JP2020070346A - Oily ink composition for writing instruments, and writing instrument including the same - Google Patents

Abstract

To provide an oily ink composition for writing instruments that is excellent in re-dispersibility and color development of handwriting.SOLUTION: An oily ink composition for writing instruments contains YInMn blue pigment particles, a dispersant, and an organic solvent.SELECTED DRAWING: None

Description

  The present invention relates to an oil-based ink composition for writing instruments. More specifically, the present invention relates to an oil-based ink composition for writing instruments, which is excellent in storage stability of ink and color development of handwriting. The present invention also relates to a writing instrument using the composition.

  Conventionally, an oil-based ink composition for a writing instrument using a pigment such as titanium oxide has been known in order to obtain a handwriting having a hiding property. Furthermore, it has become known that a pastel or chromatic handwriting can be obtained while hiding the base by using a complementary color pigment in combination with such a highly hiding ink composition. Is being actively studied.

However, when a pigment having a large specific gravity such as titanium oxide is used, if the pigment settles into a so-called hard cake with the passage of time, redispersion may be difficult. Therefore, attempts have been made to modify various materials used in the composition and prevent sedimentation of the pigment. However, with the techniques reported hitherto, although it is possible to slow down the sedimentation rate, it is unavoidable that a hard cake will be formed over a long period of time, and in reality the measures have not led to sufficient results. Is.
Furthermore, measures such as increasing the ink viscosity and expressing the structural viscosity by using so-called gelling agents and thickeners are also under study. However, when the ink composition having these countermeasures is used for a writing instrument using a pen tip such as a fiber bundle or a porous body, the ink discharge amount may be reduced.
As described above, with respect to storage stability over time of an ink composition containing a pigment having a large specific gravity, there is room for improvement in the conventional techniques, and further improvement methods have been studied (for example, Patent Document 1).

  Patent Document 1 describes an ink for a writing instrument that uses titanium oxide having a negative zeta potential, a hydrocarbon solvent, and a resin soluble in the hydrocarbon solvent. This ink has improved redispersibility.

  As described above, the conventional technique has succeeded in improving redispersibility to some extent. However, when the ink is subjected to external pressure such as vibration when it is carried, the pigment particles having a large specific gravity such as titanium oxide are in close contact with each other, and the closest packing is easy, which makes it easier to make a hard cake. Therefore, there is room for improving the storage stability of the ink.

  Also, when writing on paper with a low-viscosity oil-based ink that uses titanium oxide, the specific gravity of titanium oxide causes the titanium oxide to enter between the fibers of the paper during the process of the ink penetrating between the fibers of the paper. As a result, there is also a problem that it is difficult to obtain good handwriting color development.

The above problems are also common to pigment particles having a large specific gravity other than titanium oxide.
"YInMn blue (Inmin blue)", which is a blue pigment composed of a composite oxide of yttrium, indium and manganese, was newly discovered in 2009 for the first time in about 200 years. However, since the specific gravity thereof is 5.9, which is even larger than the specific gravity of titanium oxide of about 4.0 (for example, Non-Patent Document 1), when the blue pigment is used in the oil-based ink composition for a writing instrument, There was concern about the storage stability of such ink and the color development of handwriting.

JP 2012-131927 A

    Shepherd Color Japan Inc., “New color <Blue 10G513> has been launched”, [online], [Search on September 3, 2018], Internet <URL: http://home.n00.itscom.net/din/ _userdata / Blue_10G513% 20_2017.pdf>

  INDUSTRIAL APPLICABILITY According to the present invention, various components such as pigments can easily be redispersed without forming a hard cake by sedimentation under the influence of external pressure such as vibration with respect to ink over time. It is an object of the present invention to provide an oil-based ink composition for a writing instrument, which is excellent in color development of handwriting.

The present invention is
"1. An oil-based ink composition for a writing instrument, comprising pigment particles, a dispersant, and an organic solvent, wherein the pigment particles are YInMn blue pigment particles.
2. 2. The oil-based ink composition for a writing instrument as described in 1 above, wherein the dispersant is a wetting dispersant having an acid value and / or an amine value.
3. The acid dispersant having an acid value and / or an amine value has an acid value of 10 mgKOH / g to 140 mgKOH / g and an amine value of 10 mgKOH / g to 140 mgKOH / g. The oil-based ink composition for a writing instrument as described in 1.
4. Any one of the above items 1 to 3, wherein the content of the wetting dispersant in the oil-based ink composition is 0.1% by mass to 20.0% by mass based on the total mass of the oily ink composition. An oil-based ink composition for a writing instrument according to the item.
5. The oil-based ink composition for a writing instrument according to any one of items 1 to 4, wherein the organic solvent is an alcohol-based organic solvent and / or a glycol ether-based organic solvent.
6. A writing instrument containing the composition according to any one of items 1 to 5. It is.

  According to the present invention, it is possible to provide an oil-based ink composition for a writing instrument which is excellent in redispersibility and color development of handwriting while maintaining the writing ability equal to or higher than that of a conventional writing instrument.

  Hereinafter, embodiments of the present invention will be described in detail. In the present specification, “parts”, “%”, “ratio”, etc. indicating the composition are based on mass unless otherwise specified, and the content refers to the composition based on the mass of the oil-based ink composition. It is the mass% of the component.

  The oil-based ink composition for a writing instrument according to the present invention (hereinafter, sometimes referred to as “oil-based ink composition” or “composition”) contains YInMn blue pigment particles, a dispersant, and an organic solvent. It consists of Hereinafter, each component constituting the oil-based ink composition according to the present invention will be described.

<Pigment particles>
The pigment particles used in the present invention are generally called “YInMn blue (inmin blue)”, which is a blue pigment composed of a composite oxide of yttrium, indium, and manganese, and has a chemical formula of Y (In, Mn) O ₃ . And is produced by inserting Mn into the trigonal bipyramidal atomic site of the crystal structure of YInO ₃ .

