Writing instrument set and method for using the same

Abstract

To provide a writing instrument set and a method for using the same, which allow a user to easily write a writing line with gradation formed thereon in a short time and also prevents deterioration of the feeling of use of a marker pen.SOLUTION: Provided is a writing instrument set including a marker pen that accommodates a first water-based ink and ejects it through the pen tip, and an ink container having an ink bottle that accommodates a second water-based ink. The first water-based ink contains a first coloring material, the second water-based ink contains a second coloring material, the first coloring material and the second coloring material are composed of acid dyes, basic dyes, pigments or colored particles, and when the second coloring material is colored particles, the first coloring material is composed of acid dyes, basic dyes or pigments.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a writing instrument set and a method for using the same. [Background technology]

[0002] In recent years, it has become common to impregnate the tip of a marker pen of one color with ink of another color to form letters or patterns with gradation. As a method for impregnating the tip of a marker pen of one color with ink of another color, a method of bringing the marker pen tips into contact with each other is known (see Patent Document 1 below). This method requires the use of gravity (holding the marker pen vertically) to transfer the ink from one marker pen to the other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4833223 Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the method described in the above Patent Document 1, it takes time to impregnate the tip of the marker pen with the other color ink and requires the use of a special tool, making it impossible to easily write lines with gradation in a short amount of time. In addition, depending on the combination of the ink used in the marker pen and the ink impregnated in the nib of the marker pen, problems such as deposits or aggregates on the nib or the written lines, or color remaining on the nib may occur. As a result, the usability of the marker pen may decrease, and the desire to continue writing lines with gradations using the marker pen may become difficult. Therefore, there has been a demand for a method that allows writing lines with gradation to be written easily in a short amount of time and prevents deterioration in the usability of the marker pen.

[0005] The present invention aims to provide a writing instrument set and a method for using the same, which allows a user to easily write lines with gradation in a short time and also prevents deterioration in the usability of a marker pen. [Means for solving the problem]

[0006] As a result of intensive research by the present inventors to solve the above problems, the above problems have been solved by the following invention.

[0007] That is, the present invention provides "(1) a writing instrument set comprising a marker pen that contains a first water-based ink and ejects it through the pen tip, and an ink container having an ink bottle that contains a second water-based ink, wherein the first water-based ink contains a first coloring material, the second water-based ink contains a second coloring material, the first coloring material and the second coloring material are composed of acid dyes, basic dyes, pigments or colored particles, and when the second coloring material is colored particles, the first coloring material is composed of acid dyes, basic dyes or pigments." According to the writing set described in (1) above, when the nib of the marker pen is dipped in the second water-based ink contained in the ink bottle of the ink container and writing is performed on the surface of the writing object such as paper, the color of the second water-based ink gradually fades in the written line, and eventually the color of the first water-based ink appears, making it possible to easily write a written line with a gradation in a short time. In addition, even when using the marker pen, the occurrence of precipitates or aggregates on the nib or written line is suppressed, making it difficult for color to remain on the nib. In this way, it is possible to write lines with a gradation formed thereon, and deterioration in the feel of the marker pen when used can be suppressed. Even when the second coloring material is a colored particle, the above effect can be obtained by forming the first coloring material from an acid dye, a basic dye, or a pigment. The details of the reason are unclear, but it is thought to be as follows. That is, fine aggregates may be generated in the second water-based ink contained in the ink bottle, and even in this case, the aggregates tend to settle to the bottom of the ink bottle. For this reason, even when a marker pen is used by immersing it in the second water-based ink in the ink bottle, the aggregates are unlikely to adhere to the pen tip of the marker pen, and as a result, it is thought that the aggregates are unlikely to be observed on the writing line.

[0008] The present invention may also be "(2) a writing instrument set as described in (1) above, in which the first colorant and the second colorant contain the pigment, the first water-based ink contains a first dispersant, the second water-based ink contains a second dispersant, and the first dispersant and the second dispersant are composed of surfactants having the same hydrophilic group or hydrophilic structure, or resins polymerized using the same monomer." According to the writing instrument set described in (2) above, when the nib of the marker pen is immersed in the second water-based ink contained in the ink bottle of the ink container and then writing on paper, the occurrence of precipitates or aggregates on the nib or on the writing line is further suppressed.

[0009] The present invention may also be "(3) a writing instrument set according to (1) or (2) in which the tip of the marker pen is composed of a fiber tip, a porous tip, or a plastic tip." The present invention may be "(4) the writing instrument set according to (1) or (2)", in which the first water-based ink and the second water-based ink have a viscosity of 3.0 to 11.0 mPa·s." According to the writing instrument set described in (4) above, when the tip of the marker pen is immersed in the second water-based ink contained in the ink bottle of the ink container and used to write on the surface of a writing object such as paper, the ink is less likely to bleed or show through, and the writing lines are less likely to fade, compared to when the viscosity is outside the above range.

