JP2018168248A - Water-based ink composition for writing instruments and writing instrument using the same - Google Patents

Abstract

To provide a water-based ink composition for a writing instrument, which is excellent in dry-up performance, ink followability, and water resistance of handwriting, and a writing instrument using the same. An ink storage unit that supplies a writing tip and an ink storage unit that supplies the writing tip, and ink can be supplied from the ink storage unit to the writing tip between the writing tip and the ink storage unit. A water-based ink composition for a writing instrument that is incorporated in a writing instrument in which a comb-like ink retaining member that temporarily holds the ink is disposed as an ink flow rate regulator, the ink composition comprising water, a pigment, and N , N, N-trialkylamino acid and a water-based ink composition for a writing instrument containing urethane-based film-forming resin particles, and a writing instrument using the same. [Selection figure] None

Description

  The present invention relates to a water-based ink composition for a writing instrument and a writing instrument using the same. More specifically, the present invention relates to a water-based ink composition for a writing instrument having excellent dry-up resistance when used in a writing instrument and water resistance of a handwriting, and a writing instrument using the same.

  Conventionally, low-viscosity inks that use pigments as colorants have been filled into fountain pens and ballpoint pens, and written on writing media. In particular, the ink should have excellent water resistance and light resistance. Because of this, it has been actively studied. However, the ink using a pigment as a colorant is used for a writing instrument such as a fountain pen, in which a comb-like ink retaining member that can supply ink from the ink storage unit to the writing tip is arranged as an ink flow rate regulator. If the writing tip is exposed to the atmosphere for a while, the ink may dry and solidify in the writing tip or the ink flow path, which may cause the ink flow path to become smudged or impossible to write. It was. Unlike the case of using a dye as a colorant, pigment-based inks are difficult to completely block the ink flow path because the pigment is difficult to completely redisperse even if the ink is supplied later. there were. Thus, in a writing instrument using pigment-based ink, improvement in dry-up resistance has been a problem to be solved. Therefore, in order to solve the problems, various studies have been made such as using water-soluble organic solvents such as polyhydric alcohols and materials having a moisturizing effect such as urea, urea derivatives, and trimethylglycine as a humectant in the aqueous ink composition. (For example, Patent Document 1). Although these studies can achieve dry-up resistance, the ink viscosity increases, making it difficult to use for fountain pens, and the water resistance of handwriting, which is one of the characteristics of pigment inks, may be inferior. there were. As described above, the ink using the pigment as the colorant has room for improvement in order to satisfy both the dry-up resistance and the water resistance simultaneously.

Japanese Patent Laying-Open No. 2006-151003

  The present invention has a writing tip and an ink storage unit that supplies the writing tip, and between the writing tip and the ink storage unit, ink can be supplied from the ink storage unit to the writing tip, and overflow due to an increase in internal pressure of the ink storage unit This is a water-based ink composition for writing instruments that has a comb-like ink retaining member that temporarily retains the ink used as an ink flow rate adjusting body, and has excellent dry-up resistance and ink followability. The present invention provides a water-based ink composition for a writing instrument excellent in water resistance (sometimes simply referred to as “water-based ink composition” or “ink composition”) and a writing instrument using the same.

The present invention has solved the above-mentioned problems by making the water-based ink composition for writing instruments a water-based ink composition containing N, N, N-trialkylamino acid and urethane film-forming resin particles.
That is, the present invention
“1. It has a writing tip and an ink storage part to be supplied to the writing tip, and between the writing tip and the ink storage part, ink can be supplied from the ink storage part to the writing tip, and overflowed due to an increase in internal pressure of the ink storage part. A water-based ink composition for a writing instrument, which is incorporated in a writing instrument in which a comb-like ink retaining member (hereinafter sometimes referred to as "pen core") that temporarily holds ink is disposed as an ink flow rate regulator, A water-based ink composition for a writing instrument, wherein the ink composition comprises water, a pigment, N, N, N-trialkylamino acid, and urethane-based film-forming resin particles.
2. Item 1. The viscosity of the ink composition measured at 20 rpm with a rotation speed of 60 rpm using a B-type rotational viscometer is 1.0 to 3.0 mPa · s. Water-based ink composition for writing instruments.
3. Item 1 or Item 2 is characterized in that the mixing ratio of the N, N, N-trialkylamino acid and the urethane-based film-forming resin particles is 1: 0.05 to 1: 1 on a mass basis. A water-based ink composition for a writing instrument as described in 1.
4). A writing instrument comprising the water-based ink composition for a writing instrument according to any one of items 1 to 3. ".

