Bali First Violet 1701, Bali First Violet 1704, Bali First Violet 1705, Bali First Blue 1601, Bali First Blue 1605, Bali First Blue 1613, Bali. First Blue 1621, Bali First Blue 1631, Bali First Red 1320, Bali First Red 1355, Bali First Red 1360, Bali First Yellow 1101, Bali First Yellow 1151, Nigrosin Base EXBP, Nigrosin Base EX, BASE OF BASIC DYES ROB-B, BASE OF BASIC DYES RO6GB, BASE OF BASIC DYES VPB-B, BASE OF BASIC DYES VB-B, BASE OF BASIC DYES MVB-3 (manufactured by Orient Chemical Industry Co., Ltd.), Eisenspiron Black GMH-Special , Eisenspiron Violet C-RH, Eisenspiron Blue GNH, Eisenspiron Blue 2BNH, Eisenspiron Blue C-RH, Eisenspiron Red C-GH, Eisenspiron Red C-BH, Eisenspiron Yellow C-GNH, Eisenspiron Yellow C-2GH, S.A. P. T. Blue 111, S.A. P. T. Blue GLSH-Special, S.M. P. T. Red 533, S.M. P. T. Orange 6, S.M. B. N. Yellow 510, S.A. B. N. Yellow 530, S.A. R. C-BH (above, manufactured by Hodogaya Chemical Co., Ltd.) and the like can be mentioned.
Examples of pigments include inorganic, organic, and processed pigments, and specific examples thereof include carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, and diketopyrrolopyrrole. Examples thereof include quinophthalone-based, slene-based, triphenylmethane-based, perinone-based, perylene-based, dioxazine-based, metallic pigments, pearl pigments, fluorescent pigments, phosphorescent pigments and the like.
These dyes and pigments may be used alone or in combination of two or more.

It is preferable to use a pigment as the colorant, because the pigment particles cause a physical obstacle in the gap between the ball and the inner wall of the tip of the tip in the case of a ballpoint pen, and it is easy to suppress ink leakage. Is. Further, the pigment is preferable because it has excellent handwriting fastness and is particularly excellent in light resistance.
Furthermore, by using a pigment, in the case of a ballpoint pen, the pigment particles enter the gap between the ball and the chip body, which makes it easier to act like a bearing, and by suppressing metal contact, the lubricity is improved. It is preferable to use a pigment because it is easy to obtain the effect of improving the writing quality and suppressing the wear of the ball seat. As in the present invention, by using the (acrylic acid / perfluoroalkyl acrylate) copolymer, the ink has a gel structure and the ink viscosity at the time of writing is lowered, so that the metal contact between the ball and the chip body is caused. It is preferable to use a pigment because it is more likely to occur, the lubricity can be improved, and the wear of the ball seat can be suppressed. Further, it is preferable because the lubricity is easily maintained and the writing quality is easily improved by the synergistic effect of the lubricating layer by the surfactant described later and the pigment particles and the bearing action.

The content of the colorant is preferably 1 to 30% by mass with respect to the total amount of the ink composition. This is because if it is less than 1% 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 and dispersibility in the ink. The mass% is preferable, and if further considered, it is 5 to 25 mass%.

(Stabilizer)
In the present invention, it is preferable to use a stabilizer in order to stably swell and disperse the (acrylic acid / perfluoroalkyl acrylate) copolymer in the ink and to easily obtain a stable thickening action. .. Further, even when a surfactant such as a phosphoric acid ester-based surfactant is used, it is preferable to neutralize it because it is easy to obtain the effect of stabilizing the dissolution in the ink and improving the writing taste and the writing performance. Stabilizers include basic inorganic compounds such as ammonia, sodium carbonate, sodium phosphate and sodium hydroxide, alkanolamines such as diethanolamine and triethanolamine, and amines having ethylene oxide such as oxyethylenealkylamine and polyoxyethylenealkylamine. , Alkylamines such as laurylamines and stearylamines, aliphatic amines such as dimethylalkylamines such as distearylamines, dimethyllaurylamines, dimethylstearylamines and dimethyloctylamines, basic organic compounds such as sodium acetate, lactic acid and citrus. Examples include acid.
Among them, a basic inorganic compound is preferable in consideration of the stability with the (acrylic acid / perfluoroalkyl acrylate) copolymer, and an alkanolamine is preferable in consideration of the stability. In particular, in the case of an aqueous ink composition, alkanolamine is preferable, and triethanolamine, which is weakly basic, is preferably used. For oil-based ink compositions, amines with ethylene oxide are preferred. These may be used alone or in admixture of two or more.

The average number of moles of ethylene oxide added (per molecule of amine) (EO number) of the amine having ethylene oxide is preferably 1 to 30, and more preferably 4 to 20. By setting the number of EOs in the above range, the (acrylic acid / perfluoroalkyl acrylate) copolymer is neutralized and stabilized by dissolution stability with a solvent, and a stable thickening action can be easily obtained.