[0010] The present invention may be "(5) the writing instrument set according to any one of (1) to (4) above, in which the difference in viscosity between the first water-based ink and the second water-based ink is 8.0 mPa·s or less." According to the writing instrument set described in (5) above, when the tip of the marker pen is immersed in the second water-based ink contained in the ink bottle of the ink container and used to write on the surface of a writing object such as paper, the ink is less likely to bleed or show through, and the writing lines are less likely to fade, compared to when the viscosity difference is outside the above range.

[0011] The present invention may also be a writing instrument set described in any one of (1) to (4), wherein (6) the ink bottle comprises a main body and a cylindrical mouth connected to the main body, and wherein, when the height from the bottom surface of the main body to the tip surface of the mouth is h (cm), the inner diameter of the mouth is y (cm), and the maximum outer diameter of the marker pen from the tip of the marker pen to height h is x (cm), the ratio R(y / x) of y to x is 1.5 or greater. According to the writing instrument set described in (6) above, when the tip of the marker pen is inserted into the ink bottle and immersed in the second water-based ink, the liquid level of the second water-based ink is easily visible and the marker pen can be easily tilted in the ink bottle relative to the extension direction of the main body, making it possible to check the degree of adhesion of the second water-based ink to the tip while visually checking the tip.

[0012] The present invention provides "(7) a method of using a writing instrument set using a writing instrument set described in any one of (1) to (6), comprising a step of immersing the tip of the marker pen of the writing instrument set in the second water-based ink contained in the ink bottle of the ink container, and writing on the surface of an object to be written on." According to the method of using the writing set described in (7) above, in one step, the tip of the marker pen of the writing set is immersed in the second water-based ink contained in the ink bottle of the ink container, and writing is performed on the surface of the writing object such as paper, so that the color of the second water-based ink gradually fades in the written line, and eventually the color of the first water-based ink appears, and a written line with a gradation can be written easily in a short time. Also, even when the marker pen is used, the occurrence of precipitates or aggregates on the pen tip or the written line is suppressed, and color is less likely to remain on the pen tip. In this way, it is possible to write lines with a gradation formed thereon, and deterioration in the feel of the marker pen when used can be suppressed. Effect of the Invention

[0013] According to the present invention, it is possible to provide a writing instrument set and a method for using the same that enable a user to easily write lines with a gradation in a short amount of time and also suppress deterioration in the usability of the marker pen. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing one embodiment of a writing instrument set according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of a writing instrument set of the present invention will be described in detail with reference to FIG.

[0016] As shown in Fig. 1, the writing instrument set 100 includes a marker pen 10 and an ink container 20. Although the writing instrument set 100 in Fig. 1 includes only one ink container 20, the writing instrument set 100 may include a plurality of ink containers 20 each containing water-based ink. The water-based inks contained in the plurality of ink containers 20 may be inks of different colors or inks of the same color.

[0017] The marker pen 10 comprises a cylindrical shaft 3, a cylindrical central axis 6 connected to the end of the shaft 3, a spool 4 housed in an ink storage section 1 formed by a gap inside the shaft 3 and a gap inside the central axis 6, and a pen tip 2 fixed in the central axis 6 and inserted into the spool 4. The shaft 3, the central axis 6, the ink storage section 1, the spool 4, and the pen tip 2 extend along an axis A1. The spool 4 contains a first water-based ink 5 containing a first coloring material. Therefore, the first water-based ink 5 contained in the spool 4 can be ejected through the pen tip 2. The marker pen 10 may further include a cap (not shown) provided to cover the pen tip 2. 1 has a pen tip 2 at one end, it may have pen tips 2 at both ends. Furthermore, the marker pen 10 in FIG. 1 is a padded type, but the marker pen of this embodiment may be a direct ink type. That is, the first water-based ink 5 may be directly contained in the ink container 1.

[0018] 1, the ink container 20 includes an ink bottle 21 and a second water-based ink 22 contained in the ink bottle 21. The second water-based ink 22 contains a second coloring material. The ink bottle 21 has a cylindrical main body 21a having a bottom surface, and a cylindrical mouth 21b connected to the main body 21a via a connecting portion 21c. In this embodiment, the inner diameter of the mouth 21b is smaller than the inner diameter of the main body 21a. The ink container 20 may further include a cap (not shown) that is attached to the mouth portion 21b. The mouth portion 21b may be directly connected to the main body portion 21a without the connection portion 21c.

[0019] In the writing instrument set 100, the first coloring material contained in the first water-based ink 5 and the second coloring material contained in the second water-based ink 22 are composed of an acid dye, a basic dye, a pigment, or colored particles. That is, when the first coloring material is composed of an acid dye, the second coloring material is composed of an acid dye, when the first coloring material is composed of a basic dye, the second coloring material is composed of a basic dye, when the first coloring material is composed of a pigment, the second coloring material is composed of a pigment, and when the first coloring material is composed of colored particles, the second coloring material is composed of colored particles. When the second coloring material is composed of colored particles, the first coloring material may be composed of an acid dye, a basic dye, or a pigment.

