JP5926132B2 - Aqueous pigment ink composition and aqueous pigment ink writing instrument - Google Patents

Description

  The present invention relates to a white aqueous pigment ink composition and a writing instrument using the composition.

Marking pens for textiles such as cloth have been known for a long time, but the fabric colors of the textiles are diverse, and depending on the color, the marking pen ink does not have sufficient concealment, so the handwriting is not good. Characters oozed by seeping through or penetrating into the fiber product, and with it, it was not possible to exhibit sufficient concealment. In particular, when a pigment having a small particle size is used, the tendency is remarkable.
Patent Document 1 discloses a water-based white ink composition for ballpoint pens containing water, a shear thinning agent, and a pearl pigment having a particle size of 2 to 40 μm whose surface is coated with titanium oxide as a colorant. It is well known. However, since this ink composition is for ballpoint pens, it has a higher viscosity than the marking pen ink and the amount of ink outflow from the tip for ballpoint pen is small. Since it does not rest on the cloth, the visibility is poor.
Further, as described in Patent Document 2, an aqueous pigment ink composition containing a hiding pigment particle having a median diameter of 20 μm or more and a water-soluble adhesive resin is known. Is intended for scratching and scraping with coins after use on paper or the like, and is not an ink composition for so-called writing instruments that is not intended to be scraped off.

JP 2000-119579 A Japanese Patent Laid-Open No. 2005-298761

In the past, when writing with ink on a material having high liquid absorbency such as cloth, the ink composition for a writing instrument penetrates into the material at the handwriting location. As a result, the handwriting smears, the visibility is insufficient due to the colorant penetrating into the material, etc., and the lack of adhesion to the material causes problems such as insufficient washing resistance. It was.
In order to improve this problem, when using a highly viscous ink composition that prevents penetration into the fabric, the pigment clogs at the pen tip of the writing instrument, and the fluidity is insufficient due to the high viscosity. It was difficult to take out the amount of ink composition required for writing from the nib onto a cloth or the like.

1. Titanium dioxide pigment and pearl mica pigment and / or mica pigment are contained in a weight ratio of titanium dioxide pigment: pearl mica pigment and / or mica pigment in the range of 1: 9 to 3: 7, and glass transition A resin emulsion having a temperature (Tg) of −5 ° C. or less, a surface tension of 35 mN / m or more, a viscosity at a shear rate of 1 (1 / s) of 80 to 450 mPa · s, and a shear rate of 1000 (1 / s ) Is a water-based pigment ink composition having a viscosity of 10 to 30 mPa · s.
2. 2. The aqueous pigment ink composition according to 1, wherein the pearl mica pigment and / or the mica pigment has a particle size accumulation of 90% or more with a particle size of 20 μm or less.
3. 3. The aqueous pigment ink composition according to either 1 or 2, wherein the resin emulsion having a glass transition temperature (Tg) of −5 ° C. or lower is an acrylic resin emulsion.
4. A marking pen obtained by storing the aqueous pigment ink composition according to any one of 1 to 3 in an ink storage unit.
5. 5. The marking pen according to 4, wherein the yarn constituting the tip has a yarn diameter of 10 to 30 denier.
6). The marking pen according to 4 or 5, which is used for writing on a liquid-absorbing surface such as cloth.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based pigment ink composition which can form the white handwriting which was clear and excellent in visibility and washing | cleaning resistance also with respect to raw materials with high liquid absorptivity, such as cloth, can be provided.

