JP2012012468A - Water-based ink composition for writing utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ink composition for a writing utensil, which is excellent in the dry-up performance and with which writing is possible on an impermeable surface.SOLUTION: The water-based ink composition for a writing utensil includes, at least, water, a colorant, a dry-up inhibitor, and a surfactant. The solubility of the dry-up inhibitor to water at 20°C is 3.0 to 20.0 mass%, and the surface tension at 20°C of the ink composition is 20 to 40 mN/m.

Description

  The present invention relates to a water-based ink composition for writing instruments, and more particularly to a water-based ink composition for writing instruments that has excellent dry-up performance and can be written on a non-penetrating surface.

  Conventionally, if the cap is removed from the writing instrument body and the nib is left in the atmosphere, the solvent in the ink evaporates, and the colorant and resin dry and solidify, resulting in poor writing and poor writing. There was a case.

  Therefore, water-based ink compositions for writing instruments with improved dry-up performance using polyhydric alcohol solvents such as ethylene glycol and propylene glycol, urea and / or urea derivatives are known as pen tip drying inhibitors for water-based inks for writing instruments. It has been.

   However, the former polyhydric alcohol solvents such as ethylene glycol and propylene glycol need to be added in a large amount in order to obtain sufficient dry-up performance. As a result, ink follow-up failure due to an increase in ink viscosity, blurring of handwriting, etc. Furthermore, the handwriting drying property is inferior, and the handwriting drying property is remarkably inferior on the non-penetrating surface of a plastic, a metal material or the like. In addition, although the latter urea and / or urea derivative is recognized to have some improvement in dry-up performance, it decomposes in a high temperature environment to generate ammonia, which causes a problem that the ink aging becomes unstable.

  In view of these problems, Japanese Patent No. 3507514 “Aqueous ink composition” contains salicylic acid, Japanese Patent Application Laid-Open No. 9-67535 “Aqueous ink composition” contains serine, JP-A-2010-37369 “Ink for Writing Instruments” discloses one containing dipentaerythritol.

“Patent No. 3507514” "Japanese Patent Laid-Open No. 9-67535" "JP 2010-37369 A"

  As described in Patent Documents 1 to 3, by including a dry-up inhibitor newly, some performance improvement is recognized, but a large amount of the dry-up inhibitor is precipitated in the ink, There was a problem in handwriting blurring and writing defects, and the dry-up inhibitor was not dissolved and stabilized in the ink, resulting in stability over time. In particular, at low temperatures (0 to 10 ° C.), the solubility in water is lower than at room temperature (about 20 ° C.), and due to disadvantageous conditions, a large amount of dry-up inhibitor is precipitated in the ink. There was a problem of handwriting scraps and writing defects. In recent years, there has been a demand for writing instruments that can be written not only on paper but also on non-penetrating surfaces, and additional additives and the like are required to satisfy them.

  An object of the present invention is to provide a water-based ink composition for a writing instrument that has excellent dry-up performance, has good handwriting, and can also be written on a non-penetrating surface.

In order to solve the above problems, the present invention
“1. A water-based ink composition for a writing instrument containing at least water, a colorant, a dry-up inhibitor, and a surfactant, wherein the solubility of the dry-up inhibitor in water at 20 ° C. is 3.0 to 20. The surface tension of the water-based ink composition for a writing instrument at 20 ° C. is 20 to 40 mN / m.
2. The water-based ink composition for a writing instrument according to item 1, wherein the dry-up inhibitor is a higher alcohol-based dry-up inhibitor.
3. Content of the said dry-up inhibitor is 0.1-20.0 mass% with respect to content with respect to the water in 20 degreeC, The aqueous | water-based for writing instruments of the 1st term | claim or the 2nd item | term characterized by the above-mentioned Ink composition.
4). Item 1 to Item 3, wherein the surfactant contains one or more selected from silicon surfactants, acetylene glycol surfactants, fluorine surfactants, and dialkylsulfosuccinates. A water-based ink composition for a writing instrument as described in 1.
5. The water-based ink composition for a writing instrument according to any one of claims 1 to 4, wherein the surfactant is a polyether-modified silicone oil and the content is 0.01 to 5.00% by mass. "
And