[0020] Next, how to use the writing instrument set 100 will be described. First, the pen tip 2 of the marker pen 10 of the writing set 100 is dipped into the second water-based ink 22 contained in the ink bottle 21 of the ink container 20, and writing is performed on the surface of a writing target such as a piece of paper. Then, in the written line, the color of the second water-based ink 22 gradually fades and eventually the color of the first water-based ink 5 appears, making it possible to easily write a written line with a gradation in a short time. Also, even when using the marker pen 10, the occurrence of precipitates or aggregates on the pen tip 2 or the written line is suppressed, making it difficult for color to remain on the pen tip 2. In this way, it is possible to write lines with gradation and to suppress deterioration in the usability of the marker pen 10. As a result, the desire to use the marker pen 10 to write lines with gradation is maintained. Thereafter, if necessary, the pen tip 2 of the marker pen 10 may be dipped into a second water-based ink 22 contained in an ink bottle 21 of the same ink container 20, and further writing may be performed on the surface of the writing target, such as a piece of paper. In addition, when the writing instrument set 100 has multiple ink containers 20, the nib 2 of the marker pen 10 may be dipped into the second water-based ink 22 contained in the ink bottle 21 of the ink container 20 and used to write on the surface of the writing object, such as paper, and then the nib 2 of the marker pen 10 may be dipped into the second water-based ink 22 contained in the ink bottle 21 of a different ink container 20 and used to write on the surface of the writing object, such as paper.

[0021] The marker pen 10 and the ink container 20 will be described in detail below. (1) Marker pen (Shaft body and center shaft) The shaft 3 and the center shaft 6 may be made of a plastic material such as polypropylene.

[0022] (Pen tip) The pen tip 2 is not particularly limited as long as it is capable of ejecting the first water-based ink 5, and the pen tip 2 may be a fiber tip, a felt tip, a porous tip, a plastic tip, or the like. The fiber tip is a tip formed by binding a fiber bundle with a resin. The porous tip is a porous tip formed by fusing resin particles such as polypropylene. The plastic tip is a resin tip having one pore. Among them, the fiber tip or the porous tip is preferable. The shape of the pen tip 2 may be bullet-shaped, chisel-shaped, brush-pen-shaped, etc. The cross-sectional shape of the pen tip 2 is not particularly limited and may be a square, polygonal, round bar-like, etc. The pen tip 2 contains, for example, a resin. Examples of the resin include polyacetal, polyamide, polybutylene terephthalate, polyethylene terephthalate, acrylic resin, polyvinylidene fluoride, polyether ether ketone, polyether sulfone, polyurethane, etc. These can be used alone or in combination of two or more kinds. The pen tip 2 may further contain fillers and additives, such as organic particles having hydrogen-bonding functional groups, inorganic particles, and electrostatic agents. The pen tip 2 may be one in which a coating material such as a surface modifier is applied to the surface of the pen tip body to increase the adhesive force with the first color material by hydrogen bonding, electrostatic attraction, or the like. The pen core contains voids made of pores, the pore size of which can be set arbitrarily as long as it is large enough for the coloring material to pass through, and the porosity is preferably 55 to 75%, more preferably 60 to 70%, in the case of a fiber tip, and preferably 30 to 50%, more preferably 40 to 50%, in the case of a porous tip. If the porosity of the pen core is within the above range, clogging of the first coloring material is unlikely to occur, and an appropriate amount of ink can be discharged.

[0023] (First water-based ink) The first water-based ink 5 contains a first coloring material and water. The first water-based ink 5 may further contain at least one of a water-soluble organic solvent, a pH adjuster, a viscosity adjuster, a preservative, and a first dispersant, as necessary.

[0024] (First coloring material) The first color material includes an acid dye, a basic dye, a pigment, and colored particles.

[0025] Acid dyes and basic dyes are water-soluble dyes. Examples of the acid dye include CIAcid Black 2, 31, CIAcid Yellow 3, 17, 23, 73, CIAcid Orange 10, CIAcid Red 13, 14, 18, 27, 52, 73, 87, 92, CIAcid Blue 1, 9, 74, 90, Water Green 8, and CIAcid Violet-based acid dyes such as CIAcid Violet 48. The above acid dyes may be used alone or in combination of two or more.

[0026] Examples of basic dyes include CI Basic Yellow 2, 3, 28, 40, CI Basic Red 1, 2, 8, 12, CI Basic Violet 1, 3, 10, CI Basic Blue 3, 5, 9, 26, etc. The basic dyes may be used alone or in combination of two or more kinds.