  According to the present invention, by including N, N, N-trialkylamino acid and urethane-based film-forming resin particles in the ink composition, the writing is improved even when the writing tip is exposed to the atmosphere, and the dry-up resistance is improved. It has excellent effects such as improved properties and improved water resistance of the obtained handwriting.

  The water-based ink composition for a writing instrument according to the present invention has a writing tip and an ink storage part to be supplied to the writing tip, and is incorporated in a writing tool in which a pen core is disposed as an ink flow rate adjusting body between the writing tip and the ink storage part. One feature is that the water-based ink composition for writing instruments contains water, a pigment, N, N, N-trialkylamino acid, and urethane-based film-forming resin particles.

The water-based ink composition for a writing instrument used in the present invention comprises N, N, N-trialkylamino acid.
Since the N, N, N-trialkylamino acid has high moisture absorption performance, it functions as a humectant and can prevent evaporation of ink moisture from the writing tip. N, N, N-trialkylamino acids have extremely high moisture retention during drying compared to other humectants. For this reason, the water-based ink composition containing N, N, N-trialkylamino acid can effectively control the evaporation of water in the ink for a long period of time even in a severe dry state. Become. Accordingly, when a water-based ink composition comprising N, N, N-trialkylamino acid is used for a writing instrument, the writing tip is exposed to the atmosphere for a long period of time or in a dry environment. In addition, the high moisturizing effect results in good writing. Further, it is possible to prevent the ink from being solidified at the writing tip or the ink flow path and clogging the ink flow path so that the handwriting is faded or cannot be written.

The N, N, N-trialkylamino acid can be represented by the following formula (1).

As R _{1 to} R ₃ , a linear or branched alkyl group can be widely used. That is, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like are exemplified. R _{1 to} R ₃ may be the same or different. Specific examples include trimethylglycine with n = 1, triethylglycine, tripropylglycine, triisopropylglycine, n = 2 trimethyl-β-alanine, n = 3 trimethyl-γ-aminobutyric acid, and the like. In view of improvement in dry-up resistance and improvement in storage stability of the water-based ink composition, it is preferable to select and use trimethylglycine.

  The content of the N, N, N-trialkylamino acid in the water-based ink composition used in the present invention is preferably 1 to 10% by mass, and 1 to 7% by mass based on the total mass of the water-based ink composition. % Is more preferable. If the content of N, N, N-trialkylamino acid is within the above range, it is possible to effectively obtain the high moisture absorption performance of N, N, N-trialkylamino acid and the high water retention ability during drying, The effect brought about by the water-based ink composition of the present invention can be sufficiently obtained.

  The urethane-based film-forming resin particles used in the present invention are those in which the urethane-based resin is stably dispersed in the ink composition without being dissolved in water. It binds and forms a film.

  The mixing ratio of the urethane-based film-forming resin particles used in the present invention is 0.1% or more and preferably 2.0% by mass or less with respect to the total mass of the ink composition. More preferably, it is 0.1% by mass or more and 0.5% by mass or less. If it is larger than this range, the viscosity of the ink composition will increase, making it difficult to pass through the ink flow path when writing, and there is a possibility that the handwriting will be blurred or unable to be written. Furthermore, film formation becomes easier and the ink may solidify at the writing tip. If it is smaller than this range, no film is formed in the handwriting, and no film is formed, or it takes time to form the film, and the water resistance tends to be poor.

  As the urethane-based film-forming resin particles used in the present invention, polyether polyol copolymer type, polyester polyol copolymer type, polycarbonate polyol copolymer type urethane emulsion and the like can be used. In addition, when the urethane-based film-forming resin particles are blended in the ink composition, a urethane-based film-forming resin dispersed in water may be added to the ink composition. A film-forming resin may be dispersed.

