Ink composition for aqueous ballpoint pen, and aqueous ballpoint pen

Abstract

To provide an ink composition for an aqueous ballpoint pen which enables writing of a drawn line that suppresses gloss, is excellent in matte feeling and color development, and has excellent scratch resistance.SOLUTION: An ink composition for an aqueous ballpoint pen contains a coloring material and at least one kind of resin particles selected from the group consisting of an urethane resin, an urea resin, an urea / urethane resin, a melamine resin, an acrylic resin and an olefin resin, wherein a ratio (%) of particles having a particle diameter of 2 μm or more to the total non-water-soluble component in the ink composition is 8% or more based on the volume, and a ratio (%) of particles having a particle diameter of 4 μm or more is 3% or more based on the volume.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an aqueous ink composition for a ballpoint pen which has a matte texture and excellent scratch resistance when drawing lines. [Background technology]

[0002] Ink compositions for writing instruments that prevent bleeding of drawn lines and have abrasion resistance, hiding power, and a smooth writing feel have been developed. As aqueous ink compositions with abrasion resistance and a smooth writing feel, Patent Documents 1 and 2 disclose an aqueous ink composition for writing instruments that contains pigment particles such as titanium oxide, an extender, an aggregation dispersant, an aggregation control agent, a self-crosslinking resin emulsion, polyolefin resin particles, and a solvent and has a viscosity index n of 0.6 to 1.0 at 20°C (Patent Document 1), and an aqueous ink composition for writing instruments that contains pigment particles, an extender, an aggregation dispersant, an aggregation control agent, an acrylic resin, and a solvent and has a viscosity index n of 0.6 to 1.0 at 20°C (Patent Document 2). Also disclosed is an aqueous ink composition for a writing instrument that contains glittering pigment particles, polyolefin resin particles, an elastic polymer, a water-soluble acrylic polymer, and a solvent, the elastic polymer being a styrene-butadiene elastomer or an acrylic elastomer having a glass transition temperature (Tg) of 1 to 70° C., and having a viscosity index n of 0.7 to 1.0 at 20° C. (Patent Document 3). These aqueous ink compositions impart high lubricity and abrasion resistance to written lines by adding relatively large polyolefin resin particles having an average particle size of 0.1 to 35 μm.

[0003] There are also reports of ink compositions with high hiding power and capable of maintaining clear handwriting for a long period of time that contain composite particles of a specified size (Patent Documents 4 and 5). Patent Document 4 discloses an ink composition for writing instruments that contains composite particles with an average particle size of 200 μm or less, in which hiding particles such as titanium oxide and zinc oxide are dispersed in a polymer resin. Patent Document 5 discloses an ink composition for writing instruments that contains microcapsule particles with an average particle size of 200 μm or less, in which a dispersion in which hiding particles and at least one structural viscosity imparting agent selected from silica, linseed oil, and tall oil are dispersed in a solvent is enclosed. In these documents, the ink is provided with a hiding power, a good writing feel, stability, and flowability by blending composite particles or microcapsule particles.

[0004] In addition to the hiding power of drawn lines, there are also reports of suppressing the shine of drawn lines (Patent Document 6). In a water-based ink composition containing 2.5 to 50% by weight of hollow or flat white resin particles with an average particle size of 1.5 μm or less and 2.5 to 50% by weight of a film-forming resin emulsion in terms of solid content, by setting the ratio of the white resin particles to the film-forming resin emulsion to 1:0.2 to 1:3 in terms of solid content, it is possible to form handwriting that is raised, three-dimensional, and has no gloss.