[0027] The pigment is preferably a water-dispersible pigment. The water-dispersible pigment is not particularly limited as long as it can be dispersed in an aqueous medium, and examples of the water-dispersible pigment include inorganic pigments and organic pigments. These may be used alone or in combination of two or more. Examples of inorganic pigments include carbon black and metal powders, which may be used alone or in combination of two or more. Examples of organic pigments include blue pigments such as CI Pigment Blue 2, 3, 9, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17, 28, 29, 36, 60, 68, and 76; red pigments such as CI Pigment Red 5, 8, 9, 17, 31, 48:1, 48:2, 48:3, 48:4, 53:1, 57:1, 122, 144, 146, 166, 170, 177, 202, 207, 211, 213, 254, 255, 264, 270, and 272; and red pigments such as CI Pigment Yellow Yellow pigments such as CI Pigment Green 7, 36, 37, and orange pigments such as CI Pigment Orange 13 can be used. These may be used alone or in combination of two or more.

[0028] The colored particles are resin particles colored with a colorant. The colorant may be, for example, a dye or a pigment. The dye may be the above-mentioned acid dye or basic dye, but the basic dye is usually used. Examples of the resin particles include acrylic resin particles and acrylonitrile butadiene resin particles.

[0029] When the second coloring material is composed of colored particles, the first coloring material is preferably composed of an acid dye, a basic dye, or colored particles. In this case, when the pen tip 2 of the marker pen 10 is immersed in the second water-based ink 22 contained in the ink bottle 21 of the ink container 20, the first water-based ink 5 is less likely to be mixed into the second water-based ink 22.

[0030] When the first coloring material is an acid dye or a basic dye, the content of the first coloring material is preferably 0.1 to 10.0 mass %, and more preferably 0.1 to 3.0 mass %, based on the total amount of the first water-based ink 5. When the first coloring material is a pigment, the content of the first coloring material is preferably 3.0 to 15.0 mass %, and more preferably 5.0 to 10.0 mass %, based on the total amount of the first water-based ink 5.

[0031] (water) The water content is preferably 10.0 to 80.0 mass %, and more preferably 50.0 to 80.0 mass %, based on the total amount of the first water-based ink 5.

[0032] (Water-soluble organic solvent) Examples of the water-soluble organic solvent include glycerin, propylene glycol, ethylene glycol, diethylene glycol, etc. When the first water-based ink 5 contains the water-soluble organic solvent, the first water-based ink 5 tends to have a moisturizing effect. The content of the water-soluble organic solvent is preferably 5.0 to 50.0 mass %, and more preferably 10.0 to 30.0 mass %, based on the total amount of the first water-based ink 5.

[0033] (pH adjuster) Examples of pH adjusters that can be used include inorganic salts such as sodium carbonate, sodium phosphate, sodium hydroxide, and sodium acetate, and organic basic compounds such as water-soluble amine compounds such as triethanolamine and diethanolamine. The content of the pH adjuster is preferably 0.1 to 5.0% by mass based on the total amount of the first water-based ink 5.

[0034] (Viscosity modifier) Examples of viscosity adjusters include natural thickeners such as xanthan gum, guar gum, locust bean gum, carrageenan, gum arabic, tragacanth gum, alginic acid, gelatin, agar, casein, psyllium seed gum, and tamarind seed gum, as well as synthetic thickeners such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, sodium alginate, polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, sodium polyacrylate and carboxyvinyl polymer, and polyethylene glycol. The content of the viscosity modifier is preferably 0.1 to 20.0% by mass, and more preferably 0.1 to 10.0% by mass, based on the total amount of the first aqueous ink 5. When the content of the viscosity modifier is 20.0% by mass or less, an excessive increase in the viscosity of the first aqueous ink 5 is suppressed, and clogging of the first aqueous ink 5 at the pen tip 2 tends to be suppressed. On the other hand, when the content of the viscosity modifier is 0.1% by mass or more, an excessive decrease in the viscosity of the first aqueous ink 5 is suppressed, and ink leakage from the pen tip 2 tends to be suppressed.

[0035] (Preservatives) Preservatives include carbolic acid, the sodium salt of 1,2-benzisothiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, thiolpyridine oxide salts, and 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine. The content of the preservative is preferably 0.1 to 5 mass %, and more preferably 0.1 to 1 mass %, based on the total amount of the first water-based ink 5.

