阅读说明：本技术 书写工具用水性墨组合物 (Water-based ink composition for writing instrument ) 是由 羽贺久人 于 2020-03-24 设计创作，主要内容包括：提供一种使用了显色性优异的着色树脂颗粒的适用于签字笔、记号笔、圆珠笔等书写工具的书写工具用水性墨组合物。本发明的书写工具用水性墨组合物的特征在于,含有着色树脂颗粒,所述着色树脂颗粒被作为酸性染料与碱性染料的成盐体的成盐染料着色。(Disclosed is an aqueous ink composition for writing instruments, which is suitable for writing instruments such as sign pens, marker pens and ball-point pens, and which uses colored resin particles having excellent color developability. The aqueous ink composition for a writing instrument of the present invention is characterized by containing colored resin particles colored with a salt-forming dye which is a salt-forming body of an acid dye and a basic dye.)

1. An aqueous ink composition for a writing instrument, comprising colored resin particles colored with a salt-forming dye which is a salt-forming body of an acid dye and a basic dye.

2. A writing instrument comprising the aqueous ink composition for a writing instrument according to claim 1.

Technical Field

The present invention relates to an aqueous ink composition for writing instruments, which uses colored resin particles having excellent color developability and is suitable for writing instruments such as sign pens, markers, and ball-point pens.

Background

Conventionally, a resin emulsion having a specific polymer composition is dyed with a dye and used as a coloring material, also referred to as a similar pigment.

For example, there is known an aqueous ink composition for writing instruments and the like characterized by containing at least a colored resin emulsion obtained by dyeing with a dye of a dyeable resin emulsion dyed with polyoxyethylene styrenated phenyl ether (for example, see patent document 1 of the present application).

However, in the production of the colored resin particles described in patent document 1, there is no disclosure or recognition of colored resin particles using a salt-forming dye having a structure of an acid dye and a basic dye.

The colored resin particles can be colored by various dyes, but there are technical problems as follows: there is an upper limit to the amount that can be incorporated into the particles depending on the type of dye. The overall tendency is now that the upper limit of the amount of acid dye is lower. Therefore, even when an acid dye having excellent color developability is used as a colorant for colored resin particles, the properties may not be sufficiently exhibited, and colored resin particles having more excellent color developability are required.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2017-2121 (claims, examples, etc.)

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above-mentioned problems of the prior art and the current situation, and an object of the present invention is to provide an aqueous ink composition for a writing instrument suitable for a writing instrument such as a sign pen, a marker pen, a ball-point pen, etc., using colored resin particles having excellent color developability, and a writing instrument having the aqueous ink composition for a writing instrument mounted thereon.

Means for solving the problems

The present inventors have conducted extensive studies with respect to the above-mentioned conventional problems and the like, and as a result, have found that the above-mentioned aqueous ink composition for a writing instrument can be obtained without deteriorating the characteristics of an acid dye having a good color development by using a salt-forming dye having a structure of an acid dye and a basic dye, and have completed the present invention.

That is, the aqueous ink composition for a writing instrument of the present invention is characterized by containing colored resin particles colored with a salt-forming dye which is a salt-forming body of an acid dye and a basic dye.

The writing instrument of the present invention is characterized by being loaded with the aqueous ink composition for writing instruments.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention provides an aqueous ink composition for writing instruments which is suitable for writing instruments such as sign pens, marker pens, and ball-point pens and which has excellent color developability, and a writing instrument having the aqueous ink composition for writing instruments mounted thereon.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The aqueous ink composition for a writing instrument of the present invention is characterized by containing colored resin particles colored with a salt-forming dye which is a salt-forming body of an acid dye and a basic dye.

< salt-forming dye >

The salt-forming dye used in the present invention, which is a salt-forming product (salt-forming compound) of an acid dye and a basic dye, is a compound obtained by reacting an acid dye and a basic dye, and is a dye having excellent spectral characteristics and color purity of both an acid dye and a basic dye without deteriorating the characteristics of the acid dye, which is a raw material, and which develops a good color. Further, it has an advantage that the spectral adjustment of the salt-forming body can be performed by a combination of the acid dye and the basic dye.

In the present invention, unlike an inorganic salt of an acid dye having an acid group such as a sulfonate group or a carboxylate group, which is a derivative of an acid dye, an amide compound such as a salt of an acid dye and a nitrogen-containing compound, or a sulfonamide compound of an acid dye, a salt-forming compound of an acid dye and a basic dye is a compound obtained by a chemical (salt-forming) reaction of an acid dye in which a dye ion is anionic and a basic dye in which a dye ion is cationic, and therefore, the structure is extremely rigid and chemically stable.