The present invention is a water-based ink composition for a writing instrument containing at least water, a colorant, a dry-up inhibitor, and a surfactant,
The solubility in water at 0 ° C. is 3.0 to 20.0 mass%, and the surface tension at 20 ° C. of the water-based ink composition for writing instruments is 20 to 40 mN / m. It was possible to provide a water-based ink composition for a writing instrument that has excellent up-performance and that can also be written on a non-penetrating surface.

  A feature of the present invention is that a dry-up inhibitor having a water solubility at 20 ° C. of 3.0 to 20.0% by mass and a surfactant are used in combination, and the aqueous ink composition for writing instruments at 20 ° C. The surface tension is 20 to 40 mN / m.

  As a result of intensive investigations by the inventors of the present invention regarding the dry-up inhibitor, when the dry-up inhibitor having a solubility of 3.0 to 20.0% by mass is used, the moisture in the ink is reduced in a state where the cap is removed. By evaporating, it is possible to form a film that suppresses evaporation of the solvent at the nib, and to suppress further evaporation of water, thereby improving the dry-up performance.

  When a dry-up inhibitor having a solubility of less than 3.0% by mass is used, it cannot contain a sufficient amount to obtain a dry-up inhibitory effect, and the solubility exceeds 20.0% by mass. When an up inhibitor is used, it is difficult to precipitate the crystalline substance, and a film cannot be sufficiently formed with the pen tip, and a dry up inhibiting effect cannot be obtained. Therefore, it is necessary to use a dry-up inhibitor having a solubility of 3.0 to 20.0% by mass. In consideration of the low solubility in water at low temperatures (0 to 10 ° C.), the solubility is preferably a 5.0 to 20.0 mass% dry-up inhibitor, most preferably, It is a dry-up inhibitor having a solubility of 10.0 to 15.0% by mass.

  Furthermore, in recent years, in order to be able to write with good handwriting not only on paper but also on non-penetrating surfaces, the dry-up inhibitor having a solubility of 3.0 to 20.0% by mass can be used alone. However, sufficient wettability to the non-penetrating surface cannot be obtained, and it is difficult to write well on the non-penetrating surface. Therefore, the surface tension at 20 ° C. of the water-based ink composition for writing instruments needs to be 20 to 40 mN / m using a surfactant. When the surface tension is lower than 20 mN / m, the ink bleeds into the handwriting and the paper breakthrough occurs. When the surface tension exceeds 40 mN / m, the wettability to the non-penetrating surface is inferior. Since the ink is repelled, the surface tension needs to be 20 to 40 mN / m, and preferably 25 to 35 mN / m.

  For dry-up inhibitors having a solubility of 3.0 to 20.0% by mass, lower alcohols (1 to 4 carbon atoms), higher alcohols (5 or more carbon atoms), aromatic alcohols, alicyclic rings There are types such as formula alcohol type, organic acid type and hydantoin type.

  Among them, when higher alcohol-based dry-up inhibitors are used, the deposition rate increases and a film is formed immediately, which suppresses solvent evaporation at the nib and makes it easier to obtain better dry-up performance. Become. Therefore, it is preferable to use a higher alcohol-based dry-up inhibitor.

  Moreover, when the content of the dry-up inhibitor whose solubility is 3.0 to 20.0% by mass exceeds 20.0% by mass with respect to the content of water, it tends to be unstable over time, If it is less than 0.1% by mass, it is difficult to obtain the desired dry-up performance. Therefore, the content is preferably 0.1 to 20.0% by mass with respect to the water content. More preferably, it is 0.1-10.0 mass%. Most preferably, it is 3.0-8.0 mass%.

