Aqueous ink composition and marking pen

Abstract

To provide an aqueous ink composition for a marking pen which is capable of reducing repelling of writing lines when writing on non-porous surfaces, while reducing blurring and bleed-through of writing lines when writing on paper surfaces, and also can prevent ink leakage from the marking pen.SOLUTION: An aqueous ink composition for a marking pen comprises at least a colorant, a resin, a surfactant, a water-soluble organic solvent, and water, the surfactant including a succinic acid-based surfactant, the content of the succinic acid-based surfactant being 0.05 to 3.0 mass% relative to the total amount of the aqueous ink composition, the aqueous ink composition having a viscosity of 2.7 to 7.0 mPa s at 25°C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an aqueous ink composition and a marking pen. [Background technology]

[0002] 2. Description of the Related Art Conventionally, ink compositions containing a wetting agent such as a fluorine-based surfactant have been known as aqueous ink compositions for marking pens capable of writing on non-permeable surfaces (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-143417 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for a marking pen that can be used for writing on both non-permeable surfaces and paper surfaces. Such a marking pen is required to be able to write on non-permeable surfaces (non-absorbent surfaces) without causing repelling, and also to be able to write on paper surfaces without causing smearing and to be unlikely to cause bleed-through. In addition, there is a demand for the marking pen to be unlikely to leak ink after being filled with an ink composition. Furthermore, from the viewpoint of environmental regulations, there is a demand for a marking pen that uses as little fluorosurfactants as possible.

[0005] The present invention aims to provide an aqueous ink composition for a marking pen, which can reduce repelling of a writing line when written on a non-permeable surface, can reduce smearing and show-through of a writing line when written on a paper surface, and can suppress ink leakage from the marking pen, and a marking pen using the same. [Means for solving the problem]

[0006] To achieve the above object, the present disclosure provides the following aqueous ink composition and marking pen. [1] An aqueous ink composition for a marking pen containing at least a colorant, a resin, a surfactant, a water-soluble organic solvent, and water, wherein the surfactant contains a succinic acid-based surfactant, and the content of the succinic acid-based surfactant is 0.05 to 3.0% by mass based on the total amount of the aqueous ink composition, and the viscosity of the aqueous ink composition at 25 ° C is 2.7 to 7.0 mPa·s. [2] The aqueous ink composition according to [1] above, wherein the surfactant does not contain a fluorine-based surfactant. [3] The aqueous ink composition according to [1] or [2] above, which is for a marking pen provided with medium cotton having a fiber thickness of 2 to 5 denier and a porosity of 90% or less. [4] A marking pen containing the aqueous ink composition according to any one of [1] to [3] above. [5] The marking pen according to [4] above, which is provided with medium cotton having a fiber thickness of 2 to 5 denier and a porosity of 90% or less.

Advantages of the Invention

[0007] According to the present invention, it is an object to provide an aqueous ink composition for a marking pen that can reduce the repelling of the writing line when writing on a non-permeable surface, can reduce the streaking of the writing line and the bleeding through of the writing line when writing on paper, and can suppress ink leakage from the marking pen, and a marking pen using the same.

Brief Description of the Drawings

[0008] [Figure 1] It is a schematic cross-sectional view showing an embodiment of a marking pen according to the present invention.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary.

[0010] [Water-based ink composition] The aqueous ink composition of the present embodiment (hereinafter also referred to as "ink composition") is an ink composition for a marking pen, and contains at least a colorant, a resin, a surfactant, a water-soluble organic solvent, and water. Each component will be described below.

[0011] (Coloring agent) The colorant may be a dye or a pigment. The dye is preferably a water-soluble dye. Examples of the water-soluble dye include direct dyes, acid dyes, and basic dyes. The pigment is preferably a water-dispersible pigment. The colorant may be used alone or in combination of two or more.

