JP6324867B2 - Water-based ink composition for marking pen and direct liquid type marking pen - Google Patents

Description

  The present invention relates to a water-based ink composition for a marking pen and a direct liquid marking pen.

  Conventionally, as a water-based ink composition for drawing a writing line having glitter, a water-based ink composition for ballpoint pens containing a glitter pigment (for example, Patent Documents 1 to 3), a water-based ink composition for marking pens (for example, Patent Document 4) and the like are known.

Patent No. 4,240,459 Japanese Patent No. 3774546 Japanese Patent No. 4232932 Japanese Patent No. 4822600

  In order to give glitter or concealment to the writing line, when an inorganic pigment is included in the ink composition as a glitter pigment or a concealing pigment, the inorganic pigment has a high specific gravity. There is a problem that sedimentation of the pigment occurs. If the inorganic pigment settles in the ink composition, the inorganic pigment may not be discharged sufficiently during writing, or the high concentration of inorganic pigment may be discharged. Therefore, color unevenness or density unevenness occurs, and desired glitter or concealment cannot be stably obtained. On the other hand, if it is attempted to suppress sedimentation of the inorganic pigment by increasing the viscosity of the ink composition, the dischargeability of the ink composition itself from the pen tip deteriorates, resulting in poor writing.

  An object of the present invention is to provide a water-based ink composition for a marking pen that suppresses sedimentation of an inorganic pigment and has a good ink discharging property, and a direct liquid marking pen using the same.

  The present invention includes water, an inorganic pigment, fermented cellulose, and a polymer material excluding fermented cellulose, and is measured using an E-type viscometer at 25 ° C., 0.8 ° × R24 rotor, 6 rpm. A water-based ink composition for a marking pen having a viscosity of 15 to 50 mPa · s.

  The water-based ink composition for a marking pen according to the present invention is excellent in ink discharge properties when the viscosity is in the above range. Further, in the case of a conventional water-based ink composition for a marking pen, an inorganic pigment tends to settle when the viscosity is such a low value, but the water-based ink composition for a marking pen of the present invention has a viscosity of 15 mPa · s. By including fermented cellulose and a high-molecular substance excluding fermented cellulose as described above, sedimentation of the inorganic pigment can be suppressed.

  The inorganic pigment can be at least one selected from the group consisting of a metal-coated flaky glass pigment, a metal oxide-coated flaky glass pigment, a metal powder pigment, a metal oxide powder pigment, and a pearl pigment. The average particle size of the inorganic pigment is preferably 100 μm or less.

  The water-based ink composition for a marking pen may further contain an antifoaming agent.

  The present invention also provides a direct liquid type marking pen comprising a pen tip and an ink storage unit, wherein the water base ink composition for the marking pen is stored in the ink storage unit.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based ink composition for marking pens which an inorganic pigment cannot settle easily, and is excellent in ink discharge | emission property, and a direct liquid type marking pen using the same can be provided.

FIG. 1 is a cross-sectional view of a direct liquid marking pen according to an embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary.

(Water-based ink composition for marking pens)
The water-based ink composition for a marking pen according to the present embodiment (hereinafter also simply referred to as “water-based ink composition”) includes water, an inorganic pigment, fermented cellulose, and a high-molecular substance excluding fermented cellulose. The water-based ink composition has a viscosity of 15 to 50 mPa · s measured using an E-type viscometer under the conditions of 25 ° C., 0.8 ° × R24 rotor, 6 rpm.

  When drawn as a writing line, the inorganic pigment reflects light and exhibits glitter or exhibits concealment. The average particle diameter of the inorganic pigment is preferably 100 μm or less, and more preferably 50 μm or less, from the viewpoint of ink discharge performance in the tip of the marking pen. Further, the average particle diameter of the inorganic pigment is preferably 0.1 μm or more in order to impart sufficient glitter to the writing line or to obtain sufficient visibility of the inorganic pigment on the writing line. More preferably. The average particle diameter of the inorganic pigment can be measured by a laser diffraction particle size distribution measurement method on a volume basis.

  The inorganic pigment may be plate-shaped. It is preferable to use a plate-like inorganic pigment because it is excellent in glitter. When the inorganic pigment is plate-like, the average thickness of the inorganic pigment is preferably 0.02 to 3 μm, more preferably 0.05 to 3 μm, and still more preferably 0.2 to 2 μm. . Further, the plate-like inorganic pigment preferably has an average particle diameter / average thickness ratio (aspect ratio) of 5 to 80, and more preferably 10 to 50. When the aspect ratio is in the above range, a writing line having good glitter can be obtained. The average thickness of the plate-like inorganic pigment is an average value obtained by measuring the thickness of the inorganic pigment by 10 or more using an electron microscope and dividing the total value by the number of measurement.

