JP2019081899A - Aqueous ink composition for writing instruments and ink cartridge including the same, and writing instrument using the same - Google Patents

Abstract

To provide an aqueous ink composition for writing instruments and an ink cartridge including the same, and a writing instrument using the same.SOLUTION: An aqueous ink composition is included in a writing instrument having an ink cartridge in a detachable manner. The aqueous ink composition at least contains water, a colorant, and an acetylene glycol surfactant or acetylene alcohol surfactant. The contact angle of the aqueous ink composition to polyethylene is 40-100°, and the fall angle is 10-65°, and the contact angle of the aqueous ink composition to polymethylpentene is 45-90°, and the fall angle is 10-45°.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous ink composition for writing instruments and an ink cartridge containing the same. More specifically, the present invention relates to a water-based ink composition having excellent ink transferability, an ink cartridge incorporating the same, and a direct writing pen using these.

  Conventionally, a writing instrument that can be refilled with ink is known. As a refilling method thereof, a method of refilling ink by mounting an ink storage container filled with ink to an ink storage unit, or an ink storage container that doubles as an ink inhaler A system in which the ink is replenished by being attached to the ink storage unit, sucking the ink from the pen point and filling the ink storage container with the ink is used. In such writing instruments, in addition to an ink storage container called an ink cartridge, many parts are made of a synthetic resin, and the ink used contains an additive that increases the wettability to these components. ing. (Patent Document 1)

  Patent Document 1 describes an aqueous ink composition containing cyclodextrin. This ink enhances the wettability of the ink to the synthetic resin so that the movement of the ink (ink transferability) in the ink cartridge can be smoothly performed.

  However, when the ink composition of Patent Document 1 is used for a fountain pen provided with an ink cartridge, the mobility of the ink composition in the ink cartridge is not yet sufficient, and the ink cartridge has an orientation depending on the direction of the fountain pen. When the ink composition changes, the ink composition does not move smoothly, the ink supply to the pen point becomes insufficient, and the ink dischargeability may decrease.

Unexamined-Japanese-Patent No. 5-140498

  The present invention, when used in a writing instrument on which an ink cartridge is mounted, can smoothly move the inside of the ink cartridge while being able to suppress ink leakage from the pen tip during storage, resulting in good ink ejection performance. It is an object of the present invention to provide an aqueous ink composition for a writing instrument capable of forming a handwriting excellent in color development, an ink cartridge containing the same, and a writing instrument using the same.

The present invention solves the above problems by:
1. An aqueous ink composition incorporated in a writing instrument having a removable ink cartridge, comprising at least water, a colorant, and an acetylene glycol surfactant or an acetylene alcohol surfactant, for polyethylene The contact angle of the aqueous ink composition is 40 to 100 °, the falling angle is 10 to 65 °, and the contact angle of the aqueous ink composition to polymethylpentene is 45 to 90 °, the falling angle The water-based ink composition for writing materials whose 10 is 45 degrees.
2. An ink cartridge comprising the water-based ink composition for writing instruments described in item 1.
3. The ink cartridge according to claim 2, wherein the material is polyethylene or polymethylpentene.
4. The bottomed cylindrical body having an orthogonal cross section orthogonal to the longitudinal direction having a circular shape, and having a length of 40 to 80 mm in the longitudinal direction and a diameter of 2 to 8 mm as inner dimensions The ink cartridge according to any one of the above.
5. A writing instrument comprising the ink cartridge described in item 4.
6. In the writing instrument, a pen point, a detachable ink cartridge, and a number of disc bodies are arranged in parallel with a comb-like groove spaced from each other, and a slit-like ink guiding groove longitudinally penetrating the disc body It is a direct liquid type writing instrument comprising: a pen core having a wide-width venting groove, and an ink lead core for guiding ink from the ink storage portion to the pen tip in the axial center. Writing instrument.
7. 7. The writing instrument according to claim 6, wherein the direct solution writing instrument is a fountain pen. "

  The ink cartridge according to the present invention is characterized in that it contains the aqueous ink composition for writing instruments.