The action of the aqueous pigment ink composition of the present invention further includes a titanium dioxide pigment, a pearl mica pigment and / or a mica pigment in a specific ratio, and a resin emulsion having a specific glass transition temperature. When the water-based pigment ink composition is used for writing on a dark cloth such as black (hereinafter, simply referred to as a black cloth) by exhibiting a specific viscosity at a shear stress of The penetration of the pigment into the cloth is suppressed.
Furthermore, a titanium dioxide pigment having a particle size of 1 μm or less when the cumulative particle size is 95% in the aqueous pigment ink composition, a pearl mica pigment and / or mica having a particle size accumulation of 90% or more and 20 μm or less. By containing pigments, the penetration of these pigments into the fabric is further suppressed. In the present invention, the cumulative particle size of these pigments indicates the particle size in a volume accumulated at a specific ratio when the particles are accumulated in order from the smallest particle size.
As a means for measuring the cumulative particle size, Microtrac MT3000II (Nikkiso Co., Ltd.) was used as a measuring device, the transmitted light was measured, the particle refractive index was 1.81, and the solvent was water. Then, when the sample is dripped little by little into the apparatus containing the solvent and within the range of the optimum measured concentration, OK is displayed on the PC screen. Thereafter, the measurement button is pressed, and the solvent in which the sample is dispersed is circulated through the cell in the apparatus, and the particle diameter is measured in the cell.
Specifically, the pearl mica pigment and / or mica pigment in the aqueous pigment ink composition adheres to the black cloth so as to close the texture of the black cloth, and the titanium dioxide pigment is deposited thereon. In this way, the titanium dioxide pigment and the pearl mica pigment and / or the mica pigment are prevented from penetrating into the black cloth.
In this way, the handwriting formed on the black cloth to which these pigments are attached has a white color due to the titanium dioxide pigment. However, it does not necessarily exhibit the original white color of titanium dioxide pigments, and may have a color that is similar to the white color of titanium dioxide pigments added by pearl mica pigments and / or mica pigments and other pigments. There is.
Furthermore, since the water-based pigment ink composition of the present invention contains a resin emulsion having a specific glass transition temperature, it is particularly excellent in washing resistance, and the writing part does not fall by washing.

[Titanium dioxide pigment]
Titanium dioxide blended in the ink composition of the present invention is contained in order to improve the concealability as an aqueous pigment ink composition and to obtain a white ink. Titanium pigments can be employed.

[Pearl mica pigment and / or mica pigment]
The pearl mica pigment is a pigment obtained by forming one or more layers made of titanium oxide, silicon oxide, aluminum oxide, iron oxide, etc. on the surface of the mica powder to impart pearly luster, etc. Is a mica pigment generally used as a pigment. As the pearl mica pigment, Iriodin 123 (Merck) or the like can be used.
In the present invention, the reason why such a pigment is used in combination with titanium dioxide particles is that, when an ink composition is used as a material such as a cloth, the pores and fiber gaps of the material are flat plate-like pearl mica pigments. When the mica pigment is buried and the titanium dioxide pigment is placed on the ink composition, the ink composition is not transferred to the material such as cloth, and the white handwriting is caused by the presence of titanium dioxide on the surface of the handwriting. Can be visually observed.
Therefore, the pearl mica pigment and mica pigment to be used are not darkly colored so as to greatly impair the white color of the titanium dioxide pigment, and when these pigments are deposited in order of decreasing particle size, the particle size is 20 μm or less. The pigment content is high, and the cumulative particle size is 90% or more, preferably 95% or more.

When there are many pearl mica pigments having a particle size of more than 20 μm in the aqueous pigment ink composition, the pearl mica pigment and / or mica pigment is clogged in the tip of the writing instrument as in the case of the titanium dioxide pigment. It becomes easier and there is a higher possibility that writing cannot be performed stably. In addition, there is a possibility that the ink settles and separates in the tank containing the ink.
Moreover, you may make the average particle diameter of a pearl mica pigment and a mica pigment larger than the average particle diameter of a titanium dioxide pigment from the point which prevents a titanium dioxide pigment permeating into cloth.
However, even if it is a pearl mica pigment, a pigment having a colored layer such as an iron oxide layer or an originally colored mica pigment is colored by these pigments themselves, so even if a titanium dioxide pigment is used in combination, the handwriting is white. However, as described above, it can be used as long as the white coloration by titanium dioxide is not significantly impaired.