Therefore, when a salt-forming dye comprising a salt-former compound of an acid dye and a basic dye is used as a coloring material of a colored resin particle, unlike the case of using a mixture between dyes, since it functions as a chemically stable compound, the excellent spectral characteristics and color purity each of the acid dye and the basic dye are not impaired, and a colored resin particle having excellent color developability, luminance can be obtained.

Further, since the structure is stable, the composition exhibits spectral characteristics excellent in heat resistance and light resistance. Further, since the acid dye and the basic dye have excellent spectral characteristics and color purity, respectively, without deteriorating the characteristics of the acid dye having good color development, which is a starting material for salt-forming reaction, it is possible to arbitrarily perform spectral adjustment by changing the combination of the starting materials for salt-forming reaction. Further, the salt-forming compound imparts water resistance and the like, and therefore, the dispersibility in a solvent containing water is excellent.

The acid dye used in the present invention is a water-soluble dye having an acid group such as a sulfonic acid group or a carboxyl group or a structure of a salt thereof in a dye molecule.

Among the acid dyes, some are classified as direct dyes, which are dyes having a large molecular weight and a planar structure among the acid dyes, and salt-forming compounds of the direct dyes and the basic dyes are particularly excellent in heat resistance, and are excellent in color developability and heat resistance by appropriately selecting the kind of monomers used for coloring the resin particles of the resin particles, and the like.

As direct dyes that can be used, for example: azo dyes, thiazole dyes, anthraquinone dyes, oxazine dyes, phthalocyanine dyes, and the like. Below, usable dyes are listed by color index (c.i.) numbers.

Examples of azo dyes include: c.i. direct Yellow 2, 33, 34, 35, 39, 50, 69, 70, 71, 86, 93, 94, 95, 98, 102, 109, 129, 136, 141;

C.I.Direct Orange 41，46，56，61，64，70，96，97，106，107；

C.I.Direct Red 79，82，83，84，97，98，99，106，107，172，173，176，177，179，181，182，204，207，211，213，218，221，222，232，233，243，246，250；

C.I.Direct Violet 47，52，54，60，65，66，79，80，81，82，84，89，90，93，95，96，103，104；

C.I.Direct Blue 51，57，71，81，84，85，90，93，94，95，98，100，101，113，149，150，153，160，162，163，164，166，167，170，172，188，192，193，194，196，198，200，207，209，210，212，213，214，222，228，229，237，238，242，243，244，245，247，248，250，251，252，256，257，259，260，268，274，275；

c.i. direct Green27, 34, 37, 65, 67, 68, 69, 72, 77, 79, 82, etc. Examples of thiazole dyes include: direct Yellow 54.

Examples of the oxazine dye include: c.i. direct Blue 97, 99, 106, 107, 108, 109, 190, 293, etc.

Examples of the anthraquinone-based dye include: direct Blue 77.

Examples of the phthalocyanine-based dye include: c.i. direct Vlue 86, 87, 189, 199, etc.

Other direct dyes include: c.i.direct Yellow 38, 43, 47, 58, 68, 108, 138; c.i. direct Orange 34, 39, 50, 52, 57, 65, 68; c.i. direct Red91, 92, 96, 105, 184, 220, 234, 241; c.i.direct Violet 59; c.i. direct Blue80, 114, 115, 117, 119, 137, 155, 156, 158, 159, 161, 171, 173; c.i. direct Green 25, 31, 32, 63, 66, etc.

As the acid dye other than the direct dye, azo dyes, xanthene dyes, phthalocyanine dyes, anthraquinone dyes, quinoline dyes, azine dyes, indigo dyes, and the like can be used.

Examples of azo dyes include: c.i. acid Red1, 3, 4, 6, 8, 11, 12, 14, 18, 26, 27, 33, 37, 53, 57, 88, 106, 108, 111, 114, 131, 137, 138, 151, 154, 158, 159, 173, 184, 186, 215, 257, 266, 296, 337;

C.I.Acid Orange 7、10、12、19、20、22、28、30、52、56、74、127；

C.I.Acid Violet 11、56、58；

C.I.Acid Yellow 1、6、6C、17、18、23、25、36、38、42、44、54、59、72、78、151；

C.I.Acid Brown 2、4、13、248；

c.i. acid Blue 92, 102, 113, 117, etc.

Examples of the xanthene-based dye include: c.i. acid Red 50, 51, 52, 87, etc.

Examples of the phthalocyanine-based dye include: c.i.acid Blue 249.

Examples of the anthraquinone-based dye include: c.i.acid Red 82, 92; c.i.acid Violet 41, 42, 43; c.i. acid Blue 14, 22, 25, 40, 45, 78, 80, 127: 1. 129, 145, 167, 230; c.i. acid Green 25, 27, etc.