  A writing instrument according to the present invention is characterized in that the ink cartridge is accommodated.

  When used in a writing instrument equipped with an ink cartridge, it is possible to smoothly move the inside of the ink cartridge while being able to suppress ink leakage from the pen tip during storage, and to exhibit excellent ink dischargeability to develop coloring There is provided a water-based ink composition for a writing instrument capable of forming excellent handwriting, an ink cartridge incorporating the same, and a writing instrument using these.

  Hereinafter, embodiments of the present invention will be described in detail. In the present specification, “parts”, “%”, “ratios” and the like indicating the composition are on a mass basis unless otherwise specified.

  An aqueous ink composition for a writing instrument according to the present invention (hereinafter sometimes referred to as "aqueous ink composition" or "composition") comprises water, a colorant, an acetylene glycol surfactant or acetylene. And at least an alcohol surfactant. Hereinafter, each component which comprises the water-based ink composition for writing by this invention is demonstrated.

(Colorant)
The colorant used in the present invention can be optionally selected from conventionally known pigments and dyes, and can be preferably used. As the pigment, azo pigments, indigo pigments, phthalocyanine pigments, quinacridone pigments, thioindigo pigments, slen pigments, perinone pigments, perylene pigments, phthalone pigments, phthalon pigments, dioxane pigments, isoindolinone pigments, Organic pigments such as metal complex pigments, methine / azomethine pigments, and diketopyrrolopyrrole pigments can be mentioned.
It is also possible to use a pigment dispersion obtained by dispersing the pigment in a solvent. Examples of pigment dispersions used in the present invention include SP series (manufactured by Fuji Shiki Co., Ltd.), SANDYESPERCOLOUR series (manufactured by Sanyo Dye Co., Ltd.), EMACOL series (manufactured by Sanyo Dye Co., Ltd.), Lumicol series (manufactured by Nippon Fluorescent Chemical Co., Ltd.) MICROPROGMO series (manufactured by Orient Chemical Industries, Ltd.), WA series (manufactured by Dainichi Seika Kogyo Co., Ltd.), and the like.
The pigment may be coated on the surface of the pigment with a metal oxide such as aluminum oxide, zinc oxide, titanium oxide, or zirconium oxide, an inorganic oxide such as silicon dioxide, or a fatty acid.
Dyes include acid dyes, basic dyes, direct dyes, reactive dyes, vat dyes, sulfur dyes, metal-containing dyes, cationic dyes, and disperse dyes.
Among the colorants described above, the composition of the present invention preferably uses a dye. This is because the pigment is likely to affect the ink dischargeability and the color development of the handwriting by settling.

  It is preferable to set it as 0.1-20 mass% with respect to the ink composition whole quantity, and, as for content of the coloring agent in this invention, it is more preferable to set it as 1-10 mass%. When the content of the coloring agent is in the above range, it is possible to form a handwriting having good color development.

(Surfactant)
In the aqueous ink composition of the present invention, an acetylene glycol surfactant or an acetylene alcohol surfactant is essential as a surfactant. When the composition of the present invention contains the above-mentioned surfactant, the wettability and slipperiness of the composition to the ink cartridge are improved, and the ink composition can be smoothly moved in the ink cartridge, and from the ink cartridge Since the wettability of the ink composition with respect to the ink induction core for inducing the ink to the pen tip becomes good, it becomes possible to make the ink discharge property good. Moreover, although the reason is not clear, the writing instrument using the ink composition of the present invention can be a writing instrument having good ink dischargeability but suppressing ink leakage from the pen tip during storage.
The slipperiness means the flowability of the liquid on the solid surface, and in the present invention, the flowability of the ink composition on the surface of the ink cartridge.
In addition, since the acetylene glycol surfactant or the acetylene alcohol surfactant is excellent in the defoaming property, the ink composition of the present invention using the same tends to lose bubbles, and the ink composition in the ink cartridge is It has the feature that visibility becomes good.