[0012] Examples of pigments include inorganic pigments such as carbon black and ultramarine, organic pigments such as copper phthalocyanine blue and benzidine yellow, and water-dispersed pigment products in which various pigments are finely and stably dispersed in an aqueous medium. Examples of water-dispersed pigment products include water-dispersed pigment products in which pigments are dispersed in an aqueous medium using a surfactant or a water-soluble resin, water-dispersed pigment products in which pigments to which self-dispersibility has been imparted are dispersed in an aqueous medium, and water-dispersed pigment products in which synthetic resin particles colored with various dyes are dispersed in an aqueous medium. Among these, water-dispersed pigment products in which pigments to which self-dispersibility has been imparted are dispersed in an aqueous medium, and water-dispersed pigment products in which synthetic resin particles colored with various dyes are dispersed in an aqueous medium, from the viewpoint of storage stability. Here, examples of pigments to which self-dispersibility has been imparted include pigments in which polar groups such as carboxyl groups and hydroxyl groups are retained on the surface by treating the surface with an oxidizing agent such as nitric acid, ozone, and hydrogen peroxide.

[0013] Examples of water-dispersed pigment products in which a pigment is dispersed in an aqueous medium using the above-mentioned surfactants include Sandye Super Blue GLL (manufactured by Sanyo Pigment Co., Ltd., CI Pigment Blue 15:3B, pigment content 24% by mass), Sandye Super Pink FBL (manufactured by Sanyo Pigment Co., Ltd., CI Pigment Red 146, pigment content 21.5% by mass), TC Yellow FG (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., CI Pigment Yellow 81, pigment content approximately 30% by mass), and TC Red FG (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., CI Pigment Red 220 / 166, pigment content approximately 35% by mass).

[0014] Examples of water-dispersed pigment products in which a pigment is dispersed in an aqueous medium using the above-mentioned water-soluble resin include WA color Black A 250 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., CI Pigment Black 7, pigment content 15% by mass), WA-S color Green (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., CI Pigment Green 7, pigment content 8% by mass), Micropigmo WMVT-5 (manufactured by Orient Chemical Industry Co., Ltd., CI Pigment Violet 23, pigment content 20% by mass), and Emacol NS Yellow 4618 (manufactured by Sanyo Pigment Co., Ltd., CI Pigment Yellow 83, pigment content 30% by mass).

[0015] Examples of water-dispersed pigment products in which the self-dispersible pigment is dispersed in an aqueous medium include Fuji Jet Black (manufactured by Fuji Pigment Co., Ltd., CI Pigment Black 7, pigment content 15% by mass), Fuji Jet Black A-20 (manufactured by Fuji Pigment Co., Ltd., CI Pigment Black 7, pigment content 20% by mass), Fuji Jet Black B-15 (manufactured by Fuji Pigment Co., Ltd., CI Pigment Black 7, pigment content 15% by mass), Fuji Jet Black B-22 (manufactured by Fuji Pigment Co., Ltd., CI Pigment Black 7, pigment content 22% by mass), BON JET BLACK CW-1 (manufactured by Orient Chemical Industry Co., Ltd., CI Pigment Black 7, pigment content 20% by mass), BON JET BLACK CW-2 (manufactured by Orient Chemical Industry Co., Ltd., CI Pigment Black 7, pigment content 15% by mass), BON JET BLACK CW-3 (manufactured by Orient Chemical Industry Co., Ltd., CI Pigment Black 7, pigment content 15% by mass), and BON JET BLACK CW-4 (manufactured by Orient Chemical Industry Co., Ltd., CI Pigment Black 7, pigment content 15% by mass). Examples of suitable pigments include CI Pigment Black 7, pigment content 13% by mass, Aqua Black 162 (manufactured by Tokai Carbon Co., Ltd., CI Pigment Black 7, pigment content 20% by mass), and Aquq Black 001 (manufactured by Tokai Carbon Co., Ltd., CI Pigment Black 7, pigment content 20% by mass).

