JP4670259B2 - Ink composition for inkjet recording - Google Patents

Description

  The present invention relates to an ink composition for ink jet recording. According to the ink composition for ink jet recording of the present invention, an ink composition for ink jet recording excellent in reliability at the time of printing and excellent in image quality is provided.

  In ink jet recording inks, water-based pigment inks containing pigments as colorants are widely used in order to improve light resistance and water resistance. However, it has been pointed out that such a water-based pigment ink not only has insufficient fixability to paper or an OHP sheet, but also needs to be improved in terms of water resistance of printed matter, printing characteristics, ink bleeding, and the like.

In order to solve the above-mentioned problems, for example, an emulsion of a polymer obtained by sulfonation of a (co) polymer containing a diene monomer as a constituent unit is contained together with a dye or a pigment, thereby allowing ink bleeding and water resistance. A water-based ink for ink-jet recording is known (Patent Document 1).
In addition, water-based ink for ink-jet recording that contains a sulfonic acid group-containing polymer and a carboxylic acid group-containing polymer and has good print quality and storage stability, excellent light resistance and water resistance, and no bleeding. Is also known (Patent Document 2).
Japanese Patent Laid-Open No. 11-217525 JP 2000-154343 A

However, in the recorded matter obtained by the water-based pigment ink for inkjet recording containing the sulfonic acid group-containing polymer like the inks described in Patent Document 1 and Patent Document 2, it is exposed to air for a long time. A phenomenon that white powder-like spots occur in a recorded image may occur, and no means for solving this phenomenon has been proposed in the prior art.
In addition, in the above-described aqueous pigment ink for ink-jet recording, there are many problems in printing stability such as flying bending of ink droplets during printing or clogging in the nozzle head of a printer. The recorded matter also has problems in terms of image quality, such as uneven glossiness and a recorded matter having poor abrasion resistance.
Accordingly, an object of the present invention is to prevent a white powder-like spot from appearing in a recorded image even when a recorded matter obtained with an aqueous pigment ink for ink-jet recording is exposed to air for a long period of time. An object of the present invention is to provide an ink composition that is excellent in stability, does not cause clogging of the nozzle head, has no gloss unevenness in the recorded material, and can obtain a recorded material excellent in abrasion resistance.

The above problem is in accordance with the present invention,
(A) fine particles made of a resin having a glass transition point of 10 ° C. or higher, (b) fine particles made of a resin having a glass transition point of 0 ° C. or lower, and (c) fine particles made of a sulfonated resin. This can be solved by the ink composition for ink jet recording.

In a preferred embodiment of the ink composition according to the present invention, the pigment is contained in an amount of 1% by weight or less based on the total weight of the ink composition.
In another preferred embodiment of the ink composition according to the present invention, the total amount of the resin fine particles (a), the resin fine particles (b), and the resin fine particles (c) is 1% by weight or more of the total weight of the ink composition. It is.
In still another preferred embodiment of the ink composition according to the present invention, the total amount of the resin fine particles (a) and the resin fine particles (b) is 6% by weight or less of the total weight of the ink composition.
In still another preferred embodiment of the ink composition according to the present invention, the resin fine particles (a), the resin fine particles (b), or the resin fine particles (c) are contained in the form of an aqueous emulsion.
In still another preferred embodiment of the ink composition according to the present invention, the glass transition point of the resin constituting the resin fine particles (a) is 10 ° C. or higher and 150 ° C. or lower.
In still another preferred embodiment of the ink composition according to the present invention, the glass transition point of the resin constituting the resin fine particles (b) is 0 ° C. or lower and −80 ° C. or higher.
In still another preferred embodiment of the ink composition according to the present invention, the resin constituting the resin fine particles (c) includes a sulfonic acid group-containing diene-based repeating unit and a sulfonic acid group-free vinyl-based repeating unit. The copolymer has a molar content of the sulfonic acid group-containing diene-based repeating unit in the copolymer of 5 to 90 mol%.
The present invention also relates to an ink jet recording method characterized by using the ink composition for ink jet recording, and a recorded image obtained using the ink composition for ink jet recording.

  According to the ink composition of the present invention, even if the recorded matter is exposed to the air for a long period of time, a phenomenon that white powder-like spots are not generated in the recorded image does not occur, and the print head has excellent printing stability, and the nozzle head. Clogging does not occur, and there is no uneven glossiness in the recorded material, and a recorded material excellent in abrasion resistance can be obtained.

  The resin fine particles (a) having a glass transition point of 10 ° C. or higher used in the ink composition of the present invention (hereinafter, also referred to as “high Tg resin fine particles (a)”) are not formed into a film at room temperature, whereby a recording medium is obtained. The effect of preventing the phenomenon that the resin remains in the form of solid or fine particles and the pigment permeates on the recording medium is exhibited, thereby increasing the OD value. The glass transition point (Tg) of the resin fine particles (a) is 10 ° C. or higher as described above, and is preferably 10 ° C. or higher and 150 ° C. or lower, particularly 20 ° C. in order to effectively exhibit the effect. The temperature is preferably 150 ° C. or lower.

  The resin fine particles (b) having a glass transition point of 0 ° C. or less used in the ink composition of the present invention (hereinafter also referred to as “low Tg resin fine particles (b)”) spread the resin on the recording medium, and the coloring material. Can be fixed on the recording medium. The glass transition point (Tg) of the resin fine particles (b) is 0 ° C. or less as described above. However, in order to effectively exhibit the effect, it is preferably 0 ° C. or less and minus 80 ° C. or more, particularly minus It is preferable that it is 10 degrees C or less minus 80 degrees C or more.

In addition, in this specification, a glass transition point (Tg) is a numerical value which can be measured using thermal analyzers, such as a normal method, for example, a differential scanning calorimeter (DSC). An example of the thermal analyzer is SSC5000 manufactured by Seiko Electronics. The glass transition point (Tg) can be evaluated as a calculated value of the glass transition point when the resin is a copolymer. The glass transition point (Tg) of the copolymer and the methodology for its evaluation are as follows.
The glass transition point (Tg) of a copolymer having a specific monomer composition can be determined by calculation using the Fox equation. Here, the Fox formula is for calculating the Tg of the copolymer based on the Tg of the homopolymer of the monomer for each monomer forming the copolymer, Details thereof are described in Bulletin of the American Physical Society, Series 2, Vol. 1, No. 3, page 123 (1956). The concept of the term “calculated glass transition point” used in the present specification includes a glass transition point calculated by the Fox equation. For example, the Tg of the homopolymer of various monomers serving as the basis for calculating the Tg of the copolymer according to the Fox formula is, for example, Polymer Data Handbook Fundamentals (Edition of Polymer Society) 525-546. The numerical value described on the page or the actual measurement value measured by a normal method can be adopted.