  The water-based ink composition for a writing instrument according to the present invention comprises N, N, N-trialkylamino acid and urethane film-forming resin particles, and supplies the ink composition to the writing tip and the writing tip. And when used in a writing instrument in which a pen core is disposed as an ink flow rate adjusting body between the writing tip and the ink storage part, the dry-up resistance and the water resistance of the handwriting are improved. The reason why it is possible to achieve compatible performances is considered to be as follows.

  That is, since the N, N, N-trialkylamino acid functions as a humectant in the ink composition as described above, it suppresses moisture evaporation at the writing tip. At the tip of writing, the urethane-based film-forming resin particles have a function of preventing fusion and film formation to form a continuous film. For this reason, since the resin does not form a film in the ink flow path of the writing tip or the pen core, the dry-up resistance is improved.

  And the handwriting obtained at the time of writing increases the ratio of the resin in the ink composition on the paper when the N, N, N-trialkylamino acid penetrates into the paper together with the moisture in the ink composition. Since the effect of suppressing resin fusion and film formation by N, N, N-trialkylamino acid is relatively attenuated, the resin is fused and formed from the emulsion state to form a continuous film. . At that time, the film is formed in a state where the pigment is taken into the continuous film. And even when the handwriting comes into contact with water, such as by dropping water on the handwriting, the resin film shows an irreversible behavior so that it does not return to the emulsion state again. It is thought to improve. In addition, when the handwriting is formed with an ink composition that does not contain urethane-based film-forming resin particles, when water is added dropwise, due to the action of a moisturizing agent and an emulsifier, part or all of the handwriting is in the dropped water. Since it is dispersed or dissolved, the water resistance is inferior, for example, the handwriting is blurred and cannot be seen. However, in the present invention, since the redispersion and re-dissolution of the pigment can be prevented, water resistance is improved. As described above, by using N, N, N-trialkylamino acid and urethane-based film-forming resin particles in combination, it is possible to satisfy both the anti-drying property and the water resistance.

  Film-forming resin particles such as acrylic and olefin, which are film-forming resin particles other than urethane-based film-forming resin particles, form a film due to their slightly lower hydrophilicity than urethane-based resins. Therefore, the function of preventing the formation of a continuous film by forming a film of N, N, N-trialkylamino acid does not sufficiently function, and the dry-up resistance is inferior. Therefore, the use of urethane-based film-forming resin particles is advantageous compared to the case where other film-forming resin particles are used.

  As described above, the water-based ink composition for a writing instrument according to the present invention contains N, N, N-trialkylamino acid and urethane-based film-forming resin particles, so that the relationship between the dry-up resistance and the water resistance of the handwriting conflicts. The ratio of N, N, N-trialkylamino acid: urethane-based film-forming resin particles is 1: 0.05 to 1: 1 on a mass basis. It is preferable that If it is larger than this range, a film may be formed at the tip of writing, and if it is smaller than this range, the water resistance of the handwriting may be inferior. More preferably, it is 1: 0.05-1: 0.5, More preferably, it is 1: 0.05-1: 0.25. Within the above range, the resin can be formed with water resistance without forming a resin film at the writing tip, and both performances can be achieved.

  In the present invention, it comprises an N, N, N-trialkylamino acid, but it may further contain glycerin as a humectant. By using glycerin together, the moisture absorption performance of the water-based ink composition is synergistically improved, a higher moisturizing effect is obtained, and water evaporation in the ink from the writing tip can be effectively prevented. Therefore, in the present invention, the dry-up resistance can be further improved by using a water-based ink composition in which N, N, N-trialkylamino acid and glycerin are used in combination. In the present invention, the combined use of N, N, N-trialkylamino acid and glycerin tends to prevent ink from dropping off from the writing tip while satisfying the dry-up resistance.