ここで、Ｒ_１〜Ｒ_４は炭化水素基を示し、Ｒ_５はエチレン基を示す。
ｍ、ｐは０以上の整数である。 (Acetylene glycol surfactant)
The acetylene glycol surfactant in the present invention has a structure of the following general formula (1).

Here, R _{1 to} R _{4 each} represent a hydrocarbon group, and R ₅ represents an ethylene group.
m and p are integers of 0 or more.

The acetylene glycol surfactant used in the present invention has an m + p of 0 ≦ m + p in the chemical formula 1 in consideration of the wettability and sliding property to the ink cartridge, and the dissolution stability to the ink composition. It is preferably ≦ 30, and more preferably 0 ≦ m + p ≦ 20. The HLB value of the acetylene glycol surfactant is preferably 4 to 18, more preferably 8 to 17, and particularly preferably 12 to 16.
Here, the HLB value of the surfactant used in the present embodiment is a value for evaluating the hydrophilicity of the compound proposed by Griffin, which is a value calculated by the following general formula (2). The HLB value by the Griffin method shows a value within the range of 0 to 20, and the larger the value, the more hydrophilic the compound is.
HLB value = 20 × (mass% of hydrophilic group) = 20 × (sum of formula weight of hydrophilic group / molecular weight of surfactant) (2)

  Specific examples of acetylene glycol surfactants include orphin D-10A, orphin D-10PG, orphin E1004, orphin E1010, orphin E1020, orphin E1030W, orphin PD-001, orphin PD-002W, orphin PD-003, orphin PD-004, olfin PD-201, olfin PD-301, olfin EXP. 4001, Olfin EXP. 4200, Olfin EXP. 4123, Olfin EXP. 4300, Surfynol 82, Surfynol 104 E, Surfynol 104 H, Surfynol 104 A, Surfynol 104 PA, Surfynol 104 PG-50, Surfynol 104 S, Surfynol 420, Surfynol 440, Surfynol 465, Surfynol 485, Surfynol 2502, Dynol 604, Dynol 607, manufactured by Nisshin Chemical Industry Co., Ltd., Acetylenol E13T, Acetylenol EH, Acetylenol EL, Acetylenol E40, Acetylenol E60, Acetylenol E81, Acetylenol E100, Acetylenol 85, manufactured by Kawaken Fine Chemicals Co., Ltd. It is possible to mention and 1 type or 2 types or more can be used preferably. Among the above-mentioned surfactants, olfin E1010 or olfin PD-002W is particularly preferable in consideration of the wettability, the improvement of the slipperiness, and the defoaming effect.

ここで、Ｒ_６、Ｒ_７は炭化水素基を示す。 (Acetylene alcohol surfactant)
The acetylene alcohol surfactant in the present invention has a structure of the following general formula (3).

Here, R ₆ and R _{7 each} represent a hydrocarbon group.

The acetylene alcohol surfactant preferably has an HLB value of 4 to 10, and a value of 5 to 9 in consideration of the wettability and sliding property to the ink cartridge, and the dissolution stability to the ink composition. Is more preferable, and it is particularly preferable to have a value of 6 to 8.
The HLB value is a numerical value determined by the Griffin method.
As a specific example of the acetylene alcohol surfactant, Surfynol 61, Orphine B, (manufactured by Nisshin Chemical Industry Co., Ltd.) can be mentioned, and one or two or more can be preferably used.