[0005] However, all of these documents relate to ink compositions for felt-tip pens or the like, and aqueous ink compositions for ballpoint pens need to be optimized to achieve abrasion resistance, smooth writing feel, and clear handwriting. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6602199 [Patent Document 2] Patent No. 6509649 [Patent Document 3] Patent No. 6559480 [Patent Document 4] Patent No. 4762509 [Patent Document 5] Patent No. 4756836 [Patent Document 6] JP 2006-70236 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide an aqueous ink composition for a ballpoint pen which has a matte texture, good color development, and excellent abrasion resistance of written lines. [Means for solving the problem]

[0008] The aqueous ballpoint pen ink composition of the present invention contains a colorant and at least one type of resin particle selected from the group consisting of urethane resin, urea resin, urea / urethane resin, melamine resin, acrylic resin, and olefin resin, and the proportion (%) of particles having a particle diameter of 2 μm or more of the total water-insoluble components in the ink composition is 8% or more by volume, and the proportion (%) of particles having a particle diameter of 4 μm or more is 3% or more by volume. At least one of the resin particles is a core-shell type microcapsule, and the thickness of the particle membrane of the microcapsule is preferably 50 to 900 nm, and the particle diameter is preferably 1 to 30 μm. The water-based ballpoint pen of the present invention is equipped with the water-based ballpoint pen ink composition. Effect of the Invention

[0009] According to the present invention, it is possible to provide an aqueous ink composition for a ballpoint pen which has a matte texture with reduced shine, good color development, and excellent abrasion resistance of written lines. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The water-based ballpoint pen ink composition of the present invention will be described in detail below. The aqueous ink composition for ballpoint pens of the present invention (hereinafter also simply referred to as the "ink composition") contains a colorant and at least one type of resin particles selected from the group consisting of urethane resin, urea resin, urea / urethane resin, melamine resin, acrylic resin, and olefin resin.

[0011] As coloring materials for use in the present invention, conventionally known dyes, inorganic and organic pigments, and resin particle pigments can be used. As the dye, various dyes that dissolve or disperse in water can be used. Specific examples include basic dyes such as methyl violet and rhodamine, acid dyes such as acid red 52, eosin (food red No. 103), fuoxin (food red No. 104), brilliant blue FCF, water yellow 6-C, and water blue 105, and direct dyes such as direct sky blue 5B, direct violet BB, and direct black 154.

[0012] The pigment may be any inorganic or organic pigment that is commonly used in aqueous inks for writing instruments, without any particular limitations.Specific examples include inorganic pigments such as carbon black, titanium oxide, zinc oxide, iron oxide, chromium oxide, and ultramarine; and organic pigments such as perylene pigments, perinone pigments, dye lakes, azo lakes, insoluble azo pigments, chelate azo pigments, anthraquinone pigments, phthalocyanine pigments, quinacridone pigments, nitro pigments, and nitroso pigments. The inorganic and organic pigments may be in the form of plastic pigments or resin particles (pseudo pigments) dyed with a basic dye having excellent color development and dispersibility, or may be in the form of hollow resin particles having voids inside the particles as white pigments. Among the above-mentioned coloring materials, carbon black, titanium oxide, organic pigments, or pseudopigments thereof are preferred because they have excellent dispersibility in the aqueous ink composition and are easy to adjust the specific gravity and particle size. As for carbon black, commercially available products such as Mitsubishi Carbon Black #40 (manufactured by Mitsubishi Chemical Corporation) are used. The above-mentioned dyes and pigments are not particularly limited in type, so long as they are those that are commonly used in aqueous inks for writing instruments. In addition, various commercially available products can be used.

[0013] The coloring material usually has an average particle diameter of 70 to 3500 nm in order to impart a matte texture and abrasion resistance to handwriting. Taking into consideration the blending balance with the resin particles, the average particle diameter is preferably 70 to 1500 nm. The content of the colorant in the ink composition of the present invention is usually from 1 to 30% by mass, and preferably from 5 to 20% by mass.