  Examples of the resin that can be applied to the high Tg resin fine particles (a) and the low Tg resin fine particles (b) in the ink composition of the present invention include acrylic resins, urethane resins, epoxy resins, and polyolefin resins. Yes, but not particularly limited. These resins are used in one kind or two or more kinds in use, and the high Tg resin fine particles (a) and the low Tg resin fine particles (b) may be combined with resins of the same system or different systems, At least one of the high Tg resin fine particles (a) and the low Tg resin fine particles (b) is an ink in the form of an emulsion (for example, so-called “acrylic emulsion”) of resin fine particles obtained by emulsion polymerization of an unsaturated monomer. It is preferable to mix | blend in a composition. The reason for this is that even if the resin fine particles are added as they are to the ink composition, the dispersion of the resin fine particles may be insufficient, so that the emulsion form is preferable for the production of the ink composition. The emulsion is preferably an acrylic emulsion from the viewpoint of storage stability of the ink composition.

  An emulsion of resin fine particles (such as an acrylic emulsion) can be obtained by a known emulsion polymerization method. For example, an unsaturated monomer (such as an unsaturated vinyl monomer) can be obtained by emulsion polymerization in water in which a polymerization initiator and a surfactant are present.

  Examples of unsaturated monomers include acrylic acid ester monomers, methacrylic acid ester monomers, aromatic vinyl monomers, vinyl ester monomers, vinyl cyanide compounds generally used in emulsion polymerization. Examples thereof include monomers, halogenated monomers, olefin monomers, and diene monomers. Furthermore, specific examples include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, decyl acrylate. , Acrylic acid esters such as dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, or glycidyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, Isoamyl methacrylate, n-hexyl methacrylate, 2-d Ruhexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, methacrylic esters such as phenyl methacrylate, benzyl methacrylate, or glycidyl methacrylate, and vinyl esters such as vinyl acetate; acrylonitrile, methacrylonitrile, etc. Vinyl cyanide compounds; halogenated monomers such as vinylidene chloride or vinyl chloride; aromas such as styrene, α-methylstyrene, vinyltoluene, 4-t-butylstyrene, chlorostyrene, vinylanisole, or vinylnaphthalene Group vinyl monomers; olefins such as ethylene or propylene; dienes such as butadiene or chloroprene; vinyl ether, vinyl Vinyl monomers such as nyl ketone or vinyl pyrrolidone; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid or maleic acid; acrylamide, methacrylamide or N, N′-dimethylacrylamide Acrylamides; hydroxyl-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, or 2-hydroxypropyl methacrylate can be used, and these can be used alone or in combination of two or more. Can be used.

  A crosslinkable monomer having two or more polymerizable double bonds can also be used. Examples of the crosslinkable monomer having two or more polymerizable double bonds include polyethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, 1,9-nonanediol diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4-acryloxypropyloxyphenyl) propane, or 2,2 Diacrylate compounds such as' -bis (4-acryloxydiethoxyphenyl) propane, triacrylates such as trimethylolpropane triacrylate, trimethylolethane triacrylate, or tetramethylolmethane triacrylate Compounds, tetraacrylate compounds such as ditrimethylol tetraacrylate, tetramethylol methane tetraacrylate, or pentaerythritol tetraacrylate, hexaacrylate compounds such as dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate Polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, Polybutylene glycol dimeta Relate, or dimethacrylate compounds such as 2,2′-bis (4-methacryloxydiethoxyphenyl) propane, trimethacrylate compounds such as trimethylolpropane trimethacrylate or trimethylolethane trimethacrylate, methylenebisacrylamide, divinylbenzene, etc. These may be used alone or in combination of two or more.

  In addition to the polymerization initiator and surfactant used in emulsion polymerization, a chain transfer agent, further a neutralizing agent, and the like may be used according to a conventional method. In particular, ammonia and inorganic alkali hydroxides such as sodium hydroxide and potassium hydroxide are preferred as the neutralizing agent.

  In the present invention, the high Tg resin fine particles (a) and the low Tg resin fine particles (b) may be mixed with other components of the ink composition as fine particle powder, but preferably the resin fine particles are dispersed in an aqueous medium, It is preferable that after the emulsion (polymer emulsion) is formed, it is mixed with the other components of the ink composition.

  In the ink composition of the present invention, the total amount of the resin fine particles (a) and the resin fine particles (b) is not particularly limited, but is preferably 6% by weight or less of the total weight of the ink composition. More preferably, it is 1 to 5% by weight. If the total amount of the resin fine particles (a) and the resin fine particles (b) exceeds 6% by weight, printing failure may occur. Further, when the total amount of the resin fine particles (a) and the resin fine particles (b) is less than 0.1% by weight, uneven gloss may occur. The weight ratio (a / b) between the high Tg resin fine particles (a) and the low Tg resin fine particles (b) is 10/1 to 1/10 in terms of the balance between the OD value and the fixability. preferable.

  The high Tg resin fine particles (a) and the low Tg resin fine particles (b) preferably have an average particle diameter of 50 to 250 nm, particularly 60 to 200 nm, from the viewpoint of dispersion stability in the ink composition. In addition, as the high Tg resin fine particles (a) and the low Tg resin fine particles (b), any of a single phase structure and a multiphase structure (core-shell type) can be used.

The high Tg resin fine particles (a) and the low Tg resin fine particles (b) are blended in the ink composition of the present invention as an emulsion in terms of ink adjustment for adjusting a uniform ink and ink stability. It is preferable.
In the present invention, the “resin fine particles” are particles in which a water-insoluble resin is dispersed in the form of particles in a dispersion medium mainly composed of water, or the water-insoluble resin is particles in a dispersion medium mainly composed of water. It means that which is dispersed in a shape, and further includes the dried product. In the present invention, the term “emulsion” means a solid / liquid dispersion called dispersion, latex or suspension. Moreover, it is preferable that an emulsion is anionic from a viewpoint of the dispersion stability improvement of the sulfonated resin fine particle (c) mentioned later.