Further, the total amine value of the organic amine is 300 (mgKOH / g) or less in consideration of stability with a solvent, a (acrylic acid / perfluoroalkyl acrylate) copolymer, a colorant and other components. It is preferable to do so. If it exceeds 300 (mgKOH / g), the reactivity is strong and it easily reacts with the above-mentioned components, so that the ink stability with time tends to be inferior. Further, considering the stability with the solvent and the (acrylic acid / perfluoroalkyl acrylate) copolymer, the total amine value is preferably 200 (mgKOH / g) or less, and more preferably 150 (mgKOH / g). g) The following is preferable. On the other hand, in consideration of the above effects, the lower limit of the total amine value is preferably 30 (mgKOH / g) or more.
The total amine value indicates the total amount of primary, secondary and tertiary amines, and is expressed by the number of mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize 1 g of the sample.

Regarding the HLB value of the organic amine, the HLB value is preferably 5 to 17. This is because a stable thickening action can be obtained by neutralizing and stabilizing the (acrylic acid / perfluoroalkyl acrylate) copolymer and stabilizing the swelling and dispersion with the solvent. Further, considering that the neutralization is stabilized and the swelling dispersibility is improved, the HLB value is preferably 7 to 17, and further, further, the HLB value is preferably 9 to 16.

In the present invention, the compounding ratio of the stabilizer (stabilizer / (acrylic acid / perfluoroalkyl acrylate) copolymer) with respect to the (acrylic acid / perfluoroalkyl acrylate) copolymer is 0.1 on a mass basis. It is preferably about 15 times, more preferably 0.3 to 10 times, and more preferably 0.5 to 8 times. This is because the (acrylic acid / perfluoroalkyl acrylate) copolymer is stably swelled and dispersed in the ink, and a stable thickening action can be easily obtained.

The content of the stabilizer is 0. 1 to 10% by mass is preferable, 0.1 to 8% by mass is preferable when neutralization with respect to the phosphoric acid ester-based surfactant is taken into consideration, and 0.5 to 6% by mass is more preferable when more consideration is given.

(Surfactant)
In the present invention, it is easy to improve the writing quality by improving the lubricity, and further, it is considered that the writing performance is improved when the writing tip is dried while the writing tip is left in the atmosphere. , It is preferable to use a surfactant. This is because the lubricating layer formed by the surfactant makes it easier to improve the lubricity, and the surfactant makes it easier to soften the film formed by drying the writing tip and improve the writing performance. This is because it can be done. Examples of the surfactant include fatty acids, silicone-based surfactants, fluorine-based surfactants, phosphate ester-based surfactants, surfactants having an acetylene bond, fatty acid esters, polyalkylene alkyl ethers, alkyl alkanolamides and the like. Can be mentioned. Among them, in consideration of the above effects, it is preferable to use one or more of fatty acids, phosphoric acid ester-based surfactants, and fatty acid esters.
In particular, when used in a ball pen, the phosphoric acid ester-based surfactant has a phosphoric acid group, so that it is easily adsorbed on ball pen chips and balls such as metals, and a lubricating effect is easily obtained. Therefore, the phosphoric acid ester-based surface activity It is preferable to use an agent, and it is preferable because an extreme pressure effect can be easily obtained between the ball and the ball seat, which are metal materials, and the lubricity can be further improved.
In the case of an aqueous ink composition, among the phosphoric acid ester-based surfactants, linear alcohol-based, styrated phenol-based, nonylphenol-based, octylphenol-based and other phosphoric acid ester-based surfactants can be mentioned. It is preferable to use an alcohol-based or styrated phenol-based phosphate ester-based surfactant, and considering that it is easy to improve the writing quality, it is preferable to use a linear alcohol-based phosphate ester-based surfactant. More preferred.
In the case of an oil-based ink composition, among the phosphate ester-based surfactants, a phosphate ester-based surfactant having an acid value of 180 (mgKOH / g) or less is used in consideration of facilitating the improvement of writing quality. It is more preferable to use a phosphate ester-based surfactant having an acid value of 70 to 160 (mgKOH / g), more preferably. The acid value is expressed in mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of the sample.

The HLB value of the surfactant is preferably 5 to 17 in consideration of compatibility with the (acrylic acid / perfluoroalkyl acrylate) copolymer. The HLB value is preferably 6 to 14 in consideration of further improving the swelling dispersibility, lubricity, and writing performance. Further, in consideration of lubricity, the HLB value is preferably 12 or less, and the HLB value is preferably 6 to 12.
The HLB value used in the present invention can be obtained from the Griffin method, the upstream method, or the like. In particular, in haunting writing instruments such as knock-type writing instruments and rotary feeding-type writing instruments, unlike cap-type writing instruments, the writing tip is always exposed to the outside, which affects the writing performance of the writing tip when it dries. It is more preferable to use a surfactant having the above HLB value because it is easy to use.

