JP2019131683A - Aqueous ink composition for writing instruments, and writing instrument including the same - Google Patents

Abstract

To provide an aqueous ink composition for writing instruments that sufficiently inhibits the ink leakage phenomenon while ensuring excellent ink movement in an ink storage body, and shows excellent writing properties and excellent handwriting, and a writing instrument including the same.SOLUTION: The present invention provides an aqueous ink composition for writing instruments containing water, a colorant, polyoxyethylene tribenzyl phenyl ether, and alkanolamine, and a writing instrument including the same.SELECTED DRAWING: None

Description

  The present invention relates to a water-based ink composition for a writing instrument, and a writing instrument using the same.

The writing instrument has a structure in which a pen nib is attached to the end of the shaft cylinder through an appropriate ink flow rate adjusting body for adjusting the ink flow rate, and an ink storage body for containing the ink composition is provided in the shaft cylinder. There is. In order to write, this type of writing instrument is used when the ink composition contained in the ink reservoir passes along the inner wall of the ink reservoir when the pen nib is in the pen-up or horizontal position to the pen-down state. Writing down is possible by flowing down. (The flow of the ink composition is called ink mobility.)
However, many parts of writing instruments, including ink reservoirs, are often made of resin, and since they are hydrophobic, even if the pen tip faces downward, the wettability of the ink composition to the parts is low. Insufficient, the ink composition does not flow down, stays in the original position, the ink composition is not supplied to the pen tip, and there is a problem that the handwriting is faded or, at worst, cannot be written.

  In order to solve the above problems, it is generally considered to lower the surface tension of the ink composition. However, since the surface tension plays an important role as a drag against the movement of the ink composition due to gravity, atmospheric pressure, and impact, the surface tension of the ink composition was lowered to improve the ink mobility in the ink reservoir. In some cases, the drag force is insufficient, and even when not writing, when the pen tip is turned downward, the ink may be ejected by a slight impact or vibration, or the ink may overflow due to changes in atmospheric pressure. In some cases, new problems such as ink leakage may occur.

Therefore, an aqueous ink composition has been proposed in which an additive such as maltosyl cyclodextrin is added to improve the ink mobility in the ink reservoir without lowering the surface tension. (Patent Document 1)
However, when the maltosyl cyclodextrin and the like are added to the ink composition to such an extent that good ink mobility can be obtained, the ink viscosity is increased, ink followability is lowered, and good handwriting is hardly obtained. In addition, since the solubility in water is low, there are problems such as affecting the anti-drying performance of the nib.

  Thus, in the conventional ink composition, in order to improve the ink mobility in the ink storage body, if the surface tension is lowered to improve the wettability to the ink storage body, the drag is insufficient and the ink cannot be retained. Ink leakage will occur. On the other hand, if the surface tension of the ink composition is increased to some extent in order to suppress ink leakage, ink mobility in the ink reservoir cannot be obtained sufficiently. In addition, when trying to solve the above problems regardless of the adjustment of the surface tension of the ink composition, problems arise in the writing properties and the handwriting obtained, such as the handwriting being blurred or being unable to write better than the first writing, The performance as a composition was not fully satisfied.

  Accordingly, there is a need for a water-based ink composition that simultaneously solves the two problems of improving the ink mobility in the ink storage body and suppressing the leakage of the ink, has excellent writing properties, and provides good handwriting. In particular, in a writing instrument having a structure in which a pen tip is attached to an end portion of a shaft cylinder through an appropriate ink flow rate adjusting body for adjusting the ink flow rate, and an ink storage body for containing an ink composition is provided in the shaft cylinder. With a low viscosity ink composition that can be suitably used, it is more difficult to solve the above-mentioned problems, which has been a major problem.

Japanese Patent Laid-Open No. 5-140498

  The present invention provides a water-based ink composition for a writing instrument having excellent leakage resistance and excellent ink transfer performance in an ink storage body, and a writing instrument using the same.

  The water-based ink composition for writing instruments according to the present invention is a water-based ink composition for writing instruments comprising water, a colorant, polyoxyethylene tribenzylphenyl ether, and alkanolamine.

  The writing instrument according to the present invention is characterized in that it contains the water-based ink composition for a writing instrument.

  According to the present invention, while sufficiently suppressing the phenomenon of ink leakage from the nib, it is excellent in leakage resistance and ink transfer performance in the ink storage, such as excellent ink mobility in the ink storage. It is possible to provide a water-based ink composition for a writing instrument that can provide good writing properties and good handwriting, and a writing instrument using the same.

  Hereinafter, embodiments of the present invention will be described in detail. In the present specification, “part”, “%”, “ratio” and the like indicating the composition are based on mass unless otherwise specified, and the content is a constituent component based on the mass of the ink composition. % By mass.

