JP4549044B2 - Dye ink composition for aqueous ballpoint pen - Google Patents

Description

  The present invention relates to a dye ink composition for water-based ballpoint pens, and in particular, the ink composition is filled in an ink storage tube in which a liquid agent called a liquid stopper at the rear end is disposed as an ink follower, and an ink guide core or pen The present invention relates to an ink composition suitable for a directly-connected type water-based ballpoint pen that is directly supplied to a ballpoint pen tip without using a lead, and more specifically, facilitates the determination of the color of the filled ink dye from the appearance of the ink storage tube, In addition, the present invention relates to a dye ball ink composition for water-based ballpoint pens that is excellent in writability, has no clogging of the pen tip even when stored for a long time, and has excellent temporal stability.

  Conventionally, as dye inks for water-based ballpoint pens, those containing a dye as a colorant and a water-soluble organic solvent or water as a solvent are generally used. Even if the color of the filled ink dye from the appearance is originally an ink such as blue, red, and green, the appearance color is dark black, and it is difficult to distinguish the original ink dye color. For the visibility of the appearance of the ink storage tube in such dye ink, by adding white resin particles, the visual color on the external appearance of the ink storage tube of the direct liquid water-based ballpoint pen and the visual color of the drawn line on the blank paper are approximately approximated. In the past, attempts have been made to improve the above-mentioned drawbacks by adding a titanium oxide (see, for example, Patent Document 1). However, in the case of the above-mentioned white resin particles, visibility cannot be obtained unless the addition amount is increased to 5% by weight or more in terms of solid content, and there is a problem that clogging due to sedimentation or dry-up occurs. It was.

In recent years, a ballpoint pen for a fine ball having a ball diameter of 0.38 mmφ or less, and an extra-fine character having a ball diameter of 0.28 mmφ or less is also demanded from the market. In addition, there is a problem that the dry-up tends to occur remarkably. In addition, it has been proposed to add fine powdered silicon dioxide and alumina together as a thickener to the ink of a direct-coupled water-based ballpoint pen (see, for example, Patent Document 2). In order to improve the viscosity of the fine powder as a thickener, the primary particle diameter is 7 to about 40 nm. It is not possible to obtain a sufficient effect on visibility on the appearance.
Japanese Patent Laid-Open No. 11-12526 JP-A-7-76665

  In view of the above-mentioned problems, the object of the present invention is excellent in the color visibility on the appearance of the dye ink filled in the ink storage tube, and in particular, writing in an aqueous ballpoint pen for fine letters with a ball diameter of 0.38 mmφ or less. It is intended to provide a dye ink composition having excellent stability over time without causing clogging of the pen tip during long-term storage and without causing dry-up.

The present inventors can visually recognize the color of the filled ink dye from the appearance of the ink storage tube by mixing silica or alumina fine particles having a specific average particle size in combination with a thickener in the dye ink. It has been found that the above problems can be solved by improving the properties, and the present invention has been completed. That is, the present invention
(1) Silica having an average particle size of 0.05 to 2 μm in combination with a thickener in a dye ink composition containing at least a dye as a colorant, water, a water-soluble organic solvent , and a phosphate ester alkyl ether A dye ink composition for water-based ballpoint pens, which is used in fine ballpoint pens having a ball diameter of 0.38 mm or less, comprising white fine particles of alumina.
(2) The dye ink composition for an aqueous ballpoint pen according to claim 1, wherein the viscosity at 1 rpm measured by an E-type rotational viscometer is 200 to 5000 mPa · s (25 ° C.).
(3) A thin ballpoint pen having a ball diameter of 0.38 mm or less on which the dye ink composition for an aqueous ballpoint pen according to claim 1 or 2 is mounted .

  According to the water-based ink composition of the present invention, the added alumina and silica fine particles are white fine particles. When the ink storage tube is filled, the color of the ink dye is clearly set against the background of the white fine particles. It is thought to make it easier to distinguish from the appearance and color discrimination. In addition, when used for fine ballpoint pens with a ball diameter of 0.38 mm or less, especially 0.18 to 0.28 mm extra fine ballpoint pens, the fine particles of alumina and silica also have an effect on the wear resistance of the ballpoint pen tip. By maintaining the ink viscosity of this, clogging due to sedimentation and dry-up do not occur, and writing feeling, ink outflow property, and stability over time are not impaired.