  The specific gravity of the inorganic pigment is preferably 6 or less, and more preferably 5 or less. Since the water-based ink composition according to this embodiment can suppress sedimentation of inorganic pigments, even if an inorganic pigment having a large specific gravity is used, a writing line having glitter or concealment can be stabilized without color unevenness or density unevenness. Can be drawn. The specific gravity of the inorganic pigment is usually 1 or more, and the closer to 1, the more excellent the precipitation resistance.

  The content of the inorganic pigment in the water-based ink composition is a solid content based on the total amount of the water-based ink composition, preferably 0.1 to 15% by mass, more preferably 0.5 to 8% by mass, More preferably, it is 0.5-4 mass%. The content of the inorganic pigment is preferably in the above range from the viewpoints of the visibility of the inorganic pigment on the writing line and the ink discharge property. The inorganic pigment may be used as it is, or may be used as a dispersion, paste or the like dispersed in water, a solvent such as propylene glycol monomethyl ether.

  Examples of the inorganic pigment include a metal-coated flaky glass pigment, a metal oxide-coated flaky glass pigment, a metal powder pigment, a metal oxide powder pigment, and a pearl pigment. When these pigments are used as inorganic pigments, the effects of the present invention are particularly suitably exhibited. Moreover, it is preferable to use these pigments as the inorganic pigment because the writing line is given glitter and a unique design property or concealability is obtained. Among these, a metal-coated flaky glass pigment, a metal oxide-coated flaky glass pigment, a metal powder pigment, or a pearl pigment is suitable as a plate-like inorganic pigment that imparts glitter to a writing line. An inorganic pigment may be used individually by 1 type, and may use 2 or more types together.

  The metal or metal oxide-coated flaky glass pigment is obtained by coating flaky glass with a metal such as gold or silver, or a metal oxide such as titanium oxide. Examples of commercially available products include Metashine ME2040PS (manufactured by Nippon Sheet Glass Co., Ltd.).

  As the metal powder pigment, aluminum powder pigment, copper powder pigment, nickel powder pigment, brass powder pigment, etc. can be used, and as the metal oxide powder pigment, titanium oxide powder pigment, iron oxide pigment, zinc oxide pigment, etc. Can be used. Among these, an aluminum powder pigment or a titanium oxide powder pigment is preferable. Use of a titanium oxide powder pigment is preferable because a writing line with high concealability can be obtained. Examples of commercially available metal powder or metal oxide powder pigment include aluminum paste CS430SWYA (aluminum powder pigment, manufactured by Showa Aluminum Co., Ltd.), micropigmo WMWE-1 (titanium oxide pigment, manufactured by Orient Kogyo Co., Ltd.), and MF-5767 white (titanium oxide pigment). , Manufactured by Dainichi Seika Kogyo Co., Ltd.).

  As the pearl pigment, a flaky mineral inorganic particle such as mica, a flaky metal particle or the like is used as a core material, and the surface of the core material is coated with a metal oxide such as titanium oxide or iron oxide. . The thing in which the color was variously changed by adjusting the film thickness of the metal oxide to coat | cover is marketed. The pearl pigment may be naturally derived from fish scales, fish skins, shellfish and the like. Examples of commercially available pearl pigments include Iriodin (registered trademark) 111 (manufactured by Merck Japan), Pearl Glaze (registered trademark) MF-100 (manufactured by Nippon Koken Kogyo), and the like.

  Fermented cellulose is cellulose (β-1,4 glucan) produced by fermenting cellulose-producing bacteria using starch raw materials such as corn. General cellulose fibers obtained from wood or the like usually have a fiber diameter of 15 to 30 μm, whereas fermented cellulose is characterized by a very thin fiber diameter of 0.1 to 0.2 μm. Fermented cellulose is considered to exhibit an excellent solid dispersion ability by forming a three-dimensional network structure with very fine fibers that are insoluble in water in water. Examples of cellulose-producing bacteria include bacteria belonging to the genus Acetobacter, Pseudomonas, Agrobacterium, and the like. Among them, fermented cellulose produced by a cellulose-producing bacterium (acetic acid bacterium) belonging to the genus Acetobacter is preferable, and fermented cellulose produced by an Acetobacter xylinum strain is more preferable.