  By using N, N, N-trialkylamino acid and glycerin in combination, as described above, while suppressing the increase in viscosity of the water-based ink composition while obtaining a sufficient moisturizing effect, the value of the surface tension of the water-based ink composition Can be kept appropriate. For this reason, a water-based ink composition comprising a combination of glycerin and N, N, N-trialkylamino acid exhibits a sufficient function as an ink flow rate regulator when used in a writing instrument provided with a pen core. Appropriate ink viscosity that can be obtained and appropriate wettability with respect to the ink retaining member can be secured. Therefore, even when the internal pressure of the ink storage portion increases, the overflowed ink smoothly enters the pen core, and the ink can be held in the pen core without flowing too much directly to the writing tip. Therefore, in a water-based ink composition used for a writing instrument in which a pen core is arranged as an ink flow rate regulator, the combined use of glycerin and N, N, N-trialkylamino acid is not only dry-resistant and water-resistant but also resistant to water. Since it is possible to achieve both the drop-off performance, it is more preferable.

  The content of glycerin in the aqueous ink composition for writing instruments according to the present invention is preferably 1 to 10% by mass, more preferably 1 to 7% by mass, based on the total mass of the aqueous ink composition. If the content of glycerin is within the above range, it is possible to suppress an increase in ink viscosity, to improve ink following performance and to suppress ink dropping, and to take time until the obtained handwriting is completely dried. Without this, it is possible to prevent the handwriting from being rubbed and soiled before drying.

  The mixing ratio of glycerin and N, N, N-trialkylamino acid in the water-based ink composition according to the present invention is preferably 2: 3 to 3: 2 by mass ratio. Furthermore, it is preferable that it is 1: 1-3: 2. If the blending ratio of glycerin and N, N, N-trialkylamino acid is within the above range, the increase in ink viscosity can be suppressed and the surface tension of the water-based ink composition can be reduced while sufficiently obtaining dry-up performance. It can maintain appropriately and can acquire the effect of the present invention effectively.

<Pigment>
Examples of the pigment that can be used in the present invention include pigments that are usually used in water-based ink compositions for writing instruments.

  The pigment that can be used in the present invention is not particularly limited as long as it can be dispersed in an aqueous medium. For example, inorganic, organic, processed pigments, etc. are mentioned, specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium, Examples thereof include triphenylmethane, perinone, perylene, dioxazine, aluminum pigment, pearl pigment, fluorescent pigment, and phosphorescent pigment. In addition, a microcapsule pigment in which a colored body in which a pigment is dispersed in a medium as a colored resin particle body is encapsulated or solidified in a shell made of a resin wall film forming substance by a known microencapsulation method may be used. good. The pigment may be a water-dispersed pigment product that is finely and stably dispersed in an aqueous medium in advance using a surfactant or a resin.

  Moreover, you may use the said pigment individually or in combination of 2 or more types. Further, it may be used in combination with a dye. The pigment content in the water-based ink composition is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, based on the total weight of the water-based ink composition. It is preferably 5% by mass. When the content of the pigment is within the above range, it is possible to prevent a decrease in ink follow-up performance to the writing tip, and it is possible to obtain a handwriting with good 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.

<Others>
The water-based ink composition according to the present invention may contain various additives such as a pH adjuster, a rust inhibitor, a preservative, and a chelating agent for the purpose of improving ink physical properties and functions.

  Examples of pH adjusters include basic inorganic compounds such as ammonia, sodium carbonate, sodium phosphate, and sodium hydroxide, basic organic compounds such as sodium acetate, triethanolamine, and diethanolamine, lactic acid, and citric acid. Considering the stability over time of the ink composition, it is preferable to use a basic organic compound, and considering more consideration, it is preferable to use triethanolamine which is weakly basic. These pH adjusters may be used alone or in combination of two or more. The content of the pH adjuster is preferably 0.1 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total mass of the water-based ink composition.

  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.

  As chelating agents, ethylenediaminetetraacetic acid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), glycol etherdiaminetetraacetic acid (GEDTA), nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), dihydroxyethylglycine (DHEG) ), Diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA) and alkali metal salts, ammonium salts or amine salts thereof.