A water-based ink composition for a writing instrument according to the present invention (hereinafter, sometimes referred to as an ink composition) comprises water, a colorant, polyoxyethylene tribenzylphenyl ether, and an alkanolamine. To do.
The ink composition of the present invention in which polyoxyethylene tribenzylphenyl ether and alkanolamine are used in combination can sufficiently and immediately wet the wall surface in a resin-made ink reservoir that is hydrophobic. For this reason, the ink composition in the ink reservoir does not stay in its original position, but immediately flows down the wall surface when the pen tip is in the pen tip downward state for writing. It becomes possible to have excellent ink transfer performance, the ink composition is sufficiently supplied to the tip of the pen, the handwriting is not faded, and furthermore, it is not possible to write, leaving a good handwriting be able to.
In particular, the ink composition of the present invention is good even when the wall surface in the ink storage body is not pre-wetted with the ink composition, such as after being left for a long time in the pen tip upward state, and the ink flow is severe. Has ink transfer performance. In addition, the ink composition of the present invention can appropriately maintain not only the ink reservoir but also the wettability with respect to the resin ink flow regulator. For this reason, the function of the ink flow rate regulator can be sufficiently obtained, and the ink ejection from the pen tip can be maintained well. In particular, when the ink composition of the present invention is used for a writing instrument having a comb-like ink retaining member on the ink flow rate adjusting body, the wettability with respect to the comb-like ink retaining member is appropriately maintained. Excess ink pushed out of the ink reservoir due to the change can smoothly flow into the comb-like ink retaining member, and ink leakage can be effectively suppressed.
Furthermore, the ink composition of the present invention can obtain the effect of the excellent ink transfer performance in the ink storage body and the excellent leakage resistance performance over a long period of time.
The reason for this is not clear, but polyoxyethylene tribenzylphenyl ether has the effect of improving the wettability of the ink composition to the resin material, but when used in combination with alkanolamine, the above effect is sufficiently and efficient. I think that it will be able to get well.
In addition, since the surface tension of the ink composition of the present invention does not extremely decrease, the ink does not jump out of the pen tip with a slight impact or vibration even when not writing, and has excellent leakage resistance performance. Become. Furthermore, it is possible to prevent penetrating from penetrating or see-through by increasing the permeability to the paper surface.
The ink composition of the present invention using polyoxyethylene tribenzylphenyl ether and alkanolamine in combination has excellent dry-up resistance. For this reason, the ink composition of the present invention has good writing performance while being excellent in ink transfer performance and leakage resistance.
Hereinafter, each component used will be described in detail.

<Polyoxyethylene tribenzyl phenyl ether>
The ink composition of the present invention comprises polyoxyethylene tribenzyl phenyl ether. Polyoxyethylene tribenzylphenyl ether can be represented by the following formula (1).

By including polyoxyethylene tribenzylphenyl ether in the ink composition, the wettability to the resin material can be improved without greatly reducing the surface tension of the ink composition. For this reason, it is possible to properly maintain the wettability with respect to the ink storage body and the ink flow rate adjusting body, and to provide the ink composition with contradictory performance such as excellent ink mobility in the ink storage body and excellent leakage resistance. it can.
In addition, polyoxyethylene tribenzyl phenyl ether can bring about the above effects in a very small amount. For this reason, the ink composition performance and physical properties such as ink discoloration are not adversely affected, and excellent ink mobility and excellent leakage resistance can be provided.
The content of polyoxyethylene tribenzylphenyl ether is preferably 2% by mass or less based on the total mass of the ink composition. In the present invention, it is particularly preferably less than 1% by mass based on the total mass of the ink composition. If the content of polyoxyethylene tribenzylphenyl ether is less than 1% by mass, it is easy to maintain a good balance between ink transfer performance and leak-proof performance in the ink reservoir, and the pen tip when not writing Even in the downward state, the ink tends to be effectively prevented from jumping out of the pen tip with a slight impact or vibration. In addition, the suppression of handwriting bleeding and back-through can be improved. Considering the improvement of the above effect, it is more preferably 0.001 to 0.5% by mass, further preferably 0.01 to 0.5% by mass, and 0.01 to 0.1% by mass. It is particularly preferred.

Moreover, when the improvement of the ink mobility in an ink storage body and the improvement of leak-proof performance are considered, it is preferable that the HLB value of polyoxyethylene tribenzyl phenyl ether is 6-20, and it is 8-18. More preferably, it is 10-16.
Here, the HLB value means a hydrophilic / lipophilic balance, which is calculated by the Griffin method.