  Examples of the dry-up inhibitor having a solubility of 3.0 to 20.0% by mass include pentaerythritol (solubility in water at 20 ° C .: 7.2% by mass), 2,5-dimethyl-2, 5-hexanediol (same solubility: 12.3% by mass), succinic acid (same solubility: 7.1% by mass), hydantoin (same solubility: 3.8% by mass), 5,5-dimethylhydantoin (same solubility: 11.5% by mass) and hydroquinone (the same solubility: 7.4% by mass). Specifically, pentaerythritol (Wako Pure Chemical Industries, Ltd.), 2,5-dimethyl-2,5-hexanediol (Wako Pure Chemical Industries, Ltd.), hydantoin (Wako Pure Chemical Industries, Ltd.), 5,5-dimethylhydantoin (Wako Pure Chemical Industries, Ltd.) and the like can be mentioned.

  Moreover, as surfactant used in order to make the surface tension at 20 degreeC of the water-based ink composition for writing instruments into 20-40 mN / m, a silicon type surfactant, an acetylene glycol type surfactant, a fluorine type surfactant , Phosphate ester surfactants, and dialkyl sulfosuccinates. Among them, silicon surfactants and acetylene glycol surfactants having good defoaming properties are preferable because they have the effect of suppressing bubbles during the production process and can improve productivity.

  Among the surfactants, in view of the stability over time, non-reactive silicone oils of silicon surfactants are preferable, polyether-modified, methylstyryl-modified, alkyl-modified, higher fatty acid ester-modified, hydrophilic Examples include specially modified, fluorine-modified, silicone oil such as dimethyl and methylphenyl. Among these, polyether-modified silicone oil is most preferable in consideration of solubility in water and antifoaming property.

  If the content of the surfactant is less than 0.01% by mass relative to the total amount of the ink composition, the effect of sufficiently reducing the surface tension cannot be obtained, and if it exceeds 5.00% by mass, the handwriting drying property is inferior. In addition, since the ink tends to become unstable with time, 0.01 to 5.00% by mass is preferable with respect to the total amount of the ink composition. More preferably, it is 0.01-2.00 mass% with respect to the ink composition whole quantity. Most preferably, it is 0.10-1.50 mass%.

  As a specific example, the silicone-based surfactant is a polyether-modified one, and KF351, KF-352, KF-353, KF-354, KF-355, KF-615, KF-618, KF-642, KF643. KF945, KF-6004 (Shin-Etsu Chemical Co., Ltd.), SILWETL-720, FZ-2104, FZ-2191, L-7001, L-7002, Y-7006, L-7600, L-7607 ( Nippon Unicar Co., Ltd.) and TSF4445 (Toshiba Silicone Co., Ltd.). Specific examples of the acetylene glycol surfactants include DYNOL 604, Surfynol 104H, 104A, 104BC, 104DPM, 104PA, 104S, 420S, 420, 440, SE, SE-F, 61. Etc. (Air Products Japan Co., Ltd.). Specific examples of dialkyl sulfosuccinates include Neocor SW-C, Neocor YSW-CE, Neocor YSK (Daiichi Kogyo Seiyaku Co., Ltd.), Perex OT-P, Perex TR, Perex CS, Perex TA (Kao Corporation) ), Aerol OB-70 (Toho Chemical Industry Co., Ltd.), Aerosol MA-80, Aerosol AY-100 (Mitsui Cyanamid Co., Ltd.), Adeka Coal EC (Adeka Co., Ltd.), and the like. Specific examples of the fluorosurfactant include Megafac F-447, F-410, F-553, F-444 (DIC Corporation), DSN-403N (Daikin Industries Co., Ltd.), Novec FC-4430. FC-4432 (Sumitomo 3M Co., Ltd.) and the like. You may use these individually or in mixture of 2 or more types.