  As the polymerization initiator, those used for normal radical polymerization are used, for example, potassium persulfate, ammonium persulfate, hydrogen peroxide, azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, Examples thereof include peracetic acid, cumene hydroperoxide, t-butyl hydroxy peroxide, paramentane hydroxy peroxide, and the like. In particular, as described above, when the polymerization reaction is performed in water, a water-soluble polymerization initiator is preferable.

  Examples of the emulsifier used in the polymerization reaction include those generally used as an anionic surfactant, a nonionic surfactant or an amphoteric surfactant in addition to sodium lauryl sulfate.

  Examples of the chain transfer agent used in the polymerization reaction include t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, xanthogens such as dimethylxanthogen disulfide, diisobutylxanthogen disulfide, dipentene, indene, 1,4- Examples include cyclohexadiene, dihydrofuran, and xanthene.

The sulfonated resin constituting the fine particles (c) used in the ink composition of the present invention is, for example,
(S) a diene repeating unit containing a sulfonic acid group;
(V) A copolymer containing a vinyl-based repeating unit not containing a sulfonic acid group. In the copolymer, the number of moles (m) of the sulfonic acid group-containing diene-based repeating unit is the total number of moles of all the repeating units constituting the copolymer [that is, the sulfonic acid group-containing diene-based repeating unit. The total number of moles (m + n) of the number of moles of return units (m) and the number of moles (n) of vinyl-based repeating units not containing sulfonic acid groups] is preferably 5% to 90%, more preferably 10%. % To 80%. That is, the formula:
[M / (m + n)] × 100
The sulfonation rate calculated from is preferably 5% to 90%, more preferably 10% to 80%.

  Each of the repeating units (s) and (v) is derived from a sulfonic acid group-containing diene monomer (or a sulfonic acid group-free diene monomer) and a sulfonic acid group-free vinyl monomer. The copolymer may be a block copolymer or a random copolymer. The copolymer is a copolymer obtained by sulfonated copolymer of a sulfonic acid group-free diene monomer and a sulfonic acid group-free vinyl monomer, or a sulfonic acid group-containing copolymer. It can be a copolymer obtained by copolymerization of a diene monomer and a sulfonic acid group-free vinyl monomer.

The diene monomer is preferably a diene compound having 4 to 10 carbon atoms, more preferably 4 to 8 carbon atoms, and still more preferably a diene compound having 4 to 6 carbon atoms. Specific examples of the diene monomer include 1,3-butadiene, 1,2-butadiene, 1,2-pentadiene, 1,3-pentadiene, 2,3-pentadiene, isoprene, 1,2-hexadiene, 1 , 3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,3-hexadiene, 2,4-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene 1,2-heptadiene, 1,3-heptadiene, 1,4-heptadiene, 1,5-heptadiene, 1,6-heptadiene, 2,3-heptadiene, 2,5-heptadiene, 3,4-heptadiene, 3, , 5-heptadiene, cyclopentadiene, dicyclopentadiene, or ethylidene norbornene, and branched carbon Various aliphatic or alicyclic dienes atoms 4-7 can be exemplified. These diene monomers can be used alone or in combination of two or more. Particularly preferred is 1,3-butadiene or isoprene.
The sulfonic acid group-containing diene monomer can be obtained by sulfonating the diene monomer.

  As the vinyl monomer, an aromatic monomer which is optionally substituted with an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms) (preferably an aromatic monomer having 6 to 10 carbon atoms). , For example, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, or vinylnaphthalene; (meth) acrylic acid alkyl ester (preferably alkyl ester having 1 to 4 carbon atoms) For example, methyl (meth) acrylate, ethyl (meth) acrylate, or butyl (meth) acrylate; mono- or dicarboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, or itaconic acid, Or anhydrides of these dicarboxylic acids; vinylcyan compounds such as (meth) acrylonitrile, vinyl chloride Le, vinylidene chloride, vinyl ethyl ketone, vinyl acetate, and (meth) acrylamide, or (meth) unsaturated compounds such as glycidyl acrylate. These vinyl monomers can be used alone or in combination of two or more. Of these vinyl monomers, styrene is preferred.

〔式中、Ｒ^１１、Ｒ^１２、Ｒ^１３、及びＲ^１４は、それぞれ独立して、水素原子、炭素原子数１〜６の脂肪族炭化水素基、又は炭素原子数１〜４のアルキル基で置換されていることのある炭素原子数６〜１０の芳香族炭化水素基であり、ｐ及びｑは、それぞれ独立して１以上の整数であり、［ｐ／（ｐ＋ｑ）］が０．５以上であり、各繰返単位は、ランダム状又はブロック状に存在することができる〕
で表される中間共重合体を更にスルホン化することによって得られる一般式（１）：

〔式中、Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４、ｐ、及びｑ前記と同じ意味であり、Ｘは水素原子又は対イオンである〕
で表される共重合体を挙げることができる。 Examples of the copolymer obtained by sulfonating a copolymer of a sulfonic acid group-free diene monomer and a sulfonic acid group-free vinyl monomer include, for example, a sulfonic acid group-free diene monomer and a sulfonic acid group. General formula (1a) obtained by copolymerization with a non-containing vinyl monomer:

[Wherein, R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. An aromatic hydrocarbon group having 6 to 10 carbon atoms that may be substituted; p and q are each independently an integer of 1 or more; and [p / (p + q)] is 0.5 or more. And each repeating unit can be present in random or block form]
General formula (1) obtained by further sulfonation of the intermediate copolymer represented by:

[Wherein R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , p, and q have the same meaning as described above, and X is a hydrogen atom or a counter ion]
The copolymer represented by these can be mentioned.

  As a method of sulfonating an intermediate copolymer of a sulfonic acid group-free diene monomer and a sulfonic acid group-free vinyl monomer, a known method, for example, edited by The Chemical Society of Japan, New Experiment Course (Vol. 14 III) , Page 1773), or methods described in JP-A-2-227403 or JP-A-11-217525. That is, the double bond portion of the diene unit in the intermediate copolymer can be sulfonated by the sulfonating agent. During the sulfonation, the double bond is opened to form a single bond, or the hydrogen atom is replaced with a sulfonic acid (salt) group while the double bond remains.

  As a sulfonating agent, preferably sulfuric acid anhydride, a complex of sulfuric anhydride and an electron donating compound, sulfuric acid, chlorosulfonic acid, fuming sulfuric acid, hydrogen sulfite (sodium salt, potassium salt, lithium salt, etc.), etc. Can be used.