  In addition, the polyoxyethylene tribenzylphenyl ether has an average value of the number of added polyoxyethylene (value of n in the formula (1)) is preferably n = 3 to 100, and n = 5 to 50. More preferably, n = 5 to 30 is more preferable, and n = 10 to 30 is particularly preferable. If the average value of the number of moles of polyoxyethylene added to polyoxyethylene tribenzylphenyl ether is within the above numerical range, good solubility in water can be obtained, and further, excellent in an ink composition together with alkanolamine. The solution stability can be shown, and the effect of polyoxyethylene tribenzylphenyl ether can be obtained immediately and in the long term. The number of n is not a single value but may be a mixture having a certain width.

  Specific examples of polyoxyethylene tribenzyl phenyl ether include Emulgen B-66 (manufactured by Kao Corporation), pegnol 005 (manufactured by Toho Chemical Co., Ltd.), and the like.

<Alkanolamine>
The ink composition of the present invention comprises alkanolamine.
Alkanolamine has been conventionally used as a pH adjuster, but in the present invention, it improves the wettability with respect to the resin material efficiently, provides excellent ink mobility in the ink reservoir, and excellent leakage resistance. It can be given to the composition.
The reason for this is not clear, but is considered as follows. As described above, polyoxyethylene tribenzylphenyl ether has an effect of improving the wettability with respect to the resin material, but by using together with alkanolamine, the dissolution stability of polyoxyethylene tribenzylphenyl ether is sufficiently maintained, It is thought that the improvement of wettability with respect to the resin material can be obtained efficiently, immediately, and in the long term.
Therefore, the ink composition of the present invention in which alkanolamine and polyoxyethylene tribenzylphenyl ether are used in combination can immediately wet the wall surface and the ink flow rate regulator in the ink reservoir in the long term. For this reason, it has excellent ink mobility in the ink storage body and excellent leakage resistance.

  The alkanolamine is a compound having a hydroxy group and an amino group in the alkane skeleton. In the present invention, it is preferable to use an alkanolamine represented by the following formula (2).

式（２）中、Ｒ_１ はエチレン基、トリメチレン基又はプロピレン基を示し、Ｒ_２ 及びＲ_３ はそれぞれ独立に水素原子、メチル基、エチル基又は −Ｒ_１−ＯＨ 基を示す。

In the formula (2), R ₁ represents an ethylene group, trimethylene group or propylene group, and R ₂ and R ₃ each independently represent a hydrogen atom, a methyl group, an ethyl group or a —R ₁ —OH group.

Specific examples of such alkanolamines include, for example, methylethanolamine, monoisopropanolamine, diethylethanolamine, monoethanolamine, propanolamine, methyldiethanolamine, diethanolamine, triethanolamine and the like.
In the present invention, considering the compatibility with polyoxyethylene tribenzylphenyl ether, further improving the wettability of the resin material, and considering the temporal stability of the ink composition, among the above alkanolamines, a weak base It is preferable to use triethanolamine, which improves the wettability of the ink composition to the ink reservoir and the ink flow controller, and provides excellent ink mobility and excellent leakage resistance in the ink reservoir. Can be obtained stably over time.
Triethanolamine is excellent in hygroscopicity, and therefore tends to improve the dry-up resistance of the ink composition. For this reason, in the present invention, the use of polyoxyethylene tribenzylphenyl ether and triethanolamine tends to improve ink mobility and leakage resistance in the ink reservoir and further improve writing performance.

  The content of alkanolamine in the ink composition is preferably 0.1 to 10% by mass based on the total mass of the ink composition. If the content of the alkanolamine is within the above numerical range, the effect of polyoxyethylene tribenzylphenyl ether can be efficiently brought to the ink composition in the long term, while maintaining excellent leakage resistance performance, The ink transfer performance in the storage can be further improved. Furthermore, in view of improvement in dry-up resistance and color development of handwriting, the content is more preferably 0.1 to 5% by mass, and further preferably 0.5 to 3% by mass.

<Colorant>
The coloring agent that can be used in the present invention includes any dye or pigment, and is not particularly limited.

The dye is not particularly limited, and examples thereof include acid dyes, basic dyes, direct dyes, disperse dyes, oil-soluble dyes, reactive dyes, metal-containing dyes, food dyes, and various salt-forming dyes. Is mentioned.
These may be used alone, or two or more dyes may be used.