Specific examples of the surfactant include oleic acid, stearic acid, and linoleic acid as fatty acids, and dimethyl silicone, methylphenyl silicone, polyether-modified silicone, and higher grade silicone-based surfactants. Examples of the fluorine-based surfactant include fatty acid ester-modified silicones, and examples of the fluorine-based surfactant include a perfluoro group-containing butyl sulfonate, a perfluoro group-containing carboxylic acid salt, a perfluoro group-containing phosphoric acid ester, and a perfluoro group-containing phosphoric acid ester type. Examples thereof include formulations, perfluoroalkyl betaines, perfluoroalkylamine oxide compounds, etc. Examples of the phosphate ester-based surfactant include phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers, and polyoxyethylenes. Examples thereof include a phosphoric acid diester of an alkyl ether or a polyoxyethylene alkylaryl ether, a phosphoric acid triester of a polyoxyethylene alkyl ether or a polyoxyethylene alkylaryl ether, an alkyl phosphate ester, an alkyl ether phosphoric acid ester or a derivative thereof.
Among these, it is preferable to use a phosphoric acid ester-based surfactant in consideration of lubricity and thickening action.

The content of the surfactant is more preferably 0.1 to 5.0% by mass with respect to the total amount of the ink composition. This is because if it is less than 0.1% by mass, it is difficult to obtain the desired lubricity, and if it exceeds 5.0% by mass, the ink aging tends to become unstable. It is preferably 0.3 to 3.0% by mass, and more preferably 0.5 to 3.0% by mass with respect to the total amount of the substance.

(resin)
Further, in the present invention, a resin may be used as an ink viscosity adjusting agent, an ink leakage suppressing agent, a pigment dispersant, and a fixing agent. Resins include polyvinyl butyral resin, ketone resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, terpene resin, alkyd resin, phenoxy resin, vinyl acetate resin, polyvinylpyrrolidone resin, ethylene oxide polymer, acrylic resin, styrene-acrylic. Examples thereof include resins, styrene-maleic acid resins, and resin particles such as olefin resin particles, acrylic acid ester resin particles, amino resin particles, acrylic resin particles, and styrene-butadiene resin particles. These may be used alone or in admixture of two or more.

Among these resins, it is preferable to contain resin particles in consideration of suppressing ink leakage, and more preferably, organic resin particles are used, and further, acrylic acid ester resin particles and olefin-based resins. It is preferably contained by selecting from resin particles and amino resin particles. This makes it possible to suppress ink leakage by causing physical damage due to the resin particles from the gap at the tip of the writing (the gap between the ball and the tip of the tip in the case of a ballpoint pen), and further, the particles are one. By forming a structure formed by weak aggregation by partially deforming and sticking to each other, a structure having a high resistance to ink leakage during standing is formed in the ink, which is high. Enables ink leakage suppression. On the other hand, since the structure is formed by weak aggregation, the aggregated structure is crushed by physical action such as rotation of the ball during writing, so that writing is performed well without impairing the ink fluidity during writing. Therefore, it is possible to obtain a good writing taste and a writing property that suppresses blurring.
Further, the effect of suppressing ink leakage due to the stable network structure of the (acrylic acid / perfluoroalkyl acrylate) copolymer and the effect of suppressing ink leakage due to the interaction with the physical damage caused by the resin particles are further enhanced. It is preferable because it is easy to obtain. In particular, it is preferable to use it as an ink composition for a ballpoint pen because it is effective.

The average particle size of the resin particles is preferably 7 μm or less, preferably 5 μm or less, because the smaller the average particle size is, the more the particles are in close contact with each other, it is easy to form a weak aggregated structure, and it is easy to suppress ink leakage. It is preferable, further, considering the dispersion stability of the resin particles in the ink (stability with time of the ink), 3 μm or less is preferable, and further considering, less than 1 μm is more preferable. On the other hand, if the average particle size is too small, the effect of suppressing ink leakage tends to be inferior. Therefore, the average particle size is preferably 0.1 μm or more, more preferably 0.3 μm or more. The average particle size is measured by the Coulter counter method using a Coulter MultisizerTM3 (Measuring device manufactured by Beckman Coulter) based on the numerical value calibrated using a standard sample or another measuring method. It can be obtained by measuring the particle size (D50) when the cumulative volume is 50%.