As such a pearl mica pigment, for example, Iriodin 123 or 111 can be used, and as a mica pigment, for example, TM-10 made by Yamaguchi Mica can be used.
The pearl mica pigment and mica pigment used in the present invention cannot be blended into the ink composition in an untreated state because of the special particle size distribution. These pigments can be used only after they are pulverized to reduce the particle size before use and classified to remove coarse particles having a particle size exceeding 20 μm.
The same can be said for the titanium dioxide particles with respect to such treatment, and the particles are adjusted so as to fall within the above-mentioned particle size range by pulverization or the like as necessary.

[Ratio of content of titanium dioxide pigment and pearl mica pigment and / or mica pigment]
In the ink composition of the present invention, the titanium dioxide pigment and the pearl mica pigment and / or mica pigment are contained in a weight ratio in the range of 1: 9 to 3: 7, preferably 1.5: 8.5 to 2.2. It is contained at a weight ratio of 5: 7.5. If the ratio of the titanium dioxide pigment is out of the range of the ratio of these pigments and the ratio of the pearl mica pigment and the mica pigment for controlling the penetration of the ink composition into the material such as the cloth becomes low, There is a high possibility that setback occurs due to the penetration of the titanium dioxide pigment into the back side of the material. Conversely, if the ratio of the titanium dioxide pigment is too low, the amount of titanium dioxide pigment present on the handwriting will decrease, so the handwriting will not be white and the luster of the pearl mica pigment or mica pigment may be too strong. .
The total content of titanium dioxide pigment and pearl mica pigment and / or mica pigment is 5.0 to 60.0% by weight, preferably 10.0 to 40.0%, based on the ink composition. If it exceeds 60.0% by weight, the viscosity of the ink composition becomes too high and the outflow property of the ink is deteriorated. If it is less than 5.0% by weight, the color developability of the ink composition is inferior and the concealing property is also deteriorated. become.

[Dispersion resin]
The ink composition of the present invention is a water-based ink and may contain a dispersion resin in order to improve the dispersibility of the pigment. As such a dispersion resin, resins such as styrene / acrylic resins such as Joncrill J-62 and styrene / maleic acid copolymers are preferably used, but are not limited thereto. The resin used is excellent in solubility in water and has the effect of preventing pigment precipitation by stabilizing the pigment after dispersion, and at the same time, a vehicle for forming a coating film of an aqueous pigment ink composition Function as.

[Resin emulsion]
As the resin emulsion of the present invention, an acrylic resin emulsion such as Boncoat AB-886 can be used.
The resin dispersed in these emulsions preferably has a Tg of −5 ° C. or lower, more preferably −10 ° C. or lower, more preferably −15 ° C. or lower. By using such a Tg resin, adhesion to the material is improved during writing.
The resin emulsion contained in the aqueous pigment ink composition of the present invention has a solid content of 30 to 70% by weight, preferably 35 to 60% by weight. If the solid content exceeds 70% by weight, it is difficult to adjust the viscosity of the water-based pigment ink composition, and the viscosity of the water-based pigment ink composition may become too high, resulting in a decrease in the amount of ink flow. Conversely, if the solid content is less than 30% by weight, it is necessary to add a large amount of the resin emulsion to the aqueous pigment ink composition, and there is a concern that the viscosity of the aqueous pigment ink composition will be too low. There is a possibility that the adhesiveness of the handwriting by the aqueous pigment ink composition to the surface of the object will not be sufficiently strong.

[Resin particles]
Examples of the resin particles that can be added in the present invention include styrene / acrylic resin particles such as low-paque ultra (hollow white resin particles), and Muticle PP240D (flat white resin particles: solid content: 50%, average particle size: Styrene resin particles such as 0.5 μm). These resin particles are used in order to reduce the solid-state average specific gravity in the ink and improve the concealability. The shape and color of such resin particles are not particularly limited, and may be any shape such as an indefinite shape, a hollow shape, and a flat shape.
The color of the resin particles may be colorless and transparent or white. In addition, resin particles exhibiting other colors may be used, but if white, a handwriting becomes clearer when a material having a high liquid-absorbing property such as cloth exhibits a particularly dark color.