[0036] (First dispersant) When the first coloring material contains a pigment, it is preferable that the first water-based ink 5 contains a first dispersant in order to improve the dispersibility of the pigment. The first dispersant is composed of a surfactant having a hydrophilic group or a hydrophilic structure, a resin, and a self-dispersing pigment in which the pigment surface has been subjected to a hydrophilization treatment. The hydrophilic group includes a carboxy group, a sulfo group, a hydroxy group, a phosphate group, an amino group, and salts thereof. Examples of the hydrophilic structure include ethylene oxide and propylene oxide. Examples of surfactants having a hydrophilic group or hydrophilic structure as described above include polycarboxylic acid type polymer surfactants, alkyl sulfuric acids; higher fatty acids such as alkylbenzenesulfonic acids and oleic acid; thiophosphite triesters such as thiophosphite tri(alkoxycarbonylmethyl ester) and thiophosphite tri(alkoxycarbonylethyl ester); alkyl ether sulfates, their metal salts, ammonium salts, amine salts, and alkanolamine salts; polyoxyethylene alkyl ethers; polyoxyethylene alkyl ether phosphates; alkyl trimethylammonium; and alkyl carboxybetaines. The content of the surfactant is preferably 0.3 to 5 mass %, and more preferably 0.5 to 3 mass %, based on the total amount of the first water-based ink 5.

[0037] A resin is a polymer formed by polymerization using a monomer. The monomers include acrylic acid, maleic acid, maleic anhydride, styrene, styrenesulfonic acid, naphthalenesulfonic acid, acrylamide, ethyleneimine, alginic acid, and vinylimidazoline. Examples of the resin include carboxyl group-containing resins, modified carboxyl group-containing resins, salts of modified carboxyl group-containing resins, polyacrylamide resins, and naphthalenesulfonate-formaldehyde combinations. Examples of carboxyl group-containing resins include acrylic resins, styrene-maleic acid resins, olefin-maleic anhydride copolymers, and polystyrene sulfonic acid resins. The resin content is preferably 5.0 to 30.0% by mass, and more preferably 10.0 to 20.0% by mass, based on the total amount of the first water-based ink 5.

[0038] When the second coloring material is colored particles, the first dispersant is preferably a resin rather than a surfactant. In this case, when the pen tip 2 of the marker pen 10 is immersed in the second water-based ink 22 contained in the ink bottle 21 of the ink container 20, the first water-based ink 5 is less likely to be mixed into the second water-based ink 22.

[0039] The viscosity of the first water-based ink 5 is preferably 3.0 to 11.0 mPa·s, and more preferably 3.0 to 6.0 mPa·s. When the viscosity is 3.0 mPa·s or more, when the pen tip 2 of the marker pen 10 is dipped in the second water-based ink 22 contained in the ink bottle 21 of the ink container 20 and writing on paper, the ink is less likely to bleed or show through, and the written lines are less likely to be smudged. When the viscosity is 11.0 mPa·s or less, when the pen tip 2 of the marker pen 10 is dipped in the second water-based ink 22 contained in the ink bottle 21 of the ink container 20 and writing on paper, the written lines are less likely to be smudged. The viscosity was measured at a temperature of 25°C and a shear rate of 225 s -1 This refers to the viscosity at

[0040] The first water-based ink 5 can be obtained by mixing the above-mentioned components using a stirrer such as a dissolver, a Henschel mixer, a homomixer, etc. The stirring conditions of the stirrer are not particularly limited, but for example, the first water-based ink 5 in which each component is uniformly dispersed can be obtained by stirring for 30 to 180 minutes at a rotation speed of 100 to 1000 rpm using a dissolver stirrer.

[0041] (2) Ink container (Ink bottle) The ink bottle 21 is made of, for example, glass or resin. The ink bottle 21 may be either transparent or opaque, but is preferably transparent.

[0042] (cap) The cap has a cap body. For example, it is made of a resin. Examples of the resin include polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and polyacetal resin (POM). These can be used alone or in combination of two or more kinds. The cap body includes, for example, a cylindrical portion and a lid portion that closes one end opening of the cylindrical portion. The cap may further include a sheet for preventing ink leakage inside the cylindrical portion of the cap body. The sheet is not particularly limited as long as it is made of a water-resistant and flexible material, and may be made of, for example, PP, PE, or water-resistant coated paper. The cap may further include an inner lid made of resin inside the cap body. The resin constituting the inner lid may be, for example, PP, PE, PET, POM, or polyvinyl chloride.

[0043] (2nd water-based ink) The second water-based ink 22 contains a second coloring material and water. The second aqueous ink 22 may further contain at least one of a water-soluble organic solvent, a pH adjuster, a viscosity adjuster, a preservative, and a second dispersant, as necessary. The pH adjuster, the viscosity adjuster, the preservative, and the second dispersant may be the same as the pH adjuster, the viscosity adjuster, the preservative, and the first dispersant in the first aqueous ink 5, respectively. The second coloring material may be an acid dye, a basic dye, a pigment, or a colored particle. The acid dye, the basic dye, the pigment, or the colored particle may be the same as the acid dye, the basic dye, the pigment, or the colored particle in the first water-based ink 5. Here, when the first coloring material is composed of an acid dye, the second coloring material is composed of an acid dye; when the first coloring material is composed of a basic dye, the second coloring material is composed of a basic dye; when the first coloring material is composed of a pigment, the second coloring material is composed of a pigment; and when the first coloring material is composed of colored particles, the second coloring material is composed of colored particles.