Among these resin particles, olefin resin particles, acrylic acid ester resin particles, and amino are considered in consideration of the copolymer (acrylic acid / perfluoroalkyl acrylate) in ink, stability to solvent, and suppression of ink leakage. Considering that it is preferable to select from resin particles and use them, and it is easier to stabilize in ink and to improve ink leakage suppression, polyethylene resin particles, methacrylic acid ester resin particles, melamine resin particles, etc. It is preferable to select and use it from the benzoguanamine resin particles, and more preferably, polyethylene resin particles and methacrylic acid ester resin particles are preferable.
In particular, in the case of an aqueous ink composition, olefin resin particles are preferable, and polyethylene resin particles are preferable in consideration of compatibility with a solvent and the effect of suppressing ink leakage, and in the case of an oil-based ink composition, compatibility with a solvent. In consideration of the effect of suppressing ink leakage and ink leakage, acrylic acid ester resin particles are preferable, and methacrylic acid ester resin particles are more preferable.
These resin particles may be used alone or in combination of two or more, and may be a mixture or a copolymer.

As the shape of the resin particles, spherical or irregularly shaped ones can be used, but spherical resin particles are preferable in consideration of the effect of suppressing ink leakage due to the adhesion between the resin particles. The spherical resin particles referred to here are not limited to true spheres, and may be substantially spherical resin particles, substantially elliptical spherical resin particles, or the like.

Further, among the resins, it is preferable to use a ketone resin or a polyvinyl butyral resin in consideration of improving the writing quality, suppressing handwriting blurring and spot unevenness, and facilitating the improvement of pigment dispersibility. It is preferable to use a ketone resin in consideration of handwriting blurring and suppression of spot unevenness (writing property).

Further, the content of the resin particles is more preferably 0.01 to 10% by mass with respect to the total amount of the ink composition. This is because if the content of the resin particles is less than 0.01% by mass, it is difficult to suppress ink leakage, and if it exceeds 10% by mass, the aggregated structure tends to be strong, and the ink stability over time, writing taste, and writing are written. This is because the performance is likely to be affected. Further, more consideration is given, preferably 0.1 to 5% by mass, particularly preferably 0.3 to 3% by mass, and most preferably 0.5 to 3% by mass.

Further, a shear thinning agent other than the (acrylic acid / perfluoroalkyl acrylate) copolymer may be used in combination. The viscosity of the ink composition can be adjusted and the dispersion stability of the pigment can be improved. Specific examples thereof include polysaccharides such as fatty acid amide, hydrogenated castor oil, polyacrylic acid, xanthan gum, welan gum, succinoglycan, guar gum, locust bean gum, λ-carrageenan, cellulose derivative, and daiyutan gum.

Further, in the case of a water-based ink composition, it is preferable to use dextrin in order to suppress ink leakage and improve writing performance. This is because the use of dextrin forms a film when the ink at the tip of the writing is dried. By doing so, the effect of suppressing ink leakage from the gap at the writing tip (in the case of a ballpoint pen, ink leakage from the gap between the ball and the tip of the tip) can be obtained, and further, the writing tip is prevented from drying and solidifying. This is to exert the effect of improving the writing performance by dry-up.

Further, the weight average molecular weight of dextrin is more preferably 5000 to 120,000. When the weight average molecular weight exceeds 120,000, the film formed at the tip of the writing is hard, and the handwriting tends to be blurred during writing during dry-up. On the other hand, when the weight average molecular weight is less than 5,000, the hygroscopicity tends to increase. This is because the film tends to be soft at the tip of the writing, and it is difficult to sufficiently obtain the effect of suppressing ink leakage. Further, when the weight average molecular weight is smaller than 20000, the coating film tends to be thin, so that the weight average molecular weight is most preferably 20000 to 120000.

Other additives include antibacterial agents such as 1,2-benzoisothiazolin-3-one, rust preventives such as benzotriazole, moisturizers such as urea and sorbitol, chelating agents such as ethylenediaminetetraacetic acid, and plasticizers. Can be added. These can be used alone or in combination of two or more.