The content of the acetylene glycol surfactant or the acetylene alcohol surfactant in the aqueous ink composition of the present invention is preferably 0.005 to 1.5% by mass with respect to the total amount of the ink composition, 0 The content is more preferably 0.1 to 1.0% by mass, and particularly preferably 0.05 to 0.75% by mass.
When the content of the acetylene glycol surfactant or the acetylene alcohol surfactant is within the above numerical range, the mobility of the ink composition in the ink cartridge is further improved, and the ink dischargeability from the pen point during writing is improved. As well as being better, it becomes easy to suppress ink leakage from the pen tip during storage.
Furthermore, when the content is within the above-mentioned numerical range, it is possible to make an ink composition excellent in the blur resistance and the reverse transfer resistance of the handwriting.
The acetylene glycol surfactant and the acetylene alcohol surfactant may be used in combination.
When using the said surfactant together, it is preferable to make the content into the said numerical range.

  The composition of the present invention contains at least water in addition to the coloring agent and the surfactant, but the content is preferably 50 to 95% by mass with respect to the total amount of the ink composition, and 70 to 90%. It is more preferable to use%.

(Others)
In the ink composition of the present invention, as long as the contact angle and the falling angle of the ink composition do not exceed the above-mentioned numerical range, it is possible to add substances other than the above as required. Specifically, preservatives, kaolin, talc, mica, clay, bentonite, calcium carbonate, aluminum hydroxide, sericite, and potassium titanate, polyolefin resin, acrylic resin, nylon resin, silicone resin, urethane Resin particles consisting of resin and fluorine resin, acrylic resin, urethane resin, styrene-butadiene resin, alkyd resin, sulfonamide resin, maleic acid resin, polyvinyl acetate resin, ethylene vinyl acetate resin, vinyl chloride vinyl acetate resin, styrene Copolymers of styrene and maleic acid ester, styrene-acrylonitrile resin, cyanate-modified polyalkylene glycol, ester gum, xylene resin, urea resin, urea aldehyde resin, phenol resin, alkyl phenol resin, terpene phenol resin, Fixing agents such as gin resins and their hydrogenated compounds, rosin phenol resins, polyvinyl alkyl ethers, polyamide resins, polyolefin resins, nylon resins, polyester resins, cyclohexanone resins, etc., pH adjusters, antifoaming agents, shear thinning agents Anticorrosion agents such as viscosity modifiers, benzotriazole, tolyltriazole, dicyclohexyl ammonium nitrite, diisopropyl ammonium nitrite, and saponin, various surfactants such as urea, anion, cationic, nonionic, amphoteric, polyvinyl alcohol, Pigment dispersant consisting of water soluble resin such as polyvinyl pyrrolidone, reduced or non-reduced starch hydrolyzate, disaccharide such as trehalose, oligosaccharide, sucrose, cyclodextrin, glucose, dextrin, sorbite, mannitol Mention may be made bets, and a wetting agent such as sodium pyrophosphate.

(Ink composition)
In the ink composition of the present invention, it is important to set the contact angle and sliding angle to polyethylene and polymethylpentene within a predetermined numerical range in consideration of wettability and slipperiness to the ink cartridge. Here, the contact angle is the angle between the liquid surface and the solid surface where the free surface of the stationary liquid is in contact with the solid wall, and is a numerical value as an index of the wettability of the liquid to the solid. Is the angle of the solid relative to the ground when the liquid begins to slide on the solid surface when the solid with liquid deposited on the surface is inclined to the ground, and the slipperiness of the liquid on the solid surface It is a numerical value that serves as an indicator.
The specific contact angle and sliding angle in the ink composition of the present invention are such that the contact angle is 40 to 100 ° with respect to polyethylene and the sliding angle is 10 to 65 °, and for polymethylpentene The contact angle may be 45 to 90 °, and the falling angle may be 10 to 45 °. An ink composition having a contact angle in the above numerical range has good wettability, and an ink composition having a sliding angle in the above numerical range has good slip properties. When used in an ink cartridge of a writing tool to be described later, the ink composition can smoothly move in the ink cartridge, and when used in a writing tool, the ink dischargeability is improved.