  The average particle size of the YInMn blue pigment particles is preferably 0.01 μm to 30 μm, more preferably 0.05 μm to 20 μm, and further preferably 0.1 μm to 10 μm. When the average particle size of the YInMn blue pigment particles is within the above numerical range, even if the pigment particles settle in the oil-based ink composition, the redispersibility thereof can be sufficiently maintained, and the color development of handwriting is also improved. Excel. Further, when an oil-based ink composition containing YInMn blue pigment particles having an average particle diameter within the above numerical range is used for a writing instrument such as a marking pen, the ink ejection property can be improved. The average particle diameter of the YInMn blue pigment particles is measured by using a standard sample or another measurement method using a laser diffraction particle size distribution analyzer (trade name "Microtrac HRA9320-X100", manufactured by Nikkiso Co., Ltd.). It can be measured by the particle diameter (D50) at a volume cumulative 50% of the particle size distribution measured by a laser diffraction method based on the numerical value calibrated by the method. In the present specification, the “average particle diameter” of YInMn blue pigment particles refers to the average particle diameter on a volume basis, unless otherwise specified. Since the YInMn blue pigment particles have the above-mentioned effects in the dispersed state in the oil-based ink composition, it is preferable to obtain the dispersed particle diameter.

  The content of YInMn blue pigment particles in the oil-based ink composition is preferably 1% by mass to 40% by mass, and more preferably 2% by mass to 30% by mass, based on the total mass of the oil-based ink composition. It is more preferably 3% by mass to 25% by mass. When the content of the pigment particles is within the above numerical range, it is possible to prevent deterioration of ink dischargeability and to provide an oil-based ink composition having excellent color development of handwriting.

<Dispersant>
The oil-based ink composition according to the present invention comprises a dispersant. Here, the dispersant has an interaction site for the YInMn blue pigment particles and an interaction site for the organic solvent, and has a function of stabilizing the dispersion of the YInMn blue pigment particles in the organic solvent. Generally, they are classified into resin type dispersants (for example, polymer dispersants), surfactants (for example, low molecular dispersants), and dye derivatives. As the dispersant (that is, the resin-type dispersant, the surfactant and / or the pigment derivative), a dispersant that is normally used can be used. These dispersants may be used alone or as a mixture of two or more.

  Examples of the resin-type dispersant include polycarboxylic acid esters such as polyurethane and polyacrylate, unsaturated polyamides, polycarboxylic acids, polycarboxylic acid amine salts, polycarboxylic acid ammonium salts, polycarboxylic acid alkylamine salts, and polysiloxanes. A long-chain polyaminoamide phosphate, a hydroxyl group-containing polycarboxylic acid ester, an amide formed by the reaction of poly (lower alkyleneimine) with a polyester having a free carboxyl group, or a salt thereof, (meth) acrylic acid-styrene copolymer Polymer, (meth) acrylic acid- (meth) acrylic acid ester copolymer, styrene-maleic acid copolymer, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl ether, ketone resin, hydroxyethyl cellulose and derivatives thereof, Styrene - such as amine oligomer synthetic resin or a polyester such as acrylic acid copolymer can be exemplified.

As such a dispersant, a resin-type dispersant is preferable in view of its excellent redispersibility and color development of handwriting, and a wet dispersant is particularly preferably used in consideration thereof. Here, the wetting dispersant is adsorbed on the surfaces of the YInMn blue pigment particles, and the wetting dispersants are hydrogen-bonded to each other, so that the particles are separated from each other and the distance between the YInMn blue pigment particles is kept at a certain value or more. It is possible to form such a loose and bulky network and prevent the YInMn blue pigment particles from directly aggregating with each other, and a wet dispersion effect can be obtained. As a result, agglomeration of YInMn blue pigment particles having a very large specific gravity is suppressed by the wetting dispersant, and even if an agglomerate is formed, an agglomerate having a relatively low-density network is formed. Therefore, the oil-based ink composition according to the present invention is hardly separated by standing and hard caked, and can be easily redispersed even when sedimentation occurs.
Further, since the YInMn blue pigment particles and the wetting dispersant form a network, the ink penetrates between the fibers of the paper when writing on the paper surface with the writing instrument using the oil-based ink composition of the present invention. In the process, the YInMn blue pigment particles are prevented from entering between the fibers of the paper, and the YInMn blue pigment particles are floated on the paper, whereby it is possible to obtain a vivid coloring property.
Further, a writing instrument using the oil-based ink composition according to the present invention is a process in which the ink penetrates between fibers of the paper even when writing is performed not only on a light-colored paper such as white but also on a dark-colored paper such as black. In the above, by suppressing the YInMn blue pigment particles from entering between the fibers of the paper and allowing the YInMn blue pigment particles to float on the paper, it is possible to obtain a vivid coloring property. In the present specification, “dark color such as black” means a lightness of 3.0 or less / saturation of 1.0 or less if it is black, and a hue of 10 GY to 5 BG if it is a so-called blackboard green. / Lightness 2.5 to 4.0 / Saturation 1.0 to 4.0, and other colors such as blue means lightness 4.0 or less / saturation 4.0 or less.

As such a wetting dispersant, a wetting dispersant having an acid value and / or an amine value is more preferably used in consideration of excellent redispersibility and color development of handwriting.
Regarding the wetting dispersant having an acid value and / or an amine value, the acid value of the wetting dispersant is preferably 10 mgKOH / g to 140 mgKOH / g, more preferably 30 mgKOH / g to 140 mgKOH / g, Further, it is more preferably 30 mgKOH / g to 100 mgKOH / g. This is because by setting the acid value of the wetting and dispersing agent within the above numerical range, a stable network is formed, so that stable redispersibility can be easily obtained and vivid color development is easily obtained. Further, it is easy to further improve the fixing property of the oil-based ink composition on the writing material.
The amine value of the wetting and dispersing agent is preferably 10 mgKOH / g to 140 mgKOH / g, more preferably 30 mgKOH / g to 140 mgKOH / g, and further preferably 30 mgKOH / g to 100 mgKOH / g. This is because by setting the amine value of the wetting and dispersing agent within the above numerical range, a stable network is formed, so that stable redispersibility can be easily obtained and vivid color development is easily obtained. Further, it is easy to further improve the fixing property of the oil-based ink composition on the writing material.
Furthermore, the wetting and dispersing agent having both an acid value and an amine value has an acid value and an amine value, so that the balance in the ink is maintained, a stable network is easily formed, and redispersibility and handwriting are improved. It is more preferable because the coloring property of is easily excellent.
The acid value is represented by the number of mg of KOH of potassium hydroxide required to neutralize 1 g of the sample, and the amine value is the equivalent of KOH of hydrochloric acid required to neutralize 1 g of the sample. It shall be expressed in mg.