  Specifically, examples of the acid dye include C.I. I. Acid Red 18, C.I. I. Acid Red 51, C.I. I. Acid Red 52, C.I. I. Acid Red 87, C.I. I. Acid Red 92, C.I. I. Acid Red 289, C.I. I. Acid Orange 10, C.I. I. Acid Yellow 3, C.I. I. Acid Yellow 7, C.I. I. Acid Yellow 23, C.I. I. Acid Yellow 42, C.I. I. Acid Green 3, C.I. I. Acid Green 16, C.I. I. Acid Blue 1, C.I. I. Acid Blue 9, C.I. I. Acid Blue 22, C.I. I. Acid Blue 90, C.I. I. Acid Blue 239, C.I. I. Acid Blue 248, C.I. I. Acid Violet 15, C.I. I. Acid Violet 49, C.I. I. Acid Black 1, C.I. I. Acid Black 2 and basic dyes include C.I. I. Basic Orange 2, C.I. I. Basic Orange 14, C.I. I. Basic Green 4, C.I. I. Basic Blue 9, C.I. I. Basic Blue 26, C.I. I. Basic Violet 1, C.I. I. Basic Violet 3, C.I. I. Basic violet 10 includes C.I. I. Direct Red 28, C.I. I. Direct Yellow 44, C.I. I. Direct Blue 86, C.I. I. Direct Blue 87, C.I. I. Direct violet 51, C.I. I. Direct black 19 and disperse dyes include I. Disperse Yellow 82, C.I. I. Disperse Yellow 3, C.I. I. Disperse Yellow 54, C.I. I. Disper thread 191, C.I. I. Disperse thread 60, C.I. I. Disperse violet 57 and food coloring include C.I. I. Food Yellow 3, C.I. I. Food black 2 etc. are mentioned.

  The pigment that can be used in the present invention is not particularly limited. For example, an inorganic pigment, an organic pigment, a processed pigment, etc. are mentioned. Specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium, triphenylmethane, perinone, perylene, gioxazine, Examples thereof include aluminum pigments, pearl pigments, fluorescent pigments, phosphorescent pigments, and complementary color pigments. In addition, a colored resin particle obtained by coloring resin particles with a dye or the like, or a colored body in which a coloring material is dispersed in a medium is encapsulated in a shell made of a resin wall film forming substance by a known microencapsulation method or the like. You may use the solid capsule microcapsule pigment.

  In the ink composition of the present invention in which polyoxyethylene tribenzylphenyl ether and alkanolamine are used in combination, it is preferable to use a dye. Among them, it is preferable to use an acid dye or a basic dye, and it is particularly preferable to use an acid dye. . In addition, when xanthene and azo dyes are used, it is easy to improve the wettability of polyoxyethylene tribenzylphenyl ether with respect to the resin material, and ink mobility and leakage resistance in the ink storage This is particularly effective.

As the colorant, the above pigments and dyes may be used alone or in combination of two or more.
The content of the colorant in the ink composition is preferably 0.1 to 10% by mass based on the total mass of the ink composition. When the content of the colorant is within the above numerical range, it is possible to prevent a decrease in ink discharge properties and obtain good handwriting excellent in color development.

<Water>
There is no restriction | limiting in particular as water, For example, tap water, ion-exchange water, ultrafiltration water, or distilled water can be used.

<Other additives>
The ink composition according to the present invention can contain any additive as required. The additive that can be used is described as follows.

The ink composition of the present invention preferably further uses a chelating agent for sequestering the metal present in the ink composition.
The ink composition of the present invention may be replenished and used by a user in an ink reservoir, and the ink may be stored in a glass ink container such as a glass bottle.
Glass bottles are easy to mold and easily available at a low cost, and in addition, it is easy to obtain the desired strength. On the other hand, when using inexpensive and versatile soda-lime glass, etc., the ink composition can be stored for a long time. If so, there is a high possibility that the alkali component in the glass is eluted in the ink composition, and the eluted alkali component and the component of the ink composition may react to form a precipitate.
For this reason, it is effective to further use a chelating agent in the ink composition of the present invention. Even when the chelating agent is contained in a glass ink container, it supplements the eluted alkaline component, and the alkaline component is the ink composition. Prevents water-insoluble precipitates from reacting with the components in the ink, and prevents ink deposits from being blocked by the generated precipitates, causing handwriting to become blurred or unwritable. Can do.

Examples of the chelating agent include ethylenediaminetetraacetic acid (EDTA) such as aminocarboxylic acid, hydroxyethylenediaminetriacetic acid (HEDTA), glycol etherdiaminetetraacetic acid (GEDTA), nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), Examples include dihydroxyethylglycine (DHEG), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), and alkali metal salts, ammonium salts, or amine salts thereof.
Considering that the alkali component can be sufficiently supplemented, and that the physical properties of the ink composition before and after the compounding of the chelating agent tend not to be greatly affected, it is preferable to use an aminocarboxylic acid among the chelating agents. Of these, ethylenediaminetetraacetic acid (EDTA) and salts thereof are preferably used.
In addition, the ink composition of the present invention further includes ethylenediaminetetraacetic acid (EDTA) and a salt thereof, and thus tends to further improve ink mobility and leakage resistance in the ink reservoir. For this reason, it is effective to use polyoxyethylene tribenzylphenyl ether, alkanolamine, and ethylenediaminetetraacetic acid (EDTA) or a salt thereof in combination.