The ink viscosity of the ink composition for writing tools of the present invention is not particularly limited, but the ink at rest is obtained by imparting shear reducing viscosity with a (acrylic acid / perfluoroalkyl acrylate) copolymer. The viscosity can be increased to facilitate ink leakage suppression, and the ink viscosity during writing can be decreased to facilitate writing quality and writing performance such as blurring.
In the case of the water-based ink composition, the ink viscosity at 20 ° C. and a shear rate of 192 sec ^-1 (at the time of writing) is preferably 300 mPa · s or less because it easily improves the writing taste and the writing property such as blurring, and the writing taste is more preferable. In consideration of writability, 200 mPa · s or less is preferable.
Further, considering ink leakage suppression and ink followability, the ink viscosity at 20 ° C. and a shear rate of 1.92 sec ^-1 (at rest) is preferably 100 to 5000 mPa · s, and more preferably 200 to 3500 mPa · s. s is preferable, and if further considered, 300 to 3000 mPa · s is more preferable. Here, the ink viscosity of the water-based ink composition was measured using a DV-II viscometer (CPE-42 rotor) manufactured by Brookfield.
In the case of an oil-based ink composition, the ink viscosity at 20 ° C. and a shear rate of 20 sec ^-1 (at the time of writing) is preferably 7,000 mPa · s or less, and the ink viscosity is 4000 mPa · s or less in consideration of writing quality and writeability. Preferably, more preferably, the ink viscosity is 3000 mPa · s or less. In addition, the ink viscosity is preferably 100 mPa · s or more, preferably 200 mPa · s or more, and 500 mPa · s or more, considering the writing properties such as handwriting crying, bleeding, strike-through, and handwriting drying property. Is preferable.
Further, considering the ink followability, the ink viscosity at 20 ° C. and a shear rate of 0.18 sec ^-1 (at rest) is preferably 50,000 mPa · s or less, and more preferably 30,000 mPa · s or less. For example, 20000 mPa · s or less is preferable. Further, considering the suppression of ink leakage, the ink viscosity at 20 ° C. and a shear rate of 0.18 sec ^-1 (at rest) is preferably 1000 mPa · s or more, and more preferably 2000 mPa · s or more. For example, 3000 mPa · s or more is preferable.
Here, the ink viscosity of the oil-based ink composition was measured at 20 ° C. using a Viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield.
Further, in a haunting type writing tool such as a knock type writing tool and a rotary feeding type writing tool, it is necessary to further consider the suppression of ink leakage, which is effective.

In the present invention, the viscosity index n refers to n in the viscosity formula represented by S = αD ⁿ . S is the shear stress (dyn / cm ² = 0.1 Pa), D is the shear rate (s ^-1 ), and α is the viscosity coefficient. The viscosity index n can be calculated by measuring the ink viscosity at 20 ° C. using a viscometer as described above.
The viscosity index n is preferably set to a viscosity index n = 0.4 to 0.9 in consideration of writing properties such as ink leakage suppression, writing taste, and blurring, and ink leakage suppression, writing taste, and blurring, etc. Considering the balance of writability, the viscosity index n = 0.5 to 0.85 is preferable, and more considering it, 0.55 to 0.8 is preferable.

(Stationery)
The ink composition for a writing tool of the present invention can be used for a writing tool such as a marking pen or a ballpoint pen having a pen core such as a fiber tip, a felt tip or a plastic tip or a ballpoint pen tip as a pen tip.
The writing tool of the present invention may be configured to directly fill the ink composition for writing tools, or may be provided with an ink container or an ink occlusion body capable of filling the ink composition for writing tools. good.

The haunting mechanism of the writing instrument of the present invention is not particularly limited, and examples thereof include a cap type having a cap covering the pen tip, a knock type, a rotary type, and a slide type. Further, it may be a haunting type that can accommodate the pen tip in the barrel.

Further, the ink supply mechanism in the writing tool is not particularly limited, and for example, (1) a mechanism in which an ink guide core made of a fiber bundle or the like is provided as an ink flow rate adjusting member and the ink composition is supplied to the pen tip. 2) A comb-groove-shaped ink flow rate adjusting member is provided and intervened to supply the ink composition to the pen tip, and (3) an ink flow rate adjusting member by a valve mechanism is provided to supply the ink composition to the pen tip. (4) A mechanism for directly supplying the ink composition to the pen tip from an ink container or a shaft cylinder provided with a pen tip.

In one embodiment, the writing instrument is a marking pen, and the pen tip is not particularly limited, and may be, for example, a fiber tip, a felt tip, a plastic tip, or the like, and the shape thereof may be bullet-shaped, chisel-shaped, or the like. It may be a brush pen type or the like.
In one embodiment, the writing tool is a ballpoint pen, preferably a ballpoint pen provided with an ink backflow preventive body.

(Ballpoint pen tip)
Further, in the case of a ballpoint pen, the amount of movement of the ball of the ballpoint pen tip in the vertical axis direction is preferably 15 to 50 μm in the case of a water-based ballpoint pen. This is because if it is less than 15 μm, it becomes difficult to obtain good writing quality and handwriting blurring suppression, and if it exceeds 50 μm, ink leakage suppression, crying, and ink tracking performance are likely to be affected. For example, it is preferably 20 to 50 μm, and more preferably, the amount of movement in the vertical axis direction is preferably 25 to 45 μm.
In the case of an oil-based ballpoint pen, it is preferably 3 to 25 μm. This is because if it is less than 3 μm, it becomes difficult to obtain good writing quality and handwriting blurring suppression, and if it exceeds 25 μm, ink leakage suppression, crying, and ink tracking performance are likely to be affected. For example, it is preferably 3 to 20 μm, and more preferably, the movement amount in the vertical axis direction is preferably 5 to 16 μm.
The amount of movement (clearance) of the ball of the ballpoint pen tip in the axial direction indicates the distance that the ball can move in the vertical direction of the ballpoint pen tip body.