Examples of quinoline dyes include: c.i.acid Yellow 3.

Examples of azine-based dyes include: c.i. acid Blue 59, 102, etc.

Examples of the indigo dye include: c.i.acid Blue 74.

As other dyes, there may be mentioned: c.i.acid Violet 49; acid Brown 19; c.i. acid Blue 7, 9, 74, 112, 126, 167; c.i. acid Green 9, and the like.

The basic dye used in the present invention is a dye having a structure of a basic group such as an amino group, an imino group or the like or a salt thereof in a molecule and becoming a cation in an aqueous solution.

Examples of the basic dye that can be used include: diarylmethane and triarylmethane-based dyes; quinone imine dyes such as azine-based (including nigrosine), oxazine-based, and thiazine-based dyes; a xanthene-based dye; a triazole azo-based dye; a thiazole azo dye; a benzothiazole azo-based dye; azo dyes; methine dyes such as polymethine dyes, azomethine dyes and azamethine dyes; an anthraquinone-based dye; a phthalocyanine-based dye; at least one of basic dyes such as acridine dyes, rhodamine dyes, triarylmethane dyes, etc., preferably water-soluble basic dyes.

Examples of specific yellow basic dyes that can be used include: dyes described in COLOR INDEX of c.i. basic Yellow1, 2, 9, 11, 12, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 33, 34, 35, 36, 40, 41, 51, 63, 73, 80, and the like. Further, examples of commercially available YELLOW basic dyes include AIZEN CATHILON YELLOW GPLH, Spilon YELLOW C-GNH-new (trade name manufactured by Baoku chemical industries, Ltd.).

Examples of orange basic dyes include: dyes described in COLOR INDEX, such as c.i. basic Orange 1,2, 7, 14, 15, 21, 22, 23, 24, 25, 30, 32, 33, 34.

Examples of red basic dyes include: basic Red (Basic Red) -1, -2, -3, -4, -8, -9, -12, -13, -14, -15, -16, -17, -18, -22, -23, -24, -25, -26, -27, -29, -30, -32, -34, -35, -36, -37, -38, -39, -40, -41, -42, -43, -46, -49, -50, -51, -52, -53, and other COLOR INDEX dyes. Further, examples of commercially available red basic dyes include: AIZEN CATHILON RED BLH, AIZEN CATHILON RED RH, etc. (trade names manufactured by KETUO GAUGAI chemical Co., Ltd.), Diacryl super Brilliant Red 2G, etc. (trade names manufactured by Mitsubishi chemical Co., Ltd.), Sumiacryl Red B, etc.

Examples of violet basic dyes include: c.i. basic Violet 1,2,3, 4, 5,6, 7, 8, 10,11, 11: 1, 12, 13, 14, 15, 16, 18, 21, 23, 24, 25, 26, 27, 28, 29, 33, 39, and the like.

Examples of blue basic dyes include: a dye described in COLOR INDEX of c.i. basic Blue1, 2,3,5,6, 7, 8, 9, 15, 18, 19, 20, 21, 22, 24, 25, 26, 28, 29, 33, 35, 37, 40, 41, 42, 44, 45, 46, 47, 49, 50, 53, 54, 58, 59, 60, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 75, 77, 78, 79, 82, 83, 87, 88, etc. Examples of commercially available BLUE basic dyes include AIZEN CATHILON TURQUOISE BLUE LH (trade name manufactured by KETTLE CHEMICAL INDUSTRIAL Co., Ltd.).

Examples of the green basic dye include: dyes described in COLOR INDEX such as c.i. basic Green 1,4, 6, 10, etc. Further, examples of commercially available green basic dyes include: diacryl super Brilliant Green 2GL (trade name manufactured by Mitsubishi chemical corporation), and the like.

Examples of brown basic dyes include: dyes described in COLOR INDEX of c.i. basic Brown 1,2, 4, 5, 7, 11, 12, 13, 15. Further, commercially available brown basic dyes include: janus Brown R (trade name manufactured by Nippon chemical Co., Ltd.), AIZEN CATHILON BROWN GH (trade name manufactured by Baoku chemical industry Co., Ltd.), and the like.

Examples of the black basic dye include: dyes described in COLOR INDEX such as c.i. basic Black1, 2,3, 7, 8, etc., or nigrosine-based basic dyes.

In the present invention, a known method can be applied as a method for producing a salt-forming dye of a salt-forming product of an acid dye and a basic dye. For example, an aqueous acid dye solution and an aqueous basic dye solution are prepared, mixed and stirred, and then, a salt-forming body is filtered, and the collected precipitate is dried to obtain a predetermined salt-forming dye.