In consideration of the wettability and slipperiness of the ink composition to the ink cartridge, the preferable numerical range of the contact angle is 45 to 90 ° for polyethylene and 45 for polymethylpentene. The preferred contact angle is from 50 to 85 for polyethylene and from 55 to 80 for polymethylpentene.
The preferred numerical range of the sliding angle is 15 to 55 ° for polyethylene, 15 to 40 ° for polymethylpentene, and the more preferred numerical range is 20 for polyethylene. 50 °, and 25-35 ° for polymethylpentene.
The measurement of the contact angle and the falling angle of the composition in the present invention is performed using a contact angle meter (CA-A, manufactured by Kyowa Interface Science Co., Ltd.).
In addition, about measurement operation of a contact angle, it carries out based on the liquid measurement measurement operation described in the instruction manual of the said contact angle meter, and, about measurement operation of a fall angle, to the fall method measurement operation of the said instruction manual. Do based on.

The surface tension of the ink composition of the present invention is preferably 30 to 60 mN / m, and more preferably 40 to 50 mN / m.
The ink composition having such surface tension improves not only the wettability with respect to the ink guiding core but also the ink dischargeability from the pen point can be made better, but also the writing of the writing It is possible to form a good handwriting whose bleeding and strikethrough are suppressed.
The surface tension is measured by a vertical plate method using a surface tension measuring instrument manufactured by Kyowa Interface Science Co., Ltd. and a platinum plate in a 20 ° C. environment.

  The viscosity of the ink composition of the present invention is preferably 1 to 10 mPa · s. A more preferable numerical range is 1 to 5 mPa · s, and it is particularly preferable to be 1 to 2 mPa · s. When the viscosity of the ink composition is within the above numerical range, the movement of the ink composition in the ink cartridge becomes smoother, the ink dischargeability from the pen point becomes better, and it is easy to form a handwriting excellent in color development. Become. The viscosity of the composition is measured at 20 ° C. using an EL type rotational viscometer (RE-80 L, cone type rotor: standard type (1 ° 34 ′ × R24), manufactured by Toki Sangyo Co., Ltd.) be able to.

  The composition of the present invention preferably has a pH value of 6 to 11 and more preferably 8 to 10, in consideration of the stability of the ink composition.

  The aqueous ink composition according to the present invention can be produced by any method known in the art. Specifically, the respective components can be compounded in necessary amounts, and mixed by various stirring machines such as propeller stirring, homodisper or homomixer, various dispersing machines such as bead mill, or the like.

(Writing instrument)
In the ink composition, a pen point, a detachable ink cartridge, and a plurality of disk bodies are arranged in parallel with a comb-like groove at intervals, and a slit-like ink guide groove longitudinally penetrating the disk body; A direct-liquid writing instrument comprising a pen core having an air-permeable groove wider than the groove and having an ink-inductive core for guiding ink from the ink storage portion to the pen tip at the axial center, more specifically It is used by filling in the ink reservoir of a fountain pen, marking pen and ballpoint pen.

  Among the tips, a fiber tip, a felt tip, a plastic tip, a brush and the like can be applied as a marking pen tip, and a metal pipe is used as a ballpoint tip. A tip formed by holding the ball in a ball holding portion pressed and deformed in the vicinity of the tip of the tip from the outer surface, and a ball held in a ball holding portion formed by cutting a metal material with a drill or the like A chip, a chip in which a resin ball receiving seat is provided inside a metal or plastic chip, or a chip in which a ball held by the chip is urged forward by a spring body can be used. As the ball, cemented carbide, stainless steel, ruby, ceramic, resin, rubber and the like can be applied, and balls having a diameter of 0.15 mm to 2.0 mm are suitably used.

  Moreover, as a tip (pen body) of a fountain pen form, a metal plate such as a stainless steel plate or a gold alloy plate can be cut into a tapered shape and bent or curved, or a resin molded into a pen tip shape, etc. . The pen body may be provided with a slit at the center or with a ball at its tip.