Further, in order to suppress wear of the ball seat and improve the writing quality, it is preferable to set the arithmetic mean roughness (Ra) of the ball surface to 0.1 to 10 nm. This is because when the arithmetic mean roughness (Ra) exceeds this range, the surface of the ball is too rough and the rotational resistance between the ball and the ball seat tends to increase, which tends to affect the writing quality and wear of the ball seat. Further, if it falls below this range, the ink does not sufficiently adhere to the surface of the ball, so that the writing property such as handwriting blurring tends to be affected. Therefore, in order to suppress wear of the ball seat, improve the writing quality, and obtain sufficient writing performance, the arithmetic mean roughness (Ra) of the ball surface is preferably 0.1 to 10 nm, and is 0. .1 to 8 nm is more preferable, and 0.1 to 6 nm is particularly preferable.
Regarding the arithmetic average roughness of the ball surface, the roughness curve measured by a surface roughness measuring instrument (model name SPI3800N manufactured by Seiko Epson) is extracted by the reference length in the direction of the average line, and the average of the extracted portions is extracted. The absolute value of the deviation from the line to the measurement curve is summed and averaged.

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

The material of the ball pen tip includes metal materials such as stainless steel, nickel silver, brass (brass), aluminum bronze, and aluminum, and resin materials such as polycarbonate, polyacetal, and ABS. Considering the properties and cost, it is preferable to use a stainless steel chip body.

<Example>
Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Example 1>
<Ink composition for water-based ballpoint pens>
A pigment dispersion, water, polyhydric alcohol, stabilizer, organic resin particles, surfactant, and rust preventive are used as colorants, weighed in a predetermined amount, heated to 60 ° C, and then a disper stirrer. The base ink was made by completely dissolving using. Then, while heating the base ink prepared above, a cross polymer (acrylic acid / perfluorohexyl ethyl acrylate) was added, and the mixture was sufficiently mixed and stirred using a homogenizer stirrer until a uniform state was obtained. The ink composition for a water-based ballpoint pen of No. 1 was obtained. The specific blending amount is as follows.
The compounding ratio of the stabilizer to the (acrylic acid / perfluoroalkyl acrylate) copolymer (stabilizer / (perfluoroalkyl acrylate) copolymer) was 1.33 times.
The ink viscosity of Example 1 was measured using a DV-II viscometer (CPE-42 rotor) manufactured by Brookfield Co., Ltd. in an environment of 20 ° C. and a shear rate of 1.92 sec ^-1 (rotation speed 0.5 rpm). When the ink viscosity was measured under the conditions, it was 152 mPa · s at a shear rate of 192 sec ^-1 (rotation speed 50 rpm) in an environment of 1027 mPa · s and 20 ° C. The viscosity index n was 0.59.

Pigment dispersion (colored resin particles, solid content 34%) 20.0% by mass
Water 64.0% by mass
Polyhydric alcohol (glycerin) 10.0% by mass
(Acrylic acid / Perfluorohexyl ethyl acrylate) Cross polymer 1.5% by mass
"Components: Acrylic acid ester (chemical 1), acrylic acid (chemical 2), diethylene glycol diallyl ether (chemical 1) / (chemical 2) = 0.3 Diethylene glycol diallyl with respect to a total of 100 parts by weight of acrylic acid ester and acrylic acid. Acrylic acid ratio: 0.29 parts by weight "
Organic resin particles (polyethylene resin, average particle diameter: 6 μm) 1.0% by mass
Stabilizer (triethanolamine) 2.0% by mass
Phosphoric acid ester-based surfactant (HLB value: 11.5) 1.0% by mass
Rust inhibitor (benzotriazole) 0.5% by mass

<Examples 2 to 9, Comparative Examples 1 to 4>
For water-based ballpoint pens of Examples 2 to 9 and Comparative Examples 1 to 4 in the same manner as in Example 1 except that the types and amounts of the components to be blended were changed with respect to Example 1 as shown in the table. An ink composition was obtained.

The ink composition (1.0 g) for a water-based ballpoint pen produced in Examples 1 to 9 and Comparative Examples 1 to 4 was rotatably held in an ink storage cylinder (polypoly) with a ball having a ball diameter of φ0.7 mm. A ballpoint pen tip (with a coil spring that presses the ball directly against the inner wall of the tip edge of the tip, the amount of movement in the vertical axis direction of the ball: 30 μm, arithmetic average roughness (Ra) of the ball surface: 1 nm) was attached. A ballpoint pen was manufactured by filling it in a ballpoint pen refill. The following tests and evaluations were performed using the writing paper JIS P3201 as the writing test paper.