The content of the chelating agent in the ink composition is preferably 0.01 to 1% by mass based on the total mass of the ink composition. If it is 1 mass% or less, the ink composition performance and physical properties such as ink discoloration will not be adversely affected. Moreover, if it is 0.01 mass% or more, the alkali component eluted from glass can be supplemented and generation | occurrence | production of a precipitate can be suppressed. Moreover, if it is in the said numerical range, the ink mobility and the leak-proof performance which were excellent in the ink storage body can be obtained.
Moreover, there exists a tendency for a chelating agent to further improve leak-proof performance by adding appropriate amount. Therefore, when the generation | occurrence | production suppression of precipitation and the further improvement of leak-proof performance are considered, it is more preferable that it is 0.01-0.5 mass%.

  The ink composition of the present invention further contains additives such as water-soluble organic solvents, pH adjusters, rust inhibitors, preservatives, moisturizers, penetrants, and lubricants for the purpose of improving ink physical properties and functions. May be included.

Examples of the water-soluble organic solvent include (i) glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, or glycerin, (ii) methanol, ethanol, 1-propanol, 2-propanol, isopropanol, isobutanol, t Alcohols such as butanol, propargyl alcohol, allyl alcohol, 3-methyl-1-butyn-3-ol, ethylene glycol monomethyl ether acetate and other higher alcohols, and (iii) ethylene glycol monomethyl ether, ethylene glycol mono Examples include glycol ethers such as ethyl ether, 3-methoxybutanol, and 3-methoxy-3-methylbutanol.
Above all, use of diethylene glycol, ethylene glycol, glycerin, etc. that can effectively obtain the effect of polyoxyethylene tribenzyl phenyl ether because it is compatible with polyoxyethylene tribenzyl phenyl ether and can exist stably. Is preferred.
The content of the water-soluble organic solvent in the ink composition is preferably 0.1 to 10% by mass based on the total mass of the ink composition.

  Examples of the pH adjuster include inorganic salts such as ammonia, sodium carbonate, sodium phosphate, sodium hydroxide, and sodium acetate, organic basic compounds, lactic acid, and citric acid. These pH adjusters are used alone or in combination of two kinds. A mixture of the above may be used.

  Examples of the rust inhibitor include benzotriazole and its derivatives, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, sodium thiosulfate, saponin, or dialkylthiourea.

  As preservatives, phenol, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine, 2-pyridinethiol-1- Examples include sodium oxide, 1,2-benzisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and 2-n-octyl-4-isothiazolin-3-one.

  Examples of the humectant include polyhydric alcohol solvents, urea, or sorbit, and N, N, N-trialkylamino acids such as trimethylglycine, triethylglycine, and tripropylglycine.

  Furthermore, various surfactants other than polyoxyethylene tribenzyl phenyl ether may be included. Specific examples include nonionic, anionic and cationic surfactants, surfactants having an acetylene bond in the structure, silicone surfactants, and fluorine surfactants.

The ink composition according to the present invention preferably has an ink viscosity of 50 mPa · s or less, more preferably 10 mPa · s or less, measured using a B-type rotational viscometer at 60 rpm and 20 ° C. Is preferred. If the viscosity of the ink composition is within the above numerical range, the ink ejection properties from the pen tip and the ink mobility within the ink reservoir can be improved.
When the ink composition of the present invention is used for a writing instrument in which a comb-like ink retaining member is arranged as an ink flow rate adjusting body, even when a pressure change occurs, the ink smoothly flows into the ink retaining member, Leakage from the tip can be suppressed. For this reason, the ink composition of the present invention can be suitably used for the writing instrument, but in this case, the ink viscosity is 3 mPa · s or less in consideration of leakage resistance and ink discharge performance from the pen tip. It is preferable that it is 2 mPa · s or less. The viscosity can be measured using a B-type rotational viscometer (model: BLII, rotor: BL adapter, manufactured by Toki Sangyo Co., Ltd.).

Moreover, it is preferable that the surface tension in 20 degreeC of the ink composition of this invention is 30-70 mN / m. If the surface tension of the ink composition is within the above numerical range, the ink mobility in the ink storage body and the leakage resistance performance are improved, but it is easy to suppress blotting and back-through of the handwriting, resulting in excellent handwriting. be able to. Furthermore, considering the suppression of ink jumping out from the pen tip due to impact or vibration during non-writing and the improvement of ink ejection properties from the pen tip, it is more preferably 35 to 60 mN / m, and 40 to 55 mN / m. More preferably, it is m.
The surface tension is determined by measuring by a vertical plate method using a platinum plate with a surface tension measuring instrument manufactured by Kyowa Interface Science Co., Ltd. in a 20 ° C. environment.