  The writing instrument in which the pen core used in the present invention is arranged as an ink flow rate adjusting body can be used by the user repeatedly replenishing ink, and the replenishing ink may be accommodated in an ink container such as a glass bottle. Glass bottles are inexpensive and easy to mold, and can easily achieve the desired strength, but when using cheap and versatile soda-lime glass, etc. In addition, there is a high possibility that an alkali component is eluted from the glass in the water-based ink composition, and this eluted alkali component reacts with a component of the water-based ink composition to form a precipitate. Therefore, in the water-based ink composition used in the present invention, the alkali component eluted from the glass ink container is supplemented, and the alkali component reacts with the component in the water-based ink composition to precipitate insoluble in water. It is preferable to include the chelating agent that can prevent the ink flow path from being blocked by the generated precipitates and the like, thereby preventing the handwriting from being smeared or writing impossible. Considering that the alkali component can be sufficiently supplemented and that there is no change in physical properties and performance before and after the mixing of the chelating agent of the aqueous ink composition, among the chelating agents, ethylenediaminetetraacetic acid (EDTA) is used. It is preferable.

  Furthermore, a water-soluble organic solvent may be added, and a fluorine-based surfactant that improves the permeability of the solvent, a non-foaming agent such as a nonionic, anionic, or cationic surfactant or dimethylpolysiloxane is added. You can also

  The viscosity of the water-based ink composition for writing instruments used in the present invention is preferably 1.0 to 3.0 mPa · s as measured by a B-type rotational viscometer at a rotation speed of 60 rpm and 20 ° C. . If it is larger than this range, when the pen core is used for a writing instrument arranged as an ink flow rate adjuster, the ink is not stably supplied to the tip of the writing, and there is a risk that the handwriting will be faded or unwritable. More preferably, it is 1.0-2.5 mPa * s, More preferably, it is 1.0-2.0 mPa * s. If the ink viscosity is within the above range, the ink tracking performance is improved when the pen core is used in a writing instrument arranged as an ink flow rate adjuster, so that ink is stably supplied to the writing tip and good handwriting is obtained. It is because it can be made.

  Moreover, if the ink viscosity of a water-based ink composition is in the said range, dry-up-proof performance and handwriting drying performance can be improved.

  The ink viscosity in the present invention can be measured according to JIS Z 8803: 2011 with a B-type rotational viscometer (model: BLII, rotor: BL adapter, manufactured by Toki Sangyo Co., Ltd.).

  The surface tension of the water-based ink composition used in the present invention at 20 ° C. is preferably 30 to 70 mN / m, and more preferably 35 to 70 mN / m. When the surface tension of the water-based ink composition is within the above numerical range, the wettability with respect to the ink retaining member can be kept moderate when used in a writing instrument provided with a pen core. Therefore, even when the internal pressure of the ink storage unit increases, the overflowed ink can smoothly enter the pen core, and the ink drop off from the writing tip can be effectively suppressed. Furthermore, since the wettability with respect to the writing surface is also maintained appropriately, it is possible to prevent the obtained handwriting from bleeding, or the handwriting from drying out and being rubbed and soiled before it is dried. The surface tension is determined by measuring by a vertical plate method using a platinum plate using a surface tension measuring instrument (model: CBVP-A3) manufactured by Kyowa Interface Science Co., Ltd. in a 20 ° C. environment.

<Method for producing ink composition>
The water-based ink composition according to the present invention can be produced by any conventionally known method. Specifically, it can be produced by blending the required amounts of the above components and mixing them with various stirrers such as magnetic stirrer stirring, propeller stirring, homodisper, or homomixer, or various dispersers such as bead mills. .

<Writing instruments>
The writing instrument used in the present invention has a writing tip and an ink storage unit that supplies the writing tip, and ink can be supplied from the ink storage unit to the writing tip between the writing tip and the ink storage unit, and the internal pressure of the ink storage unit increases. A writing instrument is used in which a comb-like ink retaining member that temporarily retains the overflowed ink is disposed as an ink flow rate adjusting body. The comb-like ink retaining member supplies a water-based ink composition from the ink storage unit to the writing tip as an ink flow rate regulator, and temporarily transfers the water-based ink composition that overflows as the internal pressure of the ink storage unit increases. It is possible to hold it.