<Example 11>
<Ink composition for oil-based ballpoint pens>
A colorant, a solvent, a surfactant, and organic resin particles are used, weighed in a predetermined amount, weighed in a predetermined amount, heated to 60 ° C., and then completely dissolved using a disper stirrer. I made a base ink. Then, while heating the base ink prepared above, a cross polymer (acrylic acid / perfluorohexyl ethyl acrylate) was added, and the mixture was sufficiently mixed and stirred using a homogenizer stirrer until a uniform state was obtained. Eleven oiliness was obtained. The specific blending amount is as follows.
The ink viscosity of Example 11 was measured using a viscometer RVDVII + Pro CP-52 spindle manufactured by Brookfield Co., Ltd., and the shear rate was 0.18 sec ^-1 in an environment of 20 ° C. The shear rate was 2700 mPa · s at a shear rate of 20 sec ^-1 under an environment of 15,000 mPa · s and 20 ° C. The viscosity index n was 0.64.

Coloring agent (dye, salt-forming dye of basic dye and acid dye) 10.0% by mass
Colorant (dye, salt-forming dye of basic dye and organic acid) 10.0% by mass
Alkylene glycol monoalkyl ether, carbon number of alkylene glycol moiety: 6, solubility parameter (SP value): 10.5) 74.7% by mass
(Acrylic acid / Perfluorohexyl ethyl acrylate) Cross polymer 3.3% by mass
"Components: Acrylic acid ester (chemical 1), acrylic acid (chemical 2), diethylene glycol diallyl ether (chemical 1) / (chemical 2) = 0.3 Diethylene glycol diallyl with respect to a total of 100 parts by weight of acrylic acid ester and acrylic acid. Acrylic acid ratio: 0.29 parts by weight "
Phosphoric acid ester-based surfactant (HLB value: 8.6) 1.0% by mass
Organic resin particles (methyl methacrylate resin particles, average particle diameter: 0.8 μm 1.0 mass%

<Examples 12 to 27, Comparative Examples 11 to 13>
For oil-based ballpoint pens of Examples 12 to 27 and Comparative Examples 11 to 13 in the same manner as in Example 11 except that the types and amounts of the components to be blended were changed with respect to Example 11 as shown in the table. An ink composition was obtained.

The oil-based ballpoint pen ink compositions (0.27 g) produced in Examples 11 to 27 and Comparative Examples 11 to 13 were rotatably held in an ink storage cylinder (polypropylene) with a ball diameter of φ0.7 mm. A ballpoint pen tip (with a coil spring that presses the ball directly against the inner wall of the tip edge of the tip, the amount of movement in the vertical axis direction of the ball: 8 μm, the arithmetic average roughness (Ra) of the ball surface: 5 nm) was attached. A ballpoint pen was manufactured by filling it in a ballpoint pen refill. The following tests and evaluations were performed using the writing paper JIS P3201 as the writing test paper.

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

(Aqueous ballpoint pen) Ink leakage test: A weight of 40 g is attached to a gel ink ballpoint pen, the ballpoint pen tip is projected downward, and the ball of the ballpoint pen tip is kept in contact with the bottom of the ballpoint pen display case at 20 ° C. The ink was left in an environment of 65% RH for one day, and the amount of ink leaked from the tip of the ballpoint pen tip was measured.
Ink leakage is less than 5 mg ... ◎
Ink leakage amount of 5 to 15 mg ... ○
Ink leakage amount exceeds 15 mg and less than 30 mg ... △
Ink leakage amount of 30 mg or more ・ ・ ・ ×
(Oil-based ballpoint pen) Ink leakage suppression test: The pen tip was left facing downward for 7 days in an environment of 30 ° C. and 85% RH, and ink leakage from the tip tip was confirmed.
No ink droplets on the tip of the chip ・ ・ ・ ◎
Ink droplets on the tip of the chip are within 1/4 of the tapered part ... ○
Ink droplets on the tip of the chip exceed 1/4 of the tapered part and less than 1/2 ... △
Ink droplets on the tip of the chip are more than 1/2 of the taper part ... ×

(Aqueous ballpoint pen) Writing performance test: A running tester with a load of 100 gf and a writing angle of 70 ° and 4 m / min was used to observe the handwriting after the 100 m writing test.
(Oil-based ballpoint pen) Writing performance test: A running tester with a load of 200 gf and a writing angle of 70 ° and 4 m / min was used to observe the handwriting after the 100 m writing test.
Handwriting with no or little blurring ... ◎
There is some cassoulet in the handwriting, but there is no problem in practical use ... ○
There is cassoulet in the handwriting, which has an impact on practical use ... △
Handwriting with a lot of cassoulet ... ×