  The ink storage portion is not particularly limited as long as the ink storage portion is disposed behind the pen tip via a pen core and can detachably store an ink storage container called an ink cartridge from the writing instrument main body.

  As the ink cartridge, one that doubles as a cylinder constituting a writing tool by being connected to the writing tool main body, and one that covers and protects the shaft cylinder (rear shaft) after being connected to the writing tool main body can be applied. These cartridges may be pre-filled with ink prior to connecting the writing tool, and after connecting to the writing tool in the non-filled state, it requires an operation to suck the ink from the pen point and fill the ink , May be called a so-called converter.

The ink cartridge used in the present invention is not particularly limited as long as it has a material and a structure that allows the ink composition to move smoothly in the ink cartridge.
Specific materials include polyolefin resins such as polyethylene, polypropylene and polymethylpentene, polycarbonate, polystyrene, acrylic resin, polyvinyl chloride, urethane resin, ABS resin, synthetic resin such as AS resin, aluminum, copper, iron, nickel And metals such as titanium, natural rubber, diene rubber, styrene butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, butadiene rubber, acrylonitrile butadiene rubber, etc., alumina, zirconia, silicon nitride, silicon carbide, etc. Glass such as ceramic, soda glass, potassium glass, lead glass, quartz glass, hybrid glass and the like can be mentioned.
Among the above, the preferable material for the ink cartridge is a synthetic resin, a polyolefin resin is more preferable, and polyethylene or polymethylpentene is particularly preferable.
When polyethylene or polymethylpentene is used as the material, it is possible to obtain an ink cartridge which is excellent in shape stability, light in weight and excellent in strength while making the wettability and slipperiness of the ink composition of the present invention good.

The ink cartridge is a bottomed cylindrical body having a circular cross section orthogonal to the longitudinal direction, and has a length of 40 to 80 mm and a diameter of 2 to 8 mm in the longitudinal direction. The structure which has as a size is mentioned. The bottomed cylindrical body preferably has a length of 45 to 70 mm in the longitudinal direction and a diameter of 2.5 to 7 mm as inner dimensions.
The term “cylindrical body” refers to a hollow elongated rod-like body, but in the ink cartridge used in the present invention, the outer surface and the inner surface of the tubular body are tapered when the inner size is within the above numerical range. It may have a level difference.
The ink cartridge of the present invention is important because the above-described materials and structures allow the ink composition to move smoothly in the ink cartridge.

  As the ink induction core, any synthetic resin that can be injection molded into a comb-groove-like structure with many disks can be used, such as general-purpose polycarbonate, polypropylene, polyethylene, acrylonitrile-butadiene-styrene copolymer, etc. In particular, an acrylonitrile-butadiene-styrene copolymer is preferable from the viewpoints of high moldability and easy obtaining of pen core performance.

  With the above-described ink composition, the writing instrument provided with the above mechanism can smoothly move the ink composition through the ink cartridge while suppressing ink leakage from the pen tip during storage. At the time of writing, good ink dischargeability is exhibited, and it becomes possible to form a handwriting excellent in color development.

  Although the Example of the water-based ink composition of this invention, the ink cartridge using it, and a writing instrument is shown below, this invention is not limited to this.