As the wetting dispersant having an acid value and / or an amine value, an alkylol ammonium salt of a basic acid, a salt of a polyaminoamide and an organic acid, or an organic acid and an alkyl ammonium salt are preferably used.
Regarding the alkylol ammonium salt of a basic acid, the basic acid preferably has a plurality of acid groups, specifically, an acidic polymer having a plurality of acid groups, such as polyacrylic acid or polymethacrylic acid. , Polyvinyl sulfonic acid, polyphosphoric acid, etc. are preferably used. Other than this, a polymer obtained by polymerizing an unsaturated fatty acid such as crotonic acid is also an example of the basic acid. The alkylol ammonium salt of basic acid can be obtained by reacting these basic acids with alkylol ammonium. The salt obtained by such a reaction contains the following partial structure.
^{-C (= O) -N (-R} 1) (- R 2 -OH)
Here, R ¹ is an alkyl group and R ² is an alkylene group. The alkylol ammonium salt of a basic acid used in the present invention is preferably a polymer having such a partial structure.
Regarding the salt of polyaminoamide and organic acid, or the organic acid and alkylammonium salt, the organic acid is a low molecular weight polyester acid or an organic acid having one or more carboxy groups, sulfonic acid groups, phosphoric acid groups, or phosphonic acid groups. Specifically, specifically, alkylcarboxylic acid, aromatic carboxylic acid, polycarboxylic acid, alkylsulfonic acid, aromatic sulfonic acid, polysulfonic acid, alkylphosphoric acid, aromatic phosphoric acid, polyphosphoric acid, alkylphosphonic acid, aromatic Group phosphonic acids, polyphosphonic acids, and the like are mentioned, and are preferably used.

Further, for the wetting dispersant having an acid value and / or an amine value, polymers containing an acidic group can also be used.
Regarding polymers containing an acidic group, having the acidic group such as a carboxy group, the above-mentioned functions are exhibited. That is, in consideration of excellent redispersibility and color development of handwriting, it is preferable to use polymers containing an acidic group, preferably copolymers containing an acidic group, as the wetting and dispersing agent. Are preferably polymers containing a carboxy group, a sulfonic acid group, a phosphonic acid group, a phenolic hydroxyl group, a carboxylic acid anhydride group and the like.

The weight average molecular weight of the wetting dispersant having an acid value and / or an amine value is not particularly limited, but the weight average molecular weight is preferably 1,000 to 100,000, and 5,000 to 20,000. Is more preferable.
In the present invention, the mass average molecular weight means a value measured by gel permeation chromatography using polystyrene as a standard substance, and can be measured by a method according to JIS-K-7252-1 (issued in 2008).

  In the present invention, the wetting dispersant is bonded to the surface of the YInMn blue pigment particles by the groups as described above, and is hydrogen-bonded to another wetting dispersant, so that the main chain structure of the polymer is between the YInMn blue pigment particles. It is believed that they enter and separate the YInMn blue pigment particles from each other.

  Such a wetting and dispersing agent is generally commercially available, for example, ANTI-TERRA U100 (acid value: 50 mgKOH / g, amine value: 35 mgKOH / g), ANTI-TERRA 203 (acid value: 51 mgKOH / g, amine value: 51 mgKOH / g), ANTI-TERRA 204 (acid value: 41 mgKOH / g, amine value: 37 mgKOH / g), DISPERBYK-106 (acid value: 132 mgKOH / g, amine value: 74 mgKOH / g), DISPERBYK-111 (acid value). 129 mgKOH / g), DISPERBYK-118 (acid value: 36 mgKOH / g), DISPERBYK-180 (acid value: 94 mgKOH / g, amine value: 94 mgKOH / g) (both trade names, manufactured by BYK Chemie Co., Ltd.), TEGO Dispe. s630 (acid value: 50mgKOH / g), TEGO Dispers700 (acid value: 27mgKOH / g, amine value: 22mgKOH / g) (all trade names, manufactured by Evonik Degussa Japan Co., Ltd.), and the like. These wetting and dispersing agents may be used alone or as a mixture of two or more.

  The content of the wetting dispersant in the oil-based ink composition is preferably 0.1% by mass to 20% by mass, and is 0.1% by mass to 10% by mass, based on the total mass of the oil-based ink composition. Is more preferable, and the most preferable range is 0.1% by mass to 3.0% by mass. This is because by setting the content of the wetting and dispersing agent within the above numerical range, a stable network can be formed, so that stable redispersibility can be easily obtained and vivid color development can be easily obtained. Further, it is easy to further improve the fixing property of the oil-based ink composition on the writing material.

  Regarding the compounding ratio of the wetting dispersant (wetting dispersant / YInMn blue pigment particles) to the YInMn blue pigment particles, considering that the redispersibility, the color development of the handwriting, and the writability are excellent in a well-balanced manner, It is preferably 0.1% to 20% on the basis, and in consideration of redispersibility and color development of handwriting, the compounding ratio is preferably 0.1% to 15% on a mass basis, Furthermore, it is preferable that the compounding ratio is 0.5% to 15% on a mass basis.