[surface tension]
The surface tension of the aqueous pigment ink composition of the present invention needs to be 35 mN / m or more. If it is less than 35 mN / m, the resin component in the water-based pigment ink composition, and also titanium dioxide pigment and pearl mica and / or mica will permeate in a short time when written on a black cloth. There is concern that it will be difficult to show handwriting on

[viscosity]
The ink composition of the present invention has a viscosity higher than that of a general ink composition and a sufficiently strong thixotropic property at a temperature of 20.0 ± 3.0 ° C.
Specifically, the viscosity is 80 to 450 mPa · s at a shear rate of 1 (1 / s), preferably 85 to 300 mPa · s, and more preferably 90 to 120 mPa · s. By setting it as such a viscosity range, prevention of sedimentation of a pigment and generation | occurrence | production of the hard cake by it can be prevented. Furthermore, if the viscosity is lower than 80 mPa · s at a shear rate of 1 (1 / s), the ink composition will flow too much and penetrate into the material such as cloth, resulting in set-off. become. On the other hand, if the viscosity is higher than 450 mPa · s, the fluidity of the ink composition is lowered, ink may not be supplied from the writing instrument, and writing may be difficult.
In addition, the viscosity is 10 to 30 mPa · s at a shear rate of 1000 (1 / s), preferably 13 to 25 mPa · s, and more preferably 15 to 22 mPa · s. By having the viscosity in such a range, the above properties at a shear rate of 1 (1 / s) can be more satisfactorily exhibited, and the water pigment ink composition can be marked, for example, by such thixotropy. It is stored in the ink storage part of the pen, and when using this marking pen, the shearing force related to the aqueous pigment ink composition of the chip can surely write and supply an appropriate amount of ink from the storage part to the chip. Is possible.

In the ink composition of the present invention, a water-soluble organic solvent can be used in combination with water as a solvent. Examples of such a water-soluble organic solvent include lower alcohols such as ethanol, isopropanol, and butanol; ethylene glycol, propylene Polyhydric alcohols such as glycol and glycerine; Polyalkylene glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether , Ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene group Call monopropyl ether, alkyl ethers of alkylene glycols such as propylene glycol monobutyl ether and the like are used.
Among these, preferable water-soluble organic solvents are ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and glycerin, and more preferably ethylene glycol and propylene glycol.

The water contained in the aqueous pigment ink composition of the present invention can be 30.0 to 50.0% by weight, preferably 35.0 to 45.0% by weight in the ink composition. When the concentration of water in the ink composition exceeds 50.0% by weight, the drying speed of the coating film becomes slow. Conversely, when the concentration of water in the ink composition is less than 30.0% by weight, the cap-off property deteriorates. In addition, the outflow property of the ink also deteriorates.
When the water-based pigment ink composition of the present invention contains a water-soluble organic solvent, the water-soluble organic solvent is contained in the ink composition in an amount of 3.0 to 20.0% by weight, preferably 5.0 to 15.0. It can contain in the range of weight%.
When the concentration of the water-soluble organic solvent exceeds 20.0% by weight in the ink composition, there is a concern that the drying speed of the aqueous ink coating film after writing tends to be slow, and the usability is deteriorated. When the concentration of the solvent is less than 3.0% by weight in the ink composition, the cap-off property tends to deteriorate, and the outflow property of the ink may also deteriorate.