  The amount of the sulfonating agent used is a desired sulfonation rate in the copolymer represented by the general formula (1) obtained by further sulfonating the intermediate copolymer represented by the general formula (1a). This is the amount.

  In the sulfonation, a solvent inert to a sulfonating agent such as sulfuric anhydride can be used. Examples of the solvent include halogenated hydrocarbons such as chloroform, nitro compounds such as nitromethane, liquid sulfur dioxide, Mention may be made of aliphatic hydrocarbons such as propane, and ether solvents such as dioxane and tetrahydrofuran. These solvents can be used alone or in admixture of two or more. The sulfonation reaction temperature is usually -70 to 200 ° C, preferably -30 to 50 ° C.

〔式中、Ｙは水素原子又は対イオンである〕
で表されるスルホン酸基含有ジエン系モノマーと、一般式（２ｂ）：

〔式中、Ｒ^２１、Ｒ^２２、Ｒ^２３、及びＲ^２４は、それぞれ独立して、水素原子、炭素原子数１〜６の脂肪族炭化水素基、又は炭素原子数１〜４のアルキル基で置換されていることのある炭素原子数６〜１０の芳香族炭化水素基である〕
で表されるスルホン酸基非含有ビニル系モノマーとを反応させ、一般式（２）：

〔式中、Ｒ^２１、Ｒ^２２、Ｒ^２３、Ｒ^２４、及びＹは、前記と同じ意味であり、ｒ及びｓは、それぞれ独立して１以上の整数である〕
で表される共重合体を調製することによって得ることができる。 In the ink composition of the present invention, the copolymer used as the resin fine particles (c) can be obtained by copolymerization of a sulfonic acid group-containing diene monomer and a sulfonic acid group-free vinyl monomer. This copolymer is, for example, the general formula (2a):

[Wherein Y is a hydrogen atom or a counter ion]
A sulfonic acid group-containing diene monomer represented by the general formula (2b):

[Wherein R ²¹ , R ²² , R ²³ , and R ²⁴ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. It is an aromatic hydrocarbon group having 6 to 10 carbon atoms that may be substituted.
And a sulfonic acid group-free vinyl monomer represented by general formula (2):

[Wherein, R ²¹ , R ²² , R ²³ , R ²⁴ , and Y have the same meaning as described above, and r and s are each independently an integer of 1 or more.]
It can obtain by preparing the copolymer represented by these.

  The weight average molecular weight of the sulfonated copolymer used in the present invention is not particularly limited, but is preferably 1,000 to 100,000, more preferably 2,000 to 80,000. When the weight average molecular weight is less than 1,000, the effect may be lost, and when it exceeds 100,000, the reliability of the print may be impaired.

  In the ink composition of the present invention, a basic compound can be allowed to act on the sulfonated copolymer used as the resin fine particles (c). Examples of the basic compound include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; alkali metal alkoxides such as sodium methoxide; carbonates such as sodium carbonate; methyl lithium, propyl sodium, and methyl magnesium. Organometallic compounds such as chloride, diethylmagnesium, diethylzinc, triethylaluminum, or triisobutylaluminum; amines such as aqueous ammonia, trimethylamine, pyridine, or piperazine; metal compounds such as sodium, lithium, potassium, calcium, or zinc Can be mentioned. These basic compounds can be used alone or in combination of two or more. Among these basic compounds, alkali metal hydroxides or ammonia water are preferable, and sodium hydroxide or lithium hydroxide is particularly preferable.

  The usage-amount of a basic compound is 2 mol or less with respect to 1 mol of used sulfonating agents, Preferably it is 1.3 mol or less. In this reaction, the basic compound can be used in the form of an aqueous solution, or an organic solvent inert to the basic compound (for example, an aromatic hydrocarbon compound such as benzene or toluene; methanol or ethylene glycol). It can also be dissolved in alcohols such as

  The structure of the sulfonated copolymer can be confirmed by absorption of sulfonic acid groups by infrared absorption spectrum, the composition ratio can be confirmed by elemental analysis, etc., and the structure can be confirmed by nuclear magnetic resonance spectrum. can do.

  The sulfonated copolymer prepared by the above method can be used as an emulsion in water. The re-emulsification method is carried out by stirring and mixing the sulfonated copolymer or the organic solvent solution of the product before neutralization with water or the alkali compound, emulsifying the mixture, and then removing the organic solvent while leaving water. It can be obtained by removing. For this re-emulsification, a general method can be adopted, for example, a method of adding water to the organic solvent solution of the sulfonated copolymer while stirring, an organic solvent of the sulfonated copolymer while stirring. A method of adding a solvent solution into water, a method of simultaneously adding water and an organic solvent solution of a sulfonated copolymer and stirring them can be used.

  Here, examples of the organic solvent used for re-emulsification include aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane and heptane, ketone solvents such as acetone and methyl ethyl ketone, ether solvents such as tetrahydrofuran and dioxane. Solvents, ester solvents such as ethyl acetate and butyl acetate, alcohol solvents such as methanol, ethanol and isopropyl alcohol are used. These solvents may be used alone or in combination of two or more.

  The amount of the organic solvent used in the re-emulsification is preferably 20 to 5,000 parts by weight, more preferably 50 to 2,000 parts by weight with respect to 100 parts by weight of the sulfonated copolymer. . If the amount is less than 20 parts by weight, a stable re-emulsified product cannot be obtained. On the other hand, if the amount exceeds 5,000 parts by weight, productivity deteriorates. Further, the amount of water used in the re-emulsification is preferably 50 to 10,000 parts by weight, more preferably 100 to 5,000 parts by weight with respect to 100 parts by weight of the sulfonated copolymer. . If it is less than 50 parts by weight, a stable re-emulsified product cannot be obtained. On the other hand, if it exceeds 10,000 parts by weight, the productivity is deteriorated.

  In the re-emulsification, a surfactant can be used in combination. As this surfactant, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxysorbitan ester, polyoxyethylene alkylamine ether, oleate, laurate, rosinate, dodecylbenzenesulfonate And anionic surfactants such as polyoxyethylene alkyl ether sulfates, and cationic surfactants such as octyltrimethylammonium bromide, dioctyldimethylammonium chloride, and dodecylpyridinium chloride. These surfactants can be used alone or in combination of two or more. The surfactant may be used by dissolving or dispersing in an organic solvent solution of a sulfonated copolymer, or may be used by dissolving or dispersing in water. The amount of the surfactant used is usually 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the sulfonated copolymer. When it exceeds 15 parts by weight, the purity of the sulfonated emulsion (re-emulsified product) is lowered.