In Examples 1 to 27, good writing quality, ink leakage suppression test, and writing performance were obtained.
Further, when the pigment inks in Examples 1 to 9 and Examples 23 to 27 were viewed under a microscope, the pigment dispersibility was good and there were no precipitates.
As described above, the ink viscosities of Examples 4 and 12 were measured using a viscometer manufactured by Brookfield Co., Ltd., and the viscosity imparting index n was calculated.
In Example 4, the shear rate was 1.92 sec ^-1 (rotation speed 0.5 rpm) in an environment of 20 ° C., the ink viscosity was 345 mPa · s, and the shear rate was 192 sec ^-1 (rotation speed 50 rpm) in an environment of 20 ° C. The ink viscosity = 73 mPa · s, and the viscosity imparting index n was 0.66.
In Example 12, a shear rate of 0.18 sec ^-1 and an ink viscosity of 10000 mPa · s under an environment of 20 ° C., an ink viscosity of 2000 mPa · s at a shear rate of 20 sec ^-1 and a viscosity imparting index n of 20 ° C. , 0.66.
In Example 23, in an environment of 20 ° C., a shear rate of 0.18 sec ^-1 , ink viscosity = 11000 mPa · s, in an environment of 20 ° C., a shear rate of 20 sec ^-1 , ink viscosity = 2400 mPa · s, and the viscosity imparting index n is , 0.71.
In Example 24, in an environment of 20 ° C., a shear rate of 0.18 sec ^-1 , ink viscosity = 6600 mPa · s, in an environment of 20 ° C., a shear rate of 20 sec ^-1 and an ink viscosity = 2200 mPa · s, the viscosity imparting index n is , 0.79.

In Comparative Examples 1, 2, 11 and 13, since the (acrylic acid / perfluoroalkyl acrylate) copolymer was not used, the ink leakage suppressing performance and the writing performance were inferior.

In Comparative Examples 3, 4 and 12, a shear thinning agent and a resin other than the (acrylic acid / perfluoroalkyl acrylate) copolymer were added, but sufficient ink leakage suppressing effect and writing performance were obtained. There wasn't.

In addition, when using a haunting type writing instrument (a haunting type ballpoint pen) such as a knock type writing instrument or a rotary payout type writing instrument, ink leakage suppression performance is one of the most important performances, so the writing tip portion as in the present invention. The above-mentioned (acrylic acid / perfluoroalkyl acrylate) as in the present invention, which can suppress ink leakage (ink leakage from the gap between the ball and the tip of the tip) from the gaps of the above, and can improve the ink leakage suppression performance. ) It is effective to use an ink composition for writing instruments containing a copolymer.

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

Further, in the present embodiment, for convenience, a ballpoint pen containing a ballpoint pen refill in which the ink composition for a writing tool is directly stored is illustrated, but in the writing tool of the present invention, the shaft cylinder is an ink storage cylinder. A writing tool such as a direct-packing ballpoint pen, a marking pen, or a sign pen in which an ink composition for a writing tool is directly stored in a shaft cylinder may be used. Further, when a marking pen or felt-tip pen in which the ink composition for writing tools is directly stored in the shaft cylinder is used, it can be suitably used because it has an effect of suppressing ink leakage and ink dripping.
Further, in this embodiment, for convenience, a ballpoint pen tip formed by cutting a wire is illustrated, but a ballpoint pen tip formed by pressing a pipe material may be used.

INDUSTRIAL APPLICABILITY The present invention can be used as a writing tool, and more specifically, can be widely used as a ballpoint pen, a marking pen, or a felt-tip pen as a writing tool such as a cap type or a haunting type.

Claims (8)

An ink composition for writing tools, which comprises a colorant, a solvent, and a (acrylic acid / perfluoroalkyl acrylate) copolymer. The writing tool according to claim 1, wherein the content of the (acrylic acid / perfluoroalkyl acrylate) copolymer is 0.1 to 10% by mass with respect to the total amount of the ink composition. Ink composition. The ink composition for writing tools according to claim 1 or 2, wherein the (acrylic acid / perfluoroalkyl acrylate) copolymer contains an acrylic acid ester represented by the general formula (Chemical Formula 1) as a constituent component. thing.

The invention according to any one of claims 1 to 3, wherein the (acrylic acid / perfluoroalkyl acrylate) copolymer contains acrylic acid represented by the general formula (Chemical Formula 2) as a constituent component. Ink composition for writing tools.

The ink composition for writing tools according to any one of claims 1 to 4, wherein the (acrylic acid / perfluoroalkyl acrylate) copolymer contains a cross-linking agent as a constituent component. The ink composition for writing tools according to any one of claims 1 to 5, wherein the ink composition for writing tools contains a surfactant. The ink composition for writing tools according to any one of claims 1 to 6, wherein the ink composition for writing tools contains resin particles. A writing instrument comprising the ink composition for a writing instrument according to any one of claims 1 to 7.