In addition, when producing the colored resin particles, the preparation of the salt-forming body and the synthesis of the colored resin particles may be continuously performed by mixing the acid dye and the basic dye.

In the present invention, the salt-forming dye comprising a salt-forming compound of a direct dye and a basic dye may be used alone, or a salt-forming dye comprising 2 or more salt-forming compounds may be used in combination.

In the present invention, a commercially available salt-forming dye which is a salt-forming product of an acid dye and a basic dye may be used, and further, a salt-forming dye synthesized from a commercially available acid dye and a basic dye may be used.

Commercially available products include: VALIFAST RED 1308 (salt former of c.i. acid Yellow 23 and c.i. basic Red 1), VALIFAST RED1320 (salt former of c.i. acid Yellow 42 and c.i. basic Red 1), VALIFAST RED 1355, VALIFAST RED 1388 (both salt formers of c.i. acid Yellow 23 and c.i. basic Red 1), VALIFAST GREEN 1501: (salt-forming product of C.I. acid Yellow 42 and C.I. basic Blue 1), VALIFAST VIOLET 1701 (salt-forming product of C.I. acid Yellow 42 and C.I. basic Violet 1), VALIFAST VIOLET 1704 (salt-forming product of C.I. acid Yellow 36 and C.I. basic Violet 1), and a salt-forming dye synthesized from a commercially available product (salt-forming dye of Water Yellow 6C (manufactured by organic Chemical Industries: C.I. acid Yellow 6C) and Spilon Yellow C-GNH-new (manufactured by soil conservation Chemical Co., Ltd., basic dye)), salt-forming dyes of C.I. acid Blue 9 and Spilon Yellow C-GNH-new (manufactured by soil conservation Chemical Co., Ltd.), and salt-forming dyes of C.I. acid Blue 9 and C.I. basic Blue 1.

< colored resin particles >

In the present invention, the colored resin particles are resin particles colored with a salt-forming dye which is a salt-forming product of the acid dye and the basic dye, and examples thereof include: the acrylic resin particles, the vinyl acetate resin particles, the urethane resin particles, the styrene-butadiene resin particles, and the styrene acrylonitrile resin particles are colored with a salt-forming dye which is a salt-forming product of the acid dye and the basic dye, and examples thereof include various colored resin particles composed of at least one of raw material monomers of each of acrylic, vinyl acetate, urethane, styrene-butadiene, and styrene acrylonitrile, and a salt-forming dye which is a salt-forming product of the acid dye and the basic dye.

Examples of the acrylic colored resin particles colored with a salt-forming dye include at least: colored resin particles comprising a vinyl monomer having a solubility in water of 10 mass% or less and containing a carboxyl group as an acidic functional group, an ester monomer of acrylic acid or methacrylic acid and a linear or cyclic alcohol having 2 to 18 carbon atoms, and a salt-forming dye which is a salt-forming product of the acidic dye and a basic dye.

The vinyl monomer having a carboxyl group as an acidic functional group and a solubility in water of 10% by mass or less is not particularly limited as long as it is a color-developing monomer, has a solubility in water of 10% by mass or less, and has an acidic functional group of a carboxyl group, and examples thereof include: 2-Methacryloyloxyethyl succinate [ manufactured by Mitsubishi Yang corporation, acrylate SA, solubility in water: 1.86% by mass ] 2-methacryloyloxyethyl maleate [ acrylic ester ML, water solubility, manufactured by Mitsubishi corporation: 9.17% by mass ] 2-methacryloyloxyethyl phthalate [ acrylic ester PA, available from Mitsubishi corporation, solubility in water: 0.08% by mass, 2-methacryloyloxyethyl hexahydrophthalate [ manufactured by Mitsubishi corporation, acrylate HH, solubility in water: 3.40 mass% ] and the like. In particular, it is preferable to use 2-methacryloyloxyethyl hexahydrophthalate from the viewpoint of providing compatibility with a salt-forming dye which is a salt former of the acid dye and the basic dye and further sufficient color developability.

When the carboxyl group-containing vinyl monomer having a solubility in water of 10 mass% or less is used, the ratio of the acid monomer in the mixed monomer with the ester monomer can be increased, and thus the amount of the salt-forming dye which is a salt-forming product of the acid dye and the basic dye that can be mixed with the vinyl monomer is extremely large, and as a result, colored resin particles having a color depth and excellent color developability due to the salt-forming dye can be obtained.

The ester monomer of acrylic acid or methacrylic acid and a linear or cyclic alcohol having 2 to 18 carbon atoms is a backbone monomer, and is an ester of acrylic acid or methacrylic acid and a linear or cyclic alcohol having 2 to 18 carbon atoms, and specifically, it can be suitably represented by: at least one of ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, and the like. The "(meth) acrylic acid" symbol represents "acrylic acid and/or methacrylic acid".