  The fermented cellulose content in the water-based ink composition is a solid content based on the total amount of the water-based ink composition, and is preferably 0.027 to 0.090% by mass. It is preferable that the content of fermented cellulose in the water-based ink composition is 0.027% by mass or more because precipitation of the inorganic pigment can be more effectively suppressed. On the other hand, it is preferable that the content of fermented cellulose in the water-based ink composition is 0.090% by mass or less because an excessive increase in viscosity of the water-based ink composition is suppressed and ink discharge from the marking pen tip becomes better. . The fermented cellulose content in the water-based ink composition is more preferably 0.03 to 0.08% by mass.

  Examples of the polymer substance include xanthan gum, galactomannan (guar gum, locust bean gum, tara gum, etc.), carrageenan, glucomannan, native gellan gum, deacylated gellan gum, pectin, alginates (alginate, alginate), curdlan, Pullulan, water-soluble hemicellulose, soybean polysaccharide, natural starch such as processed starch, raw starch, methylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose or salts thereof, cellulose derivatives such as hydroxypropylcellulose, hydroxyethylcellulose, tamarind seed gum , Cassia gum, tragacanth gum, karaya gum, gum arabic, gati gum, psyllium seed gum, macrohomopsis gum, agar and other natural polysaccharides Molecules, gelatin or the like can be used. A high molecular substance may be used individually by 1 type, and may use 2 or more types together.

  As the polymer substance, xanthan gum, galactomannan, carboxymethylcellulose or a salt thereof is preferably used, and a combination of xanthan gum and carboxymethylcellulose sodium, or a combination of galactomannan and carboxymethylcellulose sodium is more preferable. By using these polymer substances, the aggregation of fermented cellulose in water can be prevented and a higher dispersion effect can be obtained, so that sedimentation of inorganic pigments in the aqueous ink composition can be more efficiently suppressed. .

  The polymer substance is preferably combined with fermented cellulose. By using fermented cellulose combined with a polymer substance, it is possible to further enhance the effect of suppressing the precipitation of inorganic pigments in the aqueous ink composition. As a method of conjugation, for example, a polymer substance may be added at the time of culturing cellulose-producing bacteria, and fermented cellulose may be compounded with a polymer substance. A fermented cellulose gel produced by cellulose-producing bacteria may be used. It may be soaked in a solution of a polymer material and impregnated with the polymer of fermented cellulose to be combined. Fermented cellulose combined with a polymer substance is commercially available as San Artist (registered trademark) H-PN, H-PG, etc. manufactured by San-Ei Gen FFI.

  The content of the polymer substance can be 10 to 200 parts by mass with respect to 100 parts by mass of the fermented cellulose, preferably 30 to 150 parts by mass, and more preferably 60 to 110 parts by mass. It is preferable for the content of the polymer substance to be in the above range since aggregation of the fermented cellulose in water can be prevented, a higher dispersion effect can be obtained, and sedimentation of the inorganic pigment can be more efficiently suppressed.

  The water-based ink composition may further contain a coloring material. The color material is preferably a pigment, more preferably a fluorescent pigment, and still more preferably an organic fluorescent pigment. The organic fluorescent pigment is obtained by coloring resin particles with a fluorescent dye. Examples of the resin particles include acrylic resin particles, styrene acrylonitrile resin particles, and acrylonitrile butadiene resin particles.

  The water-based ink composition for a marking pen according to the present embodiment may further contain an antifoaming agent. By using an antifoaming agent, it is possible to prevent the generation of bubbles during the production of the ink composition, and it is possible to perform stable gas-liquid exchange during writing, and it is possible to suppress blur due to insufficient ink flow. As the antifoaming agent, for example, silicone-based, hydrophobic silica-based, alkit-based, polyether-based, oil-based, metal soap-based, and amide wax-based antifoaming agents can be used. When using an antifoaming agent, it is preferable to use a silicone type antifoaming agent and / or a hydrophobic silica type antifoaming agent from a viewpoint of defoaming property and the effectiveness of gas-liquid exchange.

  In addition to the above-mentioned components, the water-based ink composition of the present embodiment does not impair the effects obtained in the present embodiment, a solvent other than water, a humectant, a rust inhibitor, a pH adjuster, a thickener, Additives such as preservatives (antifungal agents), lubricants, pigment dispersants, and fixing resins may be contained.

  The water-based ink composition of this embodiment can be obtained by mixing the above-described raw materials using, for example, a stirrer such as a dissolver, a Henschel mixer, or a homomixer. The stirring conditions of the stirrer are not particularly limited. For example, by using a dissolver stirrer and stirring at a rotational speed of 5000 to 12000 rpm for 60 to 120 minutes, a water-based ink composition in which each component is uniformly dispersed can be obtained.