  Moreover, it is preferable that it is 6-11, and, as for pH of the ink composition of this invention, it is more preferable that it is 7-10. If the pH of the ink composition is within the above numerical range, each component in the ink composition can exist stably, which is preferable, and prevents corrosion of the metal part of a writing instrument such as a pen tip that comes into contact with the ink composition. be able to. In the present invention, the pH value can be measured at 20 ° C., for example, with an IM-40S type pH meter (manufactured by Toa DKK Corporation).

<Method for producing ink composition>
The ink composition according to the present invention can be produced by any conventionally known method. Specifically, it can be produced by blending the necessary amounts of the above components and mixing them with various agitators such as propeller agitation, homodisper, or homomixer, and various dispersers such as a bead mill.

<Writing instruments>
The ink composition of the present invention can be used for various writing tools such as marking pens and ballpoint pens using fiber chips, felt chips, plastic chips or ballpoint pen tips, and fountain pens using metal writing tips.

  In addition, the ink composition of the present invention can be used for one having a structure in which the ink composition is directly filled, one having an ink reservoir capable of being filled with the ink composition, and the like.

In the ink composition of the present invention, the ink reservoir can be detachably exchanged with the writing instrument body, or an ink reservoir (ink cartridge) that can be removably attached to the writing instrument body, or an ink container such as an ink bottle can be used to transfer ink directly into the ink reservoir. It can be suitably used for a writing instrument provided with an ink reservoir (ink inhaler) having a function capable of inhalation.
Since there is a possibility that the ink reservoir as described above is provided in the shaft cylinder of the writing instrument, there is a high possibility that the inner diameter of the ink reservoir is restricted. Therefore, the ink composition does not flow easily in the ink reservoir, and special consideration is required for ink mobility in the ink reservoir. Since the ink composition of the present invention is excellent in ink mobility in the ink reservoir, it can be suitably used for a writing instrument comprising the ink reservoir as described above.
In particular, when the material of the ink storage body is formed of a resin material, the ink storage body tends to have poor wettability with the ink composition. For this reason, it is necessary to further consider the ink mobility in the ink storage body, but the ink composition of the present invention is excellent in wettability with respect to the resin material, and is therefore suitable for a writing instrument in which the material of the ink storage body is a resin. Can be used. Among them, the ink composition of the present invention can be suitably used for a writing instrument using an olefin resin as a resin material, particularly an ink storage body using a crystalline olefin resin, and obtains excellent ink mobility. be able to.

  In addition, in some ink inhalers that are ink reservoirs, a member (moving piece member) that is movable in the ink inhaler is disposed in order to facilitate the flow of ink to the pen tip side. Since the ink composition of the present invention has good wettability with respect to the moving piece member as described above, the function of the moving piece member can be sufficiently obtained. Therefore, by using the ink composition of the present invention for a writing instrument provided with an ink inhaler in which a moving piece member is arranged, a remarkable effect can be obtained in ink moving performance.

In addition, the writing instrument that can use the ink composition of the present invention includes a cap type provided with a cap that covers the writing tip, and a protrusion and depression that can accommodate the writing tip in a knock type, rotary type, slide type, etc. It may be a formula. In particular, with respect to the pen-shaped writing instrument, countermeasures against ink leakage from the nib are regarded as more important. For this reason, the ink composition of this invention which is excellent in leak-proof performance can be used suitably for a retractable writing instrument.
Moreover, since the ink composition of the present invention tends to be excellent in anti-drying performance, it can be said that the ink composition can be suitably used for a retractable writing instrument.

  Further, the ink supply mechanism of the writing instrument that can be used by the ink composition of the present invention is not particularly limited. For example, (Mechanism 1) includes an ink guide core composed of a fiber bundle as an ink flow rate regulator, A mechanism for supplying the ink composition to the nib by interposing it, (mechanism 2) a mechanism for supplying the ink composition to the nib with a comb-like ink retaining member as an ink flow rate regulator, and (mechanism 3) Examples thereof include a mechanism that includes an ink flow rate adjusting body using a valve mechanism and supplies the ink composition to the writing tip writing tip, and (mechanism 4) a mechanism that directly supplies the ink to the pen tip without the ink flow rate adjusting body.

Above all, in writing instruments equipped with an ink flow control body, it maintains good ink wettability with respect to the ink flow control body and maintains good ink ejection from the pen tip, but it does not bleed or show through. In order to obtain a good handwriting, it is necessary to keep the surface tension of the ink composition within an appropriate range.
The ink composition of the present invention can satisfactorily maintain the wettability with respect to the ink flow rate adjusting body without extremely reducing the surface tension. For this reason, it can use suitably for a writing instrument provided with an ink flow volume adjustment body like the said (mechanism 1), (mechanism 2), and (mechanism 3).
In particular, the ink composition of the present invention tends to improve the anti-leakage performance by allowing excess ink to flow into the comb-shaped ink retaining member. It can be suitably used for a writing instrument provided with a member as an ink flow rate regulator.
Furthermore, since the ink composition of the present invention has a high effect of improving the wettability with respect to the resin material, it can be particularly suitably used for a writing instrument using the resin material for the ink flow rate regulator.