[0044] When the second coloring material is an acid dye or a basic dye, the content of the second coloring material is preferably 0.1 to 10.0 mass %, and more preferably 0.1 to 3.0 mass %, based on the total amount of the second water-based ink 22. When the second coloring material is a pigment, the content of the second coloring material is preferably 3.0 to 15.0 mass % based on the total amount of the second water-based ink 22, and more preferably 5.0 to 10.0 mass %.

[0045] (water) The water content is preferably 10.0 to 80.0 mass %, and more preferably 50.0 to 80.0 mass %, based on the total amount of the second water-based ink 22.

[0046] (Water-soluble organic solvent) The water-soluble organic solvent may be the same as or different from the water-soluble organic solvent contained in the first water-based ink 5, but is preferably the same. When the water-soluble organic solvent is different from the water-soluble organic solvent contained in the first water-based ink 5, it may or may not have components in common with the water-soluble organic solvent contained in the first water-based ink 5, but from the viewpoint of the temporal stability of the second water-based ink 22, it is preferable that it has such components. The content of the water-soluble organic solvent is preferably 5.0 to 50.0 mass % based on the total amount of the second water-based ink 22, and more preferably 10.0 to 30.0 mass %.

[0047] (pH adjuster) The pH adjuster may be the same as or different from the pH adjuster contained in the first water-based ink 5, but it is preferable that they are the same. When the pH adjuster is different from the pH adjuster contained in the first water-based ink 5, it may or may not have components in common with the pH adjuster contained in the first water-based ink 5, but from the viewpoint of the stability over time of the second water-based ink 22, it is preferable that they have a component. The content of the pH adjuster is preferably 0.1 to 5.0% by mass based on the total amount of the second water-based ink 22.

[0048] (Viscosity modifier) The viscosity modifier may be the same as or different from the viscosity modifier contained in the first water-based ink 5, but is preferably the same. When the viscosity modifier is different from the viscosity modifier contained in the first water-based ink 5, it may or may not have components in common with the viscosity modifier contained in the first water-based ink 5, but it is preferable for it to have one from the viewpoint of achieving a smoother color change in the gradation. The content of the viscosity modifier is preferably 0.1 to 15.0% by mass, and more preferably 0.1 to 10.0% by mass, based on the total amount of the second water-based ink 22. When the content of the viscosity modifier is 10.0% by mass or less, an excessive increase in the viscosity of the second water-based ink 22 tends to be suppressed, and clogging of the second water-based ink 22 at the pen tip 2 tends to be suppressed. On the other hand, when the content of the viscosity modifier is 0.1% by mass or more, an excessive decrease in the viscosity of the second water-based ink 22 tends to be suppressed, and ink leakage from the pen tip 2 tends to be suppressed.

[0049] (Preservatives) The preservative may be the same as or different from the preservative contained in the first water-based ink 5, but is preferably the same. When the preservative is different from the preservative contained in the first water-based ink 5, it may or may not have a component in common with the preservative contained in the first water-based ink 5, but is preferably present from the viewpoint of the stability over time of the second water-based ink 22. The content of the preservative is preferably 0.1 to 0.5 mass % based on the total amount of the second water-based ink 22, and more preferably 0.1 to 0.3 mass %.

[0050] (Second dispersant) The surfactant used as the second dispersant may or may not have the same hydrophilic group or hydrophilic structure as the surfactant contained in the first aqueous ink 5. From the viewpoint of the stability over time of the second aqueous ink 22 and prevention of backflow, however, it is preferable that the surfactant have the same hydrophilic group or hydrophilic structure as the surfactant contained in the first aqueous ink 5. The content of the surfactant is preferably 0.3 to 5.0 mass % based on the total amount of the second water-based ink 22, and more preferably 0.5 to 3.0 mass %.

[0051] The resin used as the second dispersant may be a resin polymerized using the same monomer as the resin contained in the first water-based ink 5, or a resin polymerized using a different monomer; however, from the viewpoint of the stability over time of the second water-based ink 22, it is preferable that the resin be a resin polymerized using the same monomer. The content of the resin is preferably 5.0 to 30.0% by mass, and more preferably 10.0 to 20.0% by mass, based on the total amount of the second water-based ink 22.