  The water-based ink composition obtained as described above preferably has a viscosity of 15 to 50 mPa · s measured using an E-type viscometer under the conditions of 25 ° C., 0.8 ° × R24 rotor, 6 rpm. Is 15 to 40 mPa · s, more preferably 18 to 35 mPa · s. By setting the viscosity of the water-based ink composition in the above range, it is possible to obtain a water-based ink composition excellent in dischargeability from the marking pen, and to suppress sedimentation of the inorganic pigment in the water-based ink composition. .

(Marking pen)
The marking pen of the present embodiment includes a pen tip made of a fiber core or a plastic core and an ink storage unit, and the water-based ink composition is stored in the ink storage unit.

  FIG. 1 is a cross-sectional view of a marking pen according to an embodiment of the present invention. The marking pen 10 in FIG. 1 is a direct liquid type. The marking pen 10 includes an ink storage unit 1, a valve 2, a pen tip 3, a shaft body 4, and a cap (not shown). In the marking pen 10, the gap inside the shaft body 4 serves as the ink storage portion 1, and the water-based ink composition 5 is stored in the ink storage portion 1. In addition to the shaft body 4, a cylindrical center shaft may be provided inside the shaft body 4, and a gap inside the center shaft may be used as the ink containing portion 1. The ink container 1 and the pen tip 3 are connected via a valve 2, and the water-based ink composition 5 in the ink container 1 is supplied to the pen tip 3 via the valve 2.

  The nib 3 is formed of a fiber core or a plastic core that can supply the water-based ink composition 5. When using a fiber core, adjust the porosity of the fiber core, the fiber thread diameter, the amount of impregnation into the core of the water-based ink composition, etc. according to the particle diameter of the inorganic pigment in order to facilitate the discharge of the inorganic pigment. Is preferred. In particular, when an inorganic pigment having a large particle diameter of, for example, 1 μm or more is used as the inorganic pigment, the fiber core preferably has a porosity of 50 to 85%, and the fiber diameter used is 10 to 50 d (denier). ) Is preferable. Similarly, when a plastic core is used, it is preferable to adjust the ink flow path width according to the particle diameter of the inorganic pigment. In the marking pen 10, the tip shape of the pen tip 3 is a chisel shape having an inclined surface inclined with respect to the center line of the shaft body 4. A writing line can be drawn when the inclined surface of the nib 3 contacts the paper surface. At this time, the length of the inclined surface in the longitudinal direction is the line width of the writing line. The length of the inclined surface in the longitudinal direction is preferably 2 mm or more, and more preferably 2 to 5 mm from the viewpoint of easy marking. In the marking pen 10, the tip shape of the pen tip 3 is not limited to the chisel shape, and may be a shell shape, a brush pen shape, or the like.

  There are no particular restrictions on the materials or shapes that make up the valve 2, the shaft body 4, and the cap, and general materials are used as appropriate.

  The water-based ink composition for a marking pen according to this embodiment is preferably used for a direct liquid type marking pen.

  In conventional marking pens for drawing writing lines with brilliant or concealing properties, there are also those that are used after stirring the ink by shaking the main body just before writing, provided with a stirrer such as a ball in the ink container. is there. On the other hand, the water-based ink composition for a marking pen according to the present embodiment has a sufficiently high effect of suppressing the precipitation of the inorganic pigment, so that the inorganic pigment does not easily settle without stirring the ink just before writing. The state can be maintained, and suitable writing properties without color unevenness or density unevenness can be obtained. Accordingly, one of the preferred embodiments is a marking pen that does not include a stirrer in the ink container. The marking pen may include a stirrer in the ink storage unit.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited to these examples.

(Preparation of water-based ink composition for marking pen)
Each material was mixed by the ratio (unit: mass%) shown in Table 1, and the water-based ink composition for marking pens of an Example and a comparative example was obtained.