It is particularly preferable to use n-butyl (meth) acrylate, lauryl methacrylate, and cyclohexyl methacrylate for further improving the line drying property.

The acrylic colored resin particles colored with the salt-forming dye can be produced by dispersing in water at least colored resin particles comprising a vinyl monomer having a solubility of 10 mass% or less in water and containing a carboxyl group as an acidic functional group, an ester monomer of the acrylic acid or methacrylic acid and a linear or cyclic alcohol having 2 to 18 carbon atoms, and a salt-forming dye which is a salt-forming product of the acidic dye and the basic dye to obtain an aqueous dispersion, and drying the aqueous dispersion. In addition, an aqueous dispersion of the above-mentioned colored resin particles can also be used as the aqueous ink composition for a writing instrument of the present invention.

As a specific method for producing the above-mentioned resin composition, for example, the following can be produced: and (b) dissolving the salt-forming dye, which is a salt-forming product of the acid dye and the basic dye, in a mixed monomer comprising the vinyl monomer having a solubility in water of 10 mass% or less, which contains a carboxyl group as an acid functional group, and the ester monomer of acrylic acid or methacrylic acid and a linear or cyclic alcohol having 2 to 18 carbon atoms, and performing emulsion polymerization using ammonium persulfate, potassium persulfate, hydrogen peroxide, or the like as a polymerization initiator, or further using a polymerization initiator of a reducing agent in combination, and further using a polymerizable surfactant as necessary. The dyeing and polymerization are carried out simultaneously, but the dyeing may be carried out by dissolving the salt-forming dye after the polymerization.

In the emulsion polymerization, a dicyclopentadienyl (meth) acrylate monomer may be further mixed with the carboxyl group-containing vinyl monomer component, the ester of acrylic acid or methacrylic acid and a linear or cyclic alcohol having 2 to 18 carbon atoms, and emulsion polymerization may be carried out. This is because a polymer obtained by further mixing the above-mentioned dicyclopentadienyl (meth) acrylate monomer and emulsion-polymerizing the monomer is less likely to impair the stability even when water in the dispersion is volatilized, and a dispersion of colored resin particles having more excellent stability and a water-based ink composition for writing instruments can be obtained.

The dicyclopentadienyl (meth) acrylate monomer includes dicyclopentanyl acrylate monomer, dicyclopentenyl methacrylate monomer, and dicyclopentenyl methacrylate monomer.

In addition, in the emulsion polymerization, other hydrophobic vinyl monomers may be mixed in addition to the above components and emulsion polymerization may be performed. The hydrophobic vinyl monomer to be used is not particularly limited, and examples thereof include: styrenes such as styrene and methylstyrene. In addition, in the emulsion polymerization, a monomer having a reactive crosslinking group such as an epoxy group, a methylolamide group, an isocyanate group, or the like, or a polyfunctional monomer having two or more vinyl groups may be blended and crosslinked.

In the present invention, the total content of the carboxyl group-containing vinyl monomer and the ester monomer in the polymer components constituting the colored resin particles is preferably 60% by mass or more, more preferably 70% by mass or more and 100% by mass in the polymer composition, from the viewpoint of improving the line-drawing dryness, in addition to the functions as a coloring material such as color developability, weather resistance, stability, and the like. Particularly, the content of the carboxyl group-containing vinyl monomer is preferably 40% by mass or more and the content of the ester monomer is preferably 20% by mass or more.

When the dicyclopentadienyl (meth) acrylate monomer is further used as the polymer component constituting the colored resin particles, the content thereof is 1 to 25% by mass, more preferably 5 to 15% by mass, from the viewpoint of stability and further improvement of ink performance.

In the present invention, the content of the salt-forming dye is preferably 0.2 to 50% by mass, more preferably 0.5 to 10% by mass, based on the total amount of the monomers, from the viewpoint of the function as a coloring material such as color developability, weather resistance, and stability.

The polymerizable surfactant that can be used as needed is not particularly limited as long as it is a polymerizable surfactant that is generally used in the emulsion polymerization, and examples of the polymerizable surfactant include anionic or nonionic polymerizable surfactants: at least 1 kind of material selected from ADEKA REASOAP NE-10, ADEKAREASOAP NE-20, ADEKA REASOAP NE-30, ADEKA REASOAP NE-40, ADEKA REASOAP SE-10N, LATEMUL S-180A, LATEMUL S-120A, and Eleminol JS-20 manufactured by Sanyo chemical industries, Ltd. The amount of the polymerizable surfactant is 0 to 50% by mass, preferably 0.1 to 50% by mass, based on the total amount of the monomers.