As described above, when a resin material is used for the ink flow control body, the hydrophobicity becomes stronger due to the effect of the resin type and additives such as a mold lubricant used at the time of molding, and the wettability with the ink composition is increased. There may be special considerations. In this case, it is possible to obtain a stable performance of the ink flow rate adjusting body by performing the surface modification of the ink flow rate adjusting body with the surface modifier, thereby improving the leakage resistance performance and improving the ink ejection property. it can. Examples of the surface modifier include a resin and a surfactant. Specifically, a copolymer containing vinyl acetate and an acrylic ester, a surfactant having an acetylene bond, a succinic surfactant, It is preferable to use a surfactant such as a silicone surfactant. The ink flow rate regulator that has been surface-modified with such a surface modifier can exhibit good wettability with respect to water, that is, an aqueous ink composition.
Therefore, the ink composition of the present invention is used in a writing instrument including an ink flow rate regulator that has been subjected to such surface modification, thereby further improving leakage resistance performance and ink ejection properties, thereby providing good handwriting. Can be obtained, and a remarkable effect can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

<Example 1>
In the following raw materials and blending amounts, raw materials other than the colorant were mixed by propeller stirring to obtain a base solution. Thereafter, a colorant was added to the base liquid and mixed by stirring with a propeller to obtain a water-based ink composition for writing instruments. The viscosity of the obtained ink composition was measured with a B-type rotational viscometer (model: BLII, rotor: BL adapter, manufactured by Toki Sangyo Co., Ltd., sample amount 20 ml). Specifically, the viscosity at 20 ° C. and a rotation speed of 60 rpm was 1.5 mPa · s. Further, the surface tension of the obtained ink composition was measured by a surface tension measuring instrument (in a 20 ° C. environment, a platinum plate, a vertical plate method, manufactured by Kyowa Interface Science Co., Ltd.) and found to be 50 mN / m. Furthermore, as a result of measuring the pH of the ink composition at 20 ° C. using an IM-40S type pH meter (manufactured by Toa DKK Co., Ltd.), the pH was 9.4.
・ Polyoxyethylene tribenzyl phenyl ether 0.05% by mass
(HLB value: 13.2)
・ Alkanolamine 1.0% by mass
(Triethanolamine)
-Colorant 1.0% by mass
(C.I. Acid Red 289)
・ Colorant 0.5% by mass
(C.I. Acid Red 52)
・ Colorant 0.5% by mass
(C.I. Acid Yellow 42)
・ Chelating agent 0.05% by mass
(Ethylenediaminetetraacetic acid trisodium salt)
・ Water-soluble organic solvent 2.0% by mass
(Diethylene glycol)
-Preservative 0.2% by mass
(1,2-Benzisothiazolin-3-one)
・ Water balance

<Example 2 to Example 6, Comparative Example 1 to Comparative Example 3>
The ink compositions of Examples 2 to 6 and Comparative Examples 1 to 3 were changed with respect to Example 1 by changing the types and addition amounts of the components to be blended as shown in Tables 1 and 2. Obtained.

<Preparation of test writing instrument>
The ink compositions of Examples 1 to 6 and Comparative Examples 1 to 3 were placed on a resin ink inhaler (Pilot Corporation, CON-70, ink capacity 1.1 ml) and the ink inhaler opening upward In this state, 0.7 ml was injected so that the moving piece member was completely immersed in the ink composition. This ink inhaler is a knock type with a fountain pen-shaped pen tip, which has a comb-like ink retaining member (surface modified with a copolymer containing vinyl acetate and acrylate ester) as an ink flow rate regulator. A pen writing instrument (Pilot Corporation, fountain pen, FCN-1MR-BM) was mounted with the pen tip facing upward. This writing instrument is used as a test writing instrument.

<Test 1 = Ink mobility test in ink storage body>
Ten test writing instruments each filled with each ink composition were prepared, and when the test writing instrument in the pen tip upward state was placed with the pen tip gently downward, the ink composition was transferred to the ink within 10 seconds. The number of all the drops that flowed down to the pen tip side in the storage was counted, and the ink transfer performance in the ink storage was evaluated according to the following criteria. The obtained evaluation results are summarized in Tables 1 and 2.
A: 10 B: 8-9 C: 5-7 D: 5 or less

<Test 2 = Writing performance test>
The test writing instrument used in Test 1 was placed in a state where the pen tip faced downward for a while, and the filled ink composition was allowed to flow into the pen tip so that writing was possible. In that state, ten consecutive circles were written on the surface of the writing test paper, the handwriting was confirmed, and writing performance was evaluated according to the following criteria. The obtained evaluation results are summarized in Tables 1 and 2. In addition, it evaluated using JISP3201 writing paper A as a writing test paper.
A: A good handwriting without blurring, fading, or back-through was obtained.
B: Smudge or smearing in the handwriting was confirmed.