  The colorant is not particularly limited, and may be appropriately selected and used. As the dye, direct dyes, acid dyes, basic dyes, metal-containing dyes, various salt-forming dyes, and the like can be used. Examples of pigments include inorganic, organic, and processed pigments. Specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium , Triphenylmethane, perinone, perylene, glyoxazine, aluminum pigment, pearl pigment, fluorescent pigment, phosphorescent pigment, and complementary color 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. Further, colored resin particles in which the pigment is covered with a transparent or translucent resin or the like, or colored resin particles or colorless resin particles colored with a pigment or a dye can also be used. These dyes and pigments may be used alone or in combination of two or more. The content is preferably 1% by mass to 20% by mass with respect to the total amount of the ink composition. In addition, regarding the ink for a writing instrument of the present invention, unlike a dye-based ink, a pigment-based ink is difficult to re-disperse and tends to be inferior in dry-up performance.

  In the present invention, a resin may be used as a fixing agent. Specific examples include water-soluble resins such as acrylic resins, alkyd resins, cellulose derivatives, polyvinyl pyrrolidone, and polyvinyl alcohol, and emulsion resins such as acrylic resin emulsions and styrene-butadiene resin emulsions. You may use these individually or in mixture of 2 or more types. Further, if the resin content is less than 0.1% by mass relative to the total amount of the ink composition, it is difficult to obtain a desired ink viscosity, and if it exceeds 30% by mass, the writing performance may be deteriorated. Therefore, 0.1 mass% or more and 30 mass% or less are preferable.

   Other solvents such as lower and higher alcohols, pH adjusters such as triethanolamine, humectants such as sorbit, rust preventives such as benzotriazole, chelating agents such as ethylenediaminetetraacetic acid, etc. may be added as necessary. Good. You may use these individually or in combination of 2 or more types.

Next, an Example is shown and this invention is demonstrated.
Example 1
Colorant (pigment dispersion) 30.0% by mass
Water 60.0% by mass
Pentaerythritol 3.0% by mass
Silicone surfactant (polyether-modified silicone oil) 1.0% by mass
Water-soluble resin (acrylic resin) 5.0% by mass
1,2-Benzisothiazolin-3-one 1.0% by mass

First, the water-based ink composition for a writing instrument of Example 1 is a pigment dispersion in which pigments are uniformly dispersed (LUMIKOL NKW-6007E (solid content: 34%, Nippon Fluorescent Chemical Co., Ltd.)), water, water-soluble Resin (Johncrill 61J (solid content: 30%, Johnson Polymer Co., Ltd.)), pentaerythritol (Wako Pure Chemical Industries, Ltd.), silicon surfactant (KF-618: Shin-Etsu Chemical Co., Ltd.), 1 , 2-Benzisothiazolin-3-one was accurately weighed in a predetermined amount and heated and stirred with a disper stirrer at 50 ° C. for 1 hour to obtain a water-based ink composition for writing instruments. Ltd. DV-II viscometer (CPE-42 rotor) 20 ° C. were used to measure the ink viscosity at a shear rate 384.0sec ^-1 (rpm 100rpm), 2.82mPa · The surface tension was measured by a vertical plate method using a glass plate with a surface tension measuring instrument manufactured by Kyowa Interface Science Co., Ltd. in an environment of 20 ° C. m.

  The ink viscosity of Examples and Comparative Examples was measured at 20 ° C. using a Brookfield DV-II viscometer (CPE-42 rotor) manufactured by Brookfield, but the water-based ink composition for a writing instrument of the present invention was Since it is a Newtonian ink, the ink viscosity showed substantially the same numerical value even if the shear rate was different.

Examples 2-6
As shown in Table 1, water-based ink compositions for writing instruments of Examples 2 to 6 were obtained in the same procedure as in Example 1 except that each component was changed to the formulation. Table 1 shows the measurement and evaluation results.

Comparative Examples 1-6
The composition of the ink is as shown in Table 2, and Table 2 shows the measurement and evaluation results.