Example 1
The aqueous ink composition for a writing instrument was obtained by stirring and mixing at room temperature for 1 hour with the following raw materials and compounding amounts. The contact angle and fall angle of the aqueous ink composition obtained were measured using a contact angle meter (trade name: CA-A, manufactured by Kyowa Interface Science Co., Ltd.). Yes, it was 68 ° for polymethylpentene, the sliding angle was 39 ° for polyethylene and 23 ° for polymethylpentene.
In addition, the viscosity of the ink composition was measured using an EL-type rotational viscometer (RE-80L, cone-type rotor: standard type (1.degree. 34'.times. R24), manufactured by Toki Sangyo Co., Ltd.). The viscosity at a rotational speed of 100 rpm was 1.2 mPa · s.
Furthermore, as a result of measuring the pH value of the aqueous ink composition at 20 ° C. using a pH meter (trade name: pH meter D-51, manufactured by HORIBA, Ltd.), the pH value was 9.6.
In addition, the surface tension of the obtained aqueous ink composition was measured by a surface tension measuring instrument (in a 20 ° C. environment, vertical plate method, trade name: surface tension meter DY-300, manufactured by Kyowa Interface Science Co., Ltd.), It was 39.3 mN / m.
・ Colorant water black 191-L 10% by mass
(Dye: made by Orient Chemical Industry Co., Ltd.)
・ Acetylene glycol surfactant 0.1 mass%
(Brand name: Olfin E1010, HLB value: 13.3, manufactured by Nisshin Chemical Industry Co., Ltd.)
・ Triethanolamine 0.3% by mass
-Preservative Benzoisothiazolin-3-one 0.3% by mass
(Lonza Japan Co., Ltd., trade name: Proxel XL-2)
-Ion-exchanged water 89.3% by mass

(Examples 2 to 7, Comparative Examples 1 to 6)
The ink compositions of Examples 2 to 7 and Comparative Examples 1 to 6 were obtained by changing the types and addition amounts of the components to be blended as shown in Tables 1 to 2 with respect to Example 1.
The details of the materials used in the above examples are as follows.
Colorant (1) Water Black 191-L (Dye, made by Orient Chemical Industry Co., Ltd.)
・ Colorant (2) Phloxine (dye, manufactured by Hodogaya Chemical Industry Co., Ltd.)
Colorant (3) Brilliant Blue FCF (dye, manufactured by Hodogaya Chemical Industry Co., Ltd.)
Surfactant (1) Acetylene glycol surfactant (trade name: Olfin E1010, HLB value 13.3, manufactured by Nisshin Chemical Industry Co., Ltd.)
Surfactant (2) Acetylene glycol surfactant (trade name: Olfin PD-002W, HLB value 9 to 10, manufactured by Nisshin Chemical Industry Co., Ltd.)
Surfactant (3) Acetylene glycol surfactant (trade name: Surfynol 485, HLB value 17, manufactured by Nisshin Chemical Industry Co., Ltd.)
Surfactant (4) Acetylene glycol surfactant (trade name: Olfin E1020, HLB value 15 to 16, manufactured by Nisshin Chemical Industry Co., Ltd.)
Surfactant (5) Acetylene glycol surfactant (trade name: Olfin EXP. 4300, HLB value 10 to 13, manufactured by Nisshin Chemical Industry Co., Ltd.)
Surfactant (6) Acetylene glycol surfactant (trade name: Acetylenol E60, HLB value 11 to 12, manufactured by Kawaken Fine Chemical Co., Ltd.)
Surfactant (7) Acetylene alcohol surfactant (trade name: Olfin B, manufactured by Nisshin Chemical Industry Co., Ltd.)
Surfactant (8) Phosphate ester surfactant (trade name: Plysurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
Surfactant (9) Silicone surfactant (trade name: TSF-4440, manufactured by Momentive Performance Materials Japan Co., Ltd.)
Surfactant (10) Dodecyl benzene sulfonate (trade name: Neoperex No. 6 F powder, manufactured by Kao Corporation)
-Triethanolamine-Preservative Benzoisothiazolin-3-one (trade name: Proxel XL-2, manufactured by Lonza Japan Co., Ltd.)
・ Ion exchange water

The prepared water-based ink composition was evaluated as follows. The obtained results were as described in Tables 1 to 3.
Moreover, the following were used for the ink cartridge and writing instrument used by evaluation test.
Ink cartridge (1): Bottomed cylindrical container used for polyethylene cartridge (manufactured by Pilot Corporation, trade name: IRF-5S), inner size: length 57.3 mm, diameter, minimum portion 2.5 mm, maximum Part 7.5 mm)
Ink cartridge (2): Converter made of polymethylpentene (a cylindrical container with a bottom, made by Pilot Corporation, trade name: CON-70, internal size: length 49 mm, diameter, minimum 5 mm, maximum 6.4 mm)
Writing instrument: Fountain pen (trade name: Kakuno, manufactured by Pilot Corporation)