[0014] The resin particles used in the present invention are at least one selected from the group consisting of urethane resin, urea resin, urea / urethane resin, melamine resin, acrylic resin and olefin resin. Urethane resin, urea resin, and urea / urethane resin are resins formed by the reaction of an isocyanate component with an amine component or an alcohol component. Melamine resin is a synthetic resin formed by the polycondensation of melamine and formaldehyde. Acrylic resin is a polymer of (meth)acrylic acid ester. Olefin resin is a resin synthesized using alkenes such as ethylene and propylene as monomers.

[0015] The particle size of the urethane resin, urea resin, urea / urethane resin, melamine resin, acrylic resin, and olefin resin is usually 1 to 30 μm in order to impart a matte texture and abrasion resistance to handwriting, and is preferably 5 to 20 μm in consideration of the blending balance with the coloring material.

[0016] At least one of the at least one resin particles selected from the group consisting of urethane resin, urea resin, urea / urethane resin, melamine resin, acrylic resin, and olefin resin is preferably a core-shell type microcapsule. In addition, the thickness of the particle membrane of the microcapsule is preferably 50 to 900 nm, and the particle diameter is preferably 1 to 30 μm. More preferably, the thickness of the particle membrane is 100 to 700 nm, and the particle diameter is 5 to 20 μm. Core-shell type microcapsules are particles in which a core material such as a water-insoluble solvent or wax is coated with a wall material such as a urethane resin. Microencapsulation can be performed by, for example, interfacial polymerization, interfacial polycondensation, in situ polymerization, liquid hardening coating, phase separation in a fluid system, melt dispersion cooling, air suspension coating, and spray drying, depending on the application.

[0017] The content of the resin particles in the ink composition of the present invention is usually from 1 to 30% by mass, and preferably from 1 to 15% by mass.

[0018] The ink composition of the present invention is usually in a state in which the above-mentioned coloring material and resin particles are dissolved or dispersed in a water-soluble solvent. Examples of the water-soluble solvent include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 3-butylene glycol, thiodiethylene glycol, and glycerin; ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and the like. The content of the water-soluble solvent in the ink composition is usually 3 to 30% by mass.

[0019] The aqueous ballpoint pen ink composition of the present invention contains a colorant and at least one type of resin particle selected from the group consisting of urethane resin, urea resin, urea / urethane resin, melamine resin, acrylic resin, and olefin resin, and the proportion (%) of particles having a particle diameter of 2 μm or more of the total water-insoluble components in the ink composition is 8% or more by volume, and the proportion (%) of particles having a particle diameter of 4 μm or more is 3% or more by volume. Here, in the particle size distribution based on the volume of the entire water-insoluble components of the ink composition of the present invention, the properties of the particles in the ink composition are calculated by a laser diffraction / scattering method utilizing the phenomenon that the scattering angle dependency (scattering pattern) of the scattered light intensity changes depending on the particle size. Note that the "particle size" refers to the particle size calculated on a volume basis with a refractive index of 1.81 using a particle size distribution analyzer Microtrac HRA9320-X100 (manufactured by Nikkiso Co., Ltd.). Furthermore, the proportion (%) of the particles in the entire water-insoluble components of the ink composition is also calculated on a volume basis using the above-mentioned measurement method.

[0020] The term "particles" refers to particles having a particle diameter of 2 μm or more or 4 μm or more in the ink composition, including at least one type of resin particles selected from the group consisting of the urethane resin, urea resin, urea / urethane resin, melamine resin, acrylic resin, and olefin resin. In order to make the ratio (%) of particles having an average particle diameter of 2 μm or more and an average particle diameter of 4 μm or more 8% or more and 3% or more on a volume basis, respectively, commercially available materials with known particle size distributions, such as Chemipearl W401, Chemipearl W800, and Chemipearl W900 (manufactured by Mitsui Chemicals, Inc.), as well as MX-500L and MX-1000 (manufactured by Soken Chemical & Engineering Co., Ltd.), may be added in addition to the resin particles.