With the above preferred embodiment, specifically, at least the salt-forming dye as described above is dissolved in the mixed monomer containing 40 mass% or more of the above carboxyl group-containing vinyl monomer and 20 mass% or more of the above ester monomer to carry out emulsion polymerization; or at least dissolving a salt-forming dye after the polymerization and dyeing the resulting dispersion to disperse the colored resin particles in water in an amount of 20 to 50 mass% based on the resin solid content to obtain a dispersion of the colored resin particles, and drying the dispersion to obtain the colored resin particles. When the aqueous ink composition is used for an aqueous ink composition for a writing instrument, the dispersion of the colored resin particles obtained as described above can be used as it is.

Although the acrylic colored resin particles are described in detail above, the colored resin particles each composed of the monomer raw material and the salt-forming dye, which is a salt of the acid dye and the basic dye, can be produced even from the vinyl acetate colored resin particles, the urethane colored resin particles, the styrene-butadiene colored resin particles, and the styrene acrylonitrile colored resin particles.

The obtained colored resin particles have unprecedented excellent color developability and are useful as a coloring material for an aqueous ink composition for writing instruments suitable for writing instruments such as sign pens, marker pens, and ball-point pens.

In the present invention, the average particle diameter of the obtained colored resin particles varies depending on the kind and content of each monomer, polymerization conditions during polymerization, and the like, but is 1 μm or less, and clogging does not occur in the writing core of a writing instrument such as a sign pen, a marker pen, a ballpoint pen, and the like. In the present invention, the "average particle diameter" refers to a value of the particle diameter (D50) at 50% volume accumulation of a particle diameter distribution calculated on a volume basis measured by a laser diffraction method. The average particle size can be measured by a laser diffraction method, and can be measured, for example, using a particle size distribution analyzer HRA9320-X100, manufactured by japan ltd.

< aqueous ink composition for writing instruments >

The aqueous ink composition for a writing instrument of the present invention contains the colored resin particles colored with the salt-forming dye which is a salt-forming product of the acid dye and the basic dye, and preferably further contains a water-soluble organic solvent and water.

The content of the colored resin particles varies depending on the kind of writing instrument such as a sign pen, a marker pen, a ball-point pen, etc., and is preferably 0.1 to 30.0% by mass, more preferably 0.5 to 20.0% by mass, based on the resin solid content, relative to the total amount of the ink composition.

Examples of the water-soluble organic solvent that can be used include: ethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 2, 3-butanediol, 1, 4-butanediol, 1, 2-pentanediol, 1, 5-pentanediol, 2, 5-hexanediol, 3-methyl-1, 3-butanediol, 2-methylpentane-2, 4-diol, 3-methylpentane-1, 3, 5-triol, alkylene glycols such as 1,2, 3-hexanetriol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, glycerin, etc., lower alkyl ethers of ethylene glycol such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol mono-n-butyl ether, etc., lower alkyl ethers of ethylene glycol such as ethylene glycol, triethylene glycol monoethyl ether, diethylene glycol monoethyl ether and diethylene glycol mono-n-butyl ether, etc, At least 1 kind of N-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, etc.

Further, for example: water-soluble solvents such as alcohols such as methanol, ethanol, isopropanol, n-butanol, t-butanol, isobutanol, hexanol, octanol, nonanol, decanol, and benzyl alcohol, amines such as dimethylformamide and diethylacetamide, and ketones such as acetone.

The content of the water-soluble organic solvent varies depending on the type of writing instrument such as a sign pen, a marker pen, a ball-point pen, etc., and is 1 to 40% by mass based on the total amount of the ink composition, and is particularly effective for an ink composition of 10% by mass or less, and more preferably 3 to 8% by mass, from the viewpoint of further improving the line drying property.

The content of water (tap water, purified water, ion-exchanged water, distilled water, purified water, etc.) is preferably 30 to 90% by mass, and more preferably 40 to 60% by mass, based on the total amount of the ink composition.

In the aqueous ink composition for a writing instrument of the present invention, a preservative or a mildewcide, a pH adjuster, an antifoaming agent, a dispersant, and the like may be appropriately selected and used as needed depending on the type of the writing instrument and within a range not to impair the effects of the present invention.

Examples of the pH adjuster include: and at least one of carbonic acids such as ammonia, urea, monoethanolamine, diethanolamine, triethanolamine, aminomethylpropanol, sodium tripolyphosphate, and sodium carbonate, alkali metal salts of phosphoric acids, and hydroxides of alkali metals such as sodium hydroxide.