  In order to adjust the pH in the system, an alkali compound such as sodium hydroxide or lithium hydroxide, or an inorganic acid such as hydrochloric acid or sulfuric acid can be added. Moreover, if it is a small quantity, organic solvents other than water can also be used together.

  The particle size of the re-emulsified emulsion of the sulfonated copolymer thus obtained is usually 1 to 500 nm, preferably 2 to 100 nm.

  In the ink composition of the present invention, the total amount of the resin fine particles (a), the resin fine particles (b), and the resin fine particles (c) is preferably 1% by weight or more of the total weight of the ink composition. More preferably, it is 1.5 to 8% by weight. When the total amount of the resin fine particles (a), the resin fine particles (b), and the resin fine particles (c) is less than 1% by weight, gloss unevenness or image deterioration may occur, which exceeds 8% by weight. In some cases, the storage stability of the ink is lowered. In the ink composition of the present invention, the content of the resin fine particles (c) alone is not particularly limited, but is preferably 0.1% by weight to 3% by weight.

  The ink composition of the present invention can contain, for example, a pH-adjusted resin emulsion or a polyalkylene type emulsion as a resin component in addition to the resin fine particles. Here, the pH-adjusted resin emulsion refers to an ethylenically unsaturated carboxylic acid monomer and other monomers copolymerizable therewith, with an alcoholic hydroxyl group-containing water-soluble polymer compound or copolymerizable surfactant. It is an emulsion comprising, as a resin component, a pH-adjusted resin obtained by adjusting the pH of a copolymer having an acid value of 40 or less obtained by polymerization in the presence of an inorganic base. Moreover, as said polyalkylene type | mold emulsion, a commercially available thing can be used. For example, AQ593, AQ513, or PEM-17 marketed by Big Chemie Japan can be used.

  The colorant used in the ink composition of the present invention is not particularly limited and is a dye or a pigment, and either a pigment, an inorganic pigment or an organic pigment can be used. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used.

  Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. And organic pigments such as nitro pigments, nitroso pigments, aniline black, fluorescent pigments, and the like. The above pigments can be used alone or in combination of two or more.

  Specific examples of the pigment include carbon black No. 2300, No. 900, HCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B, etc. are Raven 5750, 5250, 5000, 3500, 1255, 700, etc. manufactured by Columbia, and Regal 400R, 330R, 660R, Mogu L, 700, Monarch 800, 880, 900, 1000, 1100, 1300, 1400, etc. are Degussa Color Black FW1, FW2V, FW18, FW200, Color Black S150, S160, S170, Printex 35, U, the same V, the same 140 U, the Special Black 6, the same 5, the same 4 A, the same 4, etc., and may be used as one or a mixture of these.

  Examples of the pigment used in the yellow ink composition include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185, etc., preferably C.I. I. 1 or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128 and 138.

  Examples of the pigment used in the magenta ink composition and the light magenta ink composition include C.I. I. Pigment Red, 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 15: 1, 112, 122, 123, 168, 184, 202, 209 and C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, 209 and C.I. I. One or a mixture of two or more selected from the group consisting of pigment violet 19.

  Further, examples of the pigment used in the cyan ink composition and the light cyan ink composition include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60 and C.I. I. Bat blue 4, 60, and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and one or a mixture of two or more selected from the group consisting of 60.

  According to a preferred embodiment of the present invention, the pigment used in the present invention preferably has an average particle size in the range of 10 to 200 nm, more preferably about 50 to 150 nm.

  The amount of the pigment used in the present invention may be determined as appropriate, but is preferably 1% by weight or less, more preferably 0.9% by weight or less, and most preferably based on the total weight of the ink composition. 0.05 wt% to 0.9 wt%. That is, the present invention is particularly effective for an ink composition having a low content of a colorant (particularly a pigment) as compared with a resin content. That is, the ink composition of the present invention is preferably applied to, for example, a light black ink composition, a light cyan ink composition, and a light magenta ink composition.

  According to a preferred embodiment of the present invention, the pigment used in the present invention is preferably added to the ink composition as a pigment dispersion obtained by dispersing the pigment in an aqueous medium with a dispersant. As a preferable dispersant in the ink composition of the present invention, a dispersant, a polymer dispersant or a surfactant conventionally used for preparing a pigment dispersion can be used.

  Examples of polymer dispersants preferably used in the present invention include natural polymers. Specific examples thereof include proteins such as glue, gelatin, casein, and albumin, and natural rubbers such as gum arabic and tragacanth. And glucosides such as saponin, alginic acid and propylene glycol alginate, alginic acid derivatives such as triethanolamine alginate and ammonium alginate, and cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose and ethylhydroxycellulose.

  Examples of another preferred polymer dispersant include synthetic polymers such as polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer. , Acrylic copolymers such as vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid alkyl ester copolymer; styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic Styrene-acrylic acid resin such as acid alkyl ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid alkyl ester copolymer; styrene-maleic acid; Styrene-maleic anhydride; vinyl naphth Tarene-acrylic acid copolymer; vinyl naphthalene-maleic acid copolymer; vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid Mention may be made of vinyl acetate copolymers such as copolymers, vinyl acetate-acrylic acid copolymers, and salts thereof.

  Among the above, in particular, a polymer compound having a carboxyl group (preferably in the form of a salt) (for example, the above-described styrene-acrylic acid resin, styrene-maleic acid resin, styrene-maleic anhydride resin, vinylnaphthalene) -Acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer, vinyl acetate-acrylic acid copolymer), a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group, and a hydrophobic group A polymer composed of a monomer having a hydrophilic group in the molecular structure is preferred.

  Examples of the salt include salts of diethylamine, ammonia, ethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, triethanolamine, diethanolamine, aminomethylpropanol, morpholine, and the like. These (co) polymers preferably have an Mw of 3,000 to 30,000, more preferably 5,000 to 15,000.