  As described above, the writing instrument used in the present invention has a high possibility of separating and replenishing the water-based ink composition from the ink container in which the water-based ink composition is stored. Therefore, it is preferable to consider the water-based ink composition for writing instruments according to the present invention even when stored and stored in an ink container. For example, it is assumed that the water-based ink composition stored in the ink container is repeatedly collected from the opening of the ink container, and moisture in the water-based ink composition tends to easily evaporate from the opening. Yes, the ink viscosity may increase and the physical properties may change, and because it contains urethane-based film-forming resin particles that can be formed into a film, when the water evaporates, the ink in the ink container There is a risk of forming a film. Further, as described above, the ink container is highly likely to use a glass bottle, and a precipitate may be generated due to a reaction between an alkaline component eluted from the ink container and a component of the water-based ink composition. . Accordingly, the water-based ink composition used in the present invention contains an N, N, N-trialkylamino acid having high moisture absorption performance and having an effect of suppressing the formation of urethane-based film-forming resin particles. Even when stored, stored and used in a container, it is possible to effectively prevent water evaporation and film formation in the water-based ink composition, and further include a chelating agent. Therefore, it is possible to prevent the generation of precipitates caused by the reaction with the alkaline component eluted from the ink container. Therefore, the water-based ink composition for a writing instrument according to the present invention, which contains an N, N, N-trialkylamino acid and can further contain a chelating agent, is stored and stored in an ink container such as a glass bottle. Even in this case, it is possible to suppress moisture evaporation, prevent the generation of precipitates, and have excellent storage stability. Therefore, it can be suitably used for a writing instrument in which the pen core is arranged as an ink flow rate regulator.

  Moreover, the writing instrument incorporating the water-based ink composition for a writing instrument according to the present invention is a writing instrument in which a pen core is disposed as an ink flow rate adjusting body. Specific examples of the writing instrument include a fountain pen, a ballpoint pen, and a calligraphic pen. Can be mentioned.

  Examples of these writing tools include a cap-type writing tool having a cap that covers the writing tip, and a retractable writing tool having a retracting mechanism that can accommodate the writing tip in the shaft cylinder of the writing tool. In particular, since the writing tool is less airtight at the tip of the writing than the cap-type writing tool, a problem tends to occur in the dry-up resistance of the writing tip. Therefore, when the water-based ink composition for a writing instrument according to the present invention is used, it has excellent dry-up resistance, and thus can be suitably used as a water-based ink composition for a retractable writing instrument.

  Among the writing instruments, in particular, the fountain pen is exposed to the outside air at the time of writing, the ink at the writing tip tends to evaporate, and it is necessary to improve the anti-drying-up performance of the writing tip. Furthermore, since the ink viscosity of the water-based ink composition used for the fountain pen is extremely low, it is easy for the ink to leak out from the writing tip, and in particular, it is necessary to consider the suppression of ink dropping from the writing tip. Therefore, the water-based ink composition for a writing instrument according to the present invention is excellent in dry-up resistance and anti-fogging performance, and is therefore extremely effective for use in a fountain pen.