(Evaluation of ink transferability to polyethylene ink cartridge)
The following procedure was followed.
1. 0.9 ml of the ink composition is injected into a polyethylene ink cartridge, and the ink inlet of the ink cartridge is plugged, and then the ink cartridge inlet is placed horizontally and left at 50 ° C. for 72 hours.
2. After the ink cartridge is returned to room temperature, 0.6 ml of ink is drawn with the ink cartridge inlet facing upward, and the ink inlet is plugged and left for 24 hours.
3. Visually observe the movement of the ink when turning the ink cartridge upside down.
Good: All of the ink composition flowed smoothly within 10 seconds.
X: The ink remained at the bottom of the cartridge and did not flow down.
(Evaluation of ink transferability for polymethylpentene ink cartridge)
The following procedure was followed.
1. Inject 0.7 ml of the ink composition into a polymethylpentene converter, and mount the converter on a fountain pen with the pen tip facing upward.
2. Visually observe the movement of the ink when the pen is inverted so that the angle of the pen tip to the ground is 60 °.
Good: All of the ink composition flowed smoothly within 10 seconds.
X: The ink remained at the bottom of the cartridge and did not flow down.

(Evaluation of handwriting coloration)
The ink cartridge used in the evaluation of the ink transferability was attached to the writing instrument, writing was performed, and the coloring property of the handwriting at that time was visually observed. In addition, the writing paper based on JISP3201A was used as a writing test paper.
○: There is no blur, and the handwriting is good.
X: There is faintness, handwriting recognition is difficult, and there is a practical concern.

(Evaluation of ink leakage)
The evaluation was performed according to the following procedure.
1. Inject 0.9 ml of the ink composition into a polyethylene cartridge.
2. Attach the cartridge to a fountain pen, fit the cap, and leave it at 0 ° C for 1 hour or more.
3. The cap of the fountain pen was removed, and leakage of the ink composition from the pen tip was visually observed when left at 40 ° C. for 1 hour.
○: Ink leakage from the pen point was not confirmed.
X: Ink leaked from the pen point.

Claims (7)

  An aqueous ink composition incorporated in a writing instrument having a removable ink cartridge, comprising at least water, a colorant, and an acetylene glycol surfactant or an acetylene alcohol surfactant, the aqueous ink for polyethylene described above The contact angle of the composition is 40 to 100 °, the falling angle is 10 to 65 °, and the contact angle of the aqueous ink composition to polymethylpentene is 45 to 90 °, and the falling angle is 10 to 10 °. The aqueous ink composition for writing instruments which is 45 degrees.   An ink cartridge comprising the water-based ink composition for a writing instrument according to claim 1.   The ink cartridge according to claim 2, wherein the material is polyethylene or polymethylpentene.   The bottomed cylindrical body having an orthogonal cross section orthogonal to the longitudinal direction having a circular shape, and having a length of 40 to 80 mm in the longitudinal direction and a diameter of 2 to 8 mm as inner dimensions. The ink cartridge according to any one of the above.   A writing instrument comprising the ink cartridge according to claim 4 accommodated therein.   In the writing instrument, a pen point, a detachable ink cartridge, and a number of disc bodies are arranged in parallel with a comb-like groove spaced from each other, and a slit-like ink guiding groove longitudinally penetrating the disc body The pen according to claim 5, further comprising: a pen core provided with a wide-width venting groove and having an ink guiding core for guiding the ink from the ink storage portion to the pen tip in the axial center. Writing instrument.   The writing instrument according to claim 6, wherein the direct solution writing instrument is a fountain pen.