<Organic solvent>
The oil-based ink composition according to the present invention comprises an organic solvent.
Conventional organic solvents can be used as the organic solvent. Moreover, the oil-based ink composition may contain two or more kinds of organic solvents.
Specifically, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol, t-butyl alcohol, pentyl alcohol, benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol. , Benzyl glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol diethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono Phenyl ether, Pyrene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monophenyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monophenyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monophenyl ether , Methyl lactate, ethyl lactate and γ-butyrolactone.

  Among the above-mentioned organic solvents, alcohol-based organic solvents and / or glycol ether-based organic solvents are more preferable, ethyl alcohol and n-propyl alcohol, from the viewpoints of quick-drying handwriting and solubility of usable resins and additives. , Isopropyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monophenyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and the like.

  The content of the organic solvent in the oil-based ink composition is preferably 40 to 80 mass% based on the total mass of the oil-based ink composition.

Depending on the embodiment, the oil-based ink composition according to the present invention preferably uses an organic solvent having a vapor pressure of 5.0 to 50 mmHg, more preferably 10 to 50 mmHg at 20 ° C. where the organic solvent is likely to volatilize. Such an organic solvent is preferable when the writing instrument containing the oil-based ink composition is a marking pen.
By using such an organic solvent, it is possible to improve the dryness of the handwriting, so that when the handwriting is touched, undried ink may adhere to the hand or form handwriting on the writing surface. Good handwriting can be formed without causing a problem such as contaminating an empty space.

As the organic solvent having a vapor pressure of 5.0 to 50 mmHg at 20 ° C., ethyl alcohol (45), n-propyl alcohol (14.5), isopropyl alcohol (32.4), n-butyl alcohol (5.5). , Alcohol solvents such as isobutyl alcohol (8.9), s-butyl alcohol (12.7), t-butyl alcohol (30.6) and t-amyl alcohol (13.0), ethylene glycol monomethyl ether ( 8.5), glycol ethers such as ethylene glycol monoisopropyl ether (6.0), ethylene glycol diethyl ether (9.7), propylene glycol monomethyl ether (7.6), propylene glycol monoethyl ether (10.6) Organic solvent, n-heptane (35.0), n- Kutane (11.0), isooctane (41.0), methylcyclohexane (37.0), ethylcyclohexane (10.0), toluene (24.0), xylene (5.0 to 6.0), ethylbenzene ( 7.1) and other hydrocarbon-based organic solvents, methyl isobutyl ketone (16.0), methyl n-propyl ketone (12.0), methyl n-butyl ketone (12.0), di-n-propyl ketone (5 .2) and other ketone organic solvents, n-butyl formate (22.0), isobutyl formate (33.0), n-propyl acetate (25.0), isopropyl acetate (48.0), n-butyl acetate. (8.4), isobutyl acetate (13.0), ethyl propionate (28.0), n-butyl propionate (45.0), methyl butyrate (25.0), ethyl butyrate (11.0) How such ester organic solvents.
The numbers in parentheses indicate the vapor pressure (mmHg) of each organic solvent at 20 ° C. These organic solvents may be used alone or as a mixture of two or more.

The oil-based ink composition according to the present invention preferably contains a high-boiling point organic solvent having a boiling point of 160 ° C to 250 ° C, depending on the embodiment. Such a high boiling point organic solvent is preferable when the writing instrument containing the oil-based ink composition is a ballpoint pen.
Further, such a high-boiling point organic solvent may be contained in an oil-based ink composition which is used by being housed in a marking pen or the like. This makes it possible to adjust the drying speed of the handwriting and suppress whitening of the handwriting which is likely to occur in a humid environment. In particular, when an organic solvent having a vapor pressure of 5.0 to 50 mmHg at 20 ° C., such as an alcohol solvent having 4 or less carbon atoms and / or a glycol ether solvent having 4 or less carbon atoms, is used together with a high boiling point organic solvent. Therefore, it is preferable to adjust the drying rate.

Examples of the high boiling point organic solvent include benzyl alcohol (205), ethylene glycol monophenyl ether (245), propylene glycol-n-butyl ether (170), dipropylene glycol methyl ether (190), propylene glycol diacetate (190), Propylene glycol dimethyl ether (175), dipropylene glycol-n-propyl ether (212), dipropylene glycol methyl ether acetate (209), propylene glycol phenyl ether (243), tripropylene glycol methyl ether (242), dipropylene glycol- n-butyl ether (229), tripropylene glycol-n-butyl ether (274), p-xylene glycol dimethyl ether (235 Benzyl formic acid (201), benzyl acetate (212), benzyl propionate (222), butyric acid benzyl (240) and isobutyric acid benzyl (230), and the like.
The numbers in parentheses indicate the boiling points (Celsius) of each organic solvent. These high boiling point organic solvents may be used alone or as a mixture of two or more.
The content of the above high boiling point organic solvent is preferably 1 to 10% by mass, and more preferably 2 to 8% by mass, based on the total mass of the organic solvent.

<Resin>
The oil-based ink composition according to the present invention may contain a resin, if necessary, for the purpose of improving fixability of handwriting and suppression of ink leakage.
Examples of the resin include a fixability improver and an ink leakage inhibitor, such as polyvinyl butyral resin, ketone resin, polyacetal resin, polyvinyl alcohol resin, cellulose resin, terpene resin, alkyd resin, phenoxy resin, and polyvinyl acetate resin. However, among them, it is preferable to contain a polyvinyl butyral resin or a ketone resin in consideration of the ease of obtaining the effect as the fixability improver and the ink leakage suppressor. These resins may be used alone or as a mixture of two or more.

<Resin-forming resin>
The oil-based ink composition according to the present invention may optionally contain a spinnability imparting resin. When the writing instrument containing the oil-based ink composition is a ball-point pen, the oil-based ink composition can improve the binding property of the oil-based ink composition by containing the spinnability imparting resin, and the surplus at the tip of the tip Ink generation can be suppressed.
Examples of the spinnability imparting resin include polyvinylpyrrolidone resin. In this case, the content of the spinnability imparting resin in the oil-based ink composition is preferably 0.01 to 3.0 mass% based on the total mass of the oil-based ink composition, and 0.1 to 2.0. More preferably, it is mass%. By setting the content of the spinnability imparting resin within the above numerical range, it is possible to more effectively suppress the generation of excess ink while maintaining the solubility in the oil-based ink composition.