  Examples of surfactants preferable as a dispersant include fatty acid salts, higher alkyl dicarboxylates, higher alcohol sulfate esters, higher alkyl sulfonates, condensates of higher fatty acids and amino acids, sulfosuccinate esters, naphthenes. Anionic surfactants such as acid salts, liquid fatty oil sulfate esters, alkylallyl sulfonates; cationic surfactants such as fatty acid amine salts, quaternary ammonium salts, sulfonium salts, phosphoniums; polyoxyethylene alkyl ethers And nonionic surfactants such as polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters, and the like. A person skilled in the art can understand that the surfactant described above also functions as a surfactant when added to the ink composition.

  According to a preferred embodiment of the present invention, the ink composition according to the present invention preferably further comprises 1,2-alkanediol. The 1,2-alkanediol is preferably 1,2-hexanediol.

  The amount of 1,2-alkanediol added may be appropriately determined, but is preferably about 1 to 15% by weight, more preferably about 2 to 10% by weight.

  According to a preferred embodiment of the present invention, it is preferable to use a polyether-modified organosiloxane compound represented by the following formula.

（式中、Ｒ^３１〜Ｒ^３７は、それぞれ独立して、Ｃ_１−６アルキル基であり、ｊ、ｋ及びｇは、それぞれ独立して、１以上の整数であり、ＥＯはエチレンオキシ基であり、ＰＯはプロピレンオキシ基であり、ａ及びｂは０以上の整数であるが、但しａ＋ｂは１以上の整数であり、ＥＯ及びＰＯは、［ ］内においてその順序は問わず、ランダムであってもブロックであってもよい）で表されるポリエーテル変性オルガノシロキサン系化合物である。

(Wherein R ^{31 to} R ³⁷ are each independently a C _1-6 alkyl group, j, k and g are each independently an integer of 1 or more, and EO is an ethyleneoxy group) Yes, PO is a propyleneoxy group, a and b are integers of 0 or more, provided that a + b is an integer of 1 or more, and EO and PO are random in [] regardless of their order. Or may be a block).

As the polyether-modified organosiloxane compound used in the present invention, preferably, in the general formula (3), R ^{31 to} R ³⁷ are independently an alkyl group having 1 to 6 carbon atoms, preferably methyl. It is a group. j, k, and g are each independently an integer of 1 or more, and more preferably 1 or 2. A and b are integers of 0 or more, provided that a + b is an integer of 1 or more.

As the compound represented by the general formula (3), for example, a compound satisfying j = k + 1 is preferable. In the compound represented by the general formula (3), R ^{31 to} R ³⁷ are all methyl groups, j is 2, k is 1, g is 1, and a is 1 or more. A compound in which b is 0 is preferable.

  The compounds represented by the above general formula (3) are commercially available and can be used. For example, commercially available silicon surfactants BYK-345, BYK-346, BYK-347, or BYK-348 are available from Big Chemie Japan.

  The addition amount of the polyether-modified organosiloxane compound may be appropriately determined, but is preferably in the range of about 0.03 to 3% by weight, more preferably about 0.1 to 2% by weight, and more preferably about 0.1 to 2% by weight. Preferably, it is about 0.3 to 1% by weight.

  According to a preferred embodiment of the present invention, the ink composition according to the present invention contains a penetrant. Preferable specific examples of the penetrating agent include glycol ethers and / or acetylene glycol surfactants.

  Specific examples of glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol Mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, diethylene glycol mono- t-butyl ether, 1-methyl -1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether , Dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol-iso-propyl ether These can be used, and can be used as a mixture of one or more of these.

  The amount of glycol ether added is preferably in the range of 1 to 20% by weight, more preferably in the range of 2 to 15% by weight, based on the ink composition.

  According to a preferred embodiment of the present invention, it is preferable to use an alkyl ether of a polyhydric alcohol, particularly ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether. The use of triethylene glycol monoethyl ether or triethylene glycol monobutyl ether is preferred. Most preferred is triethylene glycol monobutyl ether.

  Although the addition amount of the polyhydric alcohol alkyl ether may be appropriately determined, it is preferably about 1 to 10% by weight, more preferably about 3 to 5% by weight.

  On the other hand, preferred specific examples of the acetylene glycol-based surfactant that can be used in the present invention include compounds represented by the following formulae.

（式中、０≦ｅ＋ｆ≦５０であり、Ｒ^４１〜Ｒ^４４は、それぞれ独立してアルキル基である）
上記一般式（４）で表される化合物の中で特に好ましくは、２，４，７，９−テトラメチル−５−デジン−４，７−ジオール、３，６−ジメチル−４−オクチン−３，６−ジオール、３，５−ジメチル−１−ヘキシン−３−オール等を挙げることができる。上記一般式（４）で表されるアセチレングリコール系界面活性剤として市販品を利用することも可能であり、その具体例としてサーフィノール１０４、８２、４６５、４８５又はＴＧ（いずれもAirProduct and Chemicals. Inc. より入手可能）、オレフィンＳＴＧ、オレフィンＥ１０１０（以上、日信化学社製（商品名））を挙げることができる。

(In the formula, 0 ≦ e + f ≦ 50, and R ^{41 to} R ⁴⁴ are each independently an alkyl group)
Among the compounds represented by the general formula (4), 2,4,7,9-tetramethyl-5-decin-4,7-diol and 3,6-dimethyl-4-octyne-3 are particularly preferable. , 6-diol, 3,5-dimethyl-1-hexyn-3-ol, and the like. Commercially available products may be used as the acetylene glycol surfactant represented by the general formula (4), and specific examples thereof include Surfynol 104, 82, 465, 485, and TG (both are AirProduct and Chemicals. Inc.), Olefin STG, Olefin E1010 (above, Nissin Chemical Co., Ltd. (trade name)).

  The addition amount of the acetylene glycol surfactant may be appropriately determined, but is preferably in the range of about 0.1 to 10% by weight, more preferably in the range of about 0.1 to 2% by weight with respect to the ink composition. is there.

  In the ink composition of the present invention, the water can be pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water. In addition, the use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold and bacteria can be prevented when the ink composition is stored for a long period of time.

  The water-soluble organic solvent is preferably a low-boiling organic solvent, and examples thereof include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol, and iso-butanol. , N-pentanol and the like. In particular, monohydric alcohol is preferable. The low boiling point organic solvent has an effect of shortening the drying time of the ink.

  The amount of the low-boiling organic solvent added is preferably in the range of about 5% by weight or less, more preferably in the range of about 2% by weight or less with respect to the ink composition.