[0016] Further, examples of water-dispersed pigment products in which synthetic resin particles colored with the above-mentioned various dyes are dispersed in an aqueous medium include the NKW-2100E series (manufactured by Nippon Kinko Kagaku Co., Ltd., non-volatile content 51% by mass), the NKW-3200E series (manufactured by Nippon Kinko Kagaku Co., Ltd., non-volatile content 37% by mass), the NKW-C2100E series (manufactured by Nippon Kinko Kagaku Co., Ltd., non-volatile content 50±3% by mass), the NKW-6000E series (manufactured by Nippon Kinko Kagaku Co., Ltd., non-volatile content 34±3% by mass), the NKW-6200E series (manufactured by Nippon Kinko Kagaku Co., Ltd., non-volatile content 48 to 54% by mass), and SW-1 Examples of such pigments include the SF-00 series (manufactured by Shin-Roi-Hi Co., Ltd., solid content 42±1% by mass), the SF-3000N series (manufactured by Shin-Roi-Hi Co., Ltd., solid content 40±1.5% by mass), the SF-5000 series (manufactured by Shin-Roi-Hi Co., Ltd., solid content 30±1.5% by mass), the SF-8000 series (manufactured by Shin-Roi-Hi Co., Ltd., solid content 50±2% by mass), the SP-10 series (manufactured by Shin-Roi-Hi Co., Ltd., pigment content approximately 40% by mass), the SG-500 series (manufactured by Shin-Roi-Hi Co., Ltd., pigment content approximately 60% by mass), and the FW-8500KS series (manufactured by Shin-Roi-Hi Co., Ltd., solid content approximately 55% by mass).

[0017] When only a pigment is used as the colorant, the content of the colorant is preferably 2 to 25% by mass, more preferably 2.5 to 20% by mass, based on the total amount of the ink composition. When this content is equal to or more than the lower limit, the visibility of the written lines can be improved, and when it is equal to or less than the upper limit, the viscosity of the ink composition can be reduced, and the dischargeability of the ink composition from the marking pen tends to be maintained. In this specification, the content of the colorant means the content of the non-volatile matter in the colorant.

[0018] When only a dye is used as the colorant, the content of the colorant is preferably 1 to 15 mass %, more preferably 2 to 10 mass %, based on the total amount of the ink composition. By making this content equal to or more than the lower limit, the visibility of the written lines can be further improved, and by making this content equal to or less than the upper limit, the bleed-through of the written lines when written on paper can be further reduced.

[0019] When a pigment and a dye are used in combination as colorants, the pigment content is preferably 1 to 25 mass % and the dye content is preferably 2 to 20 mass % based on the total amount of the ink composition. When this content is equal to or more than the lower limit, the visibility of the written lines can be further improved, and when it is equal to or less than the upper limit, the viscosity of the ink composition can be reduced, and the dischargeability of the ink composition from the marking pen tends to be maintained.

[0020] (resin) The resin functions as a fixing agent. Examples of the resin include a resin having a structural unit derived from (meth)acrylic acid, a urethane resin, a styrene-butadiene resin, etc. The resin may be used alone or in combination of two or more kinds.

[0021] The resin having a structural unit derived from (meth)acrylic acid is a resin obtained by, for example, radical polymerization of a monomer containing (meth)acrylic acid, etc. (i.e., acrylic acid or methacrylic acid, or a derivative thereof). The resin having a structural unit derived from (meth)acrylic acid may be a homopolymer of the above-mentioned (meth)acrylic acid, etc., a copolymer of two or more kinds of (meth)acrylic acid, etc., or a copolymer of the above-mentioned (meth)acrylic acid, etc., and a monomer different from the above-mentioned (meth)acrylic acid, etc. Examples of the monomer different from the above-mentioned (meth)acrylic acid, etc. include styrene, butadiene, acrylonitrile, and derivatives thereof. The monomer different from the above-mentioned (meth)acrylic acid, etc. is preferably styrene or α-methylstyrene. When the resin having a structural unit derived from (meth)acrylic acid is a copolymer of (meth)acrylic acid, etc., and a monomer different from (meth)acrylic acid, etc., such as styrene, it can also be referred to as a resin having a structural unit derived from (meth)acrylic acid and a structural unit derived from styrene.