<Lubricant>
The oil-based ink composition according to the present invention may contain a lubricant, if necessary. When the writing instrument that contains the oil-based ink composition is a ball-point pen, the oil-based ink composition contains a lubricant to improve writing performance and prevent wear at the contact portion between the ball receiving seat and the ball, thus improving the durability of the ball-point pen. Can be improved.
As the lubricant, higher fatty acids such as oleic acid, nonionic surfactants having a long-chain alkyl group, polyether modified silicone oil, phosphate ester-based surfactants, fluorine-based surfactants, silicone-based surfactants, Examples thereof include fatty acid alkanolamides, anionic surfactants, cationic surfactants, amphoteric surfactants, and their metal salts, ammonium salts, amine salts, alkanolamine salts and the like. These lubricants may be used alone or as a mixture of two or more.
Among the above-mentioned lubricants, the phosphoric acid ester-based surfactant improves the writing taste, further prevents the abrasion of the ball seat and the ball, and improves the writing performance to secure the ink discharge amount, It is particularly preferable because it is easy to improve the color developability.

Examples of phosphoric acid ester-based surfactants include thiophosphorous acid triesters such as thiophosphorous acid tri (alkoxycarbonylmethyl ester) and thiophosphorous acid tri (alkoxycarbonylethyl ester), polyoxyethylene alkyl ether or polyoxyethylene Phosphoric acid monoesters such as ethylene alkyl aryl ethers, phosphoric acid diesters such as polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers, phosphoric acid triesters such as polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers Alkyl phosphoric acid Examples thereof include esters, alkyl ether phosphates, and their derivatives.
The alkyl group of the above-mentioned phosphate ester-based surfactant has preferably 5 to 18 carbon atoms, and more preferably 10 to 18 carbon atoms. Further, in consideration of the stability over time of the oil-based ink composition, the carbon number of the alkyl group is preferably 12-18.
Moreover, you may use a commercially available phosphoric acid ester type surfactant, for example, Daiichi Kogyo Seiyaku Co., Ltd. plysurf A217E (carbon number of an alkyl group: 14, acid value: 45-58), ply. Surf A219B (carbon number of alkyl group: 12, acid value: 44 to 58), Plysurf A215C (carbon number of alkyl group: 12, acid value: 135 to 155), Plysurf A208N (carbon number of alkyl group: 12) And 13 mixture, acid value: 15 to 58), Toho Chemical Industry Co., Ltd. phosphanol RB-410 (carbon number of alkyl group: 18, acid value: 80 to 90), phosphanol RS-610 ( Examples thereof include carbon number of alkyl group: 13, acid value: 75 to 90, and phosphanol RS-710 (carbon number of alkyl group: 13, acid value: 55 to 75).
The acid value is the number of mg of potassium hydroxide required to neutralize the acidic components contained in 1 g of the sample, and can be measured according to JIS-K-0070.

  The content of the lubricant in the oil-based ink composition is preferably 0.1 to 5.0% by mass, and preferably 0.3 to 3.0% by mass, based on the total mass of the oil-based ink composition. More preferable. By setting the content of the lubricant within the above numerical range, it is possible to further prevent abrasion of the ball seat and the ball while maintaining the stability over time of the oil-based ink composition.

<Organic amine>
When the oil-based ink composition according to the present invention contains a lubricant such as a phosphate ester surfactant, the oil-based ink composition preferably contains an organic amine. When the oil-based ink composition contains an organic amine, the phosphate ester-based surfactant can be neutralized, and the temporal stability of the oil-based ink composition can be further improved.
As the organic amine, any of a primary amine, a secondary amine and a tertiary amine can be used. In consideration of the reactivity with the constituent components of the oil-based ink composition, the secondary amine or the tertiary amine is selected. Preference is given to using.
More specifically, amines having ethylene oxide such as oxyethylene alkylamine and polyoxyethylene alkylamine, alkylamines such as laurylamine and stearylamine, distearylamine, dimethyllaurylamine, dimethylstearylamine and dimethyloctylamine. Aliphatic amines such as dimethylalkylamine are listed.Among them, considering stability in ink and prevention of wear of ball seat and ball when used in combination with a lubricant, amine having ethylene oxide, Dimethylalkylamine is preferred.

The total amine value of the organic amine is preferably in the range of 100 mgKOH / g to 300 mgKOH / g, considering the stability with the phosphoric acid ester and other components. If the amount exceeds 300 mgKOH / g, the reactivity is strong, and thus it easily reacts with the above components, so that the stability with time of the ink tends to be poor. Further, if the total amine value is less than 100 mgKOH / g, the stability of the phosphoric acid ester in the ink tends to be affected, and in the case of an oil-based ballpoint pen, the adsorptivity of metals such as the ball and chip body is poor. Easy to obtain and difficult to obtain lubrication performance. If stability and lubricity with a phosphoric acid ester are further considered, the range of 150 mgKOH / g to 300 mgKOH / g is preferable, if stability is further considered, 200 to 300 mgKOH / g is preferable, and if the most consideration is given, 230 mgKOH / G to 270 mgKOH / g is preferable.
The total amine value indicates the total amount of primary, secondary, and tertiary amines, and is expressed in mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize 1 g of the sample.