  Hereinafter, the best mode for carrying out the present invention will be described in detail. In the present invention, silica or alumina that is white fine particles contained in an ink composition containing at least water, a colorant, and a water-soluble solvent needs to have an average particle diameter of 0.05 to 2 μm. If the average particle diameter of silica or alumina is less than 0.05 μm, there is a possibility that a sufficient effect on the visibility may not be obtained, and if it exceeds 2 μm, the writing feeling is deteriorated, the outflow property is deteriorated, and also due to sedimentation. Clogging occurs and writing becomes impossible. The average particle diameter of the fine particles is preferably 0.05 to 1 μm. The addition amount of the silica or alumina fine particles is preferably in the range of 0.1 to 5% by weight with respect to the total amount of the ink. If it is 0.1% by weight or less, the effect of visibility is not obtained, and if it is 5% by weight or more, writing defects such as blurring may occur, which is not preferable in terms of writing property.

  The alumina and silica fine particles are white fine particles, and the shape is preferably spherical in order to improve visibility and writing feeling. As the alumina preferably used, high-purity alumina AKR-3000 (particle diameter 0.5 μm) manufactured by Sumitomo Chemical Co., Ltd., HARIMICA X1-125 (particle diameter 1.2 μm) manufactured by Micron, Admafine AO-802 manufactured by Admatex (particle diameter) 0.7 [mu] m), Tymicron TM-10 (particle size 0.1 [mu] m) manufactured by Daimei Chemical. Examples of silica include Admafine Admafine SO-C1 (particle diameter 0.2 μm) and SO-C2 (particle diameter 0.5 μm).

  In improving the temporal stability of the fine particles, aggregation and sedimentation can be suppressed by adding a dispersant, and nonionic, anionic surfactants and water-soluble resins are used as the dispersant. Preferably, it is a water-soluble resin. For example, synthetic water-soluble polymers such as polyvinyl alcohol, polyacrylic acid, acrylic acid copolymer, maleic acid resin, polyvinyl pyrrolidone, polyethylene oxide, water-soluble acrylic resin, and water-soluble styrene-acrylic resin. And water dispersible emulsions such as acrylic resin, alkyd resin, vinyl resin, polyester resin, styrene resin, maleic acid resin, and urethane resin.

  The water-soluble solvent is used for various purposes as an ink, for example, for the purpose of preventing ink freezing at low temperatures and preventing ink drying at the pen tip. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 3-butylene glycol, thiodiethylene glycol, glycerin and other glycols, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, used alone or in combination can do. The amount used is 5 to 50% by weight, preferably 10 to 30% by weight, in the ink composition.

  As the colorant, any of water-soluble dyes conventionally used in water-based ink compositions can be used. In addition, inorganic pigments, organic pigments, and pseudo pigments can also be blended to such an extent that they do not have an adverse effect. As the water-soluble dye, any of a direct dye, an acid dye, a food dye, and a basic dye can be used. An example of a direct dye is described below. C. I. Direct Black 17, 19, 19, 22, 32, 38, 51, 71, C.I. I. Direct yellow 4, 26, 44, 50, C.I. I. Direct Red 1, 4, 23, 31, 37, 39, 75, 80, 81, 83, 225, 226, 227, C.I. I. Dileg Blue 1, 15, 71, 86, 106, 119 and the like.

  An example of an acid dye is described below. C. I. Acid Black 1, 2, 24, 26, 31, 31, 52, 107, 109, 110, 119, 154, C.I. I. Acid Yellow 7, 17, 19, 23, 25, 29, 38, 42, 49, 61, 72, 78, 110, 141, 127, 135, 142, C.I. I. Acid Red 8, 9, 9, 14, 26, 27, 35, 37, 51, 52, 57, 82, 87, 92, 94, 115, 129, 131, 186, 249, 254, 265, 276, C.I. I. Acid Violet 18, 17 and C.I. I. Acid Blue 1, 7, 9, 22, 23, 25, 40, 41, 43, 62, 78, 83, 90, 93, 103, 112, the same 113, 158, C.I. I. Acid Green 3, 9, 16, 25, 27 and the like.