  According to a preferred embodiment of the present invention, the ink composition according to the present invention preferably further includes a wetting agent composed of a high boiling point organic solvent. Preferred examples of the high boiling point organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, triglyceride, Polyhydric alcohols such as methylolethane and trimethylolpropane, urea, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like, It is also possible to use it as a mixture of two or more. In particular, glycerin, triethylene glycol monobutyl ether, 2-pyrrolidone, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, diethylene glycol monobutyl ether, and urea are preferable.

  The amount of these added is preferably in the range of about 1 to 20% by weight, more preferably in the range of about 5 to 10% by weight with respect to the ink composition.

  The ink composition according to the present invention may further contain a surfactant. Examples of surfactants include anionic surfactants (eg, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, ammonium salt of polyoxyethylene alkyl ether sulfate), nonionic surfactants (eg, polyoxyethylene alkyl) Ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, etc.). These can be used alone or in combination of two or more.

  The ink composition according to the present invention may further contain a nozzle clogging preventive agent, an antiseptic, an antioxidant, a conductivity adjusting agent, a pH adjusting agent, a viscosity adjusting agent, a surface tension adjusting agent, an oxygen absorber, and the like. it can.

  Examples of preservatives and fungicides include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzthiazoline-3-one ( ICI's Proxel CRL, Proxel BND, Proxel GXL, Proxel XL-2, Proxel TN) and the like.

  Furthermore, examples of pH adjusters, solubilizers or antioxidants include amines such as diethanolamine, triethanolamine, propanolamine, morpholine and their modified products, potassium hydroxide, sodium hydroxide, lithium hydroxide, etc. Inorganic salts, ammonium hydroxide, quaternary ammonium hydroxide (tetramethylammonium, etc.), carbonates such as potassium carbonate, sodium carbonate, lithium carbonate and other phosphates, or N-methyl-2-pyrrolidone, urea, thiourea And L-ascorbic acid and salts thereof, such as ureas such as tetramethylurea, allophanates such as allophanate and methylallohanate, biurets such as biuret, dimethylbiuret and tetramethylbiuret.

  In addition, the ink composition according to the present invention may contain an antioxidant and an ultraviolet absorber, and examples thereof include Ciba Geigy's Tinuvin 328, 900, 1130, 384, 292, 123, 144, 622, 770, and 292. Irgacor 252 153, Irganox 1010, 1076, 1035, MD1024, lanthanide oxide, and the like.

  The ink composition according to the present invention can be produced by dispersing and mixing the above components by an appropriate method. For example, the pigment, polymer dispersant and water are first mixed with a suitable dispersing machine (eg, ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid mill, ultrasonic homogenizer, jet mill, ang mill, etc.) Then, a uniform pigment dispersion was prepared, and then a separately prepared sulfonated copolymer (referred to as “emulsion” in the examples), water, water-soluble organic solvent, sugar, pH adjuster, preservative, An ink solution is prepared by adding a mold agent or the like and sufficiently dissolving it. After stirring sufficiently, filtration is performed to remove the coarse particle size and foreign matters that cause clogging, and the desired ink composition is obtained.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention. Unless otherwise specified, “%” means “% by weight”.

<Preparation of emulsion>
(1) Preparation of Emulsion 1 [EM1] In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer, 900 g of ion-exchanged water and 3 g of sodium lauryl sulfate were charged, and 70 ° C. while substituting with nitrogen under stirring. The temperature was raised to. The internal temperature was kept at 70 ° C., 4 g of potassium persulfate was added as a polymerization initiator, and after dissolution, 450 g of ion exchange water, 3 g of sodium lauryl sulfate, 20 g of acrylamide, 130 g of styrene, 780 g of 2-ethylhexyl acrylate, methacrylic acid An emulsion prepared by adding 30 g and 2 g of ethylene glycol dimethacrylate to the stirring was continuously dropped into the reaction solution over 4 hours. After completion of the dropwise addition, aging was performed for 3 hours. The obtained aqueous emulsion was cooled to room temperature, and then ion-exchanged water and ammonia water were added to adjust the solid content to 40% by weight and pH 8.
The glass transition temperature of the resin particles in the obtained aqueous emulsion was −50 ° C.

(2) Preparation of Emulsion 2 [EM2] A reaction vessel equipped with a stirrer, reflux condenser, dropping device, and thermometer was charged with 900 g of ion-exchanged water and 3 g of sodium lauryl sulfate, and 70 ° C. while substituting nitrogen with stirring. The temperature was raised to. The internal temperature is kept at 70 ° C., 4 g of potassium persulfate is added as a polymerization initiator, and after dissolution, 450 g of ion exchange water, 3 g of sodium lauryl sulfate, 20 g of acrylamide, 500 g of styrene, 410 g of butyl acrylate, 30 g of methacrylic acid, and ethylene An emulsion prepared by adding 2 g of glycol dimethacrylate to the stirring was continuously dropped into the reaction solution over 4 hours.
After completion of the dropwise addition, aging was performed for 3 hours. The obtained aqueous emulsion was cooled to room temperature, and then ion-exchanged water and ammonia water were added to adjust the solid content to 40% by weight and pH 8.
The glass transition temperature of the resin particles in the obtained aqueous emulsion was 15 ° C.

(3) Preparation of Emulsion 3 [EM3] An emulsion having the following composition was prepared by the following operation. First, 100 g of dioxane was placed in a glass reaction vessel, and 11.8 g of anhydrous sulfuric acid was added thereto while maintaining the internal temperature at 25 ° C., and the mixture was stirred for 2 hours to obtain an anhydrous sulfuric acid-dioxane complex.
Subsequently, 100 g of tetrahydrofuran (THF) solution (concentration 15%) of isoprene / styrene / isoprene ternary block copolymer (weight ratio = 10/80/10; molecular weight = 10000) was mixed with the total amount of the anhydrous sulfuric acid-dioxane complex. The mixture was added while maintaining the internal temperature at 25 ° C., and stirring was further continued for 2 hours.

  Thereafter, 1200 g of water, 7.1 g of sodium hydroxide, and 1 g of sodium dodecylbenzenesulfonate were placed in the flask, and the internal temperature was kept at 40 ° C. Into this, the whole amount of the diene copolymer sulfonated solution was added dropwise over 1 hour while keeping the internal temperature at 40 ° C. After the dropwise addition, the mixture was stirred at 40 ° C. for 2 hours, and then the solvent was removed by distillation under reduced pressure while leaving water, and a diene copolymer sulfonated emulsion having a concentration of 15% (hereinafter sometimes referred to as “emulsion 1”). Got. The average particle size of the emulsion 1 was 30 nm, the solid content was 15% by weight, and the molar content of the sulfonic acid group-containing diene repeating unit was 20% by mole.