  Specific examples of the organic amines include oxyethylene alkylamines and polyoxyethylene alkylamines such as Nymeen L-201 (total amine value: 232 to 246, secondary amine) and L-202 (total amine value: 192-212, tertiary amine), L-207 (total amine value: 107-119, tertiary amine), S-202 (total amine value: 152-166, tertiary amine), S-204 (the same). Total amine value: 120-134, tertiary amine), S-210 (total amine value: 75-85, tertiary amine), DT-203 (total amine value: 227-247, tertiary amine), the same Examples include DT-208 (total amine value: 146 to 180, tertiary amine) (manufactured by NOF CORPORATION). Specific examples of the alkylamine include Farmin 80 (total amine value: 204 to 210, primary amine), Farmin D86 (total amine value: 110 to 119, secondary amine), Farmin DM2098 (total amine value: 254). ~ 265, tertiary amine), Pharmin DM8680 (total amine value: 186-197, tertiary amine) (manufactured by Kao Corporation), Nissan tertiary amine BB (total amine value: 243-263, tertiary amine), the same. FB (total amine value: 230 to 250, tertiary amine) (manufactured by NOF CORPORATION) and the like. These organic amines may be used alone or as a mixture of two or more.

  The content of the organic amine is preferably 0.1 to 10.0 mass% with respect to the total amount of the oil-based ink composition, in consideration of the stability with phosphoric acid ester and other components.

<Shear thinning agent>
The oil-based ink composition of the present invention may contain a shear thinning agent, if necessary. As a result, it is possible to further suppress the occurrence of bleeding in the handwriting. Therefore, even if the material of the writing surface is paper or a fiber material such as cloth having high permeability, the occurrence of bleeding in the handwriting is suppressed. You can
When the writing instrument containing the oil-based ink composition is a ballpoint pen, it is particularly preferable to use a shear thinning agent. As a result, it is possible to prevent ink from leaking from the gap between the ball and the tip when not in use, and to prevent the ink from flowing back when the writing tip is left upright (upright).

  As the shear thinning agent, a non-crosslinked acrylic resin, a crosslinked N-vinylcarboxylic acid amide polymer or copolymer, a noncrosslinked N-vinylcarboxylic acid amide polymer or copolymer, hydrogenated castor oil, Waxes such as fatty acid amide wax and oxidized polyethylene wax, fatty acid metal salts such as stearic acid, palmitic acid, aluminum salts of octylic acid and lauric acid, dibenzylidene sorbitol, N-acyl amino acid compounds, smectite inorganic compounds, montmorillonite compounds Examples thereof include inorganic compounds, bentonite-based inorganic compounds, and hectorite-based inorganic compounds. These shear thinning agents may be used alone or as a mixture of two or more kinds.

<Sucrose fatty acid ester>
The oil-based ink composition according to the present invention may contain sucrose fatty acid ester, if necessary. Thereby, it is possible to suppress the evaporation of the solvent from the pen tip of the writing instrument containing the oil-based ink composition of the present invention, even after exposing the pen tip to the outside air for a long time, without causing blurring etc. Good handwriting can be formed.

The sucrose fatty acid ester is composed of at least one selected from sucrose fatty acid monoester, sucrose fatty acid diester, sucrose fatty acid triester, and sucrose fatty acid polyester.
The fatty acid component of the sucrose fatty acid ester is not particularly limited, and specific examples thereof include lauric acid, myristic acid, palmitic acid, stearic acid, eicosanoic acid, oleic acid and the like.
The HLB value of the sucrose fatty acid ester is preferably 8 to 18, and more preferably 9 to 15. By setting the HLB value of the sucrose fatty acid ester within the above numerical range, it is possible to further suppress the evaporation of the solvent from the pen tip.

  The content of sucrose fatty acid ester in the oil-based ink composition is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass, based on the total mass of the oil-based ink composition. preferable. If the amount is less than 0.1% by mass, it is difficult to obtain the desired effect, and it is possible to add a large amount. However, if the amount is 10% by mass or less, the desired effect is sufficiently obtained.

<Sorbitan fatty acid ester / polyglycerin fatty acid ester>
The oil-based ink composition according to the present invention may contain a sorbitan fatty acid ester and / or a polyglycerin fatty acid ester, if necessary. Thereby, it is possible to suppress the evaporation of the solvent from the pen tip of the writing instrument containing the oil-based ink composition of the present invention, even after exposing the pen tip to the outside air for a long time, without causing blurring etc. Good handwriting can be formed.

The sorbitan fatty acid ester is an ester of sorbitan, which is a reduced product of sorbitol, and a fatty acid, and specific examples of the fatty acid include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, eicosanoic acid, and oleic acid. Etc. Suitable compounds include sorbitan trioleate, sorbitan tristearate, sorbitan tripalmitate and the like.
The polyglycerin fatty acid ester is an ester of polyglycerin and a fatty acid, and specific examples of the fatty acid include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, eicosanoic acid, and oleic acid. .. Suitable compounds include polyglycerin stearic acid ester and polyglycerin behenic acid ester.
The HLB value of the sorbitan fatty acid ester is preferably 2 to 7, and the HLB value of the polyglycerin fatty acid ester is preferably 2 to 9. By setting the HLB value of the sorbitan fatty acid ester and / or the polyglycerin fatty acid ester within the above numerical range, it is possible to further suppress the evaporation of the solvent from the pen tip.

  The sorbitan fatty acid ester and / or polyglycerin fatty acid ester may be added in an amount of 0.1 to 5% by mass, preferably 0.1 to 3% by mass, based on the total amount of the oil-based ink composition. If it is less than 0.1% by mass, it is difficult to impart sufficient dry-up resistance, and it is possible to add a large amount. However, if it is 5% by mass or less, the desired effect is sufficiently obtained. I don't need it.

<Other>
The oil-based ink composition according to the present invention contains an antioxidant, an ultraviolet absorber, an anticorrosive agent, a release agent, a defoaming agent, a solubilizer, a viscosity modifier, a coloring stabilizer, a plasticizer, a chelating agent, if necessary. , A cosolvent such as water may be included.