  Food dyes are mostly included in direct dyes or acid dyes, but examples of those that are not included include C.I. I. Food yellow 3 is mentioned. An example of a basic dye is described below. C. I. Basic Yellow 1, 2 and 21, C.I. I. Basic Orange 2, 14, 32, C.I. I. Basic Red 1, 2, 9, 9, 14 C.I. I. Basic Brown 12, Basic Black 2, 8 and the like.

  These colorants may be used alone or in combination of two or more, and the content in the whole composition is usually 0.5 to 30% by weight, preferably 1 to 15% by weight. It is a range. When stored over 30% by weight for a long time, the dye precipitates and clogs the nib, causing poor writing. If it is less than 0.5% by weight, the coloring becomes weak and the hue of the handwriting becomes unclear.

  The thickener is for the purpose of increasing the viscosity of the ink composition in order to suppress sedimentation of fine particles, and known thickeners can be used. For example, at least one selected from the group consisting of synthetic polymers, natural rubber, cellulose and polysaccharides. More specifically, for example, gum arabic, gum tragacanth, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, xanthan gum, dextran, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, sodium starch glycolate, propylene glycol alginate, Polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, copolymer of vinyl acetate and polyvinyl pyrrolidone, cross-linked acrylic acid polymer, salt of styrene acrylic acid copolymer, etc. It is done. The content is preferably 0.1 to 0.6% by weight, more preferably 0.1 to 0.4% by weight, based on the total amount of the ink composition.

  The viscosity of the ink composition of the present invention (viscosity at 25 ° C. at 1 rpm by an E-type rotational viscometer) is preferably 200 to 5000 mPa · s. Here, if the viscosity is less than 200 mPa · s, there is a high possibility that the silica or alumina fine particles are clogged due to sedimentation. On the other hand, when the viscosity is 5000 mPa · s or more, the outflow of ink from the pen tip becomes worse. Preferably, the viscosity is 500 to 2000 mPa · s.

  Further, in a normal aqueous dye ink composition, writing defects due to dry-up are particularly noticeable with a ballpoint pen having a ball diameter of less than 0.5 mm. However, the ink composition according to (1) or (2) of the present invention described above. As a product, even a thin ballpoint pen having a ball diameter of 0.38 mm or less has good non-drying properties and stability over time.

  If necessary, a lubricant, a rust inhibitor, a pH adjuster, an antiseptic / antibacterial agent, and the like may be added to the aqueous dye ink composition of the present invention. Non-ionic lubricants such as fatty acid esters of polyhydric alcohols, higher fatty acid esters of sugars, polyoxyalkylene higher fatty acid esters, alkyl phosphoric acid esters, etc., and higher fatty acid amide alkyl sulfonates also used as pigment surface treatment agents And anionic compounds such as alkyl allyl sulfonates, polyalkylene glycol derivatives, fluorine surfactants, polyether-modified silicones, and the like. Rust prevention percent is benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, saponins, etc., and PH adjusters are ammonia, urea, triethanolamine, aminomethyl propanol, sodium hydroxide, etc. Examples of the agent include phenol, sodium omadin, sodium benzoate, and benzimidazole compounds.

  In order to produce the water-based ink composition of the present invention, conventionally known methods can be employed, for example, by blending predetermined amounts of each of the above components and stirring and mixing with a stirrer such as a homomixer or a disper. can get. Further, if necessary, coarse particles in the ink composition may be removed by filtration or centrifugation.

Examples 1-6, Comparative Examples 1-6
The following blending components 1 to 12 were combined, and water-based ink compositions corresponding to Examples and Comparative Examples corresponding to uniform solutions using a stirrer with blending amounts (% by weight) shown in Tables 1 and 2 were prepared. . Table 1 shows the compositions of the example inks, and Table 2 shows the compositions of the comparative inks. Of the example inks, Example 4 shows an example with a relatively large ball diameter, Example 5 shows an example with a relatively high viscosity, and Example 6 shows an example with a relatively low viscosity. Comparative Example 1 has no added particles, Comparative Example 2 has no thickener added, Comparative Example 3 has an excessively large particle size, Comparative Example 4 has a different particle material, and Comparative Example 5 has a different particle material. The example is different and the ball diameter is relatively large.