[0022] The content of the resin (solid content) is preferably 1.0 to 15% by mass, more preferably 1.5 to 10% by mass, based on the total amount of the ink composition. When the content of the resin is equal to or more than the lower limit, the adhesion of the written lines can be improved when the ink is written on a non-permeable surface, and the bleed-through of the written lines when the ink is written on a paper surface tends to be reduced. When the content of the resin is equal to or less than the upper limit, the viscosity of the ink composition can be reduced, the dischargeability of the ink composition from a marking pen is maintained, and the smearing of the written lines when the ink is written on a paper surface tends to be reduced.

[0023] (Surfactant) The surfactant includes a succinic acid surfactant. Examples of succinic acid surfactants include dialkyl sulfosuccinic acid and salts of dialkyl sulfosuccinic acid. The dialkyl sulfosuccinic acid or salts of dialkyl sulfosuccinic acid are not particularly limited, and both synthesized and commercially available ones can be used. Examples of commercially available dialkyl sulfosuccinic acid or salts of dialkyl sulfosuccinic acid include sodium bis(2-ethylhexyl) sulfosuccinate (manufactured by Tokyo Chemical Industry Co., Ltd., active ingredient 100% by mass), Sanmorin OT (manufactured by Sanyo Chemical Industries Co., Ltd., active ingredient 70% by mass), Carabon DA-72 (manufactured by Sanyo Chemical Industries Co., Ltd.), Pelex OT-P (manufactured by Kao Corporation, active ingredient 70% by mass), Air Roll CT-1 (Toho Chemical Industry Co., Ltd., active ingredient 70% by mass), and Ripearl 860K (manufactured by Lion Specialty Chemicals Co., Ltd., active ingredient 60% by mass). The term "active ingredient" refers to the mass ratio of the surfactant excluding components other than the surfactant such as solvents. Examples of succinic acid surfactants other than dialkyl sulfosuccinic acid and salts of dialkyl sulfosuccinic acid include monolauroyl monoethanolamide polyoxyethylene sulfosuccinate sodium, lauryl polypropylene glycol sulfosuccinate sodium, etc. The succinic acid surfactants can be used alone or in combination of two or more.

[0024] The content of the succinic acid surfactant is 0.05 to 3.0% by mass based on the total amount of the ink composition. When the content is 0.05% by mass or more, repelling of the written line when written on a non-permeable surface can be reduced, and when the content is 3.0% by mass or less, show-through of the written line when written on a paper surface can be reduced. From the viewpoint of obtaining the above effect more fully, the content of the succinic acid surfactant is preferably 0.1 to 2.0% by mass based on the total amount of the ink composition.

[0025] The surfactant may contain other surfactants other than the succinic acid surfactant. Examples of other surfactants include silicon surfactants, acetylene glycol surfactants, and sodium alkylnaphthalenesulfonate. However, from the viewpoint of environmental regulations, it is preferable that the surfactant does not contain a fluorine-based surfactant.

[0026] Specific examples of silicone surfactants include KF-351, KF-352, KF-353, KF-354, KF-355, KF-615, KF-618, KF-642, KF643, KF945, and KF-6004 (all manufactured by Shin-Etsu Chemical Co., Ltd.), SILWETL-720, FZ-2104, FZ-2191, L-7001, L-7002, Y-7006, L-7600, and L-7607 (all manufactured by Nippon Unicar Co., Ltd.), TSF4445 (all manufactured by Toshiba Silicones Co., Ltd.), BYK-333, BYK-347, and BYK-349 (all manufactured by BYK Japan KK).