Furthermore, if necessary, thixotropic agents, preservatives, antifungal agents, surfactants, ultraviolet absorbers, infrared absorbers, antioxidants, non-thermochromic pigments, non-thermochromic dyes, fluorescent brighteners Well-known additives such as antifoaming agents and leveling agents can be contained as appropriate. Moreover, an inorganic pigment or an organic pigment can also be contained as a colorant other than white. When it contains such a colorant, it mix | blends so that the content rate in an aqueous pigment ink composition may be 0.01 to 20 weight%, Preferably it is about 0.1 to 15 weight%.
When using thixotropic agents, acrylic emulsions such as ammonium polyacrylate such as MOWIPLAS XW330 (Clariant), primal DR-72, and primal TT-615 (Rohm & Haas) are used as the thixotropic agent. A known thixotropic agent such as can be used. Such a thixotropic agent can be contained in the aqueous pigment ink composition in an amount of 0.1 to 5.0% by weight, preferably 0.1 to 3.0% by weight. When such a thixotropic agent is contained, if its content exceeds 5.0% by weight, there is a concern that the viscosity becomes too high and the ink outflow properties deteriorate, and the content is 0.1% by weight. If it is less than%, the possibility that the viscosity becomes too low increases, and there is a concern that the storage stability deteriorates.

  The water-based pigment ink composition of the present invention is prepared by blending a predetermined amount of these components and mixing and stirring them uniformly with a conventionally known disperser such as a ball mill, homomixer, bead mill, roll mill or the like. be able to. Moreover, when using together an inorganic pigment, the composition which disperse | distributed the pigment may be prepared previously, and this and an emulsion may be mixed by a suitable ratio.

[Use of water-based pigment ink composition and marking pen]
The aqueous pigment ink composition of the present invention is used exclusively for marking pens. Furthermore, it can be used for marking pens for writing on liquid-absorbing surfaces such as cloth and porous bodies. The marking pen at that time may have a known structure, a fiber bundle or plastic as a chip, and a water-based pigment ink composition storage part in the shaft cylinder, and further in the water-based pigment ink composition storage part A spherical object such as stainless steel intended to be stirred by shaking a marking pen or the like can also be stored.
The water-based pigment ink composition container is preferably connected to an ink supply path via a valve body, and is supplied to a pen tip such as a marking pen through the ink supply path.
The chip is formed of a continuous porous member not only when it is formed of fiber bundles but also when it is formed of plastic. In particular, when the chip is composed of fiber bundles, the fiber diameter of the fiber is preferably 10 to 30 denier, and particularly preferably 15 to 25 denier, so that the aqueous pigment ink composition is stabilized at the tip of the chip. To supply.
Since the water-based pigment ink composition of the present invention has specific properties in the diameter and viscosity of pigment particles, a titanium oxide pigment, a pearl mica pigment and / or a mica pigment can be used for a cloth or the like.
The water-based pigment ink composition of the present invention and the cloth using the marking pen are premised on having a dark color such as black, but the color of the water-based pigment ink composition of the present invention is sufficiently improved by writing. As long as it is a visually recognizable color, cloths of other colors may be targeted.

[Method for producing aqueous pigment ink composition]
Two examples of the production method of the aqueous pigment ink composition of the present invention are shown below, but the production method is not limited to these two examples.
(Manufacturing method 1)
A pigment, a dispersion resin and a pigment are mixed and stirred in a pigment dispersion container, and the pigment is pulverized to disperse the pigment until the particle diameter of the pigment reaches the target particle diameter. Alternatively, a colored pigment dispersion is produced.
Next, resin particles, water, ethylene glycol, preservative, acrylic emulsion, and if necessary, a colorant are added and mixed. Next, a thixotropic agent is added and further uniformly mixed to prepare a viscosity in the desired range.
(Manufacturing method 2)
By mixing and stirring a solvent, a dispersion resin, and a titanium dioxide pigment in a pigment dispersion container, the titanium dioxide pigment is pulverized to disperse the pigment until the particle diameter of the titanium dioxide pigment reaches the target particle diameter. To produce a titanium dioxide pigment dispersion.
A pigment, a dispersion resin, and a pearl pigment are mixed and stirred in a separately prepared container for pigment dispersion, and the pearl pigment is pulverized to disperse the pigment until the particle size of the pearl pigment reaches the target particle size. To produce a pearl pigment dispersion.
Next, a white pigment dispersion or a colored pigment dispersion is produced by mixing the produced titanium dioxide pigment and the pearl pigment dispersion so as to obtain a target concentration.
Thereafter, resin particles, water, ethylene glycol, preservative, acrylic emulsion, and if necessary, a colorant are added and mixed. Next, a thixotropic agent is added and further uniformly mixed to prepare a viscosity in the desired range.