Details of each material described in Table 1 are as follows.
・ Lumicol mild pink: coloring material (processed pigment), manufactured by Nippon Fluorochemicals, Inc. ・ Glycerin: moisturizer, manufactured by NOF Corporation ・ BY-1383N: fixing resin, manufactured by Toho Chemical Co., Ltd. ・ Slout 99N: preservative, Nippon Enviro Chemicals Production / dispersant (Examples 1 to 3 and Comparative Examples 1 and 2): a composite containing fermented cellulose (50% by mass), sodium carboxymethylcellulose (17% by mass) and xanthan gum (33% by mass), trade name “Sun artist HP-N”, manufactured by San-Ei Gen FFI Co., Ltd., dispersant (Example 2): fermented cellulose (60% by mass), sodium carboxymethylcellulose (20% by mass) and guar gum (20% by mass) Containing compound, trade name “Sun Artist HP-G”, Saneigen FFI Co., Ltd., Dispersant (Comparative Examples 3-7): Xanthan Gum, DSP Gokyo Food & Chemical Co., Ltd. Metashine ME2040PS: Silver-coated flaky glass pigment (plate-like inorganic pigment), aluminoborosilicate glass 70-80 mass%, silver 20-30 mass%. Average particle size 40 μm, average thickness 1 μm, pigment specific gravity 4.6, non-surface treatment (non-water-repellent treatment), manufactured by Nippon Sheet Glass Co., Ltd. ・ Iriodin 111: Pearl pigment (plate-like inorganic pigment), titanium oxide-coated mica, mica 55% by mass, titanium oxide 45% by mass, average particle size 6 μm, average thickness 0.34 μm, pigment specific gravity 3.1, manufactured by Merck Japan, Aluminum paste CS430SWYA: aluminum powder paste pigment (plate-like inorganic pigment), aluminum 65% by mass, propylene glycol monomethyl ether 30% by mass, pigment content 65% by mass, average particle size 9 μm, average thickness 0.27 μm, pigment specific gravity 2.7, manufactured by Showa Aluminum Co., Ltd./Micropigmo WMWE-1: Titanium oxide powder Water dispersion (spherical inorganic pigment), pigment content 35% by mass, average particle size 0.3 μm, pigment specific gravity 4.0, manufactured by Orient Chemical Industries, S N deformer 1316: modified silicone antifoam, manufactured by San Nopco

(Evaluation of water-based ink composition for marking pen)
Each of the water-based ink compositions obtained in Examples and Comparative Examples was filled in the ink storage portion of the valve-type direct liquid marking pen having the structure shown in FIG. 1, and the pen tip was soaked with the water-based ink composition. . A polyester tip (Taiba Co., Ltd.) was used for the nib. A marking pen having a transparent ink container was used so that the ink composition could be observed from the outside. The following evaluation was performed using the obtained marking pen. The results are shown in Table 2.

(Ink discharge evaluation)
Writing was performed using the marking pens obtained in the examples and comparative examples, and the ink dischargeability was evaluated according to the following criteria.
AA: Writing is possible without problems, and the following is very good.
A: Writing is possible without any problem and good followability.
B: Although writing is possible, followability is bad.
C: Writing is impossible.

(Inorganic pigment sedimentation evaluation)
The marking pens obtained in the examples and comparative examples were allowed to stand at room temperature for 7 days with the caps capped and the pen tip upright. During the standing, the inorganic pigment in the water-based ink composition gradually settled, and a layer where no inorganic pigment was observed (an inorganic pigment-free layer) was generated on the liquid surface side. The height (mm) of the inorganic pigment absent layer was measured with respect to the height of about 60 mm from the bottom of the ink containing part to the ink liquid level. The larger the value, the greater the degree of sedimentation.

  In the marking pens obtained in the examples, sedimentation of the inorganic pigment in the water-based ink composition was suppressed, and the ink discharging property was excellent. Moreover, in the marking pen obtained in the Example, the water-based ink composition was uniformly discharged from the pen tip, and a writing line having stable glitter or concealment by the inorganic pigment could be obtained. On the other hand, in the marking pens of Comparative Examples 1 and 3 to 7, remarkable precipitation of the inorganic pigment occurred. Further, in the marking pen of Comparative Example 2, although the sedimentation of the pigment was suppressed, the ink followability was inferior due to the high viscosity.

  DESCRIPTION OF SYMBOLS 1 ... Ink storage part, 2 ... Valve | bulb, 3 ... Pen tip, 4 ... Shaft body, 5 ... Water-based ink composition, 10 ... Marking pen.

Claims (4)

  It contains water, an inorganic pigment, fermented cellulose, and a high-molecular substance excluding fermented cellulose, and has a viscosity measured by using an E-type viscometer at 25 ° C., 0.8 ° × R24 rotor, 6 rpm. A water-based ink composition for a marking pen, which is ˜50 mPa · s.   The inorganic pigment is at least one selected from the group consisting of a metal-coated flaky glass pigment, a metal oxide-coated flaky glass pigment, a metal powder pigment, a metal oxide powder pigment, and a pearl pigment, and has an average particle size. The water-based ink composition for a marking pen according to claim 1, which is 100 µm or less.   The water-based ink composition for a marking pen according to claim 1 or 2, further comprising an antifoaming agent. It is a direct liquid type marking pen provided with a nib and an ink container,
The direct liquid type marking pen which accommodates the water-based ink composition for marking pens as described in any one of Claims 1-3 in the said ink accommodating part.

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