[0021] The percentage (%) of particles having a particle diameter of 2 μm or more is preferably 8% or more, more preferably 10% or more, on a volume basis, with the upper limit being approximately 70% or less, preferably 50% or less. The percentage (%) of particles having a particle diameter of 4 μm or more is preferably 3% or more, more preferably 5% or more, on a volume basis, with the upper limit being approximately 25% or less, preferably 20% or less.

[0022] When the ratio (%) of particles having a particle diameter of 2 μm or more and particles having a particle diameter of 4 μm or more is within the above range, the handwriting drawn with the ink composition forms fine unevenness, and a matte feel (matte effect) is obtained. In addition, when the ratio (%) of particles having a particle diameter of 2 μm or more and particles having a particle diameter of 4 μm or more in the entire ink composition is within the above range, the scratch resistance can be improved without impairing the writing feel. When the ratio (%) of particles having a particle diameter of 2 μm or more and particles having a particle diameter of 4 μm or more is less than 8% and less than 3% by volume, respectively, the handwriting drawn with the ink composition does not form a sufficient fine unevenness, and a matte feel (matte effect) cannot be obtained. On the other hand, when the ratio (%) of particles having a particle diameter of 2 μm or more and particles having a particle diameter of 4 μm or more is too large, the ink ejection property is deteriorated, the writing feel is heavy, and the drawn lines may be blurred.

[0023] When the particles are microcapsules, the thickness of the particle membrane is preferably 50 to 900 nm, more preferably 100 to 700 nm. When the particle membrane thickness is in the above range, the particles have an appropriate strength and the ejection property is improved.

[0024] The measurement of the particle membrane of the resin particles in the present invention can be performed by image analysis of a cross-sectional image of the frozen resin particles. Specifically, the dispersed resin particles are freeze-dried using a freeze dryer (RLE-III-103, manufactured by Kyowa Vacuum Engineering Co., Ltd.) to obtain an observation sample, and then the sample is embedded using a two-liquid curing epoxy resin, and a cross section was prepared using a cross-sectional specimen preparation device (cooled cross-section polisher IB-19520CCP, manufactured by JEOL Ltd.). Thereafter, 10 particles having a volume-based particle diameter of 2 μm or more are selected from the obtained cross section using a scanning electron microscope (semi-in-lens FE-SEM S-4700, manufactured by Hitachi High-Tech Corporation), and the selected individual resin particles are observed, and the average value of the particle membranes at five points is calculated. The average particle membrane of the resin particles can be obtained by averaging the selected individual particle membranes.

[0025] The ink composition may contain various additives within the scope of the present invention, such as fragrances, thickeners, pH adjusters, rust inhibitors, lubricants, wetting agents, dispersants, foam inhibitors, defoamers, and preservatives.

[0026] The fragrance imparts a fragrance to the aqueous ballpoint pen, and the components are not limited as long as they are water-insoluble and do not impair the effects of the present invention, such as abrasion resistance, etc. An appropriate amount of the fragrance may be added when the isocyanate component is reacted with the amine component or the alcohol component to produce the urethane resin, urea resin, and urea / urethane resin.

[0027] The thickeners include synthetic polymers, cellulose, and polysaccharides, such as polyvinylpyrrolidone, polyvinyl methyl ether, crosslinked acrylic acid polymers, cellulose and its derivatives, xanthan gum, rheosan gum, welan gum, gellan gum, and succinoglycan.

[0028] Examples of the pH adjuster include ammonia, monoethanolamine, diethanolamine, triethanolamine, urea, sodium tripolyphosphate, sodium carbonate, sodium hydroxide, etc. It is preferable to adjust the pH (25° C.) of the ink composition of the present invention to a range of 6 to 9.5 by appropriately adding a pH adjuster.

[0029] Examples of the rust inhibitor include benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, and saponins. Examples of the lubricant include nonionic surfactants such as fatty acid esters of polyhydric alcohols, higher fatty acid esters of sugars, polyoxyalkylene higher fatty acid esters, and alkyl phosphate esters; anionic surfactants such as phosphate esters, alkyl sulfonates of higher fatty acid amides, and alkyl aryl sulfonates; and lubricants used in the surface treatment of pigments, such as derivatives of polyalkylene glycols and polyether-modified silicones.