[Examples and Comparative Examples]
Manufacture of water-based ink In a pigment dispersion container, a solvent, a dispersion resin, and a pigment are mixed and stirred so that the weight percentage of each component of the water-based ink is as shown in Tables 1 and 3 below. The pigment is dispersed until the particle diameter of the pigment reaches the target particle diameter to produce a white pigment dispersion or a colored pigment dispersion.
Specifically, titanium, pearl mica / mica pigment, or colored pigment is mixed in a dispersion obtained by mixing water, Joncrill J-62 as a dispersion resin, Proxel XL-2, and coatside PH2. This was stirred and then pulverized by a bead mill or the like to prepare a white pigment dispersion or a colored pigment dispersion.
Resin particles, water, ethylene glycol, preservatives are added to the white pigment dispersion or colored pigment dispersion obtained so as to have the blending amounts shown in Tables 1 and 3 so as to have the compositions shown in Tables 2 and 4. Add acrylic emulsion, colorant if necessary, and mix. Next, a thixotropic agent is added and further uniformly mixed to prepare a viscosity in the desired range.
Here, the particle size accumulation of the pearl pigment alone is 10% cumulative, the particle size is 2.0 μm, 50% cumulative, the particle size is 10.0 μm, 90% cumulative, the particle size is 13.0 μm, and the cumulative particle size is 95%. The diameter is 17.0 μm.
Further, the particle size accumulation of only the titanium dioxide pigment is the same as the particle size accumulation of the white pigment dispersion 4.

Preparation of experimental sample The produced water-based pigment ink composition is filled into a polypropylene container in the main body of the pen with a stainless steel stirrer that is covered with a polypropylene cap at both ends of a cylindrical container. A chip formed of a fiber bundle or plastic after being covered with the valve is provided downstream of the valve.

[Measuring method]
Measuring method of viscosity (at shear rate 1 (1 / S), 1000 (1 / S)) Thermo Scientific HAAKE rheometer RS75 was used as a measuring device for viscosity. A coaxial double cylinder DG41 is used as a jig, and the measurement mode is set to CR Flow curve speed range: 0.761-4185 [1 / s] at a temperature of 20.0 ± 1.0 ° C. It was measured.
Surface tension: measured with a surface tension meter, sample temperature is 20.0 ± 3.0 ° C
Sinking (whiteness of the handwriting): Visually confirming the sinking of the writing line written on the black cotton broad ○: The writing line does not sink.・ ・ ・ Concealment but shows concealment weaker than ○ ×: The writing line sinks considerably… No concealment

Washing resistance: Written once on test cloth, allowed to air dry for more than 1 day, and then 5 times with synthetic detergent (trade name attack) and powder soap (Miyoshi soap) for 15 minutes each before and after washing The location was evaluated.
The synthetic detergent was used in an aqueous solution having a concentration of 0.07% by weight, and the soap powder was used in an aqueous solution having a concentration of 0.13% by weight.
○: The writing line does not change before and after washing ×: Almost falls due to washing