Examples of the preservative or the antifungal agent include: at least one of phenol, sodium olmesartan, sodium pentachlorophenolate, 1, 2-benzisothiazolin 3-one, 2,3,5, 6-tetrachloro-4 (methylsulfonyl) pyridine, alkali metal salts of benzoic acid, sorbic acid, dehydroacetic acid, benzimidazole compounds, and the like.

Examples of the lubricant include: and at least one member selected from polyalkylene glycol derivatives such as phosphoric acid esters and polyoxyethylene lauryl ether, fatty acid alkali salts, nonionic surfactants, fluorine surfactants such as perfluoroalkyl phosphate esters, and polyether-modified silicones such as polyethylene glycol adducts of dimethylpolysiloxane.

The aqueous ink composition for a writing instrument of the present invention configured as described above contains the colored resin particles or the dispersion thereof colored with the salt-forming dye which is a salt-forming product of the acid dye and the basic dye and having excellent color developability, and therefore, the aqueous ink composition for a writing instrument suitable for a writing instrument such as a sign pen, a marker pen, a ballpoint pen, or the like can be obtained.

< writing tools >

The writing instrument of the present invention is characterized by being equipped with the aqueous ink composition for writing instruments having the above-described configuration.

Specifically, the aqueous ink composition for writing instruments having the above-described configuration is mounted on a ballpoint pen, a marker pen, or the like having a tip portion such as a ballpoint pen tip, a fiber tip, a felt tip, a plastic tip, or the like.

Examples of the ballpoint pen include: a pen in which the aqueous ink composition for a writing instrument having the above-mentioned composition is contained in an ink container (refill) for a ballpoint pen having a ball with a diameter of 0.18 to 2.0mm, and a substance which is incompatible with the aqueous ink composition contained in the ink container and has a small specific gravity relative to the aqueous ink composition, for example, polybutene, silicone oil, mineral oil, or the like, is contained as an ink follower.

The structure of the ball-point pen and marker pen is not particularly limited, and for example, a straight-liquid ball-point pen and marker pen having the following structure may be used: the container itself is used as an ink container, and the container is filled with the above-described aqueous ink composition for a writing instrument.

In the writing instrument thus constituted, since the above-mentioned water-based ink composition for writing instrument having excellent color developability is mounted, it is possible to obtain a writing instrument such as a sign pen, a marker pen, a ball-point pen, etc., which has excellent color developability and is bright in a desired color (yellow, red, blue, black, etc.).

Examples

Next, the present invention will be described in more detail by way of examples of producing a salt-forming dye and a colored resin particle, examples of an aqueous ink composition for a writing instrument, and comparative examples, but the present invention is not limited to the following examples and the like.

Production example 1

In the production of the colored resin particles described below, the preparation of a salt-forming body (salt-forming dye) and the synthesis of the colored resin particles are continuously performed by mixing an acid dye and a basic dye, thereby obtaining the colored resin particles 1.

A2-liter flask was equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen introduction tube, and a 1000-ml separatory funnel to which a monomer was added, and the flask was placed in a warm water tank, and 500g of distilled water, 50g of a polymerizable surfactant (manufactured by ADEKA, "ADEKA REASOAP SE-10N" ] and 3g of ammonium persulfate were added to the flask, and the internal temperature was raised to 50 ℃ while introducing nitrogen.

On the other hand, in the case of a copolymer prepared from 2-methacryloyloxyethyl phthalate [ acrylate PA, manufactured by Mitsubishi corporation, solubility in water: 0.08% by mass 300g of a mixed monomer containing 200g of n-butyl methacrylate, and 20g of Water Yellow 6C (manufactured by organic Chemical Industries, Ltd.) as an Acid dye and 25g of Spilon Yellow C-GNH-new (manufactured by Bakkaido Chemical Co., Ltd.) as a basic dye were mixed with 500g of the mixed monomer to prepare a liquid.

This preparation solution was added from the separatory funnel to the flask maintained at a temperature of about 50 ℃ for 3 hours under stirring, and emulsion polymerization was carried out. The polymerization was terminated by further aging for 5 hours, to obtain a dispersion of colored resin particles.

Production example 2

In production example 1, the acid dye was replaced with c.i. acid Blue 9: 20g of the basic dye was replaced with 25g of Spilon Yellow C-GNH-new (manufactured by Kakkaido Kabushiki Kaisha), and colored resin particles 2 were obtained in the same manner as in production example 1.

(production example 3)

In the above production example 1, the acid dye was replaced with c.i. acid Yellow 42: 18g, replacement as basic dye with c.i. basic Violet 1: 22g, colored resin particles 3 were obtained in the same manner as in production example 1 described above.