[0030] Examples of wetting agents include phosphate esters, fluorine-based surfactants, acetylene-based surfactants, silicone-based surfactants, etc. Wetting agents are used to suppress the repellency of the ink composition on the writing surface.

[0031] As the dispersant, in addition to the water-soluble polymer, the above-mentioned nonionic surfactants and anionic surfactants are used. Foam suppressors include, for example, cysteine, glutathione, hydroxylamine, ascorbic acid, erythorbic acid and their salts, and oligomers of N-vinyl-2-pyrrolidone.

[0032] The defoaming agent may be, for example, a silicone-based emulsion type, an oil type, or an oil compound type, and it is preferable to use a silicone-based emulsion in combination with an oily solvent. Examples of preservatives include sodium benzoate, sodium omadine, thiazoline compounds, and benzimidazole compounds. The above-mentioned additives may be used alone or in combination of two or more.

[0033] The ink composition of the present invention can be prepared by appropriately combining the above-mentioned coloring material, resin particles, water-soluble solvent, and other additives depending on the application of the aqueous ballpoint pen ink, stirring and mixing them with a stirrer such as a homomixer, homogenizer, or disper, and further removing coarse particles in the ink composition by filtration or centrifugation, as necessary.

[0034] In the ink composition of the present invention, the shear rate is 383 sec -1 The viscosity at 25°C is usually 1 to 100 mPa·s, and preferably 30 to 50 mPa·s. If the viscosity at the above shear rate exceeds 100 mPa·s, the ink flow rate is low, making the writing feel heavy and making it difficult to write smoothly. On the other hand, if the viscosity is less than 1 mPa·s, bleeding and bleed-through of handwriting is likely to occur.

[0035] From the viewpoint of writing ability and ink stability, 383sec at 25℃ -1It is preferable that the viscosity is 1 to 100 mPa s and the viscosity index n is 0.1 to 0.8, and it is more preferable that the viscosity is 1 to 80 mPa s and the viscosity index n is 0.2 to 0.75. The viscosity index n is an index representing the pseudoplasticity of a non-Newtonian fluid, and is calculated from the relationship between the shear rate and the apparent viscosity using an Ostwald viscometer.

[0036] By using the ink composition of the present invention, it is possible to write lines with a matte texture and reduced shine, and the lines also have excellent abrasion resistance.

[0037] The water-based ballpoint pen of the present invention is equipped with the ink composition. The ink composition is filled into an ink container (refill) equipped with a ball having a diameter of 0.15 to 2.0 mm, and then an ink follower such as polybutene, silicone oil, or mineral oil is filled into the rear end. The refill is placed in a ballpoint pen barrel equipped with a pen tip such as a ballpoint pen tip, thereby obtaining a water-based ballpoint pen. The structure of the water-based ballpoint pen is not particularly limited, and may be a direct ink type water-based ballpoint pen in which the barrel itself serves as a refill and is filled with an ink composition. EXAMPLES

[0038] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0039] [Preparation of Water-Based Ballpoint Pen Ink Composition] The methods for producing the color materials and resin particles used in Examples 1 to 3 and Comparative Examples 1 to 4 are described below. [Production Example 1: Production of urethane-based colored resin particles A] As an oil phase solution, 11.6 parts of ethylene glycol monobenzyl ether and 1.8 parts of a dispersant (DISPERBYK-111, manufactured by BYK Japan) were heated to 60°C, while 2.0 parts of a pigment (carbon black, CabotMogul L, manufactured by Cabot Corporation) and 0.2 parts of Synergist (phthalocyanine pigment derivative, Solsperse 5000, manufactured by Lubrizol Corporation) were added and thoroughly dispersed. Next, 9.0 parts by mass of a trimethylolpropane adduct of xylylene diisocyanate (Takenate D110N, manufactured by Mitsui Chemicals, Inc.) was added as a prepolymer to prepare an oil phase solution. The aqueous phase solution was prepared by heating 600 parts by mass of distilled water to 60° C. and dissolving 15 parts by mass of polyvinyl alcohol (PVA-205, manufactured by Kuraray Co., Ltd.) as a dispersant therein. The oil phase solution was added to the aqueous phase solution at 60°C, and the mixture was emulsified and mixed by stirring with a homogenizer for 6 hours to complete the polymerization. The resulting dispersion was centrifuged to obtain colored resin particles A. The volume-based average particle diameter of the urethane-based colored resin particles A was 800 nm.