[0027] Specific examples of acetylene glycol surfactants include Olfine D-10A, Olfine D-10PG, Olfine E1004, Olfine E1010, Olfine E1020, Olfine E1030W, Olfine PD-001, Olfine PD-002W, Olfine PD-003, Olfine PD-004, Olfine PD-201, Olfine PD-301, Olfine EXP.4001, Olfine EXP.4200, Olfine EXP.4123, Olfine EXP.4300, Surfynol 82, Surfynol 104E, Surfynol 104H, Examples of such an agent include Surfynol 104A, Surfynol 104PA, Surfynol 104PG-50, Surfynol 104S, Surfynol 420, Surfynol 440, Surfynol 465, Surfynol 485, Surfynol 2502, Dynol 604, Dynol 607 (all manufactured by Nissin Chemical Industry Co., Ltd.), Acetylenol E13T, Acetylenol EH, Acetylenol EL, Acetylenol E40, Acetylenol E60, Acetylenol E81, Acetylenol E100, and Acetylenol 85 (all manufactured by Kawaken Fine Chemicals Co., Ltd.).

[0028] The content of the succinic acid surfactant in the surfactant is not particularly limited, but may be, for example, 20 mass % or more based on the total amount of the surfactant.

[0029] (Water-soluble organic solvent) Examples of the water-soluble organic solvent include glycerin, propylene glycol, ethylene glycol, and diethylene glycol. When the ink composition contains the water-soluble organic solvent, the ink composition tends to have a moisturizing effect. The content of the water-soluble organic solvent is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, based on the total amount of the ink composition.

[0030] (water) The ink composition of the present embodiment contains water as an aqueous solution or aqueous dispersion of the above-mentioned components, or in addition to the above-mentioned components. The content of water is preferably 50 to 90 mass %, more preferably 60 to 80 mass %, based on the total amount of the ink composition.

[0031] (Additives) In addition to the components described above, the ink composition of this embodiment may contain additives such as a dry-up inhibitor, an anti-rust agent, a pH adjuster, a thickener, an antiseptic (antifungal agent), a lubricant, and a pigment dispersant.

[0032] Examples of the dry-up inhibitor include 1,4-cyclohexanedimethanol, urea, etc. When the ink composition contains a dry-up inhibitor, the content of the dry-up inhibitor is preferably 0.5 to 10 mass %, and more preferably 1 to 5 mass %, based on the total amount of the ink composition, from the viewpoint of the dry-up inhibitory effect.

[0033] The ink composition of the present embodiment 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, an ink composition in which the components are 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.

[0034] The viscosity of the ink composition of this embodiment at 25°C is 2.7 to 7.0 mPa·s. When the viscosity is 2.7 mPa·s or more, it is possible to suppress ink leakage from the marking pen after filling with the ink composition. On the other hand, when the viscosity is 7.0 mPa·s or less, it is possible to reduce blurring of written lines when writing on paper. From the viewpoint of more fully obtaining the above effects, it is preferable that the viscosity of the ink composition at 25°C is 2.8 to 6.0 mPa·s.

[0035] The viscosity of the ink composition at 25° C. can be measured using an E-type viscometer at 25° C. and a 0.8°×R24 cone plate at a rotation speed of 30 rpm.

[0036] [Marking pen] The marking pen of the present embodiment comprises a pen tip made of a fiber core or a plastic core, and an ink reservoir, in which the above-mentioned ink composition is contained.

[0037] FIG. 1 is a cross-sectional view of a marking pen according to an embodiment of the present invention. The marking pen 10 in FIG. 1 is a batting type. The marking pen 10 in FIG. 1 has a pen tip at both ends, but may have a pen tip at only one end. The marking pen 10 in FIG. 1 has an ink storage section 1, pen tips 2a, 2b, a shaft 3, a batting 4, and caps 5a, 5b. In the marking pen 10, the space inside the shaft 3 serves as the ink storage section 1, and the batting 4 containing the ink composition of this embodiment is stored in this ink storage section 1. Note that a cylindrical central shaft may be provided inside the shaft 3 in addition to the shaft 3, and the space inside the central shaft may serve as the ink storage section 1.