[0052] (viscosity) The viscosity of the second water-based ink 22 is preferably 3.0 to 11.0 mPa·s, and more preferably 3.0 to 6.0 mPa·s. When the viscosity is 3.0 mPa·s or more, when the pen tip 2 of the marker pen 10 is dipped in the second water-based ink 22 contained in the ink bottle 21 of the ink container 20 and writing on paper, the ink is less likely to bleed or show through, and the written lines are less likely to be smudged. When the pen tip 2 of the marker pen 10 is dipped in the second water-based ink 22 contained in the ink bottle 21 of the ink container 20 and writing on paper, the ink is less likely to bleed or show through, and the written lines are less likely to be smudged. The viscosity was measured at a temperature of 25°C and a shear rate of 225 s -1 This refers to the viscosity at

[0053] (viscosity difference) The difference in viscosity between the first water-based ink 5 and the second water-based ink 22 is not particularly limited, but is preferably 8.0 mPa·s or less. In this case, when the pen tip 2 of the marker pen 10 is dipped in the second water-based ink 22 contained in the ink bottle 21 of the ink container 20 and writing on paper, the ink is less likely to bleed or show through, and the written lines are less likely to fade, compared to when the viscosity difference exceeds 8.0 mPa·s. The viscosity difference is preferably 5.0 mPa·s or less, more preferably 2.5 mPa·s or less, and particularly preferably 0 mPa·s. The viscosity of the second water-based ink 22 may be greater than or less than the viscosity of the first water-based ink 5 , or may be the same as the viscosity of the first water-based ink 5 .

[0054] The second water-based ink 22 can be obtained by mixing the above-mentioned components using a stirrer such as a dissolver, a Henschel mixer, or a homomixer, in the same manner as the first water-based ink 5. The stirring conditions of the stirrer are not particularly limited, but for example, the second water-based ink 22 in which each component is uniformly dispersed can be obtained by stirring for 30 to 180 minutes at a rotation speed of 100 to 1000 rpm using a dissolver stirrer.

[0055] (3) Writing utensil set If the height from the bottom surface of main body 21a to the tip surface of mouth 21b is h (cm), the inner diameter of mouth 21b is y (cm), and the maximum outer diameter of marker pen 10 from tip 2 of marker pen 10 to height h is x (cm), then the ratio of y to x, R(y / x), is not particularly limited and may be 1.5 or more or less than 1.5, but is preferably 1.5 or more. In this case, when the tip 2 of the marker pen 10 is inserted into the ink bottle 21 and immersed in the second water-based ink 22, the liquid level of the second water-based ink 22 becomes more visible and the marker pen 10 can be easily tilted relative to the extension direction of the main body portion 21a within the ink bottle 21, making it possible to check the degree of adhesion of the second water-based ink 22 to the tip 2 while visually checking the tip 2. R is preferably 1.5 to 10, more preferably 1.5 to 6, and particularly preferably 1.5 to 3. EXAMPLES

[0056] The present invention will be specifically described below by way of examples, but the scope of the present invention is not limited to these.

[0057] [Preparation of the first water-based ink and the second water-based ink] Colorant, dispersant, viscosity modifier, preservative, water-soluble organic solvent and water were mixed to the contents (unit: mass %) shown in Table 1 to obtain acidic dye inks A and B, basic dye inks A and B, surfactant-dispersed pigment inks 1 A and B, surfactant-dispersed pigment inks 2 A and B, resin-dispersed pigment inks 1 A and B, resin-dispersed pigment inks 2 A and B, and colored particle inks A and B. Note that surfactant-dispersed pigment ink refers to an ink in which a pigment is dispersed in a surfactant, and resin-dispersed pigment ink refers to an ink in which a pigment is dispersed in a resin.

[0058] Details of the coloring material, dispersant, viscosity modifier, preservative, water-soluble organic solvent, and water used in preparing each ink are as follows. <Coloring material> (acid dye) CIAcid Red 18 (Tokyo Chemical Industry Co., Ltd., dye concentration: 85% by weight) Water Green 8 (Orient Chemical Industries Co., Ltd., dye concentration: 99% by weight) (Basic dyes) ·CIBasic Yellow 40 (manufactured by Career Henan Chemical, dye concentration: 98% by mass) ·CIBasic Blue 3 (manufactured by American Custom Chemicals, dye concentration: 95% by mass) (Pigments) CI Pigment Orange 13 (Tokyo Chemical Industry Co., Ltd., pigment concentration: 99% by weight) CI Pigment Green 7 (Tokyo Chemical Industry Co., Ltd., pigment concentration: 99% by weight) CI Pigment Red 9 (American Custom Chemicals, pigment concentration: 99% by weight) CI Pigment Blue 15 (Tokyo Chemical Industry Co., Ltd., pigment concentration: 99% by weight) (colored particles) LUMIKOL NKW-3205E (manufactured by Nippon Kinko Kagaku Co., Ltd., colored particle concentration: 37% by mass) LUMIKOL NKW-3208E (manufactured by Nippon Kinko Kagaku Co., Ltd., colored particle concentration: 37% by mass) <Dispersant> Demol EP (Kao Corporation, polycarboxylic acid type polymer surfactant) · Plysurf A215C (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl ether phosphate surfactant) Joncryl 61J (BASF, acrylic resin, resin concentration: 30.5% by mass, water content: 68.5% by mass, water-soluble organic solvent content: 1.0% by mass) FLOWLEN G-700DMEA (manufactured by Kyoeisha Chemical Co., Ltd., salt of modified resin containing carboxyl groups, resin concentration: 70% by mass) <Viscosity modifier> Kuraray Poval PVA-403 (Kuraray Co., Ltd., polymerization degree: 300, saponification degree: 80.0 mol%) <Preservatives> Topside 280 (thiolpyridine oxide salt, manufactured by PermaChem Asia Co., Ltd.) <Water-soluble organic solvent> Glycerin (manufactured by NOF Corporation) <Water> Ion-exchanged water