In addition, since the fountain pen can be used directly by the user by separating the ink from an ink container such as a glass bottle and replenishing it in the ink storage unit, the ink often touches the user's skin. For this reason, it is necessary to consider the safety | security with respect to the human body of the water-based ink composition used. The N, N, N-trialkylamino acid and glycerin used in the present invention are excellent in safety to the human body. Among them, among the N, N, N-trialkylamino acids, trimethylglycine is one of amino acids. Yes, it is one of the natural substances that can be extracted from plants such as sugar beet, purified and crystallized, and is extremely safe for the human body. Thus, also from the viewpoint of safety to the human body, the water-based ink composition of the present invention can be suitably used for a fountain pen.
From the above, the ink composition for writing instruments of the present invention can be suitably used particularly as a fountain pen.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Example 1
A water-based ink composition for a writing instrument was obtained by the following composition and method.
・ Pigment 30.8% by mass
(Product name: BONJET BLACK CW-3, manufactured by Orient Chemical Co., Ltd.)
Carbon black 13% aqueous dispersion of carbon black)
-Urethane-based film-forming resin particles A 0.3% by mass
(Adeka Co., Ltd. product name: Adekabon titer HUX-370
(Resin content 33.3%)
・ N, N, N-trialkylamino acid (trimethylglycine) 2.0 mass%
・ Glycerin 3.0% by mass
・ Triethanolamine (pH adjuster) 1.0% by mass
-Preservative (1,2-benzisothiazolin-3-one 9.5% aqueous solution) 0.2% by mass
-Water remainder A moisturizer, pH adjuster, preservative, and water were mixed by propeller stirring to obtain a base solution. Thereafter, a pigment was added to the base liquid and mixed by stirring with a propeller, and then urethane-based film-forming resin particles were mixed to obtain a water-based ink composition. The viscosity of the obtained water-based 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) according to JIS Z 8803: 2011. Specifically, the ink viscosity at 20 ° C. and a rotation speed of 60 rpm was 1.77 mPa · s. Moreover, when the surface tension of the obtained water-based ink composition was measured with a surface tension measuring instrument (model: CBVP-A3, manufactured by Kyowa Interface Science Co., Ltd., 20 ° C. environment, platinum plate, vertical plate method), 51 0.5 mN / m.

(Example 2 to Example 4, Comparative Example 1 to Comparative Example 5)
A water-based ink composition for writing instruments of Examples 2 to 4 and Comparative Examples 1 to 5 in the same manner as in Example 1 except that the formulation shown in (Table 1) was used for Example 1. I got a thing.

・顔料：オリヱント化学工業株式会社製 商品名：ＢＯＮＪＥＴ ＢＬＡＣＫ ＣＷ−３ カーボンブラック カーボンブラック１３％水分散体
・ウレタン系造膜性樹脂粒子Ａ：株式会社ＡＤＥＫＡ製 商品名：アデカボンタイターＨＵＸ−３７０ 樹脂分３３．３％
・ウレタン系造膜性樹脂粒子Ｂ：株式会社ＡＤＥＫＡ製 商品名：アデカボンタイターＨＵＸ−５６１Ｓ 樹脂分３８．８％
・ウレタン系造膜性樹脂粒子Ｃ：株式会社ＡＤＥＫＡ製 商品名：アデカボンタイターＨＵＸ−５６４ 樹脂分４０．１％
・オレフィン系造膜性樹脂粒子：住友精化株式会社製 商品名：ザイクセンＬ 樹脂分２５％
・アクリル系造膜性樹脂粒子：株式会社ピース電気製 商品名：セラゾール２２００ 樹脂分２１．９％
・シリコーン系造膜性樹脂粒子：エボニック社製 商品名：ＴＥＧＯ Ｐｈｏｂｅ１６５９
・防腐剤：１，２−ベンズイソチアゾリン−３−オン ９．５％水溶液

-Pigment: manufactured by Orient Chemical Co., Ltd. Product name: BONJET BLACK CW-3 Carbon black 13% aqueous dispersion of carbon black-Urethane film-forming resin particles A: manufactured by ADEKA Co., Ltd. Product name: Adekabon titer HUX-370 Resin 33.3%
-Urethane-based film-forming resin particles B: manufactured by ADEKA Corporation Product name: Adekabon titer HUX-561S Resin content 38.8%
-Urethane-based film-forming resin particles C: manufactured by ADEKA Corporation Product name: Adekabon titer HUX-564 Resin content 40.1%
・ Olefin-based film-forming resin particles: manufactured by Sumitomo Seika Co., Ltd. Product name: XYZEN L 25% resin content
-Acrylic film-forming resin particles: manufactured by Peace Electric Co., Ltd. Trade name: Cerazole 2200, resin content 21.9%
-Silicone-based film-forming resin particles: manufactured by Evonik Co., Ltd. Trade name: TEGO Phobe 1659
Preservative: 1,2-benzisothiazolin-3-one 9.5% aqueous solution

(Microscopic observation)
Ink was dropped on the slide glass, and a cover glass was placed thereon to prepare a slide. The preparation was observed at a magnification of 100 times with transmitted light using a system biological microscope (model: BX51) manufactured by Olympus Optical Co., Ltd.
○: The film-forming resin particles are uniformly and stably dispersed in the ink composition.
X: The film-forming resin particles cannot be dispersed in the ink composition and are separated.