However, the detail of the mixing | blending component in Table 1 and Table 2 is as follows.
1-a. Coloring agent Blue No. 1 1-b. Red No. 103 1-c. Yellow No. 5 2-a. Shear thinning agent xanthan gum 2-b. Crosslinked polyacrylic acid 3-a. Water-soluble organic solvent Glycerin 3-b. Propylene glycol 4 lubricant Phosphoric acid ester alkyl ether (Toho Chemical: Phosphanol RS-610)
5 Anticorrosive agent Bensotriazole 6 Preservative 1,2-Benzisothiazolin-3-one 7 PH adjuster Triethanolamine 8-a. Alumina TAIMICRON TM-10 (average particle size 0.1 μm)
8-b. Admatech Admafine A0-802 (average particle size 0.7μm)
8-c. AX1-125 manufactured by Micron (average particle size 1.25 μm)
8-d. AX3-32 made by Micron (average particle size 3.5μm)
9 Silica Admatechs Admafine SO-Cl (average particle size 0.2 μm)
10 White resin particles Low bake OP-84J (average particle size 0.55 μm, solid content 42.5%) manufactured by Rohm and Haas
11 Water-soluble resin (styrene acrylate) manufactured by Johnson Polymer: Jonkrill 61J (solid content 30%)
12 Purified water

  Each aqueous ink composition obtained in a tube (PP tube having an inner diameter of 3.4 mm and a PP joint member to the ballpoint pen tip) mounted with a ballpoint pen tip of each ball diameter used for UM-151 manufactured by Mitsubishi Pencil. The ink follower was filled, defoamed by centrifugation (acceleration 500 G, centrifugation time 5 minutes), assembled into a ballpoint pen, and then subjected to various writing tests (A) to (E) shown below. In the writing test, all five ballpoint pens were evaluated.

(A) Visibility: A PP tube is filled with ink, and the appearance is determined according to the following criteria.
(◎: good, ○: generally good, △: slightly difficult to distinguish, ×: difficult to distinguish)
(B) Written feeling test: Written feeling is judged based on the following criteria for sensory evaluation by circular writing with a diameter of 2 cm.
(◎: Smooth, ○: Affordable, △: Caught, ×: Bad)
(C) Non-drying property: After standing for 2 weeks at room temperature in a cap-off state, check with the following criteria by circular writing spiral writing.
(◎: Can be written without any problems from the beginning, ○: Slightly scratched but returned within 2 rounds of the circular writing spiral, △: Returned after 3-10 rounds of circular writing spiral, x: Over 10 rounds of circular writing spiral Scratch occurs)
(D) Centrifugal resistance: After centrifuging with a centrifuge (acceleration 2000 G, centrifugation time 10 min), the writing property is confirmed by a circular spiral based on the following criteria.
(◎: Can be written without any problems from the beginning, ○: Slightly scratched but returned within 2 rounds of the circular writing spiral, △: Returned after 3-10 rounds of circular writing spiral, x: Over 10 rounds of circular writing spiral Scratch occurs)
(E) Writability over time: 50 ° C. After standing downward for 2 weeks, confirm with the following criteria by a circular spiral.
(◎ Can be written without any problems from the beginning, ○: Slight blurring occurs within 2 rounds of the round writing spiral, △: Scratching returns after 10 rounds of the round writing spiral, ×: Scratching occurs over 20 rounds of the circular writing spiral)
These evaluation results are summarized in Table 3.

  From the evaluation results of Table 3, the water-based ink composition satisfying the conditions of the present invention is particularly excellent in the visibility of the appearance in which the PP tube in a fine ball pen with a ball diameter of 0.38 mm or less is packed, Good results have been obtained in terms of writing feeling, non-drying property, centrifugal resistance, writing properties with time, and the like. On the other hand, in the case of the comparative example that does not satisfy the conditions of the present invention, any of the above physical properties is undesirable.

Claims (3)

Silica or alumina white having an average particle size of 0.05 to 2 μm in combination with a thickener in a dye ink composition containing at least a dye as a colorant, water, a water-soluble organic solvent , and a phosphate ester alkyl ether A dye ink composition for water-based ballpoint pens, which is used for fine ballpoint pens containing fine particles and having a ball diameter of 0.38 mm or less .   The dye ink composition for water-based ballpoint pens according to claim 1, wherein the viscosity at 1 rpm by an E-type rotational viscometer is 200 to 5000 mPa · s (25 ° C). A fine ballpoint pen having a ball diameter of 0.38 mm or less, on which the dye ink composition for water-based ballpoint pens according to claim 1 or 2 is mounted.