[0059] Example 1 A marker pen 10 as shown in Fig. 1 was prepared. Specifically, the inner padding 4 was impregnated with acid dye ink A, the pen tip 2 made of a polyester fiber tip (fiber bundle) was inserted into the inner padding 4, and the inner padding 4 and the pen tip 2 were attached to the shaft 3 and the center shaft 6 to prepare the marker pen 10. On the other hand, an ink bottle 21 shown in Fig. 1 was prepared. The ink bottle 21 was made of glass. The inner diameter y of the cylindrical mouth of the ink bottle was 1.8 cm. The height h from the bottom surface of the body to the tip of the mouth was 3.8 cm. Next, the acid dye ink B was placed in the ink bottle 21 . Thus, a set of writing implements was prepared.

[0060] (Examples 2 to 13 and Comparative Examples 1 to 31) A writing instrument set was prepared in the same manner as in Example 1, except that the ink combinations shown in Table 2 or Table 3 were used as the ink for the marker pen (first water-based ink) and the ink for the ink bottle (second water-based ink).

[0061] [Written Exam] The pen tip 2 of the marker pen 10 was immersed in the second water-based ink 22 in the ink bottle 21, and writing was continued on the paper until the lines written by the marker pen 10 returned to their original color. After that, the pen tip 2 and the lines written were visually observed under a stereomicroscope to check for the presence or absence of precipitates, aggregates, and residual color. The results are shown in Table 2 or Table 3. In Table 2 or Table 3, ◯ and × represent the following: ○: No precipitate, aggregates or color residue was observed on the pen tip or on the written line. ×: At least one of precipitates, aggregates, and color residues is observed on the pen tip or writing line. [Table 1]

[0062] [Table 2] [Table 3]

[0063] In the writing implement sets of Examples 1 to 13, no precipitate or aggregate was observed on the pen tip or on the writing line, and no color residue was observed. In contrast, in the writing implement sets of Comparative Examples 1 to 31, at least one of precipitate, aggregate, and color residue was observed on the pen tip or on the writing line.

[0064] From the above, it was confirmed that writing lines with gradation can be easily written in a short time, and deterioration of the usability of the marker pen can be suppressed. [Explanation of symbols]

[0065] 2...pen tip, 4...filling, 5...first water-based ink, 10...marker pen, 20...ink container, 21...ink bottle, 21a...main body, 21b...mouth, 22...second water-based ink, 100...writing instrument set.

Claims

1. A writing instrument set including a marker pen that contains a first water-based ink and ejects the ink through a pen tip, and an ink container having an ink bottle that contains a second water-based ink, the first water-based ink contains a first colorant, the second water-based ink contains a second colorant, the first color material and the second color material are composed of an acid dye, a basic dye, a pigment, or a colored particle, A writing instrument set, wherein when the second color material is composed of colored particles, the first color material is composed of an acid dye, a basic dye or a pigment.

2. the first color material and the second color material contain the pigment, the first water-based ink comprises a first dispersant; the second water-based ink comprises a second dispersant; The writing instrument set according to claim 1 , wherein the first dispersant and the second dispersant are composed of surfactants having the same hydrophilic group or hydrophilic structure, or resins polymerized using the same monomer.

3. The writing instrument set according to claim 1 or 2, wherein the pen tip of the marker pen is composed of a fiber tip, a porous tip or a plastic tip.

4. 3. The writing instrument set according to claim 1, wherein the first water-based ink and the second water-based ink have a viscosity of 3.0 to 11.0 mPa·s.

5. The writing instrument set according to claim 1 , wherein a difference in viscosity between the first water-based ink and the second water-based ink is 8.0 mPa·s or less.

6. the ink bottle comprises a main body having a bottom surface and a cylindrical mouth portion connected to the main body; 3. The writing instrument set of claim 1, wherein the height from the bottom surface of the main body to the tip surface of the mouth is h (cm), the inner diameter of the mouth is y (cm), and the maximum outer diameter of the marker pen from the tip of the marker pen to height h is x (cm), and the ratio R(y / x) of y to x is 1.5 or greater.

7. A method of using the writing instrument set according to claim 1 or 2, comprising: A method of using a writing instrument set, comprising a step of immersing the tip of the marker pen of the writing instrument set in the second water-based ink contained in the ink bottle of the ink container and writing on a surface of an object to be written on.

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