<Oil-based ink composition for writing instruments>
The viscosity of the oil-based ink composition according to the present invention can be measured using an E-type rotational viscometer (DV-II + Pro, cone-type rotor CPE-42, manufactured by Brookfield) when used in a marking pen. Specifically, the viscosity of the oil-based ink composition at 20 ° C. is preferably 1 mPa · s to 40 mPa · s when measured at a rotation speed of 100 rpm (shear rate 380 sec ⁻¹ ), and preferably 1 mPa · s. More preferably, it is about 20 mPa · s. Further, when measured under the condition that the rotation speed is 20 rpm (shear rate 76 sec ⁻¹ ), it is preferably 1 mPa · s to 60 mPa · s, and more preferably 1 mPa · s to 40 mPa · s. If the viscosity of the oil-based ink composition is within the above numerical range, it is possible to improve the ink dischargeability when used in a marking pen, the color development of the handwriting, the writing properties are excellent, and the non-penetrability of the film etc. Writability on a recording medium is improved.
When used for a ballpoint pen, a viscometer viscometer (RVDVII + Pro, CP-52 spindle, manufactured by Brookfield) can be used. Specifically, the viscosity of the oil-based ink composition at 20 ° C. is preferably 10 mPa · s to 500,000 mPa · s when measured under the condition that the rotation speed is 2.5 rpm (shear rate 5 sec ⁻¹ ). More preferably, it is 10 mPa · s to 30,000 mPa · s. When the viscosity of the oil-based ink composition is within the above numerical range, it has excellent ink fluidity and dispersion stability when used in a ballpoint pen, has good ink dischargeability, and is excellent in handwriting color development and writing.

  The oil-based ink composition according to the present invention can be produced by any conventionally known method. Specifically, it can be produced by mixing the above-mentioned respective components in necessary amounts and mixing them with various agitators such as propeller agitation, homodisper, or homomixer, and various dispersers such as a bead mill.

<Writing instrument>
The oil-based ink composition of the present invention can be used for a writing instrument such as a marking pen or a ballpoint pen having a pen tip such as a fiber tip, a felt tip, a plastic tip or a ballpoint tip. Among them, the pen core is preferably a fiber tip or a felt tip in order to improve the writability on a non-permeable recording medium such as a film. Particularly, it is preferably used for a marking pen. The porosity of the pen core is preferably 50% to 80%. When the porosity of the pen core is within the above numerical range, the pigment particles are not clogged and an appropriate ink discharge amount can be maintained.

  The writing instrument of the present invention may be configured to directly fill the oil-based ink composition, or may be provided with an ink container or an ink occlusion body that can be filled with the oil-based ink composition. Further, in order to redisperse the pigment particles and the like, it is preferable that the ink container contains a stirring body such as a stirring ball for stirring the ink. Furthermore, examples of the shape of the stirring body include a spherical body and a rod-shaped body. The material of the stirrer is not particularly limited, but specific examples thereof include metals, ceramics, resins, glass, and the like. Among these, the stirring force for redispersing the pigment particles and the like is considered. If so, it is preferable to use a metal material, and from the viewpoint of cost, it is preferable to use a glass material. The agitator may be made of a plurality of materials.

  The retracting mechanism of the writing instrument of the present invention is not particularly limited, and examples thereof include a cap type having a cap that covers the pen tip, a knock type, a rotary type, and a slide type. Further, a retractable type in which the pen tip can be housed in the barrel may be used.

  Further, the ink supply mechanism in the writing instrument is not particularly limited, and, for example, (1) a mechanism including an ink guide core made of a fiber bundle or the like as an ink flow rate adjusting member, and supplying an oil-based ink composition to a pen tip, (2) A comb groove-shaped ink flow rate adjusting member is provided, a mechanism for interposing the ink flow rate adjusting member to supply the oil-based ink composition to the pen tip, and (3) A valve mechanism-based ink flow rate adjusting member for the ink-based ink composition pen. A mechanism for supplying the oil-based ink composition directly to the pen tip from a mechanism for supplying first, and (4) an ink container or a barrel provided with the pen tip.

  In one embodiment, the writing instrument is a marking pen, and the pen tip is not particularly limited and may be, for example, a fiber tip, a felt tip, a plastic tip, or the like, and the shape thereof is a bullet shape, a chisel shape, or a It may be a brush pen type or the like.

  In one embodiment, the writing instrument is a ball-point pen, and preferably a ball-point pen having an ink backflow preventer.

The present invention will be described below with reference to various examples.
<Example 1>
The following raw materials and blending amounts were mixed with stirring at room temperature for 3 hours to obtain an oil-based ink composition for a marking pen. The viscosity of the obtained oil-based ink composition was measured by an E-type rotational viscometer (DV-II + Pro, cone type rotor CPE-42, manufactured by Brookfield). Specifically, the viscosity at 20 ° C. and a shear rate of 380 sec ⁻¹ (rotational speed 100 rpm) is. The viscosity was 2.0 mPa · s and the viscosity at a shear rate of 76 sec ⁻¹ (rotational speed 20 rpm) was 2.1 mPa · s.
・ Pigment particles 20% by mass
(YInMn blue pigment particles, average particle diameter: 1.3 μm, manufactured by Shepherd Color Japan Ink, trade name: BLUE10G513)
・ Wetting dispersant 1.0% by mass
(Alkyrol ammonium salt of a copolymer containing an acid group, acid value: 94 mgKOH / g, amine value: 94 mgKOH / g, solid content: 81%, manufactured by BYK Chemie, trade name: DISPERBYK-180)
・ Ethyl alcohol 77.0% by mass
・ Ethylene glycol monophenyl ether 2.0 mass%