[0038] The pen tips 2a and 2b are typical marking pen tips and are formed of fiber or plastic cores capable of supplying an ink composition. In the marking pen 10, the tip shape of the pen tips 2a and 2b is bullet-shaped. In the marking pen 10, the tip shape of the pen tips 2a and 2b is not limited to a bullet shape, and may be a chisel shape, a brush pen shape, or the like.

[0039] Moreover, the caps 5a and 5b are disposed so as to cover the pen tips 3a and 3b, respectively.

[0040] In the filling 4, the fiber thickness is preferably 2 to 5 denier. By having the fiber thickness within the above range, when the ink composition of this embodiment is filled into an ink storage section, it is possible to suppress ink leakage from the pen tip of a marking pen. The thickness of the fibers constituting the filling 4 can be adjusted, for example, by selecting the diameter of the fiber (yarn) used to produce the filling 4.

[0041] The porosity of the filling 4 is preferably 90% or less, and more preferably 80 to 88%. When the porosity is within the above range, it is possible to prevent ink leakage from the pen tip of a marking pen when the ink composition of this embodiment is filled into an ink storage section. For example, the porosity of the filling 4 can be reduced by increasing the fiber weight per fiber of the filling, and the porosity of the filling 4 can be increased by decreasing the fiber weight.

[0042] The marking pen of the present embodiment is suitably used for writing on non-permeable surfaces such as glass plates, resin plates and metal plates, as well as for writing on paper. EXAMPLES

[0043] The present invention will be specifically described below by way of examples, but the scope of the present invention is not limited to these.

[0044] [Preparation of Water-Based Ink Composition] (Examples 1 to 14 and Comparative Examples 1 to 5) The materials shown in Tables 1 and 2 below were mixed to obtain water-based ink compositions of Examples 1 to 14 and Comparative Examples 1 to 5. The units of values ​​in the tables are parts by mass unless otherwise specified.

[0045] Details of each material in Tables 1 and 2 are as follows:

[0046] (Coloring agent) Carbon black aqueous dispersion (manufactured by Dainichiseika Chemicals Mfg. Co., Ltd., carbon black content: 13.0% by mass) Processed pigment aqueous dispersion (manufactured by Nippon Kasei Kagaku Co., Ltd., product name: Lumikol NKW-6503E (red), processed pigment content: 32% by mass) Organic pigment aqueous dispersion (manufactured by Clariant Chemicals, product name: Hostafine Magenta E30, organic pigment (CI Pigment Red 122) content: 20% by mass) (resin) Styrene-acrylic resin aqueous solution (manufactured by Toho Chemical Industry Co., Ltd., product name: BY-1383N, solid content: 25% by mass) (Surfactant) Succinic acid surfactant (manufactured by Sanyo Chemical Industries, Ltd., product name: Sanmorin OT-70, chemical name: sodium bis(2-ethylhexyl) sulfosuccinate, active ingredient: 70% by mass, propylene glycol: 16% by mass, water: 14% by mass) Silicone surfactant (manufactured by BYK Japan, product name: BYK-349, active ingredient: 100% by mass) Acetylene-based surfactant (manufactured by Nissin Chemical Industry Co., Ltd., product name: Olfin EXP.4123, active ingredient: 40% by mass, propylene glycol: 50% by mass, water: 10% by mass) Sodium alkylnaphthalenesulfonate (Kao Corporation, product name: Pelex NBL, active ingredient: 35% by weight, water: 75% by weight) (Preservatives) BIT-based preservative (Osaka Gas Chemicals, product name: Srout 99N, chemical name: 1,2-benzisothiazolin-3-one) (rust inhibitor) Benzotriazole-based rust inhibitor (manufactured by Chelesto, product name: Colomi CB)

[0047] [Evaluation of Ink Composition] The ink compositions obtained in Examples 1 to 14 and Comparative Examples 1 to 5 were filled into the batting of an ink storage section of a marking pen having the structure shown in FIG. 1, and the ink composition was soaked into the pen tip. A bullet-shaped polyester fiber core was used for the pen tip. The batting was made of polyester fibers having the fiber diameters and porosities shown in Tables 1 and 2. The ink compositions and marking pens obtained were used to carry out the evaluations described below. The evaluation results are shown in Tables 1 and 2.