Dispersing resin: Jonkrill J-62 (styrene / acrylic acid copolymer, solid content 34% by weight, manufactured by BASF Japan, water 55%)
Acrylic resin emulsion A ... Polysol PSA SE1300N (Showa Denko, nonvolatile content 49%) (Tg is -50 ° C)
Acrylic resin emulsion B ... Boncoat AB886 (DIC, solid content 49-51%) (Tg -38 ° C)
Acrylic resin emulsion C ... Boncoat 3256 (DIC, solid content 45%) (Tg is -10 ° C)
Acrylic resin emulsion D ... Boncoat CF6140 (DIC, solid content 47-49%) (Tg 12 ° C)
Acrylic resin emulsion E ... Primal SF-021 (Rohm & Haas, solid content 45%) (Tg 21 ° C)
Resin ball ... Muticle PP240D
Thixotropic agent A ... MOWIPLUS XW330
Thixotropic agent B ... Primal DR-72
Thixotropic agent C ... Primal TT-606
Titanium oxide: Taipaque CR95 (Ishihara Sangyo)
Pearl pigment ... Iriodin 123
Preservative: Proxel XL-2 (1,2-benzisothiazol-3 (2H) -one) (manufactured by Arch Chemicals Japan)
Antifungal agent: Coat side PH2 (antiseptic antifungal agent, organic iodine compound) (manufactured by Nippon Enviro Chemicals)
Color pigment ...
Red pigment: Shimura Fast Red 4127 (PR267, manufactured by DIC)
Blue pigment: FASTOGEN BLUE TGR (P.B.15: 3, manufactured by DIC)
Green pigment: FASTOGEN GREEN B (PG7, manufactured by DIC)
Orange pigment: First Orange RJW-A (PO16, manufactured by Sanyo Dye)
Purple pigment: FASTOGEN SUPER VIOLET RVS (manufactured by PV23.DIC)

According to the white aqueous pigment ink compositions of Examples 1 to 7 which are examples in accordance with the present invention, the writing line slightly drops before and after washing with soap with soap because of excellent washing resistance, but writing before and after washing with synthetic detergent. There is no change in the line. On the other hand, Comparative Example 1 containing no pearl pigment or mica, and Comparative Examples 2 and 3 using an acrylic emulsion having a Tg exceeding −5 ° C., both depend on either synthetic detergent or soap. It can be seen that even after washing, the handwriting is almost lost and the washing resistance is poor.
The effect relating to the sinking is an effect that varies depending on the degree to which the written line soaks into the black cloth. The water-based pigment ink composition according to Example 4 may have less pearl pigment than the water-based pigment ink compositions of other examples, and the titanium dioxide pigment may sink due to soaking into the black cloth. However, in the other examples, the writing line did not sink and the hiding property was sufficient. On the other hand, in Comparative Example 1 containing no pearl pigment or mica, and in Comparative Example 3 where the Tg of the resin emulsion resin was as high as 21 ° C., the water-based ink submerged. According to Comparative Example 2 in which the glass transition temperature (Tg) in the present invention is not as high as that of Comparative Example 3, no sinking of the handwriting is observed.
Examples of Examples 8 to 10, which are examples according to the present invention, are aqueous pigment ink compositions in which the aqueous pigment ink composition is not white but is colored in other colors. These examples are also examples. 1 to 7 shows the same properties as the aqueous pigment ink composition, and since the aqueous pigment ink composition of Comparative Example 4 uses the white pigment dispersion 4 used in Comparative Example 1, it contains a pearl pigment or a mica pigment. Not. Therefore, it turns out that the property similar to the water-based pigment ink composition of the comparative example 1 is shown.

Claims (5)

Contains titanium dioxide pigment and pearl mica pigment and / or mica pigment in a weight ratio of titanium dioxide pigment: pearl mica pigment and / or mica pigment in a range of 9: 1 to 7: 3 , and glass transition Contains a resin emulsion having a temperature (Tg) of −5 ° C. or less, a surface tension of 35 mN / m or more, a viscosity at a shear rate of 1 (1 / s) of 80 to 450 mPa · s, and a shear rate of 1000 (1 / s ) Is a water-based pigment ink composition having a viscosity of 10 to 30 mPa · s. The aqueous pigment ink composition according to claim 1 , wherein the resin emulsion having a glass transition temperature (Tg) of -5 ° C or lower is an acrylic resin emulsion. A marking pen formed by storing the water-based pigment ink composition according to claim 1 or 2 in an ink storage unit. The marking pen according to claim 3 , wherein the yarn diameter of the fibers constituting the tip is 10 to 30 denier. The marking pen according to claim 3 or 4 , wherein the marking pen is for writing on the liquid-absorbing surface .