(Examination and evaluation)
The writing tool water-based ink compositions of Examples 1 to 4 and Comparative Examples 1 to 5 are poured into an ink cartridge made of polyethylene, and the penetrating writing instrument having a fountain pen-shaped writing tip (stock) It was mounted on a company pilot corporation fountain pen (FCN-1MR-BM) and evaluated as a test writing instrument.

(Test 1 = Dry-up resistance test)
Knock the writing instrument for test, let out the writing tip, leave it for 30 minutes under the condition of 20 ℃ and 65% RH, then continuously write the letter "V" (letter size is about 8mm in length and width) The number of characters before returning to an extent that can be recognized was counted, and the dry-up resistance was evaluated according to the following evaluation criteria. In addition, evaluation was performed using high-quality paper (Shiraoi 4 / 6T) manufactured by Nippon Paper Industries Co., Ltd. as a writing test paper.
A: The number of characters until handwriting return was less than 0.5 characters.
○: The number of characters until handwriting return was 0.5 or more and less than 1 character.
Δ: The number of characters until handwriting return was 1 or more and less than 10 characters.
X: The number of characters until handwriting return was 10 or more and less than 20 characters.
Xx: The number of characters until handwriting return was 20 characters or more.

(Test 2 = water resistance test)
Using the test writing instrument used in test 1, a straight line was continuously written under the conditions of a writing angle of 60 °, a writing load of 0.49 N, and a writing speed of 10 m / min, and the resulting handwriting was left for 24 hours, and then dropped into a dropper. Then, water was dropped onto the handwriting, the state of the handwriting was visually confirmed, and water resistance was evaluated according to the following criteria.
○: The handwriting did not bleed at all and kept the same state as before the water was dropped.
Δ: The handwriting was slightly blurred but could be confirmed as the handwriting.
X: A handwriting flowed and it did not have water resistance at all.

  In Examples 1 to 4, in comparison with the comparative example, the balance between the dry-up resistance and the water resistance was excellent and excellent, and the performances of the dry-up resistance and the water resistance conflicted with each other. On the other hand, Comparative Examples 1 to 4 were inferior in either dry-up resistance or water resistance or both, and could not achieve conflicting performances. In Comparative Example 5, the film-forming resin particles caused phase separation in the ink composition and were not established as a water-based ink composition.

  The water-based ink composition for a writing instrument of the present invention can be suitably used as an ink composition for a writing instrument in which a pen core is disposed as an ink flow rate regulator, such as a fountain pen, a ballpoint pen, a brush pen, a calligraphy pen, and various markers.

Claims (4)

  There is a writing tip and an ink storage unit that supplies the writing tip. Between the writing tip and the ink storage unit, ink can be supplied from the ink storage unit to the writing tip, and the ink that has overflowed as the internal pressure of the ink storage unit rises temporarily. A water-based ink composition for a writing instrument, which is incorporated in a writing instrument in which a comb-like ink retaining member is held as an ink flow rate regulator, and the ink composition contains water, a pigment, N, N, N -A water-based ink composition for a writing instrument, comprising a trialkylamino acid and urethane-based film-forming resin particles.   2. The viscosity of the ink composition when measured at a rotation speed of 60 rpm and 20 ° C. using a B-type rotational viscometer is 1.0 to 3.0 mPa · s. Water-based ink composition for writing instruments.   The blending ratio of the N, N, N-trialkylamino acid and urethane-based film-forming resin particles is 1: 0.05 to 1: 1 on a mass basis. Water-based ink composition for writing instruments.   A writing instrument comprising the water-based ink composition for a writing instrument according to any one of claims 1 to 3.