(4) Preparation of emulsion 4 [EM4] 60 parts of ethyl methacrylate, 36 parts of methyl methacrylate, 4 parts of methacrylic acid, 3 parts of octyl thioglycolate as molecular weight regulator, 1 part of polyvinyl alcohol and 280 parts of ion-exchanged water were stirred. Mixing to prepare a dispersion of the monomer mixture.
In another reactor equipped with a stirrer, 130 parts of ion-exchanged water and 2 parts of potassium persulfate were charged, the temperature was raised to 80 ° C., and the dispersion of the monomer mixture was continuously added over 4 hours for polymerization. . After completion of the continuous addition, a post-reaction was performed at 80 ° C. for 30 minutes. The polymerization conversion rate was 99% or more.
Next, 10% aqueous sodium hydroxide solution in an amount corresponding to the charged methacrylic acid and an equimolar amount of sodium hydroxide was added to the reactor, and after heat treatment at 80 ° C. for 1 hour, an appropriate amount of ion-exchanged water was added. In addition, a pH-adjusted resin emulsion A having a solid content concentration of 15% was obtained. The acid value of this pH-adjusted resin emulsion A was 30.

(5) Preparation of Emulsion 5 [EM5] A commercially available product (AQ593: manufactured by Big Chemie Japan Co., Ltd.) was used as a polypropylene type emulsion (polyalkylene type emulsion).

<Examples 1-4 and Comparative Examples 1-3>
An ink composition having the following composition was prepared.
Carbon black 0.2% by weight
C. I Pigment Blue 60 0.07% by weight
Resin emulsion (EM1-EM5) Amounts listed in Table 1 Glycerin 17% by weight
1,2-hexanediol 5% by weight
Triethanolamine 0.5% by weight
EDTA 0.02% by weight
BYK348 0.5% by weight
The amount which makes the whole water 100%. Incidentally, BYK348 is a silicon-based surfactant (Big Chemie Japan Co., Ltd.), and EDTA is ethylenediaminetetraacetic acid.

<Evaluation of the physical properties>
(1) Printing stability After filling the ink compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 into an ink jet printer [PM4000PX: manufactured by Seiko Epson Corporation] and performing nozzle check printing, the power is turned on. After stopping and leaving at 50 degreeC for 3 days, it returned to normal temperature and printed. The printing stability at that time was evaluated in the following three stages. The evaluation results are shown in the column “Evaluation 1” in Table 1.
A: Printed normally without any problems after leaving;
B: Almost no problem, but slight discharge disturbance
C: Discharge irregularities are not suitable for practical use.

(2) Abrasion resistance The ink compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were filled into an ink jet printer [PM4000PX: manufactured by Seiko Epson Corporation], and solid printing was performed on photographic paper (gloss). Immediately thereafter, it was examined whether or not the print could be peeled off by rubbing with a finger, and the rubbing resistance was evaluated in the following three stages. The evaluation results are shown in the column “Evaluation 2” in Table 1.
A: No problem with rubbing;
B: Slightly peeled off, but no problem in practical use;
C: Not fixed.

(3) Gas resistance evaluation About the ink composition prepared in Examples 1-4 and Comparative Examples 1-3, gas resistance evaluation was performed in the following ways.
Printing is performed using an ink jet printer [PM-920C (manufactured by Seiko Epson Corporation)] with an applied duty (Duty) adjusted so that OD (Optical Density) falls within a range of 0.9 to 1.1. It was. Using the ozone weather meter OMS-H type [trade name; manufactured by Suga Test Instruments Co., Ltd.], the obtained printed matter was subjected to ozone (over 40 hours under conditions of 24 ° C. and relative humidity 60% RH). 1 ppm).

About each printed matter after exposure, generation | occurrence | production of the white powder-like spot was observed with the naked eye, and it determined based on the following criteria. The evaluation results are shown in the column “Evaluation 3” in Table 1.
Evaluation A: Good gas resistance;
Evaluation B: No problem in practical use;
Evaluation C: Unbearable for practical use.

  The ink composition of the present invention does not cause a phenomenon that white powder-like spots are generated in a recorded image even when the obtained recorded matter is exposed to air for a long period of time. There is no clogging, and there is no gloss unevenness in the recorded material, and a recorded material excellent in abrasion resistance can be obtained.

Claims (9)

A pigment comprising: (a) fine particles made of a resin having a glass transition point of 10 ° C. or higher; (b) fine particles made of a resin having a glass transition point of 0 ° C. or lower; and (c) fine particles made of a sulfonated resin. In an ink composition for ink jet recording , characterized by comprising 1% by weight or less of the total weight of the ink composition. The ink composition for inkjet recording according to claim 1, wherein the total amount of the resin fine particles (a), the resin fine particles (b), and the resin fine particles (c) is 1% by weight or more of the total weight of the ink composition. object. The ink composition for ink jet recording according to claim 1 or 2 , wherein the total amount of the resin fine particles (a) and the resin fine particles (b) is 6% by weight or less of the total weight of the ink composition.   The total amount of the resin fine particles (a), the resin fine particles (b), and the resin fine particles (c) is 1.5 wt% to 8 wt% of the total weight of the ink composition. The ink composition for ink jet recording according to any one of the above. The ink composition for inkjet recording according to any one of claims 1 to 4 , wherein a glass transition point of the resin constituting the resin fine particles (a) is 10 ° C or higher and 150 ° C or lower. The ink composition for inkjet recording according to any one of claims 1 to 5 , wherein a glass transition point of the resin constituting the resin fine particles (b) is 0 ° C or lower and minus 80 ° C or higher. The resin constituting the resin fine particles (c) includes a sulfonic acid group-containing diene-based repeating unit and a sulfonic acid group-free vinyl-based repeating unit, and the sulfonic acid group-containing diene-based repeating unit in the copolymer. The ink composition for inkjet recording according to any one of claims 1 to 6 , which is a copolymer having a molar content of 5 to 90 mol%. An ink jet recording method using the ink composition for ink jet recording according to any one of claims 1 to 7 . Recording images obtained using the ink composition for ink jet recording according to any one of claims 1-7.