Production example 4

In production example 1, VALIFAST RED 1308 g (salt-forming product of C.I. Acid Yellow 23 and C.I. basic Red 1) of original Chemical Industries was used as a salt-forming dye in place of 20g of an Acid dye (Water Yellow 6C (manufactured by original Chemical Industries, Inc.: Acid Yellow 6C)) and 25g of a basic dye [ Spilon Yellow C-GNH-new (manufactured by Bakkaido Chemical Co., Ltd.) ] to obtain colored resin particles 4 in the same manner as in production example 1.

Production example 5

In production example 4, the amount of the salt-forming dye was changed to VALIFAST RED1320 (salt-forming product of c.i. acid Yellow 42 and c.i. basic Red 1) 45g manufactured by origin Chemical Industries, and colored resin particles 5 were obtained in the same manner as in production example 4.

(production example 6)

In production example 4, VALIFAST GREEN 1501 (salt former of c.i. acid Yellow 42 and c.i. basic Blue 1) 45g was substituted as a salt-forming dye by origin Chemical Industries, and colored resin particles 6 were obtained in the same manner as in production example 4.

Production example 7

In production example 4, 45g of VALIFAST VIOLET 1701 (salt former of C.I. acid Yellow 42 and C.I. basic Violet 1) manufactured by Orient Chemical Industries was substituted for the salt-forming dye, and colored resin particles 7 were obtained in the same manner as in production example 4.

Production example 8

In production example 4, 45g of VALIFAST VIOLET 1704 (a salt former of C.I. acid Yellow 36 and C.I. basic Violet 1) manufactured by Orient Chemical Industries was substituted for the salt-forming dye, and colored resin particles 8 were obtained in the same manner as in production example 1.

Comparative production example 1

In production example 1, colored resin particles 9 were obtained in the same manner as in production example 1, except that 25g of a basic dye [ Spilon Yellow C-GNH-new (manufactured by UK Corp.) ] was used and 40g of an Acid dye (Water Yellow 6C (manufactured by organic Chemical Industries: Acid Yellow 6C) ] was used.

Comparative production example 2

In production example 2, colored resin particles 10 were obtained in the same manner as in production example 2, except for using 25g of basic dye [ Spilon Yellow C-GNH-new (manufactured by Katsuoki Kabushiki Kaisha) ] and using 945 g of acid dye C.I.acid Blue.

Comparative production example 3

In production example 3, the basic dye [ c.i. basic violet 1] 22g was not used, and the acid dye c.i. acid Yellow 42: 45g, colored resin particles 11 were obtained in the same manner as in production example 3 described above.

Comparative production example 4

In the above production example 4, the salt-forming dye (VALIFAST RED 1308) was replaced with the acid dye c.i. acid Yellow 23: 45g, colored resin particles 12 were obtained in the same manner as in production example 4 described above.

Comparative production example 5

In the above production example 8, the salt-forming dye (valinstant VIOLET 1704) was replaced with the acid dye c.i. acid Yellow 36: 45g, colored resin particles 13 were obtained in the same manner as in production example 8 described above.

(examples 1 to 8 and comparative examples 1 to 5: preparation of Water-based ink composition for writing instruments)

Using the dispersions of the colored resin particles obtained in production examples 1 to 8 and comparative production examples 1 to 5, aqueous ink compositions for writing instruments were prepared by a conventional method according to the following formulation.

The dispersion liquid of the colored resin particles for aqueous ink has an average particle diameter of 30 to 500nm and a resin solid content of 30 mass%.

(compounding composition)

With respect to each of the obtained aqueous ink compositions for writing instruments (total 100% by mass), a marker as a writing instrument was prepared by the following method, and color developability was evaluated by the following evaluation method.

The evaluation results of examples 1 to 8 and comparative examples 1 to 5 are shown in table 1 below.

(preparation of writing instruments: marking pens)

Each of the ink compositions produced in examples 1 to 8 and comparative examples 1 to 5 was loaded into a marking pen (product name: PROPUS WINDOW PUS-102T, pen point, coarse: PE resin, fine: PET fiber ] make marker.

(method of evaluating color rendering Property)

The marking pens containing the ink compositions prepared in examples 1 to 8 and comparative examples 1 to 5, which were obtained as described above, were written on PPC paper and evaluated according to the following evaluation criteria.

Evaluation criteria:

a: high concentration color development

B: colour development at slightly lower concentrations

C: light concentration or incomplete coloration

[ Table 1]

As is clear from the examination of Table 1, the water-based ink compositions for writing instruments having excellent color developability were obtained in examples 1 to 8 within the scope of the present invention as compared with comparative examples 1 to 5 not within the scope of the present invention.

Industrial applicability

An aqueous ink composition for writing instruments suitable for writing instruments such as sign pens, marking pens and ball-point pens can be obtained.