  A marking pen was prepared by filling the commercially available marking pen (manufactured by Pilot Corporation; Super Petit (SEG-10M)) with the water-based ink composition for writing instruments prepared in Examples 1 to 6 and Comparative Examples 1 to 6.

   Examples of the pen core used as the pen tip of the marking pen include a fiber core, a felt core, and a felt core. Further, the structure and shape of the marking pen itself are not particularly limited.

Test and Evaluation The following test and evaluation were performed using the marking pen prepared as described above. In addition, the evaluation of the dry-up performance test and the bleeding test uses JIS P3201 writing paper A as a writing test paper, and the writing test on the non-penetrating surface uses a commercially available transparent acrylic plate by the following test method. Evaluation was performed.

Dry-up performance test: After removing the cap and leaving it in the atmosphere for 24 hours, the state of handwriting when handwritten writing was evaluated.
There is no blur in the handwriting, and the handwriting is good.
Scratches appear in the handwriting, but there are no practical problems
Scratch in the handwriting, poor practicality ・ ・ ・ ×

Written test on non-penetrating surface: Written on a transparent acrylic plate surface and observed.
Writable and practically acceptable ... ○
Scratch or ink repellency in the handwriting, severe and poor practicality ・ ・ ・ ×

Bleeding test: The state of handwriting when handwritten writing was evaluated.
No bleeding or slight bleeding, but no problem in practical use
Bleeding is poor and impractical ...

  From the results shown in Table 1, in Examples 1 to 6, the dry-up performance test, the writing test on the non-penetrating surface, and the bleeding test were both good or practically acceptable.

  From the results of Table 2, in Comparative Examples 1, 3, and 4, a dry-up inhibitor having a water solubility at 20 ° C. of 3.0 to 20.0 mass% was not used, so that the dry-up performance was poor.

  In Comparative Example 2, the surfactant was not used and the wettability was insufficient, so the ink of the handwriting was severe.

  In Comparative Example 5, since the surface tension at 20 ° C. exceeded 40 mN / m, the wettability was insufficient and the ink repelling of the handwriting was severe. In Comparative Example 6, since the surface tension at 20 ° C. was less than 20 mN / m, bleeding was severe.

  The present invention relates to a water-based ink composition for a writing instrument, and more specifically, a water-based ink composition for a writing instrument containing at least water, a colorant, a dry-up inhibitor, and a surfactant, The solubility in water at 20 ° C. is 3.0 to 20.0 mass%, and the surface tension at 20 ° C. of the aqueous ink composition for writing instruments is 20 to 40 mN / m, A water-based ink composition for a writing instrument that is excellent in dry-up performance and can be written on a non-penetrating surface can be provided. Moreover, it can be used suitably not only for the marking pen of an Example but a ball-point pen, a fountain pen, a sign pen, a plate pen, etc. Furthermore, it can utilize widely as writing instruments, such as a cap type and a knock type.

Claims (5)

A water-based ink composition for a writing instrument containing at least water, a colorant, a dry-up inhibitor, and a surfactant, wherein the solubility of the dry-up inhibitor in water at 20 ° C. is 3.0 to 20.0 mass. %, And the surface tension at 20 ° C. of the water-based ink composition for a writing instrument is 20 to 40 mN / m. The water-based ink composition for a writing instrument according to claim 1, wherein the dry-up inhibitor is a higher alcohol-based dry-up inhibitor. The water-based ink composition for a writing instrument according to claim 1 or 2, wherein the content of the dry-up inhibitor is 0.1 to 20.0 mass% with respect to the content of water at 20 ° C. object. The said surfactant contains 1 or more types chosen from a silicon-type surfactant, an acetylene glycol-type surfactant, a fluorine-type surfactant, and a dialkyl sulfo succinate, The Claim 1 thru | or 3 characterized by the above-mentioned. Water-based ink composition for writing instruments. 5. The water-based ink composition for a writing instrument according to claim 1, wherein the surfactant is a polyether-modified silicone oil having a content of 0.01 to 5.00% by mass.