[0040] [Production Example 2: Production of urethane-based colored resin particles B] As an oil phase solution, 11.6 parts of ethylene glycol monobenzyl ether and 1.8 parts of a dispersant (DISPERBYK-111, manufactured by BYK Japan) were heated to 60°C, while 2.0 parts of a pigment (carbon black, CabotMogul L, manufactured by Cabot Corporation) and 0.2 parts of Synergist (phthalocyanine pigment derivative, Solsperse 5000, manufactured by Lubrizol Corporation) were added and thoroughly dispersed. Next, 9.0 parts by mass of a trimethylolpropane adduct of xylylene diisocyanate (Takenate D110N, manufactured by Mitsui Chemicals, Inc.) was added as a prepolymer to prepare an oil phase solution. The aqueous phase solution was prepared by heating 600 parts by mass of distilled water to 60° C. and dissolving 10 parts by mass of polyvinyl alcohol (PVA-205, manufactured by Kuraray Co., Ltd.) as a dispersant therein. The oil phase solution was added to the aqueous phase solution at 60°C, and the mixture was emulsified and mixed by stirring with a homogenizer for 6 hours to complete the polymerization. The resulting dispersion was centrifuged to obtain colored resin particles B. The median diameter of the urethane-based colored resin particles B was 2.0 μm on a volume basis.

[0041] [Production Example 3: Production of urethane resin particles C] Except for not adding the pigment and synergist, urethane resin particles C were produced in the same manner as in Production Example 2. The volume-based median diameter of the urethane resin particles C was 5.5 μm.

[0042] [Production Example 4: Production of melamine-based resin particles E] Styrene-maleic anhydride copolymer (A-C573A, 573P, Honeywell) was dissolved with a small amount of sodium hydroxide to prepare a 5% aqueous solution with a pH of 4.5. To this solution, 200 parts by weight of lemon flavor (PH-6968, Takasago International Corporation) was added, and the mixture was emulsified using an ultra-homogenizer manufactured by Nippon Seiki Co., Ltd. On the other hand, 20 parts by weight of melamine and 45 parts by weight of 37% by weight formalin were added to 35 parts by weight of water, and the pH was adjusted to 9.0 with a 20% by weight aqueous sodium hydroxide solution, followed by heating at 80° C. for 30 minutes to prepare an aqueous methylolmelamine solution. Next, this methylolmelamine aqueous solution was added to the above emulsion and mixed at 75°C for 2 hours to obtain a microcapsule dispersion having a melamine resin wall membrane encapsulating lemon fragrance. The particle size of this microcapsule was measured using a Microtrac HRA9320-X100 (manufactured by Nikkiso Co., Ltd.), and the median diameter in the volumetric particle size distribution was 6.0 μm, and the proportion of particles 2 μm or larger was 90%.

[0043] The methods for preparing the ink compositions of Examples 1 to 3 and Comparative Examples 1 to 4 are described below. [Example 1] An ink composition was prepared by mixing 0.1 mass% of carbon black (Mitsubishi Chemical Corporation, Mitsubishi Carbon Black #40 (average particle size 400 nm)), 15.0 mass% of colored resin particles A prepared in Production Example 1 (average particle size 800 nm), 2.0 mass% of acrylic particles (Soken Chemical & Engineering Co., Ltd., MX-1000 (average particle size 10.0 μm)), 0.3 mass% of xanthan gum, 3.0 mass% of ethylene glycol, 8.0 mass% of glycerin, 8.0 mass% of additives, and 63.6 mass% of distilled water (referred to as the balance in Table 1).