<Examples 2 to 11, Comparative Example 1>
Compared to Example 1, the types and addition amounts of the components to be blended were changed as shown in Tables 1 and 2 to obtain the oil-based ink compositions for marking pens of Examples 2 to 11 and Comparative Example 1. It was
<Examples 12 to 17, Comparative Example 2>
The oil-based ink compositions for ball-point pens of Examples 12 to 17 and Comparative Example 2 were obtained by changing the types of components to be blended and the amounts added in Example 1 as shown in Table 2.
The viscosity of the oil-based ink composition of Example 12 was measured with a viscometer viscometer (RVDVII + Pro, CP-52 spindle, manufactured by Brookfield). Specifically, the viscosity at 20 ° C. and a shear rate of 5 sec ⁻¹ (rotational speed 2.5 rpm) was 40.1 mPa · s.
Details of the materials used in these examples are as follows.
-ANTI-TERRA U100 (unsaturated polyaminoamide and low molecular weight polyester acid salt, acid value: 50 mgKOH / g, amine value: 35 mgKOH / g, solid content: 95%, manufactured by BYK Corporation)
-ANTI-TERRA 203 (solution of alkylammonium salt of polycarboxylic acid, acid value: 51 mgKOH / g, amine value: 51 mgKOH / g, solid content: 50%, manufactured by BYK Chemie Ltd.)
-ANTI-TERRA 204 (polycarboxylate of polyaminoamide, acid value: 41 mgKOH / g, amine value: 37 mgKOH / g, solid content: 52%, manufactured by BYK Chemie Ltd.)
-DISPERBYK-106 (polymer salt having an acidic group, acid value: 132 mgKOH / g, amine value: 74 mgKOH / g, solid content: 91%, manufactured by BYK Chemie Ltd.)
・ S-REC BL-1 (polyvinyl butyral resin, Sekisui Chemical Co., Ltd.)
Hirac 110H (ketone resin, manufactured by Hitachi Chemical Co., Ltd.)
・ Prysurf A208B (phosphate ester type surfactant, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
・ Polyvinylpyrrolidone K90 (polyvinylpyrrolidone resin, manufactured by ISPE Japan Co., Ltd.)
・ Nymeen L-201 (organic amine, NOF Corporation)
·benzyl alcohol

The redispersibility and handwriting color development of the prepared oil-based ink composition were evaluated as follows. The results obtained were as shown in Tables 1-2.
<Evaluation of redispersibility>
The oil-based ink compositions obtained in each of the examples and comparative examples were placed in a closed glass test tube having a diameter of 15 mm and left at room temperature for 14 days. Then, each glass test tube once settled was shaken up and down, and the redispersed state of the oil-based ink composition was visually observed. The aggregation state was evaluated according to the following criteria.
A: easily redispersed by shaking B: redispersed by shaking, but time consuming C: not sufficiently redispersed by shaking D: not redispersed by shaking The oil-based ink compositions obtained in Examples 12 to 17 and Comparative Example 2 were evaluated for dispersion stability, not redispersibility. When placed in a closed glass test tube having a diameter of 15 mm and left at room temperature for 14 days and then observed under a microscope as described above, the oil-based ink compositions of Examples 12 to 17 were found to have YInMn blue pigment particles uniformly dispersed. And was excellent in dispersion stability. On the other hand, in the oil-based ink composition of Comparative Example 2, YInMn blue pigment particles formed an aggregate, which had an effect on the writability.

A bullet-shaped polyester fiber core tip having a porosity of 60% is used as a pen tip, and an ink container (internal dimension: length 80 mm, diameter 16 mm) of a marking pen equipped with the pen tip is made of a metal material having a diameter of 8 mm. A spherical stirrer and the oil-based ink compositions obtained in Examples 1 to 11 and Comparative Example 1 were filled, and the pen-point was impregnated with the oil-based ink composition to obtain a marking pen.
In addition, in a refill ink containing cylinder (made of polypropylene) having a ball-point pen tip rotatably holding a cemented carbide ball having a diameter of 0.7 mm with a clearance of 40 μm from the inner surface of the ball holding portion (made of polypropylene), The oil-based ink compositions obtained in Examples 12 to 17 and Comparative Example 2 were filled, and the refill was placed in an oil-based ballpoint pen (trade name: Acroball (registered trademark)) manufactured by Pilot Corporation, and the ballpoint pen was used. Got
When the writing test paper was written with the marking pen or the ballpoint pen and visually observed, the oil-based ink compositions of each of the Examples / Comparative Examples had no scratches and had good writability.

<Evaluation of handwriting color development>
Writing was performed on a writing test paper with the above-mentioned marking pen or ballpoint pen. The color development of the handwriting at that time was visually observed. In addition, JIS P3201 Writing Paper A was used as the writing test paper.
A: Good handwriting with no color unevenness B: Some handwriting color unevenness, but practically no problem C: Handwriting uneven coloration, which is a concern in practice

Tables 1 and 2 show that the oil-based ink compositions of Examples 1 to 17 have higher ink storage stability and excellent color development of handwriting, as compared with the oil-based ink compositions of Comparative Examples 1 and 2. I found out.
Further, the oil-based ink compositions of Examples 1 to 17 were replaced with JIS P3201 Writing Paper A, which is a high-quality paper having a whiteness of 75.0, and black having a lightness of 3.0 and a saturation of 1.0. When the handwriting color development was evaluated in the same manner as above using the high-quality paper as a writing test paper, the handwriting concealed the color of the writing surface, and good handwriting was obtained.

Claims (6)

An oil-based ink composition for a writing instrument, comprising pigment particles, a dispersant, and an organic solvent, wherein the pigment particles are YInMn blue pigment particles. The oil-based ink composition for a writing instrument according to claim 1, wherein the dispersant is a wetting dispersant having an acid value and / or an amine value. The acid value of the wetting dispersant having an acid value and / or an amine value is 10 mgKOH / g to 140 mgKOH / g, and the amine value is 10 mgKOH / g to 140 mgKOH / g. The oil-based ink composition for a writing instrument as described in 1. The content of the wetting dispersant in the oil-based ink composition is 0.1% by mass to 20% by mass based on the total mass of the oil-based ink composition. An oil-based ink composition for a writing instrument. The oil-based ink composition for a writing instrument according to any one of claims 1 to 4, wherein the organic solvent is an alcohol-based organic solvent and / or a glycol ether-based organic solvent. A writing instrument containing the composition according to any one of claims 1 to 5.