<Test 3 = Leakage-proof performance test>
The test writing instrument used in Test 2 was placed in a pen tip downward state and allowed to stand in a vacuum desiccator. In this state, the inside of the desiccator was decompressed to 70 mmHg in 5 minutes, and then the test writing instrument was left in the desiccator for another 5 minutes while maintaining the decompressed state of 70 mmHg. The state of the pen tip of the test writing instrument at this time and the presence or absence of ink leakage were confirmed, and leakage resistance performance was evaluated according to the following criteria. The obtained evaluation results are summarized in Tables 1 and 2.
A: Ink leakage did not occur.
B: When the pressure in the desiccator was reduced to 70 mmHg in 5 minutes, no ink leakage occurred, but a small amount of ink composition was blown out from the pen tip during 5 minutes while maintaining the reduced pressure state of 70 mmHg. Some ink leakage occurred. However, it was a level with no practical problem.
C: When the pressure in the desiccator was reduced to 70 mmHg in 5 minutes, ink leakage occurred.

  As shown in Table 1, the ink compositions of Examples 1 to 6 were at good levels in all of the ink transfer performance, writing performance, and leakage resistance performance in the ink reservoir.

  On the other hand, as shown in Table 2, since the ink compositions of Comparative Examples 1 and 3 do not use alkanolamine, the ink compositions of Comparative Examples 2 and 3 use polyoxyethylene tribenzylphenyl ether. Therefore, the ink composition did not satisfy all of the ink transfer performance, writing performance, and leak-proof performance in the ink storage body.

  Furthermore, after knocking the test writing instrument and extending the pen tip and leaving it for 30 minutes at 20 ° C. and 65% RH, continuously write the letter “V” (the size of the letter is about 8 mm in length and width). The writing instrument using the ink composition of Example 1 comprising two of polyoxyethylene tribenzylphenyl ether and alkanolamine was counted as polyoxyethylene when the number of characters until the handwriting was recognizable was counted. Compared to the writing tools using the ink compositions of Comparative Examples 2 and 3 that did not contain tribenzylphenyl ether and alkanolamine, the number of characters until recovery was small, dry-up resistance, and writing performance tended to be excellent. .

  The writing instrument using the ink composition of Example 1 comprising polyoxyethylene tribenzylphenyl ether and alkanolamine is the ink of Comparative Examples 2 and 3 not containing polyoxyethylene tribenzylphenyl ether and alkanolamine. Compared to a writing instrument using the composition, the ink ejection from the pen tip was good, and there was a tendency to produce a dark handwriting with excellent color development.

Based on the above, the water-based ink composition for writing instruments comprising water, a colorant, polyoxyethylene tribenzylphenyl ether, and alkanolamine is excellent in ink transfer performance in the ink reservoir, and can be stably applied to the pen tip. , Excellent ink ejection from the pen tip, no blur, back-through, or fading, resulting in a dark, well-colored handwriting, and no ink leakage even under sudden pressure changes It was found to have good leakage resistance. Furthermore, it has excellent dry-up resistance, and even when the pen tip is exposed to the atmosphere for a while, it can provide good handwriting, and the pen tip can always be exposed to the atmosphere. It has been found that such a penetrating writing instrument produces good handwriting.
Therefore, the water-based ink composition for writing instruments of the present invention is excellent in ink transfer performance and leakage resistance in the ink storage body, but can leave good handwriting, and further uses the ink composition of the present invention. It has been found that the writing instrument is excellent as a writing instrument.

The ink composition of the present invention can be used as a water-based ink composition for various writing instruments such as fountain pens, ballpoint pens, brush pens, calligraphic pens, and marking pens. In particular, since the ink transfer performance and leakage resistance in the ink storage body are improved, the ink storage body can be suitably used for a writing instrument including an ink flow rate adjusting body in an ink supply mechanism. Furthermore, it can be effectively used in a writing instrument, particularly a fountain pen, in which comb-like ink retaining members are arranged as an ink flow rate adjusting body.

Claims (4)

  A water-based ink composition for a writing instrument, comprising water, a colorant, polyoxyethylene tribenzylphenyl ether, and alkanolamine.   The ink composition according to claim 1, further comprising a chelating agent.   The ink composition according to claim 1 or 2, wherein the polyoxyethylene tribenzylphenyl ether has an HLB value of 6 to 20. A writing instrument comprising the ink composition according to any one of claims 1 to 3.