[0044] [Examples 2-3] [Comparative Examples 1-4] The coloring material, resin particles, thickener, water-soluble solvent and other additives were mixed in the proportions shown in Table 1 to prepare an ink composition. In Table 1, "balance" is the value obtained by subtracting the total amount (mass %) of each component from 100 mass % of the glittering water-based ink. The resin particles used in Example 3 and Comparative Example 1, which are polyolefin particles F (average particle size 600 nm) in Table 1, are Chemipearl W900 manufactured by Mitsui Chemicals.

[0045] [Preparation of water-based ballpoint pen] Using the barrel of a ballpoint pen (manufactured by Mitsubishi Pencil Co., Ltd., product name: Uni-ball Signo UMN-307), each water-based ballpoint pen ink composition was filled into a refill consisting of a polypropylene ink reservoir tube with an inner diameter of 3.8 mm and a length of 113 mm, a ballpoint pen tip (holder: stainless steel, ball: carbide ball, ball diameter: 0.5 mm), and a joint connecting the reservoir tube and the tip. Five water-based ballpoint pens were prepared by filling the refill with each water-based ballpoint pen ink composition and filling the rear end of the ink with an ink follower made of polybutene.

[0046] 〔evaluation〕 (1) Matte finish The gloss of the drawn lines was visually confirmed and the evaluation criteria were as follows: A: It had a matte finish. B: Slightly glossy C: It had a glossy feel.

[0047] (2) Scratch resistance After preparation, each aqueous ballpoint pen ink composition was filled into a ballpoint pen after 24 hours had passed, and a spiral was handwritten on writing paper. After 24 hours, a Kimwipe (manufactured by Nippon Paper Crecia Co., Ltd.) wrapped around a weight of 200 g was placed on the drawn line, and the Kimwipe was moved 10 cm in the central axis direction of the spiral 50 times in the same direction. After that, the peeling of the drawn line was visually confirmed. The evaluation criteria are as follows. A: No peeling and clear writing B: Some peeling and slightly unclear writing C: Significant peeling and unclear handwriting

[0048] [Table 1]

[0049] Comparative Example 1, in which the ratio of particles having a particle diameter of 4 μm or more was as low as 2%, had abrasion resistance, but the handwriting was shiny and had a poor matte feel. In Comparative Examples 2 to 4, in which particles having a particle diameter of 4 μm or more were not included, the handwriting was stained when lightly rubbed, and all of them had poor abrasion resistance. From the results of Comparative Examples 2 to 4, it was found that when particles having a particle diameter of 4 μm or more were not included, a matte feel or abrasion resistance could not be obtained even if the content of particles having a particle diameter of 2 μm or more was changed within the range of 5 to 65%.

Claims

1. The ink contains a coloring material and at least one type of resin particles selected from the group consisting of a urethane resin, a urea resin, a urea / urethane resin, a melamine resin, an acrylic resin, and an olefin resin, An aqueous ballpoint pen ink composition, characterized in that the percentage (%) of particles having a particle diameter of 2 μm or more in the total water-insoluble components in the ink composition is 8% or more by volume, and the percentage (%) of particles having a particle diameter of 4 μm or more is 3% or more by volume.

2. 2. The aqueous ballpoint pen ink composition according to claim 1, wherein at least one of the resin particles is a core-shell type microcapsule, the thickness of the particle membrane of the microcapsule is 50 to 900 nm, and the particle diameter is 1 to 30 μm.

3. An aqueous ballpoint pen equipped with the aqueous ballpoint pen ink composition according to claim 1 or 2.

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