[0048] (Measurement of Viscosity) The viscosity of the obtained ink composition was measured using an E-type viscometer at 25 °C with a 0.8°×R24 cone plate at a rotational speed of 30 rpm.

[0049] (Writability on Paper) Using the obtained marking pen, a straight line was written on copy paper. The scratching condition of the written line was visually confirmed, and the writability was evaluated according to the following evaluation criteria. A: There was no scratching on the written line, and the writability was good. B: There was slight scratching on the written line, but the writability was generally good. C: Scratching occurred on the written line, and the writability was poor. D: The degree of scratching on the written line was large, and a clear written line could not be written, and the writability was greatly inferior.

[0050] (Anti-Scumming Property during Writing on a Non-Permeable Surface) Using the obtained marking pen, characters (the character "East") were written on a clear file (made of PP). The scumming condition of the written line was visually confirmed, and the anti-scumming property was evaluated according to the following evaluation criteria. A: There was no scumming on the written line, and the anti-scumming property was good. B: There was slight scumming on the written line, but the anti-scumming property was generally good. C: Scumming occurred on the written line, and the anti-scumming property was poor. D: Scumming occurred throughout the written line, and a clear written line could not be written, and the anti-scumming property was greatly inferior.

[0051] (Anti-Bleeding Property during Writing on Paper) Using the obtained marking pen, characters (the character "East") were written on copy paper. The back side of the paper was visually inspected, and the anti-bleeding property of the written line was evaluated according to the following evaluation criteria. A: There was no bleeding of the written line, and the anti-bleeding property was good. B: Slight bleeding of the written line occurred, but the anti-bleeding property was generally good. C: Strike-through of the written lines occurred, and resistance to Strike-through was poor. D: The degree of strike-through of the written lines was large, and the strike-through resistance was significantly poor.

[0052] (Ink leakage test) The obtained marking pen was set on the tip of a 500 mm long arm of a pendulum tester (manufactured by Zebra Corporation) with the pen tip facing downward and the cap attached. Next, the arm was swung from a position directly below (0°) to a position of 45° to the left and right continuously rising (as if drawing an arc). The swing speed was set to a speed at which the arm made 10 reciprocating movements in 9 seconds. After the 10 reciprocating movements, the cap of the marking pen was removed, and the inside of the cap and around the pen tip were visually checked for ink leakage, and ink leakage was evaluated according to the following evaluation criteria. A: There was no ink leakage. B: There was a slight ink leak. C: There was an ink leak. D: The amount of ink leakage was significant.

[0053] [Table 1]

[0054] [Table 2] [Explanation of symbols]

[0055] Reference Signs List 1: ink storage section; 2a, 2b: pen tip; 3: barrel; 4: batting (ink composition); 5a, 5b: cap; 10: marking pen.

Claims

1. An aqueous ink composition for a marking pen, comprising at least a colorant, a resin, a surfactant, a water-soluble organic solvent, and water, the surfactant comprises a succinic acid surfactant, the content of the succinic acid surfactant is 0.05 to 3.0% by mass based on the total amount of the aqueous ink composition; The aqueous ink composition has a viscosity of 2.7 to 7.0 mPa·s at 25° C.

2. The aqueous ink composition of claim 1 , wherein the surfactant is free of a fluorosurfactant.

3. 2. The aqueous ink composition according to claim 1, which is for use in a marking pen having a fiber thickness of 2 to 5 denier and a porosity of 90% or less.

4. A marking pen comprising the aqueous ink composition according to any one of claims 1 to 3.

5. 5. The marking pen according to claim 4, further comprising a padding having a fiber thickness of 2 to 5 denier and a porosity of 90% or less.

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